PRESIDENTIAL ADDRESS

Two Decades of Gastrointestinal Research A Perspective

Lloyd 1111. Nyhus, MD, Chicago, Illinois

It is an honor for me to stand before you as the fifteenth President of the Society for Surgery of the Alimentary Tract. Although our Society is young in terms of years, it has matured rapidly because of superb leadership from the very outset. The words “traditions of excellence” cannot be applied to such a youthful organization; however, the elected officers, members of the Board of Trustees, and the total membership of 718 are striving for excellence-traditions, if needed, will come later. On October 1, 1952, I entered the gastrointestinal research laboratory of the late Doctor Henry N. Harkins at the University of Washington, Seattle. Since this invitation into the arena of laboratory and clinical studies, it has been my good fortune to work through the ensuing years with one hundred five talented colleagues from seventeen different countries. My heartfelt words of “thank you” go to each and everyone of these individuals. It is presumptuous to suggest that we can cover in this presentation all the advances made in our knowledge of gastrointestinal function during the past two decades. The story of the hormone gastrin in itself has been the subject of books and innumerable articles in the medical and surgical scientific literature. Therefore, I have selected two areas of interest for analysis today, namely, (1) the current status of vagotomy in the treatment of ulcer disease of the duodenum and (2) the application of molecular biology to gastrointestinal research. From the Department of Surgery. The Abraham Lincoln School of Medicine. The Universitv of Illinoisat the Medical Center. Chicaoo. Reprint requests should be addressed to Lloyd M. Nihus. MD, 840 South Wood St., Chicago, Illinois60612. Presented at the Sixteenth Annual Meeting of the Society for Surgery of the Alimentary Tract, San Antonio, Texas, May 20-21, 1975.

Vofume 131, January 1976

The Current Treatment of Vagotomy In Treatment of Duodenal Ulcer Disease Truncal Gastric Vagotomy. Although limited clinical application of vagal section was first proposed and practiced by Latarjet [1] of Lyon, France, it was not until Lester Dragstedt of Chicago proposed its potential clinical importance in 1943 [2] that this method of treatment was taken seriously. Interest in the technic waxed and waned, but it was not until the early 1960s that truncal vagotomy was used by a majority of surgeons in the United States for the treatment of duodenal ulcer disease. Parenthetically, note that the passage of two decades was necessary for truncal gastric vagotomy to attain this predominant position. From this large clinical experience, we have learned that the single most important advantage of truncal vagotomy has been the decrease in mortality (less than 1 per cent for elective operations), especially when used in conjunction with a drainage procedure. The lives of literally thousands of patients have been preserved. Contrariwise, the record of permanent cure for the ulcer diathesis after truncal gastric vagotomy has not been outstanding. Perusal of the surgical literature indicates a recurrent ulcer rate ranging from 0 to 28 per cent [3-121. (Table I.) This problem is found when vagotomy is combined with a procedure such as gastrojejunostomy or pyloroplasty, but when vagotomy is combined with partial gastrectomy or antrectomy (removal of both the cephalic and gastric phases of acid stimulation) [13], a lower recurrent ulcer rate is noted [9,10,14-161. (Table II.) As experience with truncal gastric vagotomy was gained, experimental as well as clinical reports

3

TABLE

I

Operative Mortality and Recurrent Ulcer Rate after Truncal Vagotomy plus Drainage Procedure (elective) Number of Patients

Authors Lynch et al 13)

Nobles

[4]

Nobles [4] Bryant, Klein, and Griffen [5] Goligher et al [6] Stempien et al [ 71 Kronborg [8] Hoerr and Ward [9] Howard et al [IO] Kennedy et al [II] Dragstedt II and LUIU [12] * Followed t Followed $ Followed

TABLE

II

Recurrent Ulcer (per cent)

Operative Mortality (per cent)

123 102

13 24”

1.4

89 112

28* 18

.._ 0

112 161 500 323 100 46 100

7 to 10 27$ 6 12.7 10 6 2

1

0 b:$ 0.7 0 0 1

10 years from operation. 15 years from operation. 10 to 18 years from operation.

Operative Mortality and Recurrent Ulcer Rate after Truncal Vagotomy plus Distal Gastrectomy (elective)

Number of Patients

Recurrent Ulcer (per cent)

...

1.5

1.9*

118 121 86

. . . 3.3 0

...

‘$3

... 4

0 7* 0

[ Z6]

154

10

0.7

* Includes emergency

operations.

Authors Farmer, Harrower, and Smithwick

Operative Mortality (per cent)

iI41 Hoerr and Ward [9] Berger, Kock, and Norberg [ 151 Howard, Murphy, and Humphrey IlO] Svensson

3.4

began to appear concerning deleterious side effects on the biliary tract, pancreas, and small intestine [I?-341. (Table III.) Some of the observed alterations were transient in nature and the magnitude of various problems did not seem great enough to negate the clinical effectiveness of the procedure. Yet, as the mass of evidence accumulates that extragastric vagal section creates significant abnormalities in several organ systems, it does not seem appropriate to continue its use. This is especially true since other technics of vagotomy are available that protect the extragastric vagi. Selective Gastric Vagotomy. The history of the development of this technic has been well docu-

4

mented. It suffices to indicate that Charles Griffith and Henry Harkins deserve the credit for establishing the procedure as a viable and important technic [35). Philosophically, it is difficult to argue against a concept that is dedicated to the preservation of the extragastric vagal fibers. Yet, there has been a peculiar resistance to its use by surgeons in the United States and Great Britain. Contrariwise, surgeons of Scandinavia, continental Europe, and Japan have worked extensively with selective gastric vagotomy in the laboratory and in the clinical setting. What has been the record of this modification of gastric vagotomy? Until recently, a clear-cut advantage of the selective technic was not demonstrated. Pathophysiologic advantages from laboratory studies are in evidence, but because of the difficulty in setting the experimental controls, skepticism abounds [26,36-401. (Table IV.) Two studies on patients have clearly shown two important attributes of selective gastric vagotomy, namely, (1) a decreased incidence of postvagotomy diarrhea and (2) a decreased incidence of recurrent ulcer. Postoagotomy diarrhea: The clinical importance of explosive diarrhea after vagotomy (not to be confus’ed with the diarrhea of the dumping syndrome) has been questioned by surgeons. At one time, we reported an incidence of postvagotomy diarrhea of 68 per cent [41]. We obviously overinterpreted “change in bowel habit” as diarrhea. Regardless, as reported by Kennedy [40], as many as 28 per cent of patients will be troubled by this complication and, indeed, about 2 per cent will be incapacitated. In their long-term prospective randomized clinical study, Kennedy et al [42] found that patients with selective gastric vagotomy had significantly less diarrhea (8 per cent) than after truncal gastric vagotomy (28 per cent). Recurrent ulcer: Proponents of selective gastric vagotomy have had a rather “snobbish” attitude concerning this “refined” approach to vagotomy. The words “meticulous dissection” are frequently heard; the connotation is that a “better” or truly complete vagotomy to the stomach has been the result of the more tedious and certainly more time-consuming operation. There is evidence that a better technical gastric vagotomy can be attained by the selective procedure. Sawyers and Scott [43] have reported on a series of prospective randomized patients in whom they have compared the operations of selective vagotomy plus antrectomy and selective vagotomy plus pyloroplasty. Follow-up greater than seven years demonstrates a recurrent ulcer rate of 2.5

The Amodcan

Joumalot

SurQory

Presidential Address

TABLE

III

Changes Noted in Function of Biliary Tract, Pancreas, and Small Intestine after Truncal Vagotomy Changes

Biliary Tract Increase in volume of gallbladder in onset and duration of gallbladder contraction Decrease in bile flow Decrease in output of bile acids Increase in lithogenic composition of bile Increased (4 times greater than general population) incidence of gall stones in postvagotomy patients

After

Johnson and Boyden [ 171 Rudick and Hutchinson

Trun- Seleccat tive Vagot- Vagot.

Glanville

Study and Duthie

Biliary Tract Dissolution of human gallstones in dog gallbladder Increase in volume of gallbladder

Fletcher and Clark [20] Fields and Duthie [21] Cowie and Clark Tompkins Tompkins

response to vagal stimulation elicited by insulin hypoglycemia Decreased bicarbonate and protein output after meat-stimulation Decrease in plasma glucagon Decrease in insulin response to oral glucose meal

[22]

et al [23] et al [23]

Small Intestine Abnormal motility

Dreiling, Druckerman, Hollander [ 241

Thambugala

and

and Baron

~251 Russell, Thomson, Bloom [26] Russell, Thomson, Bloom [26]

and and

Little effect Small bowel mucosa Atrophy No atrophy

Alvarez et al [27] Ballinger [28] Baldwin

et al [29]

Ballinger et al [30] Yamagishi et al [31] Elliot, Barnett, and Elliot (321

Absorption Transient decrease in d-xylose and glucose Fat and protein, no change

cox [33] Baldwin et al [29] Wastell and Ellis [34] ---

per cent for the former and 2.5 per cent for the latter procedure [44]. This is the first time that vagal section combined with a drainage procedure has been shown to compete favorably with vagotomy plus gastrectomy vis-&vis the incidence of recurrent ulcer when studied in a prospective, random manner. Why has selective gastric vagotomy not become the standard method? Results of finite experiments in the experimental laboratory have sug-

Vahmm 131, Janmy 1978

w

w

[36]

no

yes*

Parkin, Smith, and Johnston [37]

yes

no

Pancreas Decrease in amylase output after insulin hypoglycemia Normal glycemic response to oral glucose Decrease in plasma glucagon after insulin hypoglycemia Decrease in plasma insulin response, (time factor) to oral glucose

McKelvey

yes

no

no

yes

Russell, Thomson, and Bloom [26]

yes

no

Russell, Thomson, and Bloom [26]

yes

no

Postvagotomy Diarrhea Significantly decreased incidence

no

yes

Fujino

et al

1381 Bittner

Kennedy

et al [39]

[ 401

* Parietal cell vagotomy.

pattern

Peristaltic rush Decrease in peristalsis

Authors

[I91

Pancreas

Impairs pancreatic

Studies that Demonstrate Superiority of Selective Vagotomy over Truncal Vagotomy

Authors

1181

Change

TABLE IV

gested that certain abnormal changes occurring after truncal gastric vagotomy are absent after selective gastric vagotomy. There is little evidence, however, that these alterations in organ function found in animal models significantly affect the quality of life in a majority of patients. Part of the problem also relates to the number of patients operated on by individual surgeons. A 2 per cent incidence of incapacitating postvagotomy diarrhea may well escape the notice of most surgeons who perform about thirty truncal vagotomies per year. Similarly at this common level of clinical activity, the individual surgeon will not be aware of the recurrent ulcer rate among his own patients. It is, therefore, apparent why most surgeons continue to use the simpler truncal vagotomy technic: surgeons are not yet convinced that there is evidence in favor of the selective vagotomy operation to warrant the increased time involved at the operating table for its performance. I do not agree with this point of view; there is sufficient laboratory and clinical evidence available to war-

5

Nyhus

rant the use of selective gastric vagotomy in all patients undergoing operation for the elective treatment of duodenal ulcer. Parietal Cell Vagotomy. Unfortunately, there are different names given to the same type of vagotomy, leading to some confusion. Parietal cell vagotomy, highly selective vagotomy, and proximal gastric vagotomy are synonymous terms meaning that the stomach proximal to the antrum is vagally denervated, that extragastric vagal fibers are preserved, and that no drainage procedure accompanies the vagotomy. This is a major change in the operative approach. All surgeons using vagal section for the treatment of duodenal ulcer since 1943 (thirty-two years) have held as sacrosanct the concept that every vagal fiber to the entire stomach must be severed if a successful outcome is to be assured. In 1957, Griffith and Harkins [35] demonstrated that it was anatomically feasible to preserve vagal innervation to the gastric antrum while at the same time severing the vagus nerve supply to the gastric corpus and fundus. The cephalic phase of gastric acid stimulation seemed to be eliminated and minimal or no stasis occurred after “partial gastric vagotomy” in the dog. The authors suggested clinical application of the procedure. The first clinical application of this concept was the selective proximal vagotomy with pyloroplasty as proposed and performed by Holle [45]. Vagal innervation to the antrum was maintained. It did not take long for many interested surgeons to question the necessity of the pyloroplasty as practiced by Holle and thus, parietal cell vagotomy without a concomitant drainage procedure evolved. In 1960, rules were proposed for the successful treatment of duodenal ulcer with vagotomy alone (without gastric resection but with a drainage procedure): (1) the antrum must be vagally denervated; (2) antral stasis must be prevented; and (3) acid flow must continue over the antral mucosa [46]. The new procedure (parietal cell vagotomy) obviously breaks the first rule and may break the second rule. The rules are being given the “acid” test. Factors that May or May Not Alter the Outcome of Parietal Cell Vagotomy. Vagal release of gastrin: This phenomenon has been well documented in dogs prepared with vagally denervated pouches of oxyntic cells (Heidenhain pouches) and vagally innervated pyloric gland pouches. Vagal stimulation by insulin hypoglycemia or sham feeding causes the Heidenhain pouch to secrete acid. Direct vagal stimulation of acid secretion from the

6

parietal cell by large doses of insulin is possible in the absence of the antrum and small intestine [47]. The secretion of acid in this setting is probably unphysiologic, since the presence of the gastrin mechanism seems to be necessary for secretion of acid during sham feeding experiments [48]. A definite synergism exists between vagal stimulation and gastrin on the oxyntic glands in certain species [49], that is, sham feeding combined with intravenous infusions of low doses of gastrin produces acid responses in dogs after resection of the antrum and duodenal bulb [50]. Of particular conceptual importance, Knutson and Olbe [51] were unable to demonstrate this synergism in sham feeding experiments in duodenal ulcer patients after antrectomy. In these studies the sham feeding responses were not potentiated by threshold doses of exogenous gastrin. It is impossible at this time to understand clearly what effect residual innervation to the pyloric gland area has upon overall secretion of hydrochloric acid from the oxyntic glands in patients after parietal cell vagotomy. Suffice it to say that gastrin and cholinergic stimuli are markedly interdependent in stimulating gastric acid secretion. Removal of cholinergic tone by vagotomy depresses the response of oxyntic cells to gastrin and, indeed, to all stimuli for the secretion of acid. Thus, after parietal ceil vagotomy, the effect of physiologic levels of circulating gastrin from the innervated antrum upon the oxyntic glands is dampened and hopefully not of concern. Maher et al [52], in sham feeding experiments in the dog, also have noted a lack of correlation between elevated gastrin levels and increased acid output from Pavlov pouches. Their findings further demonstrate a lack of importance to the vagal release of gastrin. Many more studies must be undertaken before this matter is resolved. Gastric motility and the vagus: The continued active antral peristalsis seen by cinefluorography after parietal cell vagotomy is most impressive. Wilbur and Kelly [53] have demonstrated alterations of gastric emptying patterns after parietal cell vagotomy. They have separated the vagal factors related to gastric emptying into two parts, namely, the vagally innervated proximal stomach, which regulates the gastric emptying of liquids by controlling gastric transmural pressure, and the vagally innervated antrum, which regulates gastric emptying of solids by controlling the terminal antral contraction. ln dogs, they confirmed this thesis and found that parietal cell vagotomy disturbed gastric motility and emptying less than did

The American Journal of Surgery

selective or truncal gastric vagotomy. Although all three types of vagotomy increased gastric transmural pressure with gastric distention and hastened gastric emptying of liquids, only parietal cell vagotomy preserved the terminal antral contractions and did not slow gastric emptying of solids. Thus, parietal cell vagotomy, although not ideal, does retain an important portion of the gastric emptying complex, The rapid emptying of liquids, regardless of an intact pylorus, after parietal cell vagotomy may explain why patients after the procedure have complained of symptoms indicative of the “dumping syndrome.” Regeneration of the vagus nerves: As previously stated, surgeons have worked diligently to find ways to ascertain completeness of vagotomy to the total stomach, either by the truncal or selective technic. Murray [54] studied mechanisms whereby partial or incomplete vagotomy might allow reinnervation of the stomach. The trend to leave vagal innervation to the antrum intact suggests that these studies should be reviewed. Murray [55] summarized these observations concerning regeneration of the vagus. Basically, there are two causes for concern, regeneration across gaps and the phenomenon of sprouting. The classical regrowth of the divided end of the proximal fiber across the gap into the distal pathway is probably not germane to this discussion. However, sprouting of nerves may be pertinent. Murray indicates that, whenever there is a close intermingling of intact and degenerating nerve fibers, sprouting is inevitable. A humoral agent derived from adjacent degenerating fibers causes localized disorganization of the surface of adjoining normal fibers, followed by outgrowth of small exoplasmic strands. These minute strands grow and “are guided by the Schwann cells in the degenerating tubes so that the branches may reach appropriate endings” [55]. The findings of Johnston, et al (561 are also of interest. Within one year after parietal cell vagotomy, the positive Hollander rate in 100 insulin tests was 51 per cent as contrasted with a 3 per cent positive Hollander test one week after the operation. Does this striking observation represent evidence of nerve regeneration and/or sprouting? IS this finding of clinical importance? There are no answers to these questions at the moment. Three major areas of concern, vagal release of gastrin, gastric motility, and vagal regeneration or sprouting, have been reviewed within the context of the new operation for duodenal ulcer, parietal cell vagotomy, wherein the antrum remains vagally

Vo&mw131, JHIUUY 1076

innervated. In summary, vagal release of gastrin does not seem to seriously threaten effective decrease in acid secretion, gastric motility is less disturbed after parietal cell vagotomy, and vagal reinnervation of the proximal stomach remains an unknown factor. From these physiologic observations, is it possible to completely abandon the thirty-two year old concept that complete vagal denervation of the entire stomach is the sine qua non of a good duodenal ulcer operation? The answer appears to be weakly affirmative; however, we must continue to search for answers to the many obvious voids in our knowledge. The Clinical Record of Parietal Cell Vagotomy. The true worth of any safe operative procedure for the treatment of duodenal ulcer must be gauged against one and only one criterion, namely, does the operation cure the disease? It has been clearly demonstrated that surgeons do know technics that can assure an acceptable recurrent ulcer rate. It is of interest that one of these operations is subtotal gastrectomy, without vagotomy (61. As the various clinical reports of parietal cell vagotomy appear, the early record of excellence seems to be deteriorating. This is very disconcerting. The complex reasons for exceptional results on the one hand and unacceptable results on the other defy accurate analysis 157-63). (Table V.) Unfortunately, the largest series of patients with parietal cell vagotomy [59] was not compared with another standard procedure in a prospective, randomized fashion. Regardless, the recurrent ulcer rate of less than 1 per cent in these patients is impressive. Contrariwise, scattered reports (all prospective, randomized) have appeared that do not confirm that parietal cell vagotomy can be performed by every surgeon with impunity to the stigmata of recurrent ulcer in these patients [60,62]. The study of Kronborg and Madsen [62] is of particular interest. It began in 1970 and ended four years later and compared parietal cell vagotomy with selective vagotomy plus Heineke-Mikulicz pyloroplasty. Although the patients with the latter procedure were found to have a recurrent ulcer rate of 8 per cent, the recurrent and persisting ulcers in the one to four year follow-up after parietal cell vagotomy was 22 per cent. The immediate reaction to the increased risk for recurrence (8 per cent) after selective vagotomy and drainage is to suspect that the selective vagotomy was not performed well technically. It would follow, the high recurrent ulcer rate after parietal cell vagotomy was due to a poor technical operation by the authors. This assumption of lack of technical exper-

7

Nytws

TABLE V

Clinical Results of Parietal Cell Vagotomy for Duodenal Ulcer Number of Patients

Author Hedenstedt, Lundquist, and Moberg [57] Wastell, Wilson, and Pigott

[581* Amdrup et al [59] Bornbeck et al [ 60]* Grassi (611 Kronborg and Madsen Johnston

[ 62]*

52 271 30 85 50 4,557 (collected)

[63]

* Prospective,

131

Length of Follow-Up (vr)

Dumping

(severe)

Diarrhea

(severe)

Ulcer

(per cent)

Operative Mortality (per cent)

to 3

0

0

2.4

0

1 to 3

0

0

4

0

1 0 0 1

0 0 0 1

0 4 1 22

0 0 0 0

0.5

2 0.5 1 1

to 4 to 5 to4 to 4

...

Necrosis lesser gastric curve, 7 patients

Gastric retention (early), 30 patients

gastric stasis

0.26

(late), 29 patients

randomized.

tise is not valid. Kronborg and Madsen performed both PCV and SGV after the technic of Amdrup and Jensen [64]. In 1973, Amdrup [65] reported that the recurrent ulcer rate after selective vagotomy was 6 per cent in his clinic. Thus, the two groups of investigators had essentially identical results with selective gastric vagotomy, but disparate results with parietal cell vagotomy. I doubt that technical factors played a role in these studies. It is impossible to explain these differences, although the specter of inadvertent patient preselection always comes forward when randomization is not performed. Controversy is becoming more heated among protagonists and antagonists of parietal cell vagotomy relative to (1) the necessity for intraoperative testing for completeness of vagotomy; (2) the interpretation and actual meaning of the insulin test and gastrin levels in the postoperative period; and (3) the presence or absence of the “criminal nerve,” a major nerve trunk from the right posterior vagus that leaves the proximal main trunk to innervate the posterior gastric fundus [66]. The name given to this branch connotes difficulty in identification and, therefore, if not severed, it may be a common cause for incomplete vagotomy. A successful operative procedure for the treatment of duodenal ulcer must be relatively simple to perform with proven low operative and postoperative morbidity and mortality. In addition, the overall results must be satisfactory in the hands of all well trained surgeons. Parietal cell vagotomy is far from having reached the point wherein it can be called a “successful operative procedure for the treatment of duodenal ulcer.” Surgical history suggests that a period of twenty years is needed before a new operative technic for

8

Recurrent

duodenal ulcer finds its proper place in our list of approved procedures. Let us hope that we can find the answer relative to the efficacy of parietal cell vagotomy in the treatment of duodenal ulcer in a shorter interval of time. The advent of prospective, randomized studies in the surgical world should help us to find the answer much sooner. The Appllcatlon Gastrointestinal

of Mokcular Research

Blolcgy to

In April 1953, a short (one page) paper appeared in Nature with the title, “Molecular structure of nucleic acids: a structure of deoxyribonucleic acid” by Watson and Crick [67]. Although the authors, in a classic example of understatement, concluded their paper with the comment, “It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material,” there is no denying that this paper was the basis for an explosion of knowledge in the diverse area of molecular biology that occurred during the next twenty years. Now that the sciences of molecular and cellular biology have come of age, newer avenues in cellular and subcellular biochemistry have been explored, and innumerable sophisticated technics have been developed, it is appropriate that the focus in future gastrointestinal research be directed alongthese lines. There is no doubt that the newer concepts in gastrointestinal research will come from the laboratories of cellular biology. Neurobiologic

Studies

of the Gastric

Mucosa.

Recognizing the need for a new and fresh outlook in gastrointestinal research, we have directed a part of our research effort in the last few years to the cellular and subcellular morphologic and func-

lho American Journal ti Sugary

tional levels of the gastric mucosa. Although several types of investigation are in progress and details of methodology and results are being published elsewhere, I shall describe some of the results thus far obtained. Figure 1 shows a low power panoramic view of the fundic mucosa of the rodent stomach. The individual cell types, nerve fibers, and other components of the lamina propria are demonstrated. The nerve fibers contain axons originating in the myenteric and/or submucous plexi, or are a direct continuation of vagal fibers.’ One of the prime areas of interest to us has been a detailed morpho-

logic investigation of the neural types of control to cells and capillaries of the gastric mucosa. We have demonstrated that vagal fibers directly innervate the parietal cells in the fundic mucosa of the rodent stomach [68]. In Figures 2 and 3, the type of innervation is shown. The terminal axon contains both granular and agranular vesicles. From the morphologic study of other authors [69], it is reasonable to postulate that these axon terminals probably contain acetylcholine. The validity of the argument that some of these axon terminals are vagal in origin is substantiated by the fact that after truncal vagotomy these axons in contact with

Figure 2. In h&her -atrOn, IndMduai naked axon tennfnafe (Ax) bve been seen temdnatfng an tfm parfetal ce3 (PC) membrane, thus eetaf&Mtng tfm dkect fmwrvatfon of theae cefts. Portkms of another parteta/ ceft (PC), two xymogen ceffg (Zc,, endocrffle ceft C@C), emooth muscfe (SM), and a capMary (Cap) can be en. (Orfgfnal magnffftzatfon X 13,OpO.)

Volume 131,~anuafy 1976

9

Nyhus

Figure 3. Agranular

(acetykhoike?) and veskles are the content of these termlnais. The Intimate contact between axon (Ax) and the parietal cell (PC) is seen. Portkns of a zymogen cell (ZC) and of a capillary endothelki cell (End) are seen. (Original magnifkatkn X 44,000.)

granular (catecholamines?)

the parietal cell membranes undergo degeneration. (Figure 4.) Doctor Kalahanis, from our laboratory, is presenting to this Society detailed findings of the nerve supply to fundic vessels as well as the effect of vagotomy [70]. Although I do not want to dwell on this subject in any detail, it needs to be emphasized that the arteriole can be innervated directly. Figure 5 shows a cross section of an arteriole. The inner endothelial layer of the arteriolar wall is separated from the outer muscular layer (M) by the middle elastic layer (EL). Nerve fibers are seen in the adventitia, which are in contact with smooth muscles. Figure 6 shows the degenerating axon in contact with the endothelial wall of the capillary. This micrograph was taken six days after truncal vagotomy. These findings require corroboration by further investigation. There is no denial of the fact, however, that morphologic investigations of the microanatomy of the nerves in the fundic mucosa will lead to information hitherto unrecognized. One such future investigation might be to study the status of axons long after vagotomy has been performed, to establish whether the fibers remain degenerated, or tend to regenerate. If they do tend to regenerate, after what interval? Do the axons actually reinnervate the target cells, or do the target cells have other sources of excitatory and inhibitory impulses?

10

Transport Systems in the Gastric Mucosa. Another area requiring investigation is the transport system of the various inorganic particles important to the process of gastric function. For example, Das Gupta, Moss, and Newson [71] modified the technic of Kominick and Kominick [72] and developed a technic of ultrastructural localization of sodium in the extracellular space in the primate lung. Applying a similar technic in the rodent stomach, we have recently reported on the localization of sodium in the extracellular space of the stomach mucosa [73]. In Figure 7 the clumps of sodium pyroantimony deposits are seen in and around the collagen fibers in the interstitium. In the normal control rodent stomach, this clumping of sodium around the collagen fibers constitutes a consistent finding. However, in the pentagastrinstimulated stomach mucosa, the distribution of sodium pyroantimony is changed. In Figure 8, it is noted that there is a trend to concentration of the sodium on the plasma membrane, the intercellular clefts, and the pinocytotic vesicles of the capillary endothelium. Although sodium is still seen in the collagen matrix, the extent of localization is considerably reduced. In contrast, in the secretin-inhibited mucosa there is a general diminution of the reaction product. (Figure 9.) Sodium is generally accepted as one of the main ions in the interstitial space. The significance of this ion for the function of the epithelial cells of

The American Journal

of Surgery

Pm&dent&l Address

Flgwe 4. Micrograph taken seven days after vagotomy. Hease note the live axons part/al& covered by Schwann cell cytoplasm (SC). Axon @ax,) tnnervatlng the parletal cell (PC), and axon (DAxs) are degenerated, whereas the remaining three axtons (Ax) look normal. For&n of a capillaq iEsseen to the IetY ot the mkrograph. (Ortglnal magnfflcation X 25,000.)

Figure 5. lhls ls a cross section of an arteriole. The Inner eqdothellal layer (End) of the arteriolar wall ls separated from the outer musc&r layer (M) by the mhldle elastic (el) layer. Two nerve bundles (NF) are seen In the adventMa. Axons (Ax,, Ax*, and Ax,) are respectively In contact wlth the smooth muscles (M,, &, and 4) of the arterlolar wall. (Orlglnal magn#lcatlon X &?,OOO.)

Figure 6. This micrograph ls from an animal four days affer vegotomy. 7’he narrow space between the capltiary (Cap) and the xymogen cell (ZC) ls occupted by two &genera& ed axon term&&s. Axon @Ax,) is lnnervating the endothehl cell (End) of the capMary wall, whereas axon (DAxs) lnnervatlng ts ths Fymogen cell. RBC = red bland cell. (Orlginal magnlflcatlon X 10,000.)

Vohme 131, January 1976

11

Nyhus

Figure 7. Area from the lamlna proprla of the gastrk mucosa from a control aneal. Portkns of a capillary (Cap), a par/eta/ cell (PC), and a smooth muscle (SM) are seen. The sodium pyroantlmony crystals (arrows) are seen in and around the collagen fiber (Co) In the form of large clumps. Per = perkyte. (Original magnlfkatkn X 30,000.)

Figure 8. Mkrograph frOm a pentagastdn-stlmulated gas&k mucosa. Rwtkns of a few epRhel/al cefls (EpC) and of smooth muscle (SM) are seen. The reactkn product Is seen (arrows) In the plasma membranes and the lntercelklar clefis of the epltheliai celk, whereas in the collagen fibers (Co) the reactkn is seen ln the form of smaN gkbules. (OrigInal magntfkatkn X 30,000.)

the gastric mucosa has been extensively discussed and it is known to be one of the electrolytes of the gastric juice. However, there are differences of opinion as to whether sodium actually participates in the active process of ion exchange across the cell membrane; and even if it does take part in the transport system, the direction of the flow during the excitatory phase of the cell has never been ascertained. Using the sodium pyroantimony mark-

12

er, we have observed that in the pentagastrinstimulated mucosa, sodium ions take part in ion transport and are taken across the endothelial lining of the capillary by means of pinocytosis, an established biological active process. These electron histochemical findings obviously require tissue biochemical corroboration and interpretation. However, it is logical to propose that application of these technics might dispel some of

Tha Amafkan

Journalof Surgary

PresidentialAddress

F&we tk Mkmgraph from secrettn tnhbtted @wrk mwosa,

Pti wh co&w fbm WI. lRe sodhnn crystab (arrows) are we18 on& b and around the colvagen f&em and h kas amount than in the ofh8r two w. (Ormai magntfkatton X 20,000.)

the mystery surrounding transport in the gastric physiologic conditions.

the mechanism of ion mucosa under varying

Neurosecretion and Gastric Physiology For the sake of clarity, I am terming another area of investigation in which we are presently involved “neurosecretion and gastric physiology.” One of the most fascinating aspects of gastric research in the future will be the elucidation of the role of neurosecretion vis-a-vis mammalian stomach function. However, before I present our views on the role of neurosecretion in the stomach, it is appropriate to review briefly the history of the concept of neurosecretion. Carl Spiedel in 1919 first coined the term glandub nerve in the elasmobranchs [74]. Scharrer [75] described similar nerve cells in vertebrates in the 1920s. After a hiatus of about twenty-five years, Palay [76] and Bargmann, Hanstrom, and Scharrer [ 771 described secretory-appearing neurons in the vertebrate hypothalamus, which were traced reaching to the neurohypophysis. Harris [78] at the same time independently elaborated on the nature of the humoral control of the mammalian hypophysis cerebri. During the next decade, the then revolutionary concept of a regulatory hypothalamohypophyseal system in vertebrates was developed. Simulta-

vobmn 131. January 1876

neously the term “neurohemal” organ was coined by Knowles [79], resulting in a variety of expressions meaning the same entity. However, after considerable discussion the term “neurosecretion” was accepted as representing a unified concept. The classic definition of neurosecretion is based on demonstration by standard cytologic methods at the light microscopic level, of glandular activity, characterized by the localization of secretory granules, either with chrome-alum hematoxylin or paraldehyde fuchsin, as developed by Gomori and Pearse [80]. Since then, more sophisticated staining technics have been developed. Application of electron microscopy further defined cytologic criteria that would be employed in delineating the neurosecretory neuron. The description by Bargmann [81], Palay [82], and many others of electron-dense granules in the 1,000 to 3,000 A range in the neurohypohysis of vertebrates were landmark observations. Further, the finding of similar granules in the urohypophysis of the caudal neurosecretory system of fishes and in the neurohemal organs of many invertebrates gave rise to the hope that the occurrence of such granules in the axon terminals would conclusively indicate the presence of neurosecretory material. The primary role of neurosecretion has always been considered to be hormonogenesis. The hormone produced by neurosecretory cells may act at the periphery to regulate various aspects of the

13

Nyhus

conveying of nervous information

(I

i a:

w

Figure 10. Dtagrammatic representation of synthesis and storage of neurosecretory material In a neurosecretory cell. The endoplasmk retkuhsn offers the material to the Golgi apparatus, which In turn stores this material In ehsmentary granules. (From [83]. Reproduced with permission of the publtsher.) Lower letl diagram represents the appearance of electron-dense material within Golgi lamellae and the format&n oi membrane l&Wed granules by buddlng and veskulation. Lower right diagram represents iormatkn of electron-kcent vesicles and their sub&quent transformatkn into electron-dense granules. (From Gem HA: 7% secretory neuron as a duubty spectathd cett. The General Physkkgy of Cell Specialtzat/on (Maria D, Tyler A, ed). New York, McGraw-Hill, pp 349-366. Reproduced with permission ot McGraw-Hill Book Compeny.)

physiology of the organism. However, there are other neurohormones that are distributed by vascular channels but do not act directly on nonendocrine target tissue; instead, they exert a trophic action upon other endocrine glands. Although all the intricacies of the role of neurosecretion or neurosecretory hormone have not yet been properly elucidated, it is generally agreed that the common denominator of all neurosecretory cells derived from the concept thus far developed is neither morphologic nor biochemical but lies in the role of these cells as the last link in the chain uniting the nervous and endocrine systems. In one of several possible ways, the neurosecretory hormone probably represents the final common pathway for the

14

to the endocrine

system. The prevailing consensus is that the neurosecretory cell is a specialized neuron (therefore of neuroectodermal origin) in which the ability to secrete has become extensively developed and of primary importance. Because of this specialized development, these cells can be characterized as glandular cells with intracytoplasmic granular vesicles, well developed endoplasmic reticula, and prominent Golgi zones. The cell membrane has been found in contact with the basement membrane through which it diffuses its discharge of hormonal product. Figure 10 represents a diagrammatic rendition of presumed synthesis of neurosecretory material in such a cell, as proposed by Scharrer and Brown [83]. A detailed discussion of all the morphologic aspects of a neurosecretory neuron is not germane to our thesis. It suffices to emphasize that enough data are available to conclude that by a process of specialized evolution of neuroectodermal cells within the same central nervous system, these specialized cells are capable of active synthesis of hormones as are other glandular cells. Fortunately for the gastric physiologist, the research has moved beyond the classic definitions of the nervous system. With the description by Pearse [84] of the APUD (amine precursor uptake and decarboxylation) system in thyroid and ultimobranchial C cells, and ultimate demonstration of such cells in the upper gastrointestinal tract, a new dimension to neuroendocrinologic research in the gastrointestinal tract has been added. In this concept, the cells of embryonal gut origin (including the C cells of the thyroid, the alpha and beta cells of the pancreatic islet, the anterior pituitary cells, and the enterochromaffin cells in the gastrointestinal tract and in the exocrine glands) are capable of formation and accumulation of amines together with a polypeptide secretory product. We have directed our attention to the study of “enterochromaffin-like cells” in the fundic mucosa of the rodent stomach. We have been able to demonstrate the presence of a type of cell that has all the morphologic characteristics of an enterochromaffin cell. (Figure 11.) The details of tissue preparation, fixation, and other technical aspects will be published elsewhere. This represents a view of the cytoplasm of such a cell. The most spectacular finding in these cells is the presence of large cytoplasmic vacuoles containing an eccentrically situated dense core. This finding is reminiscent of the secretory granules seen in classic neurosecretory

The American Journal of Surgery

F@re 11. A portton of the cytoplasm of an enhwoctim-We cett (ECL) from a contrd anhal. 77be matn uttrastructural feature of these endocdne cd& are the large cytopIaamk vacwhs twntabhg an eccentdcaliy sthded denee cafe. our ptNmec~o@c at&es hav4 shown that these gram&s contain catechotamtnes. Portions of two zynwgen cetts (ZC) 810 seen. (Original magnifkath X 16,000.)

F&we 72. Electran mkrograph from gaetdc nntcosa treated accad@ to CoupIand and Hopwood techdc for staining of catecholemines. An entemchnnafh?-like cet/ (ECL) ts seen ad&went to three zymogen ceMs (ZC). f&Me the catecholamh reaction h the fom9 of dense granhs In the cytoplaem of thfs ceN. Some reaction can be seen In the interstltknn adjacent to the plasma membrane of the cell. (Original magnification X 5,000.)

cells. Furthermore, by using the technics of ultrastructural localization of biogenic amines developed by Coupland and Hopwood [85], we have found that these cells contain biogenic amines (catecholamines, serotonin). (Figure 12.) We have also observed that the cytoplasm of these cells can be depleted of these granules when treated with specific biogenic amine inhibitors (tyrosine hydroxylase inhibitor). Therefore, it is valid to assume that the cells we are observing and describing are the enterochromaffin-like cells (EC) also observed by Polak, Pearse, and Heath [86]. The most startling observation was the depletion of these biogenic amine-containing granules

Vohana 131, January 1976

from the cytoplasm of the enterochromaffin cells after total truncal vagotomy. (Figure 13.) This depletion of granules has been a consistent finding and it is noteworthy that no other organelle within the cytoplasm was affected. In some instances we observed that these granules were in the process of extrusion out of the cell by means of reverse pinocytosis. Therefore, it is logical to assume that after vagotomy, by means of an active biologic process, the biogenic amines leave the barrier of their storage site within the enterochromaffin cell cytoplasm and affect a target cell or a group of target cells locally and/or reach the circulation entering through the adjacent capillary endothelial lining

15

Nyhus

Figure 13. Mkrograph taken six days after vagotomy. it shows the depletion of the gram&s from two enterochromaffin-like ceils (ECL) without any other changes in the cytopiasm. 77wee zymogen ceils (ZC) are seen in this mkrograph, adjacent to the enterochromaffin-like ceik. (Original magnification X g,OOO.)

--

-_--

Figure 14. Conceptual diagram proposed for the possible role of the enterochromaffin-like ceil (ECL) in gastric secret&n. BrOgenic amines (BA), liberated from these ceils aHer a stimulus (vagus, food) act, either directly or indirectly through the hypothaiamoneurohypophysiai system on the gasiric glandular ceik (parietai ceii, PC; endocrine ceuS, EC), thus modulating their hmctlon.

by pinocytosis in a manner similar to that of sodium pyroantimony crystals. The pharmacomorphologic observations presented herein, therefore, allow us justifiably to consider the enterochromaffin-like cells in the rodent gastric mucosa as neurosecretory cells liber-

16

ating neurosecretory hormones (biogenic amines), which in turn actually play an important role in gastric secretion. The inevitable question after such an exhaustive preamble on the characterization and functioning of a cell in the fundic mucosa is, What is its true role? It is obvious I do not have all the answers, because all the parts of this puzzle are not available. However, for the sake of discussion I would like to propose a tentative hypothesis, which will try to place the operational aspects of the enterochromaffin-like cell in proper perspective, relative to the complex process of production of “gastric thyme.” Let us assume that enterochromaffin-like cells are either directly stimulated by secretogogues in the stomach or by vagal impulses. This in turn releases the intracytoplasmic biogenic amines out of the cell. By some hitherto unexplained mechanism, these amines then act on the cell membrane of the neighboring cells. For example, these amines could also act through an intermediary on the parietal cell and influence its function, or on the endocrine cells to produce one or more types of hormones. Finally, some of these amines, by the process of pinocytosis, may enter the systemic circulation and initiate a “braking” mechanism in the production of gastric secretion. Figure 14 describes this tentative hypothesis. It must be emphasized that this is a conceptual diagram and requires further investigation to corroborate or to propose a new role for these neurosecretory cells in the mammalian stomach. I am confident that in days to come, other investigators will delve into the problems I have alluded to and will arrive at more definitive conclusions.

The American Journal of Surgery

President&l Adc@as

My main objective in this presentation is to stimulate the surgical gastroenterologist to direct his research potential along a path that, for reasons not known, has been followed insufficiently in the past. Human biology is a complex phenomenon. Enormous amounts of information are involved in the control of living organisms. If we assume 2,000 letters to a page, then the molecular description for a viron would occupy a book of 100 pages (2 X 105 nucleotide pairs), those for a bacterium, a book of 2,500 pages (5 X 10s pairs), and those for man 1,700 books of 1,000 pages each (3.5 X 109). This gives us some idea of the tremendous complexity of life and also warns us against trying always to look for a simplistic answer to all of our questions,. be it in the field of human genetics or gastric physiology. Throughout this part of the presentation I have offered my thoughts on the probable direction of future research in control mechanisms, both stimulatory or inhibitory, of gastric secretion. It seems that unless all these newer avenues are explored fully, we will arrive at an intellectual impasse. If my overview of our research program has stimulated you to think along these lines, I shall consider my presentation a success. References 1. Latarjet A: Resection des nerfs de I’estomac. Technique operatoire. Resultats cliniques. 8uU Acad Neti A&d (Paris) 87: 681, 1922. 2. Drag&& LR, Owens FM Jr: Supadiiphragmatic section of the vagus nerves h the treatment of duodenal ulcer. PToc SocExpBiolMed53: 152, 1943. 3. Lynch JD, Jemigan SK,.Trotta PH. Clemens BE: lnckfence and analysis of faifure with vagotorny and Haineke-MYtu licz pykroplasty. Swgery 58: 483.1965. 4. Nob& ER jr: V&pto& and gastroenterostomy: 15 year follow-u0 of 175 oatients. Am Sum 32: 177, 1966. 5. Bryant WM, Klein D. Griffen WO Jr:?he role of vagotomy in duodenal uker svgery. Suqery61: 864. 1967. FT. Conyefs JH, Du6. Golm JC, P~&ertaft CN, de&r&al thie HL, Feather DB, Latchmore AX, Harrop-Shoesmith J. Smktdy FG. Willison-PepOer J: Fiisto-eight year results of Leeds/York controlled trial of elective surgery for duode&ulcer. 8rMedJ2: 781, 1968. 7. Stempkn SJ. Dagadi AE. Lee ER. Simonton JH: Status of duodenal ulcer patients ten years or mo(e after vagotcmy-phbroplasty (V-P). Gestroenterchgy 58: 997, 1970. 8. Kronborg 0: Truncal vagotomy and drainage in 500 patients with duodenal ulcer. ScandJGsstroenh~d6: 501.1971. 9. Hoen SO, Ward JT: Late results of three operations for chronic duodenal ulcer: vagotomy-gastrojejunostomy, vavagotomy-pyloroplasty. Ann gotomy*igastrectomy, Swg 176: 403.1974. 10. Howard RJ. Murphy WI?, Humphrey EW: A prospective randcmhed study of the elective surgical treatment for duodenal ulcer: two-to-ten year follow-up study. Swgery 73: 256, 1973. 11. Kennedy T. Connell AM. Love AHG, Ma&e KD. Spencer EFA: Sekctive or trunr~l vagotomy? Five-year resufts of a double-blind, randomized. contrdled trial. Br J Swg 60: 944, 1973.

VoUln 131. JMUUY 1970

12. Dragstedt LR Il. Lulu RI: Truncal vagotorny and py@oplasty. CritIcal evaluation of cne hundred cases. Am J Sug 128: 344, 1974. 13. Nyhw LM, Conddn RE, Harkins I+& The evolutkm of sugery for duodenal ulcer dubrg the mid-twentieth century. J R CoNSurg E/n&b 8: 91, 1963. 14. Farmer DA, Harrower HW, Smithwick RH: The chdce of SUTgery in peptic ulcer dkease. Am J Swg 120: 295, 1970. 15. Bergar T, Kock NG, Norberg PB: Truncal vagotorny with “antrectomy” or pyloropjasty for dundmal ulcer. Acte CM Sand 138: 499, 1972. 16. Svensson A: Vagotomy with antrum resection. Acta Chk scant-l 140: 50, 1974. 17. Johnson FE, Boyden EA: The effect of dctubb vagotomy on the motor activity of the human @ bladder. Surgery 32: 591,1952. 18. Rudick J, Hutchinsan JSF: Effects of vagal nerve sectbn on the biliary system. Lencef 1: 579, 1964. 19. Glanville JN, Duthia HL: Contra& of the gallbladder before and after total abdominal vagotomy. C& Radkll5: 350, 1964. 20. Fletcher DM, Clark CG: Changes in canine bile-Row and compostin after vagotomy. 8r J Surg 56: 103. 1969. 21. Fields M, Duthie HL: Effect of vagotomy on intraluminal digsstbn of fat in man. Gut 6: 301, 1965. 22. Cowie AGA. Clark CG: Tha lithogenic effect of vagotomy. Br J Swg 59: 365, 1972. 23. Tompkins RK, Kraft AR, Zimmerman E, menstein JE, Zollinger RM: Clinical and biochemical evidence of increased gallstone formatbn after complete vagotomy. Surgery 7 1: 196, 1972. 24. Dreillng DA, Druckarman LJ, HoUander F: The effect of complete vagisection and vagal stimu&tion on pancreatic secretion in man. Gastrcwnhwobgy 20: 578. 1952. 25. Thambugala RK, Baron JH: Pancreatic secretbn after selactive and truncal vagotomy in the dog. Br J Swg 58: 839, 1971. 26. Russell RCG, Thomson JPS, Bloom SR: The effect of truncal and selective vagotomy on the rebfu3e of pancmatlc 9b capon, insulin and enteroglucagon. Br J Surg 61: 821. 1974. 27. Alvarez WC, Hasei K, Dvergaard A, Ascanb H: The effects of degenerative section of the vagi and the splanchnics on the digestive tract. Am J Fhysbl90: 631.1929. 28. Balllnger WF: The extragastric effects of vagotomy. Surg Cl/n North Am 46: 455, 1966. 29. Baldwin JN, Albo R, Jaffe B, Silen W: Metabolic effects of selective and total vagotomy. Swg Gyneco/ Obstet 120: 777, 1965. 30. Ballinger WF Il. lida J, Pad& RT, Aponte (Y. W.& CW. Gokfstein F: Bacterial inftammation and denervatbnatrophy of the small iiltesttne. sfqery 57: 535.1965. 31. Yamagishi M, Dhkubo T. Kasakawa T, Endo S, Kobayashi M, Kobayashi T, Yashimura Y, Hashimoto S: ExperImental studies on hemigastrectomy combined with vagotomy: a comparison of total truncal and selective gastrk vagotomy. Rev Sug 22: 402. 1965. 32. Elliot RL, Barnett WO, EtUott RC: An ultrastructural study of the smatl intestlna after vagotomy. Sug GynecoI Cbstet 124: 1037. 1967. 33. Cox AG: Small intestine absorption before and after vagotomy in man. &ancet 2: 1075. 1962. 34. Wastell C, EHk H: Faecal fat excretion and stool co&ur after vagotomy and pybroplasty. Br Med J 1: 1194, 1966. 35. QrifRth CA, Harkins HN: Partial gastric vagotomy: an experimental study. Gastroentwubgy 32: 96, 1957. 36. Fujino R: Consequences of sdectfve proxbnal vagotomy in biliary tract pathology. Jap J Surg 4: 104,1974. 37. Parkin GJS, Smith RB. Johnston D: Gettbladder volwne and contractility after truncal. &active and hlgh!y selective (par&al cell) vagotomy in man. Ann Swg 178: 581, 1973. 38. McKeivey STD. Toner D. Connell AM. Kennedy TLz CoeYac

I?

and hepatk nerve function tdlowkg sekctfve vagotomy. Br J Surg60: 219, 1973. 39. ENtrwr R. Beger HG, Kraas E. Roscher R: Glucose tolerance and ksufln secretion after selective vagotomy and pykroplasty. Br J Surg 62: 153, 1975. 40. Kennedy T: Sekctive vagotomy. Chronic Duodenal Ulcer (Waste8 C, ed). Lc&m, Butterworth. 1974. 41. Harklns HN, Stavney LS. &ffffth CA, Savage LE. Kato T, Nyhus LM: selective gastric vagotomy. Ann Surg 158: 448, 1863. 42. Kennedy T, Connefl AM. Love AHG, MacRae KD, Spencer EFA: Sekctfve or truncal vagotomy? Five-year results of a double-blind, randomized, contrdfed trial. Br J Surg 60: 944,1973. 43. Sawyers JL. Scott HW Jr: Selective gastrk vagotomy with antrectcmy cr pykroplasty. Ann Surg 174: 54 1, 197 1. 44. Sawyers JL: Personal communication. 45. Holle F: Form- und funktknsgerechtes operieren. Disk. 41 Tagg. Bayer. Chir Vereingung Miinchan. 1964. 46. Nyhus LM: The role of the antrum in the surgical treatment of peptic ulcer. GWroenterology 38: 2 1, 1960. 47. Pevsner L, Grossman MI: The meciiantsm of vagal stimulatkn of gastric acid secretion. GastroenteroIogy 28: 493, 1955. 48. Dfbe L: Effect of resection of gastrin releasing regions on acid response to sham feeding and insulin hypoglycemia in Pavkv pouch dogs. Acta physbl Scat& 62: 169. 1964. 49. UvnPs B: The part played by the pykrk region in the cephafk phase of gastric secretion. Acta Pnyaio/ &and 4 (Suppl XB). 1942. 50. S)odin L: The potency of gastrin and related peptides to enhance the gastric secretory response to sham feeding. Scarxl J Gastroentwol7: 145. 1972. 5 1. Knutson U, Dfbe L: Signifkance of the antrum in gastric acid response to sham feeding in duodenal uker patients. In Gastrointestinal Hormones and Dther Subjects. Copenhagen, Munksgaard, 1971. 52. Maher JW. Wkkbcm G. Woodward ER. McGuigan JE. Dragstedt LFi: The effect of vagal stimufation on gastrin release and acid secretion. Surgery 77: 255, 1975. 53. Wilbur BG, Kelfy KA: Effect of proximal gas&k, cornpkte gastrk. and buncal vagotomy on canine gastric e&k activity, motifby and emptying. Ann Surg 178: 295. 1973. 54. Murray G: Sprouting of nerves: some consequences of vagotomy and sympathectomy. Gastroenterokqy 42: 197. 1962. 55. Murray G Regeneration of the vagus nerves. Surgery of the Stomach and Duodenum, 2nd ed (Harkins HN. Nyhus LM, ed). Boston, Little, Brown, 1969. 56. Johnston D, Wifkinson AR, Humphrey CS. Smith RB, Go@her JC. Kragelund E. Amdrup E: Serial studies of gastric secretion in pabents after highly sekcttve (parietal celt) vagotomy without drainage ‘procedure for duodenal ulcer II. The insutfntest after hi@& selective vagotomy. GastroenteroIogy64: 12.1973. 57. Hedsnstedt S, Lundquist G, Moberg S: Selective proximal vagotomy (SPV) in the treatment of dudoenal ulcer. Acta CMScind 138: 591, 1972. 58. Waste5 C. Wlkon T, Pigott f-l: Proximal gastric vagotomy. RocRSocMed67: 1183. 1974. 59. Anxfnrp E. Jensen HE, Johnston 0, Walker BE, Goligher X: Clinical results of par&al cell vagotomy (hi seiective vagotomy) two to four years after operation. Ann Surg 180: 279. 1974. 60. Bombedr CT, Condon RE, Miller B. Nyhus LM: Vagotomy: a prospective, randomized study. Surg Forum 25: 327. 1974. 61. Grassl G: Vagotomk e ultrase4atttva 0 sefettiva prassimate. In chfrurgk dew0 stomaco e del duodeno (Harkins HN, Nyhus LM. ed). Padova, Plccin Editore. 1975.

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62. Kronborg 0. Madsen P: A contrdfed. randomized trial of highly sekctive vagotomy versus selectfve vagotomy and pykropfasty in the treatment of duodenal uker. Gut 16: 268,1975. 63. Johnston D: Operative mortafity and postoperative morbidity of highly selective vagotomy. Br J Surg 62: 160, 1975. 64. Am&up E. Jensen HE: selective vagotomy of the part&al cell mass preservkg innervation of the undrained antrum. Gastroenterobgy 59: 522. 1970. 65. Anxlrup E: Vagotcmy in the treatment of peptic ulcer. C/in Gastroenterot 2: 397, 1973. 66. Gressl G: Personal communicatkn. 67. Watson JD, Crick F: Molecular structure of nudeic acids: structure for deoxyribose nucleic acid. Natwe 171: 737, 1953. 68. Kaiahanis NG, Nyhus LM, Das Gupta TK: Morphokgk evidence of direct innervatkn of parktal cells in rodent gastric mucosa. Swg Forum 25: 333, 1974. 69. Peters A. Palay SL, Webster H: The Fine Structure of the Nervous System. New York, Hoeber Medical. 1970. 70. Kalahanis NG, Nyhus LM. Das Gupta TK: Neural control of bkod flow in gastric mucosa. Am J Surg 131: 1976. 71. Das Gupta TK, Moss GS, Newson B: Localization of sodium ion in the normal primate lung. Acta Anat 80: 426. 197 1. 72. Komnkk J, Komnkk V: ElektronenmYtroskopische Untersuchungen zur funktknellen Morphokgk des bnentranspcrtes In der Safzdruse von Lars argentatus. Z Zeyforsch A&rosk Anat60: 163, 1963. 73. Kafahanis NG. Das Gupta TK. Nyhus LM: Sodiim locatizatkn in normal, pentagastrkstimulated and secretin-inhibited rat gastric mucosa. Fed Proc 34: 453, 1975. 74. Bern HA, Knowles GW: Neurosecretkn, p 139. Neuroendocrinokgy (Martini L. Ganong WF. ed). New York, Academic Press, 1966. 75. Scharrer B: Hormones in invertebrates. p 57. The Hcmrones (Incus G. Thhann KV. ed). New York, Academic Press, 1955. 76. Palay SL: Neurosecretion VII. Ths preoptko-hypophysial pathway In tlshes. J Comp hburol82: 129. 1945. 77. Bargmann W, Hanstrorn B. Scharrer E: II lnternatknefes Symposium uber Neurosekretion. Berlin. Springer. 1958. 78. Harris GW: Central control of pituitary secretion, section 1. vd 2, p 1,007. Handbook of Physbfogy (Field J. ed). Battimore, Williams and Wilkins, 1960. 79. Knowles FG: The interrelation of secretory and nervous tunctbn in the central nervous system of lower animals, p 3. In Comparative Neurochemistry (Richter D, ed). Oxford, Pergamon Press, 1955. 80. Gomori G. Pearse AF: Histochemistry, Theoretical and Ap plied. London, Churchill Liiingstone, 1960. 81. Bargmann W: The neurosecretory system of the diencephabn. frt&avour 19: 125.1960. 82. Pafay DL: The Rne structure of neurohypophysis. p 3 1. Uttrastructure and Cellufar Chemistry of Neural Tissue (Waelsch H. ed). New York. Harper, 1957. 83. Scharrer E. Brown S: Neurosecretion lwbrkus in terristrk. Gen Comp Enbcrhol2: 2, 1963. 84. Pearse AG: Common cytochemical and ultrastructural characteristics of cells producing potypeptke hormones (The AWD Series) and thew relevance to thyroid and uftimobranchiil C cells and cakitonin. Proc R Sot B/o/ 170: 71, 1968. 85. Coupland RE. Hopwood D: The mechanism of the differential staining reaction for adrenaline and noradrenaline staining granuks in tissues fixed in glutarakfehyde. J Anet 100: 227, 1966. 86. Pofak JM, Pearse AF, Heath CM: Complete identlfkatbn of endocrine cells in the gastrointestinal tract using semithinthin sections to kentlfy motilin cells in human and animal intestine. Gut 16: 225. 1975.

lha Amofkan Journal

of Sugary