980
(ng/ml) of 5-H.I.A.A. to the concentration of probenecid (fLg/ml) was 7.46+1.64 (n=6). This compares with 10-8±2.3 (n=5) (P>0.05) in patients with normal hepatic function. These results suggest that elevated baseline levels of 5-H.I.A.A. may not indicate an increased turnover ofc.N.s. 5-H.T. All our patients were out of coma at the time of the second lumbar puncture. We have since obtained data from a patient with marked portosystemic shunting of blood through collateral vessels who was in stage 5+ to 6+ hepatic coma before receiving probenecid and 6+ at the termination; the ratio of increase in 5-H.I.A.A. to concentration of probenecid was 8.3. This would indicate that C.N.S. turnover is unchanged in hepatic coma. These results suggest that altered tryptophan metabolism has little if any role in the aetiology of hepatic coma in cirrhotic
patients.
SIR,-I read with pleasure, and agreed with, much of Professor Alberti’s letter (Oct. 25, p. 820). As he says, it would indeed be simple to calculate osmolality if, as is often incorrectly implied, SI terminology stated that the units mosmol and mmol are interchangeable. Alas, it would also be wrong. Plasma and other biological fluids are complex non-ideal "solutions". If we want to know their osmolality it is still necessary to measure it. But that is another story. Department of Clinical Biochemistry, Royal Victoria Infirmary, Newcastle upon Tyne NE1 7RU.
SIR,-In the beginning we were conned by the jingoistic jargon of the innovators who
Laboratory of Neurochemistry,
Department of Psychiatry,
SAMARTHJI LAL
McGill University, 1033 Pine Avenue West,
SIMON N. YOUNG THEODORE L. SOURKES
Montreal, Quebec, Canada.
HBsAG SUBTYPES IN FULMINANT
HEPATITIS
SiR,-Hepatitis-B surface antigen (HBsAg) subtypes have been determined in 25 patients with fulminant type-B hepatitis from various parts of the United States. The patients had been enrolled in a cooperative prospective study of the effect of hepatitis-B immune globulin conducted by the acute-hepaticfailure study group of the American Association for the Study of Liver Disease.’ Serum specimens were provided with the consent of the participating physicians and Dr James W. Mosley, the project coordinator. Most specimens were subtyped by a double-antibody radioimmunoassay (R.LA.) method2capable of identifying the d, y,3 and g2 determinants of HBsAg. Two specimens whose serotypes could not be conclusively defined by this method were typed by a more sensitive technique based on the specimen’s absorption pattern for monospecific, anti-HBs d, y, and g antisera, using a commercial solid-phase anti-HBs R.I.A. (’Ausab’, Abbott Laboratories, Chicago) for detection of the unabsorbed antisera.4 The overall results were as follows:
adg(+) 10, adg(-) 1, ayg(+) 0, ayg(-) 14. Sera from 105 patients with uncomplicated acute hepatitis B from the Dallas area were subtyped previously ;2 42 were adg(+), 0 adg(-), 3 ayg(+), and 60 ayg(-). Although rigid comparision of the fulminant-hepatitis and uncomplicated-hepatitis-groups is unjustified because of the different origins of the populations, the data suggest no special propensity of a given viral subtype to produce the fulminant form of hepatitis. Department of Internal Medicine, Dallas Veterans Administration Hospital and University of Texas Southwestern Medical School, Dallas, Texas, U.S.A.
JAMES SHOREY SI UNITS
SIR,-Dr Clark and Dr Sheldon (Oct. 11, p. 700) state that the D.H.S.S. issued a Diktat "without consultation, discussion, approval, or consent". The document prepared by the working-party was sent for comment in draft form (in August, 1973) by the D.H.S.S. to 37 organisations. All replied, most made useful suggestions that were incorporated in the final document, none castigated the proposals or suggested waiting five more vears. Department of Chemical Pathology, Royal Free Hospital, Pond Street, London NW3 2QG.
D. N. BARON
so swiftly and brutally foisted those wretched SI units on us. We have now had time to appreciate the preposterously unwieldy scales of normal values, and the dangerously blurred areas beyond the "normal" limits. In the name of commonsense, let us have done with this arrant nonsense and return, while we still can, to the "old" system that was long tried and trusted, and which our English-speaking colleagues in the U.S.A. show no signs of abandoning. Were we to have a referendum within the profession as to whether or not we ought to stay with SI units, an overwhelming majority would vote to "come out" and to return to sanity. Meanwhile, I suppose the regular arithmetical gymnastics involved in translating back to the sensible values are good for the mind.
Burghmuir Hospital, Perth, Scotland.
SIR,-Myocardial preservation during open-heart surgery remains a major problem. Recently the method of pericardial cooling introduced by Shumway’s group1 has been gaining wide acceptance, because of both its simplicity and its good results. One of the most sensitive methods of detecting myocardial injury has been the ’study of histochemical changes of the myocardial tissue, and several groups of workers have correlated the clinical outcome after open-heart surgery with the histochemical assessment of myocardial dysfunction during surgery.2-4 This method, however, has not been used to examine the effects of local cooling on the myocardium. In collaboration with the department of biochemistry of the cardiothoracic unit at St. Thomas’s Hospital, London, I have used this method in 19 cases of mitral and aortic valve replacement. Samples of the left ventricular wall were obtained with a pneumatic-drill biopsy at the beginning and at the end of the bypass period. The samples were immediately cooled and examined for acid haematein, succinodehydrogenase, A. T.P .ase, monoamine oxidase, cytochrome oxidase, and birefringence in the relaxed and contracted state. Changes were classified according to the following scale: 0=good, 1=fairly good, 1-2=moderate, 2=poor, and 3 =bad. The total score of each biopsy at the beginning of the operation was compared with that of the biopsy at the end of the operation. An increase in the score indicated myocardial deterioration. Only in 3 out of 19 cases was there such a deterioration, and in all these the operation had had to be extended to over 70 minutes. This finding 1. 2.
Hepatic Failure Study Group. Gastroenterology, 1974, 66, 752 (abstract). Shorey, J. J. infect. Dis. (in the press). Le Bouvier, G. L. ibid. 1971, 123, 671. Shorey, J. Unpublished.
R. G. SIMPSON
MYOCARDIAL CELL INJURY DURING OPEN-HEART SURGERY
1. Acute 2. 3. 4.
C. T. G. FLEAR
3. 4.
Griepp, R. B., Stinson, E. B., Shumway, N. E. J. thorac. cardiovasc. Surg. 1973, 66, 731. Niles, N. R., Bitensky, L., Chayen, J., Cunningham, G. J., Braimbridge, M. V. Lancet, 1964, i, 963. Braimbridge, M. V., Darracott, S., Clement, A. J., Bitensky, L., Chayen, J. J. thorac. cardiovasc. Surg. 1973, 66, 241. Darracott, S., Braimbridge, M. V., Bitensky, L., Chayen, J. ibid. p. 247.
(ng/ml) of 5-H.I.A.A. to the concentration of probenecid (fLg/ml) was 7.46+1.64 (n=6). This compares with 10-8±2.3 (n=5) (P>0.05) in patients with normal hepatic function. These results suggest that elevated baseline levels of 5-H.I.A.A. may not indicate an increased turnover ofc.N.s. 5-H.T. All our patients were out of coma at the time of the second lumbar puncture. We have since obtained data from a patient with marked portosystemic shunting of blood through collateral vessels who was in stage 5+ to 6+ hepatic coma before receiving probenecid and 6+ at the termination; the ratio of increase in 5-H.I.A.A. to concentration of probenecid was 8.3. This would indicate that C.N.S. turnover is unchanged in hepatic coma. These results suggest that altered tryptophan metabolism has little if any role in the aetiology of hepatic coma in cirrhotic
patients.
SIR,-I read with pleasure, and agreed with, much of Professor Alberti’s letter (Oct. 25, p. 820). As he says, it would indeed be simple to calculate osmolality if, as is often incorrectly implied, SI terminology stated that the units mosmol and mmol are interchangeable. Alas, it would also be wrong. Plasma and other biological fluids are complex non-ideal "solutions". If we want to know their osmolality it is still necessary to measure it. But that is another story. Department of Clinical Biochemistry, Royal Victoria Infirmary, Newcastle upon Tyne NE1 7RU.
SIR,-In the beginning we were conned by the jingoistic jargon of the innovators who
Laboratory of Neurochemistry,
Department of Psychiatry,
SAMARTHJI LAL
McGill University, 1033 Pine Avenue West,
SIMON N. YOUNG THEODORE L. SOURKES
Montreal, Quebec, Canada.
HBsAG SUBTYPES IN FULMINANT
HEPATITIS
SiR,-Hepatitis-B surface antigen (HBsAg) subtypes have been determined in 25 patients with fulminant type-B hepatitis from various parts of the United States. The patients had been enrolled in a cooperative prospective study of the effect of hepatitis-B immune globulin conducted by the acute-hepaticfailure study group of the American Association for the Study of Liver Disease.’ Serum specimens were provided with the consent of the participating physicians and Dr James W. Mosley, the project coordinator. Most specimens were subtyped by a double-antibody radioimmunoassay (R.LA.) method2capable of identifying the d, y,3 and g2 determinants of HBsAg. Two specimens whose serotypes could not be conclusively defined by this method were typed by a more sensitive technique based on the specimen’s absorption pattern for monospecific, anti-HBs d, y, and g antisera, using a commercial solid-phase anti-HBs R.I.A. (’Ausab’, Abbott Laboratories, Chicago) for detection of the unabsorbed antisera.4 The overall results were as follows:
adg(+) 10, adg(-) 1, ayg(+) 0, ayg(-) 14. Sera from 105 patients with uncomplicated acute hepatitis B from the Dallas area were subtyped previously ;2 42 were adg(+), 0 adg(-), 3 ayg(+), and 60 ayg(-). Although rigid comparision of the fulminant-hepatitis and uncomplicated-hepatitis-groups is unjustified because of the different origins of the populations, the data suggest no special propensity of a given viral subtype to produce the fulminant form of hepatitis. Department of Internal Medicine, Dallas Veterans Administration Hospital and University of Texas Southwestern Medical School, Dallas, Texas, U.S.A.
JAMES SHOREY SI UNITS
SIR,-Dr Clark and Dr Sheldon (Oct. 11, p. 700) state that the D.H.S.S. issued a Diktat "without consultation, discussion, approval, or consent". The document prepared by the working-party was sent for comment in draft form (in August, 1973) by the D.H.S.S. to 37 organisations. All replied, most made useful suggestions that were incorporated in the final document, none castigated the proposals or suggested waiting five more vears. Department of Chemical Pathology, Royal Free Hospital, Pond Street, London NW3 2QG.
D. N. BARON
so swiftly and brutally foisted those wretched SI units on us. We have now had time to appreciate the preposterously unwieldy scales of normal values, and the dangerously blurred areas beyond the "normal" limits. In the name of commonsense, let us have done with this arrant nonsense and return, while we still can, to the "old" system that was long tried and trusted, and which our English-speaking colleagues in the U.S.A. show no signs of abandoning. Were we to have a referendum within the profession as to whether or not we ought to stay with SI units, an overwhelming majority would vote to "come out" and to return to sanity. Meanwhile, I suppose the regular arithmetical gymnastics involved in translating back to the sensible values are good for the mind.
Burghmuir Hospital, Perth, Scotland.
SIR,-Myocardial preservation during open-heart surgery remains a major problem. Recently the method of pericardial cooling introduced by Shumway’s group1 has been gaining wide acceptance, because of both its simplicity and its good results. One of the most sensitive methods of detecting myocardial injury has been the ’study of histochemical changes of the myocardial tissue, and several groups of workers have correlated the clinical outcome after open-heart surgery with the histochemical assessment of myocardial dysfunction during surgery.2-4 This method, however, has not been used to examine the effects of local cooling on the myocardium. In collaboration with the department of biochemistry of the cardiothoracic unit at St. Thomas’s Hospital, London, I have used this method in 19 cases of mitral and aortic valve replacement. Samples of the left ventricular wall were obtained with a pneumatic-drill biopsy at the beginning and at the end of the bypass period. The samples were immediately cooled and examined for acid haematein, succinodehydrogenase, A. T.P .ase, monoamine oxidase, cytochrome oxidase, and birefringence in the relaxed and contracted state. Changes were classified according to the following scale: 0=good, 1=fairly good, 1-2=moderate, 2=poor, and 3 =bad. The total score of each biopsy at the beginning of the operation was compared with that of the biopsy at the end of the operation. An increase in the score indicated myocardial deterioration. Only in 3 out of 19 cases was there such a deterioration, and in all these the operation had had to be extended to over 70 minutes. This finding 1. 2.
Hepatic Failure Study Group. Gastroenterology, 1974, 66, 752 (abstract). Shorey, J. J. infect. Dis. (in the press). Le Bouvier, G. L. ibid. 1971, 123, 671. Shorey, J. Unpublished.
R. G. SIMPSON
MYOCARDIAL CELL INJURY DURING OPEN-HEART SURGERY
1. Acute 2. 3. 4.
C. T. G. FLEAR
3. 4.
Griepp, R. B., Stinson, E. B., Shumway, N. E. J. thorac. cardiovasc. Surg. 1973, 66, 731. Niles, N. R., Bitensky, L., Chayen, J., Cunningham, G. J., Braimbridge, M. V. Lancet, 1964, i, 963. Braimbridge, M. V., Darracott, S., Clement, A. J., Bitensky, L., Chayen, J. J. thorac. cardiovasc. Surg. 1973, 66, 241. Darracott, S., Braimbridge, M. V., Bitensky, L., Chayen, J. ibid. p. 247.
