1191 CESOPHAGEAL PERISTALTIC PRESSURES
(A4EAN+SD)
AFTER WET
(10 II11 WATER)
AND DRY
SWALLOWS7
B=bethanechol. A=atropine.
mainly inhibitory for both secretion and motility. Does smoking inhibit dopamine release? Again circumstantial evidence is not on Szabo’s side. With the lower a:sophageal sphincter as the target organ smoking reduces sphincter pressure,s as does dopamine.6 Other factors may be more important, but for this particular structure dopamine antagonism be
does not appear to exist. Detailed study of oesophageal motility has not revealed any evidence of peripheral dopamine depletion in Parkinson’s disease(again assuming that depletion produces the opposite effect of abundance, which it may not). The responses to bethanechol and atropine were also similar to those in controls
(table). Clearly the situation is complex, and at least in parkinsonian patients there is no evidence of peripheral dopamine depletion. How then do we explain Strang’s findings? If Szabo is correct, then this raises the possibility that the disease promuch earlier in life at a subclinical level. It is possible that dopamine depletion is later compensated for by a change in neurotransmitter, or that the effect of dopamine depletion is negated by the worsening vagal function associated with increasing age. Both these possibilities exists Wherever the truth lies, we are likely to hear a lot more about the role of dopamine in duodenal ulcer disease in the coming years. cess starts
Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP
M. G. BRAMBLE
TIQUINAMIDE
SiR,—Tiquinamide (Wy 24081) is a potent inhibitor of gasgives good protection in animals against gas-
tric secretion and
tric and duodenal erosions induced by stress and chemical stimuli. It reduces basal as well as stimulated acid secretion but has no anticholinergic activity and is only a weak histamine Hz antagonist. Since no other pharmacological effect of tiquinamidehas been detected in isolated tissues, it seems unlikely that the gastric antisecretory effect of the compound results from a direct action on the peripheral autonomic nervous system.’ The report from Dr Szabo (Oct. 27, p. 880) on the protective effect of dopamine agonists against duodenal ulceration suggests a possible mechanism of action for tiquinamide. The figure shows the structural similarity between tiquinamide and the dopamine agonists bromocriptine and lergotrile and dopamine itself. Department of Clinical
Pharmacology, St. Bartholomew’s Hospital, London EC1A 7BE
(b) tiquinamide, (c) bro-
Chattopadhyay DK, Grearey MG, Irvin TT. Effect of cigarette smoking on the lower œsophageal sphincter. Gut 1977; 18: 833-35. 2. Mukhopadhyay AK, Weisbodt N. Effect of dopamine on œsophageal motor function. Am J Physiol 1977; 232: E 19-24. 3. Bramble MG, Cunliffe J, Dellipiani AW. Evidence for a change in neurotransmitter affecting œsophageal motility in Parkinson’s disease. J Neurol Neurosurg Psychiat 1978; 41: 709-12.
P. TURNER
TRIAL OF PNEUMOCOCCAL VACCINE FOR ASPLENIC PATIENTS
SIR,-The risk of pneumococcal infection to patients who have had their spleens removed is well recognised.2,3 Polyvalent pneumococcal vaccine has been recommended for asplenic patients, and is now available in the U.K. Although we have read the paper of Ammann et awl. we believe that the efficacy of the vaccine in asplenic patients is unproved, and that there are reasons to question its efficacy.5,6 We have designed a controlled trial of vaccine in patients after splenectomy. We propose to give penicillin prophylaxis to all patients, and randomly to allocate half to receive vaccine. Follow-up will last three years. However, a single centre will take several years to collect enough patients for a trial, whereas there is a pressing need to decide whether the vaccine is effective in asplenic patients. We invite others who care for children and adults after splenectomy to join us in a multicentre trial. The protocol may be obtained from R.T.M.-W. P. M. EMERSON M. P. E. SLACK H. M. CHAPEL John Radcliffe Hospital, R. T. MAYON-WHITE Headington, Oxford OX3 9DU
DE, Dixon GT, Waterfall JF, Alps BJ. The gastro-intestinal and autonomic effects of 3-methyl-5, 6, 7, 8-tetrahydroquinoline-8-thiocarboxamide hydrochloride (tiquinamide). Arzneimitt Forsch 1979; 29: 1564-69. Editorial Infective hazards of splenectomy. Lancet 1976; i: 1167-68. Editorial. After splenectomy. Br Med J 1978; ii: 1042-43. Ammann AJ, Addiego J, Wara DW, et al. Polyvalent pneumococcal-polysaccharide immunisation of patients with sickle-cell anæmia and patients with splenectomy. N Engl J Med 1977; 297: 897-900. Giebank GS, Quie PG, Schiffman G. Serum-opsonic activity and opsonic response to pneumococcal vaccine in splenectomised children. In: Parker MT, ed. Pathogenic streptococci. Reedbrooks, 1979: 195-6. Applebaum PC, Shaikh BS, Widome MD, et al. Fatal pneumococcal bacteremia in a vaccinated, splenectomised child. N Engl J Med 1979; 300: 203-04.
1. Beattie
Molecular structures of (a) dopamine, mocriptine, and (d) lergotrile.
A. JOHNSTON S. J. WARRINGTON
2. 3. 4.
1.
5.
6.
(A4EAN+SD)
AFTER WET
(10 II11 WATER)
AND DRY
SWALLOWS7
B=bethanechol. A=atropine.
mainly inhibitory for both secretion and motility. Does smoking inhibit dopamine release? Again circumstantial evidence is not on Szabo’s side. With the lower a:sophageal sphincter as the target organ smoking reduces sphincter pressure,s as does dopamine.6 Other factors may be more important, but for this particular structure dopamine antagonism be
does not appear to exist. Detailed study of oesophageal motility has not revealed any evidence of peripheral dopamine depletion in Parkinson’s disease(again assuming that depletion produces the opposite effect of abundance, which it may not). The responses to bethanechol and atropine were also similar to those in controls
(table). Clearly the situation is complex, and at least in parkinsonian patients there is no evidence of peripheral dopamine depletion. How then do we explain Strang’s findings? If Szabo is correct, then this raises the possibility that the disease promuch earlier in life at a subclinical level. It is possible that dopamine depletion is later compensated for by a change in neurotransmitter, or that the effect of dopamine depletion is negated by the worsening vagal function associated with increasing age. Both these possibilities exists Wherever the truth lies, we are likely to hear a lot more about the role of dopamine in duodenal ulcer disease in the coming years. cess starts
Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP
M. G. BRAMBLE
TIQUINAMIDE
SiR,—Tiquinamide (Wy 24081) is a potent inhibitor of gasgives good protection in animals against gas-
tric secretion and
tric and duodenal erosions induced by stress and chemical stimuli. It reduces basal as well as stimulated acid secretion but has no anticholinergic activity and is only a weak histamine Hz antagonist. Since no other pharmacological effect of tiquinamidehas been detected in isolated tissues, it seems unlikely that the gastric antisecretory effect of the compound results from a direct action on the peripheral autonomic nervous system.’ The report from Dr Szabo (Oct. 27, p. 880) on the protective effect of dopamine agonists against duodenal ulceration suggests a possible mechanism of action for tiquinamide. The figure shows the structural similarity between tiquinamide and the dopamine agonists bromocriptine and lergotrile and dopamine itself. Department of Clinical
Pharmacology, St. Bartholomew’s Hospital, London EC1A 7BE
(b) tiquinamide, (c) bro-
Chattopadhyay DK, Grearey MG, Irvin TT. Effect of cigarette smoking on the lower œsophageal sphincter. Gut 1977; 18: 833-35. 2. Mukhopadhyay AK, Weisbodt N. Effect of dopamine on œsophageal motor function. Am J Physiol 1977; 232: E 19-24. 3. Bramble MG, Cunliffe J, Dellipiani AW. Evidence for a change in neurotransmitter affecting œsophageal motility in Parkinson’s disease. J Neurol Neurosurg Psychiat 1978; 41: 709-12.
P. TURNER
TRIAL OF PNEUMOCOCCAL VACCINE FOR ASPLENIC PATIENTS
SIR,-The risk of pneumococcal infection to patients who have had their spleens removed is well recognised.2,3 Polyvalent pneumococcal vaccine has been recommended for asplenic patients, and is now available in the U.K. Although we have read the paper of Ammann et awl. we believe that the efficacy of the vaccine in asplenic patients is unproved, and that there are reasons to question its efficacy.5,6 We have designed a controlled trial of vaccine in patients after splenectomy. We propose to give penicillin prophylaxis to all patients, and randomly to allocate half to receive vaccine. Follow-up will last three years. However, a single centre will take several years to collect enough patients for a trial, whereas there is a pressing need to decide whether the vaccine is effective in asplenic patients. We invite others who care for children and adults after splenectomy to join us in a multicentre trial. The protocol may be obtained from R.T.M.-W. P. M. EMERSON M. P. E. SLACK H. M. CHAPEL John Radcliffe Hospital, R. T. MAYON-WHITE Headington, Oxford OX3 9DU
DE, Dixon GT, Waterfall JF, Alps BJ. The gastro-intestinal and autonomic effects of 3-methyl-5, 6, 7, 8-tetrahydroquinoline-8-thiocarboxamide hydrochloride (tiquinamide). Arzneimitt Forsch 1979; 29: 1564-69. Editorial Infective hazards of splenectomy. Lancet 1976; i: 1167-68. Editorial. After splenectomy. Br Med J 1978; ii: 1042-43. Ammann AJ, Addiego J, Wara DW, et al. Polyvalent pneumococcal-polysaccharide immunisation of patients with sickle-cell anæmia and patients with splenectomy. N Engl J Med 1977; 297: 897-900. Giebank GS, Quie PG, Schiffman G. Serum-opsonic activity and opsonic response to pneumococcal vaccine in splenectomised children. In: Parker MT, ed. Pathogenic streptococci. Reedbrooks, 1979: 195-6. Applebaum PC, Shaikh BS, Widome MD, et al. Fatal pneumococcal bacteremia in a vaccinated, splenectomised child. N Engl J Med 1979; 300: 203-04.
1. Beattie
Molecular structures of (a) dopamine, mocriptine, and (d) lergotrile.
A. JOHNSTON S. J. WARRINGTON
2. 3. 4.
1.
5.
6.
