Serotonin stimulates protein phosphorylation in the cestode Hymenolepis diminuta

1. Serotonin stimulated the incorporation of 32P from [gamma-32P] ATP into crude membrane preparations (P2) of Hymenolepis diminuta in a dose-dependent manner (EC50 of approximately 0.79 microM). 2. This response was seen with several serotonin agonists, and was inhibited by several serotonin antagonists, which were identical to the previously described activation and inhibition of serotonin-sensitive adenylate cyclase. 3. Cyclic AMP produced a dose-dependent stimulation of 32P incorporation into the P2 fraction, with an EC50 of approximately 2.51 microM. 4. The targets for the serotonin stimulated incorporation of 32P were found to be in trypsin-labile proteins with Mr's of 134,000, 110,000, 82,000, 80,000 and 31,000.

Importância do exame físico-químico no diagnóstico de carcaças amareladas de suínos na rotina de inspeção

A coloração amarelada é un achado que pode levar à condenação de carcaças. Em uma amostragem de cento e oitenta e cinco carcaças de suínos que à inspeção apresentaram-se amareladas, sem outras lesões visíveis, foram realizados, como provas confirmativas, o - tratamento pelo frio e a reação de Remington-Fourrié. Os resultados mostram que em 158 delas persistiu a coloração amarelada, quando tratadas pelo frio, enquanto que pela técnica de Remington-Fourrié "foram detectadas cento e dezoito carcaças ictéricas. Isto mostra a eficiência desta prova na identificação de icterícia em carcaças amareladas, o que sugere sua utilização na rotina de inspeção.

Use of a double balloon technique for percutaneous balloon pulmonary valvotomy in adults

Percutaneous double balloon pulmonary valvotomy was performed on seven consecutive adult patients (mean age 26 years) with congenital pulmonary valve stenosis. The peak systolic transvalvar pressure gradient was significantly reduced from a mean (SD) of 104(30) to 24.3(6) mm Hg. This haemodynamic improvement was maintained at six week follow up. In six patients pulmonary infundibular spasm developed immediately after valvotomy; however, these patients showed considerable haemodynamic improvement at the six week follow up. During balloon inflation the heart rate did not fall below 60 beats/minute and the systemic aortic pressure was maintained above 90 mm Hg. Early results indicate that percutaneous double balloon valvotomy in adults is an effective treatment for isolated pulmonary valve stenosis. Theoretically the two balloons provide a venting area during inflation. This has the advantage of preventing bradycardia or systemic hypotension during prolonged balloon inflation.

Characterization of a serotonin transporter and an adenylate cyclase-linked serotonin receptor in the cestode Hymenolepis diminuta

[3H]5-HT exhibited specific binding in membrane preparations of Hymenolepis diminuta. The specific binding was saturable, reversible and temperature dependent. A non-linear Scatchard plot was obtained in a concentration range of 11 nM - 1000 nM [3H]5-HT, which could be resolved into sites having apparent dissociation constants (KD) of 0.10 microM and 6.25 microM for the high-affinity and low-affinity components, respectively. The latter could be selectively eliminated by binding [3H]5-HT to H. diminuta membranes in the presence of 10(-3) M nitroimipramine. Drug displacement studies, using 0.20 microM and 2.0 microM [3H]5-HT, revealed that while low-affinity [3H]5-HT binding was displaced by unlabelled 5-HT and inhibitors of 5-HT uptake, high affinity [3H]5-HT binding was affected only by tryptamine derivatives and, to a lesser extent, methysergide. In addition, high-affinity binding was stimulated by MgCl2 while low-affinity binding showed sodium-dependency. The data implicate the low-affinity site as a putative 5-HT transporter and the high-affinity site as a putative 5-HT 1 receptor. Exposure of H. diminuta membranes to 5-HT resulted in a 3-4 fold stimulation of cAMP levels. The EC 50 for the 5-HT-induced activation of adenylate cyclase (0.76 microM) was of the same order of magnitude as the apparent KD for high-affinity binding. Furthermore, the order of drug potency for the elevation of cAMP levels by 5-HT agonists and reversal by 5-HT antagonists was identical to the order of drug potency for the inhibition of high-affinity binding, suggesting linkage of the putative 5-HT 1 receptor to adenylate cyclase in H. diminuta.

Percutaneous balloon valvotomy in tricuspid stenosis

This report describes the first successful treatment of tricuspid stenosis by percutaneous double balloon valvotomy. There was a dramatic reduction of the tricuspid valve gradient, with an increase in calculated valve area, together with an increase in resting cardiac output and symptomatic relief. The feasibility of the non-surgical treatment of severe tricuspid stenosis was demonstrated unequivocally.

Right ventricular abnormalities in ventricular tachycardia of right ventricular origin: relation to electrophysiological abnormalities

Patients with right ventricular tachycardia may have adverse electrophysiological abnormalities linked to disturbed right ventricular structure. Seventeen patients who presented with right ventricular tachycardia without coronary artery disease or gross abnormalities of left ventricular function were studied. Patients had the ventricular tachycardia characterised at electrophysiological study and most underwent radionuclide and contrast angiography. At echocardiography specific attention was paid to the right ventricular chamber size. Two groups were identified at echocardiographic study. In group 1, nine patients had normal left ventricular dimensions and relatively normal features at electrophysiological study. Mean right ventricular ejection fraction was 0.45 by krypton-81 measurement. Group 2 comprised eight patients who had dilatation of right ventricular inflow tract, outflow tract, and right ventricular body. This group had more severe features at presentation and at electrophysiological study. In this group all available echocardiographic measurements of right ventricular chamber size were greater than those of group 1 and outside the normal range. Four of the eight patients in group 2 showed regional right ventricular dyskinesia at echocardiography. Mean right ventricular ejection fraction (0.23) in group 2 was significantly lower than in group 1. One patient in group 2 subsequently died. In patients with right ventricular tachycardia, those with less favourable prognostic features at electrophysiological study may have distinct abnormalities of right ventricular structure that can be identified at echocardiographic study. Echocardiography may be of value in the recognition of potentially malignant clinical and electrophysiological features in this group.

Demonstration of specific high-affinity binding sites for [3H]5-hydroxytryptamine in the cestode Hymenolepis diminuta

[3H]5-HT (0.16-8.32 nM) exhibited saturable and specific binding in membrane preparations of Hymenolepis diminuta. The saturation data produced a non-linear Scatchard plot which could be resolved into sites having apparent dissociation constants (Kd) of 0.17 and 8.30 nM for the high-affinity and low-affinity components, respectively. Drug displacement studies, using radioligand concentrations of 0.6 and 6 nM, revealed that the two [3H]5-HT binding components are pharmacologically distinct and do not conform to any known class of 5-HT recognition site. The physiological significance of these putative 5-HT receptors and their potential usefulness for the selection of new antiparasitic agents are discussed.

Pericarditis in infective endocarditis

Three patients with infective endocarditis who presented with severe precordial pain and pericardial rubs are described in whom sterile pericardial and pleural effusions were found. The pericardial pain disappeared and the effusions regressed with successful antibiotic treatment. A similar mechanism to the postmyocardial infarction syndrome is suggested.

Management of aortic left ventricular tunnel

A 22 year old man had a diagnosis of left ventricular aortic tunnel established during infancy. Surgical repair was deferred at that time because his severe aortic root deformity would also have required aortic valve replacement. His current lack of symptoms together with a normal exercise capacity could be used as an argument against routine early surgical repair of the tunnel, particularly when the possible need for additional aortic valve replacement is considered.

Role of transient ischaemia and perioperative myocardial infarction in the genesis of new septal wall motion abnormalities after coronary bypass surgery

To evaluate the role of ischaemia in the genesis of new septal wall motion abnormalities after coronary artery bypass surgery 45 patients were studied by cross sectional echocardiography before and 8-10 days after operation. Regional left ventricular wall motion was classified as normal, hypokinetic, akinetic, or dyskinetic. Septal wall motion abnormalities were correlated with electrocardiographic Q wave changes and serial serum MB creatine kinase measured before and 4, 7, 21, 48, and 72 hours after operation. Of the 14 patients who developed new septal wall motion abnormalities after operation two developed septal akinesis (both had perioperative infarction) and one new dyskinesis in the previously akinetic septal segment. Of the 11 patients with new septal hypokinesis, eight had normal serial creatine kinase MB values, two had raised values peaking four and seven hours after operation, with a return to normal values at 21 hours indicating transient ischaemia, and one had enzymatic criteria for perioperative infarction. Most new echocardiographic septal wall motion abnormalities after coronary artery bypass grafting are not caused by transient ischaemia, perioperative infarction, or generalised cell necrosis.

Duration of symptoms and the effects of a more aggressive surgical policy: two factors affecting prognosis of infective endocarditis

One hundred and six patients were analysed in order to assess the effect of a more aggressive surgical policy in relation to the delays in diagnosis of infective endocarditis. The average duration of symptoms before diagnosis was 9.7 weeks, even though the patients had sought medical advice at a relatively early stage of their illness (2.2 weeks). Three of the 29 (10.3%) patients who were treated surgically died and all three were operated upon five weeks or later after diagnosis. Seventy-seven patients did not have surgery and 15 died (19.5%). The outcome of surgical treatment for prosthetic valve endocarditis was no worse than for native valve endocarditis. The mortality of prosthetic valve endocarditis including early infections was 32% with medical but only 10% with surgical management compared with 14.5% and 10.5% in native valve endocarditis. Endocarditis cannot always be prevented but earlier diagnosis would reduce mortality and prevent complications. When medical treatment is failing then surgery should be considered early and urgently particularly in staphylococcal infection or when large mobile vegetations are recognized; surgery is mandatory in fungal endocarditis. Earlier diagnosis would greatly reduce the current high incidence of surgery, but that depends on a much heightened index of suspicion amongst both general practitioners and hospital physicians.

Failure of transdermal nitroglycerin to improve chronic stable angina: a randomized, placebo-controlled, double-blind, double crossover trial

We assessed the effect of transdermal nitroglycerin (NTG-TTS), releasing 5 mg/24 hr, in 11 patients with chronic stable angina during a randomized, placebo-controlled, double-blind, double crossover trial of four 1-week periods. All patients had a positive exercise test and coronary artery disease prior to entry into the study. Efficacy was assessed weekly by anginal diaries, ambulatory ST segment recordings, and computerized exercise testing 2 to 4 hours after renewal of NTG-TTS. One patient withdrew in the first week (placebo) and was excluded from all analysis. The weekly frequency of anginal attacks was 9 +/- 11 (mean +/- SD) and 9 +/- 10 during the 2 placebo weeks and 11 +/- 14 and 9 +/- 11 during NTG-TTS; the time to 1 mm ST segment depression (seconds) was 268 +/- 178 and 303 +/- 217 with placebo and 228 +/- 221 and 285 +/- 178 with NTG-TTS; exercise duration (seconds) was 375 +/- 230 and 467 +/- 254 during placebo and was 394 +/- 233 and 412 +/- 236 during NTG-TTS. The weekly number of episodes of ST depression was 11 +/- 9 and 8 +/- 5 during placebo and 8 +/- 5 and 9 +/- 7 during NTG-TTS. Our study failed to show any consistent differences in patients treated with placebo or NTG-TTS.

Different mechanisms for the relief of angina after coronary bypass surgery. Physiological versus anatomical assessment

To determine the physiological effect of coronary artery bypass surgery and the mechanisms for pain relief, 15 patients with exertional angina were studied before and after operation. Before the operation conventional tests included exercise tests (all positive) and coronary angiography (all patients had greater than or equal to 70% stenosis of major vessels). In addition, ambulatory electrocardiographic monitoring during 48 hours detected 92 episodes (greater than or equal to 1 mm) of ST depression. Regional myocardial perfusion was assessed with positron tomography using rubidium-82 (t1/2 78 s) and this showed reversible inhomogeneity with absolute regional reduction of cation uptake after exercise in all 15 patients. After coronary surgery 10 of the 15 patients had (a) no angina, (b) patent grafts (three or more), (c) no evidence of ischaemia during ambulatory monitoring out of hospital, and (d) homogeneous perfusion with reversal of the disturbances in regional myocardial perfusion after exercise. After operation one of the 15 patients had no angina and showed silent infarction in the segment that was previously ischaemic but supplied by a patent graft. All but one of the remaining patients had no angina, patent grafts, but disturbances of regional myocardial perfusion with silent ischaemia on exercise. Two of these patients continued to have asymptomatic and ischaemic episodes of ST depression during ambulatory monitoring out of hospital. This physiological study of regional myocardial perfusion in patients in hospital and in those with ischaemia out of hospital showed that three different mechanisms may account for the relief of pain--improved perfusion, infarction, and silent ischaemia. Silent ischaemia in particular raises puzzling pathophysiological and therapeutic questions that may affect prognosis and the interpretation of clinical trials.

Interpretation of changes in the activity of creatine kinase MB isoenzyme in serum after coronary artery bypass grafting

Measurement of CK-MB in the sera of patients undergoing coronary artery bypass grafting shows a significant increase above pre-operative levels in all cases. However, the timing of the peak post-operative activity and its level allow criteria to be proposed which differentiate between two classes of patients: those with myocardial infarction or lesser myocardial damage, in whom peak activities are seen in specimens taken 21 hours after operation; and those in whom peak activities are found in specimens taken 4-7 hours after operation, presumably reflecting reversible myocardial changes. Activity peaks of more than 50 U/l occurring at 21 hours are considered to support a diagnosis of myocardial infarction.

Left ventricular function in patients with ankylosing spondylitis and Reiter's disease

We have studied left ventricular function by non-invasive methods in 28 patients with ankylosing spondylitis and 14 with Reiter's disease and compared them with 42 normal subjects. A dilated and poorly contracting left ventricle with abnormal systolic time intervals were found in five (18%) of those with ankylosing spondylitis and two (14%) with Reiter's disease. Our results suggest that the high cardiovascular morbidity and mortality in these diseases may be due to abnormality of the myocardium in the absence of valve disease.

Cigarette smoking and the treatment of angina with propranolol, atenolol, and nifedipine

To determine whether cigarette smoking affects the results of drug treatment for angina, we studied 10 cigarette smokers with angina who were given placebo, nifedipine (60 mg per day), propranolol (240 mg per day), and atenolol (100 mg per day), each for one week. The four-week double-blind study was repeated with the same randomly determined order of drug sequences, after all 10 subjects had stopped smoking. Before and after the subjects stopped smoking, all three drugs significantly reduced the frequency of angina, as measured with angina diaries, and improved the results of maximal exercise testing and 48-hour ambulatory monitoring of ST segments (P less than 0.01). However, during the nonsmoking phase of the study, there was an overall decline in the frequency of angina and an improvement in performance on exercise testing (P less than 0.05) as compared with the smoking period, although the results of 48-hour ambulatory monitoring remained unchanged. The improvement after patients stopped smoking was greater during treatment with nifedipine than during administration of the other two drugs or placebo. Blood levels of propranolol were increased when patients stopped smoking; levels of nifedipine and atenolol were unchanged. Our data show that smoking had direct and adverse effects on the heart and interfered with the efficacy of all three anti-anginal drugs, but with nifedipine the most.

Constrictive pericarditis as a complication of coronary artery bypass surgery

Although it is now recognised as a rare complication of cardiac surgery, constrictive pericarditis was diagnosed in three patients after coronary artery bypass surgery. The time interval between cardiac surgery and the development of constrictive features varied from two to six weeks. All three patients presented with severe congestive heart failure. Haemodynamic findings were characteristic of constrictive pericarditis. Pericardial thickening detected by computed tomography in one patient was useful in establishing a definite diagnosis. One of the patients had a serous constrictive effusive pericarditis, and surgical pericardial drainage was needed. The other patient underwent pericardiectomy with preservation of the grafts. The diagnosis of constrictive pericarditis should be considered in patients presenting with unexplained right sided heart failure after cardiac surgery.

The interaction of cigarette smoking and beta-adrenoceptor blockade

The importance of the interaction between smoking and propranolol (metabolised in the liver) and atenolol (excreted almost entirely in the urine) was investigated in a double-blind placebo-controlled trial. Resting and exercise heart rates were significantly greater during smoking than no-smoking phases. Atenolol and propranolol significantly improved ST segment response after exercise whether or not the patients were smoking. Plasma propranolol significantly increased when patients stopped smoking whereas there was no such change in atenolol levels.

The occurrence, synthesis and metabolism of 5-hydroxytryptamine and 5-hydroxytryptophan in the cestode Hymenolepis diminuta: a high performance liquid chromatographic study

The biosynthesis and metabolism of 5-hydroxytryptamine (serotonin; 5-HT) in the cestode Hymenolepis diminuta was investigated by High Performance Liquid Chromatography (HPLC). Incubation of intact H. diminuta in [3H]tryptophan resulted in substantial radioactivity recovered in 5-HT, 5-hydroxytryptophan (5-HTP), and 5-hydroxyindoleacetic acid (5-HIAA). Furthermore, the tissue levels of 5-HT and 5-HTP, as determined by HPLC with electrochemical detection, were significantly depressed when the animals were deprived of tryptophan. On the other hand, the tissue levels of 5-HTP were significantly increased following incubation with the 5-HTP decarboxylase inhibitor m-hydroxybenzylhydrazine. The synthesis and metabolism of 5-HT are discussed in the light of 5-HT as a physiological transmitter in H. diminuta.

Cross sectional echocardiographic assessment of the aortic root and coronary ostial stenosis in familial hypercholesterolaemia

Aortic root abnormalities (atherosclerotic thickening and obstruction) seen at necropsy may readily be detected by aortography in familial hypercholesterolaemia. We studied 35 patients with familial types IIa and IIb hyperlipoproteinaemia including three homozygotes and 32 heterozygotes. Two homozygotes showed abnormal bright echoes (atheroma) encircling the proximal aortic root, which interfered with full excursion of the aortic cusps. One homozygote showed the typical echocardiographic features of supravalvular aortic stenosis at the superior border of the sinus of Valsava with normal aortic cusps. Cardiac catheterisation showed valvular gradients of 15 and 80 mm Hg in two homozygotes and a supravalvular gradient of 40 mm Hg in the third. Left coronary artery ostial stenosis was identified by echocardiography in all three homozygotes. Echocardiographic measurements of the aortic root in the 32 heterozygotes were similar to the control group, but 10 patients showed abnormal bright echoes within the aortic cusps and four had supravalvular changes similar to, but less severe than, the homozygotes. In one severely heterozygote supravalvular atheroma prevented full aortic cusp excursion, and this finding was confirmed during coronary artery bypass surgery.

Myocardial ischaemia during daily life in patients with stable angina: its relation to symptoms and heart rate changes

In thirty patients with stable angina and positive exercise tests, ambulatory ST segment monitoring was used to record episodes of transient myocardial ischaemia during daily life. All patients had four consecutive days of monitoring and in 20 patients long-term variability was assessed by repeated 48 hour monitoring and exercise testing over 18 months. There were 1934 episodes of rectilinear or downsloping ST-depression (911, 1 mm; 638, 2 mm; 385, greater than 3 mm) in 446 days of recording, of which only 470 (24%) were accompanied by angina. Positron tomography showed evidence of regional myocardial ischaemia during both symptomatic and asymptomatic ST depression. On average, heart rate at the onset of both symptomatic and asymptomatic ST episodes was significantly lower than the rate at the onset of ST depression during exercise testing (98 +/- 20.5 vs 124 +/- 17 beats/minute). Heart rate rose by more than 10 beats in the minute preceding ST depression in only 23% of episodes. Over 18 months, 8 (40%) patients exhibited marked variability in the number of daily ST episodes. Variability of ST depression was consistently underestimated by symptoms and not reflected by exercise testing. Thus, patients with stable angina showed frequent, variable, and often asymptomatic electrocardiographic evidence of ischaemia. Heart rate increase was not common before myocardial ischaemia, suggesting that, in such patients, transient impairment in coronary supply may be at least as important as excessive increase in demand in the genesis of ischaemia during daily life.

Collagen content of atherosclerotic arteries is higher in smokers than in non-smokers

The biochemical composition of coronary endarterectomy and aortic samples obtained during 52 coronary artery bypass graft operations was analysed. The content of cholesterol or collagen relative to protein in the aorta or endarterectomy specimens did not correlate with serum total cholesterol, triglyceride, or high-density-lipoprotein cholesterol, nor were there any significant differences between samples from normotensive and hypertensive patients. However, smokers had a significantly higher content of collagen in coronary endarterectomy specimens and the aorta and a higher content of cholesterol in the aorta than non-smokers.