摘要:

SUMMARY1. Plasma levels of propranolol were measured fluorometrically in patients with angina pectoris and in patients admitted to the Coronary Care Unit with acute myocardial infarction.2. In thirty patients with stable angina pectoris, plasma propranolol levels varied almost linearly with doses between 10 and 120 mg during 6‐hourly chronic oral administration. Plasma levels greater than 100 ng/ml produced 70–80% reduction in the tachycardia induced by strenous exercise on a treadmill.3. In nineteen patients with acute myocardial infarction given oral propranolol, 20 mg 6‐hourly, peak as well as trough plasma levels of the drug increased progressively but remained below 100 ng/ml in all except two patients during the first 24 h after their admission to the Coronary Care Unit.4. The data suggest that the use of low and fixed doses of propranolol may not produce adequate plasma levels or significant β‐adrenoceptor blockade in the early stages of acute myocardial infarctio

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00606.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. Two aspects of cholesterol absorption; (a) the importance of solubilization and (b) the effects of different bile salts on the mucosal metabolism and lymphatic output of cholesterol, have been investigated using two differentin vivotechniques.2. Bile diverted lymph fistula rats were infused intraduodenally at a steady rate with a constant lipid mixture containing labelled cholesterol, labelled oleic acid and mono‐olein. The lipids were completely solubilized in either bile salts or a non‐toxic non‐ionic detergent, Pluronic F68. Labelled fatty acid was efficiently absorbed from either micellar infusate but virtually no labelled cholesterol appeared in the lymph in the absence of bile salts.3. Short‐term perfusions of the intestine of anaesthetized rats with the same micellar perfusates as above showed approximately 20% of the labelled cholesterol in the mucosa after 30 min perfusion with the bile salt micellar solutions. When the non‐ionic micelles were used virtually no isotopic cholesterol left the lumen.4. Mucosal uptake of labelled cholesterol was linearly dependent on the concentration of solubilized cholesterol in the perfusate and was not dependent on the bile salt concentration.5. After 30 min the total amount of perfused isotopic cholesterol was recovered from either the lumen or the mucosa, but some fatty acid appeared to have been transported away from the mucosa by this time.6. The initial rate of mucosal uptake of labelled cholesterol was similar from micellar perfusates using either taurocholate, taurodeoxycholate or taurofusidate. In contrast, after 8 h of infusion, lymphatic output of labelled cholesterol was markedly greater with taurocholate.7. The increased lymph output with taurocholate was associated with an increase in the esterified fraction of both labelled and unlabelled cholesterol. Fatty acid was absorbed and esterified equally from all three types of perfusate.8. These results suggested that for the first step in cholesterol absorption,viz.uptake from the lumen, solubilization by a planar detergent was essential. After up take, the more rapid transfer of cholesterol to lymph in the presence of trihydroxy bile acids appeared to be related to a more efficient esterification of cholesterol, but not to a more efficient resynthesis of triglyceride, the other major component of lymph chy

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00607.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. The influence of the anorectic drugs fenfluramine, mazindol, mefenorex, phentermine and R 800, an experimental compound, on pulmonary vascular resistance has been studied in the isolated, perfused rat lung.2. R 800 caused a strong vasoconstriction, which was not antagonized by methysergide or phentolamine; the other drugs listed did not alter vascular resistance.3. Mazindol and phentermine significantly prolonged the vasoconstrictive effect of serotonin due to inhibition of its metabolic breakdown.4. Although fenfluramine inhibited serotonin metabolism it also prevented the vasoconstrictive effect of serotonin, due to its ability to act as a serotonin antagonist.5. Mefenorex did not affect pulmonary vascular resistance, either directly or indirectly via a serotoninergic mechanism.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00608.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. The peripheral blood concentrations of aldosterone, corticosterone and cortisol were measured during pregnancy in conscious, undisturbed sheep.2. Aldosterone levels did not change during pregnancy and the mean pregnant value, 1·2 s.d. 1·4 ng/100 ml (n= 12) was not significantly different from the non‐pregnant value, 2·1 s.d. 1·7 (n= 16).3. Cortisol levels likewise were unchanged by pregnancy–non‐pregnant values were 0·56 s.d. 0·50 μg/100 mi (n= 12) compared with 0·46 s.d. 0·40 μg/100 ml (n= 16) in pregnant sheep.4. Sheep of 110–140 days gestation had a 400 mmol greater total exchangeable sodium than non‐pregnant sheep. Plasma volume and plasma renin concentration tended to be elevated near to term.5. Very high aldosterone secretion rates and peripheral blood levels could be produced in pregnant sheep by stress, intravenous ACTH or angiotensin II infusions, and by sodium deficiency. It is suggested that the pregnant sheep may show increased sensitivity in contrast to non‐pregnant sheep to these stimuli and the enlarged size of their adrenals may be

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00609.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. The effects of 3‐hydrazine–6{N,N‐bis(2‐hydroxyethyl)amino}‐pyridazine dihydrochloride (L6150) were studied in intact anaesthetized dogs.2. In a dose of 1 mg/kg/(i.v.) the drug increased respiration rate, cardiac output, and left and right ventricular work.3. It decreased femoral pressure and systemic and total pulmonary resistance.4. It increased coronary flow and coronary sinus O2content.5. The drug also increased whole body glucose, lactate, pyruvate and NE

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00610.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. Tritiated (12α‐3H) digoxin (0·05 mg/kg body weight) was administered intravenously to conscious dogs with circulatory volume overload induced by previous creation of aorto‐caval fistulae. Dogs were killed after 5 min, 1, or 4 h, and the myocardium sampled. Digoxin was extracted and counted and results compared to those in normal dogs.2. At each time, myocardial digoxin concentration of all cardiac chambers in test dogs was greater than normal. Plasma digoxin concentration measured 5 min after administration was greater in dogs with fistulae but the subsequent levels were not different.3. Anaesthetized and open‐chest dogs with fistulae studied 5 min after digoxin administration had greater myocardial concentrations than similarly studied normal dogs. Although myocardial concentrations of digoxin were higher in anaesthetized than in conscious dogs the group with fistulae had higher values than did the normal group, as was the case for unanaesthetized dogs.4. The basis for the effect of fistula is probably multifactorial. Diminished peripheral blood flow and peripheral digoxin delivery and uptake, resulting initially in higher digoxin levels in plasma perfusing the myocardium, may play a role. Increased myocardial mechanical and metabolic activity almost certainly are important. Cardiac hypertrophy, cardiac failureper seand plasma electrolyte changes are probably not.5. The results are consistent with previously demonstrated reduced digitalis tolerance in the dog with circulatory volume o

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00611.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. The effects of histamine on cardiac force, heart rate and coronary perfusion pressure were studied in the isolated rat heart, using the Langendorff perfused heart preparation.2. Single injections of histamine induced dose‐dependent decreases in contractile amplitude, heart rate and coronary perfusion pressure.3. Perfusions of metiamide (above 1 × 10‐4M) had a depressant effect on contractile force and heart rate, whereas diphenhydramine (4 × 10‐6M) reduced only the heart rate. Both agents caused a fall in coronary perfusion pressure.4. The negative inotropic and chronotropic effects of histamine on the isolated rat heart were not significantly influenced by either metiamide or diphenhydramine, or a combination of these drugs. However, the fall in coronary perfusion pressure induced by injections of histamine was significantly antagonized by metiamide or diphenhydramine.5. These results suggest that the effects of histamine on the isolated rat heart may not be due entirely to stimulation of H1‐ or H2‐receptors on the cardiac muscle cells. Evidence is presented for the existence of histamine H1‐ and H2‐receptors in the c

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00612.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. The influence of histamine and histamine receptor blockade on the mitotic rate in epithelial cell proliferation in epithelial cells lining the crypts of Lieberkühn in rat jejunum was studied.2. Histamine injection resulted in an increase in the mitotic rate. This increase in mitotic rate was blocked by metiamide but not by mepyramine.3. Prevention of histamine synthesis by α‐methylhistidine administration did not alter the mitotic rate.4. The mechanism by which histamine may influence crypt cell proliferation and and possible role of cyclic GMP in this mediation are discus

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00613.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00614.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SUMMARY1. Choline was released into the fluid bathing the serosal surface of segments of guinea‐pig small intestine. The mean rate of release (nmol choline per cm of intestine per h) in the first hour was 10·2 and in the second hour 8·0.2. Propranolol 1 MM in the mucosal fluid caused a significant (P<0·01) increase in the rate at which choline was released into the serosal fluid. The mean rates were 15·4 and 19·2 for the first and second hour, respectively.3. It is suggested that the effect of propranolol observed in the present study is likely to be due to a non‐specific direct action on biological m

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1976.tb00615.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY