摘要:

AbstractPermeability coefficients for water‐soluble substances of different molecular weights and hydraulic conductivities were measured using the isolated mesentery of the dog. The permeability coefficients of all investigated substances show the same relation to each other as the diffusion coefficients in free solution. From these data we conclude that these substances pass the mesentery by free diffusion in aqueous channels. The fraction of the endothelial membrane area which is free for diffusion was calculated to be 4%. No steric hindrance was observed even for the largest molecule (dextran mol. wt. 500000). From the hydraulic conductivity and the diffusion permeability for water a mean equivalent pore radius of 0.575 μ was calculated for the endothelial cells. We conclude that the limiting membrane for peritoneal dialysis is the capillary endotheli

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00610.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe rate of turnover and oxidation of plasma free fatty acids (FITA) was measured in 7 normal anaesthetized dogs infused at a constant rate with l‐14C‐palmitate for 5 h. After a control period, sustained hyperketonaemia was induced by infusing sodium aceto‐acetate (AA). This produced a fall in plasma FFA (33%) and in blood sugar (24%), without changes in immuno‐reactive insulin (IRI) concentrations. During the control period, the turnover rate of carbon of FFA averaged 131 μat./kg/min, 32% of which were oxidized, thus supplying 17.7% of the total CO2production. At the end of the AA infusion, the mean turnover rate of FFA was reduced to 75μat.C/kg/min; since only 13.9 % of these were oxidized, the contribution of FFA to total CO2production was reduced to 4.3%. In the light of previous work showing that ketone infusions also reduce the rate of turnover and oxidation of glucose in dogs, we conclude that, under appropriate experimental conditions, ketones may strongly reduce the role of FFA and glucose as sources

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00611.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThis study contrasts the absorption from mixed micellar solutions and from emulsions of the polar lipid, oleic acid, and the non‐polar lipid, α‐tocopherol. Rats with cannulated mesenteric lymphatics and bile ducts were infused intra‐duodenally with14C‐oleic acid and3H‐α‐tocopherol, and absorption of radioactivity into lymph was measured during the subsequent 24 hours. The results showed that oleic acid was absorbed nearly as well from an emulsion as from a mixed micellar solution, in contrast to α‐tocopherol, which was absorbed poorly from the emulsion. Further studies in bile fistula rats killed at one and three hours after the intraduodena infusions showed that the poor absorption of α‐tocopherol from an emulsion was associated with a decreased uptake into the intestinal mucosa. These findings suggest that micelle formation is more important for the absorption of non‐polar lipids, such as α‐tocopherol, than for the absorption of polar li

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00612.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractA method is described for the quantitative study of the life cycle of microaneurysms in diabetic retinopathy. This method was applied to a series of 21 patients, 9 with mild and 12 with severe retinopathy, 6 of whom had pituitary ablation. — The study showed a variable survival of microaneurysms; overall disappearance rates were 3.3%/month in mild and 3.2 %/month in severe retinopathy. The disappearance rate was almost always higher in the early months of the study (11.6% and 9.3 % per month) than later (0.8 % and 1 %/month) indicating more than one population of microaneurysms. — There was no significant difference in the formation and disappearance of microaneurysms between patients with mild and severe retinopathy. — Some microaneurysms showed intermittent perfusion. — Following pituitary ablation the disappearance rate of microaneurysms increased, while the formation rate of new ones decreased signif

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00613.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe cat, when its peripheral metabolic demands are augmented, has a limited capacity to increase its heart rate, but often responds with a considerable rise in stroke volume: stroke volume can be increased by active changes of posture from lying to standing, by a short or prolonged bout of fighting, and by mild exercise on the treadmill. In all these conditions stroke volume attains values larger than those measured during recumbent rest. It appears therefore that an increase in stroke volume is a mechanism ordinarily called upon in the cat when natural behaviour requires an increase in cardiac output, while in man it is called upon in extraordinary conditions only. However, the fact that a stroke volume regulating mechanism is ordinarily operative in the cat shows that it has a physiological significance, and supports the idea that in man also exertion is accompanied by a masked stimulation of myocardial contractility. A description is also presented of the vasomotor changes produced by active changes in posture.

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00614.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractCapsular and decapsulated adrenal glands of rats kept on different diets were separately incubated with and without stimulators of aldosterone biosynthesis. The steroidogenic effect of serotonin, potassium ions and angiotensin II was limited to the capsular portion (zona glomerulosa), whereas ACTH and cyclic AMP acted on both the capsular and the decapsulated portion (zona fasciculata‐reticularis) of the adrenal cortex. In capsular adrenal glands of normal and sodium‐deficient rats all these agents stimulated aldosterone production severalfold and had a smaller effect on corticosterone output. Sodium deficiency led to a decreased response in corticosterone and deoxycorticosterone output. In capsular glands of potassium‐deficient rats the stimulators did not enhance aldosterone production but actsd mainly on deoxycorticosterone output. ACTH enhanced corticosteron e and deoxycorticosterone output to a similar extent in decapsulated glands of all groups of experimental animals. These results indicate a zone specificity of certain stimulators and confirm that they act at an early stage in the corticosteroid biosynthetic pathway preceding the formation of deoxycorticosterone. On the other hand, changes in sodium and potassium balance induce alterations in the activity of the enzymes involved in the conversion of deoxycorticosterone to aldosterone and thus influence the steroidogenic response of the zona glomerulosa to stimulating a

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00615.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractIn duodenal secretions from healthy adults and infants (aged 4–14 weeks) the level of immunoglobulins was measured by radial immunodiffusion. In the material from adult individuals, the antibody activity against common pathogenic bacterial strains was measured by means of the opsonin test. The antibody activity of duodenal secretions from infants vaccinated orally with an extract of 9 pathogenicE. coliserotypes was studied by the haemagglutination technique.—IgA is the predominant globulin of adult duodenal secretions, closely followed by IgM. In this material a clear‐cut opsonizing activity was shown to be present with several pathogenic strains of bacteria. The definite role of antibodies was demonstrated by absorption experiments with anti‐human globulin serum.—Purified secretory IgA and IgM were used as opsonizing agents. It was shown that complement enhances the phagocytic activity of IgM only, whereas lysozyme stimulates phagocytosis with both IgA and IgM.—Infants vaccinated with an extract of pathgogenicE. colishowed no evidence of antibody activity in their serum whereas a strong antibody activity was found in the duodenal secretions. Following immunisation the immunoglobulin content of secretions increased significantly. In early collected specimens, the antibody response was made mainly of IgM whereas in late specimens almost all the antibody activity was made of IgA, suggesting a typical prima

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00616.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe reactivity to the pressor action of tyramine, noradrenaline, and angiotensin was determined in 9 patients with hypertension, aldosteronism and low plasma renin concentration (4 patients with solitary adrenal adenomas, 3 patients with nodular adrenal hyperplasia, 2 patients with unknown adrenal status). In 7 patients tests were repeated following unilateral or subtotal adrenalectomy respectively. For comparison, 5 patients with phaeochromocytoma, 10 patients with benign essential hypertension, and 12 normotensive control subjects were studied. — In the hypertensive patients with aldosteronism and low plasma renin, responsiveness to tyramine was significantly reduced. In contrast, pressor response to noradrenaline was in the normal range, and sensitivity to angiotensin was increased. Following adrenal surgery, sensitivity to tyramine increased in all cases but one, sensitivity to noradrenaline did not change significantly, and responsiveness to angiotensin decreased in all cases but one. — It is discussed that the reduced pressor effect of tyramine in the hypertensive patients with aldosteronism is due to a disturbance of adrenergic function which may be of importance for the diminished production of renin in these forms of hypertens

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00617.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Abstract.1. Free fatty acid production by the fat cake of adipose tissue was found to be much greater in fasted‐refed than in fasted and fed rats, respectively. Preincubation with adrenalin and dibutyryl cyclic AMP stimulated lipase activities in fasted and fed rats, but not in fasted‐refed rats. Basal lipase activity in the fat cake of fasted‐refed rats was higher than adrenalin or dibutyryl cyclic AMP activated lipase activity of fasted or fed rats. Activation of lipase activity by refeeding lasted for several days.—2. Lipase activity in the aqueous phase of adipose tissue homogenate of all rats was in the same range.—3. Free fatty acid release during the assay of lipase in the fat cake proceeded for a period of up to 120 minutes although not in an entirely linear manner. The ratio of free fatty acids to glycerol release was 2.9. The pH optimum of the reaction was 7.4. NaCl, NaF, protamine and heparin markedly inhibited the lipase reaction. Heparin in the preincubation medium did not reduce the lipase activity in the fat cake.— 4. The very active triglyceride lipase activity of adipose tissue of fasted‐refed rats explains earlier findings showing that intact adipose tissue of fasted‐refed rats exhibits a very high glycerol release. It appears that tissue levels of triglyceride lipase increase during refeeding under the influence of insulin, i.e. at a time when the level of cyclic AMP in the tissue su

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1970.tb00618.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY