摘要:

Abstract.Biliary secretion of bile salts and bile flow were studied in Sprague Dawley rats with liver atrophy resulting from an end‐to‐side portacaval shunt and in sham‐operated controls. Three weeks after the shunt operation the liver to body weight ratio was reduced by 41%. This hepatic atrophy was accompanied by a reduced bile flow, which was 4.9 ± 0.3 (SEM) and 5.9 ± 0.2 (SEM) μ/min per 100 g body wt. in shunted and sham‐operated animals, respectively. By contrast, bile salt pool size and bile salt secretion were not significantly changed by the portacaval shunt. Shunted animals maintained a normal bile salt pool size by increasing bile salt synthesis per unit of liver weight. Thus, cholate synthesis, calculated from cholate pool size and14C‐cholate turnover rate, was 3.3 ± 0.4 (SEM) and 1.8 ± 0.2 (SEM) μmol/24 h per g liver in shunted and sham‐operated rats, respectively. It is concluded that the atrophic liver in the rat with a portacaval shunt is able to maintain normal bile salt secretion rates and that the observed decrease of bile flow results from a diminution of bile salt independe

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02338.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract.Previous studies of intrarenal haemodynamics by wash‐out with inert gas suggested that haemorrhagic hypotension (HH) in the dog causes a redistribution of intrarenal blood flow with a patchy cortical hypoperfusion, mainly due to an increased concentration of circulating catecholamines. In the present experiments intrarenal haemodynamics were studied by the same methods in the rat during prolonged HH with a mean arterial BP of 51 mm Hg. Under these conditions inert gas wash‐out studies showed a decrease in compartment I (CP I) flow fraction (“cortical flow fraction”) from 81.5% to 43.2% of total renal blood flow (RBF). CP I blood flow dropped from 3.13 ml/min. to 0.63 ml/min. per g kidney weight. Total renal vascular resistance increased by a factor of 1.2 as compared with control conditions. These changes in intrarenal haemodynamics were considerably smaller than those observed in the dog under comparable conditions. In contrast to observations in the canine kidneynopatchy areas of cortical hypoperfusion occurred in the rat, and there was no evidence of stratification of cortical blood flow during HH. Instead, there was an even reduction in cortical blood flow from the subcapsular area to the cortico‐medullary border as indicated by inert gas wash‐out studies and85krypton autoradiographs. The meaning and pathogenesis of the observed differences between both species remains to be defined. It is suggested that in the rat the reaction of the renal vasculature to sympathoadrenal stimuli and/or to angiotensin might be different from that

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02339.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract.The specific radioactivities in serum and bile were compared in patients recovering from biliary surgery after intravenous injection of131I‐labelled albumin, orosomucoid, transferrin and immunoglobulins IgA and IgG. It was found that the major plasma proteins occurring in hepatic bile are entirely derived from the circulating plasma, except for part of the IgA which is of local origin.—A comparative analysis of the concentrations of the different proteins in the two media further indicates that transfer from plasma to bile proceeds along two parallel pathways. One of these consists of bulk transport without distinction being made between the proteins; the other one involves a selection of the proteins as a function of their molecular size, revealing the existence of a semi‐permeable barrier interposed between the plasma and the biliary compartments. To account for the observed sieve effect, the pores of this membrane ought to have a mean radius of about

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02340.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract.In the dog, as shown before in the human, the major plasma proteins in hepatic bile (albumin, orosomucoid, transferrin and immunoglobulin IgG), with the exception of immunoglobulin IgA, were found to be derived entirely from the plasma. Biliary IgA was shown to have two sources, the plasma and local biosynthesis. These conclusions were based on comparisons on specific radioactivities of different proteins in plasma and bile, after intravenous injection of canine plasma whose proteins had been labelled biosynthetically with tritium. — The transfer of plasma proteins from blood to bile was found to proceed along two parallel pathways, one involving bulk transfer of unmodified plasma, and one based on molecular sieving favouring the transfer of plasma proteins of low molecular weight. — From a comparative study of hepatic lymph and plasma, it was concluded that the molecular sieve process was completed by the time the plasma proteins reached the interstitial fluid. The sieving membrane was therefore assigned anatomically to the vascular walls, which were found to have the properties of an isoporous membrane with a pore radius of 102 Å. No further molecular sieving was found to take place during the crossing of the second barrier between blood and bile,viz.the epithelial sheet separating interstitial fluid from the

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02341.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract.In order to determine whether increased plasma free fatty acid (FFA) levels inhibit glucose utilization in man, glucose metabolism was studied in 8 normal subjects both under basal conditions and during experimental elevations of plasma FFA concentrations induced by the administration of high fat meals and heparin. A primed constant infusion of 1‐14C‐glucose was used to measure the rate of turnover, the fractional removal rate and the rate of oxidation of plasma glucose under both experimental conditions. Elevations of FFA levels (+117%) were accompanied by a 9% reduction in both the fractional removal rate of glucose and the hepatic glucose production so that glycaemia remained unchanged. The % glucose converted to CO2, and the % CO2derived from plasma glucose decreased respectively by 13.5% and 21.7%, while unlabelled CO2production remained unchanged. This reduction in glucose utilization occurred despite a significant rise in insulin concentration indicating that high FFA levels reduce sensitivity to insulin. The tissue implicated in the inhibitory effect of FFA on overall glucose utilization cannot be determined from these experiments but it is suggested that muscle participated in these metabolic changes. These data provide further arguments supporting the view that plasma FFA participate in the regulation of glucose metabolism in

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02342.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract.Sodium dodecyl sulphate—acrylamide gel electrophoresis (SDS‐AGE) separates proteins according to their molecular weight (MW) without being influenced by their electrostatic charge. It was carried out on the urine of 17 healthy control subjects and 92 ambulatory patients with suspected or known renal impairment. The SDS‐AGE patterns were classified as physiological, low MW predominance, middle MW predominance, high MW predominance, or mixed low and high MW. Patients were separately classified as having either normal kidneys or glomerular, tubular or mixed renal lesions according to the results of clinical investigation. Comparison of both classifications revealed that SDS‐AGE allowed a correct diagnosis of the site of renal involvement in 83 per cent of cases. Predominantly low MW protein excretion correlated with tubular damage. Middle and high MW patterns correlated with glomerular disease, and a relationship between nephrotic syndrome with minimal glomerular changes and middle MW pattern was found in two cases, suggesting that SDS‐AGE could be used to evaluate the selectivity of proteinuria. However, the estimation of selectivity by SDS‐AGE should be studied in a sufficient number of cases and compared with measurements of selectivity by the protein clear

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02343.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract.Using pH‐microelectrodes the excretion of hydrogen‐ions and bicarbonate in relation to flow rate was investigated in a single sweat gland of cystic fibrosis children.The results show decreased excretion of hydrogen‐ions and an increased excretion of bicarbonate. Evidence is presented that due to reduced secretion of hydrogen‐ions in the duct both the reabsorption of sodium and the secretion of potassium may be impaired.The possibility is discussed that reduced flux of hydrogen‐ions may similarly be responsible for the excretory defect in the duct system of the pancreas.Reduced flux of protons across the luminal membrane of epithelial cells is proposed as a general feature of exocrine gland defects. It is then possible to describe both the cationic transport defect of the sweat gland duct and the anionic bicarbonate‐secretory defect

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02344.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstract.The dynamics of the insulin response to intravenously administered glucose were studied in man. It was shown that (a) insulin response to prolonged stimulation is biphasic; (b) if the glucose stimulus is repeated with short intervals, inhibition of the second response occurs; (c) if longer time‐intervals are used, enhancement of the response is noted at the second stimulation. These findings suggest that when the pancreatic islets are exposed to hyperglycaemia, three kinetically distinct phenomena are initiated. Glucose induces almost instantaneous initiation of insulin release. Shortly thereafter, the pancreas enters a refractory phase. Thirdly, and at a later stage, a state of potentiation is built up in the islets. The effect of glucose on insulin synthesis is not considered here.—Against this background, and based on an earlier model, a mathematical model for the analysis of the glucose‐insulin interplay during glucose infusions was constructed. The model describes the eventual occurrence of glucosuria, changes in the concentration of glucose in its pool, and mimics the effects of regulatory hormones when hypo‐glycaemia appears. Insulin secretion is assumed to be controlled, in a multiplicative manner, by an immediate glucose function, a hypothetical potentiator that is slowly generated by glucose, and a negative factor with a shorter time‐course which corresponds to the refractory phase of the pancreas. A three compartment model is used in the simulation of the metabolism and distribution of insulin after its release. Finally, glucose utilization is described as a multiplicative function, related to the prevailing concentrations of glucose in blood and insulin in the extracellular space.—This model is able to simulate all the experimental situations described in this report, both in normal man and in the diabetic syndrome, in which insulin secretion shows varying degrees of impairment. The results of the simulation of individual experiments are given either as a set of theoretical parameter values, or described as the insulin response of the model to a standard, hypothetical glucose stimulus. The latter alternative is an attractive method for objectively evaluating the insulin response to a standard glucose load in clinica

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02345.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Summary.Bacterial overgrowth in the small bowel has been recognised in 11 patients with the aid of the breath‐test with [glyco‐1‐14C] cholic acid and by the determination of the amount of bacteria in the jejunal juice. In all but one patient hypoalbuminaemia, from 21.9 to 42.9 g/1, was observed. This low level of serum albumin can be due to an excessive intestinal protein‐loss or to a decreased rate of synthesis of albumin as the result of an insufficient delivery of amino acids to the liver. In 11 patients with bacterial overgrowth the rate of synthesis of albumin has been determined by the14C‐carbonate method. Compared to a control group the rate of albumin synthesis and the serum level of valine, leucine, lysine and tryptophan were significantly decreased in the patients with bacterial overgrowth. A positive correlation was found between the rate of albumin synthesis and the serum levels of valine, isoleucine, leucine and tryptophan. When the serum levels of these 4 essential amino acids were low, the rate of albumin synthesis was

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1974.tb02346.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY