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W F Caspary

Publications and source records attributed to W F Caspary.

At least 163 records · Page 9Linked to original sources
PubMed1994

Lack of accuracy of plasma alpha-amino nitrogen profiles as an indicator of exocrine pancreatic function both after continuous and bolus stimulation of the pancreas with secretin and cholecystokinin-pancreozymin.

BACKGROUND: The reduced decrease of plasma alpha-amino nitrogen after hormonal stimulation of the pancreas has been characterized as a valid and simple test of pancreatic function. Aim of this study was to reassess the clinical value of the alpha-amino nitrogen test and to evaluate the role of different modes of hormonal secretion. Therefore, we have investigated the relationship of plasma alpha-amino nitrogen responses and pancreatic secretion, stimulated by either bolus injection (n = 25) or continuous infusion (n = 32) of cholecystokinin-pancreozymin in patients with and without exocrine pancreatic insufficiency as determined by the secretin-pancreozymin test. Of the 57 patients referred to the secretin-pancreozymin-test, 18 had pancreatic insufficiency, each 9 in the group with continuous and bolus stimulation. RESULTS: Basal alpha-amino nitrogen concentrations were almost identical in patients with and without impaired pancreatic function (2.66 +/- 0.12 mmol/l vs. 2.73 +/- 0.08 mmol/l [SEM]; p > 0.05). Both, the bolus dose and infusion of cholecystokinin induced similar (log-normally distributed) maximum decreases of alpha-amino nitrogen concentrations (-SD; mean; + SD: 3.6; 9.0; 22.3% vs. 6.0; 10.5; 18.5%, respectively) in the patients without exocrine pancreatic insufficiency. This was in tendency more pronounced compared to those with impaired pancreatic secretion (cholecystokinin bolus; 2.7; 5.2; 9.9%; infusion: 5.0; 7.7; 11.6%). The difference (+/- exocrine pancreatic insufficiency) was significant (p < 0.05) for the infusion mode only. Moreover, the time course of alpha-amino nitrogen concentration-profiles was more homogenous after hormone infusion as compared to bolus stimulation. Sensitivities to detect exocrine pancreatic insufficiency by the alpha-amino nitrogen test were < 50% with either test modification. CONCLUSION: The decrease of plasma alpha-amino nitrogen after stimulation with cholecystokinin is no accurate indicator of exocrine pancreatic function, regardless of whether hormonal stimulation is by bolus or by infusion.

Adult↗
PubMed1994

Preparation of basolateral membrane vesicles from rat enterocytes: influence of different gradient media.

An attempt was made to assess whether the choice of the gradient media could influence the yield of basolateral membrane vesicles isolated from the rat intestine as well as their functional characteristics. Crude membranes prepared in the same way were therefore centrifuged with 10% Percoll, on a discontinuous sucrose gradient or on a continuous sorbitol gradient. The protein yield was significantly higher with the Percoll gradient than with sucrose and sorbitol gradient centrifugation (2.7 +/- 1.0%; 0.4 +/- 0.1%; 0.6 +/- 0.2%, respectively). Enrichment in Na+,K+-ATPase was similar in all three preparations (8.50 +/- 2.34; 8.22 +/- 4.78; 8.20 +/- 2.08). However, contamination with brush border membranes was significantly higher after Percoll gradient centrifugation and negligible after the use of the other two gradient media. Transport of D-glucose in the BLM prepared by Percoll gradient centrifugation also indicated some contamination with functional brush-border membranes. An attempt to purify basolateral membrane vesicles after Percoll gradient centrifugation with Ca2+ precipitation, however, reduced the protein yield to less than 1%. We conclude that in the preparation of basolateral membrane vesicles from the rat enterocytes each of the gradient media may have certain advantages and disadvantages, which should be considered according to the purpose of the preparation.

Animals↗
PubMed1994

More convenient 13C-urea breath test modifications still meet the criteria for valid diagnosis of Helicobacter pylori infection.

AIMS AND METHODS: 13C-Urea breath tests (UBT) were performed in 217 patients with epigastric symptoms to assess (a) the validity of shorter intervals of breath sample collection and (b) of the non-fasting state on diagnosing H. pylori infection and to evaluate (c) a more simple sampling method. (a) In 186 patients, breath samples were taken before and at 10, 20, 30, 40, 50, 60, 90, and 120 minutes after ingestion of 75 mg 13C-urea. 13C-enrichment was measured by isotope ratio mass spectrometry [delta/1000] and the cumulative recovery rate (CRR) was calculated. (b) 31 patients performed 13C-UBTs on two occasions, i.e. fasted and in the postprandial state collecting breath before and 30 min after substrate ingestion. (c) 61 breath samples were obtained in duplicate, i.e. both with an aluminium foil breath bag using evacuated glass tubes, and by exhalation into open vials via straw. RESULTS: (a) DOB-responses at 10, 20, 30, and 40 minutes after dose showed a linear correlation with the 120 min-CRR. Referring to a CRR > 3% at 120 min (criterion of H. pylori-infection), DOB-responses at 20 min with a cut off-value at 5/1000 (ROC-analysis) were shown to be valid for diagnosing H. pylori status in man (sensitivity 99.0%, specificity 100%). (b) Postprandially, mean DOB-responses of H.pylori positive patients were lower than in the fasting state (17.46/1000 vs. 27.63/1000; p < 0.01). With the cut-off at 5/1000, however, sensitivity still was 94.4% and specificity was 100%. (c) The straw and breath bag method gave equivalent results (r = 0.98, p < 0.0001). CONCLUSIONS: (a) A two sample measurement using the DOB at 20 min and a cut-off value of 5/1000 can replace the CRR-calculation over 120 minutes. (b) Although quantitative DOB-responses are significantly affected, 13C-UBT can be performed in the postprandial state with no significant effect on the detection of the H. pylori infection. (c) The sample collection by a simple straw method meets precision requirements < 1.5 delta/1000. Thus, the 13C-UBT can be performed cheaper, faster and more conveniently.

Adult↗
PubMed1994

Reduced postheparin plasma diamine oxidase activity in patients with chronic renal failure.

The intestinal mucosa plays a fundamental role as the site for absorption of nutrients, and as an important barrier against potentially harmful agents in the gastrointestinal lumen. The functional integrity of the small bowel in patients with chronic renal failure was measured by post-heparin-diaminoxidase (DAO) activity in a low and safe dose of heparin (5000 IU) in patients with chronic renal failure participating in a hemodialysis program. The results of the study provide one of the first observations about a diminished DAO-response in patients with chronic renal failure reflecting a mucosal abnormality in these patients which has to be further characterized. Our findings also show that this reduced DAO activity is not caused by the effect of uremic toxins. These results further show that a smaller and safer i.v. dose of heparin (5000 IU or less) will release DAO activity as reliably as high doses used by others. We therefore conclude that postheparin DAO activity might be used as a new noninvasive test reflecting intestinal function in patients with chronic renal failure.

Adult↗
PubMed1993

A synthetic peptide of the effector domain of rab3A stimulates inositol 1,4,5-trisphosphate production in digitonin-permeabilized pancreatic acini.

In this study we report that a synthetic peptide of the effector domain of rab3A (rab3AL(33-48)) stimulates both amylase secretion and inositol 1,4,5-trisphosphate (IP3)-accumulation in digitonin-permeabilized pancreatic acini in an analogous way to cholecystokinin-octapeptide (CCK8). Maximum CCK8-induced IP3-accumulation was observed at five seconds after addition of CCK8 to the acini. Maximum rab3AL(33-48)-induced IP3-production occurred 15 to 30 seconds after addition of rab3AL(33-48); then the acinar IP3 content declined towards the basal level. Heparin, an inhibitor of IP3 binding to its receptor, inhibited both rab3AL(33-48)- and CCK8-stimulated amylase secretion without affecting the response to vasoactive intestinal polypeptide. rab3AL(33-48) had no effect in intact acini, indicating that the site of action of rab3AL(33-48) is intracellular. We conclude that rab-like small molecular weight GTP-binding proteins regulate phospholipase C activity and thereby amylase secretion from inside of the cell.

Amylases↗
PubMed1993

Effect of epidermal growth factor on cholecystokinin-induced amylase release and inositol 1,4,5-trisphosphate production in pancreatic acinar cells.

In the present study we investigated the role of epidermal growth factor (EGF) in cholecystokinin-octapeptide (CCK8)-induced inositol 1,4,5-trisphosphate (IP3) production and amylase release. The data show that high EGF concentrations (90 nM) increased the basal amylase release, but did not increase the acinar IP3 content. High EGF concentrations shifted the dose-response curve for CCK8-induced amylase release to lower CCK8 concentrations, whereas low EGF concentrations (17 nM) shifted this dose-response curve to higher CCK8 concentrations. 17 nM EGF inhibited CCK8-induced IP3 production during the whole period of observation of 5 min, whereas 90 nM EGF inhibited only the initial component (15 s) of CCK8-induced IP3 production. At later time points, 90 nM EGF increased CCK8-induced IP3 production. We conclude that low concentrations of EGF are inhibitory on CCK8-induced IP3 production and amylase release, whereas high EGF concentrations stimulate CCK8-induced amylase release.

Amylases↗
PubMed1993

Effects of guanine nucleotides on bombesin-stimulated signal transduction in rat pancreatic acinar cells.

To study the role of guanine nucleotide binding proteins (G proteins) in bombesin receptor signal transduction, we investigated the effects of guanine nucleotide analogues and of the G protein activator NaF on bombesin-induced amylase release, inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) production and release of intracellular Ca2+ in rat pancreatic acini. In digitonin-permeabilized acini, guanosine 5'-[gamma-thio]triphosphate (GTP gamma S), a well-known activator of G proteins, potentiated bombesin-induced Ins(1,4,5)P3 production and increased amylase release at low bombesin concentrations (< 10 nM). By contrast, GTP gamma S decreased bombesin-stimulated amylase release at high bombesin concentrations (> 10 nM). Fluoride (10 mM), another G protein activator, had similar effects to GTP gamma S on amylase release. However, unlike GTP gamma S it had no effect on Ins(1,4,5)P3 production and release of intracellular Ca2+ induced by high bombesin concentrations. GDP and its analogues, such as 2'-desoxyguanosine 5'-diphosphate (dGDP) or guanosine 5'-[beta-thio]diphosphate (GDP beta S), inhibit activation of G proteins. GDP and dGDP both inhibited amylase release and Ins(1,4,5)P3 production at all bombesin concentrations tested. In contrast, GDP beta S mimicked the effects of GTP gamma S on bombesin-stimulated amylase release and Ins(1,4,5)P3 accumulation. In conclusion, we suggest that bombesin receptor-mediated signal transduction involves G proteins in pancreatic acini. The correlation between inhibition of maximum-stimulated enzyme secretion and further increase in Ins(1,4,5)P3 production in response to GTP gamma S at high bombesin concentrations suggests that overstimulation of phospholipase C inhibits amylase release. The discrepant effects of GDP and of GDP beta S on phospholipase C activity and amylase release might be due to the ability of GDP beta S, but not of GDP to activate G proteins persistently after phosphorylation by G protein-associated GDP kinases.

Amylases↗
PubMed1993

Early changes of body composition in human immunodeficiency virus-infected patients: tetrapolar body impedance analysis indicates significant malnutrition.

Total body water, body fat, body cell mass (BCM), extracellular mass (ECM), and the ECM-BCM ratio by impedance analysis were determined in 193 human immunodeficiency virus (HIV)-infected patients and 340 control subjects. Walter Reed (WR) classification was WR 2 in 26, WR 3-5 in 85, and WR 6 in 82 patients. Whereas resistance was increased, reactance and the phase angle were significantly reduced in all patient groups. Neither body weight nor body mass index (BMI) was affected in WR 2 patients, but BCM was reduced (31.9 +/- 4.3 vs 35.8 +/- 7.3 kg, P < 0.007) and ECM (31.2 +/- 4.4 vs 28.8 +/- 3.8 kg) as well as ECM-BCM ratio increased (0.99 +/- 0.14 vs 0.83 +/- 0.16, P < 0.001). In contrast to WR classification, diarrhea did not correspond with malnutrition. A loss of BCM (malnutrition) occurred already in otherwise symptomless HIV-infected patients (WR 2). This effect can be measured by tetrapolar impedence analysis but not by body weight or BMI.

Adult↗
PubMed1993

Intestinal absorption and malnutrition in patients with the acquired immunodeficiency syndrome (AIDS).

The relation of small intestinal dysfunction and malnutrition (body composition and serum index parameters of nutrition) was investigated in 36 male patients with AIDS. Mucosal absorptive capacity was assessed by the 25 g D-xylose test. D-xylose absorption (2 h - serum profile and 5 h - urine) classified 17 patients as having impaired and 19 patients as having normal absorption. In both groups body weight, body mass index as well as body composition analysis indicated malnutrition when compared to healthy male controls (n = 340) or asymptomatic HIV-infected patients (n = 26). Patients with abnormal D-xylose test had more severe malnutrition indicated by a lower body cell mass (17.7 +/- 5.4 vs. 22.5 +/- 4.5 kg; p < 0.01) and an increased ratio of extracellular mass to body cell mass (1.99 +/- 0.82 vs. 1.45 +/- 0.46 p < 0.01). Total serum protein, albumin, cholinesterase activity, cholesterol and LDL were significantly diminished in AIDS-patients with abnormal D-xylose test compared to those with normal D-xylose absorption. Intestinal dysfunction indicated by decreased D-xylose Intestinal dysfunction indicated by decreased D-xylose absorption thus represents an important feature of malnutrition and wasting, and patients with abnormal D-xylose absorption have more profound impairment of body composition, visceral proteins and lipids reflecting malnutrition than patients with unaffected intestinal absorption.

AIDS-Related Opportunistic Infections↗
PubMed1992

Simple and rapid method for determination of short-chain fatty acids in biological materials by high-performance liquid chromatography with ultraviolet detection.

A new and versatile method for the identification and quantification of short-chain fatty acids, such as formic, acetic, propionic, butyric, isobutyric, valeric, isovaleric and mercaptoacetic acids, in biological specimens by high-performance liquid chromatography is described. After sample purification by vacuum transfer and concentration by alkaline freeze-drying, the acids were measured without any further preparative step, using a sulphonated polystyrene-divinylbenzene column as stationary phase. Ultraviolet detection of the native acids was done at 214 nm. Peak resolution and reproducibility were as good as with gas chromatography. Many examples of the application of this method to a variety of biological specimens and fluids both from the rats and humans are described.

Animals↗
PubMed1992

Physiology and pathophysiology of intestinal absorption.

Final digestion and absorption of carbohydrates (CHO) occur after intraluminal hydrolysis by pancreatic alpha-amylase at the surface of the mucosal membrane in close relationship between disaccharide hydrolysis and the glucalogue carrier system. In general, Na(+)-dependent transport is the rate-limiting step of CHO absorption. The rate of absorption is determined by mode of ingestion, chemical composition of the meal, gastric emptying, pancreatic digestion, intestinal digestion and absorption, and intestinal motility. A delay of absorption of CHO may be achieved by dietary fibers, alpha-amylase inhibitors, or alpha-glucosidase inhibitors. Final protein digestion is achieved by a dual mechanism: intact peptide absorption with subsequent intracellular hydrolysis to free amino acids (AA) and membrane hydrolysis of peptides followed by absorption of free AA. More complex is the mechanism of lipid absorption: emulsification, lipolysis, micellar formation, membrane translocation, intracellular resynthesis, chylomicron formation, and lymphatic drainage. The most critical steps in lipid digestion are lipolysis and micellar formation.

Dietary Carbohydrates↗
PubMed1992

Characteristics of putrescine uptake by human brush border membrane vesicles.

Both putrescine and the polyamines spermidine and spermine are essential factors for growth and differentiation in all cells of higher eucaryotes. In principle, increased requirements of polyamines in mucosal cells either can be met by de novo-synthesis or by increasing the uptake from lumen (brush border membrane) or bloodstream (basolateral membrane). We therefore evaluated putrescine uptake in intestinal mucosal cells by using human brush border membrane vesicles (BBMV). Intravesicular uptake of putrescine was shown by osmoplots. This process was not saturable over a substrate range from 1 to 80 microM. Putrescine transport was also found to be independent of temperature (Q10 = 1.23). No differences in putrescine uptake rates were found in the presence or absence of Na+, and there was no evidence for any dependence of putrescine uptake from other cations. Our data indicate that putrescine uptake by human intestinal brush border membrane vesicles occurs by passive diffusion. It is concluded that a formerly described saturable and carrier mediated uptake in isolated intestinal mucosal cells from different species is probably influenced by active transport across the basolateral membranes. Therefore, further studies with isolated basolateral membranes are advocated.

Cell Membrane↗
PubMed1992

Delayed activation of D-glucose transport in type II diabetes mellitus.

Peripheral insulin resistance is suggested to play an important role in the pathogenesis of type II diabetes mellitus. In this study we investigated insulin receptor binding, D-glucose transport under equilibrium conditions for insulin and the activation kinetics of insulin stimulated D-glucose transport in isolated human adipocytes from type II diabetics and healthy controls. While the insulin receptor binding affinity was not significantly different between both groups, basal and insulin stimulated glucose transport rates were reduced in adipocytes from type II diabetics compared to normal controls. The activation of D-glucose transport was significantly delayed in the diabetics, the time to achieve maximal transport rates was 7.7 +/- 1.1 vs. 4.2 +/- 1.4 min, respectively (p < 0.05). Thus a reduced velocity of glucose transport activation by insulin appears to be a further factor contributing to peripheral insulin resistance in type II diabetics.

Biological Transport↗
PubMed1992

[Anal incontinence in patients with Addison's disease: a gluco- and mineralocorticoid independent sphincter malfunction?].

Anorectal motor function was evaluated in 15 female patients with Addison's disease and androgen deficiency and 15 age-matched healthy volunteers. Medical history revealed symptoms of faecal incontinence in 5 patients. The patients showed decreased maximum retention volumes (p less than 0.01) in the rectal saline infusion test. Lowered anal sphincter resting (p less than 0.01) and squeeze pressure (p less than 0.01) was demonstrated in patients with adrenocortical insufficiency. No differences between patients and controls were found in respect of perception volume, minimal distension volume for sphincter relaxation and rectal compliance by means of intrarectal balloon distension. Electromyography of the external anal sphincter was performed in 8 patients and showed no evidence for a neurogenic defect. Relevant morphological changes of the anorectum could be excluded endoscopically in 13 of the 15 patients. Therefore impaired anorectal muscular function is responsible for faecal incontinence in patients with Addison's disease and androgen deficiency. Further investigations will show, whether these findings are the consequence of lowered androgen production.

Addison Disease↗