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Biomedical subjects

H Ditschuneit

Publications and source records attributed to H Ditschuneit.

At least 127 records · Page 7Linked to original sources
PubMed1986

[Sonography of gallbladder calculi: possibilities and limits in the selection of gallstone patients suitable for conservative lysis].

The sonographic patterns of artificially produced pure cholesterol and pigment gallstones were evaluated in vitro. Cholesterol calculi exhibited a smooth echo with a relatively high beam penetration, whereas pigment calculi showed a sickle-like surface echo without beam penetration. Clinical evaluation of these criteria in 107 patients was based on correlating preoperative sonographic diagnosis with postoperative microchemical analysis of the calculi. Although small, smooth cholesterol calculi were detected via ultrasound with an accuracy of more than 90 percent, pigment calculi could not be separated and identified with satisfactory precision.

Adult↗
PubMed1986

Effect of pentagastrin, secretin and cholecystokinin on growth and differentiation in organ cultured rabbit small intestine.

The effect of pentagastrin, secretin and cholecystokinin on biochemical parameters of mucosal growth and differentiation was studied in organ cultured rabbit jejunum and ileum. Pentagastrin at 0.05-5.0 microgram/ml did not affect DNA content of the biopsy, but led to a significant decrease of sucrase and alkaline phosphatase activity in the ileum. Secretin prompted a significant decrease of DNA and protein in the ileum at a level of 10(-7) and 10(-5) M, but had no effect in the jejunum. Of the brush border enzymes, sucrase and alkaline phosphatase were suppressed in both parts of the intestine both with respect to specific activity and total biopsy content. Cholecystokinin, like pentagastrin, did not influence DNA or protein content, but reduced sucrase, maltase and alkaline phosphatase activity. HMG-CoA reductase, the key enzyme of cholesterol synthesis, was not significantly affected by any of the three hormones tested. When brush border enzymes or DNA from desquamated cells were measured in the post-culture medium, no consistent effect of any gastrointestinal hormone was apparent. The present study demonstrates a direct "antitrophic" effect of secretin in cultured mucosa. Pentagastrin and cholecystokinin did not influence mucosal DNA content in vitro but apparently inhibited villus cell differentiation.

Animals↗
PubMed1986

Prostaglandins are not involved in the differentiation or growth of cultured small intestinal cells.

Prostaglandins have been reported to exert trophic effects on gastrointestinal tissues. To determine whether there is a direct interaction with enterocytes, prostaglandins PGE2, PGF2 alpha, PGA2, PGB2 and the stable PGE2 derivative suleprost as well as the prostacyclin derivative nileprost were tested in rabbit ileal mucosa under organ culture conditions. At concentrations between 10(-9) and 10(-5) M, none of the prostaglandins significantly affected biopsy DNA or protein content, or the activity of the brush border enzymes alkaline phosphatase, lactase, sucrase or maltase. The inhibition of endogenous prostaglandin synthesis with indomethacin also failed to alter these parameters. Moreover, the growth rate of a rat duodenal crypt cell line was unaffected when cultured in the presence of PGE2, PGF2 alpha or indomethacin. Thus, there was no evidence for a direct effect of exogenous or endogenous prostaglandins or their deficiency on the differentiation or growth in cultured small intestinal cells.

Animals↗
PubMed1986

Radioimmunoassay for the measurement of insulin-like growth factor I in patients with pituitary disease in comparison with commercially available somatomedin-C radioimmunoassays.

A highly sensitive and specific radioimmunoassay for the measurement of insulin-like growth factor I (IGF I) has been developed. The IGF I concentrations were measured in sera of normal subjects, patients with acromegaly, hypophysectomized patients and patients with hyperprolactinaemia. The results were compared with the results obtained after measurement of IGF I in the sera of the same patients with two commercially available radioimmunoassays for somatomedin-C. IGF I was separated from its carrier protein using Sep-Pak C18 cartridges. The total recovery of IGF I by this method was about 100%. The in-house assay shows a high specificity for IGF I and a high sensitivity. As little as 0.1 microgram/l of IGF I can be detected. Only a small amount of serum (25 microliter) is necessary for the IGF I determination and a great number of serum samples (more than 100 per day) can be processed. The mean immunoreactive IGF I concentration was 379 +/- 159 micrograms/l in normal adult subjects, 3340 +/- 1094 micrograms/l in acromegalic patients, and 52 +/- 11 micrograms/l in growth-hormone deficient patients. Patients with hyperprolactinaemia had an IGF I concentration of 433 +/- 112 micrograms/l.

Humans↗
PubMed1986

Prostaglandin biosynthesis in gastroduodenal mucosa: methodological difficulties and their implications.

A deficiency of locally synthesized prostaglandins has been suggested to underly gastric and duodenal ulcer disease and to mediate the mucosal lesions induced by non-steroidal anti-inflammatory drugs. The exact definition of their role is hampered by various methodological problems. First, the mucosal content of prostaglandins is affected by mechanical manipulation and homogenization and does not correspond to the rate of synthesis. Secondly, the assay of this rate in mass terms is also susceptible to these artefacts, and a steady state of prostaglandin secretion in vitro is usually not achieved. Thirdly, if prostaglandin synthesis is measured in vitro by the incorporation of labelled arachidonic acid, the possibly rate-limiting role of substrate supply is not taken into account. Thus, it is likely that a part of the disagreement in the field stems from the problems in measuring the true rates of prostaglandin synthesis in vivo.

Animals↗
PubMed1986

Exocrine pancreatic function in correlation to ductal and parenchymal morphology in chronic pancreatitis.

A prospective investigation of the diagnostic value of imaging procedures, computed tomography (CT) and endoscopic retrograde pancreatography (ERP) in comparison with the exocrine pancreatic function test, was done in 109 patients with chronic pancreatitis. The sensitivity of the secretin-ceruletide test (SC) proved to be 87% as compared with 89% for ERP and 78% for CT. The severity of morphological lesions noted in ERP and CT, shows a significant correlation to the degree of the exocrine functional impairment (p less than 0.001). 75% of patients with chronic pancreatitis had corresponding functional and ductal changes in advanced-stage disease, while only 47% of the patients with severe pancreatic insufficiency had CT changes of a corresponding degree. ERP lesions such as ductal obstruction and marked duct dilatation, and CT alterations such as atrophy and ductal dilatation, are almost always coupled with severe pancreatic insufficiency in chronic pancreatitis. Calcific lesions demonstrated by CT are also found in less advanced stages of exocrine insufficiency. Discrepancies between functional and morphological alterations were remarkable in "early" stages of the disease.

Adult↗
PubMed1985

Regulation of insulin binding and glycogenesis by insulin and dexamethasone in cultured rat hepatocytes.

Regulation of insulin-binding and basal (insulin-independent) as well as insulin-stimulated glycogen synthesis from [14C]glucose, net glycogen deposition and glycogen synthase activation by insulin and dexamethasone were studied in primary cultures of adult rat hepatocytes maintained under chemically defined conditions. Insulin receptor number was increased in a dose-dependent fashion by dexamethasone added to the medium between 24 and 48 h of culture and reduced by insulin, whereas ligand affinity remained unaltered. Insulin-induced down-regulation of insulin receptors was not affected by the glucocorticoid. Although the changes in the sensitivity to insulin of glycogen synthesis from glucose and net glycogen deposition paralleled the modulation of the number of insulin receptors, postbinding events appear to be implicated also in the regulation of insulin-sensitivity. Alterations of the responsiveness of glycogen synthesis to insulin caused by the glucocorticoid and/or insulin and by variation between individual rats were inversely related to cellular glycogen contents, suggesting that hepatocellular glycogen content participates in the regulation of insulin-responsiveness of this metabolic pathway. Regulation of insulin-dependent glycogen synthesis were different. Since the effects of this 'physiological' increase in exogenous glucose were small compared to the acute action of insulin, insulin rather than portal venous glucose is considered to represent the prime stimulator of hepatic glycogen synthesis.

Animals↗
PubMed1985

[Histological and ultrastructural findings in the healing phase of duodenal ulcer].

To evaluate and further characterize duodenal ulcer healing macroscopical, histological, and ultrastructural criteria were examined in 24 patients with active duodenal ulcer disease under two different treatment schedules. After the endoscopic confirmation of an active duodenal ulcer patients were randomly assigned to treatment with either an antacid (group A) or with an H2 blocker (group B). Tissue specimen were taken during endoscopy from the margin and 1 cm from the ulcer before therapy and from the ulcer scar or the previous ulcerated region after a 4 week treatment. A macroscopic ulcer healing by endoscopic criteria was confirmed in 83% of the patients in group A and in 83% of group B. The prominent histological feature of duodenal ulcer healing was a significant increase of PAS positive epithelial cells. Ultrastructural changes of the duodenal mucosa were still present at the end of the treatment, even in the presence of complete macroscopic healing. The ultrastructural healing process shows constant patterns independent from the type of treatment. The characteristic morphological feature by electron microscopy of the healing duodenal ulcer is the appearance of a metaplastic mucus secreting cell of the antrum-type. The devastated mucous structure during the ulcerative phase regains the normal net-like structure after 4 weeks therapy.

Adult↗
PubMed1985

Rapid and accurate reversed-phase high-performance liquid chromatographic determination of conjugated bile acids in human bile for routine clinical applications. Therapeutic control during gallstone dissolution therapy.

This paper introduces a new method to detect the taurine and glycine conjugates of five different bile acids (cholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid and lithocholic acid) in human bile. Advantages of this method are sufficient separation of compounds within a short period of time and a high rate of reproducibility. Using a mobile phase gradient of acetonitrile and water, modified with tetrabutylammonium hydrogen sulphate (0.0075 mol/l), we were able to maximize the differentiation between ursodeoxycholic acid and lithocholic acid, which is of primary interest during conservative gallstone dissolution therapy. Use of this gradient reduced analysis time to less than 0.5 h. Recovery rates for this modified method ranged from 94% to 100%, and reproducibility was 98%, sufficient for routine clinical applications.

Bile↗
PubMed1985

[Clinical relevance of immunochemical determination of pancreatic lipase in chronic pancreatitis].

The determination of basal pancreatic serum enzymes is of little value in the diagnosis of chronic pancreatitis. The organ specificity of a recently introduced immunochemical method of determining pancreatic lipase is guaranteed. The diagnostic value of the basal and stimulated serum-lipase determination by the immunochemical assay in chronic pancreatitis was investigated on 84 patients and controls. In 46 patients with chronic pancreatitis the serum increase of pancreatic lipase after secretin stimulation (1 U/kg) was significantly (P less than 0.01) higher than the pancreatic lipase increase in patients with non-pancreatic intestinal disorders and in healthy controls. Patients with chronic pancreatitis deserve to be classified in subgroups, according to the degree of the exocrine pancreatic insufficiency established by means of the secretin-ceruletide test. Of the patients with chronic pancreatitis and a slight to moderate exocrine pancreatic insufficiency 87% show an abnormal serum pancreatic-lipase increase and differ significantly (P less than 0.01) from patients with severe exocrine insufficiency who exhibit an increase of the pancreatic serum lipase only in exceptional cases. Specificity is limited, since an abnormal serum lipase increase after stimulation is found in 20% of controls.

Adolescent↗
PubMed1985

Ultrasound characteristics of the pancreas in children with cystic fibrosis.

Eighteen patients (3 months to 16 years) with cystic fibrosis (CF) were examined with a real-time mechanical sector-scanner (5 MH transducer). Compared with age-matched controls, each CF patient showed morphologic changes in the pancreas on abdominal ultrasound examination. A very common finding was a decrease in organ anterior-posterior diameters (CF versus controls: head, 1.25 +/- 0.38 cm versus 2.44 +/- 0.39 cm; body, 0.56 +/- 0.35 cm versus 0.98 +/- 0.3 cm; tail, 0.83 +/- 0.28 cm versus 1.81 +/- 0.38 cm) and a pronounced, age-independent increase in tissue echogenicity. In younger patients, small cystic degenerations could be observed in the pancreatic tail. No correlation could be found between ultrasound morphology, especially pancreatic duct imaging, and exocrine pancreatic function.

Adolescent↗
PubMed1985

Fenofibrate treatment inhibits HMG-CoA reductase activity in mononuclear cells from hyperlipoproteinemic patients.

The effect of fenofibrate treatment on serum cholesterol levels was studied in relation to the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase in mononuclear cells from patients with hyperlipoproteinemia type IIa and IIb. When patients who had received fenofibrate (300 mg/day) for at least 8 weeks were given placebo during a subsequent 2-months period, both serum cholesterol concentration and mononuclear cell HMGR increased significantly in both types IIa and IIb. After reinstitution of fenofibrate treatment both parameters gradually declined and returned close to the initial level after another 28 weeks. It is concluded that a part of the lipid-lowering action of fenofibrate may be due to an inhibition of cholesterol synthesis.

Adult↗
PubMed1985

[Ultrasonically targetted fine-needle aspiration cytology in the immediate postoperative follow-up of transplanted kidneys].

From March 1982 to September 1983 62 ultrasound-guided fine needle aspiration cytologies in 22 patients with cadaveric kidney transplants had been performed during the postoperative hospitalisation period. In any case it was possible to guide the needle tip into the cortico-medullary boundary or in sonolucent parenchymal areas occurring during acute cellular rejection episodes. Thus technical failures could be reduced to 6% (4 out of 22). In 79% the clinically suspected diagnosis could be confirmed by FNAC. Aspirates from circumscript sonolucent parenchymal areas allowed rejection diagnosis in 95%. In 17% cellular signs of rejection were seen cytologically despite a regular transplant function.

Adult↗
PubMed1985

Insulin-like growth factor I/somatomedin-C: a rapid isolation procedure with FPLC.

Insulin-like growth factor I (IGF I)/somatomedin-C (SM-C) was purified from lyophilized human serum by acid-ethanol extraction. The extract was precipitated with acetone-ethanol. The precipitate was purified by Sephadex G-50 chromatography. The protein peak within a molecular weight range of 5000-10 000 was further purified with FPLC-reversed phase chromatography using a Pep RPC HR 5/5 column (Pharmacia) with a solvent system of acetonitrile (CH3CN) and 0.1% trifluoroacetic acid (TFA) in water. The purification of IGF I was monitored by radioimmunoassay for SM-C. Purity was established by analytical isoelectric focusing and by SDS polyacrylamide gel electrophoresis. Analytical isoelectric focusing showed one single protein band with an apparent pI of 8.3 +/- 0.1. SDS polyacrylamide gel electrophoresis showed also one single protein band with an apparent molecular weight of 7000. Biological activity was demonstrated by measuring the (3H)thymidine incorporation into DNA of cultured arterial smooth muscle cells.

Acetone↗
PubMed1985

[Mucosa dimensions and cell proliferation in intestinal organ cultures with and without inhibition of cholesterol synthesis].

The changes in the structure and proliferative activity of rabbit ileal mucosa have been studied with morphometric and stathmokinetic techniques during 24 h organ culture. Under control conditions the villus base diameter and villus height decreased by 34 and 53%, respectively, whereas the number of villi per mm2 remained constant. The reduction of crypt depth was less pronounced than the loss in villus height, leading to a decrease in the villus height to crypt depth ratio from 3.4 to 2.3. The likely reason for this culture induced hypoplasia was a significant drop in mitotic activity as early as 2 h after starting the culture. Inhibition of HMG-CoA reductase, the key enzyme of cholesterogenesis, lead to a further reduction in mucosal dimensions and a near complete suppression of crypt cell regeneration. These data imply that despite the well-known preservation of differentiated function mucosal cell renewal during organ culture is impaired.

Animals↗
PubMed1985

Influence of extrapancreatic digestive disorders on the indirect pancreatic function test with fluorescein dilaurate.

The detection rate of pancreatic disease using the indirect pancreatic function test with orally administered substrate fluorescein dilaurate (FDL) was evaluated in 290 patients. The sensitivity of the test was 84% in chronic pancreatitis (99 patients). Results were abnormal in all 5 patients with advanced pancreatic cancer and in 3 of 19 patients tested after a single episode of acute pancreatitis. The specificity of the FDL test was 89% when healthy subjects or patients with functional gastrointestinal disorders served as controls. However, it dropped to 62% when all patients with different organic gastrointestinal disorders were considered. This decrease could be attributed to patients with subtotal gastric resection and extensive small bowel disease, who were found to have the highest of pathological FDL test results, i.e., 70 and 35%, respectively. Not restricting the oral FDL test to the detection of primary pancreatic disease, in subtotal gastrectomy and extensive small bowel disease this test provides the opportunity to detect secondary pancreatic dysfunction.

Adolescent↗