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Biomedical subjects

J Stadler

Publications and source records attributed to J Stadler.

At least 73 records · Page 4Linked to original sources
PubMed1991

Effect of high-fat and low-fiber meals on the cell proliferation activity of colorectal mucosa.

Normal healthy volunteers (n = 43) were divided into four groups that received diets providing low or high levels of dietary fat (33 or 96 g/day) and low or high levels of dietary fiber (6 and 41 g/day) for a period of five days. Proliferation was assessed with tritiated thymidine labeling of three rectal biopsies. After five days on the prescribed diets, the average thymidine labeling index (LI) of the group on the high fat-low fiber diet was only 25% higher than the average LI of the group on the low fat-high fiber diet, a difference that is not statistically significant. We conclude that a short-term increase in dietary fat and decrease in dietary fiber does not result in a large increase in cell proliferation rate.

Adult↗
PubMed1991

Nitric oxide and nitric oxide-generating compounds inhibit hepatocyte protein synthesis.

Hepatocytes are stimulated to produce nitric oxide (NO.) from L-arginine in response to conditioned Kupffer cell medium or a combination of cytokines. Associated with the production of NO.in hepatocytes, there is a profound decrease in total protein synthesis ([3H]leucine incorporation). This report demonstrates that authentic NO.and the NO.-generating compound S-nitroso-N-acetylpenicillamine inhibit hepatocyte total protein synthesis in a reversible and concentration-dependent fashion. In parallel with the suppression of hepatocyte total protein synthesis, authentic NO.inhibits the production of two specific hepatocyte proteins, albumin and fibrinogen, without influencing the quantity of albumin mRNA. Although authentic NO.induces a rapid increase in cGMP levels in hepatocytes, the addition of the cGMP analog 8-bromoguanosine 3':5' cyclic monophosphate to unstimulated HC cultures does not reproduce the inhibition of total protein synthesis. These data show that NO.is the hepatocyte L-arginine metabolite that inhibits protein synthesis. Furthermore, these findings indicate that NO.does not inhibit hepatocyte protein synthesis solely through the activation of soluble guanylate cyclase but appears to affect a translational or posttranslational process.

Albumins↗
PubMed1991

Effect of exogenous and endogenous nitric oxide on mitochondrial respiration of rat hepatocytes.

Although nitric oxide (.N = O) biosynthesis is inducible in rat hepatocytes (HC), the physiological significance of .N = O production by these cells is unknown. Short exposure of HC to authentic .N = O led to a concentration-dependent inhibition of mitochondrial aconitase, NADH-ubiquinone oxidoreductase, and succinate-ubiquinone oxidoreductase (complexes I and II of the mitochondrial electron transport chain). Most susceptible to .N = O inhibition was mitochondrial aconitase, in which a reduction in enzyme activity to 20.2 +/- 1.6% of control was observed. In contrast to mitochondrial aconitase, cytosolic aconitase activity was not inhibited by .N = O. After exposure to a maximal inhibitory concentration of .N = O, mitochondrial aconitase activity recovered completely within 6 h. Complex I did not fully recover within this incubation period. Endogenous .N = O biosynthesis was induced in HC by a specific combination of cytokines and lipopolysaccharide. After 18 h of incubation with these stimuli, a significant inhibition of mitochondrial aconitase activity to 70.8 +/- 2.4% of controls was detected. However, this was due only in part to the action of .N = O. A non- .N = O-dependent inhibition of mitochondrial function appeared to be mediated by tumor necrosis factor.

Animals↗
PubMed1990

Inducible cytosolic enzyme activity for the production of nitrogen oxides from L-arginine in hepatocytes.

The in vivo conditions needed for the induction of nitrogen oxide synthesis by hepatocytes were determined. Hepatocytes obtained from rats injected with killed Corynebacterium parvum spontaneously produced NO2(-)+NO3- in culture and were found to contain cytosolic enzyme activity for nitrogen oxide synthesis. The enzyme activity required both L-arginine and NADPH, and was not found in hepatocytes obtained from normal rats or rats injected with lipopolysaccharide (LPS) alone. In contrast, nonparenchymal cells were stimulated to synthesize NO2(-)+NO3- by LPS. These results show the presence of inducible cytosolic enzyme activity for nitrogen oxide synthesis in hepatocytes, which is distinct from nonparenchymal cell NO. synthesis.

Animals↗
PubMed1990

A rapidly reversible effect of a single dose of phenoxybenzamine on the fertility of male rats.

Male Sprague-Dawley rats received a single subcutaneous injection of phenoxybenzamine and each was allowed to mate with an untreated receptive female at 5, 29 or 53 h post-injection. At 5 h the number of males ejaculating was reduced and fertility virtually abolished; at 29 h all males ejaculated, but fertility was still low; at 53 h the performance of the males was normal.

Animals↗
PubMed1990

Long-term effects of dietary calcium on risk markers for colon cancer in patients with familial polyposis.

There is conflicting evidence regarding the benefit of calcium in prevention of colon cancer. Patients who have undergone ileorectal operations for familial polyposis can be useful to study hypotheses on prevention of colon cancer. In this study we evaluated the effect of long-term calcium supplementation on risk markers of colon cancer. Thirty-one patients with familial polyposis, after subtotal colectomy, were randomized to group A, which received placebo, and group B, which received 1200 mg of calcium daily. Intervention lasted 9 months, in which they underwent four 3-monthly evaluations that included food records, fecal pH, calcium and bile acids, and rectal biopsy for thymidine labeling. Age, height, weight, macronutrients, and dietary fiber were comparable in both groups. More women were in the group that received placebo. Fecal pH, weight, and bile acid levels were similar before intervention and remained unchanged. Fecal calcium levels were similar before intervention and increased in the calcium group throughout the study (p less than 0.05). Labeling index of placebo and calcium groups was similar before intervention (4.8 and 6.1, respectively). After 3 months it was reduced in both groups (3.1 and 4.4, respectively; p less than 0.05). After 6 months it was reduced only in the calcium group (3.4; p less than 0.05). After 9 months it did not differ from the starting point (3.4 and 4.0, respectively). In a long-term intervention study with a homogenous group of patients with familial polyposis, supplemental dietary calcium did not affect mucosal risk factors for colon cancer.

Adenomatous Polyposis Coli↗
PubMed1989

The contact site A glycoprotein of Dictyostelium discoideum carries a phospholipid anchor of a novel type.

The contact site A glycoprotein, a cell adhesion protein of aggregating Dictyostelium cells, was labeled with fatty acid, myo-inositol, phosphate and ethanolamine in vivo, indicating that the protein is anchored in the membrane by a lipid. This lipid was not susceptible to phosphatidyl inositol specific phospholipase C. When cleaved with nitrous acid or when subjected to acetolysis, the anchor released lipids which were different from those released from Trypanosoma variant cell surface glycoprotein, a protein with a known phosphatidyl inositol-glycan anchor. Resistance to weak and sensitivity to strong alkali indicated that the fatty acid in the contact site A glycolipid anchor was in an amide bond. On incubation with sphingomyelinase, a lipid with the chromatographic behavior of ceramide was released. These results suggest that the contact site A glycoprotein is anchored by a ceramide based lipid glycan.

Antigens, Surface↗
PubMed1989

[Intraoperative sonography for the detection of occult liver metastases in colorectal cancer].

In a prospective study of 85 patients with operation of colorectal cancer intraoperative ultrasonography of the liver was performed for the detection of liver metastases. The findings were compared with the results of preoperative ultrasonography and CT-scan as well as the findings of intraoperative inspection and palpation of the liver. Seventeen (24.3%) of a total of 70 metastases of this series could only be detected by intraoperative ultrasonography. This was related to 12 (14.1%) of the examined patients. Four (5.7%) of these lesions were solitary and concerned 4.7% of the cases. Due to the intraoperative sonographic findings the tactics of operation was changed in 15.3% of the patients. Intraoperative ultrasonography has a significantly higher sensitivity for the detection of liver metastases from colorectal cancer than preoperative ultrasonography and computed tomography or intraoperative inspection and palpation. Intraoperative ultrasonography of the liver should be applied in all patients without preoperative evidence of liver metastases and in patients with a planned resection of metastases.

Colorectal Neoplasms↗
PubMed1989

The "steakhouse syndrome". Primary and definitive diagnosis and therapy.

Over a period of 5 years, 28 instances of acute food impaction of the esophagus were documented in 26 patients at our institution. In all patients the impacted bolus was successfully removed without complication using a flexible endoscope. Underlying diseases were identified during primary endoscopy in 31% of the cases. Further diagnostic workup was performed in all but 5 of the patients. After adequate evaluation pathologic findings were demonstrated in 90% of the cases (38% malignant and 52% benign diseases). Long-term therapy was deemed necessary in 17 of these 21 patients. Operative intervention was indicated in 4 cases, 2 of which were for malignant tumors. Acute food impaction should always be regarded as a symptom of esophageal disorders. In patients with esophageal cancer or other mediastinal tumors bolus impaction generally indicates an advanced tumor stage.

Airway Obstruction↗
PubMed1989

The relationship of nuclear staining density and mode of stromal invasion with axillary metastases and hormone receptor status in human breast cancer.

Biopsies from 52 cases of infiltrating duct carcinoma of breast were assessed for proportions of tumor infiltrating stroma as "thin" strands and as confluent cell sheets. The proportions of cell nuclei arbitrarily designated "dark" were determined for each whole tumor and for their above-mentioned invasive compartments and were compared with the tumor's nuclear grade, mitotic index, gross size, axillary metastatic status, and hormone receptivity. Well-differentiated tumors tended to have more cells with "dark" nuclei and more of the tumor mass invading the stroma as "thin" strands than poorly differentiated ones. Tumors that had axillary metastases also tended to have high mitotic indices, low proportions of cells with "dark" nuclei (and conversely high proportions of cells with vesicular nuclei) in confluent sheets. Tumors that had positive results for one or both hormone receptors had a greater component of trabecular stromal invasion than tumors with negative results for both hormone receptors that grew as confluent cell sheets. It is suggested that tumor cell nuclear staining "density" might be a clinically useful prognostic index despite the finding that semiquantitative assessments of nuclear density can be modified by the mode of stromal invasion.

Adult↗
PubMed1989

Effect of calcium supplementation on mucosal cell proliferation in high risk patients for colon cancer.

Recent findings suggest that supplemental calcium could lower the abnormally high proliferation rate found in the colonic mucosa of subjects at high risk for colon cancer. In this double blind controlled study, this effect in volunteers previously operated upon for a colorectal adenocarcinoma was tested. Thirty subjects were randomised to receive either elemental calcium 1200 mg/day or a placebo. Mucosal proliferation was measured with tritiated thymidine labelling before and after the 30 day intervention period. Diets, faecal pH and the concentration of calcium and bile acids in the aqueous phase of feaces were also measured. Labelling index did not differ significantly in the two groups before intervention (placebo 4.0(2.4) v calcium 4.9(2.9), but the difference approached significance afterwards (4.4(2.4) v 6.5(3.4), p = 0.06). Individual changes occurring with intervention were tabulated and comparison of the means for the groups was not significant (delta = 0.3 vs delta = 1.8, p = 0.11). Calcium concentration, faecal pH and deoxycholic acid concentration increased in the calcium group (p = 0.02, 0.005 and 0.004 respectively). Calcium does not show any effect in decreasing colonic mucosal proliferation in this high risk group for colon cancer; it may increase faecal pH and the production of deoxycholic acid in the colon.

Aged↗
PubMed1988

[Effect of prostaglandin E1 on the formation of experimental arterial and venous thrombosis].

The effect of prostaglandin E1 on thrombus formation and haemostasis was investigated in a standardized experimental model in 20 rabbits. Arterial thrombus formation was reduced significantly by 70% and venous thrombosis by 68% in comparison with the controls. Collagen- and ADP-induced platelet aggregation was also inhibited significantly. Additionally, the time lag until onset of collagen-induced aggregation was significantly prolonged. Platelet count however, and plasma coagulation time showed no change. The data demonstrate a clear inhibition of arterial and venous thrombus formation, suggesting a powerful antithrombotic activity of prostaglandin E1. The effect may be explained by an influence on platelet function. The data further indicate that a full antithrombotic effect is achieved during prostaglandin E1 infusion.

Alprostadil↗
PubMed1988

Leukergy in inflammatory bowel disease.

In the phenomenon of leukergy, white blood cells agglomerate in peripheral blood slides. This agglomeration has been described in inflammatory infections of various causes. This study assesses this phenomenon in inflammatory bowel disease. A correlation was found between the severity of inflammatory bowel disease activity and the percentage of leukergy. Leukergy was found to parallel the clinical and endoscopic findings of inflammatory bowel disease. Furthermore, leukergy was found to be more accurate than white blood count and erythrocyte sedimentation rate. It is also found to accurately assess the course of the disease when clinical and other laboratory tests were masked by steroid and antibiotic administrations. Leukergy is a quick, inexpensive test that can easily be performed at the patient's bedside.

Adolescent↗
PubMed1988

Proliferative activity of rectal mucosa and soluble fecal bile acids in patients with normal colons and in patients with colonic polyps or cancer.

Rectal biopsies and fecal collections were obtained from a consecutive series of 34 outpatients prior to colonoscopy at a gastroenterology clinic. Subsequently, 14 were found to have no colonic pathology, 13 had adenomatous polyps, (3 of those had a previous history of colon cancer) and 7 were diagnosed with colon cancer. In confirmation of earlier studies the tritiated thymidine labelling index was higher in patients with tumors than in those without pathology (7.9% vs. 5.8% with P = 0.06). The patients with colonic tumors also had significantly higher levels of deoxycholic acid (P = 0.01) and lithocholic acid (P = 0.005) in the aqueous extract of their feces. This study shows that these biochemical measures may indicate colon cancer risk.

Bile Acids and Salts↗
PubMed1988

Effect of high fat consumption on cell proliferation activity of colorectal mucosa and on soluble faecal bile acids.

To assess the effect of fat consumption on the proliferation of the rectal mucosa, 30 normal volunteers (22 to 71 years) were randomly allocated to three groups: (a) basal low fat diet containing 30 g of fat per day; (b) the basal diet with doses of 30 g corn oil taken with each of the three meals: 120 g fat/day; (c) the basal diet with one dose of 90 g corn oil after the last meal: 120 g fat/day. Rectal biopsies were taken 15 cm from the anal verge after five days on the diets and mucosal cell proliferation was measured by labelling index (LI). The LI was significantly (p less than 0.01) higher in group (c) (9.2) than in group (a) (5.9), with group (b) intermediate (6.8). In multiple stepwise regression analysis, the data were best fitted with age and the variable indicating fat consumed as a bolus as predictors of LI (r2 = 0.39, p less than 0.001). In separate analyses the regression coefficient with age in the fat bolus group was 0.23, p less than 0.001. There was some tendency towards lower bile acids in the faecal water in group (a) than in groups (b) and (c) following the diets and between the bile acids and LI (for lithocholic acid r = 0.48, p = 0.01). These data show that dietary fat given as a bolus can lead to an increase in the proliferation of human colonic cells, possibly as a consequence of raised levels of cytotoxic acidic lipids in the faecal stream.

Adult↗
PubMed1988

Hidden loop jejunostomy--an experimental model.

A hidden loop jejunostomy, the placement of a proximal small bowel loop under the skin of dogs, is described. A feeding tube was inserted in the loop at a later date, which enabled feeding for at least 6 weeks. This procedure was well tolerated by the 10 dogs involved in this experimental model. It should be considered as a possible surgical procedure at initial explorative laparotomy in patients with advanced cancer originating at the gastric cardia or esophagogastric junction.

Animals↗