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Biomedical subjects

T Gilat

Publications and source records attributed to T Gilat.

At least 73 records · Page 4Linked to original sources
PubMed1993

Effect of phospholipids and their molecular species on cholesterol solubility and nucleation in human and model biles.

Much research in the pathophysiology of gall stones has been devoted to various molecular species of bile salts. Recent findings have shown the importance of phospholipids in biliary pathophysiology. In the present study the addition of increasing doses of egg lecithin to human and model biles progressively prolonged the nucleation time. Concurrently biliary cholesterol was shifted from the vesicular to the non-vesicular carrier(s) while the cholesterol/phospholipid ratio of the remaining vesicles was progressively lowered. Model bile solutions of identical lipid concentration were prepared using phosphatidylcholine, phosphatidylserine, and phosphatidylethanolamine as the only phospholipid. With phosphatidylethanolamine most of the cholesterol was shifted to the vesicular carrier while phosphatidylserine shifted most of the cholesterol to the non-vesicular carrier(s). With phosphatidylcholine the cholesterol was distributed in both carriers. Phosphatidyl choline species composed of various acyl fatty acids in the sn-1 and sn-2 positions were used as the sole phospholipid in otherwise identical model bile solutions. With palmitic acid in the sn-1 position and arachidonic acid in the sn-2 position most of the cholesterol was found in the non-vesicular carrier. When stearic acid was used in sn-2 position instead of arachidonic acid most of the cholesterol was found in the vesicular carrier. These and other variations in phospholipid molecular species shifted cholesterol among its carriers and also modified the nucleation time of model biles. Most of these effects were also found upon addition of the various phospholipid species to human biles. These findings show the importance of phospholipid species in biliary pathophysiology and may be useful when trying to manipulate cholesterol carriers and solubility in bile.

Bile↗
PubMed1993

Extracorporeal shock wave lithotripsy of gallstones: early experience in an Israeli population.

Fifty-four patients with symptomatic gallbladder stones were treated by extra-corporeal shock wave lithotripsy (ESWL) and oral bile acids on an outpatient basis. In 49 patients (90%), the stones were successfully fragmented to fragments < 5 mm on follow-up ultrasonography. Patients underwent 1-3 lithotripsy sessions with 7,500-9,750 shock waves per session. The gallbladder clearance rate of fragments was dependent mainly on the number of stones and reached 59% for patients with one or two stones, compared to 34% for patients with more than two stones after 9 months follow-up. The only side effects noted were mild abdominal pain, transient microscopic hematuria and minimal impairment in liver function tests. There were no serious complications such as cholecystitis, bile duct obstruction, or pancreatitis. These results, which are comparable with those of other groups using the same shock wave lithotriptor, indicate that this therapy may become an alternative treatment for selected patients with symptomatic gallbladder stones, especially those who are at high risk for surgical treatment.

Administration, Oral↗
PubMed1993

Anionic polypeptide fraction in bile of patients with and without gallstones.

With the demonstration of pronucleating and antinucleating proteins, the role of biliary proteins became of considerable research interest. Anionic polypeptide fraction is the third most abundant biliary protein; it is found in association with biliary lipids, has antinucleating properties for calcium and is found in gallstones. Its levels in various human biles have not been studied as of this writing. In this investigation the concentration of anionic polypeptide fraction in gallbladder bile was measured in 16 subjects without gallstones, 19 subjects with cholesterol stones and 15 subjects with pigment stones in Tel Aviv. Anionic polypeptide fraction concentrations in bile (mean +/- S.D.) were 0.76 +/- 0.09 gm/L in controls and 0.81 +/- 0.25 gm/L (which was not significant) in patients with cholesterol gallstones. They were significantly higher 1.03 +/- 0.23 (p < 0.05) in patients with pigment gallstones. The anionic polypeptide fraction/phospholipid ratio and the anionic polypeptide fraction/total lipid ratio were significantly higher in patients with pigment gallstones (p < 0.005 and 0.05, respectively). The anionic polypeptide fraction lipid ratios were insignificantly elevated in biles of patients with cholesterol stones compared with the ratios in biles of controls. Only the anionic polypeptide fraction/phospholipid ratio was significantly higher in biles of patients with pigment stones compared with those with cholesterol gallstones. The values were similar although higher in a small group of gallstone patients from Marseilles. The role of anionic polypeptide fraction in the pathogenesis of gallstones, particularly pigment gallstones, requires further study.

Adult↗
PubMed1993

Gastric polypoid lesions--an eight-year study.

We have reviewed the eight years of experience with gastric polypoid lesions of a university hospital serving the Tel Aviv area, and analyzed 188 polyps. No clinical or endoscopic findings were able to distinguish the polyp variants prior to histological examination. The most frequent type of polyp was the hyperplastic polyp (45.2%), followed by the inflammatory type (29.3%). There were six cases of adenoma and ten cases of gastric carcinoma. The polyps were distributed equally within the body (44.7%) and antrum (48.9%), while the fundus was rarely involved (6.3%). Our findings are compatible with the statement that in general there is no distinction between the histological types classified by sex, age, location, symptoms or endoscopic appearance. Nevertheless, this is the first report of a higher incidence of gastric polyps among Ashkenazi Jews than non-Ashkenazi Jews with identical sex distribution.

Adult↗
PubMed1992

Halitosis and Helicobacter pylori. A possible link?

The exact pathophysiological mechanism of halitosis is not clear, and in many patients the etiology is an enigma. We followed three couples in which one member or both had halitosis. All the subjects had evidence of Helicobacter pylori infection. All received a treatment course of colloidal bismuth subcitrate four times a day and 250 mg metronidazole three times a day. There was impressive improvement in their symptoms, the halitosis disappearing along with eradication of the organism. We call the attention of physicians to the possible connection between halitosis, H. pylori infection, and familial occurrence. Further studies to confirm this surprising association are in order.

Antacids↗
PubMed1992

Free fatty acids have nucleating effects in model biles.

Nucleating factors are thought to be responsible for the more rapid nucleation of gallbladder bile from patients with gallstones as compared to controls. Biliary proteins and, in particular, mucus and non-mucus glycoproteins are the focus of current research. Non-protein nucleating factors were not extensively investigated. In this study we studied the role of free fatty acids (FFA) as possible nucleating factors. Palmitic, oleic and linoleic acid were added to model biles in increasing concentrations from 0 to 20 mu mol/ml. The nucleation time of model biles decreased to 45%-60% of the initial following the addition of 0.5 to 1 mu mol/ml of each of the three fatty acids. Only a small further decrease in the nucleation time was noted with higher concentrations of up to 20 mu mol/ml. The pronucleating effect of FFA added to whole model bile was also examined in the isolated vesicular and non-vesicular fractions. The decrease in the nucleation time at each concentration of the three fatty acids was in the following order of magnitude: whole bile greater than vesicular phase greater than non-vesicular phase. The addition of each of the three fatty acids resulted in a partial solubilization of vesicles, with transfer of their lipid contents to the non-vesicular fraction. The effect was more marked with oleic acid and least marked with linoleic acid. The vesicular cholesterol to phospholipid ratio did not change following the addition of exogenous free fatty acids. Studies with labeled FFA showed that they migrated with the non-vesicular fraction on gel chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile↗
PubMed1992

Effect of lipid infusion on bile composition and lithogenicity in patients without cholesterol gall stones.

A prospective study was performed to investigate the effect of short term lipid infusion on bile composition and its lithogenicity in humans. Thirty five patients shown to be free of cholesterol gall stones participated in the study. Starting 48 hours before surgery they were infused randomly with a lipid emulsion of either long chain triglycerides (LCT) or a mixture of medium and long chain triglycerides (MCT/LCT) (50%/50%) for six hours each 24 hours. A group of patients infused with a solution of 5% glucose in NaCl 0.9% served as a control. Bile samples were obtained by puncture of the gall bladder during operation. Both lipids caused an increase in biliary cholesterol and phospholipids but this effect was more pronounced and significant (p < 0.001) only with the MCT/LCT emulsion. The fatty acid composition of biliary phospholipids was not affected by either lipid infusion. The cholesterol saturation index increased significantly (p < 0.005) with the MCT/LCT emulsion and there was shortening in the nucleation time but this was not significant. There was no effect on the distribution of cholesterol between micelles and vesicles. This study shows that infusion of MCT/LCT lipid emulsion can cause lithogenic changes in bile composition in humans and may thus contribute to sludge formation and cholelithiasis during long term parenteral nutrition.

Bile↗
PubMed1992

Streptococcus bovis endocarditis as a presenting manifestation of idiopathic ulcerative colitis.

Streptococcus bovis bacteraemia and endocarditis have been associated with several gastrointestinal diseases, mainly malignant or potentially malignant tumours, and less commonly non-malignant gastrointestinal disorders. We describe a 73 year old man in whom Streptococcus bovis endocarditis developed, and was the presenting manifestation of undiagnosed quiescent ulcerative colitis. Such an association has not been described previously.

Aged↗
PubMed1992

Prostaglandin E2 in duodenal ulcer complications.

Prostaglandins are presumed to have cytoprotective properties and may play a role in the pathogenesis of duodenal ulcer and its complications. To evaluate this hypothesis, 35 patients with either duodenal ulcer bleeding (18 patients) or gastric outlet obstruction (17 patients) were investigated. Biopsies were taken from gastroduodenal tissues and secretions for prostaglandin E2 (PGE2) levels. These levels were compared to those taken from the same areas during a later endoscopy. A correlation was found between the severity of the clinical endoscopic findings and PGE2 levels. Increased levels of PGE2 were found in the quiescent phase and decreased levels found during the deteriorated phase. These differences of PGE2 levels were found to be of significant value (P less than 0.002). Furthermore, the patients in which the PGE2 levels were decreased at second endoscopy needed surgery. PGE2 may, thus, be a factor in duodenal ulcer pathogenesis and its complications, and be used as a prognostic marker and guide.

Acute Disease↗
PubMed1991

The induction of lamellar stacking by cholesterol in lecithin-bile salt model systems and human bile studied by synchrotron X-radiation.

Small angle X-ray scattering (SAXS) with synchroton radiation was used to investigate interactions among lipid particles in lecithin-bile salt model systems and in native gallbladder biles. In model systems in the absence of cholesterol, isotropic, continuous spectra were found, indicating the absence of periodic structures. In the presence of excess cholesterol, interaction in the form of lamellar stacking was detected by the appearance of discrete diffraction peaks. In the supersaturated cholesterol region of the commonly accepted phase diagram [1], where cholesterol crystals were expected, we found lamellar stacking. The high proportion of cholesterol to bile salts seems to be the common denominator of these models. The lamellar stacking was also found in native unprocessed bile. This effect of cholesterol on lipid structure has not been previously described. Lamellar stacking may contribute to cholesterol solubilization. Its influence on the kinetics of cholesterol crystallization is presently unknown.

Bile↗
PubMed1991

D-xylose absorption test. Urine or blood?

The D-xylose absorption test has been used during the last four decades for evaluation of malabsorption in the small intestine. However, some disagreement still exists about the recommended method of performing this test: the 1-hr blood test, the 5-hr urine test, or both. We evaluated the test by performing 125 combined blood and urine tests in 111 patients. Normal xylose absorption was recorded in both blood and urine in 71 tests (group A, 56.8%). Abnormal test results in both blood and urine were recorded in 29 patients (group B, 23.2%). Only one patient had a pathological blood value and normal xylose excretion in the urine. Twenty-four patients (group D, 19.2%) had normal 1-hr blood xylose (greater than 25 mg/100 ml) with abnormal 5-hr urine xylose (less than 4.5 g/5 hr). Fat and/or bile salt malabsorption were documented in 21 patients (87.5%) of this group using stool fat analysis and the [14C]cholylglycine breath test. These data suggest that in adults the 5-hr urine collection more accurately reflects intestinal absorption in comparison with the 1-hr blood value.

Adolescent↗
PubMed1991

A controlled trial of beclomethasone versus betamethasone enemas in distal ulcerative colitis.

Steroid enemas are widely used in distal inflammatory bowel disease (IBD). They are partly absorbed and suppress adrenocortical function. Beclomethasone dipropionate (BD) is a topically active steroid that undergoes rapid first-pass inactivation in the liver and is practically devoid of systemic side effects. We treated 32 consecutive patients with active distal ulcerative colitis (40 attacks) with 0.5 mg BD and/or 5 mg betamethasone phosphate (BP) enemas for 28 days. Clinical, laboratory, sigmoidoscopic, and histologic data were recorded before, during, and after the trial. The clinical efficacy of both treatments was similar. Betamethasone was slightly more effective in relation to the histologic improvement and disappearance of blood from the stools. Clinical signs of steroid overdosage were noted in patients on BP but not in patients on BD. Mean fasting plasma cortisol at the end of the trial was 2.9 micrograms/dl in the BP group and 15.3 micrograms/dl in the BD group. The adrenocorticotropin test was markedly suppressed in the BP group but not in the BD group. The absence of systemic steroid side effects makes BD enemas a useful addition in the therapy of IBD. Its oral administration should also be considered.

Adult↗
PubMed1990

Phospholipid lamellae are cholesterol carriers in human bile.

Cholesterol solubility and precipitation in bile are major factors in the pathogenesis of cholesterol gallstones. At present, mixed micelles and phospholipid vesicles are considered to be the only cholesterol carriers in bile. In this study we present evidence showing that phospholipid lamellae are major cholesterol carriers in human bile. Lamellae are a known aggregational form in pure phospholipid model systems. In the present study, lamellae were demonstrated by electron microscopy after negative staining and by small-angle X-ray diffraction in all human gallbladder bile samples examined. During diffraction experiments, cholesterol was found to crystallize from these lamellae. Cholesterol carriers in bile were separated by high-resolution chromatography and by prolonged ultracentrifugation. Lamellae were shown to solubilize most of the biliary cholesterol; vesicles solubilized a lesser amount; while micelles solubilized only a minor portion. Our data suggest that phospholipid aggregates are the main cholesterol carriers in bile. Bile salts may control the equilibrium between the various aggregational forms of cholesterol-carrying phospholipids.

Bile↗