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Biomedical subjects

Z Halpern

Publications and source records attributed to Z Halpern.

At least 109 records · Page 6Linked to original sources
PubMed1986

Rapid vesicle formation and aggregation in abnormal human biles. A time-lapse video-enhanced contrast microscopy study.

Rapid nucleation of cholesterol crystals has previously been shown to provide a sharp discrimination between abnormal (cholesterol gallstone-associated) and normal human gallbladder bile. In the present study, we sought to further clarify the crystal nucleation process by time-lapse microscopy using a novel high-resolution video-enhanced microscopy technique. Using a previously described method for removal of particles from abnormal biles, we found a strikingly rapid rate of de novo formation of unilamellar vesicles, soon followed by massive vesicular aggregation, culminating in crystal formation. In normal biles, by contrast, this rapid aggregation process was not observed and the isolated unilamellar vesicles showed prolonged stability. Morphometric analysis of interval particle counts showed statistically significant differences. The process of cholesterol monohydrate crystal nucleation in supersaturated human bile is characterized by a sequential combination of vesicle formation, vesicle aggregation, and subsequent crystal formation. The primary distinction between abnormal and normal biles resides only in the consistent rapidity of onset and completion of these events in the abnormal biles.

Bile↗
PubMed1986

Vesicle aggregation in model systems of supersaturated bile: relation to crystal nucleation and lipid composition of the vesicular phase.

The presence of small vesicles composed of phospholipid and cholesterol has recently been demonstrated in super-saturated model and in dilute native human biles by several groups using differing methods. Among compositional factors shown to favor spontaneous vesicle formation and prolong the cholesterol monohydrate nucleation time in model bile systems are dilution, a raised cholesterol saturation index (CSI), and a low bile salt/phospholipid ratio. Time-lapse video-enhanced microscopy of a series of model bile systems representing systematically designed variations in the above factors revealed strong evidence for an essential linkage between antecedent vesicle aggregation and subsequent crystal nucleation. Stability of vesicles was inversely related to their degree of cholesterol saturation, i.e., the greater the degree of vesicular cholesterol saturation, the less their stability (metastability). Instability of vesicles was reflected by their early aggregation followed by rapid cholesterol crystal nucleation. The lowest degree of vesicular cholesterol saturation was found in dilute systems which also exhibited the greatest metastability despite a high degree of cholesterol solubility (raised CSI). Conversely, the more concentrated and least metastable systems exhibited both rapid vesicle aggregation and rapid onset of crystal nucleation. These systems, while influenced by the other compositional factors, were found to have a high degree of vesicular cholesterol saturation, i.e., cholesterol/phospholipid molar ratio = 2.0. An additional finding was the extreme variability in the proportionate distribution of total solution cholesterol distributed to the vesicular phase, i.e., from zero to as high as 37%. Higher solute concentration, raised bile salt/lecithin ratio, and raised CSI were interactive and almost equally capable of increasing the proportionate amount of cholesterol in the vesicular phase. In conclusion, lipid compositional differences in model bile systems drastically affect the cholesterol saturation of spontaneously formed phospholipid-cholesterol vesicles. This effect, in turn, exerts a potent influence upon the metastability of vesicles, subsequently affecting the cholesterol crystal nucleation time.

Bile↗
PubMed1985

[Lyme disease].

Explore the source record for details and available documents.

Humans↗
PubMed1985

Pseudoaneurysm of the dorsalis pedis artery.

Two cases of post-traumatic pseudoaneurysm of the dorsalis pedis artery are presented. Both were managed by resection and vascular reconstruction with a successful result. It is suggested that this, rather than resection and ligation, is the preferred treatment in these cases.

Adult↗
PubMed1985

Gallstones and diet in Tel Aviv and Gaza.

To study the possible association between diet and gallstones we investigated these two variables in two populations in Tel Aviv and Gaza with presumed differences in both. Gallstones were more frequent in Jews in Tel Aviv than in Arabs in Gaza, 12.1% versus 3.8% (p less than 0.001). This difference was fully accounted for by the 60+ age groups in both populations. There were no significant differences in the frequency of gallstones among the 20-39 and 40-59 age groups. Numerous and marked differences in diet composition were found between both populations. Energy, carbohydrate and fiber intake was higher in Gaza. The consumption of unsaturated fats was greater in Gazans and their P/S ratio was higher, 0.92 versus 0.70 in Tel Aviv. Beef and fish were usually eaten in Gaza while poultry was more frequently consumed in Tel Aviv. There were also differences in vitamin and mineral consumption. It cannot be determined which, if any, of these dietary differences is related to the lower frequency of gallstones in the older population of Gaza. Alternatively it could be the diet eaten in Gaza many decades ago, presumably poorer in protein and fat, which is responsible for these differences.

Adult↗
PubMed1985

Effect of (+)-cyanidanol-3 on chronic active hepatitis: a double blind controlled trial.

Forty patients with biopsy proven chronic active hepatitis were studied, 22 received (+)-cyanidanol-3 in a dose of 3 g daily and 18 placebo. Side effects related to cyanidanol were fever (four patients), haemolysis (one patient) and urticaria (one patient). All side effects subsided on discontinuation of the medication. Cyanidanol had an effect no better than placebo on symptoms, laboratory tests, and histological findings on liver biopsy.

Benzopyrans↗
PubMed1985

Severe hemochromatosis: the predominant clinical manifestation of congenital dyserythropoietic anemia type 2.

A patient with multiorgan involvement of non-iatrogenic hemochromatosis secondary to congenital dyserythropoietic anemia (CDA) type 2 is described. The clinical manifestations of hemochromatosis preceded the diagnosis of CDA. CDA should be included among the hematological disorders associated with iron overload. Iron therapy and blood transfusions should be avoided if possible in patients with CDA, and all such patients should be carefully screened for the known complications of iron overload.

Adult↗
PubMed1985

Sulfasalazine pneumonitis.

A patient with ulcerative colitis developed skin allergy to sulfasalazine, manifested by rash urticaria and generalized angioedema. The patient underwent desensitization with the drug. After desensitization, the drug was reinstituted without any adverse skin reaction. However, 2 months later the patient developed a severe pneumonitis that resolved completely on discontinuation of sulfasalazine and administration of steroids. The relationship between the various adverse reactions to the drug is discussed and the entity "sulfasalazine pneumonitis" is reviewed.

Angioedema↗
PubMed1985

The everted rectal stump technique for the application of the distal pursestring suture in the construction of stapled anastomoses.

The everted rectal stump technique for the application of the distal pursestring suture was used successfully in three patients to perform a low stapled reconstructive anastomosis in the treatment of carcinoma of the rectum. Two of the patients were Dukes' Stage B and one patient was classified as Dukes' Stage C. The postoperative course was uneventful. There were no complications and all three were free of tenesmus and cutaneous irritation and were continent of flatus and feces, with one to three movements per day.

Humans↗
PubMed1985

Factors affecting cholesterol monohydrate crystal nucleation time in model systems of supersaturated bile.

We explored the influence of several compositional factors considered capable of influencing the nucleation time of model biles supersaturated in cholesterol. In addition to the classical techniques, e.g., electron microscopy and quasielastic light scattering, employed for size measurement and structural assessment, we employed a novel technique, i.e., video-enhanced microscopy, for particle evaluation in these polydisperse systems which often may simultaneously contain isolated small vesicles, their complex aggregates, and small cholesterol monohydrate crystals. The factors we studied included dilution, degree of cholesterol supersaturation, bile salt/lecithin molar ratio, and Ca2+ concentration. Dilution markedly raised the degree of cholesterol saturation, prolonged nucleation time for cholesterol monohydrate crystals, and favored formation of metastable small unilamellar vesicles. Increasing the degree of cholesterol supersaturation as an independent variable in more concentrated systems both shortened the nucleation time and favored spontaneous formation of a relatively small number of isolated vesicles. A decrease in bile salt/lecithin molar ratio within the physiologically relevant range was accompanied by a prolonged nucleation time and favored spontaneous vesicle formation. Large numbers of small unilamellar vesicles were observed even in concentrated model bile solutions (total lipids: 20 g/dl) when the bile salt/lecithin molar ratio was 1.9 or less. At physiological concentrations, Ca2+ promoted nucleation of cholesterol monohydrate crystals only in vesicle-containing solutions. Taken together, the following conclusions can be drawn. First, spontaneous vesicle formation in dilute systems prolongs solid cholesterol crystal nucleation. It can thus provide a supplementary non-micellar mode of cholesterol transport in micellar systems of supersaturated human bile. Second, dilution, degree of cholesterol supersaturation, and a decrease in bile salt/lecithin ratio prolong cholesterol crystal nucleation time and favor spontaneous vesicle formation. With increasing calcium concentrations, opposite effects are observed. Third, the presence of vesicles may help to account for the frequently observed and otherwise unexplained remarkable degree of metastable supersaturation and prolonged metastability (delayed nucleation time) for cholesterol in human bile.

Bile↗
PubMed1984

Coumadin-induced skin necrosis.

Two women developed coumadin-induced skin necrosis. A 16-year-old woman sustained necrosis on the leg after a single dose of the drug, and a 59-year-old woman developed gangrene of most of her left breast.

Adolescent↗
PubMed1984

Failure of balloon membranotomy of the inferior vena cava.

A young woman with membranous obstruction and coarctation of the inferior vena cava is described. A balloon membranotomy was performed with a transient improvement. Three months later massive thrombosis of the inferior vena cava developed. It appears that balloon membranotomy alone is contraindicated in the presence of both stenosis and membranous obstruction of the inferior vena cava.

Adult↗
PubMed1984

The significance of the diameter of the common bile duct in cholecystectomized patients.

In the cholecystectomized patients there is no correlation between the diameter of the common bile duct and the pressure in the biliary system or in the sphincter of Oddi. It is most probably due to unresolved dilatation of the common bile duct. ERCP manometry is probably a more accurate technique for establishing the diagnosis of papillary stenosis in patients who had their gallbladder removed.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1983

Cellular sensitivity to collagen in thromboangiitis obliterans.

We studied 39 patients with thromboangiitis obliterans to determine their cellular and humoral immune responses to native human collagen Type I and Type III, which are constituents of blood vessels. Cell-mediated sensitivity to these collagens was measured by an antigen-sensitive thymidine-incorporation assay. The mean stimulation index--the ratio of thymidine incorporation in the presence of antigen to that in its absence--with both Type I and Type III collagens used as antigens was significantly higher in patients with thromboangiitis obliterans than in patients with arteriosclerosis obliterans or in healthy male controls. Lymphocytes from 77 per cent of the patients with thromboangiitis obliterans exhibited cellular sensitivity to human Type I or Type III collagens (or both). Furthermore, in 17 of 39 serum samples from the patients with thromboangiitis obliterans a low but significant level of anticollagen antibody activity was detected, whereas there was no antibody activity in serum samples from controls. These results suggest that there is a distinct etiologic factor in this disease and also raise the possibility of differentiating between thromboangiitis obliterans and arteriosclerosis obliterans by immunologic means.

Adult↗
PubMed1983

Nitrate therapy in a patient with papillary dysfunction.

A 64-yr-old woman with ERCP manometry proven papillary dysfunction is described. This patient responded to nitrate therapy with disappearance of the pain and decrease in both basal and phasic sphincter activity. It is suggested that nitrate administration should be used to distinguish between patients with functional and organic pathology of the sphincter of Oddi. Nitrate therapy should be tried in patients with papillary dysfunction and only if this fails, should endoscopic sphincterotomy be considered.

Ampulla of Vater↗