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Biomedical subjects

Y Krausz

Publications and source records attributed to Y Krausz.

At least 55 records · Page 3Linked to original sources
PubMed1989

Platelet survival in patients with beta-thalassemia.

Thromboembolic events associated with significant morbidity and mortality have been observed in patients with beta-thalassemia major (TM). These include arterial as well as venous thrombosis and the development of early arteriosclerosis. To elucidate the possibility that TM patients may develop a hypercoagulable state we carried out a study of platelet kinetics on ten patients with TM and four patients with thalassemia intermedia (TI). Autologous platelets were labeled with indium-111-oxine, and the platelet lifespan (PLS) was determined. A significant shortening of PLS was observed in 13 out of 14 patients examined. The mean PLS (+/- 1 SD) in ten patients (8 TM, 2 TI) who underwent splenectomy was 107 +/- 36 hr (control splenectomized 248 + 51 hr) (P less than .001) and in four nonsplenectomized patients (2 TM, 2 TI) was 102 +/- 64 hr (control 224 + 23 hr) (P less than .01). The short PLS in addition to reported findings of increased circulating platelet aggregates and the decreased response of TM platelets to aggregating agents suggests in vivo platelet activation in thalassemic patients.

Adolescent↗
PubMed1989

Brain SPECT imaging with Tc-99m HM-PAO in Creutzfeld-Jakob disease.

A Tc-99m HM-PAO brain SPECT study of a patient with biopsy-proven Creutzfeld-Jakob disease demonstrated perfusion defects in the left frontal and right temporoparietal areas. A brain CT was normal. The clinical potential of this imaging modality in the evaluation of dementia is discussed.

Aged↗
PubMed1989

Differential lung function in an infant with the Swyer-James syndrome.

A previously healthy two year old boy had an adenoviral infection at the age of 13 months and developed hyperlucency of the left lung, chronic respiratory distress, and failure to thrive. Bronchodilators and steroid treatment had no effect. Radionuclide lung scans using an intravenous bolus of xenon-133 both before and after treatment showed substantially reduced function on the hyperlucent side and modestly reduced function on the other side. Fibreoptic bronchoscopy showed no structural abnormalities. Partial forced expiratory flow volume (PEFV) curves, generated from end inspiration by rapid compression of the chest wall with an inflatable jacket, were obtained from the total respiratory system and from each lung separately by inflating a Fogarty catheter in the contralateral mainstem bronchus. Expiratory flow rates and volumes during both tidal breathing and PEFV manoeuvres were considerably decreased in the hyperlucent lung. PEFV curves from the "healthy" right lung and from the total respiratory system were similar in shape and showed a moderately obstructive pattern. The right lung ventilated about four times as much as the left when measured by bronchospirometry and about three times as much when measured by the radionuclide technique. The lung scans appeared to reflect adequately the functional abnormality in this infant with the Swyer-James syndrome.

Child, Preschool↗
PubMed1989

Successful splenectomy in May-Hegglin anomaly: report of a case with platelet kinetic studies.

Bleeding diathesis is not necessarily one of the conspicuous and serious characteristics of the macrothrombocytopenic syndromes, which include the May-Hegglin anomaly. Nevertheless, occasionally prolonged bleeding time may endanger organs or even life. We report a case of a young girl with severe thrombocytopenia due to May-Hegglin anomaly, who was facing blindness because of intraocular haemorrhages. Being unable to intervene in the pathogenesis of the disease, we performed splenectomy after proving splenic sequestration of platelets. This procedure allowed the performance of a successful bilateral vitrectomy.

Blood Platelets↗
PubMed1987

Calcium-binding proteins and insulin release. Differential effects of phenothiazines on first- and second-phase secretion and on islet cAMP response to glucose.

Calcium and cAMP are interdependent regulators of glucose-induced insulin release. In the present study we investigated the importance of cAMP and calcium-binding proteins for biphasic insulin secretion by assessing the effects of two phenothiazines known to block such proteins, trifluoroperazine (TFP) and promethazine (PMZ). In isolated rat islets, during 60-min incubations with 16.7 mmol/l glucose both agents inhibited the insulin response with ID50 values of 15 mumol/l for TFP and 5 mumol/l for PMZ. Both agents decreased the maximal insulin response without gross changes in the islet sensitivity to glucose. TFP (15 mumol/l), whereas inducing 50% inhibition of second-phase insulin release, totally suppressed the cAMP response to glucose and the accompanying first-phase insulin secretion (5-min incubations); these effects of TFP could be partially reversed by isobutyl methylxanthine (IBMX). In contrast, 5 mumol/l PMZ, which produced 60% inhibition of second-phase insulin release, had no effect on first-phase insulin and cAMP responses to glucose. Furthermore, IBMX did not modify the inhibitory effect of PMZ on second-phase insulin secretion. The following is concluded: 1. TFP acts preferentially on first-phase insulin release and inhibits cAMP formation; this suggests that calmodulin plays a major role in mediating the initial glucose effect on secretion via stimulation of cAMP. 2. The islet probably contains calcium-sensitive proteins other than calmodulin, since the low concentrations of PMZ shown to inhibit second-phase insulin release lack effects on calmodulin. Synexin could be such a protein.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-3-isobutylxanthine↗
PubMed1985

Nuclear magnetic resonance imaging of liver hemangiomas.

Nine patients with cavernous hemangioma of the liver were examined by nuclear magnetic resonance imaging (MRI) with a 0.5 T superconductive magnet. Spin-echo technique was used with varying time to echo (TE) and repetition times (TR). Results were compared with 99mTc red blood cell (RBC) scintigraphy, computed tomography (CT), echography, and arteriography. Four illustrated cases are reported. It was possible to establish a pattern for MRI characteristics of cavernous hemangiomas; rounded or smooth lobulated shape, marked increase in T1 and T2 values as compared with normal liver values. It is concluded that, although more experience is necessary to compare the specificity with that of ultrasound and CT, MRI proved to be very sensitive for the diagnosis of liver hemangioma, especially in the case of small ones which may be missed by 99mTc-labeled RBC scintigraphy.

Adolescent↗
PubMed1984

Mechanisms of synergism between glucose and cAMP on stimulation of insulin release.

The mechanism of synergism between glucose and adenosine 3',5'-cyclic monophosphate (cAMP) on insulin release has been studied. Synergism may result from 1) inhibition of Na+-Ca2+ exchange by glucose and 2) a cAMP-induced sensitization of the release machinery to Ca2+. To distinguish between these two possibilities, isolated rat pancreatic islets were perifused with agents that raise intracellular levels of cAMP [3-isobutyl-1-methylxanthine (IBMX) and forskolin] and others that increase intracellular concentrations of Ca2+ either by blocking Na2+-Ca2+ exchange (ouabain and choline-Ringer solution) or by causing increased Ca2+ influx (KCl, carbachol, and 10 mM Ca2+). The results indicate that both the combination of cAMP and increased Ca2+ influx or blocked Na2-Ca2+ exchange and increased Ca2+ influx potentiated insulin release. When the relative potentiating abilities of cAMP and blocked Na2+-Ca2+ exchange were compared by determining the individual effects of IBMX and 1 mM ouabain (a concentration that causes similar inhibition of 45C2+ efflux as 16.7 mM glucose) in the presence of carbachol, cAMP was only 1.4 times more potent as a potentiating agent than blocked Na+-Ca2+ exchange. The greatest potentiation of insulin release was observed when Na+-Ca2+ exchange was blocked in the presence of increased levels of intracellular cAMP.

1-Methyl-3-isobutylxanthine↗
PubMed1981

Origin and pattern of glucocorticoid-induced hyperlipidemia in rats. Dose-dependent bimodal changes in serum lipids and lipoproteins in relation to hepatic lipogenesis and tissue lipoprotein lipase activity.

Rats maintained for five days on a low dose of triamcinolone (0.5 mg/kg) showed a 2-fold increase in serum triacylglycerol concentration, paralleled by a rise in all very low density lipoprotein (VLDL) components but no significant change in serum cholesterol or high density lipoproteins (HDL). In contrast, a high dose of triamcinolone (12.5 mg/kg) produced a fall in triacylglycerol and VLDL to the range of control levels coincident with doubling in serum cholesterol and HDL. The rise in VLDL was attributed in a large part to enhanced hepatic fatty acid synthesis as evident from the marked rises in activity of rate-limiting enzymes of lipogenesis and in 3H incorporation into liver and serum fatty acids from in vivo administered 3H2O. The induction of fatty acid synthesis was linked to pronounced hyperinsulinemia, elicited by the triamcinolone treatment, to which the liver remained selectively responsive, contrary to the general insulin antagonism in peripheral tissues. Triamcinolone treatment also resulted in small rises in serum glucagon but these changes did not appear to be of importance for the observed bimodal serum lipoprotein perturbations. Dexamethasone, prednisolone and cortisol, administered in doses equipotent to 0.5 mg/kg triamcinolone, produced similar changes in the levels of serum triacylglycerol and insulin and activities of hepatic enzymes of lipogenesis.

Acetyl-CoA Carboxylase↗
PubMed1980

Possible role for calmodulin in insulin release. Studies with trifluoperazine in rat pancreatic islets.

The role of calmodulin in insulin secretion from rat pancreatic islets has been examined by the use of trifluoperazine, an inhibitor of calmodulin-Ca++-directed functions. It was found that 30 microM trifluoperazine caused 50% inhibition, and 100 microM, up to 73% inhibition of 16.7 mM glucose-stimulated insulin release. 100 microM trifluoperazine caused a similar inhibition of 10 mM glyceraldehyde-stimulated release. Therefore, the site of action of trifluoperazine in glucose stimulus-secretion coupling appears to be after the trioses. As trifluoperazine had no effect upon insulin release stimulated by 1 mM 3-isobutyl-1-methylxanthine, the inhibitory effect of trifluoperazine appears to be rather specific. Further, the process of exocytosis per se is not affected. It was also found that although trifluoperazine inhibited the effect of glucose to stimulate insulin release, it did not affect the synergism between glucose and 3-isobutyl-1-methylxanthine to potentiate insulin release. It may be concluded that trifluoperazine selectively inhibits one part of the mechanism by which glucose stimulates insulin release. Calmodulin plays a role in the stimulation of insulin release by glucose at a site between metabolism of trioses and elevation of cytosol Ca++, but is not involved in the final process of exocytosis.

1-Methyl-3-isobutylxanthine↗
PubMed1980

Antipyrine clearance and its correlation to routine liver function tests in patients with liver disease.

Antipyrine clearance was determined in five healthy volunteers, 10 patients with viral hepatitis and 15 patients with cirrhosis of the liver. The antipyrine clearance in controls was 30.1 +/- 2.5 ml/kg/h (S.E.M.), in patients with viral hepatitis 30.3 +/- 3.9 ml/kg/h and in liver cirrhosis 20.4 +/- 2.7 ml/kg/h. In the patients with liver disease no correlation could be demonstrated between the routine liver function tests and antipyrine clearance. The results are compared to similar studies reported previously. Antipyrine pharmacokinetics do not appear to be a clinically useful index for the hepatic drug metabolizing capacity in the individual patient with liver disease.

Adult↗
PubMed1978

Idiopathic pericarditis and pregnancy.

The association of idiopathic pericarditis and pregnancy is described in 3 patients. The disease preceded the onset of pregnancy in 2 patients and appeared during the sixth month in the third. All pregnancies reached term and the deliveries were uneventful. One patient had mild heart failure before the pregnancy. This deteriorated slightly during its course. The remaining 2 patients had no signs of heart failure and none of the 3 had arrhythmias or embolic phenomena. Two patients were treated with aspirin and prednisone and one was treated for heart failure only. All patientts are still symptomatic and require treatment 9 months, 1 year and 21 years after the pregnancy. Two of the patients underwent partial pericardiectomy.

Adult↗
PubMed1977

Macroglobulinemia of Waldenström associated with severe osteolytic lesions.

Osteolytic lesions are not known to be associated with chronic lymphocytic leukemia and are rare in macroglobulinemia of Waldenström. In the present paper we report a patient suffering from macroglobulinemia associated with chronic lymphocytic leukemia in whom osteolytic lesions, resembling those of multiple myeloma were found. Treatment with chlorambucil resulted in normalization of the peripheral blood smear, but the malignant infiltration of the bone marrow continued and manifested itself by appearance of new osteolytic lesions, though some of the old lesions underwent recalcification after treatment.

Aged↗
PubMed1977

A comparative study of hepatitis B and non-B in hospitalized adults in an endemic area.

The epidemiologic, clinical and laboratory features of 40 adults with acute viral hepatitis type B were compared with those of 40 adults with hepatitis non-B. Overall, the clinical presentations were remarkably similar and the etiology could not be determined in individual cases. An exception to this was that all post-transfusion cases in this series were affected by hepatitis B. Men predominated in both the hepatitis B and non-B groups. There was a tendency to seasonal clustering in summer/autumn in both groups. Hepatitis B patients were significantly older and 59% of them had a history of possible parenteral exposure during the six months preceding admission. On the other hand 76% of patients with hepatitis non-B had no apparent parenteral exposure. Dental treatment, injections and contact with jaundiced patients were recorded in both groups and were therefore of no value in determining the exact etiology in individual cases. Fever was more common in hepatitis non-B, while the onset of the disease was insidious and afebrile in 80% of patients with hepatitis B. As a group, patients with hepatitis B had more extensive liver injury and a more prolonged clinical course, and the only fatality was in this group. Cholestatic features were rare and extrahepatic immune complex disease was extremely uncommon in both hepatitis B and non-B.

Adult↗
PubMed1977

Thrombosis on Björk-Shiley aortic valve prosthesis. A case report and review of the literature.

A patient who developed thrombosis on a Björk-Shiley aortic valve prosthesis is reported. The patient presented with severe angina pectoris and the main physical findings were absence of the closing click of the prosthetic valve and the presence of systolic and diastolic aortic murmurs. Echocardiography showed early closure of the mitral valve and depressed left ventricular function. An emergency operation was performed and the clot was removed. The patient's recovery was uneventful and he is well one year after surgery. Awareness of the possibility of valve thrombosis is necessary in view of the need for emergency surgical treatment. The literature on the subject is reviewed.

Adult↗