Biomedical subjects
Publications and source records attributed to Y Schwartz.
Multiple ovarian follicles were successfully induced in a patient undergoing superovulation for a gamete intrafallopian transfer (GIFT) procedure despite the presence of an undiagnosed ectopic pregnancy. Midluteal gonadotropin releasing hormone agonist (GnRH-a) treatment should be coupled with mechanical contraception in the previous cycle in patients with patent tubes.
Six patients are described with a history of cold-related urticaria in whom standard tests (water-immersion and ice-cube) did not induce symptoms. Only total-body cold exposure induced generalized urticaria. Systemic cold urticaria should, therefore, be included in the differential diagnosis of cold-dependent allergic disorders.
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GH produces an acute but transient insulin-like response in adipocytes that have been deprived of GH for at least 3 h. The insulin-like response is followed by a period of refractoriness during which a second insulin-like response to GH cannot be elicited. These studies were undertaken to evaluate the role of calcium in the insulin-like response and refractoriness. Methionyl human GH (hGH) (100 ng/ml) increased the incorporation of D-[3-3H] glucose into lipid by 50-100% in fat cells that preincubated for 3 h without hormone and usually by less than 10% in fat cells that were made refractory by exposure to 100 ng/ml of hGH in the first hour of incubation. Insulin (100 microU/ml) increased lipogenesis by 3-5-fold whether fat cells were sensitive or refractory to GH. To determine whether calcium plays a role in either the insulin-like response to GH or the refractory phenomenon, we examined the effects of trifluoroperazine (20 or 50 microM) and calmidazolium (1.0 microM) which block calmodulin, as well as verapamil (30 microM), which blocks calcium channels. These agents did not interfere with stimulation of incorporation of D-[3-3H]glucose into lipid by GH (100 ng/ml) or insulin (100 microU/ml) but restored sensitivity to the insulin-like effects of GH in otherwise refractory cells. When freshly isolated, and hence refractory, cells were incubated for 1 h in calcium-free medium that contained 0.5 mM EGTA, GH stimulated lipogenesis by 30% (P less than 0.001) even though the response to insulin was markedly decreased in the absence of calcium. Conversely, when added to sensitive cells in the presence of normal extracellular Ca2+ concentrations during the 4th h of incubation, the calcium ionophore, A23187 (1.0 microM) produced an apparent refractoriness to the insulin-like effect of GH but had no effect on the response to insulin. The data indicate that maintenance of refractoriness to the insulin-like action of GH depends upon a calcium-calmodulin-sensitive process and suggest that, in producing refractoriness, GH may increase availability of intracellular calcium perhaps by increasing the rate of calcium entry into adipocytes. Since changes in responsiveness to GH were not paralleled by changes in responsiveness to insulin, it is suggested that the calcium dependent process responsible for refractoriness must lie at an early step in the signaling pathway.
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This study was undertaken to investigate the effect of ketotifen on the immune system of asthmatic children receiving prophylactic treatment with ketotifen. E. rosettes, mitogenic response to phytohemagglutinin (PHA) and concanavalin A (Con A) as well as Con A induced suppression were measured in 15 asthmatic patients before and 1-3 months after treatment with ketotifen (1 mg x 2/day), and in 20 normal healthy controls. No significant difference in immunological parameters studied were found between the pre and post treatment periods in the asthmatic patients, neither was any difference demonstrated between the asthmatic and control group studied.
Measurements of cellular immunity including the percentage of T-cell mitogenic response of lymphocytes to phytohemagglutinin (PHA) and concanavalin A (Con A), as well as Con A-induced suppressor function, were determined in 20 asthmatic children (mean age 12.4 +/- 0.6 years) before and after 6 months of theophylline therapy. Only 9 of the 20 children patients that commenced the study completed the entire 6 months of therapy. A group of 37 healthy children (mean age 12.6 +/- 0.3 years) served as control. During the 6-month period of therapy, theophylline levels were maintained between 10 and 20 micrograms%. No significant difference in any of the parameters examined were found between the initial 20 asthmatic patients and the control group. Furthermore, in the 9 patients that were evaluated before and after 6 months of theophylline therapy no significant change in lymphocyte function including suppressor function was detected. We conclude that the beneficial effect of long-term theophylline therapy in asthmatic children is probably not related to an immuno-modulatory effect.
Erythrocyte glutathione peroxidase (GPX) levels were determined in 56 asthmatic children. Lowest levels were found during acute asthmatic attack (13.53 +/- 2.94 IU) which were significantly less than controls (20.4 +/- 5.44 IU) (P less than .001). Post-attack levels 1 week later rose significantly (16.77 +/- 2.63 IU), but were still less than normal values (P = .001). GPX levels (16.96 +/- 3.28 IU) were less than controls (P less than .03) even in patients with mild symptomatology. Asymptomatic patients receiving theophylline had normal levels. Low GPX activity in asthmatic patients may play a role in the pathogenesis of the disease.
The sensitivity to lipolytic agents is altered in diabetic vs. control animals. Because of its role as a diabetogenic hormone and its ability to elicit lipolysis, GH was studied in isolated fat cells (IFC) from control and streptozotocin-diabetic (STZ-DM) rats. IFCs from the epididymal fat of 150 to 200-g normal and STZ-DM Holtzman rats were prepared by collagenase digestion. Lipolysis was measured by glycerol release after either incubation or perifusion with the following concentrations: epinephrine (EPI), 0.01-0.1 microM; theophylline, 0.01-1.0 mg/ml; adenosine deaminase (ADA), and bovine GH (bGH), 0.01-1.0 microgram/ml. Rats, rendered diabetic by STZ (65 mg/kg), were used on day 3. In a dose-response study comparing glycerol release from control and STZ-DM IFC, IFC were preincubated with 1.0 microgram/ml bGH and then incubated with varying concentrations of EPI or bGH. In STZ-DM, we noted increased lipolytic sensitivity to low concentrations of EPI or bGH. Furthermore, in perifusion, STZ-DM IFC did not require obligatory preincubation with bGH for optimal glycerol release. The addition of ADA increased glycerol release from incubated IFC (STZ-DM and controls). In both systems an enhanced lipolytic response to theophylline was seen in the presence of bGH in control and STZ-DM. It was thus concluded that IFC from normal animals do not respond to GH without preincubation. IFC from STZ-DM rats show a lipolytic response to GH without preincubation. Preincubation with GH increases the lipolytic response of IFC from STZ-DM to all lipolytic agents compared to control responses. In addition, ADA greatly enhanced lipolysis in IFC from STZ-DM compared to that in controls. Together these data demonstrate enhanced sensitivity to both lipolytic stimuli and adenosine suppression of lipolysis in IFC from STZ-DM.
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Thiamine-responsive megaloblastic anemia (TRMA) syndrome is a rare autosomal recessive disorder defined by the occurrence of megaloblastic anemia, diabetes mellitus, and sensorineural deafness, responding in varying degrees to thiamine treatment. Other features of this syndrome gradually develop. We describe three TRMA patients with heart rhythm abnormalities and structural cardiac anomalies. Eight other reported TRMA patients also had cardiac anomalies. Recently, the TRMA gene, SLC19A2, was identified, encoding a functional thiamine transporter. Characterization of the metabolic defect of TRMA may shed light on the role of thiamine in common cardiac abnormalities.
We evaluated the usefulness of patent ductus arteriosus (PDA) occlusion using a new catheter that combines good angiographic properties, easy manipulation across the duct, documentation of aortic and pulmonary artery pressure, and coil delivery for percutaneous transaortic ductal occlusion. Thirty patients (13 females and 17 males) who met the clinical and echocardiographic criteria for the percutaneous closure of PDA were catheterized. The patients selected for this study had a small to moderate PDA with a conal or tubular shape, adequate aortic ampula, and normal or mildly elevated pulmonary artery pressure. The median age was 4.8 years (range, 10 months-20 years). Patients were catheterized by the transaortic approach using the new angiographic and coil delivery catheter specially designed for this procedure. A PDA was closed in every case. A single DuctOcclud pfm coil was delivered in 28 patients, and 2 patients had NitOcclud pfm coils for ductal occlusion. The screening time was measured and found to be 50% less than the measured screening time using other catheters in our laboratory. Only one catheter and one guidewire were used per procedure, with no need for exchange wires or the establishment of an arteriovenous loop. The procedure time was also reduced by 50%. A minimal residual shunt, demonstrated by color-flow Doppler mapping, was present in 2 patients. The new combined angiographic and coil delivery catheter is most suitable for transaortic PDA coil occlusion, significantly decreasing the procedure and screening time.
We describe a unique case of a child who, since birth, has had a heart tumor at the atrioventricular junction associated with second degree atrioventricular block. The tumor is probably a rhabdomyoma.
Three hybridomas producing monoclonal antibodies specific for the mycoplasma-like organism (MLO), pathogenic agent of grapevine flavescence dorée, were obtained after fusion between spleen cells from a mouse immunized against flavescence dorée MLO and Sp2/O-Ag-14 mouse myeloma cells. These hybridomas were selected in an indirect sandwich ELISA in which antibodies from two different animal species were used (rabbit and mouse). This assay is convenient for anti-MLO monoclonal antibody screening, because of its sensitivity, specificity and good preservation of antigens. The three monoclonal antibodies were examined for reactivity towards the MLO causal agents of 15 plant yellows. None of the three were implicated in a serological relationship between the MLO of these plant yellows and flavescence dorée-MLO. Reactivity of the three monoclonal antibodies was checked towards two other isolates of flavescence dorée. One of the three antibodies detected the wild isolates.