Biomedical subjects
Publications and source records attributed to Y Schwartz.
A case report of a patient with acute myocardial infarction and severe hypoxemia due to acute right to left interatrial shunt (RLIAS) is presented. Diagnostic and therapeutic procedures are discussed.
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The study presents a method for identifying endocardial electrical features relevant to local ischaemia detection at rest. The method consists of, first, normalisation of electrograms to a uniform representation; secondly, the use of principal component analysis to reduce the dimensionality of the electrogram vector space; and, thirdly, a search for a classification axis that matches the degree of ischaemia present in the tissue. Left ventricular myocardial states were assessed by echocardiography and NOGA mapping in eight dogs at baseline and then immediately after, 5h after and 3 days after occlusion of the left anterior descending coronary artery. Five principal components were required to approximate electrograms with an average error of less than 10% of the peak-to-peak amplitude. Correlations of 0.77, 0.80 and 0.84 were obtained between the principal component-based parameters and the echocardiography scores at the three ischaemic stages, respectively. Expression of these parameters in the time domain showed that the major changes occurred in the depolarisation segment of the endocardial electrogram as well as in the ST-segment. In conclusion, the proposed method provides a suitable alternative co-ordinate system for the classification of ischaemic regions and highlights signal segments that change as a result of pathology.
BACKGROUND: While the overexpression of c-erbB gene family in several malignancies is associated with poorer prognosis, the association between the expression of the cellular markers and the response to chemotherapy is not yet clear. In this study we investigated the expression of c-erbB-4 receptor in NSCLC and correlated it with the response to gemcitabine-cisplatin combination chemotherapy. PATIENTS AND METHODS: Forty-three NSCLC patients with histologically or cytologically proven disease were treated with gemcitabine-cisplatin combination chemotherapy. Immunohistochemical stains for c-erbB-4 receptor were performed in 20 cases on paraffin sections using the avidin-biotin-peroxidase method. RESULTS: Two patients achieved complete response (5%), and 16 achieved partial response (37%) yielding an overall objective response rate of 42%. Minimal response was observed in seven patients (16%) and disease stabilization in 7%. Immunohistochemical stain was positive for the presence of c-erbB-4 receptor in 25% of patients, and negative in 75%. No response was documented in c-erbB-4 positive patients (0 of 5) while an objective response (complete, partial or minimal) was seen in 11 of 15 (73%) c-erbB-4 negative patients. Negative stain for c-erbB-4 significantly favored response to gemcitabine-cisplatin combination (P < 0.01). CONCLUSION: C-erbB-4 expression status showed no correlation with survival and cannot be accepted at this time as a guiding factor for therapeutic management. These interesting results deserve further evaluation in a large-scale prospective trial before treatment recommendations on the basis of c-erbB-4 presence can be finally made.
OBJECTIVES: To characterize the incidence of patients with primary pulmonary hypertension (PPH) in Israel and their outcomes. METHODS: We have evaluated retrospectively all the patients in Israel in whom PPH was diagnosed between the years 1988 and 1997. We looked at medical history, hemodynamic data, pulmonary function and gas exchange, and demographic variables. Patients were followed up for survival until November 1997. Life table analysis and Kaplan-Meier statistics were used to estimate the overall survival distribution. Regression analysis was used to examine the relations between survival and selected variables. RESULTS: Overall, we found 44 patients with PPH. The estimated incidence of PPH in Israel is 1.4 new cases per year per million population. The mean (+/- SD) age at diagnosis was 43 +/- 13 years. In the Jewish population, PPH was more frequent among immigrants from Europe and the United States. The mean interval from the onset of symptoms to diagnosis was 3 years (median, 2 years). The median survival time was 4 years. The 1-year, 3-year, and 5-year survival rates were 82%, 57%, and 43%, respectively. The major variables influencing the survival rate were the following: interval from symptom onset to diagnosis; and hemodynamic measurements (ie, mean pulmonary artery pressure, mean right atrial pressure, and cardiac index). In comparison to rates discerned from the National Institutes of Health registry data, the survival rate in Israel is somewhat better and prognosis is influenced by similar hemodynamic variables. CONCLUSION: PPH is a rare and fatal disease in Israel. New therapeutic modalities such as prostacyclin therapy and lung transplantation may improve survival among patients with this malignant disease.
On the basis of the reported efficacy of gemcitabine plus cisplatin in patients with non-small cell lung cancer (NSCLC), this combination has been selected to be given as our firstline service regimen for advanced or metastatic disease. Patients recruitment was almost unlimited: no exclusion criteria were made, except for disease-related Karnofsky's performance status below 50%, the presence of central nervous system or spinal involvement by uncontrolled metastases, or creatinine clearance below 50 ml/min. Cisplatin 30 mg/m2/day on days 1-3 and gemcitabine 1250 mg/m2/day on days 1, 8 and 15 every 4 weeks were given on an outpatient schedule to consecutive patients with locally advanced or metastatic NSCLC. Forty-three successive NSCLC patients with histologically or cytologically proven disease were treated. Adenocarcinoma was diagnosed in 35% of cases, squamous cell carcinoma in 60% and broncho-alveolar type in 5%. Smoking was mentioned by 63% of the patients. Numerous medical problems were recorded in 75% of the patients. Stage IIIB was observed in 10 of 43 patients, while metastatic disease was found in the rest. All the patients, except for two, were symptomatic. Two patients achieved complete response (5%) and 16 achieved partial response (37%), yielding an overall objective response rate of 42%. Minimal response was observed in seven patients (16%) and disease stabilization in 7%. Adding the objective response rate to the minimal response and stabilization rates, the disease-control (progression-free) rate reaches 65%. The time to progression ranged from 0 to 69 weeks in all the patients. The overall survival of the group ranged from 4 to 98 weeks, with a median of 45 weeks. Clinical benefit response was observed mainly in patients who also achieved an objective response. We conclude that outpatient cisplatin plus gemcitabine combination is feasible, efficacious and justified in patients with advanced or metastatic NSCLC.
BACKGROUND: Defining the presence, extent, and nature of the dysfunctional myocardial tissue remains a cornerstone in diagnostic cardiology. A nonfluoroscopic, catheter-based mapping technique that can spatially associate endocardial mechanical and electrical data was used to quantify electromechanical changes in the canine chronic infarction model. METHODS AND RESULTS: We mapped the left ventricular (LV) electromechanical regional properties in 11 dogs with chronic infarction (4 weeks after LAD ligation) and 6 controls. By sampling the location of a special catheter throughout the cardiac cycle at multiple endocardial sites and simultaneously recording local electrograms from the catheter tip, the dynamic 3-dimensional electromechanical map of the LV was reconstructed. Average endocardial local shortening (LS, measured at end systole and normalized to end diastole) and intracardiac bipolar electrogram amplitude were quantified at 13 LV regions. Endocardial LS was significantly lower at the infarcted area (1.2+/-0.9% [mean+/-SEM], P<0.01) compared with the noninfarcted regions (7.2+/-1.1% to 13. 5+/-1.5%) and with the same area in controls (15.5+/-1.2%, P<0.01). Average bipolar amplitude was also significantly lower at the infarcted zone (2.3+/-0.2 mV, P<0.01) compared with the same region in controls (10.3+/-1.3 mV) and with the noninfarcted regions (4. 0+/-0.7 to 10.2+/-1.5 mV, P<0.01) in the infarcted group. In addition, the electrical maps could accurately delineate both the location and extent of the infarct, as demonstrated by the high correlation with pathology (Pearson's correlation coefficient=0.90) and by the precise identification of the infarct border. CONCLUSIONS: Chronic myocardial infarcted tissue can be characterized and quantified by abnormal regional mechanical and electrical functions. The unique ability to assess the regional ventricular electromechanical properties in various myocardial disease states may become a powerful tool in both clinical and research cardiology.
The FER locus in the mouse encodes two tyrosine kinases, p94fer and p51ferT. While p94fer accumulates in the cytoplasm and nucleus of most mammalian cells the expression of p51ferT is restricted to the nucleus of meiotic primary spermatocytes. The cellular function of the FER kinases is not understood, nor has a substrate for these enzymes been characterized. To identify putative substrates of p94fer and p51ferT, the two enzymes were used as 'baits' in the yeast two-hybrid screening system. cDNAs encoding the mouse TATA element modulatory factor (TMF) were repeatedly isolated in this assay. TMF was previously shown to bind the TATA element in RNA polymerase II promoters and impaired their functioning in a cell free transcription system. Both p94fer and p51ferT phosphorylated the TMF protein in in vitro and in vivo kinase assays. Sequential deletions showed that the carboxy-terminal region of TMF was essential for phosphorylation. In situ hybridization analysis revealed the preferential accumulation of TMF transcripts in meiotic spermatogenic and oogenic cells. p94fer and p51ferT may thus modulate the suppressive activity of TMF during cellular growth and in defined differentiation processes.
Oxygenated derivatives of cholesterol (oxysterols), found in high concentrations in atherosclerotic lesions, are potent immunosuppressive agents inhibiting T-cell responses to different stimuli. The action of oxysterols on macrophage functions and macrophage-lymphocyte interaction has been poorly investigated. In this work, the effects of 25-hydroxycholesterol (25-OHCh) and 7-ketocholesterol (7-KCh) upon some functions of murine peritoneal macrophage (PM), such as generation of reactive oxygen intermediates (ROI), secretion of neopterin and interleukin-1 (IL-1)-like activity, Fc-receptor (FcR) activity, and murine and human lymphocyte functions, participating in lymphocyte-macrophage interactions, such as macrophage-activating factor (MAF) and Ia-inducing factor (IaIF) secretion, were studied in vitro. 7-KCh in concentration of 5 micrograms/mL culture medium only, but not 25-OHCh, significantly inhibited ROI generation by zymosan-stimulated PM. Pretreatment of PM for 22 h with 25-OHCh and 7-KCh led to the decrease of IL-1-like activity secretion. 25-OHCh and 7-KCh inhibited both FcR-dependent binding and phagocytosis of sheep red blood cells (SRBC). Oxysterols did not change both spontaneous and lipopolysaccharide-stimulated secretion of neopterin by PM. 25-OHCh dose-dependently and more efficiently than 7-KCh inhibited murine splenocyte secretion of MAF, which activity was determined by the ability of splenocyte-conditioned medium to stimulate ROI generation in PM. Both 25-OHCh and 7-KCh inhibited significantly proliferative activity of human mixed lymphocyte culture (MLC), as well as lymphocyte secretion of IaIF, which stimulates the expression of HLA antigens in cultured human monocytes. Purified Ch did not alter these parameters. These data showed, that some inflammatory functions of macrophages and lymphocytes may be modified by such environmental conditions as the presence of oxysterols.
In vivo, GH and insulin usually produce opposing effects on carbohydrate and lipid metabolism in adipocytes, even though their signal transduction pathways overlap. However, when added to rat adipocytes that have been made GH deficient, GH briefly produces responses that are qualitatively like those of insulin. Subsequently, GH induces refractoriness to this acute insulin-like response, in a sense restricting its effects to a unique subset of possible physiological actions. Okadaic acid is an inhibitor of type I and IIa phosphoprotein phosphatases and affects glucose metabolism in fat cells in a manner that is reminiscent of GH. Okadaic acid initially mimics the actions of insulin, and subsequently, even after it has been removed by thorough washing, blunts the ability of adipocytes to accelerate glucose metabolism in response to insulin or GH. Because refractoriness to the insulin-like effect of GH is associated with GH-induced increases in intracellular free calcium concentrations ([Ca2+]i), we examined the effects of insulin on [Ca2+]i in okadaic acid-treated adipocytes. Adipocytes were incubated with 0.25 microM okadaic acid for 1 h, washed, and reincubated without okadaic acid for 2 h before measurement of [Ca2+]i using fura-2 as a calcium indicator. Neither GH (500 ng/ml) nor insulin (100 microU/ml) affected [Ca2+]i in cells in which glucose metabolism was stimulated, but both hormones rapidly increased [Ca2+]i in adipocytes that were refractory to insulin-like stimulation. The characteristics of the increase in [Ca2+]i produced by insulin were identical to those previously reported for GH. The effect of insulin was mimicked by the dihydropyridine calcium channel activator BayK 5552 or depolarization of the cell membrane with 30 mM KCl and was blocked by the dihydropyridine calcium channel blocker, nimodipine (100 nM), implicating activation of voltage-sensitive L-type Ca2+ channels. The increase in [Ca2+]i was also mimicked by sn-1,2-dioctanoylglycerol and blocked by inhibitors of protein kinase C (staurosporine, chelerythrine chloride, and calphostin), and D609, an inhibitor of phospholipase C, as reported for GH. Acquisition of the ability to increase [Ca2+]i in response to insulin required a lag period of at least 2 h after removal of okadaic acid and was prevented by inhibitors of RNA and protein synthesis. Adipocytes that were incubated with inhibitors of protein kinase A (KT-5720), or protein kinase C (staurosporine) along with okadaic acid also failed to increase [Ca2+]i in response to insulin. Conversely, adipocytes that were incubated with dibutyryl cAMP, methylisobutyl xanthine, or phorbol ester instead of okadaic acid increased [Ca2+]i when treated with insulin 2 h later. These results suggest that phosphorylated substrates of protein kinases A and C may mediate the transcriptional event(s) that enable adipocytes to activate L-type Ca2+ channels in response to insulin. Blockade of protein kinases A or C or removal of calcium from the incubation medium did not restore the ability of okadaic acid-treated adipocytes to increase glucose metabolism in response to insulin, nor did pretreatment of adipocytes with dibutyryl cAMP or phorbol ester decrease insulin-induced stimulation of glucose metabolism. The failure of insulin to increase glucose metabolism in okadaic acid-treated adipocytes thus cannot be ascribed to the increase in [Ca2+]i. These findings indicate that just as GH can produce an insulin-like response, so too can insulin produce a GH-like response, and highlight the need to understand how specificity of hormone action is achieved in cells that respond to different hormones that share elements of their transduction pathways.
Two variants of the human myeloid leukemia cell line HL-60 were used to study the possible involvement of the IFN-induced protein 2-5A synthetase in cell growth arrest and differentiation. The two variants, HL-205 and HL-525, are equally susceptible to differentiation to the granulocyte lineage by exposure to DMSO, but only HL-205 cells acquire the macrophage phenotype following exposure to phorbol esters. The kinetics of 2-5A synthetase activity was established in both variants exposed to either DMSO or phorbol 12-myristate 13-acetate. With DMSO treatment, 2-5A synthetase activity was markedly induced in both variants, although with slightly different kinetics. With phorbol 12-myristate 13-acetate treatment, 2-5A enzymatic activity increased only in HL-205; no activity was detected up to 96 h after treatment in HL-525. The induction of 2-5A synthetase activity is apparently alpha/beta-IFN dependent, because only antibodies directed against a mixture of alpha- and beta-IFN completely abolished the increase in activity detected during differentiation of HL-205 cells. To directly establish the role of 2-5A synthetase in differentiation, HL-205 cells were transfected with an expression vector harboring the cDNA for the 43-kDa isoform of murine 2-5A synthetase fused to the inducible metallothionein promoter. Two clones, clone 6, which yielded a low level of 2-5A synthetase activity in response to ZnCl2 (which activates the promoter), and clone 7, which was a high responder, were further analyzed and compared with the control clone, neo. Reductions in the rates of cell growth and thymidine incorporation were observed with both clone 6 and clone 7 cells exposed to ZnCl2; clone 7 was more responsive. In addition, the level of c-myc-specific RNA transcript was greatly reduced in ZnCl2 or beta-IFN-treated clone 7 cells, whereas the neo cells responded similarly only after beta-IFN treatment. Treatment of clone-neo cells with beta-IFN resulted in conversion of pRb protein from the phosphorylated to the underphosphorylated form within 24 h; ZnCl2 had no effect, even after 72 h. In contrast, the accumulation of the underphosphorylated form of pRb was observed in clone 7 cells treated either with beta-IFN or ZnCl2. Finally, a significant increase in nitro blue tetrazolium-positive cells, an indication of differentiation, was evident with ZnCl2-treated clone 6 and clone 7 cells; no such increase was observed with clone-neo cells under similar conditions. We conclude that ectopic expression of 2-5A synthetase in HL-205 cells results in cell growth arrest and facilitates the appearance of a myeloid differentiation marker.
Immunohistochemical peroxidase staining for p53 protein was performed on 22 condyloma acuminatum tissue samples from patients infected with human papillomavirus (HPV). The purpose of our study was to understand the benign character of this syndrome. The patients studied were infected by HPV type 6 and 11. Two monoclonal antibodies, PAbs DO-1 and 240, were used to detect the p53 protein. Overexpression of wild-type p53 was found in the nuclei of the basal cell layers. In healthy tissues and non-infected patients no p53 protein expression was detected. We would like to speculate that infection with HPVs and their viral protein E7, which is implicated in disruption of normal growth, may regulate the induction of wild-type p53 over-expression, as is known for DNA-damaging agents such as UV- or X-radiation.
Polychemotherapy appears to increase survival moderately but at a cost of severe toxicity, mainly due to cisplatin. New platinum salts (chiefly carboplatin) have therefore been developed. This review on the use of carboplatin in advanced-stage urothelial tumours was undertaken to find the actual place of carboplatin in the treatment of these tumours, and to describe its best use in polychemotherapy. In 322 patients, carboplatin alone gave 12.9% objective responses (OR), 2.5% complete responses (CR) and 10.4% partial response (PR). Many polychemotherapy protocols were used, most frequently carboplatin/methotrexate/vinblastin. The results were OR: 63%, CR: 19%, PR: 44% among 146 patients. These results confirm the relative efficiency of carboplatin on urothelial tumours, particularly when used in combination. Because of the lack of prospective studies and the wide disparity in the doses and in the dose adjustment, no comparison can be made with cisplatin. Carboplatin has virtually no renal toxicity at the usual doses, and does not require hyperhydratation. The pharmacokinetic behaviour of the two platinum salts is highly different, as carboplatin does not undergo tubular metabolism. The efficiency and tolerance of carboplatin used to be optimised by adapting the dose to the glomerular filtration rate, as was shown for germ cell tumours. In conclusion, these considerations fully warrant further clinical trials of carboplatin.
Adiposis dolorosa is a disease characterized by painful, subcutaneous fatty tumors. This disorder usually occurs in obese, postmenopausal women and is associated with weakness and mental disturbances such as depression, confusion, lethargy, and dementia. The cause is unknown, and there is no specific treatment. Pain may be relieved by steroids, intravenous lidocaine, or analgesics. Surgical treatment consists of excision or liposuction of the painful masses. We present two cases of adiposis dolorosa in men, with a follow-up of more than 10 years.
Adipocytes that have been preincubated for 3 h or more in hormone-free medium respond to GH with a transient insulin-like increase in glucose metabolism, followed by a period of refractoriness to further insulin-like stimulation. Adipocytes freshly isolated from normal rats and adipocytes that were exposed to GH in the first hour of a 4-h incubation period are refractory to this insulin-like effect. Because earlier studies revealed a relationship between refractoriness and cellular calcium, we examined the effects of GH on the intracellular calcium concentration ([Ca2+]i) under a variety of conditions in which sensitivity to insulin-like stimulation or refractoriness is known to be affected. A dual nitrogen laser imaging microscope with computer-assisted image processing to measure fluorescence changes in individual adipocytes loaded with fura-2 AM was used to measure [Ca2+]i. After prolonged incubation in vitro, resting [Ca+2]i was 120 +/- 6 nM and remained unchanged for more than 1 h after the addition of 100 ng/ml human GH (hGH), which doubled the rate of incorporation of [3-3H] glucose into triglycerides in this interval. Lipogenesis declined in the second hour, and [Ca+2]i slowly increased, reaching 324 +/- 49 nM by the end of the third hour (P less than 0.05). When added with GH, actinomycin-D, an inhibitor of RNA synthesis, caused the accelerated rate of lipogenesis to persist for at least 5 h and blocked the delayed increase in resting [Ca+2]i. Resting [Ca2+]i in freshly isolated, and hence refractory, adipocytes was 342 +/- 34 nM and declined to 112 +/- 11 nM concomitant with acquisition of insulin-like sensitivity to GH. The addition of 100 ng/ml hGH to these cells at the beginning of incubation, under conditions known to sustain refractoriness prevented the decline in resting [Ca2+]i and enabled them to exhibit a further acute increase in [Ca2+]i in response to a second exposure to hGH in the fourth hour. When added 60 min after GH, actinomycin-D blocked the ability to raise [Ca2+]i acutely in response to GH, but did not interfere with GH's action to sustain resting [Ca2+]i, which remained at about 300 nM. The concentration of GH needed to increase [Ca2+]i acutely in refractory cells is about 6-fold higher than that needed to maintain resting [Ca+2]i. Differences in the time of sensitivity to actinomycin-D and dose dependency suggest that sustaining resting [Ca2+]i and production of the acute increase in [Ca2+]i are separate phenomena.(ABSTRACT TRUNCATED AT 400 WORDS)
The status of osteoarticular tuberculosis in recent years was studied. 82 cases diagnosed here between 1951-1985 were surveyed. The disease was more common among East European Jews (38%) and among young people: the mean age was 36 years and the highest incidence was in the third decade. A secular tendency to "aging" was noted, as in later years the mean age increased. However, there was also a secular decrease in incidence, explained by a progressive decrease in immigration to Israel. The disease affected most commonly the spinal vertebrae and the weight-bearing joints. There was an average delay of 19 months between onset of symptoms and/or signs of the disease and its diagnosis.
In adipocytes that have been deprived of growth hormone (GH) for at least 3 hr, GH elicits a transient insulin-like response that is followed by a period of refractoriness to further insulin-like stimulation. Exposure of adipocytes to GH in the first hour of a 3-hr incubation prevents the appearance of insulin-like sensitivity. Intracellular Ca2+ concentration [( Ca2+]i) was measured in individual adipocytes that were loaded with fura-2 hexakis(acetoxymethyl) ester after preincubation in the presence (refractory) or absence (sensitive) of recombinant human GH at 100 ng/ml. Using a dual nitrogen laser imaging microscope with computer-assisted image processing to measure fluorescence changes, we observed that resting [Ca2+]i was 220 +/- 10 nM in refractory adipocytes and 110 +/- 6 nM in sensitive adipocytes (P less than 0.001). GH had no acute effect on [Ca2+]i in sensitive adipocytes but caused a sustained 3-fold increase in [Ca2+]i in refractory cells within 3 min (P less than 0.001). Insulin did not change [Ca2+]i in either sensitive or refractory adipocytes. In refractory cells treated with insulin and GH simultaneously, insulin completely blocked the rise in [Ca2+]i due to GH. Oxytocin elicited a prompt increase in [Ca2+]i followed by a quick return to resting levels in both sensitive and refractory cells. These findings indicate that basal [Ca2+]i is increased in refractory cells and that GH produces a sustained rise in [Ca2+]i only in refractory adipocytes. We suggest that the sustained increase in [Ca2+]i produced by GH in refractory cells prevents the expression of the insulin-like response.
Adipocytes are physiological targets for GH in both growing and nongrowing individuals. In adipocytes that have been deprived of GH for at least 3 h, GH initially produces a response that is characterized by increased metabolism of glucose and inhibition of the lipolytic effects of catecholamines. This insulin-like effect disappears within 2-3 h despite continued stimulation and cannot be elicited again unless cells are deprived of GH for at least 3 h. Despite refractoriness to the insulin-like action of GH, the lipolytic effect of GH is evident at this time. Although termination of the insulin-like response and induction of both refractoriness and lipolysis all depend upon synthesis of RNA and proteins, these 3 effects of GH appear to be neither temporally nor causally related. Scatchard analysis of ligand binding data suggests that these various effects are produced by interaction of GH with a single class of receptors. However, since modification of either the hormone or the carbohydrate moiety of the receptor can selectively attenuate either the insulin-like or the lipolytic response, more than one hormone receptor interaction is likely. Northern analysis indicates the presence of at least 2 alternately spliced mRNA transcripts for the GH receptor, and at least 3 different complexes are seen after GH is covalently crosslinked to intact adipocytes. Refractoriness does not result from changes in either the number or affinity of GH receptors, but may result from increased cytosolic calcium. Although the protein kinase C activator phorbol myristate acetate mimics both the insulin-like and lipolytic actions of GH, increased activity of protein kinase C probably does not mediate either action of GH. The intracellular mediators of the diverse actions of GH are unknown at this time.