Search PubMed⌕ Search

Biomedical subjects

Y Weinstein

Publications and source records attributed to Y Weinstein.

At least 37 records · Page 2Linked to original sources
PubMed1995

Structural and functional analysis of the promoter of the murine V gamma 1.1 T cell receptor gene.

The expression of the germ-line gene V gamma 1.1-C gamma 4 of the T cell receptor (TcR) gamma chain depends on interleukin (IL)-3 induction in hematopoietic cells, while in T cells, the rearranged gene is expressed constitutively. To understand the mechanism that controls TcR gamma gene expression, we cloned and characterized the structure and function of the V gamma 1.1-C gamma 4 TcR promoter. IL-3-dependent cell lines and T cell lines utilized the same transcriptional start sites. In chloramphenicol acetyltransferase (CAT) assays, the minimal 70-bp promoter confers strong transcriptional activity which is 50-60% of the Moloney long terminal repeat promoter activity. The 500-bp promoter region linked to the CAT gene exhibits IL-3 dependency similar to the endogenous TcR gamma gene. The immediate 3' and 5' flanking sequences inhibit the promoter activity two- to fourfold. The promoter lacks an obvious TATA box or CAAT box sequences, but contains a GC box in the untranslated region 3' to the promoter. The GC box is the core sequence of the element which binds Sp1-like proteins. Cloning of this Sp1 binding element in front of the thymidine kinase (TK) promoter and mutations generated in this site demonstrate its function as a silencer. Ultraviolet cross-linking analysis with the Sp1 binding site from the TcR gamma promoter revealed binding of a 90-100-kDa protein in a T cell line (EL-4) and 40-50 and 90-100-kDa proteins in FDC-P1 cells. The possible function of the Sp1-like protein in silencing the minimal promoter activity is discussed.

3T3 Cells↗
PubMed1995

Regulation of mental states and biofeedback techniques: effects on breathing pattern.

The purpose of the present study was to examine whether breathing pattern may be used as a reliable index for the effectiveness of techniques applied for the regulation of mental states. Heart rate (HR), breathing pattern, galvanic skin response (GSR), and electromyogram (EMG) of the frontalis muscle were measured in 39 male and female subjects aged 18-25 years during 10-minute treatment with relaxation technique (autogenic training and/or music) followed by 10 minutes of imagery training. In the first 7 sessions biofeedback (BFB) was not included, while during the last 6 sessions BFB was introduced and utilized by the subjects. Relaxation (music or autogenic training) led to a decrease in breathing frequency, attributed to lengthening of expiration time, as well as reduced HR, GSR, and frontalis EMG response. In most instances imagery training was related to an increase in these indices. Specifically, significant tachypnea was observed during imagery of sprint running. In most cases BFB substantially augmented the physiological responses. In conclusion, our data suggest that, compared with HR, GSR, and EMG responses, the breathing pattern is at least as sensitive to the mental techniques employed, and may be useful as a psychophysiological index for diagnosis and testing, especially in sport practice.

Adult↗
PubMed1995

Blood lactate concentration following exercise: effects of heat exposure and of active recovery in heat-acclimatized subjects.

The purpose of this study was to examine the effect of ambient heat on the decrease in blood lactate concentration ([LA]bl) during passive and during active recovery. Ten trained men performed six 1-min bouts of exercise at 100% VO2peak on a cycle ergometer, with 1-min rest between the bouts. Each subject exercised twice in thermoneutral (22 degrees C, 40% RH, TN), and twice in hot (35 degrees C, 30% RH, H) conditions. Exercise was followed by either 40 min of passive recovery (sitting) or by 20 min active recovery (cycling at 35% VO2peak) and 20 min passive recovery, named thereafter, 'active recovery'. Capillary blood lactate was measured before, 1 min after, and every 5 min during recovery. Heart rate (HR), rectal and skin temperatures (Tre, Tsk) were monitored continuously. VO2 was measured prior to exercise, during the last exercise bout, the first 10 min of recovery, and periodically thereafter. Post-exercise [LA]bl was similar in all treatments (13.5 +/- 1.8, 13.0 +/- 1.3, 14.8 +/- 4.1, 13.3 +/- 2.6 mmol.l-1 for TN-active, TN-passive, H-active and H-passive, respectively). [LA]bl was significantly lower during active, compared to passive recovery in both, TN and H conditions. Environmental heart did not independently affect [LA]bl during passive or active recovery. Exercise resulted in an elevation in Tre in all treatments, with a significantly higher Tre during active recovery in H compared to the other sessions. Likewise, no differences in HR and in VO2 were observed between H and TN conditions during active nor during passive recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Acclimatization↗
PubMed1995

Tyrosine phosphorylation of measles virus nucleocapsid protein in persistently infected neuroblastoma cells.

Subacute sclerosing panencephalitis is a slowly progressing fatal human disease of the central nervous system which is a delayed sequel of measles virus (MV) infection. A typical pathological feature of this disease is the presence of viral ribonucleocapsid structures in the form of inclusion bodies and the absence of infectious virus or budding viral particles. The mechanisms governing the establishment and maintenance of a persistent MV infection in brain cells are still largely unknown. To understand the mechanisms underlying MV persistence in neuronal cells, a tissue culture model was studied. Clone NS20Y/MS of the murine neuroblastoma C1300 persistently infected with the wild-type Edmonston strain of MV secretes relatively high levels of alpha/beta interferon (IFN). As shown previously, treatment of the persistently infected cultures with anti-IFN serum converted the persistent state into a productive infection indicated by the appearance of multinucleated giant cells. In this study, we have investigated whether alpha/beta IFN produced by NS20Y/MS cells activates cellular protein tyrosine kinases which will induce tyrosine phosphorylating activity specific to virus-infected cells. We present data to show augmented protein tyrosine kinase activity in the persistently infected cells. We demonstrate that the MV N protein is phosphorylated on tyrosine in addition to serine and threonine in the persistent state but not in NS20Y cells acutely infected with MV.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Factors affecting differences in supine, sitting, and standing heart rate: the Israeli CORDIS Study.

BACKGROUND: Measuring postural changes is among the simplest methods to elicit basic cardiovascular responses from patients who should not be subjected to treadmill stress testing. We attempted to clarify the individual factors that may affect these changes in resting heart rate (HR). METHODS: In a cross-sectional study, 6016 employees in Israeli industries were screened during 1985-87 for cardiovascular disease risk factors (The CORDIS Study). Measures of resting HR (supine, sitting, and standing) were obtained from 5428 subjects. The association between the HR differences for different postures and age, sex, height, body mass index, blood pressure level, health related habits, environmental temperature, and time of the day was analyzed. RESULTS: The difference in HR between supine and standing position was found to be greater among women than men (12.7 vs. 11.6%, p < 0.03). It was independently positively associated with height (p < 0.0001), cigarette smoking (p < 0.0001), and coffee drinking (p < 0.001), and inversely associated with age (p < 0.002), blood pressure level (p < 0.0005), and physical activity at work (p < 0.0001). CONCLUSION: The interindividual variability in HR response to different postures is partially explained by individual variables such as age, sex, height, blood pressure level, and health-related habits.

Adult↗
PubMed1994

Linkage localization of the thoraco-abdominal syndrome (TAS) gene to Xq25-26.

The thoraco-abdominal syndrome (TAS) presents a closure defect confined to the ventral midline, manifested as ventral hernia of various degrees in all affected individuals and antero-lateral diaphragmatic defect manifested almost exclusively in affected males. The syndrome is inherited as an X-linked dominant trait affecting blastogenesis (XLB mutation). We studied 27 members of the TAS family for linkage on the X chromosome. The best lod score of 5.5 at theta 0.04 was found for the HPRT locus on Xq26.1. A multilocus lod score of 12.4 was observed when the linkage analysis utilized additional markers in Xq25-26.

Abdomen↗
PubMed1992

Elevated activities of protein kinase C and tyrosine kinase correlate to leukemic cell aggressiveness.

We report a linkage between cell aggressiveness, protein kinase C (PKC) activity, tyrosine kinase (PTK) activity and serum requirement. We used 2 leukemic cell lines induced by Moloney murine leukemia virus (MLV). One line was highly aggressive (BS-24-1) and required low serum concentrations (3%) for optimal growth in comparison to the less aggressive line (RO2T) that needed 10% serum for optimal growth. The more malignant cells exhibited higher PKC and PTK activity. This activity was independent of serum concentration between 0.01-10%. In contrast, the weakly malignant cells need a high serum concentration (10%) for optimal PKC or PTK activity. Immunoblot analysis revealed a higher level of PKC protein in the BS-24-1 cells than in the RO2T cells. Serum induction of PKC activity did not change the amount of PKC protein in the cytosol or the membrane fractions, indicating post-translational mechanism regulation of PKC. We suggest that the aggressiveness of BS-24-1 resulted from its ability to become independent of growth regulation by serum factors, via autocrine stimulation of PKC and PTK.

Animals↗
PubMed1992

Oligoclonality of Moloney leukemias.

Induction of leukemia by non-transforming retroviruses results in the appearance of various hematopoietic tumors. It is believed that these tumors are monoclonal. In this work, the clonal nature of Moloney leukemia virus (MoLV)-induced tumors was studied. Two genetic parameters were used in order to identify leukemic clones: the pattern of the proviral integration sites and the rearrangement of the T-cell receptor complex (TCR). In more than 60% of the mice, different leukemic clones populated tumors developed in different organs of the same animal. Genotypic analysis of cell lines derived from a leukemic organ revealed that the tumor is composed of more than one clone. Phenotypic analysis of subclones which were derived from a monoclonal cell line showed variability in the expression of the Thy 1.2 and MHC antigens. The results indicate that MoLV-induced tumors are of oligoclonal nature. Each leukemic organ contains a mixture of leukemic clones, of which one is dominant.

Animals↗
PubMed1991

Effect of an iron supplement on body iron status and aerobic capacity of young training women.

Serum iron deficiency has a high incidence in female athletes. We investigated the effects of a daily oral iron supplement, (160 mg) administered during an intensive 7-week physical training programme, on body iron status, and the maximal aerobic capacity (VO2max) of 13 women (group A) compared to 15 who took a placebo (group B). The subjects were 19 years old. Blood samples were obtained before training began and on days 1, 7, 21 and 42 of training. They were analysed for packed cell volume (PVC) and for haemoglobin (Hb), 2,3-diphosphoglycerate (2,3-DPG), haptoglobin, iron and ferritin concentrations. The VO2max was measured on days 0, 21 and 42 of training. Following 21 days of training Hb, PCV and ferritin were significantly higher (P less than or equal to 0.01) in group A compared to group B. Over the training period Hb rose by 9.3% and 2.4% in groups A and B, respectively. At the end of training 66% of group B exhibited ferritin concentrations below 10 ng.ml-1, while none of group A had such low values. Mean VO2max of group A had increased by 7.5% following 21 days of training (P less than or equal to 0.01) and by 15.3% after 42 days. No appreciable increase in VO2max had occurred in group B by day 21 (significantly lower than VO2max of group A; P less than or equal to 0.05), however by day 42 it had increased by 14.3% (P less than or equal to 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Reexamination of Stewart's quantitative analysis of acid-base status.

To provide experimental verification to Stewart's quantitative approach to acid-base analysis, the effects of acute maximal treadmill exercise (VO2max test) on venous acid base status were studied in 17 male subjects aged 18-23 yr. Venous CO2 tension (PCO2) total plasma proteins ([PTOT]), [H+], and concentrations of strong ions [( Na+], [K+], [Cl-] and lactate ion concentration ([La-]) were measured before and within 1 min post-exercise. Mean post-exercise PCO2, [PTOT], [K+], and [La-] were significantly higher than the corresponding pre-exercise values (P less than 0.05), there was a strong tendency for a significant change in [Na+] (P less than 0.056), and no changes were found in [Cl-]. Changes in venous acid-base status were analyzed quantitatively by applying relevant physicochemical theory. Altered values measured in the independent variables ([PTOT], PCO2, and net strong ion difference, [SID]) were used to calculate the corresponding changes in the dependent quantities. Comparison of individual measured and calculated values for the only one of these that is normally measured, ([H+]), yielded the theoretically expected agreement. PCO2 and [SID] changes accounted for most [H+] changes. These results demonstrate the usefulness of the quantitative approach (i.e., [H+]-PCO2 diagram) in the analysis and in understanding of plasma acid base changes with exercise and in clinical situations.

Acid-Base Equilibrium↗
PubMed1990

Changes in the coding sequence of the H-2Dk gene of metastatic cells that might account for immunogenic abnormality of its encoded antigen.

In previous studies we have demonstrated that metastatic cells, derived from T-10 fibrosarcoma, express an immunogenically abnormal H-2Dk glycoprotein which is involved in manifesting their metastatic phenotype. In the present study we show that these cells contain a remarkably high level of H-2Dk specific mRNA. Moreover, by cloning cDNA of this gene and analyzing its nucleotide sequence, we found 4 single nucleotide changes. Two of them did not change the encoded amino acids, whereas the others resulted in two amino acid substitutions in the alpha-2 domain of the protein product that might account for its immunogenic abnormality.

Amino Acid Sequence↗
PubMed1990

Cloning, characterization and sequence of a novel 59-kDa protein of Chlamydia trachomatis.

Chlamydia trachomatis (Ct) serovar L2 DNA was partially digested with BamHI, ligated with plasmid vector pBR325 and used to transform Escherichia coli JMB83. Recombinant colonies were screened for their ability to synthesize chlamydial (chl) proteins by dot immunoblot and by in vitro transcription translation assays. A clone, B1, expressing a 59-kDa protein was further characterized, and the encoding gene was subcloned in the expression vector, pKK223-3, containing the tac promoter. Elevated levels of the 59-kDa protein were produced in E. coli in the presence of the lac inducer, IPTG. Sequencing identified one long open reading frame encoding a polypeptide of 59,075 Da (59 kDa). The partially purified 59-kDa protein was recognized by sera from patients with chl infections as shown in immunoblotting. In addition, the 59-kDa protein was located in the sarcosyl-soluble fraction of chl lysates. When used as a DNA probe in dot hybridization assays, the clone encoding the 59-kDa protein showed high homology to all serovars of Ct and four strains of Chlamydia psittaci. The cloned 59-kDa protein is neither related to the 60-kDa heat-shock protein found in many strains of bacteria, nor to the Cys-rich sarcosylinsoluble protein described in other studies of chlamydia.

Amino Acid Sequence↗
PubMed1990

Competition among leukemic cells.

We investigated competition among leukemic cells induced by Moloney murine leukemia virus (MoLV) in order to understand the mechanisms involved in the generation of leukemia. We used six leukemic cells lines from Balb/C mice infected with MoLV. Each line had a unique genetic marker which enabled us to trace it in mixtures of cells either in vivo or in vitro. The markers were a unique rearrangement of T-cell receptors, the integration sites of the retrovirus and rearrangements in the Pim-1 oncogene. A mixture of two cell lines (1:1) injected into intact Balb/C mice usually produced a monoclonal tumor originating from one cell line. In most cases, the cell lines that were aggressive in vivo were also dominant in mixing experiments in vitro. In some lines, we could correlate the aggressiveness of the tumor to its superior growth rate and lower requirement for serum factors in vitro. In others, this correlation did not hold, and we assumed that host factors like the immune system contribute to the malignant potential of the leukemic cell.

Animals↗
PubMed1989

Interleukin 3 (IL-3) induces transcription from nonrearranged T cell receptor gamma loci in IL-3-dependent cell lines.

The expression of the murine TCR-gamma genes was examined in a series of IL-3-dependent and growth factor-independent cell lines. All of the IL-3-dependent cell lines, but none of the IL-3-independent lines, expressed high levels of one or more of the gamma genes but did not express the TCR-beta genes. None of the cell lines expressing the gamma loci contained detectable genomic gamma gene rearrangements. Sequencing of cDNA clones from two of the cell lines demonstrated that transcription was from nonrearranged gamma loci based on the presence of sequences in the cDNAs that are found immediately 5' of the J gamma 4 and J gamma 2 genes. The expression of gamma transcripts was dependent upon IL-3 and no transcripts were detectable within 6-8 h after the removal of IL-3. Readdition of IL-3, but not granulocyte CSF, resulted in the reappearance of gamma transcripts within 30 min. The results demonstrate that IL-3 regulates the expression of nonrearranged gamma loci. Since expression is required for rearrangement, it can be hypothesized that IL-3 may influence the ability of lymphoid/myeloid progenitors to commit to the T cell lineage.

Animals↗
PubMed1989

Activation of the c-H-ras proto-oncogene by retrovirus insertion and chromosomal rearrangement in a Moloney leukemia virus-induced T-cell leukemia.

A rearrangement of the c-H-ras locus was detected in a T-cell line (DA-2) established from a Moloney leukemia virus-induced tumor. This rearrangement was associated with the high-level expression of H-ras RNA and the H-ras gene product, p21. DNA from DA-2 cells transformed fibroblasts in DNA transfection experiments, and the transformed fibroblasts contained the rearranged H-ras locus. The rearrangement involved one allele and was present in tissue from the primary tumor from which the cell line was isolated. Cloning and sequencing of the rearranged allele and comparison with the normal allele demonstrated that the rearrangement was complex and probably resulted from the integration of a retrovirus in the H-ras locus between a 5' noncoding exon and the first coding exon and a subsequent homologous recombination between this provirus and another newly acquired provirus also located on chromosome 7. These events resulted in the translocation of the coding exons of the H-ras locus away from the 5' noncoding exon region to a new genomic site on chromosome 7. Sequencing of the coding regions of the gene failed to detect mutations in the 12th, 13th, 59th, or 61st codons. The possible reasons for the complexity of the rearrangement and the significance of the activation of the H-ras locus to T-cell transformation are discussed.

Alleles↗
PubMed1988

Iron deficiency caused by 7 weeks of intensive physical exercise.

The present study was designed to evaluate the effect of an intensive physical training program involving both isometric and isotonic activities on the body iron status of 8 females and 11 males (age 20 +/- 1 year). The training was carried out over a 7 week period and included 8 h of varying physical activities each day. Venous blood samples were obtained from the subjects prior to the beginning of the training, on day 2 and in weeks 2, 4, 6 and 7 of the program. Blood samples were analyzed for iron, ferritin and hemoglobin (Hb) concentrations, total iron binding capacity (TIBC) and red blood cell count (RBC). Iron levels of males and females decreased 65% after 2 weeks of training (p less than 0.001). At the end of the training program 5 males and 6 females had lower than normal iron values (less than 13.4 mumol.l-1). TIBC increased 25% in women and 18% in men following 2 and 4 weeks of training (p less than 0.001) and remained at this elevated level throughout the training period. Ferritin levels decreased 50% in both sexes after 4 weeks of exercise (p less than 0.05) and remained at this level until the end of the training. Hb and RBC decreased 8-10% in both sexes during the training period. In two of the women anemia occurred after 4 weeks of training. The development of latent iron deficiency in a substantial number of participants after a relatively short period of training is uncommon and may reflect the high intensity of exercise required in this program.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗