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Biomedical subjects

J Stein

Publications and source records attributed to J Stein.

At least 217 records · Page 12Linked to original sources
PubMed1996

Gouty arthritis in nodal osteoarthritis.

OBJECTIVE: To analyze the clinical features and identify factors associated with the development of gouty arthritis in nodal osteoarthritis (OA). METHODS: Thirty-two consecutive patients (21 women and 11 men, mean age 75.8 years) with both nodal OA and crystal proven acute gout and/or tophi of distal/proximal interphalangeal (DIP/PIP) joints were studied between 1986 and 1994. RESULTS: Tophi of DIP and/or PIP joints were present in 29 (90%) patients; alone in 9 and together with acute DIP or PIP gouty arthritis in 20. Three patients had acute DIP or PIP gouty episodes but no digital tophi. Mean pretreatment serum urate was 614.9 +/- 163.2 (range 422-1088 mumol/l). Risk factors for gout included diuretic use (81%), renal failure (59%), hypertension (66%), alcoholism (22%), prophylactic low dose ASA (20%), and a positive family history (16%) of patients. CONCLUSION: The coexistence of gouty arthritis in nodal OA is important to recognize and treat, particularly in elderly women with renal failure, hypertension, or cardiac failure who are receiving longterm diuretic therapy.

Acute Disease↗
PubMed1996

[Measurement of fecal elastase 1 by immunoreactivity: a new indirect test of the pancreatic function].

AIM: The aim of this study was to evaluate the potential and precision of the fecal elastase type 1 rest in comparison to the secretin-pancreozymin-test in the diagnosis of exocrine pancreatic insufficiency. METHODS: We studied 254 stool samples from 102 individuals without malabsorption (n = 53) and patients with pancreatic maldigestion syndromes (n = 49). Pancreatic elastase was measured immunologically, using a new enzyme immunoassay according to the sandwich technique. RESULTS: Spot stool immunoreactive elastase activity in controls ranged from 136 to 4,400 micrograms/g. Ninety five percent of all values where within 175 to 1,500 micrograms/g. The lower limit of normal was defined as 150 micrograms/g. No significant decrease of immunoreactivity was found when stool samples were stored at room temperature over five days. The assay variability calculated from 10 consecutive assays of a single fecal sample gave coefficients of variation ranging from 3.3 to 6.3% for intraassay-variability and from 4.1 to 10.2% for interassay-variability. There was a good correlation between the output of elastase compared to lipase output with correlations coefficients of 0.821 in controls and 0.905 in patients with impaired pancreatic function. In stool samples of 49 patients with exocrine pancreatic insufficiency the concentration of fecal elastase was significantly lower (P < 0.001) compared to controls and patients with Crohn or coeliac disease. Elastase immunoreactivity showed higher sensitivity and specificity as compared to fecal chymotrypsin. Furthermore, in contrast to fecal chymotrypsin, the test results were unaffected by pancreatic enzyme replacement therapy. CONCLUSION: These results indicate that fecal immunoreactive elastase may be recommended as a new, non-invasive easy-to-perform tubeless pancreatic function test with a high sensitivity and specificity in comparison with healthy controls.

Adolescent↗
PubMed1996

Bile acid-induced increase of rat colonic apical membrane fluidity and proton permeability.

Rat colonic brush-border membrane vesicle fluidity and passive proton permeability were studied after in vitro exposure to chenodeoxycholate (CDC), taurochenodeoxycholate (TCDC) and taurocholate (TC). The bile acids caused significantly concentration-related increases in colonic membrane fluidity measured by the fluorophore DPH, which is reflecting the fluidity of all membrane layers, but not by 2-AS and 12-AS, which are reflecting the fluidity of the outer membrane layers, indicating that alterations of the membrane fluidity may appear at the inner membrane. Proton permeability (Pnet) of the membranes was increased by the three bile acids CDC, TC and TCDC up to 105%, 126%, 141% and 155% at concentrations of 0.1, 1.0, 1.5 and 3.0 mM, respectively. There were no consistent differences in the potency of the conjugated and unconjugated bile acids. The two variables were significantly positive correlated for the rat colonic brush-border membranes. These data demonstrate direct effects of bile acids on rat colonic brush-border membrane fluidity and proton permeability that are likely to be early events in bile acid-induced mucosal damage.

Animals↗
PubMed1995

Homozygous deletions at 8p22 and 8p21 in prostate cancer implicate these regions as the sites for candidate tumor suppressor genes.

Frequent loss of an allele at specific chromosomal regions implicates these regions as sites of tumor suppressor genes (TSG) that become inactivated during tumor progression. We have studied chromosome 8p allele losses in 32 primary human prostate carcinomas with 16 polymorphic microsatellite sequences. Overall, 22 of 32 (69%) informative specimens showed loss of allele in at least one locus. The most frequent losses of heterozygosity (LOH) occurred at the LPL locus (46%) on chromosome 8p22 and at the D8S360 (45%) and NEFL (43%) loci on chromosome 8p21. Homozygous deletions were detected at the LPL and NEFL loci at 8p22 and 8p21, respectively. The minimal region with frequent LOH and homozygous deletion, around the LPL locus, was restricted between the MSR locus and the D8S258 marker, separated by less than 9 cM. The second region was restricted between markers D8S1128 and D8S131 separated by 12 cM. The results suggest the existence of two chromosome 8p sites for candidate TSGs in prostate cancer.

Alleles↗
PubMed1995

The tissue-specific nuclear matrix protein, NMP-2, is a member of the AML/CBF/PEBP2/runt domain transcription factor family: interactions with the osteocalcin gene promoter.

The nuclear matrix protein, NMP-2, was originally identified as an osteoblast-specific DNA-binding complex localized exclusively to the nuclear matrix. NMP-2 was shown to recognize two binding sites, site A (nt-605 to -599) and site B (nt -441 to -435), in the rat bone-specific osteocalcin gene promoter. This study shows that the NMP-2 binding sites A and B as well as a third NMP-2 binding site (nt -135 to -130) constitute a consensus sequence, ATGCTGGT, and represent an AML-1 recognition motif. AML-1 is a member of the AML transcription factor family which is associated with acute myelogenous leukemia and binds to the sequence TGCTGGT via its DNA-binding runt domain. Electrophoretic mobility shift assays reveal that a component of NMP-2 is a member of the AML/PEBP2/runt domain transcription factor family based on cross-competition with AML-1 consensus oligonucleotide. Limited immunoreactivity of NMP-2 with a polyclonal N-terminal AML-1 antibody and inability of the AML-1 partner protein CBF-beta to form complexes with NMP-2 indicate that NMP-2 is not identical to AML-1 but represents a variant AML/PEBP2/runt domain protein. Western and Northern blots reveal the presence of multiple AML-related proteins and AML-1 transcripts in several osseous cell lines. Furthermore, our results indicate that AML family members may selectively partition between nuclear matrix and nonmatrix compartments. Because proteins that contain a runt domain are implicated in tissue-specific transcriptional regulation, our results support the concept that the nuclear matrix mediates osteoblast-specific expression of the osteocalcin gene.

Animals↗
PubMed1995

Stimulation of the human cytomegalovirus IE enhancer/promoter in HL-60 cells by TNFalpha is mediated via induction of NF-kappaB.

TNFalpha enhances the basal activity of the major Immediate Early (IE) enhancer/promoter of human cytomegalovirus (HCMV) in the immature premonocytic HL-60 cell line. The stimulatory effect of TNFalpha is mediated by induction of the transcription factor NF-kappaB, which specifically binds to the 18-bp repetitive sequence motif of the enhancer region. Complex formation could be competed by oligonucleotides representing the 18-bp sequence motif or the prototype NF-kappaB sequence of the immunoglobulin kappa gene. In gel mobility shift assays antisera specific to NF-kappaB p50 and p65 subunits were shown to react with the DNA-protein complex. Addition of the antioxidant PDTC blocked TNFalpha-mediated stimulation in a dose dependent manner. Electrophoretic mobility shift assays indicated that PDTC prevents NF-kappaB induction. Furthermore, it is suggested that protein kinases like PK-C are involved in the TNFalpha signal transduction pathway which leads to the activation of NF-kappaB and its binding to the HCMV IE enhancer in HL-60 cells. Our data are consistent with a role of TNFalpha in reactivation of latent HCMV infection in premonocytic cells.

Antigens, Viral↗
PubMed1995

Altered peptide ligands can control CD4 T lymphocyte differentiation in vivo.

Antigen priming of naive CD4 T cells can generate effector CD4 T cells that produce interleukin 4 (T helper [Th]2-like) or interferon-gamma (Th1-like). Using a system in which priming leads to responses dominated by one or the other of these cell types, we show that varying either the antigenic peptide or the major histocompatibility complex class II molecule can determine whether Th1-like or Th2-like responses are obtained. Our results show that peptide/major histocompatibility complex class II complexes that interact strongly with the T cell receptor favor generation of Th1-like cells, while those that bind weakly favor priming of Th2-like T cells. Thus, signals from the T cell receptor can influence the differentiation of CD4 T cells into specific types of effector cells.

Animals↗
PubMed1995

High-performance liquid chromatographic determination of nicotinic acid and nicotinamide in biological samples applying post-column derivatization resulting in bathmochrome absorption shifts.

An ion-pair reversed-phase high-performance liquid chromatographic procedure for the rapid separation and sensitive quantitation of nicotinic acid (NA) and nicotinamide (NAM) in biological samples was developed. The vitamers were separated within 10 min on an octadecylsilica column applying a linear gradient of tetrabutylammonium phosphate and methanol. NA and NAM were converted to highly absorbing derivatives by a modified König's reaction using a double post-column derivatization arrangement consisting of two pumps and two knitted tubular reactors. The proposed method is highly sensitive and specific and applicable to biological materials as was shown by the analysis of rat intestinal tissue.

Animals↗
PubMed1995

EGF stimulates polyamine uptake in Caco-2 cells.

We investigated the effects of epidermal growth factor (EGF) on polyamine uptake in Caco-2 cell monolayers. Cells were grown until confluence (day 7) or until differentiation (day 14). Polyamine uptake into Caco-2 cells was stimulated by EGF in a dose-dependent manner. Both basal and EGF-stimulated uptake rates were higher in 7- than in 14-day-old Caco-2 cells. Stimulation with EGF resulted in a significant increase in Vmax and an increased affinity for putrescine and spermine. Polyamine uptake was not inhibited when protein synthesis was blocked by cycloheximide, implying that no additional protein synthesis occured for stimulatory effect of EGF on polyamine uptake. The tyrosine kinase inhibitor, genistein, completely inhibited EGF-stimulated polyamine uptake, indicating that tyrosine phosphorylation plays a role in EGF-stimulated polyamine uptake in Caco-2 cells. The effect of EGF on polyamine uptake into Caco-2 cells, therefore, could be due to translocation of intracellular proteins which were not previously incorporated into the membrane, or direct alteration of polyamine transporter.

Adenocarcinoma↗
PubMed1995

Sequence-specific DNA binding activities of nuclear matrix proteins of mammalian lens epithelial cells.

This study examines matrix and nonmatrix nuclear proteins of the rabbit lens epithelial cells. The nuclear matrix proteins were isolated by modified Penman technique, which requires presence of detergents and nucleases, whereas nonmatrix nuclear proteins were obtained by high salt extraction. The data from these experiments revealed presence of DNA binding activities for SP-1 and OCT-1 proteins in both matrix and non-matrix compartments of rabbit lens epithelial cells. Comparison of the relative abundance of SP-1 and OCT-1 binding activities in nuclear matrix and nonmatrix fractions suggest the distribution between these two compartments is cell type specific and possibly related to the control of cell growth.

Animals↗
PubMed1995

Selective expression of fos- and jun-related genes during osteoblast proliferation and differentiation.

Developmental studies of oncogene expression and transgenic animal studies implicate c-fos and other fos and jun family members in the regulation of bone tissue formation. Therefore, to initiate experimental examination of the hypothesis that expression of fos- and jun-related genes is functionally coupled to modulation of gene expression which supports bone development, we determined levels of expression of the principle fos and jun family members during progressive differentiation of normal rat calvaria-derived osteoblasts within two contexts. First, cellular mRNA levels were quantitated under conditions where expression of serum-induced early response genes had returned to basal levels. Our findings demonstrate high levels of c-fos, c-jun, and jun B mRNA transcripts during the proliferative period of osteoblast development, while expression of fra-1 and fra-2 is enhanced during the differentiation period. jun D is constitutively expressed during the time course exhibiting only a 30% decline in levels postproliferatively, and fos B mRNA is undetectable by Northern blot analyses. Late in the developmental sequence, apoptosis is evident. At this time, fra-1 expression is completely downregulated, while c-fos, fra-2, c-jun, jun B, and jun D show a dramatic enhancement in expression. Second, we addressed differential expression of fos and jun family members in relation to serum responsiveness as a function of stages of phenotypic development. Proliferating cells exhibit a prolonged induction of fos and jun family members in response to serum. While in differentiated cells, which are refractory to growth stimulus even when exposed to fresh serum every 2 days, a spike in fos and jun expression is observed. Thus, our data demonstrate significant differences in basal and serum responsiveness of fos and jun family members over the course of osteoblast differentiation. These findings are consistent with multiple lines of evidence linking activity of these early response genes to regulation of cell growth and development of the bone tissue phenotype.

Animals↗
PubMed1995

The spatial distribution of Borrelia burgdorferi-infected Ixodes ricinus in the Connemara region of County Galway, Ireland.

Studies were carried out in the Connemara area of County Galway in the west of Ireland in order to determine the abundance and distribution of the tick, Ixodes ricinus and the prevalence of its infection with Borrelia burgdorferi. The tick was very abundant locally, in particular when associated with cattle, sheep and enclosed red deer. Large numbers of ticks not only occurred on the pastures, but also on adjacent roadside verges. No infections with B. burgdorferi could be demonstrated when nymphal ticks were sampled from central areas of the pastures, suggesting that livestock and red deer are probably not significant reservoirs of the spirochaete. Small numbers of infected nymphal and adult ticks were associated with hedges, dry stone walls, the margins of woodland adjoining infested pastures and in woodland from which livestock were excluded. Woodmice (Apodemus sylvaticus) were most numerous in such habitats and the majority were infected with B. burgdorferi.

Animals↗