A possible acetaldehyde-mediated cardioprotective mechanism.
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Acetaldehyde↗
Biomedical subjects
J D Pearson
Publications and source records attributed to J D Pearson.
Effects of protein tyrosine kinase inhibitors on cytokine-induced adhesion molecule expression by human umbilical vein endothelial cells.
1. Endothelial cells can be stimulated by the pro-inflammatory cytokines interleukin (IL)-1 alpha and tumour necrosis factor (TNF) alpha to express the leukocyte adhesion molecules E-selectin, vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1 but the intracellular signalling mechanisms leading to this expression are incompletely understood. We have investigated the role of protein tyrosine kinases (PTK) in adhesion molecule expression by cytokine-activated human umbilical vein endothelial cells (HUVEC) using the PTK inhibitors genistein and herbimycin A, and the protein tyrosine phosphatase (PTP) inhibitor sodium orthovanadate. 2. Maximal E-selectin expression induced by incubation of HUVEC for 4 h with IL-1 alpha (100 u ml-1) and TNF alpha (100 u ml-1) was dose-dependently inhibited by genistein and herbimycin A. Although similar effects were seen on phorbol 12-myristate, 13-acetate (PMA)-induced expression, this was not due to inhibition of protein kinase C (PKC) activity as the selective inhibitors of PKC, bisindolylmaleimide (BIM), Ro31-7549 or Ro31-8220 did not affect IL-1 alpha- or TNF alpha-induced E-selectin expression at concentrations which maximally inhibited PMA-induced expression. 3. Genistein inhibited VCAM-1 expression induced by incubation of HUVEC for 24 h with TNF alpha or IL-1 alpha whereas it did not affect ICAM-1 expression induced by 24 h incubation with either of these cytokines. Herbimycin A inhibited both VCAM-1 and ICAM-1 expression induced by TNF alpha. 4. Basal expression of E-selectin, VCAM-1 and ICAM-1 was dose-dependently enhanced by sodium orthovanadate. In contrast, vanadate differentially affected TNF alpha-induced expression of these molecules with maximal E-selectin and ICAM-1 expression being slightly enhanced and VCAM-1 expression dose-dependently reduced. 5. We also studied the effects of PTK and PTP inhibitors on adhesion of the human pre-myeloid cell line U937 to TNF alpha-stimulated HUVEC. Adhesion of U937 cells to HUVEC pretreated for 4 or 24 h with TNF alpha was dose-dependently inhibited by genistein and herbimycin A but unaffected by daidzein. Adhesion of U937 cells after 4 h was partially inhibited by blocking antibodies against both E-selectin and VCAM-1 but after 24 h was only inhibited by anti-VCAM-1. 6. Sodium orthovanadate had no effect on TNF alpha-induced U937 adhesion but dose-dependently enhanced adhesion to unstimulated HUVEC. Vanadate-induced adhesion was inhibited by an antibody against VCAM-1. 7. These results demonstrate that PTK-mediated phosphorylation events are important for the regulation of adhesion molecule expression by human endothelial cells, and additionally show that PTK inhibitors differentially affect upregulation of different adhesion molecules, implicating divergent regulatory pathways for cytokine-induced adhesion molecule expression.
Cell Adhesion Molecules↗
Age- and gender-specific reference ranges for hearing level and longitudinal changes in hearing level.
This paper presents age-specific reference ranges for hearing level and change in hearing level for men and women at 500, 1000, 2000, and 4000 Hz. The percentiles are constructed from data obtained from persons in the Baltimore Longitudinal Study of Aging who were rigorously screened for otological disorders and evidence of noise-induced hearing loss. The resulting percentile curves represent norms for changes in hearing level in the absence of any known otologic disease. These percentile curves provide a reference for detecting when a person deviates from a normal pattern of change, thus helping in diagnosing problems with hearing or in monitoring hearing in occupational settings. The smoothed means and standard deviations of the hearing levels were used to construct the longitudinal percentiles. The percentiles for cross-sectional change were constructed using the skew normal distribution to allow for the percentiles to be asymmetric on either side of the median level. These percentiles are the first reference curves that (1) provide standards for hearing level changes over periods of up to 15 years, (2) account for age differences in the distribution of hearing levels, and (3) are based on data from persons who have been systematically screened for otological disorders and evidence of noise-induced hearing loss.
Adult↗
Protein tyrosine kinase inhibitors act downstream of IL-1 alpha and LPS stimulated MAP-kinase phosphorylation to inhibit expression of E-selectin on human umbilical vein endothelial cells.
HUVEC exposed to IL-1 alpha, TNF alpha or LPS showed a time dependent increase in E-selectin expression which was maximal at between 4-6h after stimulation. Stimulation of HUVEC with IL-1 alpha, TNF alpha or LPS for between 2 and 6h followed by removal or neutralisation of IL-1 alpha, TNF alpha or LPS and incubation in new media up to 6h resulted in identical levels of E-selectin expression at 6h, as cells which had been continuously stimulated for 6h with IL-1 alpha, TNF alpha or LPS. These studies demonstrated that HUVEC were committed to the induction of E-selectin following a 2 hr incubation with either IL-1 alpha, TNF alpha or LPS. The protein tyrosine kinase (PTK) inhibitors ST271, ST638 or genistein (0-100M) were ineffective in reducing cytokine or LPS stimulated E-selectin expression during a 2h cytokine or LPS stimulation of cells, in which inhibitors were either coincubated with cytokine/LPS or previously preincubated with the PTK inhibitors. However when PTK inhibitors were present during both agonist activation (2h) and subsequent expression of E-selectin after removal of agonist (4h) the PTK inhibitors resulted in a dose dependent reduction in both IL-1 alpha and LPS stimulated E-selectin expression (IC50 = 50M). Moreover when PTK inhibitors were only incubated with cells for the 4h after cytokine or LPS activation of cells, PTK inhibitors resulted in a more effective dose dependent reduction in IL-1 alpha or LPS stimulated E-selectin expression (IC50 = 10M). Determination of total and surface expressed E-selectin showed that the reduction in E-selectin expression represented a reduction in E-selectin protein and analysis of E-selectin mRNA by RT-PCR demonstrated that inhibition of E-selectin protein synthesis reflected reduced E-selectin mRNA. Other cytokine or LPS signalling pathways such as the activation of MAP-kinase (ERK-2) was unaffected by pre and coincubation with the PTK inhibitors. These studies suggest that HUVEC can become committed to the induction of E-selectin after removal of the stimulus and that protein tyrosine kinase inhibitors do not effect initial (5-30 min) cytokine or LPS signals which result in E-selectin expression but can inhibit the expression of cytokine/LPS induced E-selectin expression at a step distal to MAP-kinase activation.
Calcium-Calmodulin-Dependent Protein Kinases↗
Scleroderma fibroblast phenotype is modulated by endothelial cell co-culture.
OBJECTIVE: We established a co-culture system to investigate endothelial cell-fibroblast interaction in scleroderma (systemic sclerosis, SSc). Such a system allows reciprocal interaction between these cells. The pattern of phenotypic modulation for normal and SSc fibroblasts in co-culture was compared. METHODS: A virally transformed human umbilical vein endothelial cell (HUVEC) derived cell line (1E-7) was cultured on nitrocellulose membrane inserts above dermal fibroblast monolayers. The effect of co-culture on fibroblast number, [3H]-thymidine ([3H]-TdR) incorporation, and collagen (type I) production were compared for 10 SSc and 5 control cell lines. Co-culture with the epithelial lines A549 and A431, and nontransformed HUVEC, was also investigated. RESULTS: We observed a statistically significant increase in cell number and a reduction in collagen production for SSc, but not control, fibroblasts co-cultured with endothelial cells. This co-culture also promoted [3H]-TdR incorporation in both SSc and control fibroblasts. While epithelial cell lines did not influence fibroblast cell number, collagen production by SSc fibroblasts was diminished by A549. CONCLUSIONS: Endothelial cell derived soluble factors modulated fibroblast properties in co-culture, and the different response of SSc compared with normal fibroblasts provides further evidence for a link between endothelial and fibroblast dysfunction in this disease. However, similar effects on SSc fibroblast collagen production were also observed for some epithelial cells, suggesting that modulation of fibroblast properties is not restricted to cells of endothelial origin.
Adult↗
Risk factors related to age-associated hearing loss in the speech frequencies.
This paper examines the relationship between several risk factors and the development of age-associated hearing loss in the speech frequencies. Hearing loss is defined as an average threshold level of 30 dB HL or greater at the frequencies of 0.5, 1, 2, and 3 kHz. Hearing thresholds from 0.5 to 8 kHz using a pulse-tone tracking procedure were collected on participants of the Baltimore Longitudinal study of Aging since 1965. A proportional hazards regression model was used to study the relationship between several risk factors that have previously been found to be associated with numerous health-related outcomes and the length of follow-up time until the occurrence of unilateral or bilateral hearing loss in a screened group of 531 men. Risk factors considered are age, blood pressure, and alcohol and cigarette consumption. After controlling for age, only systolic blood pressure showed a significant relationship with hearing loss in the speech frequencies (p < .05). Since blood pressure is a modifiable risk factor, these results suggest that preventing hypertension might contribute to an effective program for the prevention of apparent age-associated hearing loss.
Adult↗
Characterization of human IgG-binding xenoantigens expressed by porcine aortic endothelial cells.
Xenoreactive antibodies (XAb) play a major role in the rejection of xenografts. In this study, human IgG XAb that bind to xenoantigens expressed by porcine aortic endothelial cells (PAEC) were characterized, together with their corresponding xenoantigens. Using an ELISA with both fixed and unfixed confluent monolayers of PAEC, XAb of both IgG and IgM classes in pooled and individual normal human serum were identified. The binding of these IgG XAb to the endothelium is mediated by F(ab')2 and the only detectable subclasses that bind to the endothelium are IgG1 and IgG2. On the basis of direct binding experiments, inhibition and antibody adsorption studies, and enzymatic digestions, it is shown that only a minor component of the XAb binding is directed against galactose in an alpha 1,3 linkage with galactose on PAEC surfaces. There is some cross-reactivity with antigens expressed on porcine lymphocytes, but not porcine red blood cells. Histological examination of sections of porcine aortae, snap-frozen and stained using immunoperoxidase techniques, confirmed interaction with the vascular endothelium. Labeling of the PAEC with 125I, followed by cell lysis and immunoprecipitation under reducing conditions, showed binding of IgG XAb to several components on the endothelial cell surface, the most prominent of which have apparent molecular masses of 75 kDa, 110 kDa, 180 kDa, and 210 kDa. The 110-kDa component and the 180-kDa component were sensitive to digestion with endoglycosidase F, which suggests the participation of N-linked carbohydrate structures. These studies demonstrate that human IgG XAb recognize multiple determinants expressed by PAEC, a minor population of which contain alpha 1,3-linked galactose residues. Cross-reactive determinants are expressed on porcine lymphocytes but not porcine red blood cells.
Animals↗
Induction of the antioxidant stress proteins heme oxygenase-1 and MSP23 by stress agents and oxidised LDL in cultured vascular smooth muscle cells.
Enhanced expression of the antioxidant stress proteins heme oxygenase-1 (HO-1) and macrophage stress protein (MSP23) by oxidative stress agents and oxidatively modified low density lipoproteins (LDL) was investigated in cultured porcine aortic smooth muscle cells. Treatment of smooth muscle cells with glucose oxidase, CdCl2 or diethylmaleate resulted in a time-dependent (6-48 h) induction of HO-1 and MSP23 expression. Exposure of cells to 100 micrograms protein/ml highly oxidised LDL increased the expression of HO-1 and MSP23 within 24 h, and the induction was dependent on the degree of LDL oxidation. The induction of HO-1 and MSP23 may thus play an important cytoprotective role against oxidative stress in atherogenesis.
Animals↗
Differential regulation of von Willebrand factor exocytosis and prostacyclin synthesis in electropermeabilized endothelial cell monolayers.
We have developed a system to permeabilize human umbilical vein endothelial cells in monolayer culture by application of a high-voltage electric field. The permeabilized preparation allows access of small molecules (M(r) < 1000) without loss of large cytosolic proteins. Electropermeabilized cells exocytose highly multimeric von Willebrand factor from secretory granules in response to added Ca2+ (EC50 = 0.8 +/- 0.02 microM), with levels comparable with those observed on stimulation of intact endothelial cells by physiological agonists. MgATP2- potentiates Ca(2+)-driven von Willebrand factor secretion. Other nucleoside triphosphates, but not non-hydrolysable analogues, can replace ATP. Electropermeabilized cells also synthesize and release prostacyclin in response to added Ca2+ (EC50 = 0.3 +/- 0.08 microM), but nucleoside triphosphates markedly inhibit, whereas nonhydrolysable GTP analogues increase, Ca(2+)-driven prostacyclin synthesis. We conclude that elevation of the intracellular [Ca2+] is sufficient to cause efficient exocytosis of von Willebrand factor from permeabilized cells, despite evidence that additional second messengers are needed in intact cells. We find no evidence in endothelial cells for a guanine nucleotide-binding protein promoting exocytosis, although one is clearly involved in stimulating Ca(2+)-driven prostacyclin synthesis.
Calcium↗
Kinetics of extracellular ATP hydrolysis by microvascular endothelial cells from rat heart.
We have characterized the ectonucleotidases that catalyse the reaction sequence ATP-->ADP-->AMP-->adenosine on microvascular endothelial cells cultured from the rat heart. Computer simulation and data fitting of progress of reaction curves showed that depletion of substrate at the cell surface dominates the regulation of the rate of hydrolysis of ATP when it is presented to the cells. Preferential delivery of AMP by ADPase to 5'-nucleotidase makes a significant contribution to the regulation of adenosine production from ATP or ADP. By contrast, we found no evidence for the preferential delivery of ADP from ATPase to ADPase. Feed-forward inhibition of AMP hydrolysis by ADP and/or ATP also modulated the rate of adenosine production. The properties of the ectonucleotidases on rat heart microvascular cells are such that adenosine is produced at a steady rate over a wide range of ATP concentrations.
Adenosine↗
Cloning and base sequence analysis of a cDNA encoding mouse lung thioether S-methyltransferase.
Thioether S-methyltransferase catalyzes transfer of the methyl group from S-adenosylmethionine to X in compounds of the structure R-X-R', where X may be sulfur, selenium, or tellurium, and R and R' may be various organic groups. To obtain a cDNA clone of thioether S-methyltransferase, a mouse lung cDNA library in lambda gt11 was screened with a 99 base-pair probe obtained by performing the polymerase chain reaction on oligo(dT) primed, reverse transcribed, mouse lung RNA using two degenerate primers designed from partial amino-acid sequences of the enzyme. The entire coding and 3'-untranslated regions were obtained and sequenced. The predicted protein contains 264 amino-acid residues and has a calculated M(r) of 29,460. The amino-acid sequence of thioether S-methyltransferase contains three motifs characteristic of many methyltransferases and has a high level of identity with the amino-acid sequences of nicotinamide N-methyltransferase and phenylethanolamine N-methyltransferase. However, in spite of the fact that they are both mammalian cytosolic sulfur methyltransferases, the sequences of thioether S-methyltransferase and thiopurine S-methyltransferase share little identity.
Amino Acid Sequence↗
Longitudinal evaluation of serum androgen levels in men with and without prostate cancer.
Androgens are thought to play a role in the pathogenesis of prostate cancer. We evaluated androgen levels in 3 age-matched groups of men who were part of the Baltimore Longitudinal Study of Aging: 1) 16 men with no prostatic disease by urologic history and exam (control group); 2) 20 men with a histologic diagnosis of benign prostatic hyperplasia (BPH) who had undergone simple prostatectomy; and 3) 20 men with a histologic diagnosis of prostate cancer (16 with local/regional cancer, and 4 with metastatic cancer). Luteinizing hormone (LH), total testosterone (T), and free T were measured on stored AM sera by radioimmunoassay (RIA). Free T was also calculated from the measured concentrations of total T and sex hormone binding globulin (SHBG). The median number of repeated sex steroid measurements ranged from 6-9 over a period from 7-25 years prior to the diagnosis of prostate disease. There were no significant differences in age-adjusted LH, total T, SHBG, or calculated free T levels among the groups at 0-5, 5-10, and 10-15 years before diagnosis. These data suggest that there are no measurable differences in serum testosterone levels among men who are destined to develop prostate cancer and those without the disease.
Age Factors↗
Prostate-specific antigen variability in men without prostate cancer: effect of sampling interval on prostate-specific antigen velocity.
OBJECTIVES: To evaluate short-term and long-term variability between prostate-specific antigen (PSA) measurements to determine the most appropriate PSA sampling interval and rate of PSA change (PSA velocity) to distinguish between men with and without prostate cancer. METHODS: Retrospective study of PSA variability and PSA velocity in three groups of men without a diagnosis of prostate cancer and PSA levels less than 10 ng/mL: 56 men with a histologic diagnosis of benign prostatic hyperplasia (BPH; histologic BPH group) and 527 men with no history of cancer (noncancer group) who were part of the Baltimore Longitudinal Study of Aging and had PSA sampled at 2-year intervals (long-term), and 223 men with a clinical diagnosis of BPH (clinical BPH group) who had PSA sampled at 3-month intervals (short-term). PSA variability (deviation between consecutive measurements) and PSA velocity based on both two consecutive measurements and three consecutive measurements (average velocity) were calculated for each study group. RESULTS: PSA velocity is the deviation in PSA measurements relative to the elapsed time between the measurements. Because the variability in PSA between measurements was similar for the groups, the major factors that influenced PSA velocity were the sampling interval between PSA measurements, and to a lesser extent, the number of repeat PSA measurements. The 99th percentile for PSA velocity was 0.7 (histologic BPH group) and 0.75 ng/mL per year for the noncancer group when three measurements with a 24-month PSA sampling interval were used. However, the 99th percentile for PSA velocity was 5.8 and 2.4 ng/mL per year when three measurements with 3-month and 6-month PSA sampling intervals were used. Using three measurements, the percentage of subjects with a PSA velocity more than 0.75 ng/mL per year was 1% for the groups with a 24-month PSA sampling interval and 28% and 17% for 3-month and 6-month PSA sampling intervals, respectively. The 99th percentile for PSA velocity and the percentage of subjects with a PSA velocity more than 0.75 ng/mL per year was higher using two measurements compared to three measurements regardless of PSA sampling interval. CONCLUSIONS: PSA velocity is inversely related to the interval between PSA measurements. A PSA velocity more than 0.75 ng/mL per year is useful in distinguishing between men with and without prostate cancer when: (1) velocity is based on three consecutive measurements; and (2) PSA is sampled long-term (2 years) but not short-term (3 to 6 months).
Aged↗
Relationship between changes in prostate-specific antigen and the percent of prostatic epithelium in men with benign prostatic hyperplasia.
OBJECTIVES: Pretreatment knowledge of prostate gland histology would allow a more scientifically based selection of medical therapy for men with benign prostatic hyperplasia (BPH) and may increase the effectiveness of the pharmacologic agents available. Changes in prostate-specific antigen (PSA), or PSA velocity, may reflect prostatic epithelial growth in BPH. Our objective was to determine if PSA velocity prior to diagnosis correlated with the relative amount of epithelium in BPH tissue. METHODS: We evaluated 39 men with BPH who had serial PSA determinations (mean, 5.4) on frozen sera from 2.3 to 25.1 years before diagnosis, and archival material from simple prostatectomy available for pathologic evaluation. We used an immunoenzymatic staining technique for PSA to bind prostatic epithelium selectively so that color differences in the stained tissue sections could be used to quantify stroma, epithelium, and glandular lumina. RESULTS: The average percentage of epithelium (%E) was 12.4 and the average stroma-epithelial ratio (SER) was 6.6. The correlation of PSA velocity for the three visits nearest to prostatectomy (n = 32) versus %E and SER was significant (P = 0.003 for both). The PSA value nearest to prostatectomy (n = 39) was directly correlated with %E and SER (P = 0.0001 and P = 0.001, respectively). CONCLUSIONS: These data suggest that PSA and PSA velocity are directly related to the histologic makeup of the prostate in men with BPH. Thus, pretreatment evaluation of PSA could be useful as part of an evaluation to direct BPH therapy.
Aged↗
Cytokine-induced E-selectin expression by human umbilical vein endothelial cells (HUVEC). A role for protein tyrosine kinases?
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Benzoquinones↗
Thrombin and histamine phosphorylate the 42 kDa mitogen-activated protein kinase in HUVEC.
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Antibodies↗
Phosphatase inhibitors potentiate the release of vasoactive mediators from human endothelium.
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Cells, Cultured↗
Endothelium-derived haemostatic factors and the antiphospholipid syndrome.
The cause of thrombosis in the antiphospholipid syndrome (APS) is unknown. There have been reports of abnormalities in the antigenic levels or activity of endothelium-derived haemostatic factors, such as tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1); however the data from these studies are conflicting. We studied plasma from nine patients with APS; seven of them had a history of thrombosis, and three had systemic lupus erythematosus (SLE). We also studied nine matched control patients who had SLE without APS, and 14 healthy individuals. We measured t-PA, von Willebrand factor (vWF), anticardiolipin antibody (ACA) and anti-endothelial cell antibody (AECA) levels by enzyme-linked immunoassay (ELISA), PAI-1 activity by a parabolic-rate chromogenic assay, and lupus anticoagulant (LA) activity by a standard mixing test. For t-PA and PAI-1, measurements were made on morning and evening plasma samples. The two groups of patients did not differ significantly with respect to age, sex, plasma lipids or anti-inflammatory drugs. Most APS patients (7/9) but none of the controls were taking warfarin. Between the APS and the control patients no significant differences were detected in t-PA, PAI-1, vWF or AECA levels. When APS patients were considered alone, vWF levels correlated positively with IgG ACA levels (r = 0.81, P < 0.01) and negatively with platelet count (r = -0.68, P < 0.05). There was no correlation between levels of ACA or LA activity and t-PA, PAI-1 or AECA. Compared with healthy volunteers, the diurnal variation of t-PA and PAI-1 was blunted in the two patient groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗