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Biomedical subjects

W Huang

Publications and source records attributed to W Huang.

At least 523 records · Page 29Linked to original sources
PubMed1995

RT/PCR detection of SIL-TAL-1 fusion mRNA in Chinese T-cell acute lymphoblastic leukemia (T-ALL).

The TAL-1 gene is located on chromosome 1p32. In about 20% of T-cell acute lymphoblastic leukemias (T-ALL), this gene is disrupted in its 5' portion by a site-specific 100-kg deletion and is fused with the 5' part of the SIL gene, to form SIL-TAL-1 chimeric gene. In this study, we established a "nested" retrotranscriptase/polymerase chain reaction (RT/PCR) technique which allows detection of the SIL-TAL-1 transcriptional expression. A chimeric mRNA was observed in four of 17 T-ALL cases and has been shown to result from the fusion between the exon 1 of SIL and exon 3 of TAL. A sensitivity test showed that this RT/PCR procedure could detect one leukemic cell among 10(6) normal cells. A positive RT/PCR result was obtained in two cases during clinical remission, suggesting the presence of minimal residual disease (MRD). One patient developed clinical relapse 3 months after PCR positivity. Moreover, analysis of the Tald rearrangement by DNA-based PCR in four patients with SIL-TAL-1 fusion revealed the type A (Tald1) rearrangement in all cases. Sequence analysis demonstrated the presence of N region and non-random "P" nucleotide, as well as base deletions at the genomic SIL-TAL-1 joining site. These data indicate that detection of TAL-1 gene abnormality is important for diagnosis and monitoring of MRD in a subset of T-ALL.

Adolescent↗
PubMed1995

Selenoprotein P in serum as a biochemical marker of selenium status.

Some characteristics of a radioimmunoassay of selenoprotein P (a major selenoprotein in human serum) are described. Polyclonal antibodies generated in rabbits were used and goat anti-rabbit-IgG antiserum was used as a second antibody. Depending on the concentration of selenoprotein P, 1-10 microliters of human serum were used in the assay. The relative standard deviation for the concentration of selenoprotein P was 6.3% between assays and 7.7% within assays. Different animal sera gave no significant interference, indicating that the antibodies did not react with non-human analogues of selenoprotein P. No indication of cross-reactivity could be found concerning extracellular glutathione peroxidase (another selenoprotein in serum). Addition of increasing amounts of normal human serum and partially purified selenoprotein P to the radioimmunoassay resulted in parallel curves. Incubation at 4 degrees C gave somewhat higher binding of labelled selenoprotein P than incubation at room temperature. The epitope, recognized by the antibodies, was apparently stable after storage of serum (in the frozen state for years, and in the cold for months). No significant amount of selenoprotein P could be demonstrated in red blood cells, and analysis of haemolysed whole blood gave expected data. Investigations of selenium status in different study groups indicated that in most cases the concentration of selenoprotein P in serum was positively correlated to that of glutathione peroxidase and serum selenium. In an intervention study, where subjects decreased their selenium intake to 50%, the serum levels of glutathione peroxidase and selenium decreased, but no significant decrease of selenoprotein P could be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗
PubMed1995

Selenoprotein P and glutathione peroxidase (EC 1.11.1.9) in plasma as indices of selenium status in relation to the intake of fish.

In Sweden fish is considered to be an important source of dietary Se. Therefore Se status was assessed in forty-one middle-aged men with widely varying fish consumption. Glutathione peroxidase (EC 1.11.1.9) and selenoprotein P in plasma were measured by radioimmunoassay. Plasma Se among the men increased slightly with increasing consumption of fish, but no such increases in the concentrations of glutathione peroxidase and selenoprotein P in plasma were observed. Moreover, no correlation was found between plasma Se and glutathione peroxidase or selenoprotein P. Instead, glutathione peroxidase was significantly correlated with selenoprotein P (r 0.73, P < 0.001), indicating that both glutathione peroxidase and selenoprotein P were functional indicators of Se status in this group. The proportion of plasma Se located in glutathione peroxidase decreased with increasing plasma Se. The results suggest that the Se consumed from fish had no apparent effect on the amount of Se incorporated into the functional selenoproteins of plasma. It is concluded that in some cases selenoproteins may be better biological markers of Se status than the total concentration of Se.

Animals↗
PubMed1995

Effect of adenoviral vector infection on cell proliferation in cultured primary human airway epithelial cells.

Although recombinant adenoviruses are used as vectors for delivering therapeutic genes to the airways of cystic fibrosis (CF) patients, the effects of these vectors on the kinetics of airway epithelial cell growth have not been investigated. We tested whether E1, E3-deleted Ad vectors (Ad5-CMV-lacZ) affect the kinetics of cell proliferation of human airway epithelial cells in primary culture. There was a dose-dependent relationship between the vector multiplicity of infection (moi) and the efficiency of Ad-mediated lacZ gene transfer. Growth curves of cells exposed to vector were shifted to the right as compared to vehicle in a dose-dependent manner. The vector-induced slowing of cell proliferation resulted from both (i) increased apoptotic cell death and (ii) lower recruitment into S phase. UV inactivation of the vector genes abolished the effects on cell proliferation. These data demonstrate that as the moi of vectors is increased to achieve effective gene transfer, apoptosis and slowing of the cell cycle of infected cells increases concomitantly. The identification and inactivation of these vector effects on human airway cells may be important for reducing the toxicity of adenovirus vectors for gene therapy of CF airways.

Adenoviruses, Human↗
PubMed1995

Biochemical and biological analysis of Mek1 phosphorylation site mutants.

Recently, we described the constitutive activation of Mek1 by mutation of its two serine phosphorylation sites. We have now characterized the biochemical properties of these Mek1 mutants and performed microinjection experiments to investigate the effect of an activated Mek on oocyte maturation. Single acidic substitution of either serine 218 or 222 activated Mek1 by 10-50 fold. The double acidic substitutions, [Asp218, Asp222] and [Asp218, Glu222], activated Mek1 over 6000-fold. The specific activity of the [Asp218, Asp222] and [Asp218, Glu222] Mek1 mutants, 29 nanomole phosphate per minute per milligram, is similar to that of wild-type Mek1 activated by Raf-1 in vitro. Although the mutants with double acidic substitutions could not be further activated by Raf-1, three of those with single acidic substitution were activated by Raf-1 to the specific activity of activated wild-type Mek1. Injection of the [Asp218, Asp222] Mek1 mutant into Xenopus oocytes activated both MAP kinase and histone H1 kinase and induced germinal vesicle breakdown, an effect that was only partially blocked by inhibition of protein synthesis. These data provide a measure of Mek's potential to influence cell functions and a quantitative basis to assess the biological effects of Mek1 mutants in a variety of circumstances.

Amino Acid Sequence↗
PubMed1995

Immunoassay detection of benzodiazepines and benzodiazepine metabolites in blood.

We evaluated the capability of commercially available benzodiazepine immunoassays from four vendors (Abuscreen radioimmunoassay [RIA-a] from Roche Diagnostic Systems and serum RIA-d from Diagnostic Products Corporation; X-systems serum and urine fluorescence polarization immunoassays [FPIA] from Abbott Laboratories; and EMIT TOX serum and EMIT urine enzyme immunoassays [EIA] from Syva) to detect 22 benzodiazepines and 16 benzodiazepine metabolites in blood samples. Drug-free bovine blood was fortified with the different compounds at concentrations relevant to blood analysis: 7, 30, and 70 ng/mL. One-milliliter samples were extracted with n-butyl chloride, dried, and reconstituted with 0.3 ml. of buffer. Results from the two urine-specific kits (EIA-u and FPIA-u) produced either equivalent or reduced cross-reactivity compared with their serum kit counterparts; these results are presented but not discussed further. Among the 38 compounds, the following were detected by all four assays at concentrations of 70 ng/mL or less: alprazolam, alpha-hydroxy-alprazolam, norclobazam, diazepam, estazolam, flunitrazepam, norflunitrazepam, miclazolam, 4-hydroxy-midazolam, nitrazepam, noradinazolam, oxazepam, prazepam, 3-hydroxy-prazepam, temazepam, and triazolam. 7-Amino-clonazepam, 7-acetamido-clonazepam, 3-hydroxy-7-acetamidoclonazepam, haloxazepam, loprazolam, 7-amino-nitrazepam, 7-acetamido-nitrazepam, and oxazolam were not detected by any of the assays at concentrations up to 70 ng/mL. A number of benzodiazepines or their metabolites were detectable by some but not all of the six assays: bromazepam, chlordiazepoxide, demoxepam, and 4-hydroxy-alprazolam (both RIAs and EIA); adinazolam (RIA-a, EIA, and FPIA); norchlordiazepoxide (both RIAs); clonazepam (RIA-a and EIA); bentazepam, clotiaze-pam, and mexazolam (EIA and FPIA); 7-amino-flunitrazepam and quazepam (EIA); and alpha-hydroxy-triazolam and medazepam (RIA-a).

Animals↗
PubMed1995

Anti-idiotypic antibody as potential serodiagnostic reagent for detection of bluetongue virus infection.

Polyclonal anti-idiotypic antibodies (anti-Ids) were generated by the sequential immunization of rabbits with three mouse monoclonal antibodies (MAb1s) specific for a major bluetongue virus (BTV) protein, VP7. The anti-Ids, designated RAb2s, recognized idiotopes which were located within or near the antigen-combining sites of the MAb1s and were associated with both heavy and light chains of MAb1s. RAb2s inhibited the MAb1s from binding to BTV antigens, and their interaction with MAb1s was inhibited by BTV antigens. By recognizing the common idiotopes, RAb2s detected anti-BTV antibodies from bovine antisera; their interaction was also partially inhibited by BTV antigens. These results indicated that RAb2s recognized the common idiotopes on anti-VP7 antibodies obtained from mice and cattle and that at least a portion of RAb2s were internal-image anti-Ids that functionally mimicked VP7. RAb2s may be used to substitute for the tissue culture-derived viral antigen in currently used serological assays for the detection of antibodies to BTV.

Animals↗
PubMed1995

A real-time, flat-panel, amorphous silicon, digital x-ray imager.

As part of the development necessary for implementing a fully digital radiology department, the authors have investigated thin-film photodiodes and transistors for use in new photoelectronic imaging devices. One such device, a large-area, flat-panel, amorphous silicon imaging array, has been developed and is currently being tested. The array has a format of 512 x 560 pixels, a pixel-to-pixel pitch of 450 microns, and an area of 230 x 252 mm2, making it the largest self-scanning, solid-state imaging array developed to date. The array is used in conjunction with an overlying x-ray converter. Although specifically designed for megavoltage imaging, the device can produce high-quality, low spatial resolution, diagnostic x-ray images. Qualitative comparisons of array images of anthropomorphic head, chest, and pelvic phantoms and a spatial resolution pattern suggest that much of the information content of the film images at low spatial resolution is present in the corresponding array images. Current trends in the development of large-area, flat-panel imaging technology hold the promise of higher resolution arrays in the near future.

Humans↗
PubMed1995

Natriuretic role of endogenous oxytocin in male rats infused with hypertonic NaCl.

The involvement of endogenous oxytocin (OT) in the renal natriuretic response to an intravenous load of hypertonic and isotonic saline was investigated in anesthetized male rats with use of a selective OT-receptor antagonist [Mpa1,D-Tyr(Et)2,Thr4,Orn8]-OT (OT-ant). NaCl was infused (0.05 mmol.min-1.kg body wt-1 iv for 120 min) as a hypernatremic (HNa) solution or as an isotonic solution producing volume expansion (VE). HNa markedly increased sodium excretion from 0.25 +/- 0.06 to 10.04 +/- 0.62 mumol/min, whereas VE yielded only a moderate increase from 0.25 +/- 0.04 to 1.64 +/- 0.15 mumol/min. The increase in potassium excretion and urine flow rate during HNa was similar to that during VE. There were no significant changes in mean arterial pressure in either case. Administration of OT-ant delayed the natriuresis induced by HNa and reduced it by 60% but did not affect that induced by VE. Plasma OT concentration was significantly increased from 10.2 +/- 1.7 to 18.8 +/- 1.8 pg/ml at the end of HNa stimulation. In conclusion, the natriuresis in response to the intravenous sodium load was much more pronounced when NaCl was administered as a hypertonic solution than as an infusion inducing isotonic VE. Direct evidence was produced to assert that endogenous OT and its receptors are highly involved in the natriuresis elicited by systemic hypernatremic stimulation.

Animals↗
PubMed1995

Addition of carbonic anhydrase augments extracellular pH buffering in rat cerebral cortex.

1. The ability of the extracellular space to buffer rapid alkaline shifts was studied in rat cortex in vitro and in vivo. Alkaline shifts were generated by iontophoresis of OH- or were evoked by pressure ejection of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). 2. In cortical slices, alkaline shifts induced by OH- were enhanced by the carbonic anhydrase (CA) inhibitor benzolamide (83 +/- 16%, mean +/- SE), and were decreased by superfusion of 10 mg/l CA (-59 +/- 4%). CA had no effect at 1 mg/l, and no additional effect at 100 mg/l. 3. In slices, and in vivo, alkaline shifts induced by AMPA were similarly enhanced by benzolamide and decreased by superfusion of CA. 4. These data indicate that extracellular CA activity is less than that required for maximum buffering. This suggests that equilibrium between CO2 and bicarbonate may not be attained during rapid extracellular pH shifts.

Aging↗
PubMed1995

Glucocorticoids inhibit D1B, but not D2, receptor-mediated effects on hypothalamic atrial natriuretic factor neurons.

Recent evidence suggests that ANF neurons of the hypothalamus are dopamine sensitive, and the catecholamine may exert a direct stimulatory or inhibitory effect on the neurons mediated through D1 or D2 receptors, respectively, in a manner related to the differential dopamine binding sensitivity of the two receptor subtypes. Employing well characterized ANF RIA and colorimetric Northern blot analysis with synthetic oligonucleotide probes complementary to pro-ANF messenger RNA (mRNA), we report here the effect of dexamethasone (DM), a potent synthetic glucocorticoid, on DA-stimulated ANF neurons in long term primary cultures of neonatal rat hypothalamic cells. Although DM alone did not affect basal secretion of immunoreactive ANF, it approximately halved immunoreactive ANF secretion induced by D1 agonist, SKF38393 (P < 0.01). The effect of DM was both time dependent and dose related, with an EC50 of 0.1 nM; it was blocked by 100 nM RU38486 (P < 0.05), a glucocorticoid receptor antagonist, but not by 100 nM RU28318, a mineralocorticoid receptor antagonist. In addition, the effect of DM was mimicked by corticosterone (EC50, 10 nM), but not deoxycorticosterone. The increased expression of pro-ANF mRNA signal induced by the D1 agonist in culture was suppressed by DM in a similar manner. In contrast, DM did not modulate ANF production and secretion induced by D2 agonist, quinpirole. Furthermore, reverse transcription-polymerase chain reaction demonstrated that D1B, but not D2, receptor mRNA expression was selectively suppressed by glucocorticoids. Thus, we conclude that in monolayer cultures of rat hypothalamic neurons, glucocorticoids differentially modulate dopamine receptor-induced responsiveness of ANF neurons by down-regulating D1B, but not D2, receptor-mediated changes. Hence, in severe stress, high levels of circulating glucocorticoids may negate the D1B-induced stimulatory response but allow dopamine to suppress the function of hypothalamic ANF neurons through D2 receptor activation.

Animals↗
PubMed1995

D1 receptors mediate dopamine stimulation of immunoreactive atrial natriuretic factor (ANF) release and pro-ANF messenger ribonucleic acid expression of rat hypothalamic neurons in culture.

Atrial natriuretic factor (ANF) and its smaller congeners are produced and released from rat brains to regulate the cardiovascular system, drinking behavior, and neurohormone release at the central level. In the hypothalamus, the adenylyl cyclase-cAMP system plays an important role in modulating the function of ANF neurons in the paraventricular nuclei and the periventricular regions that receive rich dopaminergic inputs. We report here a novel observation of a dopamine (DA) D1 agonist, SKF-38393, modulating immunoreactive (ir) ANF and pro-ANF messenger RNA (mRNA) expression in rat hypothalamic neurons. In long term primary cultures of neonatal rat hypothalamic cells, treatment with SKF-38393 increased irANF secretion in a time-related and dose-dependent manner, with an ED50 of approximately 10(-7) M and a concentration producing maximum effect of 10(-5) M. This stimulating effect of SKF-38393 was mimicked by 10(-5) M DA, a physiological ligand for D1 receptors. Furthermore, both of the stimulatory effects were abolished by SCH-23390, a D1 antagonist. These immunoassay findings were accompanied by corresponding changes in the abundance of pro-ANF mRNA in the cultures, as examined by colorimetric Northern blot analysis. By combining the techniques of in situ hybridization and immunocytochemistry, the mRNA of D1 receptor was colocalized in approximately 90% of the irANF-positive cells in the cultures. In addition, cholera toxin, an irreversible activator of adenylyl cyclases, markedly increased irANF secretion and cAMP production in a dose-dependent manner. This effect mimicked that of D1 agonist-stimulated ANF release, in that the latter also concurrently enhanced cAMP production in the hypothalamic cultures. Furthermore, the stimulatory effect of D1 agonist on irANF release was markedly suppressed by rp-cAMPS, a cAMP antagonist. We, thus, conclude that the release and gene expression of ANF in rat hypothalamic neurons are directly stimulated by DA acting through its D1 receptors on ANF neurons; this effect may operate at the genomic level and is mediated at least in part through activation of the cAMP-dependent kinase-A pathway.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1995

Nutritional assessment with bioelectrical impedance analysis in maintenance hemodialysis patients.

Protein energy malnutrition is common among persons with ESRD and contributes substantially to morbidity and mortality. The usual methods of nutritional assessment, such as anthropometry, can be misleading because of altered tissue hydration. Bioelectrical impedance analysis (BIA) has been recommended by some as a practical nutritional assessment tool but has not been validated in patients with ESRD. Thirty-three stable patients on maintenance hemodialysis were evaluated in an ambulatory clinical research center with simultaneous BIA, dual-energy x-ray absorptiometry, and deuterium oxide (D2O) and sodium bromide (NaBr) isotope dilution studies. Standard determinations of total body water (TBW) and body cell mass (BCM) were obtained and compared with values estimated by BIA. Two separate outpatient BIA measurements were also obtained approximately 2 wk before and after the clinical research center evaluation. BCM estimated by BIA was directly correlated (r = 0.92, P < 0.0001) with BCM determined by DEXA and NaBr. TBW estimated by BIA was directly correlated (r = 0.96, P < 0.0001) with TBW determined by deuterium oxide dilution. The reactance to resistance ratio (Xc/R) derived from BIA was inversely correlated (r = -0.73, P < 0.0001) with the extracellular water/TBW ratio determined by NaBr/D2O. Bland-Altman analyses showed that for TBW, BIA was in excellent agreement with D2O dilution. BCM was modestly underestimated by BIA compared with the dual-energy x-ray absorptiometry/NaBr standard and was adjusted by linear regression. The coefficients of variation on repeated BIA measurements were below 4%, demonstrating test-retest reliability. BIA is a valid and reliable method of nutritional assessment in maintenance hemodialysis patients.

Absorptiometry, Photon↗
PubMed1995

[Hypomagnesemia in patients of gynecologic neoplasms following chemotherapy with cisplatin].

Serum magnesium in 79 patients of gynecologic neoplasms treated with cisplatin and their controls was measured. The results showed: (1) the average value of serum magnesium in patients following chemotherapy with cisplatin was significantly lower than in the controls; (2) the incidence of hypomagnesemia was positively correlated with the number of the courses and the total dosages of chemotherapy, being 52.9% after one to three courses of treatment and 92.0% after more than six courses of treatment; (3) the incidence of hypomagnesemia was directly related with the severity of gastrointestinal disorders; (4) serum magnesium following cisplatin chemotherapy was not correlated with serum blood urea nitrogen (BUN). Hypomagnesemia is clinically characterized by symptoms of the nervous system which are found in 14.0% of hypomagnesemic patients.

Adult↗