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W Huang

Publications and source records attributed to W Huang.

At least 613 records · Page 34Linked to original sources
PubMed1992

In vitro evidence for modulation of morphological and functional development of hypothalamic immunoreactive atrial natriuretic peptide neurons by cyclic 3',5'-adenosine monophosphate.

In the hypothalamus of the rat, the precursor of atrial natriuretic peptide (ANP) is produced and processed into its smaller congeners of 3K mol wt species, which are secreted from neurons with cell bodies in the periventricular areas and the paraventricular nuclei of the tissue. Employing long term monolayer cultures of neonatal rat hypothalamic cells, we have identified a small population of cells that stained positive for immunoreactive (ir) ANP. Seventy-two +/- 7% (mean +/- SE; n = 4 per 1000 cells) of the irANP positive cells were colocalized with the staining of neuron-specific enolase; some of the cells possessed multiple neurites and showed irANP staining in the perikarya, in the varicosities along neuronal processes, and at the terminals of long neurites. Over the range of 10(-6)-10(-4) M, forskolin, 3-isobutyl-1-methylxanthine, or 8-bromo-cAMP significantly augmented the total number of irANP-positive cells and those possessing neurites in a dose-related and time-dependent manner. At 10(-4) M, 4 days of forskolin treatment increased the number of irANP-positive neurons 4-fold (P less than 0.01) while tripling that of the cells with long neurites (P less than 0.01). Furthermore, it approximately tripled the number of cells (P less than 0.01) showing positive signals for pro-ANP mRNA, as ascertained by colorimetric in situ hybridization using a 30-basepair antisense oligonucleotide probe labeled with digoxigenin. Consistent with the above observation, forskolin, 3-isobutyl-1-methylxanthine, or 8-bromo-cAMP treatment significantly augmented the total amount of irANP present in the cultures, with an ED50 of forskolin approximating 5 x 10(-5) M. Although treatment with 10(-7) M phorbol 12-myristate 13-acetate approximately doubled the production of irANP in the cultures (P less than 0.05), phorbol 12-myristate 13-acetate had little effect on modulating the number or neurite outgrowth of irANP neurons. Thus, our present findings suggest that protein kinase-A pathways are of greater importance than protein kinase-C pathways in regulating both the functional and morphological development of ANP-producing neurons during the ontogenesis of the rat hypothalamus.

1-Methyl-3-isobutylxanthine↗
PubMed1992

Evidence for atrial natriuretic peptide-(5-28) production by rat placental cytotrophoblasts.

Atrial natriuretic peptide (ANP), a 28-amino acid peptide, is produced and secreted by cardiac atriocytes to modulate cardiovascular and renal functions. We report here the production of ANP-(5-28) and its 15K mol wt (M(r)) presumptive precursors by cytotrophoblasts of rat placentae. Placental tissues were collected from Sprague-Dawley fetal rats on days 12, 16, 18, and 20 of gestation and acid extracted for immunoreactive (ir) ANP assay. The contents of placental irANP increased over the course of fetal growth, with the highest amount (mean +/- SE, 1083 +/- 125 pg/tissue; n = 7) found near term. Sephadex G-50 gel chromatographic profiles of the placental extract revealed a major peak of irANP coeluted with the 3K M(r) of synthetic rat (r) ANP-(1-28) and a minor peak in the position consistent with that of 15K M(r). HPLC analysis of the 3K M(r) species showed a single peak of immunoreactivity, which eluted with a retention time similar to that of rANP-(5-28). In placental sections, irANP and pro-ANP mRNA were localized by immunoperoxidase staining and colorimetric in situ hybridization in a subpopulation of placental cytotrophoblasts, but not in syncytiotrophoblasts or chorionic cells. Northern blot analysis showed a single band of pro-ANP mRNA in rat placental tissues similar in size to that found in the heart (approximately 0.85 kilobases), with the highest level of pro-ANP mRNA signal detected in the placentae of 16-day gestation fetuses. Our findings suggest that ANP is expressed and produced by a small population of rat placental cytotrophoblasts and that the 15K M(r) precursor peptide is extensively processed into the N-terminal-truncated form of ANP-(5-28) in the tissue.

Animals↗
PubMed1992

Plasticity of adrenoceptor responsiveness on irANP secretion and pro-ANP mRNA expression in hypothalamic neuron cultures: modulation by dexamethasone.

Atrial Natriuretic Peptide (ANP) or its smaller congeners are produced and secreted from the rat hypothalamus. Whereas immunoreactive (ir)ANP secretion and proANP mRNA expression in hypothalamic cell cultures of neonatal rats were augmented by norepinephrine acting through its alpha 2-adrenoceptors (AR), in the perifusion studies of adult hypothalamic fragments beta-AR was involved in the upregulation of irANP release. Here, we report that dexamethasone (DM) modulates irANP secretion and pro-ANP mRNA expression from hypothalamic neurons in culture by switching the adrenoceptor responsiveness of the cells from alpha 2- to that of beta-AR. In long term cultures of hypothalamic cells, treatment with clonidine (alpha 2-AR agonist) increased irANP secretion in a dose related manner. This effect of clonidine was abolished by DM, a glucocorticoid which by itself had little effect on the basal release of irANP. In contrast, isoprenaline, a beta-AR agonist which was ineffective when applied alone, enhanced irANP secretion from hypothalamic cultures in the presence of DM. Concurrent incubation of DM (5 nM) and isoprenaline (10 microM) augmented irANP release approximately 3 fold above that of cultures treated with DM alone (22.6 +/- 2.2; mean +/- SE, n = 4). However, phenylephrine, an alpha 1-AR agonist alone or in the presence of DM failed to stimulate irANP release. These immunoassay findings were accompanied by corresponding changes in the abundance of pro-ANP mRNA in the cultures as examined by colorimetric Northern blot analysis employing a 30 mer oligonucleotide probe corresponding to the first 10 amino acid sequence of rANP1-28. We conclude from the above observations that glucocorticoids modulate irANP secretion and pro-ANP mRNA expression in hypothalamic neurons by altering the responsiveness of the cells from alpha 2-AR to that of beta-AR.

Animals↗
PubMed1992

Detection of antigens associated with lung carcinoma in sera by monoclonal antibodies WLA-2C4 and CL-3.

The levels of tumor-associated antigens (TAAS) corresponded to monoclonal antibodies WLA-2C4 and CL-3 in sera of 57 lung cancer patients, 100 healthy adults and 50 non-tumor disease patients were assayed with SABC-ELISA of immunobinding inhibition test. The threshold values of WLA-2C4 and CL-3 (RBI) were 12% and 36%, respectively. The positive results of lung carcinomas with at least one of the two TAAS were as follows: squamous cell carcinoma 89%; adenocarcinoma 83%; small cell carcinoma 67% and their mean positive rate was 79%. Whereas the positive rate in healthy adults and non-tumor disease patients was only 6%. These results indicate that using monoclonal antibodies WLA-2C4 and CL-3 simultaneously may be helpful to the serological diagnosis of lung carcinoma.

Adenocarcinoma↗
PubMed1992

Molecular rearrangements of the MYL gene in acute promyelocytic leukemia (APL, M3) define a breakpoint cluster region as well as some molecular variants.

Genomic DNA probes generated from the retinoic acid receptor alpha (RARA) gene located on chromosome 17 and from the MYL gene located on chromosome 15 were used to study the chromosome 15 breakpoints resulting from the t(15; 17) translocation in 26 patients with acute promyelocytic leukemia (APL). In 20 out of 22 patients with a detectable MYL rearrangement, the breakpoints were clustered within a 4.4 kb segment designated MYLbcr. The two remaining patients exhibited a more 5' rearrangement at about 10 kb upstream of the MYLbcr region, implying the lack of at least one MYL gene exon in the resulting MYL-RARA fusion gene. The variation of chromosome breakpoints within the MYL gene may explain size heterogeneity previously observed in some MYL-RARA fusion transcripts expressed in APL cells.

Blotting, Southern↗
PubMed1992

[Application of the regression orthogonal design to the fertilization of Psoralea corylifolia L. for optimum yield].

This paper probes into the determination of the optimum amount of fertilization by applying regression orthogonal design. After a significance test by regression equation, a regression equation can be set up, i. e. Y = 25.21 + 9.18 Xn + 15.68 Xp - 0.4 Xn2 - 0.98 Xp2 + 0.062 Xn Xp. This equation can be used to describe the relationship between yield and amount of fertilization.

Fertilizers↗
PubMed1992

Protective effects of berberine and phentolamine on myocardial reoxygenation damage.

The protective effects of berberine and phentolamine against anoxia and reoxygenation damage in isolated rat hearts have been investigated. Incorporation of berberine (24.5 mumol/L) in both anoxic and aerobic perfusion media resulted in a significant reduction of CPK release during the reoxygenation period, and the ultrastructural damage was reduced as compared with the control group; the myocytes in the berberine-treated group displayed mild intracellular edema, well-registered myofibrils without contracted bands, and swollen mitochondria with partially broken cristae but without dense bodies. Berberine did not inhibit calcium and sodium accumulation or magnesium and potassium loss. Treatment with phentolamine (6.6 mumol/L), an alpha-adrenoceptor antagonist, had similar effects, though the CPK release profile was shifted to the right and downwards. These results suggest that although berberine and phentolamine have some beneficial effects on myocardial reoxygenation injury, they may not abolish the injury. Therefore alpha-adrenoceptor stimulation may not be the major mechanism behind the injury.

Adrenergic alpha-Antagonists↗
PubMed1992

[Granule-making technology for preparing luohanguo chrysanthemum granule medicine with orthogonal design].

L9 (3(4)) orthogonal design was adopted to inspect the consumption of white sugar, water and ethanol and the duration of raw material mixing in relation to the granule-attaining rate in preparing Luohanguo-Chrysanthemum granule medicine. The result shows that with a consumption of 170 kg of white sugar, 6000 ml of water and 800 ml of ethanol and a duration of 8 minutes, the granule attaining rate reaches about 80%.

Drug Combinations↗
PubMed1991

Rearrangements in the second intron of the RARA gene are present in a large majority of patients with acute promyelocytic leukemia and are used as molecular marker for retinoic acid-induced leukemic cell differentiation.

Chromosome 17 breakpoints in translocation t(15;17), a hallmark for acute promyelocytic leukemia (APL), have been shown to disrupt the retinoic acid receptor-alpha (RARA) gene. In this study, DNA probes around the second exon of the RARA gene showed rearrangements not previously detected. Analysis of 25 Chinese APL cases showed that RARA gene rearrangements were present in 23 cases (92%). The breakpoints were mapped unequivocally in 22 cases within the second intron of the gene. Therefore, the RARA gene rearrangement provides us with a specific marker of the disease. Simultaneous molecular and cytologic studies showed that the RARA gene rearrangements persisted during the first 2 to 3 weeks of all-trans retinoic acid (ATRA) therapy when differentiated granulocytes predominated in bone marrow, while these rearrangements disappeared after achieving complete remission. These data indicate that ATRA induces differentiation of APL cells.

Adolescent↗
PubMed1991

Growth in high serum concentrations leads to rapid deadaptation of cells previously adapted to growth in an extremely low concentration of serum.

A subline of NIH 3T3 cells adapted to multiply in 0.25% calf serum (CS) by frequent passage (every 2-3 days) at low population density in 0.25% CS was deadapted by frequent successive passages of the cells in 10% CS for 3 weeks. The cells adapted to 0.25% CS multiplied with an average doubling time of 16.9 hr in 10% CS, and cells that had always been kept in 10% CS multiplied with an average doubling time of 14.6 hr, so there was weak selection for the latter in the higher serum concentration. When adapted cells were subjected to two passagers in 10% CS prior to assay of growth in 0.25% CS, a 4-day lag period was evident before commencement of exponential growth, and there was a decrease in saturation density. Further delay of growth in 0.25% CS developed as the number of passages of cells in 10% CS increased. The marked delay of growth in 0.25% CS of the bulk population after a few days in 10% CS argued against selection in 10% CS of rare nonadapted mutants from the adapted population and for an epigenetic origin of the change. Reconstruction experiments utilizing adapted cells mixed with non-adapted cells in 0.25% CS buttressed this explanation. Eight clones of the adapted population exhibited some loss of growth capacity in 0.25% CS after a single passage in 10% CS, though the extent of loss varied from clone to clone. The results support the idea that all cells in the adapted population respond to the lifting of growth constraints with loss of their growth potential under highly constrained conditions. They are consistent with the concept of progressive state selection in which selection operates on fluctuating metabolic states of individual cells rather than on genetic variants.

3T3 Cells↗
PubMed1991

Forskolin-induced immunoreactive atrial natriuretic peptide (ANP) secretion and pro-ANP messenger ribonucleic acid expression of hypothalamic neurons in culture: modulation by glucocorticoids.

In the present studies the chronic effects of glucocorticoids and drugs activating cAMP-dependent pathways on the production and secretion of immunoreactive (ir) ANP from long term monolayer cultures of neonatal rat hypothalamic neurons were examined. Forskolin treatment increased ir-ANP release in a time-dependent and dose-related manner, with an EC50 of approximately 30 microM; at a lower dose of 10 microM, forskolin doubled ir-ANP release (P less than 0.01) compared to that in control cultures (mean +/- SEM, 9.6 +/- 0.3 pg/well; n = 4). While dexamethasone (DM) alone did not affect basal secretion of ir-ANP, 10 nM of the glucocorticoid significantly enhanced the effect of forskolin (10 microM) by raising ir-ANP release approximately 3 times that induced by forskolin alone (P less than 0.001). This potentiation of DM was both time dependent and dose responsive, with an EC50 of 1 nM; this effect was significantly suppressed by 100 nM RU38486, a glucocorticoid or type II receptor antagonist, but not by RU28318, a mineralocorticoid receptor antagonist. In addition, forskolin (10 microM) or DM (10 nM) alone significantly increased ir-ANP production approximately 1.4 times (P less than 0.05) and 1.3 times (P less than 0.05) over that of control cultures, respectively, whereas concurrent treatment with forskolin and DM increased ir-ANP production by approximately 1.8 times (P less than 0.01). These changes were reflected by a corresponding increment in the abundance of pro-ANP mRNA in the cultures, as demonstrated by Northern blot analysis. We conclude from the present findings that glucocorticoid- and cAMP-dependent pathways may modulate the function of ANP neurons in rat hypothalami by regulating the secretion and production of the neuropeptide at the genomic level.

Animals↗
PubMed1990

Analysis of biogenic amines and their metabolites in biological tissues and fluids by gas chromatography-negative ion chemical ionization mass spectrometry (GC-NICIMS).

GC-NICIMS has been employed in the analysis of biogenic amines and their metabolites in human urine and human, bovine and porcine aqueous and vitreous humour. Several new chemical derivatization procedures have been developed in order to analyse these compounds. Concentrations of octopamines and synephrines were determined in urine from treated and untreated hypertensive subjects and normotensive individuals; there were no significant differences in concentrations of these metabolites between these groups. Human urine contained several dihydroxy-phenylethylamines which have not been reported as natural metabolites before and also 5- and 6-hydroxydopamine in relatively large amounts. Aqueous and vitreous humour contained very low quantities of noradrenaline, tyramine and dopamine but measurements were inconsistent because sometimes the levels were below the limits of detection. Metabolites of a number of biogenic amines were readily detected in aqueous and vitreous humour.

Animals↗
PubMed1990

Hypothalamic atrial natriuretic peptide secretion plasticity: differential modulation of alpha and beta adrenoceptors.

Increasing evidence suggests that atrial natriuretic peptide (ANP), a 28 amino acid peptide with biologically active 4-28 and 5-28 congeners, modulates salt-water homeostasis at both peripheral and central levels. In rats, immunoreactive (ir) ANP is found in hypothalamic (HT) neurons of preoptic and paraventricular regions rich in aminergic innervation. Employing a well-characterized perifusion model of rat HT explants, the acute effects of norepinephrine (NE) on HT release of irANP were examined. Pulsatile administration (20 min) of NE (10(-7) to 10(-5) M) induced a dose-related release of irANP. The stimulatory effect of 10(-5) M NE (2.66 +/- 0.54 pg/ml/HT, means +/- SE, n = 12) was abolished in the presence of 10(-7) M propranolol, a beta-antagonist, but was 50% higher when administrated with 10(-5) M phentolamine, an alpha-antagonist. Administration of equivalent doses of propranolol or phentolamine alone, consistently suppressed (40% below basal secretion rate, BSR) or stimulated (50% above BSR) irANP release, respectively. In addition, infusion of isoprenaline (10(-5) M), a beta-agonist, enhanced BSR by 45%, whilst phenylephrine (10(-5) M), an alpha-agonist, suppressed it by 25%. We conclude that in rat hypothalami (1) occupancy of the beta-adrenoceptor by its agonist stimulates irANP release, (2) alpha- and beta-adrenoceptors modulate irANP secretion in an opposing manner, and (3) the basal release of irANP is a product of the activation of alpha- and beta-adrenoceptors by their endogenous ligands.

Animals↗
PubMed1990

[Ventricular tachyarrhythmias treated with berberine].

The effects of berberine on 100 cases with ventricular tachyarrhythmias observed with 24 to 48 hour ambulatory monitoring were reported. The results showed that 62% of patients had 50% or greater, and 38% of patients had 90% or greater VPC suppression. The mean value of VPCs in whole group was significantly decreased by berberine from 452 +/- 421.8 beats per hour to 271 +/- 352.7 beats per hour (P less than 0.001). These results revealed that berberine is effective for ventricular tachyarrhythmias. There were no severe side effects, only mild gastroenterologic symptoms were observed in some patients.

Adolescent↗