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Biomedical subjects

H Ye

Publications and source records attributed to H Ye.

At least 109 records · Page 6Linked to original sources
PubMed1994

Phosphatidic acid increases in response to noradrenaline and endothelin-1 in adult rabbit ventricular myocytes.

OBJECTIVE: The aim was to assess whether noradrenaline and endothelin-1 can stimulate endogenous production of phosphatidic acid in adult ventricular myocytes. METHODS: After stimulation of rabbit ventricular myocytes with noradrenaline and endothelin-1, total lipids were extracted using the Bligh and Dyer procedure and separated by thin layer chromatography, and phosphatidic acid was quantified using photodensitometric analysis of visualised lipids with CuSO4/H3PO4. RESULTS: Noradrenaline (10(-5) M) elicited a rapid increase in phosphatidic acid at 2 min, followed by a decrease at 5 min. A second delayed and sustained increase in phosphatidic acid occurred at 10 min. The response to noradrenaline (10(-9) to 10(-5) M) was concentration dependent with a half maximum response (EC50) of 3.1 x 10(-8) M and the maximum effect at 10(-6) M. The increase in phosphatidic acid production in response to noradrenaline was abolished by an alpha 1 adrenergic receptor blocking agent (2-[beta-(4-hydroxyphenyl)-ethylaminomethyl]tetralone) but unaffected by the beta adrenergic blocking agent L-propranolol. An increase in phosphatidic acid was also elicited in rabbit ventricular myocytes in response to endothelin-1. The response was time and concentration dependent with the maximal increase at 12 min, EC50 5.3 x 10(-9) M, and maximum effect at 10(-6) M. Both noradrenalin and endothelin-1 stimulated phosphatidylbutanol production in the presence of butanol (100 mM), indicating that both agonists activate phospholipase D. CONCLUSIONS: Noradrenaline at physiological concentrations elicits both a rapid and a delayed increase in phosphatidic acid in adult rabbit ventricular myocytes. Endothelial-1, at physiological concentrations, also stimulates an increase in the mass of phosphatidic acid in myocytes, but the increase induced by endothelin-1 is monophasic, in contrast to the biphasic response seen during stimulation with noradrenaline. Activation of phospholipase D contributes to the increase in phosphatidic acid seen during stimulation of myocytes with either noradrenaline or endothelin-1. These are the first data to characterise endogenous production of phosphatidic acid in isolated adult ventricular myocytes.

Adrenergic alpha-Antagonists↗
PubMed1994

Stable and temperature-sensitive transformation of rat kidney epithelial cells suppresses expression of acidic fibroblast growth factor 1 but activates secretion of fibroblast growth factor 3 (int-2) and vascular endothelial growth factor.

Rat kidney proximal tubule epithelial cells (RPTE) in primary culture express acidic fibroblast growth factor 1 (FGF-1). Transformation of RPTE by SV40 (SV-RPTE) suppressed FGF-1 expression but activated secretion of FGF-like factor(s). SV-RPTE conditioned medium contained growth-promoting activity for SV-RPTE and human umbilical vein endothelial cells, indicating that both autocrine and angiogenic factors were secreted. Reverse transcriptase-polymerase chain reaction and Northern analysis for various FGFs showed that only FGF-3, also known as int-2, mRNA was expressed in SV-RPTE. In addition, expression of mRNA for the heparin-binding angiogenic factor vascular endothelial growth factor (VEGF) increased dramatically in SV-RPTE. Physical characterization of the activity in the SV-RPTE conditioned medium suggested that FGF-3 and VEGF contributed the autocrine and angiogenic activities, respectively. We also investigated FGF-3 and VEGF secretion in temperature-sensitive (ts) SV40-transformed RPTE. tsSV-RPTE had transformed properties resembling those of SV-RPTE only at the permissive temperature (33 degrees C), e.g., increased growth potential and anchorage-independent growth. FGF-1 was expressed only at the nonpermissive temperature. VEGF mRNA levels and secretion of the human umbilical vein endothelial cell growth-promoting activity were reduced by switching tsSV-RPTE cells from 33 degrees to 39 degrees C. However, FGF-3 mRNA levels were not affected significantly by the temperature switch suggesting that activation of VEGF and FGF-3 occurs through different mechanisms. These results indicate that FGF-1 expression in RPTE is suppressed by SV40 transformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Myocardial function after fluid resuscitation with addition of 1-6-FDP in severely burned rabbits].

An experimental study is designed for the evaluation of the effect of fluid resuscitation with addition of 1-6FDP on myocardiac function in severely burned rabbits. 60 rabbits were divided into four groups. Group A (n = 15) served as control without treatment. The animals in group B (n = 15) were treated with 1-6-FDP immediately after burning. The animals in group C (n = 15) were treated with balanced saline solution (BSS). The animals in group D(n = 15) were treated with BSS plus 1-6-FDP. All rabbits sustained 25% TBSA full thickness burn. LVSP, LV +/- dp/dt max and PV were measured before burn, immediately after burn, and 1, 3, 5, 7 h, after burn, except that PV was not measured immediately after burn. The results showed that depression in myocardial contractility and relaxation were noted immediately after severe burn. Fluid resuscitation alone did not significantly improve myocardial function (P > 0.05 compared with control). The administration of 1-6-FDP showed a beneficial effect in improving myocardial contractility and relaxation within 3 hours postburn. With fluid resuscitation plus 1-6-FDP, myocardial contractility and relaxation were improved statistically significantly as compared with the control group (P < 0.01).

Animals↗
PubMed1994

[Leukemia associated with bimkolane].

Psoriatic patients and mice treated with bimolane were observed. The frequency of chromosomes aberration and micro-nuclear cells presence in the treated group (11 cases) was significantly higher than that in the control group (11 cases, P < 0.005; < 0.001). Study of lymphocytic subsets showed that value of CD4/CD8 in the peripheral blood of the treated group was lower than that of the control group (P < 0.05). The level of serum IgM in the treated group was also lower (P < 0.05). There were 10 mice suffering from leukemia (7 mice with acute promyelocytic leukemia) in a treated group of 40 mice of an inbred line of 615 mice, while there was no leukemia in a control group of 20 mice of the same species. The morbidity of leukemia in the treated mice was higher than that of controls (P < 0.05).

Adolescent↗
PubMed1994

[Bacteriological detection of anterior chamber aspirate after extracapsular cataract extraction with intraocular lens implantation].

We cultured the anterior chamber aspirates of 83 patients with extracapsular cataract extraction and IOL implantation. Of the 83 cases, 5 (6.1%) had positive aspirates including 3 cases of staphylococcus epidermidis and 2 cases of staphylococcus aureus. No eye in our study developed bacterial endophthalmitis. Our study suggests that the anterior chamber of human eyes is capable of clearing a low inoculum of bacteria after cataract surgery without the development of bacterial endophthalmitis.

Aged↗
PubMed1994

[Biological effects of diagnostic ultrasound on embryo in first trimester of pregnancy].

Biological effects of diagnostic ultrasound on the embryo during first trimester of pregnancy were studied. Normal pregnant women asked for induced abortion with gestational age of 6-8 weeks were recruited. Embryo in uterus were exposed to the diagnostic ultrasound for 5, 10 and 30 minutes respectively. Surgical evacuations were performed 5, 15, 24 and 48 hours after exposure and chorionic villi were obtained. The villi were determined for 4 lysosomal enzymes, malondialdehyde (MDA), and superoxide dismutase (SOD); and sister chromatid exchange and the ultrastructure of the villi were studied as well. In comparison to normal non-exposure group, the results showed various degrees of changes in lysosomal enzymes, MDA, SOD and ultrastructure of the villi in those exposed to ultrasound 10 and 30 minutes, and most significant changes were observed in the latter group. These included the hyperreaction of lipid peroxides; increased activities of some lysosomal enzymes; reduced SOD activity; and vesiculation and aberration of some mitochondrion, also transformation or disappearance of some microvilli in ultrastructure.

Adult↗
PubMed1993

Biphasic generation of diacylglycerol by angiotensin and phorbol ester in bovine adrenal chromaffin cells.

Stimulation of angiotensin receptors in bovine adrenal medullary cells with Sar1-angiotensin II increased diacylglycerol levels in a biphasic fashion. An initial peak occurred at 3 min and an increase was observed again at 60 min and even at 18 hrs. Phorbol 12-myristate 13-acetate produced a similar pattern of increase in diacylglycerol levels. Both the angiotensin analog and the phorbol ester also increased the release of (3H)choline into the culture medium from prelabelled cells. The long-term diacylglycerol production could be derived from phosphatidylcholine rather than from the phosphoinositides. The latter may be the source of the angiotensin stimulated initial production of diacylglycerol and activation of PKC. Activated PKC then turns on the continuous production of DAG which maintains PKC in an active state for long periods of time in the presence of the peptide.

Adrenal Medulla↗
PubMed1993

Role of omega-conotoxin GVIA-sensitive Ca2+ entry in angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding in bovine adrenal medullary cells.

The relative contributions of Ca2+ influx and intracellular Ca2+ mobilization were examined for angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding, which reflects the level of activated protein kinase C in bovine chromaffin cells. Angiotensin II receptors activate phospholipase C in chromaffin cells, leading to a short-lived mobilization of intracellular Ca2+. Angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding was largely blocked in Ca(2+)-free buffer and by pretreatment with the Ca(2+)-channel blocker omega-conotoxin GVIA. The [3H]phorbol 12,13-dibutyrate binding response to [Sar1]angiotensin II also appeared to be voltage sensitive, as no additivity was observed with the response to the depolarizing agent 4-aminopyridine (3 mM). Threshold sensitivities of the extra- and intracellular Ca(2+)-mobilizing pathways to angiotensin II were similar, and all examined effects of angiotensin II in these cells were apparently mediated by losartan-sensitive (AT1-like) receptors. The dependence of angiotensin II-stimulated [3H]phorbol 12,13-dibutyrate binding on extracellular Ca2+ entry, in contrast to stimulation by other phospholipase C-linked receptor agonists (bradykinin and methacholine), suggests that angiotensin II preferentially stimulates protein kinase C translocation to the plasma membrane, rather than to internal membranes, in bovine adrenal medullary cells.

Adrenal Medulla↗
PubMed1993

Glaucoma: changes in extracellular matrix in the optic nerve head.

Primary open angle glaucoma (POAG), the most common form of glaucoma, is characterized by irreversible loss of axons from the optic nerve. The site of damage to the axons is at the level of the lamina cribrosa in the optic nerve head. It has been hypothesized that structural and biochemical abnormalities in the extracellular matrix (ECM) of the lamina cribrosa underlie the progressive compressive and remodelling of this connective tissue in glaucoma. In this review, we present evidence of specific changes in collagen and elastic fibers, major ECM components in the lamina cribrosa of glaucomatous eyes.

Collagen↗
PubMed1992

A 35 kDa Fos-related antigen is co-localized with substance P and dynorphin in striatal neurons.

The rat striatum after dopamine denervation followed by repeated apomorphine treatment was examined for the co-expression of c-fos and Fos-related antigens with dynorphin, substance P and [Met5]enkephalin using Western blot and immunohistochemical techniques. Administration of apomorphine, a dopamine agonist, elevated the level of 35 kDa Fos-related antigen which co-localized with dynorphin and substance P, but not enkephalin, in striatal neurons.

Animals↗
PubMed1992

Apomorphine induction of AP-1 DNA binding in the rat striatum after dopamine depletion.

The expression of AP-1 transcription factors was assessed in the dopamine-depleted rat striatum over a 1 week period of repeated apomorphine injections. A single injection of apomorphine increased the expression of a 35 kDa Fos-related antigen and Jun proteins and their expression continued to increase until day 3 of repeated apomorphine treatment in dopamine-depleted striata. Apomorphine induces AP-1 transcription factors which may be involved in modulating gene expression in the striatum.

Animals↗
PubMed1992

Long-term activation of protein kinase C by nicotine in bovine adrenal chromaffin cells.

Previous results from our laboratory suggest that long-term treatment of primary cultured bovine adrenal medullary (BAM) chromaffin cells with nicotine or phorbol 12-myristate 13-acetate, either of which directly activates protein kinase C (PKC), increases the mRNA levels encoding catecholamine-synthesizing enzymes and proenkephalin. In the present study, we have examined the effects of nicotine on BAM cell PKC activity with special emphasis on long-term effects. Nicotine increased particulate PKC activity in a concentration-dependent manner when measured using in vitro enzyme assay with histone as the substrate. This effect is mediated through nicotinic cholinergic receptors, because 1,1-dimethylphenylpiperazinium, a nicotinic agonist, had a similar effect. In addition, chlorisondamine, a specific nicotine-receptor blocking drug, antagonized the effect of nicotine. Nicotine also increased specific [3H]phorbol 12,13-dibutyrate ([3H]PdBu) binding within 1 min, the effect of which was maximal between 3 and 12 min. This effect was reversed by chlorisondamine similarly after 12 min and after 18 h of nicotine treatment, indicating that continual nicotinic-receptor occupancy is required for persistent PKC activation. Compared to PKC activation, the onset of nicotine-stimulated diacylglycerol production was slow, and it was observed after 12 min of incubation with nicotine. The diacylglycerol levels, specific [3H]PdBu binding, and PKC activity remained significantly elevated for at least 18 h with continuous nicotine incubation. Furthermore, nicotine increased the PKC immunoreactivity of a particulate protein with a molecular mass of 82 kDa in the western blot. These results suggest that nicotinic-receptor activation increases PKC activity and immunoreactivity in BAM cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1991

Long-term activation of protein kinase C by angiotensin II in cultured bovine adrenal medullary cells.

Previous studies from our laboratory suggest that protein kinase C (PKC) is involved in the angiotensin II (AII)-induced increase in the expression of genes encoding proenkephalin and catecholamine biosynthesizing enzymes in primary cultured bovine adrenal medullary (BAM) cells. The purpose of this study was to examine the effects of [Sar1]-AII (S1-AII), an AII agonist, on PKC activity in BAM cells. Thirty-minute incubation with S1-AII produced a dose-dependent activation of PKC. The particulate PKC activity was significantly increased by 2 nM S1-AII after both 30 min and 12 h of incubation. A high concentration of S1-AII (200 nM) caused an increase in particulate PKC activity after 30 min of incubation and this increase was still observed after 18 h of continuous incubation. [Sar1, Thr8]-angiotensin II (S1, T8-AII) (100 microM), an AII antagonist, inhibited the effect of S1-AII (20 nM) on PKC activity, suggesting a specific AII receptor-mediated effect. An increase in BAM cell particulate PKC immunoreactivity after 18 h of S1-AII treatment was observed in Western blot analysis of PKC-immunoreactive protein (82 kDa). The persistent activation of PKC seen in this study is consistent with our hypothesis that PKC may mediate the S1-AII-induced increase in the expression of genes encoding proenkephalin and catecholamine synthesizing enzymes in BAM cells.

Adrenal Medulla↗
PubMed1991

Study of the malaria situation in forested foothill and nearby plain areas of Myanmar.

A longitudinal demographic-parasitological survey on malaria was conducted at 10 weekly intervals starting from September in one foothill village with the population of 1,095 and one epidemiologically comparable plain village with the population of 962 in Kyauktaga township, Bago division, 120 miles north of Yangon. The objective was to describe and analyse the current malaria situation in a forested foothill area and an adjacent plain area. Ten weekly blood film collections for malaria parasite examination, six monthly sera collections on filter paper for serological examination from the whole study population and ten weekly splenic measurements from 2-9 year children were done. The malaria parasite rate in the foothill area was invariably higher than that in the plain area in all age groups throughout the study period. Moreover, the parasite rate decreased with the increase in distance from the forested foothill area indicating that the deep forest malaria may have some influence on the foothill villages. The total age specific parasite rate in foothill villages was found to be highest in the 5-8 year age group and decreased as the age advanced which may be due to the increasing immunity. The study revealed the presence of local transmission in the foothill village. From these data it is evident that new village sites should be chosen at least 5 miles away from the forest fringe and the malaria control measures in the plain area should utilize chemoprophylaxis and effective chemotherapy focusing on the people who travel into the forest.

Adolescent↗