Biomedical subjects

Bin Geng

Publications and source records attributed to Bin Geng.

24 records · Page 2Linked to original sources

PubMed2004

H2S generated by heart in rat and its effects on cardiac function.

Hydrogen sulfide (H2S), which was considered as a novel gasotransmitter, is produced endogenously from L-cysteine in mammalian brain and vessels, and might be a physiological function regulator to these organs. Here, we showed that mRNA for H2S producing enzyme, cystathionine gamma-lyase, was expressed in myocardial tissues and H2S could endogenously be produced in myocardial tissues. Negative inotropic effect of H2S was proved in present study in vitro and in vivo experiments, and the effect could partly be blocked by glibenclamide, a KATP channel blocker. An intravenous bolus injection of NaHS provoked a decrease in central venous pressure. The present findings suggested that H2S could be endogenously produced by heart tissues, as a physiological cardiac function regulator, mediated by KATP channel pathway.

Animals↗

PubMed2004

Protective effects of ghrelin on ischemia/reperfusion injury in the isolated rat heart.

Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor, has been reported to have beneficial effects on cardiac function. The authors used the Langendorff model of ischemia/reperfusion (I/R) injury in isolated rat heart to determine whether ghrelin exerts direct cardioprotective effects. Also, the capacity of ghrelin to bind to sarcolemmal membrane fractions before and after ischemia and reperfusion was examined. Compared with vehicle administration, administration of ghrelin (100-10,000 pM) during the reperfusion period resulted in improvement in coronary flow, heart rate, left ventricular systolic pressure, and left ventricular end-diastolic pressure. Ghrelin also enhanced the rates of left ventricular contraction and relaxation after ischemia following reperfusion. Administration of ghrelin during reperfusion reduced myocardial release of lactate dehydrogenase and myoglobin, indicating protection against cardiomyocyte injury. In addition, ghrelin attenuated the depletion of myocardial ATP resulting from ischemia and reperfusion. A receptor-binding assay demonstrated that maximum binding capacity of ghrelin to sarcolemmal membranes was significantly increased after ischemia and was further increased after I/R. However, Scatchard analysis showed that the affinity of ghrelin for its receptor was not altered. The authors have concluded that administration of ghrelin during reperfusion protects against myocardial I/R injury. The cardioprotective effects are independent of growth hormone release and likely involve binding to cardiovascular receptors, a process that is upregulated during I/R.

Animals↗

PubMed2004

[Hydrogen sulfide: a novel cardiovascular functional regulatory gas factor].

Hydrogen sulfide (H(2)S) may be endogenously produced by cystathionine beta-lyase (CBS) and cystathionine gamma-lyase (CSE) as a cardiovascular physiological functional factor. On the hypoxic pulmonary hypertension (HPH) animal model, the plasma H(2)S concentration, the gene expression and the activity (CSE) were decreased in lung tissues In L-NAME induced hypertension and spontaneous hypertension rats (SHR) models, the plasma H(2)S concentration, vascular CSE activity and mRNA expression were obviously decreased. When H(2)S was exogenously supplied, systolic pressure obviously decrease. These studies suggested that CSE/H(2)S pathway participated in the pathophysiological development of hypertension. The endogenous level of H(2)S produced by some arterial tissues increased in both septic and endotoxic shock rats. The level of H(2)S highly correlated with the endogenous level of NO. These results suggest that H(2)S may be a novel cardiovascular functional regulator.

Animals↗

PubMed2004

Ghrelin protects myocardium from isoproterenol-induced injury in rats.

AIM: To investigate the cardiac protective effects of ghrelin in rat with myocardial injury induced by isoproterenol (ISO). METHODS: Rats were subcutaneously injected ISO 40 mg/kg/d with or without ghrelin 1 or 10 nmol/kg/d for 2 d. Hemodynamic parameters including mean arterial blood pressure and left ventricular pressure were measured at 12 h after the last injection with ISO and/or ghrelin. Plasma lactate dehydrogenase (LDH) activity, plasma and myocardial contents of malondialdehyde (MDA), and conjugated diene were measured. Plasma ghrelin and endothelin-1 levels were assayed using radioimmunoassay methods. Endothelin-1 and ghrelin mRNA were determined using RT-PCR. RESULTS: About 45 % (5/11) of rats after treatment with ISO alone died during experimental periods. However, no rats died after administration with ghrelin 10 nmol/kg/d (0/11, P<0.05). Ghrelin also obviously ameliorated the hemodynamic disturbance in rats induced by ISO. The plasma LDH activity, contents of myocardial and plasma MDA, and conjugated diene level in plasma in ISO+G10 nmol/kg/d group were decreased by 28 %, 34 %, 73 %, and 38 % compared with those of ISO group (all P<0.01) respectively. ISO-induced endothelin-1 mRNA over-expression was inhibited and endothelin-1 level in plasma were inhibited by ghrelin 1 and 10 nmol/kg/d. The ghrelin levels in plasma and ghrelin mRNA in myocardium were increased in the rats after injection of ISO. The plasma ghrelin level was further increased after ghrelin administration. CONCLUSION: Ghrelin has a protective effect against ISO-induced myocardial injury.

Animals↗

PubMed2003

[Effects of adrenomedullin and proadrenomedullin N-terminal 20 peptide, alone or in combination, on the rat hearts in vitro].

OBJECTIVE: To study the effects of adrenomedullin (ADM) and proadrenomedullin N-terminal 20 peptide (PAMP) alone or in combinations on the isolated rat hearts as well as the possible signaling pathways involved in their actions. METHODS: In isolated rat hearts the left ventricular pressure (LVP), LVP+/-dp/dtmax, coronary fluid (CF) and heart rate(HR) of the hearts infused at different concentrations of ADM and/or PAMP were determined by a 4-cannal physiological recorder, then the cAMP contents were assayed in myocardium. RESULTS: After being infused with ADM from 10(-11) to 10(-8) mol x L(-1) or PAMP from 10(-11) to 10(-8)mol x L(-1), the LVP and LVP+/-dp/dtmax of the isolated hearts decreased gradually in a concentration-dependent manner, and at the same concentration, the effects of PAMP were more potent than those of the ADM. When ADM and PAMP were co-administrated with both concentrations as low as from 10(-11) to 10(-10) mol x L(-1), the cardiac parameters were decreased more than either ADM or PAMP administrated alone. However, the inhibitory effects of ADM and PAMP were attenuated when they were in combination at higher concentrations as from 10(-9) to 10(-8) mol x L(-1). When the rat hearts were infused with ADM PAMP and ADM plus PAMP, the CF were always higher than those of the controls and decreased when co-administrated with L-NAME, an inhibitor of NOS, but the decreased degree of LVP and LVP+/-dp/dtmax were attenuated by L-NAME. The cAMP contents in the left cardiac ventricle were increased significantly by ADM infusions but not changed obviously by PAMP, and were of no statistical difference in rat hearts with ADM administrated alone from those combinated with ADM and PAMP. CONCLUSION: These results showed that ADM and PAMP infused alone or in combinations inhibited the function of rat hearts in vitro, which might be partly involved with the NOS/NO pathway.

Adrenomedullin↗

PubMedDate not supplied

Parallel solution combustion synthesis for combinatorial materials studies.

A parallel solution combustion synthesis technique was developed for combinatorial materials studies. The vigorous combustion reactions were successfully limited in the microreactors by using a substrate-net-mask microreactor system and the lowest adoptable furnace temperature. Using this technique, a luminescent materials library of Y3Al5O12/Tb(chi) was synthesized with the aid of an ink-jet delivery system. Structure and luminescence characterizations were implemented using X-ray diffraction and UV/X-ray spectroscopies, respectively. The results show that this technique is reliable and applicable to combinatorial study of powder materials with high synthesis temperature.

Journal Article↗