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Biomedical subjects

R Yang

Publications and source records attributed to R Yang.

At least 199 records · Page 11Linked to original sources
PubMed1996

Prostaglandin F2 alpha induces cardiac myocyte hypertrophy in vitro and cardiac growth in vivo.

Several prostaglandins [prostaglandin (PG) A2, -B2, -D2, -E2, -F2 alpha, and -I2 and carbaprostacyclin] and the thromboxane analogue U-46619 were analyzed for the ability to induce hypertrophy of rat neonatal cardiac ventricular myocytes. Myocyte hypertrophy was induced specifically by PGF2 alpha. Myocytes exposed to this prostanoid in culture increased in size and protein content. The contractile fibrils within the cells became organized into parallel arrays, and the cells tended to cluster and beat spontaneously. PGF2 alpha also induced the expression of c-fos, atrial natriuretic factor (ANF), and alpha-skeletal actin in these cells. The effects of PGF2 alpha were compared with several known cardiac myocyte hypertrophy factors (phenylephrine, endothelin-1, leukemia inhibitory factor, cardiotrophin-1, and angiotensin II). PGF2 alpha was found to be intermediate in potency among the factors but induced a level of ANF production that was approximately 10-fold higher than any of the other effectors. Responsiveness to PGF2 alpha was not limited to neonatal cardiocytes. Ventricular myocytes isolated from adult rats also responded specifically to PGF2 alpha with a morphological change similar to that observed with phenylephrine and by producing ANF. In rats, chronic administration of fluprostenol, a potent agonist analogue of PGF2 alpha, resulted in a dose-dependent increase in heart weight- and ventricular weight-to-body weight ratios. The amount of PGF2 alpha extractable from the hearts of rats with cardiac hypertrophy induced by myocardial infarction was also found to be greater than that in sham-operated control rats. These results indicate that PGF2 alpha may play an important role in inducing cardiac hypertrophy.

Aging↗
PubMed1996

Relationship between chondroitin sulfate proteoglycan and coronary atherosclerosis in the youth.

OBJECTIVE: To study the relationship between chondroitin sulfate proteoglycan (CSPG) and coronary atherosclerosis in youth. MATERIAL AND METHODS: Immunohistochemistry of chondroitin sulfate proteoglycan and SM-alpha-actin was performed on 39 human coronary arteries, including normal vessels and vessels with fatty streaks, intermediate lesions and plaques. Some of the lesional vessels were taken for beta-lipoprotein immunohistochemical study. CSPG contents were quantitated by image analyzer and the coronary arteries from one heart were processed for immunoelectron microscopy. RESULTS: The range of CSPG distribution was extensive and CSPG area density was increased significantly in the intima with atherosclerotic lesions. The increase of CSPG was parallel to the numbers of smooth muscle cell (SMC) with positive SM-alpha-actin reaction and was likely related to the phenotype transformation of SMC. Similar distribution of beta-lipoprotein and CSPG were found within the lesional regions. CONCLUSIONS: The increase of CSPG in atherosclerotic lesion may be an important factor resulting in the deposition of lipids in the vascular wall so as to promote the formation and development of atherosclerosis.

Adolescent↗
PubMed1996

[Effect of electroacupuncture on cholecystokinin gene expression in rat hippocampus during penicillin-induced epileptic seizure].

Northern Blot and hybrization in situ techniques were used to investigate the effect of electroacupuncture (EA) on the changes of cholecystokinin (CCK) mRAN levels of the hippocampus in rat penicillin-induced epilepsy model. Epilepsy can significantly increase CCK mRNA levels in dentate gyrus and CA3 areas of hippocampus in diencephalic sections after penicillin-induced seizure, whereas EA not only can attenuate the seizure behaviors and EEG changes, but also can decrease the increase of CCK mRNA contents induced by the seizure. However, in the subiculum, dentate gyrus and CA3 areas of mesencephalic sections of rat hippocampus, EA can further increase the enhancement of CCK mRNA concentration induced by penicillin-induced seizure. The results suggest that EA inhibitory effects on the seizure's behaviors and epileptiform activities may be related to the alteration of CCK gene expression in the different area of hippocampus.

Animals↗
PubMed1996

[Pathology of endothelium, extracellular matrix and smooth muscle in gastric coronary vein of cirrhotic patients].

Immunohistochemical stain was used to observe the pathology of endothelium, extracellular matrix (ECM), vascular smooth muscle cell (VSMC) in gastric coronary vein of 30 cirrhotic patients and 10 controls. There was widespread destruction to endothelium, intravenous thrombosis, aggregation of pericyte, smooth muscle hyperplasia, and increased FN, LN, collagen IV and smooth muscle actin in the wall of the coronary vein in cirrhotic patients. The thickness of the wall and its smooth muscle were 3.07 +/- 1.03 mm and 2.31 +/- 0.76 mm respectively in cirrhotic patients, and 1.65 +/- 0.49 mm and 0.88 +/- 0.20 mm in non-cirrhotic patients (P < 0.01). Based on these observations a new concept of portal hypertensive vasculopathy was put forward.

Adult↗
PubMed1996

[Methylene blue staining in fiberoptic bronchoscopy in the diagnosis of bronchial tumors].

47 patients were stained by using methylene blue in fiberoptic bronchoscopy. Of these, 35 had central lung cancer, and 12 bronchitis. 40 patients with central lung cancer were detected by general fibreoptic endoscopy. The results demonstrated that normal bronchial mucosa was not stained, 97.14% central malignant bronchial tumors stained, and 8.33% bronchitis stained. X2test showed the marked difference. Positive diagnosis was 97.06% in biopsy specimens stained, it was higher than 77.05% in the general investigated (P < 0.05). Using methylene blue in fiberoptic bronchoscopy would help diagnose central lung cancer, determine tumors limits, permit accurate biopsy. The stain was not related to the pathological classification, differentiation of cancer cells, and classification of clinical pathology (P > 0.05).

Adult↗
PubMed1996

[The coronary artery structure and early atherosclerotic lesions of 80 young adults cases in the Ningbo fishing region].

In order to study the coronary artery structure in relation to early atherosclerotic lesions of young adults residing in a fishing region, coronary arteries from 80 autopsies of people aged 15 to 39 years who died from accidents were collected and studied by pathohistological, immunohistochemical and morphometric methods. The results showed an 18.67% prevalence of Sudanophilic lesions in the right, coronary artery, the thickness of the intima of the left anterior descending branch increased with increasing age in males, but no significant difference was observed in females, the density of the coronary artery cell nuclei decreased with increasing age. The prevalence of fatty streaks and stenosis of left anterior descending branch was 25.0% and 5.0% respectively, and that of the left circumflex branch was 7.5% and 3.9% respectively. The amount of chondroinn sulfate proteoglycan in the left anterior descending branch was 23.3 +/- 8.8% in intima and 12.0 +/- 4.0% in the media. The above findings suggest that the custom of eating large amounts of sea food may have a beneficial effect on lipid deposit, smooth muscle cell proliferation, thickness of intima and percentage of proteoglycan. Thus it is one of the important factors for the low incidence of coronary heart disease in this fishing region.

Adolescent↗
PubMed1996

[Effects of iodine and thyroid hormone deficiency during brain development on activities of cholinergic neurone-related enzymes in central nervous system of rats].

To study the effects of iodine and thyroid hormone deficiency during brain development on activities of enzymes of central acetyl choline metabolism, activities of choline acetylcholinetransferase (CHAT) and acetylcholinesterase (AChE) in hippocampus and cerebral cortex, basal forebrain and cerebellum in 20-day-old rats were determined. Results showed that CHAT and AChE activities in hippocampus, cerebral cortex and basal forebrain in iodine deficiency and hypothyroid rats were significantly lower than those in controls. A ratio of membranebound AChE to soluble AChE, activities of inextractable AChE, and percentage of its activities in the four sections of the brain in the trial rats were significantly lower, and activities of soluble AChE and its percentage of activities were significantly higher than those in controls. It suggests iodine and thyroid hormone deficiency could affect maturation of CHAT and disturb transformation and maturation of various molecular types of AChE and delay distinctly the development of cholinergic neurone during the critical period of brain development in rats.

Acetylcholinesterase↗
PubMed1996

[Analysis of cinnamic acid in storax and its original plant by HPLC].

The contents of free and hydrolytic cinnamic acid in storax and its original plant (Liquidambar orientalis) were determined by high performance liquid chromatography, and the chromatographic behaviors were studied. In styrax gummi, the contents of free and hydrolytic cinnamic acid were 7.03% and 25.26% respectively; and in its original plant, they were 0.3% evenly.

Chromatography, High Pressure Liquid↗
PubMed1995

Pharmacology of volume regulation following hypotonicity-induced cell swelling in clonal N1E115 neuroblastoma cells.

When exposed to hypotonic solutions, clonal N1E115 neuroblastoma cells initially swell and later undergo a regulatory volume decrease (RVD). We studied the effects of a variety of transport inhibitors on the time course of cross-sectional area of N1E115 cells exposed to a solution of reduced osmolarity (pi = 186 mosm). Application to the bath of either: (i) blockers of net K efflux through K channels (e.g. isotonic KCl or 20 mM TEA); or (ii) blockers of net efflux through anion channels (e.g. isotonic methanesulfonate, 10 microM DIDS or 100 microM IAA-94) all prevent RVD. In contrast, ouabain (a Na+/K+ pump blocker), bumetanide (a Na+/K+/Cl- cotransporter blocker) and SITS (a HCO3-/Cl- exchange blocker) do not. These data support the involvement of these channels over pumps or exchangers in solute exit during RVD. Only variable block of RVD was achieved using blockers of stretch activated non-selective cation C+ (SA) channels (i.e., amiloride and gadolinium, Gd3+) or a membrane permeant Ca chelator (BAPTA-AM) suggesting that neither the opening of C+ (SA) channels nor a global rise in cytosolic Ca2+ is critical for triggering RVD.

Animals↗
PubMed1995

Growth hormone improves cardiac performance in experimental heart failure.

BACKGROUND: Growth hormone has been shown to increase maximum isometric active force of the left ventricular papillary muscle of rats in vitro. Administration of growth hormone causes an increase in myocardial contractility in normal humans. Our preliminary study suggests that treatment with growth hormone results in increased ventricular contractility in rats with left ventricular dysfunction. In the present study, the effects of growth hormone on cardiac function, including cardiac output, stroke volume, and peripheral vascular resistance, were determined in a rat model of heart failure. METHODS AND RESULTS: Ligation of the left coronary artery or sham operation was performed; 4 weeks after surgery, recombinant human growth hormone (2 mg/kg per day SC) or vehicle then was administered for 15 days. The animals were catheterized after 13 days of the treatment. Cardiac output, measured by a thermodilution method, and other hemodynamic parameters were measured in the conscious animals 2 days after catheterization. The infarct sizes induced by left coronary ligation were comparable between growth hormone-treated and vehicle-treated rats. Six weeks after ligation, rats treated with vehicle exhibited significant decreases in cardiac index, stroke volume index, and left ventricular maximum dP/dt and increases in left ventricular end-diastolic pressure compared with sham rats. In the ligated rats, treatment with growth hormone increased cardiac index, stroke volume index, and left ventricular maximum dP/dt (P < .05) and reduced left ventricular end-diastolic pressure and systemic vascular resistance (P < .05). In sham rats, growth hormone slightly reduced arterial pressure but did not significantly alter cardiac performance. There was no significant difference in heart rate between the experimental groups. CONCLUSIONS: These results suggest that growth hormone treatment may improve cardiac function by both increased myocardial contractility and decreased peripheral vascular resistance in heart failure.

Animals↗
PubMed1995

Mutational effects on the p16INK4a tumor suppressor protein.

Several point mutations of p16INK4a were studied by site-specific mutagenesis and functional analysis to assess the effects of these mutations on the function of the protein. These mutations were reported in several malignancies. Three deletional mutants of p16INK4a were also analyzed to reveal the relationship between p16INK4a and p15INK4b and to test the importance of the ankyrin repeats observed in both proteins. We studied the activity of these mutants using the yeast two-hybrid system and an in vitro kinase assay. Our results suggest that point mutations in the conserved ankyrin consensus affect the activity of p16INK4a. However, not all of the point mutations observed in tumors have a detectable effect on the activity. The COOH-terminal region of p16INK4a is not required for the protein to bind and to inhibit CDK4, but the deletion of the 4th ankyrin repeat abolished the activity completely.

Amino Acid Sequence↗
PubMed1995

Characterization of an avian bone sialoprotein (BSP) cDNA: comparisons to mammalian BSP and identification of conserved structural domains.

Bone sialoprotein (BSP) is one of the major noncollagenous proteins found in mineralized vertebrate tissue. It is an acidic glycoprotein containing a high sialic acid content and is phosphorylated on several of its Ser and Thr residues. While it has been extensively characterized from various mammalian species, little is known about its sequence or expression in lower vertebrates. The cloning and characterization of several cDNAs encoding the chicken bone sialoprotein are reported here. A partial cDNA clone encoding the carboxyl terminus of the protein was initially isolated from a lambda GT11 expression library using a polyclonal antibody gains BSP purified from chicken bone matrix. Subsequently, several additional clones were obtained by further screening and by reverse transcription polymerase chain reaction (RT-PCR). Three overlapping clones encompassing about 1 kb, which included the complete coding sequence for BSP, were analyzed. The deduced amino acid sequence revealed that chicken BSP contains 276 amino acid residues. Although the overall identity between chicken and mammalian BSP is only approximately 39%, the diversity in amino acid sequence occurs mostly between the major functional domains of this molecule. These domains include: (1) three acidic poly-Glu regions; (2) two tyrosine-rich domains, which may be sites for protein sulfation; (3) several casein kinase II phosphorylation sites; (4) an Asn glycosylation site; and (5) an RGD cell-binding motif. Of interest in the chicken BSP is the identification of two additional RGD motifs within the avian sequence, unlike the mammalian forms of BSP which has only one.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

Effects of growth hormone in rats with postinfarction left ventricular dysfunction.

Growth hormone may affect cardiac function. In rats, chronic hypersecretion of growth hormone leads to increased maximum isometric contractile force of the left ventricular papillary muscle in vitro. In humans, administration of growth hormone can increase myocardial contractility. However, cardiac effects of growth hormone in heart failure or cardiac dysfunction have not been studied to date. The current study was to evaluate the cardiac effects of growth hormone in conscious rats with postinfarction left ventricular dysfunction and sham controls. Ligation of the left coronary artery or sham operation was performed, then 4 weeks after surgery, recombinant human growth hormone (2 mg/kg/day, SC) or vehicle was administered for 15 days. Catheters were implanted 13 days after treatment with growth hormone or vehicle. Hemodynamic parameters were measured in conscious rats 2 days after catheterization. In vehicle-treated rats, left ventricular systolic pressure, maximum dP/dt, and arterial pressure were significantly decreased and left ventricular end-diastolic pressure was significantly increased in the ligation group compared with sham controls. Growth hormone treatment increased left ventricular systolic pressure (p < 0.05) and dP/dt (p < 0.05) and reduced left ventricular end-diastolic pressure (p < 0.05), significantly in the ligated rats. In sham rats, growth hormone tended to decrease arterial pressure but did not alter ventricular contractility. Neither ligation nor growth hormone significantly altered heart rate and right atrial pressure. These results suggest that growth hormone treatment may improve cardiac function by increasing myocardial contractility in cardiac dysfunction or heart failure.

Analysis of Variance↗
PubMed1995

Preservation of postprandial intestinal hyperemic response after small bowel transplantation.

Postprandial intestinal hyperemia (PIH) is a normal physiological phenomenon and is thought to accommodate the increased intestinal metabolic demand during food digestion. Lack of such a response could lead to malabsorption. The purpose of this study was to determine whether transplanted intestine retains the ability to mediate PIH. Nineteen rats with syngeneic orthotopic small bowel transplantation (SBT) and 13 normal controls were further divided into two subgroups to receive gastric gavage of either 2 mL of Ensure Plus (EP) high-calorie liquid nutrition or 2 mL of normal saline. Intestinal blood flow was determined before, and 20 and 45 minutes after the gavage, employing a colored microsphere technique. The results showed that basal blood flow to the transplanted intestine (56.7 +/- 26.7 mL/min/100 g) was similar to that of normal intestine (64.2 +/- 35.8 mL/min/100 g; P > .1). EP feeding elicited a marked increase in intestinal blood flow (PIH phenomenon) in both normal and SBT animals. The magnitudes of flow increase were similar for the two groups (249 +/- 99% versus 241 +/- 76% of baseline 45 minutes after EP feeding in the normal and transplanted intestine, respectively; P > .1). The results indicate that hyperemic response to feeding is normal in syngeneic orthotopic SBT.

Animals↗
PubMed1995

Experimental liver cancer: improved response after hepatic artery ligation and infusion of tumor necrosis factor-alpha and interferon-gamma.

BACKGROUND: The aim of this study is to investigate whether regional infusion of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) could improve the therapeutic results of hepatic artery ligation (HAL) on liver cancer in a rat model. METHODS: Morris hepatoma 3924A was implanted intrahepatically in 50 ACI rats. Two weeks after tumor implantation, 40 rats underwent hepatic artery cannulation and ligation. The cannula was connected to an infusion port implanted subcutaneously. Animals were then divided into four groups of 10 each to receive seven daily intraarterial injections of IFN-gamma 100,000 IU/rat/day (HAL + IFN group), TNF-alpha 30 micrograms/rat/day (HAL + TNF group), IFN + TFN (HAL + IFN + TNF group), or normal saline solution (HAL group). The remaining 10 rats received a laparotomy only and served as untreated controls. Tumor volume, viable tumor area, and histopathology were assessed after 3 weeks. RESULTS: The tumor growth was significantly retarded in the HAL group compared with the controls (tumor volume 683 +/- 245 mm3 vs 2424 +/- 596 mm3, p < 0.05 ANOVA). HAL + TNF (221 +/- 93 mm3) and HAL + IFN + TNF groups (74 +/- 31 mm3), but not the HAL + IFN group (493 +/- 164 mm3), were much more effective than the HAL group in controlling tumor growth (p < 0.05). HAL + IFN + TNF achieved the best tumor control resulting in a 60% tumor-free rate (p < 0.05 vs all other groups). CONCLUSIONS: These data suggest that HAL combined with regional infusion of TNF-alpha and IFN-gamma significantly reduces tumor growth in a rat liver model. This attractive concept of combined modality therapy may have utility in the clinical setting in instances of unresectable liver cancer.

Animals↗
PubMed1995

Beneficial effects of growth hormone and insulin-like growth factor-1 in experimental heart failure in rats treated with chronic ACE inhibition.

The effects of growth hormone (GH) plus insulin-like growth factor-1 (IGF-1) were tested in an experimental model of cardiac failure treated with chronic angiotensin-converting enzyme (ACE) inhibition. Myocardial infarction was induced in rats by left coronary artery ligation. Two weeks after ligation, the animals received either captopril (2 g/L in drinking water) or water for 3 months. The rats were then given either GH (2 mg/kg/day) plus IGF-1 (2 mg/kg/day) or vehicle for 14 days. Captopril treatment decreased mean arterial pressure (MAP), left ventricular end-diastolic pressure (LVEDP) and systemic vascular resistance (SVR) (p < 0.05), and increased cardiac index (CI) and stroke volume index (SVI) (p < 0.05). GH/IGF-1 or captopril+GH/IGF-1 treatment decreased MAP, LVEDP, and SVR (p < 0.05), and increased left ventricular maximum dP/dt, CI, and SVI (p < 0.05). The increases in CI and SVI were significantly greater in the captopril+GH/IGF-1-treated animals than in those treated with captopril alone (p < 0.05). The beneficial effect of captopril in reducing cardiac hypertrophy was preserved in the captopril+GH/IGF-1 group. The results indicate that GH/IGF-1 and captopril can improve cardiac performance in congestive heart failure by independent and complementary mechanisms.

Angiotensin-Converting Enzyme Inhibitors↗