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Biomedical subjects

H Jin

Publications and source records attributed to H Jin.

At least 217 records · Page 12Linked to original sources
PubMed1994

The role of atrial natriuretic peptide and endothelin in hypoxia induced pulmonary hypertension.

The goal of our studies is to elucidate the role of atrial natrluretic peptide (ANP) and endothelin-1 (ET-1) and their receptor mechanisms in hypoxia-induced pulmonary hypertension and the control of pulmonary artery pressure in patients with pulmonary hypertension. Our experimental model is the male Sprague-Dawley rat subjected to normobaric hypoxia (10% O2, 1 atm) x 4 weeks or less. Our hypothesis is that ET-1 and ANP gene expression are enhanced by exposure to hypoxia and that the ET-1 and ANP so generated have causal and protective, respectively, effects on the development of hypoxia-induced pulmonary hypertension. Results from our studies demonstrated that ANP gene expression and ANP secretion in the heart, and the sensitivity to both endogenous and exogenous ANP in the pulmonary vasculature of hypoxia adapted rats are enhanced during hypoxic exposure. These data defined a role for ANP as a modulator hormone that protects against the development of acute hypoxic pulmonary vasoconstriction and chronic hypoxic pulmonary hypertension. Our studies also demonstrated that ET-1 and endothelin-A receptor (ET-AR) gene expression were selectively enhanced in the pulmonary vasculature by exposure to hypoxia, and that the ET-1 so generated is an important mediator in acute and chronic hypoxia-induced pulmonary hypertension. These results suggest that the intrapulmonary ET-1, acting on ET-AR receptors in the pulmonary vasculature mediates the hypoxia-induced pulmonary vasoconstriction and hypertension. In addition, our recent experiments have demonstrated that administration of BQ-123, a selective ET-AR antagonist, abolished the pulmonary vasoconstrictor response to acute (0-90 min) and chronic (2 weeks) hypoxia, further suggesting that ET-1 plays an important role in the pathogenesis of hypoxia-induced pulmonary hypertension in the rat. Results from our studies also indicate that selective ANP analogs and ET-AR antagonists may be clinically useful for the treatment of pulmonary hypertension.

Animals↗
PubMed1994

[Cloning of DNA fragments containing promoter activity from Streptomyces mycarofaciens 1748].

A DNA fragment containing promoter activity has been cloned from midecamycin producing strain (S. mycarofaciens 1748)., using promoter-probe plasmid vector pIJ486. The molecular size of this fragment was 2.3kb as shown by restriction analysis. A HindIII-HindIII 2.08KB DNA fragment obtained from the original fragment has been analysed by subcloning it into polylinker of vector pIJ486/7 which have opposite direction. The result showed that HindIII-HindIII 2.08kb DNA fragment has promoter activity in both direction. Transformants of plasmid containing this fragment in vector pIJ487 in S. lividans TK24 were resistant to Km in the level of 20mg/ml, but in vector pIJ 486 were resistant to the level of 3mg/ml. It indicated that a rather strong promoter activity region was in the HindIII/XbaI-HindIII direction. BamHI fragments (A-0.79kg, B-0.67kb, C-0.62kb) in 2.08kb DNA fragment have been studied in regards of their promoter activity. The result suggested that A-0.79kb region has the same promoter activity as in HindIII-HindIII 2.08kb DNA fragment.

Cloning, Molecular↗
PubMed1994

Simultaneous occurrence of adenomas in stomach, duodenal bulb, and colon: disappearance of gastric and duodenal adenomas during oral administration of 5'-deoxy-5-fluorouridine.

The present report concerns a patient who was first diagnosed as having adenoma in the duodenal bulb and subsequently was discovered to have adenomas in the stomach and colon. Surgical procedures including endoscopic resection could not be carried out because the patient had advanced liver cirrhosis. Follow-up colonoscopy no longer detected any polyp in the colon. Ultrasonography demonstrated a slowly growing hypoechoic mass in the liver, which was indicative of hepatocellular carcinoma. Then, single chemotherapy with oral administration of 5'-deoxy-5-fluorouridine was initiated. Surprisingly, repeated esophagogastroduodenoscopy revealed gradual regression of the gastric and duodenal tumors. Findings from the endoscopy and biopsy materials 10 months after the start of therapy showed disappearance of the gastric and duodenal adenomas. Despite enlargement of the hepatic mass, no recurrence of gastric and duodenal tumors has been noted during the past 1 1/2 yr.

Adenoma↗
PubMed1994

National field trial of the Chinese classification and diagnostic criteria of mental disorders: comprehensibility, acceptability and applicability.

The Chinese Neurology and Psychiatry Association conducted a national field trial of its Chinese Classification and Diagnostic Criteria of Mental Disorders (CCMD-2) involving 26 provinces and municipalities, 80 psychiatric institutes, and 224 professionals. The results were as follows: (1) 95.2% of researchers considered the comprehensibility of the CCMD-2 diagnostic criteria good. Within the ten major categories, comprehensibility ranged from 85.7% to 100%. (2) Of those surveyed concerning the acceptability of the CCMD-2 diagnostic criteria, 85.9% considered them acceptable. In individual classifications, the rate ranged from 74.1% to 95.2%. (3) 1498 cases were tested. The overall applicability rate which indicated the consistency between the CCMD-2 result and the actual clinical diagnoses was found to be 87.6%, (averaging Kappa = 0.82, P < 0.01), better than those obtained from non-Chinese systems of diagnosis.

Adult↗
PubMed1993

The involvement of ankyrin in the regulation of inositol 1,4,5-trisphosphate receptor-mediated internal Ca2+ release from Ca2+ storage vesicles in mouse T-lymphoma cells.

Mouse T-lymphoma cells contain a unique type of internal vesicle which bands at the relatively light density of 1.07 g/cc. These vesicles do not contain any detectable Golgi, endoplasmic reticulum, plasma membrane, or lysosomal marker protein activities. Binding of [3H]inositol 1,4,5-trisphosphate (IP3) to these internal vesicles reveals the presence of a single, high affinity class of IP3 receptor with a dissociation constant (Kd) of 1.6 +/- 0.3 nM. Using a panel of monoclonal and polyclonal antibodies against IP3 receptor, we have established that the IP3 receptor (approximately 260 kDa) displays immunological cross-reactivity with the rat brain IP3 receptor. Polymerase chain reaction analysis of first-strand cDNAs from both mouse T-lymphoma cells and rat brain tissues reveals that the IP3 receptor transcript in mouse T-lymphoma cells belongs to the short form (non-neuronal form) and not the long form (neuronal form) detected in rat brain tissue. Scatchard plot analysis shows that high affinity binding occurs between ankyrin and the IP3 receptor with a Kd of 0.2 nM. Most importantly, the binding of ankyrin to the light density vesicles significantly inhibits IP3 binding and IP3-induced internal Ca2+ release. These findings suggest that the cytoskeleton plays a pivotal role in the regulation of IP3 receptor-mediated internal Ca2+ release during lymphocyte activation.

Animals↗
PubMed1993

The involvement of the cytoskeleton in regulating IP3 receptor-mediated internal Ca2+ release in human blood platelets.

In this study we have used saponin to permeabilize platelet membranes in order to test directly the involvement of IP3 in regulating internal Ca2+ release, and to measure IP3 binding to its receptor. Our results indicate that platelet vesicles release Ca2+ as early as 3 seconds after IP3 addition. Using [3H]IP3, we have found that platelets contain a single class of high affinity IP3 binding sites with a Kd of approximately 0.20 (+/- 0.01) nM. Immuno-blotting shows that platelets contain a 260 kDa polypeptide which shares immunological cross reactivity with brain IP3 receptor. Immunofluorescence staining data indicate that the IP3 receptor is preferentially located at the periphery of the platelet plasma membrane. Most importantly, both IP3 binding and IP3-induced Ca2+ release activities are significantly inhibited by cytochalasin D (a microfilament inhibitor) and colchicine (a microtubule inhibitor). These findings suggest that the cytoskeleton is involved in the regulation of IP3 binding and IP3 receptor-mediated Ca2+ release during platelet activation.

Adult↗
PubMed1993

A physiological role of peptide YY on exocrine pancreatic secretion in rats.

BACKGROUND: Peptide YY (PYY) given intravenously was shown to inhibit pancreatic exocrine secretion both in the dog and the rat. However, a possible physiological role of PYY on the pancreatic secretion has not been clarified. The present study was undertaken to investigate its physiological role on the exocrine pancreas. METHODS: In conscious rats, plasma PYY was determined in response to oral ingestion of a 6-mL meal and intravenous infusion of PYY; small intestinal transit time was measured by phenol red as a nonabsorbable marker, and pancreatic secretory studies were performed in rats with pancreatic fistulas and jugular vein catheters. RESULTS: Oral ingestion of the meal (containing phenol red, 1.6 mg/100 mL) significantly increased plasma PYY within 30 minutes. During this period, most (97%) of the phenol red was detected in the proximal two-thirds of the small intestine. Intravenous infusion of PYY in 25, 50, and 100 pmol.kg-1 x h-1 produced a dose-dependent increase in plasma PYY. The dose of PYY that simulated the peak postprandial level was 50 pmol.kg-1 x h-1, and this dose of PYY significantly inhibited the pancreatic secretion stimulated by physiological doses of secretin and cholecystokinin-8 (CCK-8). After the meal, pancreatic secretion of bicarbonate and protein significantly increased in rats pretreated with normal rabbit serum, whereas this increase was significantly augmented in rats pretreated with an anti-PYY serum because the postprandial increase in plasma PYY was abolished. CONCLUSIONS: PYY plays a regulatory role in the postprandial pancreatic exocrine secretion in rats.

Animals↗
PubMed1993

Importance of tonicity of carbicarb on the functional and metabolic responses of the acidotic isolated heart.

In this study, the physiological and metabolic effects of Carbicarb administered as an isotonic (150 mmol/L Na[n[]I+) or hypertonic (1 mol/L Na[n[]I+) solution over 2 minutes in the acidotic isolated heart were compared. Physiological monitoring as well as 31P and 23Na nuclear magnetic resonance spectroscopy were performed. Both isotonic and hypertonic Carbicarb induced comparable dose-dependent increases in intracellular pH as well as decreases in inorganic phosphate and increases in creatine phosphate concentrations, which were sustained for 20 minutes. However, immediate functional improvement was greater in hearts receiving isotonic Carbicarb. Metabolic acidosis conditions resulted in a 27% increase in cytosolic sodium by 30 minutes (P < .05). In this setting, hypertonic Carbicarb induced a large transient increase in cytosolic sodium, whereas isotonic Carbicarb caused immediate and sustained decreases in cytosolic sodium. These data suggest that isotonic Carbicarb may have more beneficial effects on cardiac function than hypertonic Carbicarb. These effects may be related to associated changes in cytosolic sodium.

Acidosis↗
PubMed1993

Non-viral sequences at the 5' ends of Dugbe nairovirus S mRNAs.

Analyses of the mRNA transcription processes of viruses in four genera (Bunyavirus, Hantavirus, Phlebovirus and Tospovirus) of the family Bunyaviridae have revealed a common mechanism of initiation using host-derived primers, known as cap-snatching. To provide similar information on the fifth genus in the family, the 5' ends of Dugbe nairovirus S mRNA species were specifically cloned and sequenced. This revealed the presence of non-viral heterogeneous sequences, five to 16 nucleotides in length (average of 10 nucleotides) at the 5' ends, confirming that cap-snatching to prime mRNA synthesis is a familial characteristic of the Bunyaviridae. Inspection of the sequences in the primers on nairovirus, bunyavirus and phlebovirus mRNAs suggests that in some cases polymerase slippage occurs shortly after initiation, resulting in a partial reiteration of the 5'-terminal nucleotides of the viral RNA.

Base Sequence↗
PubMed1993

Autumn southward 'return' migration of the mosquito Culex tritaeniorhynchus in China.

Direct evidence for a southward 'return' migration in autumn of the mosquito Culex tritaeniorhynchus in China was obtained by aerial sampling with a net suspended from a balloon. In a preliminary study between 2 and 20 September 1990 at Jiangpu, near Nanjing, in Jiangsu Province, 11 females and 4 males of this species were taken at heights of 150-250 m. During 17-26 October 1991 at Dongxiang in northern Jiangxi Province, 44 mosquitoes (8 males, 36 females) were caught in the aerial net at heights of 80-380 m in northeasterly winds (E-NNW). Most of the specimens were flying within the subsiding air-mass behind a cold front. Cx tritaeniorhynchus was the only species identified (31 females) among the mosquitoes from Dongxiang. Of 24 females dissected, 17 had N stage ovaries--interpreted as diapause, five had stage I ovaries, one had stage II ovaries, and one was gravid (stage V), but none was freshly blood-fed. Cx tritaeniorhynchus is the main vector of Japanese viral encephalitis in China, and it is possible that the virus is reintroduced to northern temperate areas in spring by northward migration of infected Cx tritaeniorhynchus females.

Animals↗
PubMed1993

Characterization of Bunyamwera virus S RNA that is transcribed and replicated by the L protein expressed from recombinant vaccinia virus.

Analysis of the 5' termini of Bunyamwera virus S segment mRNAs by cloning and sequence analysis revealed the presence of nonviral, heterogeneous sequences 12 to 17 bases long. This is similar to reports for other members of the family Bunyaviridae and is taken to indicate that mRNA transcription is primed by a "cap-snatching" mechanism. The 3' end of the Bunyamwera virus S mRNA was mapped, by using an RNase protection assay, to 100 to 110 nucleotides upstream of the 3' end of the template. Previously we reported expression of the Bunyamwera virus L (polymerase) protein by recombinant vaccinia virus and demonstrated that the recombinant L protein was functional in terms of RNA synthesis activity in a nucleocapsid transfection assay (H. Jin and R. M. Elliott, J. Virol. 65: 4182-4189, 1991). In the present study we further analyze the RNAs made by using this system and show that positive-sense RNAs contain 5' nonviral sequences. Hence the initiation of mRNA transcription by the recombinant L protein resembles that seen during authentic bunyavirus infection and suggests that the L protein has the endonuclease activity which generates the primers. Some of these positive-sense transcripts terminated at the mRNA termination site, but the majority read through to the end of the template. No primer sequences were found at the 5' terminal of negative-sense RNAs. The recombinant L protein was able to replicate negative-sense RNA supplied by transfected virion-derived nucleocapsids, and both positive- and negative-sense RNAs were synthesized. These results indicate that the recombinant L protein has both transcriptase and replicase activities.

Base Sequence↗
PubMed1993

Immunocytochemical localization of substance P and neurofilament proteins in the guinea pig vestibular ganglion.

To examine the cytochemical features of primary vestibular afferent neurons, we examined the immunocytochemical distribution of substance P(SP) and neurofilament proteins (NFP) in the guinea pig vestibular endorgans and ganglion. 84.9% of vestibular ganglion cells showed SP-like immunoreactivity. SP immunoreactive cells were small in diameter (25.4 microns), and randomly distributed in the ganglia. NFP immunoreactive cells (34.2%) were relatively large in diameter (31.1 microns). By double-staining immunocytochemistry it was possible to distinguish three different cell types: SP-positive/NFP-negative, SP-negative/NFP-positive, and SP/NFP-positive vestibular ganglion cells. Vestibular ganglion cells can thus be classified on the basis of size and immunocytochemical characteristics. These chemically distinct subpopulations of vestibular ganglion cells may be an indication of functional differences within vestibular afferent neurons.

Animals↗
PubMed1993

Effect of the rice bran-derived phytosterol cycloartenol ferulic acid ester on the central nervous system.

In order to investigate the effect of cycloartenol ferulic acid ester (CFE, CAS 21238-33-5), a component of gamma-oryzanol which is a phytosterol derived from rice bran, on the central nervous system, a variety of pharmacological tests were performed. It was shown that CFE had a suppressant effect on the central nervous system, but its properties were different from those of existing major and minor tranquilizers. In addition, its efficacy in several models of cerebral dysfunction was demonstrated. Since any clear effects could not be obtained under the treatments with gamma-oryzanol, CFE seems to be more useful than gamma-oryzanol. Thus the results of this study suggest that CFE may serve as a new plant-derived cerebral activator possessing a wide range of pharmacological actions.

Amnesia↗
PubMed1993

Decreased synthesis and delayed processing of sulfated glycoproteins by cells from human polycystic kidneys.

BACKGROUND: In polycystic kidney disease, there is progressive distention of tubules and remodeling of an altered extracellular matrix. Recent findings indicate a defect(s) in the synthesis, post-translational modification, cellular transport, and extracellular matrix incorporation of proteoglycans in PKD that may have a fundamental role in its pathogenesis. EXPERIMENTAL DESIGN: Pulse-chase techniques and quantitative autoradiography were used to investigate in vitro the de novo synthesis and the kinetics of intracellular transport and extracellular matrix assembly of sulfated glycoproteins by epithelial cells from normal human kidneys (NK) and from cysts of autosomal dominant polycystic kidneys (ADPKD). NK and ADPKD cell monolayers were pulsed with [35S]sulfate for 150 min and chased for four intervals between 15 and 120 min. RESULTS: In ADPKD versus NK cells there was a significant reduction in the de novo synthesis of sulfated glycoproteins and, during the chase, a marked prolongation of the disappearance time for cellular sulfated glycoproteins. Transport kinetics revealed a substantial delay in processing and release of these macromolecules by the Golgi apparatus in ADPKD cells. During the chase, kinetics for the cellular transport of sulfated glycoproteins by secretory vesicles and their assembly into extracellular matrix were comparable in ADPKD and NK cells. However, the percentage of total sulfated glycoproteins incorporated into the matrix of ADPKD versus NK cell monolayers was notably diminished. CONCLUSIONS: The findings indicate that in ADPKD versus NK cell monolayers, synthesis of sulfated glycoproteins is impaired, processing of sulfated glycoproteins by the Golgi apparatus is prolonged, and assembly of these macromolecules into the extracellular matrix is reduced. These alterations may have a fundamental role in the pathogenesis of autosomal dominant polycystic kidney disease.

Autoradiography↗
PubMed1992

A single amino-acid difference confers major pharmacological variation between human and rodent 5-HT1B receptors.

Neuropsychiatric disorders such as anxiety, depression, migraine, vasospasm and epilepsy may involve different subtypes of the 5-hydroxytryptamine (5-HT) receptor. The 1B subtype, which has a unique pharmacology, was first identified in rodent brain. But a similar receptor could not be detected in human brain, suggesting the absence in man of a receptor with equivalent function. Recently a human receptor gene was isolated (designated 5-HT1B receptor, 5-HT1D beta receptor, or S12 receptor) which shares 93% identity of the deduced protein sequence with rodent 5-HT1B receptors. Although this receptor is identical to rodent 5-HT1B receptors in binding to 5-HT, it differs profoundly in binding to many drugs. Here we show that replacement of a single amino acid in the human receptor (threonine at residue 355) with a corresponding asparagine found in rodent 5-HT1B receptors renders the pharmacology of the receptors essentially identical. This demonstrates that the human gene does indeed encode a 1B receptor, which is likely to have the same biological functions as the rodent 5-HT1B receptor. In addition, these findings show that minute sequence differences between homologues of the same receptor from different species can cause large pharmacological variation. Thus, drug-receptor interactions should not be extrapolated from animal to human species without verification.

Alprenolol↗
PubMed1992

Characterization of the human 5-hydroxytryptamine1B receptor.

We report the cloning of a human gene encoding the 5-hydroxytryptamine1B receptor. The receptor has the characteristics of a G-protein-linked receptor and is most homologous to the human 5-HT1D receptor. This human 5-HT receptor gene, most abundantly expressed in striatum, is localized on chromosome 6, at 6q13, and the gene encoding the 5-HT1D receptor is localized on chromosome 1. Radioligand studies indicate that the affinity of [3H]5-HT is 16 +/- 2 nM. Drug competition studies indicate that the receptor displays high affinity (i.e. less than 40 nM) for 5-HT, 5-carboxyamidotryptamine, methiothepin, and metergoline.

Amino Acid Sequence↗
PubMed1992

Comparative observation of the changes in serum lipid peroxides influenced by the supplementation of vitamin E in burn patients and healthy controls.

A microfluorescence analytical method was used to determine the contents of serum lipid peroxides and vitamin E in 35 severely burned patients, among whom 18 had been given vitamin E, and in 113 healthy blood donors. A comparative survey showed that the serum vitamin E decreased most significantly from days 6 to 8 postburn in both groups of burned patients, while the concomitant serum lipid peroxides increased significantly and reached a peak value. In control patients, the serum vitamin E levels were lower and lipid peroxides higher than those of healthy people (P less than 0.05) from days 20 to 22 postburn. At this time in the vitamin E-treated patients, the serum vitamin E levels increased and lipid peroxides decreased to the levels of healthy people (P greater than 0.05). Therefore, appropriate supplementation with vitamin E in burn patients is necessary.

Adolescent↗