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Biomedical subjects

X Jin

Publications and source records attributed to X Jin.

At least 145 records · Page 8Linked to original sources
PubMed1997

[Clinical observation on 206 cases with lower limb deep venous thrombosis treated by integrated traditional Chinese and Western medicine].

OBJECTIVE: To study the pathogenetic mechanism of lower limb deep venous thrombosis (DVT). METHODS: Thrombosis test in vitro of 206 cases with lower limb DVT was measured. All of them were treated by integrated traditional Chinese and Western medicine (TCM-WM). RESULTS: The indexes of thrombosis test in vitro of patients were much higher than those of normal subjects (P < 0.001). The relevent indexes were different in types distribution according to differentiation of symptoms and signs (P < 0.01-0.001) and between before and after treatment (P < 0.001). It showed that hypercoagulability of blood occurred even if after the occurence of DVT. Changes of indexes might be objective parameters for Syndrome Differentiation in TCM. The indexes became lower when state of illness was improving. CONCLUSION: The therapy of TCM-WM has good efficacy for DVT.

Adult↗
PubMed1996

Factors accounting for different responses of pulmonary and cerebral vessels to hypoxia.

The roles of sympathicus, sensory neuropeptides (SNP), cyclooxygenase metabolites (COX-M), lipoxygenase metabolites (LOX-M), endothelium derived relaxing factor (EDRF), reactive oxygen (ROS) and potassium channels (PC) in the hypoxic pulmonary vasoconstriction (HPV) and hypoxic cerebral vasodilation (HCVD) were investigated in intact rats, rabbits and dogs. The results showed that during hypoxia, the excitation of sympathicus caused a constriction of both pulmonary and cerebral vessels, while SNP, EDRF and the opening of voltage sensitive PC caused the dilation of both of them; LOX-M mediated HPV and HCVD, COX-M might serve as their modulators; the blockade of ATP sensitive PC induced by hypoxia mediated HPV, but had no effect on HCVD; the reduction of O2-. in the lung might potentiate HPV, however, O2-. remained unchanged in brain during hypoxia. It is suggested that the alterations of LOX-M, ROS and the ATP sensitive PC are the factors accounting for the difference in the response of pulmonary and cerebral vessels to hypoxia.

Animals↗
PubMed1996

The human cytotoxic T-lymphocyte (CTL) response to cytomegalovirus is dominated by structural protein pp65: frequency, specificity, and T-cell receptor usage of pp65-specific CTL.

Cytotoxic T lymphocytes (CTL) appear to play an important role in the control of human cytomegalovirus (HCMV) in the normal virus carrier: previous studies have identified peripheral blood CD8+ CTL specific for the HCMV major immediate-early gene product (IE1) and more recently, by bulk culture and cloning techniques, have identified CTL specific for a structural gene product, the lower matrix protein pp65. In order to determine the relative contributions of CTL which recognize the HCMV proteins IE1, pp65, and glycoprotein B (gB) to the total HCMV-specific CTL response, we have used a limiting-dilution analysis system to quantify HCMV-specific CTL precursors with different specificities, allowing the antigenic specificity of multiple short-term CTL clones to be assessed, in a group of six healthy seropositive donors. All donors showed high frequencies of HCMV-specific major histocompatibility complex-restricted CTL precursors. There was a very high frequency of CTL specific for pp65 (lower matrix protein); IE1-specific CTL were also detectable at lower frequencies in three of five donors, while CTL directed to gB were undetectable. A pp65 gene deletion mutant of HCMV was then used to estimate the contribution of pp65-specific CTL to the total HCMV-specific CTL response; this showed that between 70 and 90% of all CTL recognizing HCMV-infected cells were pp65 specific. Analysis of the peptide specificity of pp65-specific CTL showed that some donors have a highly focused response recognizing a single peptide; the T-cell receptor Vbeta gene usage in these two donors was shown to be remarkably restricted, with over half of the responding CD8+ T cells utilizing a single Vbeta gene rearrangement. Other subjects recognized multiple pp65 peptides: nine new pp65 CTL peptide epitopes were defined, and for five of these the HLA-presenting allele has been identified. All four of the HLA A2 donors tested in this study recognized the same peptide. This apparent domination of the CTL response to HCMV during persistent infection by a single structural protein, irrespective of major histocompatibility complex haplotype, is not clearly described for other persistent virus infections, and the mechanism requires further investigation.

Amino Acid Sequence↗
PubMed1996

Analysis of the human env-specific cytotoxic T-lymphocyte (CTL) response in natural human immunodeficiency virus type 1 infection: low prevalence of broadly cross-reactive env-specific CTL.

Major histocompatibility complex-restricted cytotoxic T lymphocytes (CTL) are part of the cellular immune response to persistent virus infections. Candidate vaccines against human immunodeficiency virus type 1 (HIV-1) should elicit broad cross-reactive immunity to confer protection against different strains of HIV-1. As it is likely that candidate vaccines will include the envelope gene product Env, we determined the proportion of CTL clones which recognized variable and conserved determinants in three env variants during natural infection. Limiting dilution analysis was used to characterize numerous short-term CTL clones derived from peripheral blood of HIV-1-infected subjects, using split-well analysis to assay cytotoxicity against target cells expressing gp160env of HIV-1 strains IIIB, MN, and RF. In 9 of 12 HIV-1-infected subjects, at the clonal level most env-specific CTL recognized determinant(s) within one env variant but not in the other variants. In some subjects, CTL recognized multiple nonconserved determinants in different variants. The pattern of recognition of different env variants was relatively stable over time. In most of the patients studied, the proportion of CTL which showed cross-recognition of conserved determinants shared among the three strains was low. Two novel CTL epitopes within gp41 were identified by using 15-mer peptides of the HIV-SF2 sequence. When specific peptide was used to stimulate CTL precursors in vitro, the frequency of peptide-specific CTL precursors was very high, but the CTL elicited by this stimulation were highly strain specific. We conclude that the use of a single HIV env variant to detect CTL activity can underestimate the magnitude and complexity of the env-specific CTL response. The low prevalence of CTL clones which show cross-recognition of conserved determinants may have implications for immunization strategies based solely on env; to elicit broadly cross-reactive CTL other, more conserved viral antigens are likely to be needed in addition to env. Because of its capacity to distinguish CTL responses against different virus strains, limiting dilution analysis is particularly appropriate to quantitate the immune responses generated by candidate env-based vaccines.

Adult↗
PubMed1996

[Role of sensory neuropeptides in the responses of pulmonary and cerebral blood vessels to acute hypoxia in rats].

OBJECTIVE: To study the effects of sensory neuropeptides on pulmonary circulation and cerebral blood flow during acute hypoxia in SD rats. METHODS: The changes in hypoxic pulmonary vasoconstriction (HPV) and hypoxic cerebral vasodilatation (HCVD) were observed in mature SD rats pretreated with capsaicin (50 mg/kg) when they were newborn. The hypoxic changes of plasma substance P in the pulmonary circulation and the peptidergic nerve fibers in the lungs were determined with radioimmunoassay and immunohistochemical staining respectively. The effects of exogenous SP on HPV and HCVD were studied as well. RESULTS: The mean pulmonary artery pressure (2.46 +/- 0.07kPa), pulmonary vascular resistance (3665.09 +/- 164.08kPa.s/L) and the percentage change of pulmonary vascular resistance (delta PVR%) during hypoxia (98.67% +/- 4.07%) in group capsaicin (Caps) were higher than those in group Veh (vehicle control) (2.22 +/- 0.04 kPa, 2945.14 +/- 119.23kPa.s/L and 41.21% +/- 2.08% respectively) (t = 2.89, 3.49 and 12.18, P < 0.01) and those in group NC (normal control) (2.22 +/- 0.03 kPa, 2908.19 +/- 130.85 kPa.s/L and 39.13% +/- 1.48%) (t = 3.09, 3.59 and 13.48, P < 0.01). The wave amplitude in rheoencephalogram (H) in group Caps (11.27 +/- 1.02 m omega) was less than those in group Veh (14.96 +/- 1.08 m omega) (t = 2.49, P < 0.05) and group NC (15.86 +/- 1.33 m omega) (t = 2.69, P < 0.05) during normoxia. It increased significantly in groups Veh (41.36% +/- 6.74%) (t = 9.44, P < 0.01) and NC (48.79 +/- 6.10%) (t = 11.21, P < 0.01) during acute hypoxia, however it dropped in group Caps (-23.55 +/- 2.38%). The plasma SP-like immunoreactivity level in the outflow blood of pulmonary circulation increased in hypoxic rats (SPop-SPip = 139.04 +/- 27.97 pmol/L) while it decreased in group Caps (SPop-SPip = -45.84 +/- 6.52 pmol/L) (t = 5.41, P < 0.01). The SP- and CGRP-immunoreactive fibers in lungs appeared to be sparser and thinner during hypoxic inspiration for 3-5 min. SP decreased delta PVR% from 47.42% +/- 4.70% to 20.58% +/- 2.66% (t = 6.84, P < 0.01) while it increased delta H% from 12.51% +/- 4.31% to 37.66% +/- 5.17% (t = 3.93, P < 0.01) during hypoxia. CONCLUSIONS: Sensory neuropeptides might contribute to the modulation of the basic tone of pulmonary and cerebral vessels. They could be released during acute hypoxia modulating HPV and mediating HCVD.

Animals↗
PubMed1996

[The epidemiological and clinical features of 208 patients with trichinosis].

In order to know the epidemiological and clinical features of trichinosis, the data of 208 patients with trichinosis from 1992 to 1994 were analysed. The results showed that these patients came from 11 districts, and acquired the infection mainly by tasting the raw pork filling for dumplings or ingesting instant-boiled pork or mutton. The incidence of trichinosis is high in winter. Young and middle-aged workers and cadres constituted the majority of the patients and the infection was more common in the males than in females. The main clinical manifestations of trichinosis were prolonged fever, general myalgia, muscle weekness and eosinophilia. Most of the patients had no gastrointestinal symptoms and skin eruption. Eyelid edema was only seen in the early stage. Serological tests were significant value in the diagnosis of trichinosis. The key measures to prevent trichinosis were that meat inspection should be strictly carried out and bad eating habit changed.

Adolescent↗
PubMed1996

[The role of hypergastrinemia in the pathogenesis of intussusception in infants].

From 1988 to 1992 the serum gastrin levels of 124 patients with intussusception and 20 normal infants and 15 patients with intestinal obstruction under 3 years of age were measured. Serum cAMP levels of 10 normal infants and 10 patients with intussusception were determined. In animal experiment study, the pressures of ileum cavity and ileoceal valve were determined before and after injectting pentagastrin into the veins of 8 young dogs. The levels of gastrin (219.9 +/- 100.6 pg/ml) and cAMP (32.4 +/- 7.6 pmol/ml) were higher in patient group than in the control group. (89 +/- 3 pg/ml, P < 0.05 and 22.2 +/- 7.5 pmol/ml P < 0.05). The result of animal experiment showed that the effect of gastrin and etiology of intussusception are identical. The main physiological funcitons of gastrin is to increase the intestinal peristalsis and relax the ileocecal sphincter. Our study showed that hypergastrinemia may be the basis etiologic factor of intussusception. Main clinical feactures were explained by this new theory.

Animals↗
PubMed1996

[The trend of changes in etiologic types of heart diseases in Shanghai from 1948 to 1989].

Analysis of the data from 7188 cases seen in the 1980s two general hospitals in Shanghai and comparison of the data with those in the 1950s, 1960s and 1970s revealed that the percentage of heart diseases among the inpatients in medical wards increased in each decades, from 9.89%, 15.69% 20.91% to 23.54% respectively. The constituent ratios of different etiologic types of heart diseases changed. Coronary heart disease constituted the largest proportion, next in number was rheumatic heart disease and congenital heart disease was in the third place. The incidence of congenital heart diseases, myocarditis, cardiac dysrhythmias without organic heart diseases, cardiomyopathy and endocarditis increased and that of rheumatic heart disease, pulmonary heart disease and hypertensive heart disease apparently decreased, syphilitic heart disease was rarely encountered.

Adolescent↗
PubMed1995

Stopped-flow kinetic study of the reaction of ascorbic acid with peroxynitrite.

A new mechanism is presented for the oxidation of ascorbate by peroxynitrite. Our mechanism involves the reaction of ascorbate both with ground-state peroxynitrous acid (HOONO) and with a reactive intermediate (HOONO*); the reactive intermediate is postulated to be formed in the decay of HOONO to form nitrate. At physiological pH, the ascorbate monoanion (AH-) is the predominant ascorbate species. The plot of the observed rate constant for peroxynitrite decay (kobs) vs AH- for the reaction of peroxynitrite with AH- shows two regions, one linear and one curved. In the linear region, which involves high AH- concentrations, the reaction is dominated by the bimolecular reaction between HOONO and AH-. At lower AH- concentrations, this bimolecular reaction slows and reactions with both HOONO and HOONO* produce the observed curvature. Analysis of the data leads to the estimation of the ratio of rate constants for the reaction of AH- with HOONO* (k2*) and the decay of HOONO to nitrate (kN), giving the value of k2*/kN = 3158 +/- 505 M-1; and of the rate constant (k2) for the reaction between AH- and HOONO, k2 = 236 +/- 14 M-1 s-1. Ascorbate displays higher selectivity for HOONO* than does methionine or 2-keto-4-thiomethylbutanoic acid, two substrates whose reactivity toward HOONO and HOONO* has previously been reported. The biological relevance of the reaction of ascorbate with peroxynitrite is discussed in terms of the rate constants and the concentrations of AH- typically found in biological systems; ascorbate may react with HOONO*, although the reaction with ground-state HOONO probably is too slow to occur in vivo.

Ascorbic Acid↗
PubMed1995

Cell cycle arrest and inhibition of tumor cell proliferation by the p16INK4 gene mediated by an adenovirus vector.

The p16INK4 (MTS1) gene has many features of a tumor suppressor gene. It maps to 9p21, a region of frequent loss of heterozygosity in a variety of tumor types. It encodes an inhibitor of cyclin-dependent kinase 4, and its homozygous deletion is common in tumor-derived cell lines. To examine its tumor suppressive function and its potential in cancer gene replacement therapy, wild-type p16INK4 was expressed in an adenovirus-derived gene delivery system and introduced into lung cancer cell lines that do not express p16INK4. Expression of the introduced p16INK4 blocked tumor cell entry into S phase of the cell cycle and inhibited tumor proliferation both in vitro and in vivo. These observations strongly support that p16INK4 is a tumor suppressor gene and is a candidate for cancer gene replacement therapy.

Adenoviridae↗