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Biomedical subjects

S Jin

Publications and source records attributed to S Jin.

At least 181 records · Page 10Linked to original sources
PubMed1997

[The changes of plasma endothelin concentration and its clinical significance in pulmonary hypertension associated with congenital heart defects].

Plasma endothelin (ET) concentration was measured by means of radioimmunoassay in 38 patients with congeital heart defects among whom 15 patients with pulmonary hypertension (PH) and 23 patients without pulmonary hypertension (non-PH). Blood samples were obtained separately from the femoral vein, right atrium, right ventricle, main pulmonary artery and the femoral artery during catherization. Plasma ET concentration in the PH group was significantly higher than that in the non-PH group at all four sampling sites. In the PH group plasma ET concentration in the pulmonary artery showed higher than that of the right ventricle and the femoral artery, which was significantly in positive correlation with pulmonary artery pressure. It is considered that the elevation of ET plays an important physiological role in the formation of pulmonary hypertension.

Adolescent↗
PubMed1997

[Measurements of serum and subretinal fluid before and after surgery of retinal detachment].

OBJECTIVES: To investigate the relationships between proliferative vitreoretinopathy (PVR) formation and the levels of human epidermal growth factor (h-EGF) and tumor necrosis factor (TNF) in serum and subretinal fluid (SRF) before and after surgery of retinal detachment with PVR. METHODS: Serum and SRF samples of 51 patients with retinal detachment and PVR were collected, and their h-EGF and TNF levels were measured by radioimmunoassays. RESULTS: In comparison with the control group, the levels of h-EGF and TNF in serum and SRF in retinal detachment with PVR group were higher but not statistically significant (P > 0.05). Their levels in the serum were not related to the severity of the disease, while their levels in SRF increased significantly with the increase of the severity of the disease, and these two factors were positively correlated (P < 0.05). 5 days after the surgery of retinal detachment, the h-EGF and TNF levels in serum increased significantly (P < 0.01) and the levels decreased within 30 days but not to normal. CONCLUSIONS: The h-EGF and TNF in SRF might have a synergic action and affect the formation and development of PVR. The h-EGF and TNF in serum take part in the repair of the operative trauma and inflammatory reaction. However, their high levels could interfere with the effect of operation.

Adult↗
PubMed1997

Changes on receptor expression and production of interleukin-2 in circulating lymphocyte population after open heart surgery.

To evaluate the change of perioperative cell mediated immunity after cardiac operation with cardiopulmonary bypass (CPB), so as to provide some information for timely prevention and treatment against postoperative immunological disorder, 40 patients were studied. By searching for the effects of CPB and anesthesia, interleukin-2 receptor (IL-2R) expression upon the surface of peripheral blood mononuclear cells (PBMC), as well as interleukin-2 (IL-2) production in vitro was traced 55 min after anesthesia, at end of CPB, on postoperative 1, 7, and 14 day versus preanesthesia control. Our data demonstrated that expression of IL-2R on PBMC was significantly suppressed in all comparing with the baseline value, meanwhile, IL-2 production in vitro also statistically dropped. However, no statistical difference was found on perioperative IL-2R expression and IL-2 synthesis in the cholecystectomy group. We conclude that postoperative immunological disorder seems to be the main factor, which could be denoted as reduced IL-2R expression on PBMC and IL-2 synthesis in vitro for sepsis, even multiple system organ failure developed after cardiac surgery.

Adolescent↗
PubMed1997

The Spanish Instrument Protocol: design and implementation of a study to evaluate treatment efficacy Instruments for Spanish-speaking patients with Alzheimer's disease. The Alzheimer's Disease Cooperative Study.

Development of improved outcome measures for Alzheimer's disease (AD) clinical trials is a major objective of the Alzheimer's Disease Cooperative Study (ADCS), an NIA-sponsored, multisite clinical trials consortium. The ADCS is committed to recruiting and following minority patients in clinical trials. At present, a serious impediment to recruiting non-English-speaking minorities is the lack of instruments with adequate translation. Because Spanish is the second most commonly spoken language in the United States and because persons of Hispanic origin represent approximately 10% of the population, we conducted an instrument development protocol for Spanish-speaking patients. Evaluating treatment efficacy in Spanish-speaking AD patients requires the development of assessments that are comparable to those used for English-speaking participants in clinical trials. The ADCS Instrument Development Project evaluated the sensitivity, reliability, and validity of new or improved measures in each of five assessment domains: (a) cognition (immediate and delayed memory, praxis, attention, and executive function); (b) clinical global change; (c) activities of daily living; (d) behavioral symptoms (agitation and other noncognitive symptoms); and (e) cognition in severely impaired patients. These new treatment efficacy instruments were translated for Spanish speakers and a Spanish Instrument Study was conducted in parallel with the English version of the study. This report describes instrument translation, entry criteria, and recruitment procedures. In addition, the demographic and clinical characteristics of the cohort at baseline are presented and compared to the English-speaking cohort. Implications for the development of comparably sensitive Spanish language instruments are discussed.

Aged↗
PubMed1997

Functions of the DNA dependent protein kinase.

The DNA dependent protein kinase (DNA-PK) is a trimeric nuclear complex consisting of a large protein kinase and the Ku heterodimer that regulates kinase activity by its association with DNA. Recent findings have shown structural similarities between DNA-PK and a family of lipid and putative protein kinases (PIK family). DNA-PK is one of the PIK members known to be a protein kinase with clearly identified effector subunits. A broad range of observations link DNA-PK to dual roles in double strand DNA break (DSB) repair and transcription. Unlike its most closely related PIKs, DNA-PK is not required for activating cell cycle regulated DNA damage signalling mechanisms. Instead, the phenotypes and biochemical properties of DNA-PK are most consistent with functions in DSB repair and joining steps in recombination mechanisms. DNA-PK is associated with RNA polymerase II and RNA polymerase I transcription complexes, where it most frequently has a negative regulatory role.

Animals↗
PubMed1997

[Trends and changes in antimicrobial resistance of clinical isolates from 11 hospitals in Beijing area].

OBJECTIVE: To study the antimicrobial resistance and its changes of clinical isolates in Beijing area. METHODS: The diameters of the inhibition zones of clinical isolates around antibiotic susceptibility test discs at 12 hospitals in Beijing area were computerfiled and analysed by the software of 'WHONET' according to NCCLS published in 1994. RESULTS: A total of 10,305 isolates were collected in 1995. The percentages of resistance were as follows: (1) in E. coli: amikacin, 8%, ceftazidime, 15%, the other third generation cephalosporins, about 30%, (2) in Klebsiella spp: ofloxacin, 0%, ceftazidime, 15%, ciprofloxacin, 17%, norfloxacin, 15%, ofloxacin, 5%, (4) in Staph. aureus: norvancomycin, 0%, (5) in Strep. pneumoniae: penicillin G, 9%, (6) in Enterococcus spp: norvancomycin, 7%. The antimicrobial resistant changes over a six year period from 1990 to 1995 were surveyed and it was found that resistant percentage of the most isolates to quinolones, for example norfloxacin, increased significantly year by year and no remarkable differences of resistance to antimicrobial agents but quinolones were observed in Ps. aeruginosa. CONCLUSION: Antimicrobial resistance should be emphasised during clinical therapy with antimicrobial agents, and trends in antimicrobial resistance of isolates should be followed.

Anti-Infective Agents↗
PubMed1996

The sensing of plant signal molecules by Agrobacterium: genetic evidence for direct recognition of phenolic inducers by the VirA protein.

The virulence (vir) genes of Agrobacterium tumefaciens are induced by low-molecular-weight phenolic compounds and monosaccharides through a two-component regulatory system consisting of the VirA and VirG proteins. Although it is clear that the monosaccharides require binding to a periplasmic binding protein before they can interact with the sensor VirA protein, it is not certain whether the phenolic compounds also interact with a binding protein or directly interact with the sensor protein. To shed light on this question, we tested the vir-inducing abilities of several different phenolic compounds using two wild-type strains of A. tumefaciens, KU12 and A6. We found that several compounds such as 4-hydroxyacetophone and p-coumaric acid induced the vir of KU12, but not A6. On the other hand, acetosyringone and several other phenolic compounds induced the vir of A6, but not KU12. By transferring different Ti plasmids into isogenic chromosomal backgrounds, we showed that the phenolic sensing determinant is associated with the Ti plasmid. Subcloning of the Ti plasmid indicated that the virA locus determines which phenolic compounds can function as vir inducers. These results suggest that VirA directly senses the phenolic compounds for vir activation.

Agrobacterium tumefaciens↗
PubMed1996

Large-scale isolation of candidate virulence genes of Pseudomonas aeruginosa by in vivo selection.

Pseudomonas aeruginosa, an opportunistic human pathogen, is a major causative agent of mortality and morbidity in immunocompromised patients and those with cystic fibrosis genetic disease. To identify new virulence genes of P. aeruginosa, a selection system was developed based on the in vivo expression technology (IVET) that was first reported in Salmonella system. An adenine-requiring auxotrophic mutant strain of P. aeruginosa was isolated and found avirulent on neutropenic mice. A DNA fragment that can complement the mutant strain, containing purEK operon that is required for de novo biosynthesis of purine, was sequenced and used in the IVET vector construction. By applying the IVET selection system to a neutropenic mouse infection model, genetic loci that are specifically induced in vivo were identified. Twenty-two such loci were partially sequenced and analyzed. One of them was a well-studied virulence factor, pyochelin receptor (FptA), that is involved in iron acquisition. Fifteen showed significant homology to reported sequences in GenBank, while the remaining six did not. One locus, designated np20, encodes an open reading frame that shares amino acid sequence homology to transcriptional regulators, especially to the ferric uptake regulator (Fur) proteins of other bacteria. An insertional np20 null mutant strain of P. aeruginosa did not show a growth defect on laboratory media; however, its virulence on neutropenic mice was significantly reduced compared with that of a wild-type parent strain, demonstrating the importance of the np20 locus in the bacterial virulence. The successful isolation of genetic loci that affect bacterial virulence demonstrates the utility of the IVET system in identification of new virulence genes of P. aeruginosa.

Amino Acid Sequence↗
PubMed1996

Inhibition of Serratia marcescens nuclease secretion by a truncated nuclease peptide.

The production of extracellular nuclease (Nuc) from the Serratia marcescens nucA chromosomal locus is inhibited in cells producing the N-terminal portion of Nuc from a multicopy plasmid. This inhibition in trans is not at the level of nucA expression, but rather at the level of secretion of the Nuc protein. Production of the periplasmic protein beta-lactamase (Bla) does not inhibit Nuc production unless fused to the nucA signal peptide and expressed from nucAp. Inhibition by either the truncated Nuc peptide (delta Nuc) or a Bla fusion protein is promoter specific and observed when expressed from nucAp; little inhibition is observed when the same protein is expressed from the lacZpo promoter-operator. This promoter specificity is also true for the secretion of Nuc itself.

Endodeoxyribonucleases↗
PubMed1996

Regulation of the Serratia marcescens extracellular nuclease: positive control by a homolog of P2 Ogr encoded by a cryptic prophage.

The Serratia marcescens extracellular nuclease is a secreted protein that is subject to growth phase and SOS control. Regulatory mutants affecting nuclease expression have been isolated that define a new locus, nucC, essential for transcription of the nuclease gene nucA. The cloned nucC gene is able to activate efficient expression from the nucA promoter in Escherichia coli, where it normally is poorly expressed. NucC is very similar to the bacteriophage P2 Ogr protein, a transcriptional activator essential for P2 late gene expression. NucC is able to replace P2 Ogr to support the growth of P2 ogr- mutants in E. coli. Ogr is a poor activator of the nuclease promoter in E. coli, but the related delta gene product from satellite phage P4 is highly effective. The presence of genes encoding a lysozyme and a putative porin or holin in the nucC operon suggests that nucC may be part of a cryptic prophage genome. The putative holin-like membrane protein is required in E. coli for extracellular secretion of the S. marcescens nuclease.

Amino Acid Sequence↗
PubMed1996

Isolation and characterization of Pseudomonas aeruginosa genes inducible by respiratory mucus derived from cystic fibrosis patients.

Pseudomonas aeruginosa, an opportunistic human pathogen, is a major causative agent of mortality and morbidity in immunocompromised individuals and those with cystic fibrosis (CF). In CF patients, the secretion of abnormally high amounts of mucus into the airways contributes to their susceptibility to infection by P. aeruginosa. To identify virulence genes of P. aeruginosa that are important in infection of CF patients, an in vivo selection system (IVET) was used to identify promoters that are specifically inducible by respiratory mucus derived from CF patients. Three genetic loci that are highly inducible by the mucus were identified. One of them is a well-characterized virulence gene (fptA), encoding the receptor for pyochelin, which is a P. aeruginosa iron siderophore. Induction of the fptA gene by mucus is suppressed by the addition of exogenous iron, demonstrating that the mucus is an iron chelator and generates an iron-deficient environment in CF lungs. Therefore, as a part of the host-defence mechanism, the mucus could also be responsible for induction of iron-regulated virulence factors of bacterial pathogens. The second locus, np20, encodes a peptide that shares sequence homology to a number of transcriptional regulators. An identical locus was previously identified to be inducible in vivo during infection of mice and was shown to be important in bacterial virulence in a neutropenic-mouse infection model. The third locus, designated migA (mucus inducible gene), was sequenced and found to encode a 299-amino-acid peptide which is homologous to glycosyltransferases of other bacteria, and is involved in the biosynthesis of lipopolysaccharides or exopolysaccharides. Inducibilities of the np20 and migA genes are not affected by iron and the exact nature of the inducing signals in the mucus is not known. The possible implications of the migA inducibility by respiratory mucus is discussed in relation to the P. aeruginosa infection in CF.

Amino Acid Sequence↗
PubMed1996

Release of adenosine from rat hippocampal slices by nitric oxide donors.

In the present study we have used perfused hippocampal slices to examine the hypothesis that nitric oxide (NO) can evoke the release of adenosine from nervous tissue. ATP stores were labeled by incubation with [3H]adenine. Electrical field stimulation at 5 Hz for 5 min evoked the release of 3H-purines, and this was enhanced by the NO donor S-nitroso-N-acetylpenicillamine (SNAP). Stimulation at 10 Hz for 15 min evoked a larger release of 3H-purines, which was enhanced in a concentration-dependent manner by both SNAP and sodium nitroprusside (SNP), with SNP being 100-fold less potent than SNAP. N-Acetylpenicillamine (N-AP) was without effect. SNAP had a markedly reduced, although significant, effect when given in the absence of field stimulation. Using HPLC it was found that SNAP enhanced the release of both endogenous and labeled adenosine in a concentration-dependent manner. At the highest concentration used (1 mM), SNAP increased electrically evoked release of endogenous adenosine 100-fold and unstimulated adenosine release eightfold. The ability of SNAP to enhance adenosine release was eliminated in the added presence of hemoglobin (10 microM), further supporting the proposal that the effects of SNAP were due to the liberation of NO. These data provide direct evidence that NO evokes a concentration-dependent release of adenosine from both stimulated and unstimulated nerves of the hippocampus. It is suggested that such NO-stimulated adenosine release may contribute to some of the reported effects of NO donors in the nervous system.

Adenosine↗
PubMed1996

The epidemiology of rotavirus diarrhea in the United States: surveillance and estimates of disease burden.

The decision to develop rotavirus vaccines was predicated on the extensive burden of rotavirus disease among children worldwide. US reports on nationwide hospitalizations (1979-1992) and deaths (1968-1991) due to diarrhea and weekly reports of rotavirus infection by 74 laboratories were reviewed to estimate the burden of rotavirus disease, identify epidemiologic trends, and consider methods for evaluating an immunization program when a vaccine becomes available. From 1968 to 1985, diarrhea-related deaths among US children <5 years old declined from 1100 to 300/year. This decline was associated with the disappearance of winter peaks for diarrhea-related deaths previously associated with rotavirus infection among children 4-23 months old. From 1979 to 1992, however, hospitalizations for diarrhea averaged 186,000/year and retained their winter peaks, which have been linked to rotavirus infections. Each year an estimated 54,000-55,000 US children are hospitalized for diarrhea, but <40 die with rotavirus. A rotavirus vaccine program will require improved surveillance, including the timely collection of data from sentinel hospitals, in which a diagnosis of rotavirus can be established or ruled out for all children hospitalized for diarrhea.

Child↗