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Biomedical subjects

J Qian

Publications and source records attributed to J Qian.

223 records · Page 13Linked to original sources
PubMed1983

Effect of adrenalectomy and demedullation of the adrenals on vasopressor responses to stimulation of postjunctional alpha 2-adrenoceptors.

After adrenalectomy performed 18-12 h previously, the vasopressor responses induced by stimulation of postjunctional alpha 2-adrenoceptors (agonist: B-HT 920) were attenuated in pithed normotensive rats in contrast to pressor responses mediated by postjunctional alpha 1-adrenoceptors (agonist: cirazoline). Aldosterone and desoxycorticosterone both enhanced the vasopressor responses to the alpha 2-adrenoceptor agonist B-HT 920 in adrenalectomized rats, but did not fully restore the effects. Demedullation of the adrenals also attenuated the vasoconstrictor processes evoked by stimulation of postjunctional alpha 2-adrenoceptors 18-22 h later. This effect was reversed after an infusion with adrenaline. The combination of aldosterone and adrenaline produced full recovery of the increase in diastolic pressure elicited via alpha 2-adrenoceptors in adrenalectomized (18-22 h) animals. The results suggest that circulating adrenaline and aldosterone (or corticosterone) are required for optimal functioning of vascular postjunctional alpha 2-adrenoceptors.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Immobilization of glucose oxidase with the blend of regenerated silk fibroin and poly(vinyl alcohol) and its application to a 1,1'-dimethylferrocene-mediating glucose sensor.

The structure and properties of the blend of regenerated silk fibroin (RSF) and poly(vinyl alcohol) (PVA) were investigated. The two polymers in the blend are in the state of phase segregation. Infrared (IR) spectra indicate that the RSF in the blend maintains its intrinsic properties, thus, ethanol treatment can transfer silk I structure of RSF to silk II structure. The water absorption property and mechanical property of the blend are improved in comparison with those of RSF. The blend maintains the major merit of RSF, that is, it can immobilize glucose oxidase on the basis of the conformational transition from silk I structure to silk II structure. The properties of the immobilized enzyme are examined. Moreover, the second generation of glucose sensor based on the immobilized enzyme is fabricated and it has a variety of advantages including easy maintenance of enzyme, simplicity of construction, fast response time and high stability.

Biosensing Techniques↗
PubMedDate not supplied

Dysregulation of lymphokine production in the neonate and its impact on neonatal cell mediated immunity.

Haematopoiesis and immune functions in cord blood (CB) are developmentally immature when compared with adult peripheral blood (APB). The defects in CB immune function and cytokine production may both contribute to the immaturity of CB immunity. We have studied the mechanisms associated with the dysregulation of myeloid lineage cytokines, GM-CSF and M-CSF, and lymphokines, IL-12, and IL-15 in activated CB when compared with APB MNC. Furthermore, we have studied the effects of IL-12 and IL-15 on induction of IFN-gamma and TNF-alpha production, NK, and LAK activities in CB and APB. GM-CSF, M-CSF, IL-12 and IL-15 protein and mRNA are decreased in activated CB MNC. These discrepancies are secondary, at least in part, to the altered post-transcriptional regulation. The impaired ability of CB to produce IL-12 and IL-15 in response to stimulation may contribute to the decrease in IFN-gamma, TNF-alpha production, NK and LAK activities. Furthermore, combination of low dose IL-12 and IL-15 may augment cytotoxic activities and minimize toxicity. These findings suggest that reduced cytokine expression from activated CB may contribute to the impaired CB cellular immunity and exogenous lymphokines may compensate for the immaturity in CB.

Adult↗
PubMedDate not supplied

Heat shock protein-induced T-lymphocyte propagation from endomyocardial biopsies in heart transplantation.

BACKGROUND: Recent studies have shown that heat shock proteins can be recognized by T cells during various immunologically mediated inflammatory processes. Injurious stimuli to cells induce an increased production of heat shock proteins which could lead to their cell surface expression and subsequent recognition by the immune system. We have postulated that allograft infiltrating cells may recognize heat shock proteins, especially during rejection. METHODS: This hypothesis was tested by incubating heart transplant biopsy specimens from 89 heart transplant recipients with soluble Mycobacterium tuberculosis extracts, a source of heat shock proteins or recombinant mycobacterial heat shock protein 65. T cell phenotypes were determined by flow cytometry. RESULTS: Mycobacterium tuberculosis extract can induce lymphocyte propagation from heart transplant biopsy specimens especially during rejection. A highly significant correlation was seen between Mycobacterium tuberculosis extract and interleukin-2-induced lymphocyte growth and an accelerated growth was seen for cultures incubated with Mycobacterium tuberculosis extract + interleukin-2. A second series of experiments has also shown the propagation of lymphocytes induced by recombinant mycobacterial heat shock protein-65. T-cell phenotype analysis of biopsy propagated lymphocytes has shown higher frequencies of CD8 cells in Mycobacterium tuberculosis extract and heat shock protein-65 propagated lymphocytes from early posttransplantation biopsy specimens, whereas, later on, most cultures showed a predominance of CD4 cells. T-cell receptor gamma delta cells were more frequently found in biopsy-derived lymphocyte cultures from long-term survivors, especially after propagation with Mycobacterium tuberculosis extract and heat shock protein-65. These gamma delta cells expressed primarily the delta 1 rather than the gamma 9 phenotype. CONCLUSIONS: These observations provide first evidence for the presence of heat shock protein-reactive lymphocytes in cellular infiltrates of transplants undergoing rejection.

Adult↗
PubMedDate not supplied

The definition and preoperative prediction of clinically insignificant prostate cancer.

OBJECTIVES: To define clinically insignificant prostate cancer according to cancer volume, grade, cancer doubling time, and life expectancy; and to determine how many insignificant cancers are removed by radical prostatectomy. DESIGN AND PATIENTS: Clinically insignificant cancer was defined as a tumor that would give rise to no more than 20 cm3 of cancer within the prostate by the time of expected patient death (1990 life tables) and whose Gleason score was less than 4 in 40- to 49-year-olds, 5 in 50- to 59-year-olds, 6 in 60- to 69-year-olds, and 7 in 70- to 79-year-olds. Four definitions were formulated based on assumed cancer volume doubling times of 2, 3, 4, and 6 years. Using these four definitions, we reviewed 337 totally embedded prostates removed at Mayo Clinic between 1991 and 1993 for clinical stage T1c through T3 cancer to determine how many contained clinically insignificant cancer. MAIN OUTCOME MEASURES: Clinically significant vs clinically insignificant prostate cancer. RESULTS: For cancer volume doubling time of 2, 3, 4, and 6 years, clinically insignificant cancer was identified in one (0.3%), 13 (3.9%), 25 (7.4%), and 49 (14.5%) of 337 prostatectomy specimens, respectively. CONCLUSIONS: Clinically insignificant prostate cancer can be defined by cancer volume, grade, cancer volume doubling time, and life expectancy of the patient. According to our definitions, most men treated with radical prostatectomy have clinically significant cancer.

Adult↗