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Biomedical subjects

Y X Zhao

Publications and source records attributed to Y X Zhao.

35 records · Page 2Linked to original sources
PubMed1995

Mice with the xid B cell defect are less susceptible to developing Staphylococcus aureus-induced arthritis.

To investigate the role of B cells in the development of experimental Staphylococcus aureus-induced arthritis, we used X-linked immunodeficiency (xid) mice that carry a Bruton's tyrosine kinase mutation affecting the function of B cells. NFR/N.xid and congenic NFR/N mice were inoculated i.v. with a toxic syndrome toxin-1 producing S. aureus LS-1 strain. B cell-deficient NFR/N.xid mice developed less frequent (p < 0.01) and less severe (p < 0.01) arthritis than NFR/N mice did. These clinical findings were corroborated by histopathologic evaluation, indicating that NFR/N.xid mice had significantly lower (p < 0.01) erosivity of the disease. Interestingly, infected NFR/N.xid mice showed decreased bacterial burden in blood, joints, and other organs compared with the control mice. Serologic studies displayed poor B cell responses to staphylococcal cell walls, toxic shock syndrome toxin-1, and ssDNA, accompanied by a low level of Igs in infected NFR/N.xid mice. More importantly, xid defect affected cytokine profile. The in vitro experiments showed that the lymphocytes from NFR/N.xid mice had low IL-6, but high IFN-gamma production upon stimulation with staphylococcal cell walls compared with NFR/N mice. Furthermore, the in situ hybridization technique revealed the relative increase of IFN-gamma, but marked decrease of IL-1 beta mRNA expression in spleens of infected NFR/N.xid mice. No significant difference in IL-4, IL-10, and TNF-alpha mRNA expression was found between both strains. Our findings demonstrate that B cells may, directly or indirectly, contribute to the pathogenesis of septic arthritis. The results indicate that increased IFN-gamma production along with low IL-6 and IL-1 beta synthesis found in xid mice may provide a more favorable outcome of S. aureus arthritis.

Animals↗
PubMed1995

Patterns of interferon-gamma mRNA expression in toxic shock syndrome toxin-1 expanded V beta 11+ T lymphocytes.

We have recently demonstrated that toxic shock syndrome toxin-1 (TSST-1), a staphylococcal exotoxin with superantigenic properties, is involved in the pathogenesis of septic arthritis. The aim of the current study was to characterize in detail the in vitro properties of TSST-1 with regard to T cell activation patterns. We demonstrate that TSST-1 preferentially expands murine V beta 11+ T lymphocytes and this expansion occurs equally well within CD4 and CD8 compartments. To analyze the functional properties of V beta 11+ T cells expanded in response to TSST-1, we have utilized a combined in situ hybridization and immunocytochemistry method. With this technique we show that TSST-1-stimulated V beta 11+ T cells are an important source of IFN gamma mRNA synthesis, suggesting that this cytokine may participate in superantigen-mediated septic arthritis.

Animals↗
PubMed1995

Overexpression of the T-cell receptor V beta 3 in transgenic mice increases mortality during infection by enterotoxin A-producing Staphylococcus aureus.

We have previously demonstrated that staphylococcal enterotoxins contribute to arthritis and mortality during staphylococcal infection. To further explore the mechanism by which bacterial superantigens contribute to the pathogenesis of Staphylococcus aureus septicemia, T-cell receptor V beta 3 transgenic (TGV beta 3) mice and nontransgenic (non-TG) littermates were inoculated intravenously with S. aureus AB-1, which produces large amounts of staphylococcal enterotoxin A, which specifically reacts with T-cell receptor V beta 3. Within 9 days after inoculation, 85% of the TGV beta mice died, compared with 31% of their non-TG littermates (P < 0.01). The high mortality of TGV beta 3 mice was accompanied by elevated bacterial burdens in the blood, spleen, and kidneys. The in vivo kinetics of cytokine mRNA expression was studied by an in situ hybridization technique. Staphylococcal infection gave rise to increased expression of interleukin 1 beta (IL-1 beta) mRNA and sparsely expressed tumor necrosis factor alpha (TNF-alpha), IL-4, and IL-10 mRNAs in both groups. Gamma interferon mRNA expression increased on day 3 and was maintained at a detectable level in the late phase of infection in TGV beta 3 mice, in contrast to non-TG mice. Impressively, significantly higher expression of TNF-beta mRNA in TGV beta 3 mice was noted throughout the course of infection than in non-TG littermates. These findings suggest that overproduction of TNF-beta and gamma interferon, the Th1 cytokines, may play a crucial role in the pathogenesis of septicemia caused by enterotoxin-secreting staphylococci.

Animals↗
PubMed1994

[Determination of hexamethylene bisacetamide in plasma by high performance liquid chromatography].

A high performance liquid chromatographic assay was developed for determination of the plasma concentration of hexamethylene bisacetamide (HMBA) in rabbit. Plasma samples were vortex-mixed with 0.3 ml of methanol and centrifuged at 10000 r/min for 5 min. A 20 microliters aliquot of the supernatant was injected into the HPLC system. Analysis was performed on a Du Pont Zorbax C18 column (250 mm x 4.6 mm, 10 microns) with a precolumn (50 mm x 4.6 mm, 10 microns, YWG-C18). The eluent was methanol--water (30:70), with flow rate of 1.0 ml.min-1 and UV detection at 210 nm. The limit of detection was 1.0 microgram.ml-1 in plasma and the calibration curve was linear over the range 5-1000 micrograms.ml-1 (r = 0.9988). The HPLC assay was applied for studying the pharmacokinetics of HMBA in rabbit.

Acetamides↗
PubMed1993

Reliability and accuracy of measurement of transductal gradient by Doppler ultrasound.

Simultaneous continuous wave Doppler echocardiography, aortic and pulmonary artery pressure measurements were performed during cardiac catheterization in 46 patients with patent ductus arteriosus. Doppler-derived systolic, mean and diastolic transductal gradients correlated well with those measured by catheterization, respectively (r = 0.972, SEE = 6.8 mmHg; r = 0.965, SEE = 5.4 mmHg; r = 0.939, SEE = 6.2 mmHg), and there were clinically acceptable agreements between the two technical measurements. It is concluded that Doppler echocardiography is a reliable and accurate technique for noninvasive estimation of transductal gradients.

Adolescent↗
PubMed1993

Quantification of left-side intracardiac pressures and gradients using mitral and aortic regurgitant velocities by simultaneous left and right catheterization and continuous-wave Doppler echocardiography.

Noninvasive determination of left-side intracardiac pressures is of clinical importance in many cardiac diseases. To test the reliability and accuracy of left-side intracardiac pressure measurements by continuous-wave Doppler echocardiography, using left-side valvular regurgitations, 47 patients with mitral regurgitation, with or without associated aortic regurgitation, underwent simultaneous Doppler and left and right catheterization. Doppler-derived left atrial and ventricular end-diastolic pressures were respectively estimated by subtracting mitral regurgitant gradient from systolic blood pressure and by diastolic blood pressure minus aortic regurgitant gradient. There were high correlations of mitral (r = 0.961) and aortic regurgitant gradients (r = 0.896) and of left atrial (r = 0.945) and ventricular end-diastolic pressures (r = 0.854) between noninvasive and invasive measurements. Also, agreement analyses showed that there was close agreement between the two technical measurements for each parameter. The present study concluded that continuous-wave Doppler echocardiography provides a reliable and accurate method for the noninvasive evaluation of left-side intracardiac pressures and gradients in patients with mitral and aortic regurgitations.

Adolescent↗
PubMed1992

Comparison of the anatomic distribution of stomach cancer and precancerous gastric lesions.

The anatomic distribution of precancerous gastric lesions among 3,400 residents in Linqu, Shandong Province of China, was compared with the anatomic distribution of stomach cancer (SC) among 959 patients in Tokyo, Japan. The incidence of SC is high in both areas, and locations within the stomach of the precancerous and malignant lesions were classified using similar criteria. Chronic atrophic gastritis (CAG) affected 98% of the population in Linqu, with intestinal metaplasia (IM) the most severe diagnosis in 33% and dysplasia (DYS) in 20%. Neither the SC nor precancerous lesions were uniformly distributed in the stomach. Among the DYS 3% were along the greater curvature of the body, 15% along the lesser curvature of the body, 25% in the angulus, 22% along the lesser curvature of the antrum, and 34% elsewhere in the antrum. Among the SC the corresponding percentages were 2, 16, 28, 25 and 29. The similarity to the SC distribution increased gradually from CAG to IM to DYS, providing further evidence for the multistage progression of precancerous gastric lesions.

Adult↗
PubMed1989

[Projection of afferent impulses from the brachial plexus and sciatic nerve to the corpus striatum in pigeons].

The corpus striatum were systematically explored by recording averaged potentials elicited by stimulation of the brachial plexus and sciatic nerve in 53 pigeons. It was found that the projection areas of brachial afferents were located within the neostriatum, the hyperstriatum and the ectostriatum. The sciatic projection areas overlap with the brachial projection areas in the neostriatum and a part of the hyperstriatum. Moreover, the brachial and sciatic projection are as in the striatum receive the inputs from both sides of the body. We suggest that the somatic projection areas of fore- and hindlimb are distributed diffusely in the striatum of the pigeon. That the projection area of forelimb is relatively larger is probably related with functional differentiation of the forelimb. Furthermore, the convergence of afferent impulses originating in the different regions of the body within the same brain area may be important for the integration of limb activities in pigeon.

Afferent Pathways↗
PubMed1987

[Pattern recognition on the trace element spectrum in gastric cancer and peptic ulcer].

The trace element spectrum of gastric tissue and whole blood specimens from gastric cancer and peptic ulcer patients was recognized with pattern recognition technique in order to obtain the chemical information of gastric cancer. Thirty specimens were obtained from cancer patients in each of the 58 gastric tissues and 54 whole blood specimens. Five pathological types were divided into two groups: peptic ulcer and dysplasia as the ulcer group; well-differentiated, undifferentiated and mucinous carcinoma as the cancer group. The accuracy of recognizing the several spectra was 90%: nine trace element spectra (Cu, Zn, Ni, Co, Cr, Cd, Mn, Fe and Mg) for the tissue specimens from the cancer and ulcer groups; six (Cu, Zn, Mn, Co, Cr and Cd) for dysplasia and well-differentiated adenocarcinoma tissues; five (Cu, Ni, Cr, Cd and Fe) for the whole blood specimens from these two groups and six (Cu, Zn, Cr, Cd, Fe and Ni) for the whole blood specimens from dysplasia and peptic ulcer (including 10 normal individuals). The data were treated by non-linear mapping method and calculated by TRS-80 III type microcomputer.

Adenocarcinoma↗
PubMed1983

Absolute configuration of (-)anisodine (a new ganglio blocking agent) and (-)anisodinic acid.

A new tropane alkaloid, (-)anisodine (I), was isolated from the plant of Anisodus tanguticus. It is a novel ganglio blocking agent. The absolute configuration of (-)anisodinic acid (VII), which is the side chain of (-)anisodine, was determined by chemical correlation with (R) (-)-2-phenyl-1, 2-propanediol (IV) and (R) (-)-2-hydroxy-2-phenylpropionic acid (VI). Thereby (-)anisodine with the absolute configuration shown as (I) is 6 beta, 7 beta-epoxy-1 alpha H, 5 alpha H-tropan-3 alpha-ol (S) 2'-phenyl-2', 3'-dihydroxypropionate. Two new tropane alkaloids; 6 beta, 7 beta-epoxy-1 alpha H, 5 alpha H-tropan-3 alpha-ol 2',3'-epoxypropionate (III) and 2'-phenyl-2'-hydroxypropionate (V) were prepared and its physical constant is reported in this paper.

Ganglionic Blockers↗