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Biomedical subjects

X M Zhang

Publications and source records attributed to X M Zhang.

At least 19 recordsLinked to original sources
PubMed2006

A novel mitochondrial DNA missense mutation at G3421A in a family with maternally inherited diabetes and deafness.

OBJECTIVE: Mutations in mtDNA are thought to be responsible for the pathogenesis of maternally inherited diabetes. Here, we report a family with maternally inherited diabetes and deafness whose members did not harbour the mtDNA A3243G mutation, the most frequent point mutation in mitochondrial diabetic patients. This study aimed to investigate a possible other mtDNA mutation and its prevalence in type 2 diabetic patients. METHODS: Height, body weight, waistline, and hip circumference were measured and serum biochemical marks determined in all members of the family. In addition, a 75 g oral glucose tolerance test and electric listening test were conducted in these members. Genomic DNA was prepared from peripheral leukocytes. Direct sequencing of PCR products was used to detect the mtDNA mutation in this family. The prevalence of mtDNA G3421A nucleotide substitutions was investigated by restriction fragment length polymorphism analysis in 1350 unrelated type 2 diabetic patients recruited by random cluster sampling from the central city area of Shanghai, China. RESULTS: (1) A new missense homoplasmic mutation of mtDNA G3421A was found in a maternally inherited diabetic family and existed neither in 1350 unrelated type 2 diabetic patients nor in 50 non-diabetic individuals. (2) The mode of mutation and diabetes transmission was typical maternal inheritance in this family. (3) All diabetic family members were found to have an onset at 35-42 years of age, accompanied by deafness of varying degrees. CONCLUSION: mtDNA G3421A (Val39Ile) found in a family with maternally inherited diabetes and deafness is a novel missense mutation. Whether this is a diabetogenic mutation and its effect on mitochondrial function needs to be further studied.

Adolescent↗
PubMed2006

Atrial natriuretic peptide modulates cystic fibrosis transmembrane conductance regulator chloride channel expression in rat proximal colon and human intestinal epithelial cells.

The cystic fibrosis transmembrane conductance regulator (CFTR) is one of the most intensively investigated Cl- channels. Different mutations in the CFTR gene cause the disease cystic fibrosis (CF). CFTR is expressed in the apical membrane of various epithelial cells including the intestine. The major organ affected in CF patients is the lung, but it also causes an important dysfunction of intestinal ion transport. The modulation of CFTR mRNA expression by atrial natriuretic peptide (ANP) was investigated in rat proximal colon and in human intestinal CaCo-2 cells by RNase protection assay and semi-quantitative reverse transcriptase PCR techniques. Groups of rats subjected to volume expansion or intravenous infusion of synthetic ANP showed respective increases of 60 and 50% of CFTR mRNA expression in proximal colon. CFTR mRNA was also increased in cells treated with ANP, reaching a maximum effect at 10(-9) M ANP, probably via cGMP. ANP at 10(-9) M was also able to stimulate both the CFTR promoter region (by luciferase assay) and protein expression in CaCo-2 cells (by Western blot and immunoprecipitation/phosphorylation). These results suggested the involvement of ANP, a hormone involved with extracellular volume, in the expression of CFTR in rat proximal colon and CaCo-2 intestinal cells.

Animals↗
PubMed2006

[Comparison of IgA/VCA, IgA/EA, IgG/EA in immunoenzyme methods and ZEBRA ELISA in early diagnosis of nasopharyngeal carcinoma.].

BACKGROUND: To develop an ELISA method using Herpesvirus hominis type 4 (EBV) IgG/Zebra as capture antigen for large population screening. METHODS: The ELISA method used purified ZEBRA antigen to detect the IgG/ZEBRA antibody from serum in nasopharyngeal carcinoma (NPC) and normal healthy subjects. RESULTS: Of 288 NPC sera, 262 were detected positive, the sensitivity was 91%, while 5 of 96 normal sera were detected positive, the specificity was 94.8% and the results of NPC group and healthy group displayed significant difference (P less than 0.001). IgA/VCA, IgA/EA, IgG/EA in immunoenzyme methods and ZEBRA ELISA were compared during the NPC screening in two cities: Huizhou, Guangdong and Guiping, Guangxi, 5463 and 2017 samples respectively were tested and 5 earlier NPC patients were found. CONCLUSION: The results indicate that this method has high specificity and sensitivity, and can be used for large population screening to assist early phase NPC diagnosis.

Animals↗
PubMed2005

Distribution of sorbed phenanthrene and pyrene in different humic fractions of soils and importance of humin.

Contributions of fulvic-humic acids (FA/HA) and humin (HM) to sorption of phenanthrene (PHE) and pyrene (PYR) in a soil were differentiated using a humic separation procedure after multi-concentration sorption experiments. It was found that the amount of solutes in FA/HA did not change significantly after 48 h, while that in HM increased continuously and slowly up to the end of the experimental period (720 h), indicating that HM was the main region for slow sorption. Based on the fitting results using Freundlich equation, it was found that nonlinearity of both solutes was greater in HM than in FA/HA, consistent with the sorption characteristics of individually extracted HA and HM in a separate experiment. The observed nonlinearity of the solute distribution was confirmed by using three other soil samples with organic carbon contents ranging from 0.7 to 7.9%. Distribution dynamics of PHE and PYR among various fractions were also discussed.

Adsorption↗
PubMed2004

Genetic and genotype x environment interaction effects for the content of seven essential amino acids in indica rice.

It is necessary for rice breeders to understand the genetic basis of nutrient quality traits of rice. Essential amino acids are most important in determining the nutrient quality of rice grain and can affect the health of people who depend on rice as a staple food. In view of the paucity of genetic information available on essential amino acids in indica rice, we estimated the genetic main effects and genotype x environment (G x E) interaction effects on the content of essential amino acids. Nine cytoplasmic male sterile lines as females and five restorer lines as males were introduced in a North Carolina II design across environments. Estimates of the content of the essential amino acids valine, methionine, leucine and phenylalanine showed that they were mainly controlled by genetic main effects, while the contents of threonine, cysteine and isoleucine were mainly affected by G x E effects. In the case of genetic main effects, both cytoplasmic and maternal genetic effects were predominant for all essential amino acids, indicating that selection for improving essential amino acid content based on maternal performance would be more effective than that based on seeds. The total narrow-sense heritabilities were high and ranged from 0.72 to 0.83. Since general heritabilities for these essential amino acids (except for cysteine) were found to be much larger than G x E interaction heritability, the improvement of content of most essential amino acids under selection would be expected under various environments. Rice varieties such as Zhenan 3, Yinchao 1, T49, 26715, 102 and 1391 should be selected as optimal parents for increasing the content of most essential amino acids, while the total genetic effects from Zhexie 2, Xieqingzao, Gangchao 1, V20, Zuo 5 and Zhenshan 97 were mainly negative and these parents could decrease the contents of most essential amino acids.

Amino Acids↗
PubMed2004

Involvement of lymphocytes with a Th1 cytokine profile in bone cell damage associated with MMP-9 production in collagen-induced arthritis.

OBJECTIVE: To investigate whether lymphocytes could directly cause the destruction of bone cells in collageninduced arthritis (CIA) mice and the mechanism of this destruction. METHODS: Arthritis was induced with chick type II collagen in Kunming mice. The activities of TNF-alpha and IFN-gamma were measured by biological methods. The mRNA of TNF-alpha, IFN-gamma, T-bet, a Th1 specific transcription factor and Fas was detected by reverse transcript-polymerase chain reaction (RT-PCR). Matrix metalloproteinase (MMP)-9 was measured by gelatin zymography assay. The cytotoxicity of spleen cells to bone cell populations and the proliferation of spleen cells against chick type II collagen (CII) were examined by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) method. RESULTS: Arthritis was successfully induced by chick CII in Kunming mice, which had remarkable paw swelling and typical features of arthritis. Compared with naive mice, the arthritic mice showed an increased IFN-gamma and TNF-alpha production in serum, and the spleen cells from the arthritic mice displayed a Th1 cytokine profile and directly damaged bone cells in vitro. Interestingly, naive spleen cells treated by phorbol 12-myristate 13-acetate (PMA) also damaged bone cells as did spleen cells from CIA mice. Cyclosporine A blocked the cytotoxicity of spleen cells from CIA mice to bone cells. Only anti-CD4 and complement system together inhibited the effect of spleen cells from CIA mice on bone cells. Only the spleen cells from arthritic mice could proliferate against chick CII. In addition, the culture supernatants from spleen cells of arthritic mice contained a higher activity of MMP-9 and production of NO than those of naive mice. PMA elevated the activity of MMP-9 but not the production of NO in naive spleen cells. Moreover, the activities of TNF-alpha, IFN-gamma and MMP-9 but not the production of NO were higher in joint tissues of arthritic mice than those of naive mice. TNF-alpha and IFN-gamma significantly elevated the activity of MMP-9 in spleen cells from both arthritic and naive mice in vitro. Moreover, only anti-MMP-9 but not anti-MMP-2 antibody inhibited the cytotoxicity of spleen cells from CIA mice to bone cells. CONCLUSIONS: The elevated proinflammatory factors such as TNF-alpha and IFN-gamma may promote the MMP-9 activity in local inflammatory cells that are actually involved in the bone cell damage in CII-induced arthritis.

Animals↗
PubMed2003

High-performance liquid chromatographic determination of polysorbate 80 in pharmaceutical suspensions.

A quick HPLC method is reported for the analysis of polysorbate 80 in pharmaceutical suspensions. A typical pharmaceutical suspension was mixed with dilute potassium hydroxide, and heated at 40 degrees C for 6 h. This procedure resulted in quantitative hydrolysis of polysorbate 80 to release oleic acid. A quick HPLC procedure was used to analyze the hydrolyzed samples without further sample treatment. Polysorbate 80 USP, treated in the same way as the pharmaceutical suspensions, was used as standard. Full validation tests were carried out and the validation studies demonstrated that this method is suitable for accurate and reproducible analysis of polysorbate 80 in pharmaceutical suspensions.

Chromatography, High Pressure Liquid↗
PubMed2003

Noncontact ultrasound stimulated optical vibrometry study of coupled vibration of arterial tubes in fluids.

Coupled vibration of arterial tubes is analyzed with the wave propagation approach and first-order shear deformation theory. Both the interior and exterior fluids are considered as compressible so that acoustic waves can be generated and propagated in the fluids. Results obtained using the theory have been evaluated against those available in the literature and the agreement has been found to be good. The theory can be used for future research on the vibration and acoustics of arterial walls. Vibration experiments were carried out on a silicone rubber tube in a water tank with a novel ultrasound stimulated optical vibrometry system. This system uses the radiation force of ultrasound to vibrate the tube at low frequency and records the resulting response by a laser vibrometer. Both the excitation and measurement are remote and noncontact. The silicone rubber tube was chosen because it has mechanical properties close to those of arteries. The fundamental frequency is well excited by the radiation force and measured with the laser. The measured fundamental frequency is in good agreement with the present theory.

Arteries↗
PubMed2003

Shape identification of underwater objects using backscattered frequency signals.

The inverse problems in the area of the acoustic scattering often concern the determination of the size, shape, and orientation of an object using the scattered field data. This paper presents a method to retrieve the shape information of an underwater object using illuminated lengths, which can be obtained from the ramp response signatures of the object. An ellipsoidal object submerged in water is considered. Both the low and high backscattered frequency data have been employed to calculate the illuminated lengths. The calculated results show that the illuminated lengths will be more accurate, if only the high-frequency-range data are employed. For ellipsoidal objects, any three illuminated lengths that are not of a same plane can in theory fully determine the shape of the ellipsoid. As the calculated illuminated lengths contain numerical errors, the calculated results of the three semiaxes of the ellipsoid will deteriorate and become unreliable, especially when the three incident directions of the illuminated lengths become close. The reason is that the condition number of the coefficient matrix becomes big in such situations, which leads to an increase of the relative error upper limit in the calculated results. To avoid such errors in close incident wave cases, it is found that the use of more than three incident waves works very well in the shape identification of an underwater object.

Journal Article↗
PubMed2002

Liver-infiltrating T lymphocytes cause hepatocyte damage by releasing humoral factors via LFA-1/ICAM-1 interaction in immunological liver injury.

OBJECTIVE AND DESIGN: To explore the mechanisms by which liver-infiltrating T lymphocytes cause hepatocyte damage in the liver injury induced by delayed-type hypersensitivity to picryl chloride. MATERIALS AND METHODS: Nonparenchymal cells (NPC) were isolated 12 h after liver injury elicitation and fractionated into Kupffer cell-enriched (Fr. A) and lymphocyte-enriched populations (Fr. B). They were used as the effectors for coculture with hepatocytes. RESULTS: The cells in total NPC and Fr. B harvested at 12 h of liver injury were increased two- and six-fold respectively compared with those at 0 h. Fr. B, mainly including CD4+ and CD8+ T cells, exhibited a significantly stronger hepatotoxicity than total NPC did, while Fr.A did not. NPC at 12 h showed remarkably increased matrix metalloproteinase-2 and -9 activities indicative of infiltration potential through extracellular matrix. When NPC and hepatocytes were cultured in separated compartments in Transwell chamber, no hepatotoxicity was observed. However, 30 min-pre-contact with hepatocytes as stimulator significantly triggered NPC hepatotoxicity. The acquisition of such hepatotoxic potential was significantly abolished by anti-LFA-1 pretreatment for NPC or anti-ICAM-1 treatment for hepatocytes before contact. Both aprotonin and superoxide dismutase dose-dependently inhibited the hepatotoxicity. CONCLUSIONS: Liver-infiltrating T lymphocytes may be triggered by hepatocytes via LFA-1/ICAM-1 interaction to release toxic substances, such as proteases and oxygen radicals, which consequently lead to the hepatocyte damage.

Alanine Transaminase↗
PubMed2001

In vivo transtracheal adenovirus-mediated transfer of human interleukin-10 gene to donor lungs ameliorates ischemia-reperfusion injury and improves early posttransplant graft function in the rat.

We examined the effect of adenovirus-mediated transtracheal transfer of the human interleukin 10 (hIL-10) gene on lung ischemia-reperfusion (IR) injury, which is the insult due to hypothermic preservation plus graft reperfusion, and posttransplant lung function in Lewis rat lungs. Thirty rats were divided into 6 groups (n = 5). Groups 1 and 4 received 5 x 10(9) PFU of Ad5E1RSVhIL-10, groups 2 and 5 received 5 x 10(9) PFU of Ad5BGL2 ("empty" vector), and groups 3 and 6 received 3% sucrose (diluent). After 24 hr of in vivo transfection, lungs were stored at 4 degrees C (cold ischemic time, CIT) for 6 hr (groups 1-3) or 24 hr (groups 4-6) before transplantation. After 2 hr of reperfusion, lung function was assessed by oxygenation (FIO2, 1.0), airway pressure (AwP), and wet-to-dry (W/D) weight ratios. Rat tumor necrosis factor alpha (rTNF-alpha), interferon gamma (IFN-gamma), IL-10, and hIL-10 were measured in graft tissue and recipient plasma by ELISA and detected by immunohistochemistry (IHC). Partial pressure of oxygen (PaO2) levels in the hIL-10 group (6 hr of CIT) were higher than in empty vector and diluent groups (PaO2, 530 +/- 23 vs. 387 +/- 31 and 439 +/- 27 mmHg, respectively, p < 0.05). IL-10 rats after 24 hr of CIT showed higher PaO2 levels (260 +/- 29 mmHg) than empty vector (96 +/- 24 mmHg) or diluent (133 +/- 10 mmHg) lungs (p < 0.05). AwP and W/D ratios were reduced in hIL10 lungs (p < 0.05) compared with the other groups. rTNF-alpha and INF-gamma were reduced in tissue and plasma in groups 1 and 4 (p < 0.05). rIL-10 was reduced in the tissue of hIL-10 lungs (p < 0.05). IHC showed equal distribution of cytokines in tissue and abundant transgene expression in large and small airway epithelium in hIL-10 lungs.

Adenoviridae↗
PubMed2001

Heart regeneration in adult MRL mice.

The reaction of cardiac tissue to acute injury involves interacting cascades of cellular and molecular responses that encompass inflammation, hormonal signaling, extracellular matrix remodeling, and compensatory adaptation of myocytes. Myocardial regeneration is observed in amphibians, whereas scar formation characterizes cardiac ventricular wound healing in a variety of mammalian injury models. We have previously shown that the MRL mouse strain has an extraordinary capacity to heal surgical wounds, a complex trait that maps to at least seven genetic loci. Here, we extend these studies to cardiac wounds and demonstrate that a severe transmural, cryogenically induced infarction of the right ventricle heals extensively within 60 days, with the restoration of normal myocardium and function. Scarring is markedly reduced in MRL mice compared with C57BL/6 mice, consistent with both the reduced hydroxyproline levels seen after injury and an elevated cardiomyocyte mitotic index of 10-20% for the MRL compared with 1-3% for the C57BL/6. The myocardial response to injury observed in these mice resembles the regenerative process seen in amphibians.

Animals↗
PubMed2001

Smoothened mutants reveal redundant roles for Shh and Ihh signaling including regulation of L/R symmetry by the mouse node.

Genetic analyses in Drosophila have demonstrated that the multipass membrane protein Smoothened (Smo) is essential for all Hedgehog signaling. We show that Smo acts epistatic to Ptc1 to mediate Shh and Ihh signaling in the early mouse embryo. Smo and Shh/Ihh compound mutants have identical phenotypes: embryos fail to turn, arresting at somite stages with a small, linear heart tube, an open gut and cyclopia. The absence of visible left/right (L/R) asymmetry led us to examine the pathways controlling L/R situs. We present evidence consistent with a model in which Hedgehog signaling within the node is required for activation of Gdf1, and induction of left-side determinants. Further, we demonstrate an absolute requirement for Hedgehog signaling in sclerotomal development and a role in cardiac morphogenesis.

Animals↗
PubMed2001

[Effect of peritonitis pathomorphology on rabbit model in peritoneal dialysis].

The study about peritonitis rabbit model is rarely, although peritonitis have been considered mainly complication in peritoneal dialysis. Twelve New Zealand rabbit were divided into peritonitis group and control group. The peritonitis group rabbit were injected with the dialysate containing alive staphylococcus aureus and the control ones with 0.9% saline into the peritoneum. The pathomorphology changes of the peritonitis were observed. The results showed (1) There was proliferation and swollen of mesothelial cells, vessel dilation and infiltration of inflammation cells in the peritoneum in the peritonitis group; and no such changes in the control group. (2) The D/D0 glucose concentration in the dialysate of peritonitis group was lower than that of the control ones at any point except the 0 min (P < 0.01). (3) The ratio of Cr concentration in the dialysate to Cr concentration in the plasma in the peritnitis group was significantly higher than that of the control group (P < 0.05). (4) The WBC count in the dialysate of peritonitis group was obviously higher than that of the control group all points except 0. These results implied that after injection of alive staphylococcus aureus to the peritoneal cavity of New Zealand rabbit for 48 hours, the pathomorphology change was similar with the characteristics of peritonitis complicated with peritoneal dialysis in patient.

Animals↗
PubMed2001

Smoothened mutants reveal redundant roles for Shh and Ihh signaling including regulation of L/R asymmetry by the mouse node.

Genetic analyses in Drosophila have demonstrated that the multipass membrane protein Smoothened (Smo) is essential for all Hedgehog signaling. We show that Smo acts epistatic to Ptc1 to mediate Shh and Ihh signaling in the early mouse embryo. Smo and Shh/Ihh compound mutants have identical phenotypes: embryos fail to turn, arresting at somite stages with a small, linear heart tube, an open gut and cyclopia. The absence of visible left/right (L/R) asymmetry led us to examine the pathways controlling L/R situs. We present evidence consistent with a model in which Hedgehog signaling within the node is required for activation of Gdf1, and induction of left-side determinants. Further, we demonstrate an absolute requirement for Hedgehog signaling in sclerotomal development and a role in cardiac morphogenesis.[Dedicated to Rosa Beddington, a pioneer in mammalian embryology].

Animals↗
PubMed2001

Temporal and spatial effects of Sonic hedgehog signaling in chick eye morphogenesis.

Proper dorsal--ventral pattern formation of the optic cup is essential for vertebrate eye morphogenesis and retinotectal topographic mapping. Previous studies have suggested that midline tissue-derived Sonic hedgehog (Shh) molecules play critical roles in establishing the bilateral eye fields and in determining the proximal--distal axis of the eye primordium. Here, we have examined the temporal requirements for Shh during the optic vesicle to optic cup transition and after early optic cup formation in chick embryos. Both misexpressing Shh by virus and blocking Shh activity by antibodies resulted in disruption of ventral ocular tissues. Decreasing endogenous Shh signals unexpectedly revealed a sharp morphological boundary subdividing dorsal and ventral portions of the optic cup. In addition, Shh signals differentially influenced expression patterns of genes involved in ocular tissue specification (Pax6, Pax2, and Otx2) and dorsal--ventral patterning (cVax) within the ventral but not dorsal optic cup. Ectopic Shh suppressed expression of Bone Morphogenetic Protein 4 (BMP4) in the dorsal retina, whereas reducing endogenous Sonic hedgehog activity resulted in a ventral expansion of BMP4 territory. These results demonstrate that temporal requirements for Shh signals persist after the formation of the optic cup and suggest that the early vertebrate optic primordium may be subdivided into dorsal and ventral compartments. We propose a model in which ventrally derived Shh signals and dorsally restricted BMP4 signals act antagonistically to regulate the growth and specification of the optic primordium.

Animals↗