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Biomedical subjects

Hong Zheng

Publications and source records attributed to Hong Zheng.

At least 91 records · Page 5Linked to original sources
PubMed2003

UNC-52/perlecan affects gonadal leader cell migrations in C. elegans hermaphrodites through alterations in growth factor signaling.

The unc-52 gene of Claenorhabditis elegans encodes a homologue of the basement membrane heparan sulfate proteoglycan perlecan. Viable alleles reduce the abundance of UNC-52 in late larval stages and increase the frequency of distal tip cell (DTC) migration defects caused by mutations disrupting the UNC-6/netrin guidance system. These unc-52 alleles do not cause circumferential DTC migration defects in an otherwise wild-type genetic background. The effects of unc-52 mutations on DTC migrations are distinct from effects on myofilament organization and can be partially suppressed by mutations in several genes encoding growth factor-like molecules, including EGL-17/FGF, UNC-129/TGF-beta, DBL-1/TGF-beta, and EGL-20/WNT. We propose that UNC-52 serves dual roles in C. elegans larval development in the maintenance of muscle structure and the regulation of growth factor-like signaling pathways.

Animals↗
PubMed2003

Cell surface expression of heat shock protein gp96 enhances cross-presentation of cellular antigens and the generation of tumor-specific T cell memory.

Gp96 is an endoplasmic reticular heat shock protein (HSP). We have shown previously that surface expression of gp96 (96tm) on tumor cells led to the activation of dendritic cells and increased anti-tumor immunity. In this report, we have found that protective immunity elicited by 96tm+ tumor cells was tumor-specific and long-lasting. Both CD4+ and CD8+ T cell memory were elicited. By immunizing with tumor cells loaded with the chicken ovalbumin (ova) model antigen, we demonstrated that the priming of adoptively transferred ova-specific CD8+ T cells could occur across MHC haplotypes. The efficiency of this cross priming can be significantly increased when mice were immunized with whole cells that express both ova and cell surface gp96 (ova+96tm+). Mere mixture of soluble ova with 96tm-expressing tumor cells (ova-96tm+) was insufficient, arguing for further processing of ova and perhaps the participation of 96tm-ova complexes in this process. We further compared the relative efficiency of two whole cell vaccines based on the manipulation of gp96 expression in one system: 96tm+ whole cells and cells that secrete the gp96-Ig fusion protein. We found that both vaccines are effective in a prophylactic model against tumors. Our study has reinforced the notion that the manipulation of the site of expression of HSPs may be an effective approach for cancer immunotherapy.

Animals↗
PubMed2003

Heat shock factor 1-independent activation of dendritic cells by heat shock: implication for the uncoupling of heat-mediated immunoregulation from the heat shock response.

The induction of heat shock proteins by heat shock is classically defined as the heat shock response, which is involved in cytoprotection, inflammation and immune responses. Whereas the cytoprotective properties of heat shock have been well characterized, the immunomodulating roles of the heat shock response on the immune system are just emerging. In particular, it is not known whether immunomodulating functions of heat are mediated by the heat shock response. We addressed this question genetically, using a murine model that is unable to mount the heat shock response because of deletion of a major transcriptional factor, heat shock factor 1 (Hsf1). We focused on the roles of heat shock on modulating the functions of dendritic cells (DC) because of their important roles in both innate and adaptive immunity. We found that heat shock matures CD11c(+) DC both in vitro and in vivo, phenotypically and functionally, in the absence of any exogenous inflammatory stimuli. Furthermore, heat-shock-mediated DC maturation is independent of Hsf1, as Hsf1(-/-) DC can be matured by heat shock equally well as wild-type DC. Our novel findings demonstrate that heat shock, one of the most primitive biological responses, can modulate the immune response without the requirement for the transcriptional induction/repression of target genes mediated by Hsf1.

Animals↗
PubMed2003

Spermatogenesis after scrotal reconstruction.

Objective. To explore the effect of scrotal reconstruction following avulsion on spermatogenesis. Methods. Three patients were followed-up after having their scrotums reconstructed. Two scrotums were reconstructed by skin flap. Another patient's testicles were buried in thigh pockets. The follow-up continued from 3 months to 4 years after operation, and we examined the sperm quality, sexual function, sexual hormone, and testis biopsy. Results. The follow-up data showed that the spermatogenesis was not altered in the early stage (up to three months), but was substantially abnormal in the late stage (after two years). Conclusions. Using the thick skin flaps, or burying the testicle for scrotum reconstruction are not recommended for patients who wish to remain fertile.

Adult↗
PubMed2003

Sensations from initial exposure to nicotine predicting adolescent smoking in China: a potential measure of vulnerability to nicotine.

Sensations derived from initial exposure to nicotine are a potential indicator of an individual's vulnerability to nicotine. This study assessed whether sensations experienced during the first lifetime exposure to nicotine could predict current and established cigarette smoking. Data from 210 respondents who reported having ever tried cigarette smoking in Wuhan, China, were obtained for this study from 610 students in 10th grade at two schools. Subjects were participants in a multipurpose pilot survey for an adolescent smoking prevention trial. The survey was administered in a classroom setting using a paper-and-pencil questionnaire. Sensations reported were cigarette smell (59.2%), coughing (54.1%), dizziness (52.1%), nausea (42.5%), relaxation (19.1%), and pleasurable buzz/rush (9.0%). After controlling for confounders, multiple logistic regression analyses identified three sensations significantly associated with smoking: (a) Cigarette smell (OR for days smoked in the past 30 days=2.93, p<.05, OR for number of cigarettes smoked per day=2.69, p<.05, and OR for 100-cigarette smoking=5.40, p<.01), (b) pleasurable buzz/rush (OR for 100-cigarette smoking=11.09, p<.05), and (c) relaxation (OR for past 30-day smoking measures ranged from 3.69 to 4.48, p<.01, and OR for 100-cigarette smoking=4.12, p<.05). A dose-response relationship was observed between the sensations and cigarette smoking. Self-reported sensations from initial exposure to nicotine may be a useful indicator of an individual's vulnerability to nicotine. This information can be used for adolescent smoking prevention and cessation interventions.

Adolescent↗
PubMed2003

[Study on the level of specific IgG, IgG1 and IgE during anaphylactic shock in sheep induced by Echinococcus granulosus].

OBJECTIVE: To investigate the change of specific antibodies IgG, IgG1 subclass and IgE in sheep infected with Echinococcus granulosus (E. g) during anaphylactic shock, and to observe antigen B reactivity against IgG antibody in E. g-infected sheep. METHODS: Antigen B and crude antigen were prepared with E. g cyst fluid (EgCF) from infected sheep. The enzyme-linked immunosorbent assay(ELISA) was used for detecting the level of specific IgG, IgG1 and IgE during anaphylactic shock in sheep induced by E. g. RESULTS: The level of specific IgG, IgG1 and IgE was significantly higher in the infected sheep after 6 months than that of the uninfected control group (P < 0.01). The IgE level decreased rapidly after anaphylactic shock induced, especially when the sheep was dying. Following an antigen challenge the sheep showed a general decrease in total IgG and IgG1 subclass. The total IgG showed a slight change at the beginning, followed by a decrease 1 h after challenge. The decrease of IgG1 subclass was more significant than the total IgG in 40 min after challenge injection. The positive rate was 91% for antigen B and 32% for crude antigen of EgCF against IgG antibody in E. g-infected sheep. CONCLUSION: The specific IgE plays a major role in the anaphylactic shock, while IgG and IgG1 antibodies are also important. Antigen B derived from sheep E. g cyst fluid appears to be useful in serodiagnosis of and monitoring on the infection status in sheep.

Anaphylaxis↗
PubMed2003

[A study of the reconstructed vocal cords in dogs by electron microscopy].

OBJECTIVE: To make an assessment of the reconstruction of dog's vocal cord after cordectomy in experimental study. METHODS: The unilateral vocal cord, laryngeal ventricle, partial anteroinferior portion of ventricular band and the homolateral inner perichondrium of the thyroid cartilage were excised. The upper and lower neighboring soft tissues of the laryngeal traumatic area were relaxed and the superior part was sutured to the inferior part to clear up the laryngeal traumatic area. RESULTS: Under electron microscope, the reconstructed vocal cord was made of numerous collagenous fibers, a few of elastic fibers and atrophic rhabdium. CONCLUSION: The use of the remained ventricular band for repairing the laryngeal wound surface is a useful procedure to get better phonetic function after laryngeal tumor excision providing that the lesion is confined to the vocal cord and laryngeal ventricle.

Animals↗
PubMed2003

The effect of electrolyte imbalance on weaning from cardiopulmonary bypass: an experimental study.

An imbalance in electrolyte concentration during separation from cardiopulmonary bypass (CPB) may lead to a disruption in excitation-contraction coupling resulting in a failure to wean. The etiology of myocardial dysfunction is multifactorial, and includes alterations in acid-base balance, glucose metabolism, and cellular function. The purpose of this study was to assess the effect of hyperkalemia on myocardial function during separation from CPB. A porcine model (n = 5) of hypothermic (32 degrees C) CPB was used where hyperkalemia [K+ (6.5 +/- 1.0)] was created before weaning. A 3-minute weaning process was initiated once normothermia was achieved. Mixed venous and arterial samples were obtained during CPB, weaning, and 10 minutes postbypass. Samples were assayed for [K+], [Ca++], glucose, pH, CPK-MB, and lactic acid levels. Hyperkalemia resulted in the generation of severe arrhythmias in all animals. During the immediate prewean period, there was a significant correlation between venous [K+] and pH (p < .01, r2 =.891). Arterial pH did not change during the weaning or post-CPB period, while venous pH declined significantly throughout the same period (7.35 +/- 0.75 to 7.20 +/- 0.17, p < .05). No other measured variables correlated with hyperkalemia. In summary, hyperkalemia caused a significant decline in venous pH evidenced in the early separation period, but had no effect on other variables. Therefore, measurement of venous pH may be an early marker indicating myocardial dysfunction and dysrhythmia.

Acidosis↗
PubMed2003

[Study on the anti-apopotosis induced by hypoxia/hypoglycemia and reoxygenation of panax notoginseng saponins in cultured rat hippocampal neurons].

OBJECTIVE: To study the inhibitory effects of Panax Notoginseng Saponins(PNS) on apoptosis induced by hypoxia/hypoglycemia and reoxygenation in cultured rat hippocampal neurons. METHOD: Apoptosis were measured by flow cytometry, intracellular free calcium concentration([Ca2+]i) was measured with confocal laser scanning microscopy, morphological changes and neuronal necrosis were observed with fluorescence microscope, and meanwhile the leakage of lactic dehydrogenase(LDH) was measured. RESULT: Hypoxia/hypoglycemia cultures for 5 hours and reoxygenation induced neuronal apoptosis and necrosis, and significantly increased neuronal [Ca2+]i and the leakage of LDH. The effects were increased with the extending time of reoxygenation. PNS has could significantly decrease the percentage of neuronal apoptosis and necrosis, and reduce neuronal [Ca2+]i and the leakage of LDH. CONCLUSION: PNS has inhibitory effect on neuronal apoptosis. This effect might be related to its effect of decreasing intracellular free calcium concentration.

Animals↗
PubMed2002

Combined carrier status of prothrombin 20210A and factor XIII-A Leu34 alleles as a strong risk factor for myocardial infarction: evidence of a gene-gene interaction.

Studies associating the prothrombin 20210G>A (FII 20210A), factor V Leiden (FVL), and factor XIII Leu34 (FXIII-A Leu34) alleles with myocardial infarction (MI) have yielded conflicting results. Complicated gene-gene interactions, small sample sizes, and heterogeneous genetic and environmental backgrounds may contribute to opposing findings. Simultaneous analysis of multiple gene variants in a large sample size from a genetically isolated population may overcome these weaknesses. Genotyping was performed in 500 MI patients and 500 control subjects from the genetically isolated Newfoundland population to determine the prevalence of the FII 20210A, FVL, and FXIII-A Leu34 variants and their association with MI. Gene-gene interactions were also analyzed. The prevalence of the FII 20210A allele was higher in MI patients (3.2%) than in control subjects (1.0%; P =.015). The FII 20210A allele was also 5.6-fold higher in MI patients younger than 51 years than in age-matched control subjects (P =.04). FVL showed 3.9-fold higher prevalence in young patients than in patients older than 50 years (P =.004) and 2.7-fold higher than in age-matched control subjects (P =.007). Furthermore, the prevalence of combined carriers of the FXIII-A L34 and FII 20210A alleles was 12-fold higher in MI patients than in control subjects (P =.002) and with 92% penetrance. There was disequilibrium of the FXIII-A Leu34 allele to MI patients carrying the FII 20210A allele as a genetic background. Based on our data, we determined that (1) the FII 20210A allele is a risk factor for MI, possibly important for early onset; (2) FVL may predispose for early-onset MI; (3) the FXIII-A Leu34 allele predisposes for MI in males only; however, (4) interaction between the FII 20210A and FXIII-A Leu34 alleles forms a synergistic coeffect that strongly predisposes for MI, placing combined carriers at high risk for MI.

5' Untranslated Regions↗
PubMed2002

Neuronal expression of fos protein in the forebrain of diabetic rats.

We sought to identify the areas that have altered neuronal activity within the hypothalamus of diabetic rats by mapping neuronal expression of c-fos protein (Fos) and Fos-related antigens. After a standard PAP immunocytochemical protocol, Fos-like immunoreactivity was observed in the paraventricular nucleus (PVN), supraoptic nucleus (SON), median preoptic area (MnPO), anterior hypothalamus (AH) and posterior hypothalamus (PH) of control (vehicle; n=6) and diabetic rats (Sprague-Dawley rats injected with STZ 65 mg/kg/ip 4 weeks prior to the experiment; n=6). Blood glucose levels were significantly elevated in the diabetic group (370+/-8 mg/dl) compared to control group (104+/-3 mg/dl). Diabetic rats had a significantly higher number of Fos-positive cells in PVN (2.5x), SON (7x) and MnPO (2x) compared to the control rats. However, diabetic rats had significantly fewer Fos-positive cells in the AH (0.3x) and no difference was observed in the PH between the diabetic and control rats. Despite the elevated number of Fos-positive cells in the diabetic rats, dehydration (water withdrawal for 24 h) or hypertonic challenge (1.5 ml of 0.1 M NaCl i.p. injection) produced a further increase in the number of Fos-positive cells in the PVN, SON and MnPO. Dehydration did not alter the number of Fos-positive cells in the AH or PH, but hypertonic challenge produced a significant increase in the Fos-positive cells in both the AH and PH of diabetic rats. This study demonstrates that: (1) there is increased basal neuronal activity in the PVN, SON and MnPO, a decrease in neuronal activity in the AH and no change in neuronal activity in the PH as indicated by Fos staining in diabetic rats; and (2) dehydration or hypertonic challenge produces a further increase in the number of Fos-positive cells in the PVN, SON, and MnPO which is comparable to control rats. These data support the conclusion that vasopressin producing neurons in the PVN and SON and autonomic areas within the lamina terminalis and hypothalamus are activated during diabetes and may contribute to the elevated levels of vasopressin and autonomic dysfunction during diabetes.

Animals↗
PubMed2002

An integrated view of the roles and mechanisms of heat shock protein gp96-peptide complex in eliciting immune response.

Heat shock protein (HSP) gp96, or grp94 is an endoplasmic reticular (ER) paralog of the cytosolic HSP90. Being abundant and non-polymorphic, gp96 plays significant roles in maintaining protein homeostasis in the secretory pathway. This "house-keeping" role of gp96 has now been overshadowed by the intriguing findings that gp96 modulates both the innate and adaptive components of the immune system. It has been found that, (i) gp96 is one of the major peptide binding proteins in the ER, (ii) gp96 interacts specifically with receptors including CD91 and possibly toll-like receptors (TLRs), on the surface of professional antigen presenting cells (APCs), (iii) interaction with APCs leads to re-presentation of gp96-chaperoned peptides to the major histocompatibility complex (MHC) molecules of APCs, (iv) direct access of gp96 to APCs triggers functional activation of APCs. In this review, we will examine each of these immunological attributes of gp96 critically. As experimentalists, we will also propose specific experiments to examine the argument that gp96, perhaps along with other members of HSP family, is the antigenic carrier for mediating cross priming of antigen-specific T lymphocytes in vertebrates.

Amino Acid Sequence↗
PubMed2002

Recurrent inguinal hernia: disease of the collagen matrix?

The aim of this study was to investigate the collagen matrix in recurrent inguinal hernias. Total ribonucleic acid (RNA) was extracted from skin fibroblasts of three groups (control group I = healthy skin; control group II = plain skin scar; recurrent inguinal hernia group = skin of recurrent inguinal hernias; each n = 5). Reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis were used to investigate the expression of procollagen type I/- III, MMP-1, and MMP-13 mRNAs. Both ratios of procollagen types I to III mRNAs and collagen types I to III were apparently decreased in the recurrent hernia group compared to those of both control groups (p < 0.01). Significant differences were caused by the increase of both procollagen type III mRNA and collagen type III protein synthesis. A concomitant increase of MMP-1 and MMP-13 mRNAs and proteins was also observed in the recurrent hernia group and showed significant differences compared to those of both control groups I and II, respectively (p < 0.01). In conclusion, the decreased ratio of collagen types I to III seems not only to be the result of a relative increase in the levels of type III procollagen mRNA but also may be the result of an increase of MMP-1 and MMP-13. The data of the present study strongly suggest recurrent inguinal hernias to be a disease of the collagen matrix and result in a clearer understanding of the underlying pathophysiology and may support specific therapeutic strategies in hernia surgery (e.g., surgical meshes).

Aged↗
PubMed2002

Peer influences and access to cigarettes as correlates of adolescent smoking: a cross-cultural comparison of Wuhan, China, and California.

BACKGROUND: Few studies have assessed the effects of access to cigarettes and peer influences on adolescent smoking in non-Western countries. Using samples characterized by two distinct cultural, social, and economic systems, this study evaluated the associations of friends' smoking and perceived access to cigarettes with adolescent smoking behavior in California and Wuhan, China. METHODS: Survey data were obtained from 5870 eighth-grade students in the Independent Evaluation of the California Tobacco Control Program and 6992 seventh- to ninth-grade students in the Wuhan Smoking Prevention Trial. Odds ratios for lifetime and 30-day smoking, according to friends' smoking and perceived access to cigarettes, were calculated for boys and girls in both samples and compared. RESULTS: California students were more likely than Wuhan students to have friends who smoked and to perceive easy access to cigarettes. The smoking prevalence was lower in Wuhan than in California, mainly due to the low smoking prevalence among Wuhan girls. Friends' smoking was strongly associated with smoking in both samples, and the strength of this association did not differ between the two cultures. Access to cigarettes was associated with a higher risk of lifetime smoking in both cultures and a higher risk of past 30-day smoking in California only. CONCLUSIONS: Despite divergent tobacco control policy enforcement, social structures, and cultural contexts, similarities exist between Wuhan and California. The findings suggest support for adapting a social-influences-based smoking prevention program developed in the United States to the culturally specific needs of youth in Wuhan, China.

Adolescent↗
PubMed2002

[Studies on lipase-catalyzed synthesis of ethylglucoside lactate in non-aqueous phase].

Ethylglucoside lactate, a novel Alpha-Hydroxy Acids Derivative, was synthesized by transesterification in non-aqueous phase using immobilized lipase as biocatalyst. Based on the studies of the factors effecting initial rate and conversion under atmospheric pressure (solvent, acyl donor, different immobilized lipase, substrate concentration, enzyme concentration and temperature), the results show that solvent-free medium using butyllactate as acyl donor is suitable to the ester synthesis. The reaction conditions have been optimized as the following: the amount of enzyme = 75 g/L, the ethylglucoside concentration = 0.4 mol/L, 70 degrees C, 200 r/min, 50 h, which the conversion was 71%. A 90% conversion and a 60.7 mmol.L-1.h-1 initial rate can be obtained under reduced pressure, which the conditions are enzyme 75 g/L, ethylglucoside 0.35 mol/L, 65 degrees C, 200 r/min and 40 h. The product purified by extraction and SIO2 chromatography was identified by infrared spectroscopy and 1H NMR.

Candida↗
PubMed2002

Effects of increasing FiO2 on venous saturation during cardiopulmonary bypass in the swine model.

Adequacy of perfusion during cardiopulmonary bypass (CPB) is dependent on nutrient delivery and waste removal from the tissue. A recent study showed that over 75% of cardiopulmonary bypass procedures are completed using continuous venous saturation (SvO2) monitoring. The purpose of this study was to determine the effect of changing FiO2concentration on SvO2. A total of eight mixed gender 45-kg swine were placed on CPB under moderate hypothermic conditions. Animals were divided evenly into two groups: Experimental, where FiO2 was increased to 100% and blood flow decreased to an SvO2 level of prechange in FiO2, and Control, where the same condition was created except no change in blood flow. Variables measured include hemodynamic, blood gas, intramyocardial pH, and lactic acid concentrations. In the experimental group, percentage change of blood flow was decreased from baseline 28.4% +/- 12.5% (p < .005) as well as percentage change of oxygen delivery 23.9% +/- 14.7% (p < .005). Systemic venous saturation percentage change was increased in both the experimental 14.4% +/- 6.8% (p < .05) and control 11.2% +/- 7.1% (p < .05) groups. Jugular venous saturation percentage change was decreased in the experimental group 7.8% +/- 6.34% (p < .02), but not in the control animals. Myocardial venous saturation percentage change decreased in the experimental group to 3.73% +/- 8.34% (p < .004). Experimental manipulation, however, did not significantly change jugular lactic acid concentrations or intramyocardial pH values. In conclusion, these results suggest that decreased blood flow adjusting for increased SvO2 associated with high PaO2 did not result in significant reduction of adequacy of perfusion markers for organs studied.

Animals↗