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Biomedical subjects

X Z Huang

Publications and source records attributed to X Z Huang.

At least 19 recordsLinked to original sources
PubMed2002

In vivo accumulation of Broad bean wilt virus 2 VP37 protein and its ability to bind single-stranded nucleic acid.

The VP37 protein encoded by the RNA2 of Broad bean wilt virus 2 (BBWV2) was overexpressed in Escherichia coli. The protein was purified and a polyclonal antibody specific for the protein was produced. Time course studies by Western blot assays in BBWV2-infected Chenopodium quinoa leaves showed that the VP37 protein was present in cells of the inoculated leaves by 12 h post inoculation and in cells of systemically-infected leaves by 2 days post inoculation. The protein was able to accumulate to a high level in infected leaves at the late infection stage. Gel retardation and UV cross-linking assays demonstrated that the VP37 protein bound preferentially single-stranded (ss) RNA and DNA in a non-sequence-specific manner. The VP37 protein-RNA complex was stable in solutions containing less than 400 mM NaCl, but became fully dissociated in the solutions containing 800 mM NaCl. Sequence analysis of the VP37 protein and its ability to bind ssRNA and ssDNA suggest that the protein may play a role similar to the movement proteins reported for other plant viruses.

Blotting, Western↗
PubMed2000

Differential bacterial survival, replication, and apoptosis-inducing ability of Salmonella serovars within human and murine macrophages.

Salmonella serovars are associated with human diseases that range from mild gastroenteritis to host-disseminated enteric fever. Human infections by Salmonella enterica serovar Typhi can lead to typhoid fever, but this serovar does not typically cause disease in mice or other animals. In contrast, S. enterica serovar Typhimurium and S. enterica serovar Enteritidis, which are usually linked to localized gastroenteritis in humans and some animal species, elicit a systemic infection in mice. To better understand these observations, multiple strains of each of several chosen serovars of Salmonella were tested for the ability in the nonopsonized state to enter, survive, and replicate within human macrophage cells (U937 and elutriated primary cells) compared with murine macrophage cells (J774A.1 and primary peritoneal cells); in addition, death of the infected macrophages was monitored. The serovar Typhimurium strains all demonstrated enhanced survival within J774A.1 cells and murine peritoneal macrophages, compared with the significant, almost 100-fold declines in viable counts noted for serovar Typhi strains. Viable counts for serovar Enteritidis either matched the level of serovar Typhi (J774A. 1 macrophages) or were comparable to counts for serovar Typhimurium (murine peritoneal macrophages). Apoptosis was significantly higher in J774A.1 cells infected with serovar Typhimurium strain LT2 compared to serovar Typhi strain Ty2. On the other hand, serovar Typhi survived at a level up to 100-fold higher in elutriated human macrophages and 2- to 3-fold higher in U937 cells compared to the serovar Typhimurium and Enteritidis strains tested. Despite the differential multiplication of serovar Typhi during infection of U937 cells, serovar Typhi caused significantly less apoptosis than infections with serovar Typhimurium. These observations indicate variability in intramacrophage survival and host cytotoxicity among the various serovars and are the first to show differences in the apoptotic response of distinct Salmonella serovars residing in human macrophage cells. These studies suggest that nonopsonized serovar Typhimurium enters, multiplies within, and causes considerable, acute death of macrophages, leading to a highly virulent infection in mice (resulting in death within 14 days). In striking contrast, nonopsonized serovar Typhi survives silently and chronically within human macrophages, causing little cell death, which allows for intrahost dissemination and typhoid fever (low host mortality). The type of disease associated with any particular serovar of Salmonella is linked to the ability of that serovar both to persist within and to elicit damage in a specific host's macrophage cells.

Animals↗
PubMed2000

Fatal bilateral chylothorax in mice lacking the integrin alpha9beta1.

Members of the integrin family of adhesion receptors mediate both cell-cell and cell-matrix interactions and have been shown to play vital roles in embryonic development, wound healing, metastasis, and other biological processes. The integrin alpha9beta1 is a receptor for the extracellular matrix proteins osteopontin and tenacsin C and the cell surface immunoglobulin vascular cell adhesion molecule-1. This receptor is widely expressed in smooth muscle, hepatocytes, and some epithelia. To examine the in vivo function of alpha9beta1, we have generated mice lacking expression of the alpha9 subunit. Mice homozygous for a null mutation in the alpha9 subunit gene appear normal at birth but develop respiratory failure and die between 6 and 12 days of age. The respiratory failure is caused by an accumulation of large volumes of pleural fluid which is rich in triglyceride, cholesterol, and lymphocytes. alpha9(-/-) mice also develop edema and lymphocytic infiltration in the chest wall that appears to originate around lymphatics. alpha9 protein is transiently expressed in the developing thoracic duct at embryonic day 14, but expression is rapidly lost during later stages of development. Our results suggest that the alpha9 integrin is required for the normal development of the lymphatic system, including the thoracic duct, and that alpha9 deficiency could be one cause of congenital chylothorax.

Animals↗
PubMed2000

The prevalence of NIDDM and IGT and related factors among residents in some areas of Hubei Province, China.

The epidemiological survey of prevalence of NIDDM (non-insulin dependent diabetes mellitus) and IGT(impaired glucose tolerance) was conducted among 9450 residents aged 25-70 in some areas of Hubei Province, China. The results show that NIDDM and IGT prevalences are 2.62% and 4.48%, respectively. There is no significant difference between male and female (P > 0.05). The NIDDM prevalence in cities is slightly higher than that in countryside, but the difference is not significant (P > 0.05). However, the IGT prevalence in city is significantly higher than that in countryside (P < 0.01). The prevalence of both NIDDM and IGT is increasing along with the age of the population. It is also significantly related to the family history of NIDDM, hypertension, and high body mass index (BMI). By using stepwise logistic regression to analyse the risk factors of NIDDM, age (OR = 1.86), BMI(OR = 2.69), family history (OR = 2.84) and hypertension (OR = 2.23) entered the model (significance level is alpha = 0.05).

Adult↗
PubMed2000

[The study of the nasal airway reactivity in specific nasal provocation test].

OBJECTIVE: To explore efficient evaluation method for specific nasal provocation test(SNPT) and to observe the pathogenic process and patho-physiological changes of allergic rhinitis. METHOD: 30 patients with perennial allergic rhinitis(patients group) and 14 normal adults(controls group) were challenged unilaterally with the Coca's solution and/or the solution for allergen extracts. The nasal resistance variations in all subjects were monitored with active anterior rhinomanometry and the nasal symptoms were observed. RESULT: The symptoms of nasal stiffness, sneezing and rhinorrhea appeared in most patients between 0.5 and 3 minutes after provocation. The ratio of continual sneezes above 5 in patients group(83.3%) was significantly higher than in controls group (21.4%) (P < 0.01). The increased ratio of total nasal resistance and unilaterally-challenged nasal resistance were significantly higher in patients group than in controls group (P < 0.05) and no difference between coca's solution in patients group and controls group. CONCLUSION: Positive SNPT was indicated if obvious nasal symptoms appeared and the unilaterally-challenged nasal resistance increased 100% as well as the total nasal resistance increased 40% after SNPT.

Adolescent↗
PubMed1999

Magnetic resonance imaging of the upper airway in obstructive sleep apnea before and after oral appliance therapy.

OBJECTIVE: To determine the mechanism by which an oral appliance may be used to treat obstructive sleep apnea syndrome (OSAS). METHODS: Eleven OSAS patients (8 males and 3 females) were involved in the study. Mean age was 52.2 +/- 10.6 years; height was 166.6 +/- 7.2 cm, and weight was 75.6 +/- 9.3 kg; body mass index (BMI) was 27.2 +/- 2.9 kg/m2. Each patient underwent magnetic resonance imaging (MRI) and polysomnography before and after oral appliance therapy. Pharyngeal changes were measured and compared with the variation in sleep parameters. Also, Pearson's correlation and multiple linear regression were performed to investigate the relationship of sleep parameters and MRI items. RESULTS: Through oral appliance therapy, the sleep disorder decreased. Apnea/hypopnea index (AHI) decreased from 44.6 +/- 21.5 to 9.6 +/- 6.3 per hour of sleep. Lowest oxygen desaturation rose from 71.4 +/- 15.0% to 82.0 +/- 7.7%. Meanwhile, the upper airway increased at most levels, and especially at oropharynx. As measured by the correlation and regression analysis, the AHI changes had a negative association with tongue volume (R = -0.5730) and a positive association with the area alternation of high oropharynx (R = 0.5823); the change of the lowest oxygen desaturation (SaO2%) was positively associated with whole airway volume (R = 0.6554). CONCLUSION: The oral appliance works by enlarging the upper airway morphology and keeping the airway open, mainly at the back of soft palate. The effect of the oral appliance is associated with the degree of enlargement of the high oropharynx. Those who have a small tongue and a large pharynx may expect to have good results with the use of the oral appliance.

Female↗
PubMed1999

Orthognathic surgery correction of mandibular hypoplasia accompanying obstructive sleep apnea syndrome.

OBJECTIVE: To examine the surgical correction methods for treating cases of severe mandibular hypoplasia accompanying obstructive sleep apnea syndrome (OSAS). METHODS: Sixteen cases of severe mandibular hypoplasia were studied in which OSAS was documented by polysomnography (PSG) and cephalometric study. The obstructive site was at the base of the tongue. Surgical procedures such as temporomandibular joint (TMJ) reconstruction and bimaxillary, chin, and hyoid bone advancement were performed to improve each patient's profile, function, and occlusion, and to treat the OSAS. RESULTS: There were great improvements in patient's sleep and daytime quality of life. The pre- and postoperative changes of most PSG values and some cephalometric values (SNB, PAS) were statistically significant. CONCLUSIONS: Severe mandibular hypoplasia can cause not only abnormalities in profile and occlusion but also OSAS. The evaluation of OSAS and its treatment effects depend on PSG. It is also very important to confirm the obstructive site in the upper airway by cephalometric study and fiberoptic endoscopy. Orthognathic surgery procedures can advance the maxillary, chin, and hyoid bone, and expand the upper airway simultaneously. These procedures can treat OSAS. Cases of TMJ ankylosis with OSAS should be treated step by step.

Adolescent↗
PubMed1998

Mutation in the peb1A locus of Campylobacter jejuni reduces interactions with epithelial cells and intestinal colonization of mice.

Campylobacter jejuni is one of the leading causes of bacterial diarrhea throughout the world. We previously found that PEB1 is a homolog of cluster 3 binding proteins of bacterial ABC transporters and that a C. jejuni adhesin, cell-binding factor 1 (CBF1), if not identical to, contains PEB1. A single protein migrating at approximately 27 to 28 kDa was recognized by anti-CBF1 and anti-PEB1. To determine the role that the operon encoding PEB1 plays in C. jejuni adherence, peb1A, the gene encoding PEB1, was disrupted in strain 81-176 by insertion of a kanamycin resistance gene through homologous recombination. Inactivation of this operon completely abolished expression of CBF1, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. In comparison to the wild-type strain, the mutant strain showed 50- to 100-fold less adherence to and 15-fold less invasion of epithelial cells in culture. Mouse challenge studies showed that the rate and duration of intestinal colonization by the mutant were significantly lower and shorter than with the wild-type strain. In summary, PEB1 is identical to a previously identified cell-binding factor, CBF1, in C. jejuni, and the peb1A locus plays an important role in epithelial cell interactions and in intestinal colonization in a mouse model.

Animals↗
PubMed1998

Physical limitations on Salmonella typhi entry into cultured human intestinal epithelial cells.

Kinetic studies of Salmonella typhi invasion of INT407 cells at different multiplicities of infection (MOIs) have revealed a strict physical limitation on S. typhi entry at MOIs of >/=40. Staining of infected monolayers to distinguish intracellular from extracellular bacteria revealed that all monolayer cells are susceptible to infection and that internalized bacteria are typically contained in one to three separate clusters per cell during the first 60 min. Scanning and transmission electron microscopic analyses of time course-infected monolayers showed that at early times postinfection, bacteria bind to shortened, coalesced microvilli in one to three focal aggregate structures per host cell surface. As reported previously for S. typhimurium, focal aggregates progress to conical membrane ruffles that appear to engulf one or a few centrally contained S. typhi cells by a macropinocytic process, which enhanced the entry of simultaneously added Escherichia coli HB101 about 30-fold. Additionally, kinetic studies showed that at an MOI of approximately 400, maximal S. typhi entry is virtually completed within 30 to 35 min. Monolayers pretreated with S. typhi for 30 min to saturate the entry process were severely reduced in the ability to internalize subsequently added kanamycin-resistant strains of S. typhi or S. typhimurium, but E. coli HB101(pRI203) expressing the cloned Yersinia inv gene was not reduced in entry. In invasion inhibition assays, anti-beta1 integrin antibodies markedly reduced E. coli HB101(pRI203) invasion efficiency but did not reduce S. typhi entry. Collectively, these data provide direct physical and visual evidence which indicates that S. typhi organisms are internalized at a limited number (i.e., two to four) of sites on host cells. S. typhi and S. typhimurium likely share INT407 cell entry receptors which do not appear to be members of the beta1 integrin superfamily.

Binding, Competitive↗
PubMed1996

Inactivation of the integrin beta 6 subunit gene reveals a role of epithelial integrins in regulating inflammation in the lung and skin.

The integrin alpha v beta 6 is only expressed in epithelial cells. In healthy adult epithelia, this receptor is barely detectable, but expression is rapidly induced following epithelial injury. Mice homozygous for a null mutation in the gene encoding the beta 6 subunit had juvenile baldness associated with infiltration of macrophages into the skin, and accumulated activated lymphocytes around conducting airways in the lungs. Beta 6-/- mice also demonstrated airway hyperresponsiveness to acetylcholine, a hallmark feature of asthma. These results suggest that the epithelial integrin alpha v beta 6 participates in the modulation of epithelial inflammation. Genetic or acquired alterations in this integrin could thus contribute to the development of inflammatory diseases of epithelial organs, such as the lungs and skin.

Alopecia↗
PubMed1995

A point mutation in the integrin beta 6 subunit abolishes both alpha v beta 6 binding to fibronectin and receptor localization to focal contacts.

The integrin alpha v beta 6 was initially identified from primary cultures of airway epithelial cells. This integrin is expressed in bronchiolar and alveolar epithelium during development and in settings of injury and/or inflammation and mediates attachment of epithelial cells to fibronectin and tenascin. Like other integrins, this receptor localizes to structures called focal contacts in cells plated on appropriate ligands. In the present study, we produced a mutant beta 6 cDNA (beta 6m) containing a single substitution of Asp140 with Ala and transfected mutant (or wild-type) beta 6 cDNA into the human colon carcinoma cell line SW480. In parallel, we used cDNAs truncated just proximal to the transmembrane domain to generate secreted forms of mutant alpha v beta 6 in Chinese hamster ovary (CHO) cells. The mutant beta 6, like the wild type, formed heterodimers with human alpha v that were expressed on the cell surface of SW480 cells and secreted by CHO cells. Secreted alpha v beta 6 containing this point mutation did not bind to fibronectin-Sepharose. Furthermore, in contrast to wild-type beta 6, the mutant form did not allow SW480 cells to bind to fibronectin in the presence of beta 1-blocking antibody and did not localize to focal contacts. Our results confirm that the Asp140 of beta 6, like the corresponding residues in beta 1 (Asp130) and beta 3 (Asp119), is critical for interactions of alpha v beta 6 with ligand, and also suggest that ligand binding to alpha v beta 6 is necessary for localization of this receptor to focal contacts.

Alanine↗
PubMed1994

[Management of nocturnal nasal mask continuous positive airway pressure in central hypoventilation in patients with respiratory diseases].

The effect of nasal mask CPAP administered during night in four central hypoventilation patients with various causes were investigated. On the basis of their histories, specific clinical manifestations, cranial CT and MRI, cerebral angiography and polysomnography. The patients (three males and one female) are diagnosed as primary alveolar hypoventilation and central hypoventilation, the later mainly caused by the compression of bulbar respiratory centre due to congenital deformity of right vertebral artery and deformity of foramen magnum. In order to assess the severity of nocturnal hypoventilation and blood oxygen level of the patients, polysomnography was taken before treatment, during 2L/min of oxygen via nasal tube and CPAP ventilation. Only oxygen administration did not ameliorate hypoventilation episodes and hypoxemia, lowest SaO2 is less than 50% on four patients, hypoventilation index is greater than 20 times/hour in three patients and 6.4 in a patient. Applying CPAP with the pressure fixed to 6-12 cm H2O can significantly improve hypoventilation index and hypoxemia with lowest SaO2 more than 70% (P < 0.001) and hypoventilation index less than 7 (P < 0.01). We conclude that nocturnal nasal mask CPAP is an effective treatment for central hypoventilation.

Adult↗
PubMed1992

[Synchronous spectrofluorimetry for simultaneous determination of riboflavin and pyridoxine and its application in multivitamin preparations].

A new method for the simultaneous determination of riboflavin and pyridoxine by synchronous spectrofluorimetry is described. The measurement was carried out in a buffer solution of pH 7 with delta lambda = 58 nm for synchronous scanning. Under the experimental conditions two peaks appeared at 526 nm and 389 nm in the obtained synchronous fluorescence spectrum, corresponding to riboflavin and pyridoxine, respectively. This method was proved to be simple and specific. The fluorescence relative intensity is linearly related with concentration over the range of 0-1 microgram/ml and 0-1.5 micrograms/ml for riboflavin and pyridoxine, respectively. The detection limit was 0.5 ng/ml for riboflavin and 1 ng/ml for pyridoxine. The relative errors of the measurements were less than 5% for artificial samples. The proposed method has been applied to the analyses of riboflavin and pyridoxine in three kinds of commercial multivitamin preparations. The obtained synchronous spectra of multivitamin preparations coincided with those of the mixed standard solution of riboflavin and pyridoxine. Recoveries of 93.5-105.7% were obtained.

Drug Combinations↗
PubMed1991

An experimental study of lung lesions caused by extracellular enzyme of Streptomyces thermohygroscopicus.

Rabbits and rats were infected intratracheally with extracellular enzyme of Streptomyces thermohygroscopicus (H9-4) by only one exposure, and lesions of the lung developed including mononuclear macrophage infiltration as well as bronchitis and vasculitis. The obvious damages in type I pneumocytes, endothelial cells of capillaries and arterioles in the lung were observed by electron microscopy. Immunofluorescent histochemistry examination revealed exudation of plasma fibronectin which might play an important role during the process of lesion repairing in lung. The experiment also confirmed that extracellular enzyme of Streptomyces thermohygroscopicus might directly damage the lung tissue. These experimental data may serve as valuable reference for studying the etiology and pathogenesis of farmer's lung disease.

Animals↗
PubMed1991

[Nasal continuous positive airway pressure therapy in obstructive sleep apnea syndrome].

Sixteen patients (male: 14, female: 2, 41-72 yrs, mean 57.5 yrs) with OSAS were treated by nCPAP in our hospital since 1987. Respiratory disturbance index ranged from 16.5 to 83.1. The longest apnea duration was 35.0-120.5 seconds before the treatment. Two patients were treated with Sleep Easy III (Respironics Inc.) and others with a home made instruments. nCPAP was set at a pressure of 5 to 10 cm H2O. 12 patients (75%) tolerated the device but 4(25%) did not. Polysomnographic parameters before and after nCPAP therapy were compared. The longest apnea duration was 63.1 +/- 23.5 to 40.9 +/- 27.4 seconds (P less than 0.001) and the lowest saturation oxygen was 55.1 +/- 20.4% to 71.4 +/- 18.6% (P less than 0.05). The sleep structure improved but not significant statistically. One of them used nCPAP at home for more than two. years and showed a good long term effect. We concluded that nCPAP is an effective and safe treatment for OSAS. However, patients may be uncomfortable because of the wearing of the nasal mask during sleep.

Adult↗
PubMed1991

[Clinical use of polysomnography (PSG)].

The clinical diagnoses in 695 cases using PSG were analysed. The results are as follows: Obstructive sleep apnea syndrome (OSAS) in 482 cases (69.4%), chronic obstructive pulmonary diseases with nocturnal hypoxemia in 25 cases (3.6%), epilepsy in 31 cases (4.5%), other sleep disorders in 5 cases (0.7%), and essentially normal in 152 cases (21.9%). Some parameters of PSG in 65 cases with OSAS and those in 2 cases before and after treatment were analysed. It is emphasized that PSG is using for diagnosis of different types of OSAS with appraisable seriousness and of other related sleep disorders. The method and indications of PSG were discussed.

Electroencephalography↗
PubMed1990

[A screening study of snorers with or without sleep apnea].

There are 76 cases of snorers with or without sleep apnea by screening study using ZD2Apnea Monitor or/and Ohmeda 3700 Pulse Oximeter. It is compared with polysomonographic recording. The sensitivity and specificity of screening study are 96.4% and 95.2% respectively. The advantage and disadvantage of these two methods are evaluated. It is suggested that ZD2Apnea Monitor is a simple, useful and cheap screening test for snorers with or without sleep apnea. It is suitable to clinical use.

Adolescent↗