Search PubMed⌕ Search

Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 577 records · Page 32Linked to original sources
PubMed1997

Protective effects of interleukin-11 in a murine model of ischemic bowel necrosis.

The present study examined the effect of interleukin-11 (IL-11) in a murine model of bowel ischemia (BI). Prophylactic IL-11 administration in BI mice (induced by occluding the superior mesenteric artery for 90 min) was associated with significantly decreased morbidity and mortality. IL-11-treated mice demonstrated rapid recovery of intestinal mucosa as evidenced by an increase in mitotic activity and suppression of apoptosis in intestinal crypt cells as well as increased peripheral platelet and leukocyte counts primarily due to an increase in peripheral lymphocyte number in BI mice. In contrast to vehicle-treated mice, which uniformly developed thrombocytopenia after ischemic injury, no IL-11-treated BI mice developed thrombocytopenia during the experimental period. These data suggest a role for IL-11 in the treatment of gastrointestinal mucosal diseases due to a wide variety of causative injuries.

Animals↗
PubMed1997

Pulsatile stretch stimulates superoxide production and activates nuclear factor-kappa B in human coronary smooth muscle.

There is increasing evidence that oxidative stress is of pathophysiological importance in cardiovascular disease. Mechanical forces such as pulsatility may also contribute. Using human coronary artery smooth muscle cells (HCAS), we tested the hypothesis that stretch-induced cell proliferation is associated with oxidative stress. Stretch induced DNA synthesis in HCAS, and this was prevented by the antioxidants N-acetylcysteine and pyrrolidinedithiocarbamate (PDTC). Pulsatile stretch also increased superoxide production from HCAS in a time- and stretch dependent manner. Stretch-induced superoxide production was inhibited by diphenyleneiodoniumchloride, an NADPH oxidase inhibitor, and p-chloromercuriphenylsulfonic acid, an NADH oxidase inhibitor, but not by the xanthine oxidase inhibitor oxypurinol or the cyclooxygenase inhibitor indomethacin. In electrophoretic mobility shift assays, tumor necrosis factor-alpha activated nuclear factor-kappa B (NF-kappa B) with a peak at approximately 3 hours, whereas pulsatile stretch showed sustained activation during stimulation for up to 24 hours. The sustained activation of NF-kappa B was abolished by cotreatment with N-acetylcysteine or PDTC. Furthermore, treatment of HCAS with antisense p65 and p50 oligodeoxynucleotides of NF-kappa B inhibited stretch-induced DNA synthesis. We propose that pulsatile stretch increases oxidative stress and, in turn, promotes DNA synthesis via NF-kappa B in cultured human coronary artery smooth muscle cells.

Cells, Cultured↗
PubMed1997

The incidence of false-positive cultures for Mycobacterium tuberculosis.

The frequency of false-positive cultures for Mycobacterium tuberculosis due to cross-contamination has been difficult to determine because of the lack of specific strain markers. Isolates collected prospectively over 5 yr from a municipal health department laboratory underwent DNA fingerprinting using the IS6110 and pTBN12 sequences. We reviewed the clinical and laboratory records of all isolates that had matching DNA fingerprints and were processed within 42 d of each other; 8 isolates were classified as probable or definite false-positives, representing 4.0% (8/199) of the culture-positive patients. A convenience sample of 42 isolates from three other mycobacterial laboratories also underwent DNA fingerprinting, and five (12%) were found to be definite or probable false-positives. Cross-contamination during initial processing of specimens was the most common source of false-positive cultures. The source of cross-contamination for three false-positive cultures was a laboratory proficiency survey specimen containing strain H37Ra. Ten of the 13 patients were misdiagnosed as having tuberculosis, and seven received unnecessary multidrug treatment. Clinicians should be aware of the potential for false-positive cultures for M. tuberculosis, and mycobacteriology laboratories need to carefully review procedures to minimize this occurrence. DNA fingerprinting provides a valuable tool for the study of false-positive cultures.

Bacteriological Techniques↗
PubMed1997

DNA fingerprinting with two probes decreases clustering of Mycobacterium tuberculosis.

DNA fingerprinting of Mycobacterium tuberculosis is used to study the epidemiology of tuberculosis, but the specificity of the widely used IS6110 technique has not been validated. Isolates from Denver, Colorado from December 1988 through June 1994 were fingerprinted with the IS6110 technique. Available records were reviewed for patients whose isolates were within IS6110-defined clusters, and these isolates were fingerprinted with an independent technique (pTBN12). Of 189 isolates, 86 (46%) were in IS6110-defined clusters. Clustering was inversely related to the number of copies of IS6110, ranging from 12 of 12 (100%) to 37 of 48 (77%) and 37 of 129 (29%) for isolates having one, two to five, and more than five copies (p < 0.001). Of the 86 isolates clustered with the IS6110 technique, 35 (41%) had unique pTBN12 fingerprints. Discordant results with the two fingerprinting techniques were more common among isolates having five or fewer copies of IS6110. Epidemiologic links were identified among four of 35 (11%) patients whose isolates had discordant fingerprinting results, as compared with 40 of 51 (78%) of those whose isolates matched by both IS6110 and pTBN12. DNA fingerprinting with the IS6110 technique was not a specific marker of DNA clonality, particularly among isolates having fewer than five copies of IS6110. The use of a supplemental DNA fingerprinting technique decreased clustering and improved the correlation between the transmission links predicted by molecular techniques and epidemiologic investigation.

Cluster Analysis↗
PubMed1997

Chest radiographic findings in patients with tuberculosis with recent or remote infection.

To determine if chest radiographic findings differ in adult tuberculosis patients with recent and remote infection, we reviewed the chest radiographs of 103 patients with tuberculosis in Los Angeles and performed RFLP analyses of their Mycobacterium tuberculosis isolates. Patients whose isolates had identical or closely related RFLP patterns were considered a "cluster." Most patients in large clusters (more than seven patients) had tuberculosis from recent infection, whereas most unclustered patients had tuberculosis from remote infection. Mediastinal adenopathy or pleural effusions were classified as typical of recent infection, and upper lobe infiltrates, cavitation, or fibrosis were classified as characteristic of remote infection. Radiographic patterns were typical of remote infection in 62% of patients and were characteristic of recent infection in 23% of patients. The distribution of these radiographic patterns was similar in clustered and unclustered patients, both with or without human immunodeficiency virus (HIV) coinfection. However, mediastinal adenopathy and pleural effusions were significantly more common in HIV-infected patients. We conclude that: (1) chest radiographic findings in adults with tuberculosis of recent infection are similar to those in patients with remote infection; (2) the distinctive chest radiographic findings in HIV-infected patients with tuberculosis are not due to an increased frequency of recent infection.

AIDS-Related Opportunistic Infections↗
PubMed1997

In vivo gene delivery to the pulmonary circulation in rats: transgene distribution and vascular inflammatory response.

Although gene delivery to the pulmonary circulation has both experimental and therapeutic potential, the delivery methods, distribution of transgene, and subsequent inflammatory response have been poorly characterized to date. To address these issues, we utilized a 0.76-mm OD (outside diameter) end hole catheter inserted into the internal jugular vein of adult Sprague-Dawley rats, directing the tip into a pulmonary capillary wedge position. We then compared infusion of polycationic lipid:DNA complexes to replication-defective adenovirus with respect to magnitude and distribution of transgene expression using either chloramphenicol acetyltransferase (CAT) or human placental alkaline phosphatase (hpAP) reporter genes. Both lipid:DNA and adenovirus resulted in detectable transgene expression, though maximum lung CAT activity using lipid (gamma AP-DLRIE/DOPE) was approximately 2% of maximum activity using adenovirus (Ad-CAT). Further characterization of expression after transfection with 10(8) pfu (plaque forming units) of Ad-CAT demonstrated persistence of transgene for at least 14 days (lung CAT activity 27% of maximum). Alkaline phosphatase staining demonstrated that both large and small pulmonary arteries as well as the alveolar wall expressed transgene. Although little inflammatory response was detected in conduit arteries, a predominantly mononuclear cell infiltrate surrounded small pulmonary arteries as well as the alveolar spaces in transfected areas of lung. We conclude that percutaneous catheter-mediated gene delivery to the pulmonary circulation in rats using non-viral and viral vectors is feasible. Although an inflammatory response to first generation replication-defective adenovirus was detected, it appeared to be largely restricted to the distal pulmonary circulation and airspace. This technique should prove useful for investigations requiring overexpression of novel genes in the pulmonary artery wall, and could ultimately be used to develop gene-based therapies for pulmonary vascular diseases.

Adenoviridae↗
PubMed1997

A general enzyme immunoassay for the licorice root component contained in traditional Chinese medicines.

The development and application of a new enzyme immunoassay for general assay of the Glycyrrhizae radix (GR) component in Chinese traditional medicines is described. Three commercial GR-based medicines, Tohoku kanzo (GRTK), Seihoku Kanzo (GRSEK) and Sinkyo kanzo (GRSK) were used as GR specimens. Anti-GRSK serum was elicited from rabbits immunized with GRSK fragments. The presence of common proteins as specific antigens of GR was first established by Western blot analysis of extracts of GRSK, GRSEK or GRTK using anti-GRSK. The specific antigens were applied to develop an ELISA for the assay of GR extract. Anti-GRSK was put in competition with a sample or standard GR extract and immobilized GRSK components in microtiter plate wells. The proportion of antibody binding to the solid-phase GRSK component was detected using an enzyme-labeled second antibody. The ELISA method was specific to GRSK extract and showed low sensitivity for the assay of GRTK extract. The technique of selected antibody enzyme immunoassay (SAEIA) was applied to develop a sensitive general assay method. Solid-phase GRTK extract, rather than immobilized GRSK extract, was used in the SAEIA. The SAEIA possessed the same quantitative working range of between 1 and 100 micrograms/ml for the assay of each extract of GRTK, GRSK and GRSEK. The SAEIA was successful in the detection and quantitative measurement of GR component contents in Chinese traditional medicines.

Animals↗
PubMed1997

[The adaptive changes in vascular endothelial cell and resistance to frostbite in cold acclimated rats].

Several functions of vascular endothelial cells (VEC) were investigated in rats acclimated to cold (CA) and with frostbitten feet. The results indicated that in CA rats, the number of endothelial cells in circulatory blood and the contents of 6-keto -PGF1 alpha and TXB2 in plasma were markedly higher, the activity of serum angiotensin I converting enzyme (ACE) was lower, compared with those in rats non-acclimated to cold (NCA), whereas T/P ratio of the two groups was close to each other. After the rats were frostbitten, those parameters in NCA group increased sharply except for a decrease in ACE activity. But in CA group, those parameters decreased temporarily or did not change obviously and the tissue survival area (TSA) significantly increased. The above findings suggest that the adaptive changes in increase of metabolic turnover rate and function of VEC after cold acclimation may be beneficial to the body to enhance the resistance to frostbite and repairing ability.

6-Ketoprostaglandin F1 alpha↗
PubMed1997

[Effect of frostbite under hypoxia on microcirculatory perfusion in rats].

Changes of microcirculatory perfusion in rats following cold injury of right hind leg under hypoxia were investigated. Male Wistar rats weighing 200 +/- 20 g were randomly divided into three groups: frostbite at normoxia (FN) group; frostbite during acute hypoxia (4 h at 6000 m simulated altitude, FAH) group and frostbite during hypoxia after acclimation (exposure to hypoxia at 6000 m, 4 h daily for 4 weeks, FHAC) group. The results showed that the microcirculatory perfusion of both hind legs decreased markedly in FN after cold injury. It suggests that the frostbite damage can affect microcirculatory perfusion of another leg besides the region of frostbite. The fall of microcirculatory perfusion before freezing in FAH group indicated that there was a compensatory blood redistribution during acute hypoxia. The changes of microcirculatory perfusion in FAH group post-freezing indicated that acute hypoxia can aggravate the frostbite damage. The microcirculatory perfusion of FHAC group pre-freezing was significantly lower than that of FN and FAH group, and after freezing the perfusion of frostbitten leg in FHAC group was significantly lower than that in FN group, suggesting that hypoxia acclimation may cause disturbance of microcirculation and worsen the frostbite damage at high altitude.

Acclimatization↗
PubMed1997

[Matching study of lung function and respiratory symptoms in ex-dust exposure miners].

The lung function tests and respiratory symptom investigations were carried out on 156 pairs of ex-dust exposure miners and control workers according to match designing method. The matching was based on age, height, weight and smoking habit. The result showed that ex-dust exposure miners had higher frequency of abnormal lung function than that of control workers. Compared with control workers, the prevalence of respiratory symptoms and the incidence of chronic bronchitis were higher in ex-dust exposure miners.

Bronchitis↗
PubMed1997

[Experimental study on prevention of pneumoconiosis complicating with tuberculosis by Mycobacterium vaccae].

OBJECTIVE: To explore the role of Mycobacterium vaccae in prevention of pneumoconiosis complicating with tuberculosis. METHOD: Mycobacterium vaccae was injected into rats which had been exposed to quartz for 2 weeks, and H37Rv was injected into their tail veins 1 month later. All the rats were killed 3 months later. Indexes for evaluation in the study included tuberculous lesion pathological change index, Mycobacterium tuberculosis culture in a fixed amount in lung tissues, count of Mycobacterium tuberculosis and histopathological changes in alveolar macrophages. RESULT: Tuberculous lesion pathological change index, Mycobacterium tuberculosis culture in a fixed amount in lung tissues and count of Mycobacterium tuberculosis in alveolar macrophages were 2.6 +/- 0.5, (4.40 +/- 4.00) x 10(4) CFU and 7.2 +/- 3.2 respectively in pneumoconiosis complicated with tuberculosis and injecting Mycobacterium vaccae group, while 3.1 +/- 0.3, (18.9 +/- 18.2) x 10(4) CFU and 12.5 +/- 6.3 respectively in the control group. And statistically significant differences were found between the two groups (P < 0.05, 0.01, 0.05 respectively). The histopathological analysis revealed that proliferative and lymphoid nodules were predominant in the pneumoconiosis complicated with tuberculosis and injecting Mycobacterium vaccae group, while necrotic nodules in the control group. CONCLUSION: Mycobacterium vaccae might play a role in prevention of pneumoconiosis complicating with tuberculosis.

Animals↗
PubMed1997

[An experiment study of reversed pulmonary hypertension with inhaled nitric oxide on smoke inhalation injury].

We evaluated the effect and mechanisms of reversed pulmonary hypertension with inhaled nitric oxide (NO) on smoke inhalation injury in the dog model, 21 dogs were divided into 3 groups randomly. Following smoke inhalation, the control group (n = 8) inhaled O2 (FiO2, 0.45) and the treated group (n = 9) inhaled O2 and 0.0045% (45 ppm) NO. Hemodynamics was serially measured for 12 hours. In addition, 4 dogs without smoke inhalation were used to study the normal lung histomophologic findings. The data were analyzed by ANOVA. After inhalation of NO, the mean pulmonary artery pressure (mPAP), pulmonary minute vessels pressure (Pmv), and pulmonary vascular resistance (PVR) were decreased significantly (P < 0.05), while the mean aortic pressure (mAP) and total peripheral resistance (TRP) were not remarkably changed (P > 0.05). The levels of cyclic guanosine monophosphate (cGMP) were increased significantly (P < 0.01). Inhaled NO may reverse pulmonary hypertension with smoke inhalation injury in dogs. The mechanism of selective pulmonary circulation was increased cGMP level in smooth cells. Inhaled NO may be recommended for clinical application.

Administration, Inhalation↗
PubMed1997

[ICAM-1 mRNA expression in the bronchial tissue of asthmatic guinea pigs].

To determine the expression of ICAM-1 mRNA in the bronchial tissue of asthmatic guinea pigs. The guinea pigs were divided randomly in to asthma, asthma treated with dexamethasone (DEX), and control groups. ICAM-1 expression was analyzed by in situ hybridization and the cellular infiltrate was evaluated by HE staining. In situ hybridization demonstrated ICAM-1 mRNA was mainly expressed in the cytoplasm of epithelial cells and endothelial cells. Compared with the control and DEX groups, a significant increase of ICAM-1 mRNA expression was observed in the bronchial tissue (P < 0.02 and 0.05 respectively). In asthmatic guinea-pigs, the intensity of ICAM-1 mRNA expression in bronchial tissue was correlated with total leucocyte infiltrate (P < 0.05). ICAM-1 expression in bronchial tissue may be related with the leucocyte infiltration and glucocorticoid may inhibit the expression of cell adhesion molecules.

Animals↗
PubMed1997

[Effects of CD11/CD18 on adhesion between endothelial cell and PMN and its expression in early stage postburn].

This study was to investigate the expressions of CD11a/CD18 and CD11b/CD18 on burn patient's polymorphonuclear neutrophil (PMN) in early postburn stage and effects of CD11/CD18 mAb on PMN-EC adhesion and endothelial cell (EC) damage induced by PMN. Adhesive rate between PMN and EC, the filtration coefficient (kf) and monolayer volume flux (Jv) were determined after incubating burn patient's PMN with human umbilical vein endothelial cell (HUVEC) for 24 hours. CD11a/CD18 monoclonal antibodies (mAb) and CD11b/CD18 mAb were used to pretreat burn patient's PMNs in order to demonstrate the role of CD11/CD18 in PMN-EC adhesion and EC damage. Expressions of CD11a/CD18 and CD11b/CD18 were determined by flow cytometry 1, 3, 5, 7 d postburn. The results indicated that expressions of CD11a/CD18 and CD11b/CD18 on burn patient's PMNs increased quickly, reaching the peak on day 1 postburn and remained in high level till 7 days postburn. The values of Kf and Jv were increased markedly after burn patient's PMNs was incubated with HUVECs, which were cultured on micropore filter membrane. When burn patient's PMNs were pretreated with CD11a/CD18 mAb and CD11b/CD18 mAb, PMN-HUVEC adhesive rate was inhibited by 70%-80% and the values of Jv and kf were decreased significantly. It suggested that there were increased expressions of CD11a/CD18 and CD11b/CD18 on PMNs after burn injury. Burn patient's PMNs could damage EC and increased EC monolayer permeability (kf, Jv). CD11/CD18 mAb inhibited PMN-EC adhesion and attenuated EC damage induced by PMNs.

Adolescent↗
PubMed1997

[Preparation of McAb against lung cancer and its application in tumor radioimmunoimaging].

OBJECTIVE: In order to tracing the lung cancer, A monoclonal antibody was produced. METHOD: The McAb, named SM-1, was specifically reacted with lung cancer confirmed by the immunopathological studies, then the McAb was digested into fragments by ficin and bromelain proteases. RESULTS: Both of the enzymatic methods were very effective and the immuno-reactivity of fragments was retained well. In our localization experiments, the T/NT ratio revealed that radioiodinated McAb and fragments could be specifically uptaked by the tumour tissue and the T/NT ratio was higher in fragments group than intact IgG. After injection of 131I-IgG and fragments, the xenografts of human lung cancer bearing in nude mice were visualized distinctly during 36-48 hrs. Eighteen patients with lung cancer received Tc-99m labeled McAb intravenously, 13 cases showed radioactive accumulation in the foci of tumours. CONCLUSION: These preliminary results suggested that SM-1 and its fragments might be a potential agents for radioimmunoimaging diagnosis of lung cancer.

Animals↗
PubMed1997

[Experimental study on the treatment of smoke inhalation injury with lung lavage and exogenous pulmonary surfactant].

To investigate the prevention and treatment effects of lung lavage and exogenous pulmonary surfactant (PS) on endogenous surfactant system dysfunction and acute respiratory failure caused by severe smoke inhalation, Wistar rats were randomly divided into five groups: Group I, normal control; Group II, smoke inhalation; Group III, smoke + lavage + PS + mechanical ventilation (MV); Group IV, smoke + lavage + MV; Group V, smoke + MV. The lungs were lavaged with 30 ml/kg 0.9% NaCl containing 100 mg/kg PS or same volume of saline via tracheal catheter at 5 min after smoke inhalation, then the animals were placed on a ventilator for 4 h, and observed until 24 h postinjury. The arterial blood gas levels, lung water volume, static lung compliance (Cst), total protein and albumin contents in bronchoalveolar lavage fluid (BALF), surface tension properties of BALF, and fatality rate at 24 h were measured. Smoke inhalation caused a similar acute hypoxia and severe carbon monoxide poisoning immediately in all injuried groups. The animals in group II showed acute respiratory failure, serious high permeability pulmonary edema, and surfactant system dysfunction. The surface tension properties of BALF, Cst, and the oxygenation were significantly improved with lung lavage and exogenous PS treatment. The lung water volume, total protein and albumin contents in BALF were decreased dramatically in this group. The fatality rate at 24 h declined markedly only in group III. It was suggested that lung lavage and exogenous surfactant treatment trestores effectively endogenous surfactant function inhibited by smoke inhalation, improves lung function, prevents high permeability pulmonary edema and respiratory failure, and decreases the mortality in early stage after smoke inhalation injury.

Animals↗