Biomedical subjects

T Zhao

Publications and source records attributed to T Zhao.

At least 55 records · Page 3Linked to original sources

PubMed2000

Nucleotide sequence analyses of partial envgp46 gene of human T-lymphotropic virus type I from inhabitants of Fujian Province in Southeast China.

Partial sequences from the env(gp46) gene of two human T-lymphotropic virus type I (HTLV-I) isolates (LIN and WEN) obtained from inhabitants of Fujian Province in southeast China were analyzed. A phylogenetic tree was constructed from these sequence data and those of other known HTLV-I isolates from all over the world. Comparisons of the LIN and WEN nucleotide sequences with other HTLV-I isolates showed diversity ranging from 0.73 to 7.00% for LIN and from 0.87 to 7.00% for WEN. Sequences of isolates LIN, WEN, MT-2, TSP1, and CH were most closely related, and the phylogenetic tree showed that all belong to the widespread subtype A of the cosmopolitan group. These preliminary data indicate that HTLV-I isolates from Fujian Province, China are closely related to HTLV-I strains from Japan and the Caribbean.

Base Sequence↗

PubMed2000

Genetic polymorphism of RhD-negative associated haplotypes in the Chinese.

The Rh blood group is the most polymorphic human blood group system, and is clinically significant in transfusion medicine. Individuals are classified as Rh-positive and Rh-negative depending on the presence or absence of the D antigen on the red cell surface. The RhD-negative trait could be generated by multiple genetic mechanisms, which have been shown to be ethnic group-dependent. In this study, we evaluated the status of seven RHD-specific exons (exons 3, 4, 5, 6, 7, 9, and 10) and RH intron 4 in 119 Chinese blood donors, using the sequence-specific primers polymerase chain reaction (SSP-PCR). Of the 87 individuals who were RhD-negative, 52 with the ce/ce, ce/cE, or Ce/ce genotype (60%) lacked the above seven RHD exons; 22 with the Ce/Ce or Ce/ce genotype (25%) had all the RHD exons examined; 13 with the Ce/ce genotype (15%) carried at least one RHD exon. Antigen association analysis suggested the existence of a novel class of RhD-negative associated haplotypes in the Chinese, tentatively denoted D(nf)Ce. The D(nf)Ce haplotype consisted of a normal RHCe allele and a nonfunctional RHD gene, which vary depending on the structure of the RHD gene. Among the RhD-negative Chinese, the estimated frequencies of the dce, dCe, and D(nf)Ce haplotypes were 0.7500, 0.0465, and 0.2035, respectively. No statistically significant deviation from Hardy-Weinberg equilibrium was observed using this genetic model.

China↗

PubMed2000

Production of monoclonal antibody to deltorphin-I and its immunocytochemical application to adult rat brain and cultured rat brain neurons.

A monoclonal anti-deltorphin-I antibody specifically recognizing its NH2-terminal region was produced. In the adult rat brain sections, it recognized immunoreactive nerve fibers mainly in the bed nucleus of stria terminalis, central nucleus of amygdala, lateral hypothalamus, hippocampus, substantia nigra, periaqueductal gray and locus ceruleus. Occasionally, positive somata were localized in the bed nucleus of stria terminalis, central nucleus of amygdala, supraoptic and periventricular nuclei. In primarily cultured neurons from various brain regions of new-born rats, the antibody immunostained strongly neuronal somata and processes. The abundant DADTI-immunoreactive substance in the cultured neurons promises to provide an alternative pathway to search for the counterpart of deltorphins in mammals.

Amygdala↗

PubMed2000

Genetic aberration in primary hepatocellular carcinoma: correlation between p53 gene mutation and loss-of-heterozygosity on chromosome 16q21-q23 and 9p21-p23.

To elucidate the molecular pathology underlying the development of hepatocellular carcinoma (HCC), we used 41 highly polymorphic microsatellite markers to examine 55 HCC and corresponding non-tumor liver tissues on chromosome 9, 16 and 17. Loss-of-heterozygosity (LOH) is observed with high frequency on chromosomal region 17p13 (36/55, 65%), 9p21-p23 (28/55, 51%), 16q21-q23 (27/55, 49%) in tumors. Meanwhile, microsatellite instability is rarely found in these microsatellite loci. Direct sequencing was performed to detect the tentative mutation of tumor suppressor genes in these regions: p53, MTS1/p16, and CDH1/E-cadherin. Within exon 5-9 of p53 gene, 14 out of 55 HCC specimens (24%) have somatic mutations, and nucleotide deletion of this gene is reported in HCC for the first time. Mutation in MTS1/p16 is found only in one tumor case. We do not find mutations in CDH1/E-cadherin. Furthermore, a statistically significant correlation is present between p53 gene mutation and loss of chromosome region 16q21-q23 and 9p21-p23, which indicates that synergism between p53 inactivation and deletion of 16q21-q23 and 9p21-p23 may play a role in the pathogenesis of HCC.

Cadherins↗

PubMed2000

Prevalence of childhood asthma, allergic rhinitis and eczema in Urumqi and Beijing.

OBJECTIVE: To assess the prevalence of asthma and other allergies in children in Urumqi and Beijing, compared with that in Hong Kong. METHODS: A total of 7754 primary school students were randomly selected to participate in the study. Data were collected in 1995-96 using the International Study of Asthma and Allergies in Childhood (ISAAC) protocol for 6- and 7-year-olds. The study design and data quality assurance in all aspects followed the protocol, including the double entry of data. RESULTS: The questionnaire response rate was high (98.9%). Beijing children reported significantly more asthma than those living in Urumqi in three categories: wheezing or whistling in the chest in the past year (6.0%, 95% confidence interval (CI): 5.1-6.9% vs 2.9%, 2.3-3.5%, P < 0.001), sleeping disturbed due to wheezing (1.3%, 0.9-1.7% vs 0.6%, 0.3-0.9%, P < 0. 03) and having experienced asthma ever (10.7%, 9.6-11.8% vs 7.6%, 6. 6-8.6%, P < 0.001). The prevalence of allergic rhinitis (30.0% vs 31. 1% estimated as 12-month nasal symptoms in Beijing and Urumqi, respectively) and eczema (2.8% vs 2.0% recorded as 12-month itchy rash) in the two cities were not significantly different. A similar study was also performed in Hong Kong in 1995 using the same ISAAC protocol. The children in Urumqi and Beijing had fewer (P < 0.05) allergic symptoms compared to those living in Hong Kong (n = 3618). The 12-month prevalence of wheezing, nasal symptoms and itchy rash found in Hong Kong were 9.2% (95% CI: 8.2-10.2%), 35.1% (33.5-36.7%) and 4.2% (3.5-4.9%), respectively. CONCLUSION: : Urumqi, Beijing and Hong Kong represent communities at different stages of westernization and the results from these three cities reflect a worldwide trend for an increasing prevalence of allergies along with westernization. These three cities could assist in identifying risk factors involved in the increase in asthma, allergic rhinitis and eczema.

Asthma↗

PubMed2000

Fate of Campylobacter jejuni in butter.

An outbreak of Campylobacter enteritis was associated with a restaurant in Louisiana during the summer of 1995. Thirty cases were identified, and four required hospitalization. Campylobacter jejuni was isolated from the patients, and epidemiologic studies revealed illness associated with eating garlic butter served at the restaurant. Three batches of garlic butter prepared by the restaurant associated with the outbreak and a C. jejuni isolate obtained from a patient involved in the outbreak were used for studies to determine the fate of C. jejuni in garlic butter. Studies also were done to determine the efficacy of the heat treatment used by the restaurant to prepare garlic bread to kill C. jejuni. Garlic butter was inoculated with approximately 10(4) and 10(6) CFU/g of C. jejuni and held at 5 or 21 degrees C. Results revealed that the survival of C. jejuni differed greatly, depending on the presence or absence of garlic. At 5 degrees C, C. jejuni populations decreased to an undetectable level (<10 CFU/g) within 3 h for two batches and within 24 h for another batch. In contrast, C. jejuni could survive at 5 degrees C for 13 days in butter with no garlic. At 21 degrees C, C. jejuni populations decreased to an undetectable level within 5 h for two batches and to 50 CFU/g in 5 h for another batch. In contrast, C. jejuni was detected at 500 CFU/g at 28 h after inoculation but was undetectable at 3 days in butter with no garlic held at 21 degrees C. The heating procedure (135 degrees C, 4 min) used to make garlic bread by the implicated restaurant was determined not to be sufficient for killing C. jejuni, with the internal temperature of the buttered bread after heating ranging from 19 to 22 degrees C. This study revealed that C. jejuni can survive for many days in refrigerated butter, but large populations (10(3) to 10(5) CFU/g) are killed within a few hours in butter that contains garlic. Furthermore, the heat treatment used by the restaurant to melt garlic butter in making garlic bread was not adequate to kill C. jejuni.

Animals↗

PubMed2000

Effects of diet on rumen proliferation and fecal shedding of Escherichia coil O157:H7 in calves.

Calves inoculated with Escherichia coli O157:H7 and fed either a high-roughage or high-concentrate diet were evaluated for rumen proliferation and fecal shedding of E. coli O157:H7. Calves fed the high-roughage diet had lower mean rumen volatile fatty acid concentrations and higher rumen pH values than did calves fed the high-concentrate diet. Despite these differences in rumen conditions, the calves fed the high-roughage diet did not have greater rumen populations of E. coli O157: H7 and did not exhibit increased or longer fecal shedding compared with the calves fed the high-concentrate diet. Two calves shedding the highest mean concentrations of E. coli O157:H7 were both fed the high-concentrate diet. There was a significant (P < 0.05) positive correlation between fecal shedding and rumen volatile fatty acid concentration in calves fed a high-concentrate diet. The effects of diet on E. coli O157:H7 proliferation and acid resistance were investigated using an in vitro rumen fermentation system. Rumen fluid collected from steers fed a high-roughage diet, but not from steers fed a high-concentrate diet, supported the proliferation of E. coli O157:H7. Rumen fluid from steers fed a high-concentrate diet rapidly induced acid resistance in E. coli O157:H7. The impact of diet on fecal shedding of E. coli O157:H7 is still unclear and may depend on dietary effects on fermentation in the colon and on diet-induced changes in the resident microflora. However, rapid development of acid tolerance by E. coli O157:H7 in the rumens of calves fed high-concentrate diets, allowing larger populations to survive passage through the acidic abomasum to proliferate in the colon, may be one factor that influences fecal shedding in cattle on feed.

Animal Feed↗

PubMed2000

[Study of ADRV antibody persistence in the serum of ADRV positive cases].

OBJECTIVE: This research aimed at observing the persistent time of ADRV antibody in the sera of ADRV cases. METHODS: We adopted a sensitive and specific Enzyme-linked immunosorbent assay (ELISA) for detecting ADRV antibody in patients who had recovered. RESULTS: We tested 260 human sera from Yi-Ma town of Henan Province. One year, six years and ten years after the patients had recovered, the of positive rates for ADRV antibody were respectively 27.7%, 36.3% and 23.3%. Thirty subjects of ADRV antibody positive were followed up retrospectively, no recurrent diarrhea was found. CONCLUSIONS: The ADRV antibody can last 16 years after primary infection.

Adult↗

PubMed2000

[Total nose reconstruction with a reversed mandibular flap pedicled with the facial artery].

OBJECTIVE: To investigate the method to repair different kinds of nasal defects. METHODS: The reversed mandibular flap pedicled with the facial artery was used. RESULTS: The treatment was completed in one stage and the results were satisfactory in 6 cases. The reconstructed noses showed good shape. CONCLUSIONS: Total nose reconstruction using a reversed mandibular flap is a new operation design and technique. The recipient and the donor sites are very close. The flap with excellent blood supply has a good colour and textural match. The operative procedure and flap transferring are easy.

Adolescent↗

PubMed2000

[Comparison of susceptibility testing results of M. tuberculosis by different methods].

OBJECTIVE: To compare the susceptibility testing results of M. tuberculosis detected with different standards and methods. METHOD: 158 strains of M. tuberculosis isolated from clinical patients were detected for the drug sensitivity by Chinese standard and method (absolute concentration method), 1% resistance ratio and absolute concentration method of WHO/IUATLD standard. RESULTS: The drug-resistant rate detected by the standard of WHO/IUATLD was 53.8%(85/158), while by the Chinese standard 50.0%(79/158). The drug-resistant rates to INH, SM, EMB and RFP by WHO/IUATLD standard were 41.8%(66/158), 34.2%(54/158), 22.1%(35/158) and 27.8%(44/158) respectively, whereas by the Chinese standard 34.2%(54/158), 30.4% (48/158), 18.4%(29/158) and 27.2%(43/158) respectively. There was no significant difference between the results detected with WHO/IUATLD and Chinese standard, except for the results of INH. There was no significant difference between the results detected with WHO/IUATLD standard by 1% resistant ratio and absolute concentration methods. CONCLUSION: The results of drug-sensitivity were interfered by the detected standards but not by the tested methods.

Antitubercular Agents↗

PubMed2000

[Preventive effects of three kinds of inactive vaccines against epidemic hemorrhagic fever (EHF) after 5 years of vaccination].

OBJECTIVE: To observe the safety and the preventive effects of three kinds of vaccines as Mongolian gerbils kidney vaccine, mouse brains vaccine and hamster kidney vaccine inoculated 5 years ago. METHODS: Field study and laboratory tests were carried out by random grouping and IFAT, MCPENT, ELISA, HI tests. RESULTS: The antibody-dependent enhancement did not appear in all individuals who received vaccines after four or five years. The seroconversion rates of MCPENT were 8.97%, 11.76% and 18.75% while the seroconversion rates of IFAT were 20.73%, 30.22% and 23.40% respectively for Mongolian gerbils kidney vaccine, mouse brains vaccine and hamster kidney vaccine. The protection rates were 100% for all three kinds of inactive vaccines which showed good epidemiological efficacy. CONCLUSION: The vaccines can protect clinical infection of EHF effectively after four or five years of the initial vaccination.

Animals↗

PubMed2000

[Relationship between the changes of serum free fatty acids and insulin resistance in type 2 diabetics].

The purpose of this study was to investigate the changes of serum free fatty acids (FFA) in fasting state and absorptive state and the relationship between FFA changes and insulin resistance in the patients with type 2 diabetes (DM2). 75 g of glucose were given to 60 patients with DM2. Fasting serum FFA, serum insulin levels and the same parameters 2 h after glucose load were measured by calorimetric and RIA methods. Fasting and 2 h after oral glucose tolerance test (OGTT) plasma glucose(PG) levels were also assessed by using glucose oxidase method. The results showed the levels of serum FFA, PG and insulin of fasting and after glucose load in the patients were significantly increased and their insulin-sensitive (ISI) was remarkably decreased as compared with those in 30 normal controls, P < 0.05. Multiple stepwise regression analysis showed that the FFA level of 2 h after OGTT was negatively correlated with ISI, P = 0.0304. The results suggest that in patients with DM2, the levels of fasting and absorptive FFA are significantly elevated, which is negatively correlated with the decline of ISI, implying the association of abnormal fasting and absorptive FFA and insulin resistance in patients with type 2 diabetes.

Adult↗

PubMed2000

[Methionine synthase and neural tube defects].

It has been indicated lately that higher plasma homocysteine is one of the risk factors in neural tube defects(NTDs) and vascular disease. Methionine synthase is a key enzyme in homocysteine metabolism. The defects of methionine synthase activity could result in hyperhomocysteinemia and methionine auxotrophy. The gene mutations of methionine synthase with the epidemiological studies of NTDs are reviewed in this paper. It is considered that the gene mutations of methionine synthase can not make a relation to NTDs and hyperhomocysteine, but methionine synthase reductase may be a clue for the study on NTDs in the future.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗

PubMed2000

[The study on the role of telomerase activity in human nasopharyngeal carcinoma].

OBJECTIVE: To elucidate the role of telomerase activity in nasopharyngeal carcinoma (NPC). METHODS: Telomerase activity was detected using the telomere repeat amplification protocol(TRAP) combined with silver staining in 42 low-differentiated squamous carcinoma, 10 normal nasopharyngeal mucosae and 8 nasopharyngeal fibrohemangioma. RESULTS: Telomerase activity was detectable in 20% normal nasopharyngeal mucosae and 88.1% in NPC. The activity of telomerase was not detectable in 8 nasopharyngeal fibrohemangioma tissues. Telomerase activity was present more frequently in NPC biopsies with positive lymph node metastasis than in those without lymph node metastasis (P = 0.035). Furthermore, telomerase activity was observed more frequently in advanced NPC than in early stage (P = 0.048). However, there was no evidence to show the relationship between telomerase activity and other clinical features, such as age, gender and distant metastasis (P > 0.05). Serum EBV marker(VCA-IgA) was observed more frequently in NPC than in normal nasopharyngeal mucosae patients(P < 0.001). CONCLUSION: Telomerase activity may play a critical role in the tumorigenesis of NPC. Detection of telomerase activity combined with serological EBV markers may contribute to the screening and early diagnosis of NPC.

Adolescent↗

PubMed2000

[Photoluminescence study of star-like C60(CH3)x(PAN)x copolymer].

Thin film of new synthesized C60(CH3)x(PAN)x copolymer was fabricated by physical jet deposition (PJD) technique. C60 molecule lies in the center of the star-like copolymers. PAN main chain is modified around the C60 molecules. Absorption and photoluminescence spectra show that there are strong interaction between C60 molecule and PAN, which depends on the length of PAN chain. Partly excitation transfer process between C60 molecule and PAN was observed, which leads to the fluorescence quenching of the PAN.

English Abstract↗

PubMed1999

The role of human glutathione S-transferases hGSTA1-1 and hGSTA2-2 in protection against oxidative stress.

In order to elucidate the protective role of glutathione S-transferases (GSTs) against oxidative stress, we have investigated the kinetic properties of the human alpha-class GSTs, hGSTA1-1 and hGSTA2-2, toward physiologically relevant hydroperoxides and have studied the role of these enzymes in glutathione (GSH)-dependent reduction of these hydroperoxides in human liver. We have cloned hGSTA1-1 and hGSTA2-2 from a human lung cDNA library and expressed both in Escherichia coli. Both isozymes had remarkably high peroxidase activity toward fatty acid hydroperoxides, phospholipid hydroperoxides, and cumene hydroperoxide. In general, the activity of hGSTA2-2 was higher than that of hGSTA1-1 toward these substrates. For example, the catalytic efficiency (kcat/Km) of hGSTA1-1 for phosphatidylcholine (PC) hydroperoxide and phosphatidylethanolamine (PE) hydroperoxide was found to be 181.3 and 199.6 s-1 mM-1, respectively, while the catalytic efficiency of hGSTA2-2 for PC-hydroperoxide and PE-hydroperoxide was 317.5 and 353 s-1 mM-1, respectively. Immunotitration studies with human liver extracts showed that the antibodies against human alpha-class GSTs immunoprecipitated about 55 and 75% of glutathione peroxidase (GPx) activity of human liver toward PC-hydroperoxide and cumene hydroperoxide, respectively. GPx activity was not immunoprecipitated by the same antibodies from human erythrocyte hemolysates. These results show that the alpha-class GSTs contribute a major portion of GPx activity toward lipid hydroperoxides in human liver. Our results also suggest that GSTs may be involved in the reduction of 5-hydroperoxyeicosatetraenoic acid, an important intermediate in the 5-lipoxygenase pathway.

Dose-Response Relationship, Immunologic↗

PubMed1999

Role of glutathione S-transferase 8-8 in allylamine resistance of vascular smooth muscle cells in vitro.

Allylamine (AA) is a cardiovascular toxin that causes lesions resembling atherosclerosis in several mammalian species. AA's toxic effects are thought to be exerted through its conversion to acrolein (AC), a potent electrophilic alkylating agent and atherogen. Semicarbazide sensitive amine oxidase (SSAO) catalyzes the oxidation of AA to AC. Glutathione S-transferases (GST) can catalyze the first step of detoxification of AC to mercapturic acid. Our previous studies suggest that the isozyme rGST8-8 is a principal defense against electrophilic stress exerted by alpha,beta-unsaturated carbonyls such as AC. In the present studies, we use cultured rat vascular smooth muscle cells (VSMC) to examine the relative roles of SSAO and rGST8-8 in the cytotoxic effects of the atherogens, AA and AC. Exposure derived AA-resistant cells (VSMC-AA) were 3.5-fold more resistant to AA when compared to VSMC and 1.8-fold more resistant to acrolein. SSAO activity was 2-fold higher in VSMC-AA than in VSMC. Consistent with the role of SSAO in biotransformation of AA, the SSAO inhibitor semicarbazide (SC; 100 microM) provided nearly complete protection from AA to both VSMC-AA and VSMC. As expected, SC did not affect the cytotoxicity of AC. Pretreatment with 100 microM sulfasalazine (SS), a GST inhibitor, potentiated AA and AC toxicity in both VSMC-AA and VSMC, indicating a protective role of GST. Catalytic efficiency (K(cat)/K(m)) of GSTs was higher toward 4-hydroxynonenal (4-HNE) (0.65 mM(-1) s(-1)) than toward 1-chloro-2, 4-dinitrobenzene (CDNB) (0.14 mM(-1) s(-1)) for VSMC. In VSMC-AA, K(cat)/K(m) was increased 4.1-fold toward CDNB (0.58 mM(-1) s(-1)) and 6-fold toward 4HNE (3.9 mM(-1) s(-1)) when compared to VSMC, indicating a preferential increase in VSMC-AA of GST isozymes which utilize alpha,beta-unsaturated carbonyls. Western blots confirmed induction of rGST8-8 in VSMC-AA. Expression of recombinant mGSTA4 (the mouse homolog of rGST8-8) in VSMC caused a 1.6-fold increase in resistance to AA and AC. This resistance was fully reversed by 50 microM SS. Our results demonstrate that GSTs are an important defense against electrophilic atherogens and that isozymes with high activity toward alpha,beta-unsaturated carbonyls are particularly important in the vascular wall.

Acrolein↗

PubMed1999

Phosphorylation of heterochromatin protein 1 by casein kinase II is required for efficient heterochromatin binding in Drosophila.

Heterochromatin-associated protein 1 (HP1) is a nonhistone chromosomal protein with a dose-dependent effect on heterochromatin mediated position-effect silencing. It is multiply phosphorylated in vivo. Hyperphosphorylation of HP1 is correlated with heterochromatin assembly. We report here that HP1 is phosphorylated by casein kinase II in vivo at three serine residues located at the N and C termini of the protein. Alanine substitution mutations in the casein kinase II target phosphorylation sites dramatically reduce the heterochromatin binding activity of HP1, whereas glutamate substitution mutations, which mimic the charge contributions of phosphorylated serine, have apparently wild-type binding activity. We propose that phosphorylation of HP1 promotes protein-protein interaction between HP1 and target binding proteins in heterochromatin.

Animals↗