Biomedical subjects

Z Lin

Publications and source records attributed to Z Lin.

At least 73 records · Page 4Linked to original sources

PubMed2001

Cardiovascular disease risk stratification and comparison in a California population.

This study was designed to identify the need for primary prevention of cardiovascular disease in an HMO population and to develop appropriate interventions for individuals in different risk groups, based on risk stratification and comparison. The analysis is based on a cross-sectional survey of the HMO members of a large employer group. Respondents (n=17,878) were stratified based on the Framingham model; 34% of respondents without cardiovascular disease were classified as moderate to high attributable risk for the disease, and 66% were classified as low attributable risk. Results of logistic regression analyses suggest that, compared with respondents with pre-existing cardiovascular disease, moderate- to high-risk respondents are more likely to smoke, have unhealthy diets, and be overweight, hypertensive, and hypercholesterolemic. More low-risk respondents had unhealthy diets than did those with pre-existing cardiovascular disease. There were no differences between these groups for physical activity and stress. Respondents had fewer modifiable risk factors and healthier lifestyles than did those who were at risk. These findings suggest that primary prevention should be enhanced, especially among those with significantly increased risk for the disease. Moreover, the approaches of this project-population-based risk assessment, stratification, and comparison-were instrumental in identifying the target population and designing appropriate interventions. (c) 2001 by CHF, Inc.

Journal Article↗

PubMed2001

Selection and characterization of varicella-zoster virus variants resistant to (R)-9-[4-hydroxy-2-(hydroxymethy)butyl]guanine.

(R)-9-[4-Hydroxy-2-(hydroxymethy)butyl]guanine (H2G) is a potent and selective inhibitor of herpesvirus replication. It is a nucleoside analog, and its triphosphate derivative (H2G-TP) is a competitive inhibitor of herpesvirus DNA polymerases. In this study, the antiviral activities of H2G and acyclovir (ACV) and the development of viral resistance to these agents were compared in varicella-zoster virus (VZV)-infected cells. In plaque reduction assays, the 50% effective concentration of H2G for VZV was 60- to 400-fold lower than that of ACV, depending on the virus strain and the cell line tested. The enhanced efficacy of H2G against VZV can be accounted for in part by the fact that the intaracellular H2G-TP level (>170 pmol/10(6) cells) is higher than the intracellular ACV-TP level (<1 pmol/10(6) cells). In addition, H2G-TP has extended half-lives of 3.9 and 8.6 h in VZV-infected MRC-5 and MeWo cells, respectively. To assess the emergence of H2G-resistant VZV in vitro, VZV was passaged in the presence of increasing concentrations of H2G. Earlier in the passage, when the concentration of H2G was relatively low, the predominant variant had the (A)76 deletion in the viral thymidine kinase (TK) gene. This mutant was identical to an ACV-resistant mutant generated in parallel experiments. However, higher concentrations of H2G appeared to favor a novel mutant, which had deletions of two consecutive nucleotides at positions 805 and 806 of the TK gene. All of these changes introduced frameshift mutations in the TK gene resulting in the expression of truncated polypeptides. H2G-resistant viruses were cross-resistant to ACV, and vice versa.

Acyclovir↗

PubMed2001

Hypoxia induces apoptosis via two independent pathways in Jurkat cells: differential regulation by glucose.

Glucose uptake and metabolism inhibit hypoxia-induced apoptosis in a variety of cell types, but the underlying molecular mechanisms remain poorly understood. In the present study, we explore hypoxia-mediated cell death pathways in Jurkat cells in the presence and absence of extracellular glucose. In the absence of extracellular glucose, hypoxia caused cytochrome c release, caspase 3 and poly(ADP-ribose)polymerase cleavage, and DNA fragmentation; this apoptotic response was blocked by the caspase 9 inhibitor z-LEHD-FMK. The presence of extracellular glucose during hypoxia prevented cytochrome c release and activation of caspase 9 but did not prevent apoptosis in Jurkat cells. In these conditions, overexpression of the caspase 8 inhibitor v-FLIP prevented hypoxia-mediated cell death. Thus hypoxia can stimulate two apoptotic pathways in Jurkat cells, one dependent on cytochrome c release from mitochondria that is prevented by glucose uptake and metabolism, and the other independent of cytochrome c release and resulting from activation of the death receptor pathway, which is accelerated by glucose uptake and metabolism.

Apoptosis↗

PubMed2001

Pre- and postsynaptic inhibition by nociceptin in guinea pig small intestinal myenteric plexus in vitro.

Actions of nociceptin on electrical and synaptic behavior of morphologically and neurochemically identified neurons in the guinea pig duodenal myenteric plexus were studied with conventional techniques. Nociceptin hyperpolarized the membrane potential in 104 of 121 AH-type and 28 of 51 S-type neurons with an EC(50) of 11.9 +/- 1.2 nM. Increased K(+) conductance accounted for the hyperpolarizing responses that were blocked by pertussis toxin and unaffected by naloxone. The selective opioid receptor-like (ORL)(1) receptor antagonist [Phe(1)-psi(CH(2)-NH)-Gly(2)]nociceptin(1--13)-NH(2) suppressed the nociceptin-evoked responses while behaving like a partial agonist. The nonselective ORL(1) antagonist naloxone benzoylhydrazone competitively suppressed nociceptin actions with a pA(2) value of 5.8. Nociceptin acted at presynaptic inhibitory receptors to suppress fast excitatory nicotinic postsynaptic potentials in 25 of 30 neurons (EC(50) = 22.5 +/- 4.4 nM) and slow synaptic excitation in 38 of 45 neurons (EC(50) = 15.1 +/- 1.6 nM). Presynaptic inhibitory action of nociceptin was unaffected by naloxone and was antagonized by [Phe(1)-psi(CH(2)-NH)-Gly(2)]nociceptin(1--13)-NH(2) or naloxone benzoylhydrazone. The results suggest that nociceptin acts both pre- and postsynaptically by activating an ORL(1) receptor that is distinct from typical naloxone-sensitive opioid receptors.

Animals↗

PubMed2001

Surfactant protein gene A, B, and D marker alleles in chronic obstructive pulmonary disease of a Mexican population.

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation. It is most likely the result of complex interactions of environmental and genetic factors. Because pulmonary surfactant components play important roles in normal lung function, innate host defence, and inflammation in the lung, this study investigated the hypothesis that the surfactant protein genes are involved in certain cases of COPD. Genotype analysis of surfactant protein (SP)-A, SP-B, SP-B-linked microsatellite, and SP-D marker alleles was performed in patients with COPD (n=97) and smoker (n=82) or nonsmoker (n=99) controls. Univariate and multiple logistic regression analyses were performed. The regression analysis results between COPD and smokers revealed several COPD susceptibility alleles (AA62_A, B1580_C, D2S388_5), based on an odds ratio (OR >2.5). The predictive ability of this model for developing COPD is good (c=0.926). Allele-allele (B1580_C and D2S388_5) and allele-environment (i.e. smoking) interactions were detected. When smoker controls were compared to nonsmoker controls, marker D2S388 5 appeared to be smoking-independent (p=0.874), whereas marker alleles AA62_A (p=0.045) and B1580_5 (p=0.007) were smoking-dependent. Males were at higher risk (OR=6.05, p=0.001), and smoking (>50 packs x yr(-1)) increased risk (OR=5.38, p=0.007). Males and alleles of loci flanking SP-B were associated with more severe cases (forced expiratory volume in one second/forced vital capacity < or = 40%). The present results indicate that the surfactant protein alleles may be useful in chronic obstructive pulmonary disease by either predicting the disease in a subgroup and/or by identifying disease subgroups that may be used for therapeutic intervention. These observations should now be confirmed in a larger study, designed according to strict epidemiological criteria.

Aged↗

PubMed2001

An exploratory analysis of the effect of pesticide exposure on the risk of spontaneous abortion in an Ontario farm population.

The toxicity of pesticides on human reproduction is largely unknown--particularly how mixtures of pesticide products might affect fetal toxicity. The Ontario Farm Family Health Study collected data by questionnaire on the identity and timing of pesticide use on the farm, lifestyle factors, and a complete reproductive history from the farm operator and eligible couples living on the farm. A total of 2,110 women provided information on 3,936 pregnancies, including 395 spontaneous abortions. To explore critical windows of exposure and target sites for toxicity, we examined exposures separately for preconception (3 months before and up to month of conception) and postconception (first trimester) windows and for early (< 12 weeks) and late (12-19 weeks) spontaneous abortions. We observed moderate increases in risk of early abortions for preconception exposures to phenoxy acetic acid herbicides [odds ratio (OR) = 1.5; 95% confidence interval (CI), 1.1-2.1], triazines (OR = 1.4; 95% CI, 1.0-2.0), and any herbicide (OR = 1.4; 95% CI, 1.1-1.9). For late abortions, preconception exposure to glyphosate (OR = 1.7; 95% CI, 1.0-2.9), thiocarbamates (OR = 1.8; 95% CI, 1.1-3.0), and the miscellaneous class of pesticides (OR = 1.5; 95% CI, 1.0-2.4) was associated with elevated risks. Postconception exposures were generally associated with late spontaneous abortions. Older maternal age (> 34 years of age) was the strongest risk factor for spontaneous abortions, and we observed several interactions between pesticides in the older age group using Classification and Regression Tree analysis. This study shows that timing of exposure and restricting analyses to more homogeneous endpoints are important in characterizing the reproductive toxicity of pesticides.

Abortion, Spontaneous↗

PubMed2001

Focal congenital alveolar proteinosis associated with abnormal surfactant protein B messenger RNA.

Two siblings presented with typical clinical features of congenital pulmonary alveolar proteinosis (PAP). Necropsy of one sibling revealed scattered foci of the diagnostic histologic changes in the lung tissue. In contrast to infantile and adult PAP, focal distribution is uncommon in congenital PAP. Defective expression of the granulocyte-macrophage colony-stimulating factor receptor was ruled out. The surfactant protein B (SP-B) content in the lung tissue of the autopsied patient was low, and a deletion in the SP-B messenger RNA was detected. We speculate that the PAP in our patients was related to the reduced quantity and/or to the altered quality of SP-B.

Chromosome Deletion↗

PubMed2001

Immunohistochemical analysis of CD44s and CD44v6 in endometriosis and adenomyosis : comparison with normal, hyperplastic, and malignant endometrium.

The expression patterns of CD44s and CD44v6 were immunohistochemically compared with those of normal, hyperplastic and malignant endometrium. In normal endometria (n=37), endometrioses (n=46) and adenomyoses (n=20), the surface and glandular epithelial cells were negative for CD44s and CD44v6 in a proliferative pattern and positive in a secretory pattern, whereas the stroma was only positive for CD44s in both proliferative and secretory patterns. The endometrial hyperplasia (4 simple and 9 complex) had the identical patterns with normal proliferative phase of endometrium. Only one case showing complex hyperplasia with atypia was focally positive for CD44s and CD44v6 in glandular epithelia. CD44s and CD44v6 were positive in all endometrial adenocarcinomas (13), except one CD44s-negative case. In summary, the expressions of CD44s and CD44v6 in endometriosis and adenomyosis recapitulated those of normal cyclic endometrium. The expression patterns in endometrial hyperplasia were similar to those in normal proliferative endometrium, whereas the endometrial adenocarcinoma showed abnormal expressions for CD44s and CD44v6. Thus it was considered that the ectopic endometrium in endometriosis and adenomyosis was not aberrant as in endometrial carcinoma on the aspects of immunohistochemical expressions of CD44s and CD44v6.

Adenocarcinoma↗

PubMed2001

[Using fluorescence PCR analysis for early diagnosis and carriers detection of Chinese Wilson's disease].

OBJECTIVE: To diagnose the pre-symptomatic cases of Chinese Wilson's disease(WD) and detect the potential carriers by using fluorescence PCR technique. METHODS: Screening the high frequency spot Arg778Leu of WD gene mutation in 66 Chinese WD patients, 55 healthy family members and 30 controls, and selecting 3 random samples (2 from WD patients, 1 from controls) for DNA sequencing to testify the accuracy of fluorescence PCR. RESULTS: Among 66 Chinese WD cases, 5 were found homozygous for mutation of Arg778Leu and 21 were compound heterozygous; the gene mutation rate was totally 39.4%. Out of 55 healthy family members, 12 were found heterozygous, and it was confirmed that 11 of these 12 individuals were WD gene carriers but not pre-symptomatic patients. The results of direct DNA sequencing consisted with those results detected by fluorescence PCR. CONCLUSION: The Arg778Leu mutation in exon 8 is the high frequency spot of Chinese Wilson's disease gene. Fluorescence PCR analysis is a rapid, accurate gene diagnostic method and demonstrates a high detecting rate.

Adolescent↗

PubMed2001

[Relationship between differential expression patterns of multigene families and heterosis in a wheat diallel crosses].

In order to understand molecular basis of heterosis, the patterns of differential gene expression of multigene families between wheat hybrids and their parents in seedling leaves were analyzed by using mRNA differential display. Relationships between differential gene expression patterns, heterosis and F1 hybrid performance were determined. Four patterns of differential gene expression were observed, which include: (1) bands observed in both parents but not in the F1; (2) bands occurring in only one parent but not in the F1 or the other parent; (3) bands detected in only the F1 but neither of the parents; (4) bands present in one parent and F1 but absent in the other parent. The analysis showed that patterns of differential gene expression were not correlated with the F1 hybrid performance for all the eight agronomic traits. However, differentially expressed fragments that occurred only in the F1 but neither of the parents were found to be positively correlated with heterosis. On the contrary, fragments observed in both parents but not in the F1 were negatively correlated with heterosis. It is concluded that the differential expression of regulatory genes plays an important role in heterosis.

Crosses, Genetic↗

PubMed2001

[Modification of the Photobacterium phosphoreum toxicity test method].

In order to reduce the variation of Photobacterium phosphoreum luminous intensity during testing, the Photobacterium phosphoreum toxicity test was modified by a correction factor, PIacetone, in this paper. The effects of magnetic stirring time, culture time, culture generation and culture temperature on the measured results were discussed. The modified method had good laboratory repeatability and the relative standard deviation (RSD) was between 2.1% and 13.1%. Reliable data could be obtained using the modified method. It would be beneficial to the development of the quantitative structure-activity relationships on multicomponent organic compounds.

Luminescent Measurements↗

PubMed2001

Identification of SNPs in human gamma aminobutyric acid A receptor gamma2 gene.

Gamma aminobutyric acid (GABA) is a major inhibitory neurotransmitter. Because of its importance and diverse functions, studies of single nucleotide polymorphisms in the GABA receptor genes are of great significance, which may produce useful molecular markers for genetic analysis of neurological disease, and possibly lead to the discovery of pathogenic mutations. We identified eleven SNPs in the entire exon regions, immediate intron regions and promoter region of human GABA receptor gamma2 gene by direct sequencing. In this discovery, 2 non-synonymous cSNPs and 1 splicing variant are found.

Evolution, Molecular↗

PubMed2001

[Total auricle reconstruction with postauricular flap and a Medpor framework].

OBJECTIVE: To introduce a new method and technique of auricle reconstruction. METHOD: The postauricular flap was designed to cover a Medpor framework for auricle reconstruction. The vascular pedicle of the flap was at the temporal part. The operation was performed on 12 patients, of whom 8 patients were with microsomia; 4 patients had total auricle defects. RESULTS: Postoperative follow-up period was 8 months in average. All the 12 patients obtained satisfactory appearance of the reconstructed ears. CONCLUSION: Clinical applications showed several advantages of this method.

Adolescent↗

PubMed2001

[Immunological mechanism of human alpha-interferon gene therapy for treatment of melonoma].

OBJECTIVE: To investigate the possibility of alpha-INF gene therapy for treatment of melonoma. METHODS: An experimental model of fibroblast-mediated human alpha-IFN gene therapy was established for treatment of melonoma and the activity of NK and M phi was determined. RESULTS: The NK and M phi activity was increasing significantly after the implantation of alpha-IFN secreted by cloning the fibroblast in vivo. Good therapeutic results could be achived if the NIH3T3-IFN-alpha+ cells were combined with the IL-2/AK. CONCLUSION: The results has indicated that the fibroblast-mediated gene therapy could be good to use it for the treatment of human melonoma. More effective results could be achieved by using it in combination with IL-2.

3T3 Cells↗

PubMed2001

[Comparison between one-site and two-site incision in phacotrabeculectomy].

OBJECTIVE: To compare the effect of one-site and two-site incision in phacotrabeculectomy in terms of intraocular pressure control. METHODS: Forty-five cases (47 eyes) of phacotrabeculectomy were retrospectively reviewed. The nuclei of all the cases were not harder than Grade III. One-site approach was performed on 29 eyes, and two-site approach, on 18 eyes. The effects of intraocular pressure control were compared between the two groups. RESULTS: Follow-up was 13-30 months (mean 18.9 months). The postoperative intraocular pressure in the one-site group was (16.81 +/- 4.56) mm Hg (1 mm Hg = 0.133 kPa), (15.32 +/- 6.67) mm Hg lower than that before surgery. And the postoperative intraocular pressure in the two-site group was (17.63 +/- 4.60) mm Hg, (16.42 +/- 6.98) mm Hg lower than that before surgery. There was no significant difference between the two groups relative to the effect of intraocular pressure control (t = 1.44, P > 0.05). CONCLUSION: Phacotrabeculectomy, either with one-site approach or with two-site approach, can provide good intraocular pressure control. The effects are similar between the two approaches in soft cataract patients.

Adult↗

PubMed2001

[Transcatheter arterial chemoembolization for postoperative residual tumor of hepatocellular carcinoma].

OBJECTIVE: To understand and analyze the survival and prognostic factors of postoperative residual tumor of hepatocellular carcinoma treated by transcatheter arterial chemoembolization. METHODS: Transcatheter arterial chemoembolization was performed in 74 patients who were identified as having residual lesions by ultrasonography, hepatic arterial angiography or enhanced computed tomography about two months after resection of hepatocellular carcinoma. Kaplan-Meier method was used for survival and Cox regression model for prognostic factors. RESULTS: The 1-, 2- and 3-year survival rates were 78.0%, 57.6%, 37.0%, with a median survival of 33 months. Univariate analysis indicated that a primary tumor over > 5 cm in diameter, vascular involvement by the primary tumor and TNM extent of the residual lesion were important factors indicating a bad prognosis, where as the combination of other treatment methods such as percutaneous ethanol injection (PEI), and/or radiotherapy indicated a better prognosis. However, multivariate analysis showed that vascular involvement by the primary tumor and the other combined local treatments were independent factors of prognosis. CONCLUSION: Transcatheter arterial chemoembolization is effective in treating the postoperative residual tumor of hepatocellular carcinoma. Further improvement is observed if combined with other local therapies such as percutaneous ethanol injection or radiotherapy.

Adolescent↗

PubMed2001

Self-designed conical point contact plate and clinical application.

OBJECTIVE: To design a new kind of conical point contact plate (CPCP) in treatment of diaphyseal fracture to avoid further dam age to the blood supply of the cortex. METHODS: There were 4 pairs of conicles with a diameter of 1. 5-4 mm beneath the plate symmetrically. The nibs of the conicles were embedded about 1-1.5 mm in the cortex by the axial force of screws. The conicle provided a gap about 2 mm between the plate and the bone so as not to compress the periosteum and cortex. And the periostem did not need to be stripped off during operation and there was no need of postoperative external fixation. RESULTS: Forty-two cases with diaphyseal fracture were stabilized by using CPCP. The patients could do joint exercise without loading after operation. Partial weight bearing could be performed in 4-6 weeks postoperatively. There was no obvious external callus in these cases. The average time of bone healing was 3 months in the tibia and forearm fracture and 4 months in the femur. Complications such as infection, non-union or malunion etc. were not found. The implant was removed 6-10 months after operation. CONCLUSIONS: CPCP has the advantages of drastic reduction of the implant-to-bone interface virtually, elimination of the impairment of the periosteal blood supply, increase of the rate of healing and good stability which meets the need of early functional exercise.

Adolescent↗

PubMed2001

[Phalloplasty using an abdominal flap with two sources of blood supply (16 cases reports)].

OBJECTIVE: To improve the survival of a reconstructed penis and reduce injury of the donor site at the abdominal wall. METHODS: Sixteen cases of phalloplasty were performed using an abdominal flap based on two sources of blood supply i.e. the cutaneous branches of the inferior epigastric blood vessel and the superficial epigastric blood vessel. RESULTS: All of the operations were successful. CONCLUSIONS: With abundant blood supply and high survival rate and the advantage of easy transposition, the flap is a good option for phalloplasty.

Abdomen↗