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Biomedical subjects

Q Wei

Publications and source records attributed to Q Wei.

At least 163 records · Page 9Linked to original sources
PubMed1995

Taxonomic status of car bacillus based on the small subunit ribosomal RNA sequences.

In an attempt to identify the taxonomic relationship between CAR bacillus and other bacteria, the SSU rRNA gene sequences of two CAR bacillus strains, CBM and CBR isolated from mice and rats respectively were used in the present studies. The SSU rRNA gene sequences, approximately 1.5 kb in size amplified from genomic DNAs from both strains, were determined and 96.8% homologies were found to exist between them. Those sequences were aligned to most eubacteria with a computer search showing high homology with those of Flavobacter/Flexibacter species especially closed to Fx. sancti and Fv. ferrugineum. Phylogenetic analysis indicated that CAR bacillus belongs to a species close to Fx. sancti and Fv. ferrugineum subdivision.

Animals↗
PubMed1994

DNA repair and susceptibility to basal cell carcinoma: a case-control study.

This study investigated the role of DNA repair in susceptibility to sunlight-induced basal cell carcinoma using a host cell reactivation assay in peripheral lymphocytes. The study included Maryland basal cell carcinoma patients and cancer-free dermatologic controls who had had noncancerous skin disorders diagnosed between 1987 and 1990. Logistic regression models were used to assess the independent effect of the selected variables stratified by DNA repair level, with adjustment for age and family history. Skin type, lifetime number of severe sunburns, and actinic elastosis were also selected as risk factors for basal cell carcinoma. Cryopreserved lymphocytes from 88 cases and 135 controls were used for the DNA repair assay. When data were stratified by DNA repair level and adjusted for age and family history of skin cancer, significantly increased odds ratios associated with lighter skin (odds ratio (OR) = 3.2, 95% confidence interval (CI) 1.5-7.3), six or more severe sunburns in a lifetime (OR = 4.2, 95% CI 1.6-10.7), and moderate or severe actinic elastosis (OR = 4.4, 95% CI 1.5-12.8) were observed in persons with low DNA repair but not in those with high DNA repair. These findings suggest that impaired DNA repair may be a susceptibility factor for sunlight-induced skin cancer in the general public, as it is in patients with xeroderma pigmentosum.

Adult↗
PubMed1994

DNA repair related to multiple skin cancers and drug use.

Defective repair of sunlight-induced DNA photodamage, coupled with an unusually high occurrence of multiple primary basal cell carcinomas (BCCs), is the major characteristic of xeroderma pigmentosum. Our recent work has indicated that this etiological paradigm may apply to skin cancer patients without an apparent hereditary disease. The present study reports on an investigation of whether medications such as photosensitizing drugs (antibiotics, corticosteroids, and aspirin) modulate skin cancer risk through alterations in DNA repair capacity (DRC). Using a new DNA repair (host cell reactivation) assay with peripheral T-lymphocytes, we tested DRCs of 88 Caucasian BCC patients and 135 cancer-free controls. Subjects were between 20 and 60 years of age and free of known hereditary skin diseases. The age-adjusted means of DRC were calculated to compare repair levels associated with the use of specific drugs and hormones. Multiple linear regression models were used to correlate DRC with the number of skin cancers. The estimated odds ratio was used to describe the risk of BCCs. The distribution of DRCs of subjects was approximately normal, with a 5-fold variation between individuals. DRCs below the upper 30th percentile of controls were associated with an estimated 2.3-fold (95% confidence interval, 1.17-4.54-fold) increased risk for the occurrence of BCCs. The lower the DRC was, the greater the number of skin tumors in individuals (P < 0.05), after adjustment for age. Although supplemental vitamin use was associated with reduced risk of skin cancer, it was not associated with differences in subjects' DRCs. However, individuals who reported taking either tetracycline or estrogen, two photosensitizing drugs, had higher DRCs, compared with those who had not used these drugs. Low DRC or a family history of skin cancer increased the probability that patients who were overexposed to sunlight would have multiple BCCs. DNA repair levels may be influenced by the use of selected photosensitizing drugs and estrogen.

Adult↗
PubMed1994

Progression of basal cell carcinoma through loss of chromosome 9q and inactivation of a single p53 allele.

Basal cell carcinoma (BCC) of the skin represents a unique group of tumors strongly associated with exposure to UV light. Unlike squamous carcinoma of the skin, BCC is generally indolent, noninvasive, and rarely metastatic. To study the involvement of tumor suppressor genes in these neoplasms, we analyzed 36 BCCs for p53 mutations and a subset of these tumors for loss of chromosomes 17p and 9q. Sixty-nine % of sporadic BCCs had lost a 9q allele, with the common area of loss surrounding the putative gene for nevoid BCC or Gorlin's syndrome. Forty-four % (16 of 36) of BCCs had a mutated p53 allele, usually opposite pyrimidine tracts, which is consistent with UV-induced mutations. Surprisingly, only one tumor had lost a 17p allele, and in all BCCs only one p53 allele was inactivated. This is in direct contrast to other epithelial tumors, which usually progress by the inactivation of both p53 alleles.

Adult↗
PubMed1994

Vitamin supplementation and reduced risk of basal cell carcinoma.

A clinic-based case-control study was conducted to determine the association between vitamin supplement use and risk of basal cell carcinoma (BCC) of the skin. The subjects were 131 patients with histopathologically confirmed primary BCC and 200 cancer-free controls with non-premalignant skin disorders. Use of any vitamins (mainly multivitamins and vitamins A, C, and E) was associated with reduced risk of BCC. After controlling for age, sex, cigarette smoking, number of lifetime severe sunburns, and skin actinic elastosis, regular vitamin supplementation was associated with a significantly reduced risk of BCC (odds ratio (OR) = 0.3; 95% confidence interval (CI) = 0.2-0.06). The ORs decreased as the regularity (p < 0.001) and daily doses of supplement used increased, especially for vitamins A (p < 0.005) and E (p < 0.005). Vitamin supplementation was not associated with alterations in cellular DNA repair. These results, however, cannot be considered conclusive because of the relatively low participation rates (131/830 for cases and 200/1406 for controls) due to the requirement of blood donation and more rigorous studies are needed to clarify the effect of supplemental vitamins, particularly of vitamins A and E, on the risk of BCC of the skin.

Adult↗
PubMed1994

E-box- and MEF-2-independent muscle-specific expression, positive autoregulation, and cross-activation of the chicken MyoD (CMD1) promoter reveal an indirect regulatory pathway.

Members of the MyoD family of gene-regulatory proteins (MyoD, myogenin, myf5, and MRF4) have all been shown not only to regulate the transcription of numerous muscle-specific genes but also to positively autoregulate and cross activate each other's transcription. In the case of muscle-specific genes, this transcriptional regulation can often be correlated with the presence of a DNA consensus in the regulatory region CANNTG, known as an E box. Little is known about the regulatory interactions of the myogenic factors themselves; however, these interactions are thought to be important for the activation and maintenance of the muscle phenotype. We have identified the minimal region in the chicken MyoD (CMD1) promoter necessary for muscle-specific transcription in primary cultures of embryonic chicken skeletal muscle. The CMD1 promoter is silent in primary chick fibroblast cultures and in muscle cell cultures treated with the thymidine analog bromodeoxyuridine. However, CMD1 and chicken myogenin, as well as, to a lesser degree, chicken Myf5 and MRF4, expressed in trans can activate transcription from the minimal CMD1 promoter in these primary fibroblast cultures. Here we show that the CMD1 promoter contains numerous E-box binding sites for CMD1 and the other myogenic factors, as well as a MEF-2 binding site. Surprisingly, neither muscle-specific and the other myogenic factors, as well as a MEF-2 binding site. Surprisingly, neither muscle-specific expression, autoregulation, or cross activation depends upon the presence of of these E-box or MEF-2 binding sites in the CMD1 promoter. These results demonstrate that the autoregulation and cross activation of the chicken MyoD promoter through the putative direct binding of the myogenic basic helix-loop-helix regulatory factors is mediated through an indirect pathway that involves unidentified regulatory elements and/or ancillary factors.

Amino Acid Sequence↗
PubMed1994

[Studies on the efficacy of albendazole candy for treatment of intestinal nematode infections].

A single dose of albendazole (candy) 100 mg and 100 mg qd for two days was given respectively to 135 and 321 children who were infected with Enterobius vermicularis. All cases were cured 3wk later according to perianal tape examination. The same drug of 150 mg qd and 200 mg qd for two days was administered respectively to residents with single or multi-infections of Ascaris, hookworm and Trichuris; the egg negative conversion rates of the two dosages were revealed to be 99.4% (466/469) and 99.8% (487/488) for Ascaris infection, 96.8% (91/94) and 94.3% (99/105) for hookworm infection, and 53.4% (228/427) and 76.3% (370/486) for Trichuris infection. The maximal numbers of worm expelled were 100 on d2-3, 88 on d3-5 and 588 on d2-4 for Enterobius, Ascaris and hookworm, respectively; whereas the discharged Trichuris were scarce, merely 4.3 in average. The results exhibited promising efficacy of the drug on Enterobius, Ascaris and hookworm infections, but not so on trichuriasis.

Albendazole↗
PubMed1994

[Risk factors of prostate cancer--a matched case-control study].

A 1:2 matched case-control study was used to determine the risk factors of prostate cancer. Twenty-seven cases of prostate cancer were matched with an equal number of other malignant tumor cases (non-urological tumor) and other urological cases (non-malignant tumor). Both study and control groups were the same in age, sex, race, and day of admission. All of these patients were treated in the First Affiliated Hospital of West China University of Medical Sciences. The questionnaire was used to survey the both groups of patients. Such data as diet, lifestyle, marital status and past history of other prostate diseases were obtained. Single factor analysis and multiple conditional logistic regression analysis were used to estimate the relative risk (RR), 95% confidence interval (95% CI) and P values. Statistical analysis was performed using the Egret, Epilog soft ware. The results were as follows: 1. Increasing dietary vitamin A was associated with a significant decrease in the risk of prostate cancer (RR = 0.948, 95% CI = 0.9309-0.9947, P = 0.029). This factor also showed dose response gradients. The relative risk was decreasing with exposure dose increasing. 2. The positive previous prostate history, such as prostatitis and benign prostate hyperplasia, increased the risk of prostate cancer (RR = 6.385, 95% CI = 1.046-38.97, P = 0.045). 3. Another finding in the widower, divorce and remarried men (RR = 4.312, 95% CI = 1.367-13.6, P = 0.013). And 4. There was no relationship between the risk of prostate cancer and dietary fat intake, vasectomy, socioeconomic status, familial malignant tumor history, smoking and alcohol consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

Effect of dietary fish oil on acute light-induced photoreceptor damage in the rat retina.

PURPOSE: Previous studies have shown that ingestion of fish oil (FO) containing a high proportion of n-3 polyunsaturated fatty acids increases the susceptibility of cellular membranes to oxidative damage in various tissues. In the retina, lipid peroxidation is thought to be a major mechanism contributing to light-induced lesions. Therefore, we investigated the effect of FO on acute light-induced photoreceptor damage. METHODS: For 2 months, weanling rats were fed diets containing either soybean oil (SOY) or FO as main lipid component. RESULTS: Rats fed FO had significantly higher levels of eicosapentaenoic acid (EPA, 20:5n-3) and higher ratios of EPA to arachidonic acid (AA, 20:4n-6) in retinal phospholipids and diacylglycerols than rats fed SOY. The levels of docosahexaenoic acid (DHA, 22:6n-3) were similar in both dietary groups. The susceptibility to lipid peroxidation was enhanced in the isolated retina of FO-fed rats as shown by higher levels of thiobarbituric acid reactive substances after incubation of retinal membranes with Fe2+/ascorbate. The retinal content of alpha-tocopherol was similar in SOY- and FO-fed animals. Light damage consisting of acute rod outer segment (ROS) disruptions was induced by exposing dark-adapted animals to 600 to 700 lux (230 to 260 microW/cm2) of white fluorescent light for 30 minutes. Damage was quantitated using a computerized multifunctional image analysis of retinal thin sections. Although structural alterations of the ROS were present in both groups, FO-fed rats showed less damage at the base of the ROS. This occurred in spite of higher rhodopsin levels in FO-fed rats. There was no effect of diet on retinal morphology in dark-adapted rats. CONCLUSION: These results indicate that FO does not enhance the susceptibility to acute ROS disk disruptions in the rat retina. Our study further suggests that FO exerts a partial protective effect that may be related to changes in the formation of lipid mediators derived from EPA and AA in retinal phospholipids.

Acute Disease↗
PubMed1993

DNA repair and aging in basal cell carcinoma: a molecular epidemiology study.

This molecular epidemiology study examines the DNA-repair capacities (DRCs) of basal cell carcinoma (BCC) skin cancer patients (88) and their controls (135) by using a plasmid/host-cell reactivation assay. In this assay UV-damaged expression vector plasmid is transfected into peripheral blood T lymphocytes from the subjects. The host-cellular repair enzymes repair the photochemical damage in the plasmid, and 40 hr later the plasmid-encoded reporter chloramphenicol acetyltransferase is measured. An age-related decline in this DRC, amounting to approximately 0.61% per yr occurred in the controls from 20 to 60 yr of age. Reduced DRC was a particularly important risk factor for young individuals with BCC and for those individuals with a family history of skin cancer. Young individuals with BCC repaired DNA damage poorly when compared with controls. As the BCC patients aged, however, differences between cases and controls gradually disappeared. The normal decline in DNA repair with increased age may account for the increased risk of skin cancer that begins in middle age, suggesting that the occurrence of skin cancer in the young may represent precocious aging. Patients with reduced DRCs and overexposure to sunlight had an estimated risk of BCC > 5-fold greater than the control group. Such a risk was even greater (10-fold) in female subjects.

Adult↗
PubMed1993

Enhanced detection of normal retinal nerve-fiber striations using a charge-coupled device and digital filtering.

We used a 1024 x 1024 pixel, 15-microns, 16-bit-encoding, multi-pin-phase charge-coupled device (CCD) to obtain images of the normal human retinal nerve fiber layer. This device, which operates at room temperature, offers significantly better signal-to-noise ratio, linearity, and dynamic range than do photographic film, video imaging techniques, or commercially available CCDs. We demonstrate the use of a nonlinear digital filter, together with filter windows, that enhances fine detail of NFL striations, while suppressing noise, in limited areas of the CCD images. High-sensitivity imaging of this type, together with appropriate digital processing, may prove useful in diagnosing and following nerve-fiber-layer damage due to glaucoma.

Fundus Oculi↗
PubMed1993

Dimerization specificity of myogenic helix-loop-helix DNA-binding factors directed by nonconserved hydrophilic residues.

The myogenic regulatory factor MyoD dimerizes with other positive and negative regulatory factors through a conserved region called the helix-loop-helix (HLH) domain. Using a non-DNA-binding MyoD mutant with a normal HLH domain as a dimerization competitor in gel mobility shift assays in conjunction with various MyoD HLH mutants, nonhydrophobic amino acids were identified in the HLH domain that contribute to dimerization specificity with E12. The assay detected subtle differences in dimerization activity among the mutant MyoD proteins that correlated with their ability to activate transcription in vivo, but this correlation was not apparent in the absence of competitor. The identification of such nonhydrophobic residues enabled us to predict the differences in dimerization affinity among the four vertebrate myogenic factors with E12. The experiments confirmed the prediction. Furthermore, a high-affinity homodimerizing analog of MyoD was designed by a single substitution at one of these residue positions. These experimental results were strengthened when they were analyzed in terms of the crystal structure for the Max bHLHZip domain homodimer. This analysis has allowed us to identify those residues that form charged residue pairs between the two HLH domains of MyoD and E12 and determine the dimerization specificity of the bHLH proteins.

Amino Acid Sequence↗
PubMed1992

Time-resolved spectroscopy of the human forearm.

For spectroscopic purposes, the forearm is a conveniently large object to be investigated because consistent oxygenation and blood volume changes can be obtained. Human forearm spectral properties were investigated using picosecond near-IR laser spectroscopy. The behaviour of the temporal point spread function in resting conditions and during ischaemia, venous occlusion and exercise is reported. The effect of path length inaccuracy on muscle oxygen consumption, obtained by combining spectral data with the path length, is discussed.

Adult↗
PubMed1992

Light and lithium effects in the rat retina: modification by the PAF antagonist BN 52021.

We tested the effect of an antagonist of platelet-activating factor (PAF), BN 52021, on both acute light-induced and light plus lithium-induced rod outer segment (ROS) lesions. Rats were fed lithium carbonate (2.6 g/kg chow) for 3 weeks. Half of the lithium-treated rats received BN 52021 (25 mg/kg) via gastric intubation prior to light exposure. Control and treated rats were exposed to 400-450 lux (measured at the eye level of the rats) of diffuse, white fluorescent light for 30 min, followed by 2 h of darkness and then decapitated. The eyes were removed and prepared for light and electron microscopic observation. The structural alterations of ROS were quantified from electron micrographs using a multifunctional computer image-analysis system. Our data show a significant reduction of ROS lesions by BN 52021, and this is most pronounced in light plus lithium-treated rats. Furthermore, in confirmation of previous studies, chronic lithium treatment significantly augmented light-elicited phagosome numbers, and BN 52021 reduced this effect. Our findings thus suggest that light and lithium may act via PAF responses in the rat retina.

Analysis of Variance↗
PubMed1992

Risk factors for increased airway responsiveness to methacholine challenge among laboratory animal workers.

As a first step in a prospective study of the incidence of asthma to laboratory animals, a group of 364 adults 18 to 48 yr of age who were beginning employment with laboratory animals were evaluated in terms of their past history, health status, allergy, and airway responsiveness to methacholine. At entry to the study, 269 had previous occupational contact with animals, 109 had chest symptoms in the previous year, 168 had a history of allergic symptoms to laboratory animals (any with asthmatic responses were systematically excluded), and 118 had positive immediate skin tests (29 had positive skin tests to laboratory animals). When defined as a PD20FEV1 of 80 breath units or less, 18.4% of these young adults had methacholine hyperresponsiveness (HRA). Significant risk factors for HRA were found to be younger age, female sex, lower educational level, a history of allergic symptoms to laboratory animals, and a history of chest symptoms. Positive skin tests to laboratory animals were present in 8% of workers; this was not a significant risk factor for HRA although positive skin tests to pollen and household allergens were. Previous work experience was a risk factor, especially among those with allergic symptoms, and a trend toward self-selection was suggested in that the rate of HRA was lowest in workers with more than 2 yr of experience or with two or more previous jobs with laboratory animals.

Adolescent↗
PubMed1992

Diagnostic value of serum gamma-glutamyl transferase isoenzyme for hepatocellular carcinoma: a 10-year study.

Serum gamma-glutamyl transferase (GGT) was separated into nine to 11 isoenzyme bands (designated as GGT I-XI) by vertical slab electrophoresis on polyacrylamide gradient gel. The diagnostic value of GGT isoenzyme II (GGT II) for hepatocellular carcinoma (HCC) was studied, and the results were as follows: 1) GGT II was positive in 90% of 90 cases of HCC, and negative in most patients with acute and chronic viral hepatitis, extrahepatic tumors, in pregnant women, and in healthy controls; 2) the positive rate of GGT II assay was higher than that of alkaline phosphatase isoenzyme I (ALP I), alpha-fetoprotein (AFP), and alpha 1-antitrypsin (AAT) in 101 cases of HCC. In cases in which the AFP was greater than 50 ng/ml or less than 50 ng/ml, the positive rates of GGT II were 70.8% and 75-100%, respectively; 3) of 14 cases of small-size HCC, the positive rate of GGT II was 78.6%, which was higher than that of AFP (50%), AAT (28.6%), and ALP I (0%); 4) of 62 cases that were false-positive for GGT II assay, 24.2% developed into HCC during a follow-up of 2.1-20 months. In subjects with persistent and recurrent positivity of GGT II, 86.7% and 22.2%, respectively, developed HCC. No patient with temporal positivity of GGT II developed HCC. The results show that GGT II can be applied as an additional marker for HCC, and is valuable not only for the diagnosis of clinical HCC, but for the detection of small or subclinical HCC. Periodic follow-up with assay of GGT II in patients at high risk for HCC may predict the development of hepatoma.

Biomarkers, Tumor↗