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Biomedical subjects

W Q Chen

Publications and source records attributed to W Q Chen.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Experience in the surgical treatment of hepatic hydatidosis].

Of 1290 cases of hydatidosis hospitalized, 907 (70.3%) cases of hepatic hydatid cyst (HHC) were treated surgically (1954-1990). Of the 907 cases, 484 (53.3%) were males and 423 (46.7%) females. Hepatic hydatid cysts were single in 54%, multiple in 21.2% and complicated with hydatid cysts of other organs in 24.8%. 67.5% of the cysts were in the right lobe of the liver, 15.6% in the left lobe, 16.9% in both lobes. 79.0% were situated in the right lower part of the liver, 21.0% on the dome of the liver. Rupture of the cysts into biliary system, peritoneal cavity, the thorax (pulmonary-bronchial tree) and the pericardial sac were 35 (30%), 50 (42.6%), 31 (26.5%) and 1 case (0.9%) respectively. There were 5 deaths. Our experiences include: (1) routine intravenous drip of corticosteroids to alleviate the possible occurrence of allergic reaction during the operation and postoperative hyperpyrexia. (2) mebendazole or albendazole (ABZ) 20 mg/kg/d for one week before operation and 1-2 courses (1 course = 30 days) after operation to destroy the protoscoleces left in the body during operation. (3) antibiotics administration in complicated cases. (4) closure of intrahepatic biliary fistula.

Adolescent↗
PubMed1993

Serum osteocalcin and vitamin D in postmenopausal diabetic azotemics.

To clarify the role of serum vitamin D and bone remodeling markers in postmenopausal diabetic azotemics, we designed a study involving 3 different postmenopausal patient groups. Group I consisted of 20 diabetic women with renal insufficiency who were not yet on dialysis therapy. Group II consisted of 15 age-matched nondiabetic women with comparable degrees of renal insufficiency. Group III consisted of 20 age-matched women with normal renal function. We investigated the overnight fasting serum 25 (OH) vit-D, 1,25(OH)2 vit-D3, osteocalcin (OC), bone isoenzyme of alkaline phosphatase (ALK-PB) and intact parathyroid hormone (I-PTH) levels in these cases. The serum I-PTH and OC levels were statistically significantly higher, whereas 1,25(OH)2vit-D3 were significantly lower in Group I and Group II patients than in Group III patients. We found no significant correlation between elevation of I-PTH and reduced 1,25(OH)2 vit-D3 levels in Group I and Group II patients. I-PTH levels correlated positively with OC in Group I and Group II patients. There was no significant difference in serum 25(OH) vit-D among these 3 groups of patients. We conclude that (1) serum OC level may serve as a good parameter in evaluating secondary hyperparathyroidism in postmenopausal azotemics with or without diabetes, (2) even in the presence of menopause, renal failure per se is the main factor in determining serum 1,25(OH)2 vit-D3 levels in diabetic azotemics.

Aged↗
PubMed1993

Sequence length and error analysis of Sequenase and automated Taq cycle sequencing methods.

We have examined DNA sequence error as a function of length using both a manual method of performing reactions with Sequenase and an automated Taq cycle sequencing method. DNA fragments from both methods were separated and analyzed on a sequencer. To determine the sequence of a cosmid insert (35.3 kb), 379 sequences were obtained from a manual Sequenase method, and 354 sequences were obtained from a Taq cycle sequencing method as performed on an automated robotic workstation and sequenced on an automated fluorescent sequencer. A highly redundant consensus of these sequences was obtained and aligned with the individual sequences to determine sequence error over the length of each sequence. The results of this study indicate that error is about 1% per position over the first 350 nucleotides, but increases thereafter to about 17% at 500 nucleotides. This pattern of accuracy was nearly equivalent for manual Sequenase methods and automated Taq cycle sequencing methods. The potential of these methods in large-scale DNA sequencing projects is discussed.

Cloning, Molecular↗
PubMed1992

High-level expression in Escherichia coli and rapid purification of enzymatically active honey bee venom phospholipase A2.

Bee venom phospholipase A2 (BV-PLA2) is a hydrolytic enzyme that specifically cleaves the sn-2 acyl bond of phospholipids at the lipid/water interface. The same enzyme is also believed to be responsible for some systemic anaphylactic reactions in bee venom sensitized individuals. To study the structure/function relationships of this enzyme and to define the molecular determinants responsible for its allergenic potential, a synthetic gene encoding the mature form of BV-PLA2 was expressed in Escherichia coli. This enzyme was produced as a fusion protein with a 6xHis-tag on its amino-terminus yielding 40-50 mg of fusion protein per 1 of culture after metal ion affinity chromatography. A kallikrein protease recognition site was engineered between the 6xHis-tag and the amino-terminus of the enzyme allowing isolation of the protein with its correct N-terminus. Recombinant affinity purified BV-PLA2 was refolded, purified to homogeneity, and cleaved with kallikrein, resulting in a final yield of 8-9 mg of active enzyme per 1 of culture. The enzymatic and immunological properties of the recombinant BV-PLA2 are identical to enzyme isolated from bee venom indicating a native-like folding of the protein.

Amino Acid Sequence↗
PubMed1992

Sequence accuracy of large DNA sequencing projects.

Very little information has been accumulated regarding the likely accuracy of final or consensus DNA sequence data. With the large-scale efforts anticipated for the Human Genome Project, the subjective determination of final sequence must eventually be replaced with more objective, automatic methods. This will require a much better understanding of the nature of error in raw sequencing data and its impact on the determination of the final sequence. This paper describes a start at defining the error model of large-scale sequencing efforts based on random subcloning strategies.

Consensus Sequence↗
PubMed1992

[Effects of Se-enriched malt cakes on UV benzo(a)pyrene induced unscheduled DNA synthesis of lymphocytes from high risk population of lung cancer].

Se-malt cakes containing 300 micrograms selenium were given daily to men from high risk area of lung cancer and the influence of ultraviolet light (UV) and be benzo(a)pyrene (B(a)P) induced unscheduled DNA synthesis (UDS) of peripheral lymphocytes were determined. After Se-supplementation for 6 months, the Se levels in serum, hairs and activity of GSH-px were increased by 89%, 67% and 178%, respectively. The ratio of UV-induced UDS was decreased from the mean value of 2.47 in the control to 1.61 (P < 0.05) in the Se-group. After Se-intake for one year, the Se levels were elevated by 78% in serum, 83% in hairs and 56% in GSH-px activity, while the mean value of B alpha P-induced UDS was reduced from 2.21 in the control to 1.47 (P < 0.05) in the Se-group. The results of the present study indicate a blocking effect of Se-supplementation to UV- and B alpha P-induced UDS of peripheral lymphocytes from high risk subjects for lung cancer.

Adult↗
PubMed1992

[Surgical management of complicated pulmonary hydatidosis].

1954-1988, 680 patients with pulmonary hydatid cysts were operated upon at our hospital. 320 of the patients were classified as having complicated pulmonary hydatidosis (CPH). The criteria for CPH are as follows: (1) huge in size, occupied 2/3 or one side of the chest; (2) ruptured hydatid cyst or cysts, with or without secondary infection; (3) multiple lesions involving both lungs, sometimes combined with liver involvement; (4) the presence of hepato-pleural and/or hepato-bronchial fistulae. We advocated intact endocystectomy and saucerization of the residual actocystic pit for individual lesion. The diagnosis and management of different CPH, especially those with hepato-pleural or hepato-bronchial fistulae were discussed in detail. There were 2 operative deaths. The mortality rate of the whole series was 0.29%, and of those with CPH was 0.6%.

Bronchial Fistula↗
PubMed1990

Intervention trial with selenium for the prevention of lung cancer among tin miners in Yunnan, China. A pilot study.

This pilot study evaluated the feasibility and effectiveness of conducting a double-blind clinical trial for the prevention of lung cancer with selenium (Se) in Yunnan Tin Corporation, the People's Republic of China, where the incidence rates of lung cancer are extraordinarily high among the miners. Forty healthy miners were randomized to either 300 micrograms of Se in high Se malt cakes or an identical placebo of malt cakes daily for one year. Subjects consumed their usual daily diet. The low Se concentrations in plasma (0.05 +/- 0.008 microgram/mL) and hair (0.442 +/- 0.085 microgram/g) reflected their low dietary Se intake in the control subjects. In Se-supplemented group, the Se status was increased by 178% for serum and 194.8% for hair. The serum GSHpx activity was increased by 155.7%, whereas the lipid peroxide level was reduced by 74.5% compared to the placebo. The results of UDS assay indicated that the lymphocyte DNA damage induced by ultraviolet irradiation and carcinogen 3,4-benzpyrene could be protected by Se supplementation. Se-supplementation did not affect the liver function test (SGPT), as well as the concentrations of hemoglobin, albumin, and cholesterol. Thus, daily intake of 300 micrograms Se in form of Se-malt as a chemopreventive measure is safe and effective to humans with low Se status.

Adult↗
PubMed1989

[Pharmacologic study of Curculigo orchioides Gaertn].

The experiments showed that ethanolic extract of Curculigo orchioides had adaptive effects, such as enhancing tolerance towards high temperature and hypoxia. It also had sedative, anticonvulsant and androgen-like effect. Besides, it increased the immunological activity of mice.

Adaptation, Physiological↗
PubMed1987

NMR studies of backbone-alkylated DNA: duplex stability, absolute stereochemistry, and chemical shift anomalies of prototypal isopropyl phosphotriester modified octanucleotides, (Rp,Rp)- and (Sp,Sp)-(d-[GGA(iPr)ATTCC])2 and -(d-[GGAA(iPr)TTCC])2.

The DNA octamer (d-[GGAATTCC])2 and four alkylated analogues, (Rp)-(d-[GGA(iPr)ATTCC])2, (Sp)-(d-[GGA(iPr)ATTCC])2, (Rp)-(d-[GGAA(iPr)TTCC])2, and (Sp)-(d-[GGAA(iPr)TTCC])2 have been examined using 1H and 31PNMR spectroscopies. Duplex stability, as monitored by both NMR and optical measurements, is shown to be a function of both site and stereochemistry of the phosphotriester moiety. Chemical shift changes relative to the native octamer indicate that there are long-range perturbations in the isopropylated molecules. 1HNMR is shown to be a general means by which stereochemistry at phosphorous can be determined.

Alkylating Agents↗