Biomedical subjects

C Chen

Publications and source records attributed to C Chen.

At least 613 records · Page 34Linked to original sources

PubMed1998

Downstream technique study of human tumor necrosis factor alpha and its mutant.

The study of downstream techniques for recombinant human necrosis factor alpha (rhTNF alpha) and its mutant (Lys2)-rhTNF alpha led to the results of approximately 50 g wet recombinant E. coli per liter with high expression level (> 50%) harvested from autocontrolled fed-batch culture in 15 L fermentor (B. Braun). The rhTNF alpha and (Lys2)-rhTNF alpha expressed are totally soluble. Followed by the process of ultrasonication, ammonium sulfate precipitation, ion-exchange chromatography (DEAE-sepharose FF, CM-sepharose FF), and molecular sieve (Sephacryl S-200), a yield of approximately 1 g pure recombinant protein from 1 L broth is obtained. The purity is up to 98%. The specific activity of rhTNF alpha and (Lys2)-rhTNF alpha are approximately 1.5 x 10(8) IU/mg and approximately 6 x 10(8) IU/mg, respectively.

Escherichia coli↗

PubMed1998

Transurethral prostate vaporization using an oval electrode in 82 cases of benign prostatic hyperplasia.

OBJECTIVE: To present our initial experience in transurethral vaporization of the prostate (TVP) using an oval electrode for the treatment of benign prostatic hyperplasia (BPH). METHODS: A total of 82 patients underwent TVP procedures with the oval electrode. The newly designed oval-shaped electrode can work with a High Frequency Electrosurgery Unit. Prostate gland tissue was vaporized through an Fr 24 percutaneous nephroscope transurethrally. The operation procedure was similar to transurethral resection of the prostate (TURP) or transurethral laser prostatectomy (TULP). Power setting ranged from 240 W to 320 W. Local vaporization temperature reached 120 degrees C. RESULTS: Urination was recovered in all 82 patients after TVP. Mean post-treatment International Prostate Symptom Score (I-PSS) reduced from 27.10 to 5.05; mean bladder residual urine volume dropped from 147.71 ml to 33.2 ml; and mean urine flow rate (MFR) increased from 4.45 ml/s to 14.57 ml/s (P < 0.01). The initial results of short-term follow-up were excellent. CONCLUSIONS: TVP with the oval electrode is easy to perform and causes less hemorrhage and few complications. It especially benefits elderly and/or critically-ill patients. We believe that TVP with our oval electrode is feasible with low risk.

Aged↗

PubMed1998

[Relationship between body surface zinc loss and dietary zinc intake in children].

OBJECTIVE: To study the effects of body surface loss of zinc on the determination of dietary supply of zinc. METHODS: Body surface loss of zinc was determined in 24 preschool children with normal zinc nutrition (Group A) and zinc malnutrition (Group B). RESULTS: Body surface loss of zinc was 0.25 and 0.23 mg daily in Groups A and B with dietary zinc intake of 5.45 and 5.03 mg, respectively, and 0.29 and 0.25 mg daily with dietary zinc intake of 7.20 and 6.73 mg, respectively. The body surface loss of zinc accounted for five percent of the total. CONCLUSION: Considering the loss of zinc from body surface, it is suggested that dietary zinc supply be increased by 21 percent. When children is in good status of zinc nutrition, body surface loss of zinc correlates proportionally with their dietary zinc intake.

Child↗

PubMed1998

[Studies on hygienic standard for ozone in indoor air].

OBJECTIVE: To formulate a national hygienic standard for ozone in indoor air. METHODS: Indoor air ozone concentrations at variety of places were detected at its peak level in the daytime. Also, animal experiments exposed to low-level ozone were conducted to study the contents of lipid peroxide in the lungs, the ultrastructure of the bronchial epithelium and the phagocyte function of peritoneal macrophage. RESULTS: Safety of ozone concentration of 0.1 mg/m3 in indoor air and feasibility to use it as hygienic standard were tested and proved. CONCLUSION: The national hygienic standard for ozone in indoor air is recommended at 0.1 mg/m3 based on the data and relevant criteria at home and abroad.

Air Pollution, Indoor↗

PubMed1998

A better long-term outcome in cardiac transplant recipient with a history of previous open heart operations.

OBJECTIVE: To investigate the effect of previous open heart operations (POHO) on the outcome of heart transplantation (HTX). METHODS: Between November 1984 and May 1996, HTX was performed on 151 patients at Hartford Hospital. Among them, 61 patients had previous open heart operations (POHO) (group A), and 90 did not (group B). The average follow-up period was 1615 +/- 1185 days for group A and 1330 +/- 1125 days for group B. The recipient age was 55 +/- 10 years for group A and 48 +/- 12 years for group B (P < 0.01). There were 17 patients (26%) in group A and 14 (50%) in group B who were over 60 years of age. There was more coronary artery disease (74% versus 37%, P < 0.001) as etiology, and more diabetics in group A (P < 0.02). RESULTS: The time for cardiopulmonary bypass (133 +/- 20 min versus 106 +/- 18 min, P < 0.01) and aortic clamp time (73 +/- 16 min versus 61 +/- 13 min, P < 0.01) were longer in group A. The operative mortality (within 30 days) was 0 and 2.2%, and the cumulative deaths were 16 (26%) and 43 (48%) respectively for group A and group B (P < 0.01). The causes of death were (group A vs group B): infection (31% vs 26%), rejection (13% vs 28%, P < 0.05), malignancy (25% vs 16%), cardiac event (6% vs 14%) and others (25% vs 16%). In patients over 60, there were 4 deaths (24%) in group A and 7 (50%) in group B. The difference was not significant. No patients died of rejection in this subgroup. The actuarial survival rates in group A versus group B were: 1 year, 93% versus 83%; 2 years, 85% versus 74%; 3 years, 81% versus 71%; 5 years, 76% versus 58%; and 10 years, 57% versus 24% (P < 0.01). CONCLUSION: The survival rate in patients who had POHO is much higher than that in patients who had HTX as their primary operation.

Adolescent↗

PubMed1998

Production of human recombinant bone morphogenetic protein-2A by high density culture of Escherichia coli with stationary dissolved oxygen fed-batch condition.

The optimization of cultivation condition in 500 ml shake flasks was carried out to produce recombinant human bone morphogenetic protein-2A (BMP-2A) in recombinant Escherichia coli YK537/pDH-B2m, followed by a 5L fermenter batch and condition-controlled fed-batch culture to obtain BMP-2A. The comparison of these two methods indicated that cultivation by keeping dissolved oxygen at 30%-40% and limiting glucose concentration could obtain BMP-2A 2.78 g/L broth, the final cell density was OD600 53 (dry cell weight 21.2 g/L), and expressed BMP-2A was 25% of the total amount of protein in E.coli. The critical fermentation conditions included: (1) keeping appropriate dissolved oxygen concentration in the process; (2) limiting glucose concentration; (3) taking heat induction at the middle-log phase and maintaining 42 degrees C for 4 hours; (4) controlling specific growth rate around 0.3 h-1 in the duration of growth.

Bone Morphogenetic Protein 2↗

PubMed1998

[Dynamic enhanced MR imaging of intraspinal tumors].

The dynamic enhanced MR imaging of 37 patients with intraspinal tumors were performed. We found that the enhancement peak within 90s was shown only in hemangioblastoma, within 180s was shown in most astrocytomas, meningiomas, and metastases. The maximum contrast enhancement ratio (MCER) of neurilemmoma is higher than that of meningioma(P > 0.05). We conclude that the contrast enhancement ratio-time(CER-T) curve, the enhanced degree, and pattern of intraspinal tumors have the significant value for the histologic diagnosis and the calculation of vascularity.

Adolescent↗

PubMed1998

[The second phase clinical observation of anti-radiation effect by superoxide dismutase].

Multiple center randomized controlled double blind clinical trait was conducted to evaluate the anti-radiotherapy effect by SOD (produced by Hunan Biochemical Work) in 159 patients. Injection of 4000U SOD immediately after receiving radiotherapy significantly reduced the occurrence rate of skin, oral mucosal, pelvic visceral and systematic adverse reaction, only the reduction of leukopenia did not reach the statistical significant level. No adverse effect of SOD injection was observed. The results suggest that SOD is a safe and effective agent to attenuate the radiotherapy reactions.

Adolescent↗

PubMed1998

[Experimental study on hypoglycemic effect of YTY granules].

OBJECT: To perform experimental pharmacodynamic evaluation of a new TCM antidiabetic drug Yitangyin (YTY). METHODS: Experimkental streptozotocin induced rat diabetes models were subjected YTY treatment and the hypoglycemic effect was evaluated. The proved TCM Yusanxiao (YSX) was used as contrast. RESULTS: The low, middle and high dose YTY groups exhibited significant hypoglycemic effects on the model rats. The efficiency was comparable with YSX. CONCLUSION: The TCM YTY granule is an effective hypoglycmeic agent.

Animals↗

PubMed1998

[Detection of human papillomavirus infection in cervical Pap smears by computer-assisted cytologic test].

OBJECTIVE: The sensitivity and accuracy of cytologic computer-assisted test (CCT) in diagnosis of human papillomavirus (HPV) infection in cervical Pap smear were evaluated. METHODS: Cervical Pap smears obtained from 158 patients with vulva condyloma acuminata were examined by CCT. The diagnostic criteria were based on The Bethesda System (TBS). Simultaneously HPV DNA in cervical mucus was examined by polymerase chain reaction (PCR) technique and cervical biopsy taken under the guidance of colposcopy for pathological examination. RESULTS: The sensitivity and accuracy of CCT in diagnosis of cervical HPV infection were 74.62% and 67.72% compared with pathological results whereas 69.11% and 70.88% compared with PCR results respectively. CONCLUSION: The results indicates that CCT, a cytologic pathological technique, is a useful method in diagnosis of clinical and subclinical cervical HPV infection.

Cervix Uteri↗

PubMed1998

[Detection of sister chromatic exchange in workers exposed to coal tar pitch and to coke oven volatiles].

In order to know the changes of genetic toxicological effects on workers occupationally exposed to polycyclic aromatic hydrocarbons (PAHs), sister chromatic exchange(SCE) was detected by the methods of peripheral lymphocyte culture in 23 workers exposed to coal tar pitch (CTP) and in 19 workers exposed to coke oven volatiles (COV) and 12 normal controls. The results suggested that the SCE in occupational workers was significantly higher than that in controls (11.31 vs 6.37, P < 0.001). The SCE in workers exposed to CTP and to COV was higher than that of control (10.27 and 12.58 vs 6.37) respectively. In workers exposed to CTP and COV, there were no differences of SCE for smokers and nonsmokers (P > 0.05). It is indicated that CTP and COV caused strong genetic toxicity and injury to chromosome.

Adult↗

PubMed1998

[Detection of microcystins in source and tap water from a lake].

The microcystins in source and tap water collected from seven waterworks around a lake in summer, 1996 were detected by enzyme-linked immunosorbent assay (ELISA). Microcystins were determined in the source water from all the seven waterworks, and the concentrations ranged from 280 to 35,300 ng/L. Low concentrations of microcystins were also detected in the tap water of three waterworks. The results suggest that microcystins in source water could not be removed completely by conventional adding bleaching powder treatment.

Bacterial Toxins↗

PubMed1998

[Genetic epidemiological study of asthma in general].

With theory and method of genetic epidemiology, data of 641 nuclear families on asthma were analysed, and the results showed that the history of parents asthma was one of risk factors about offsprings asthma, and the risk was 4.0-8.0 times higher (P < 0.01), compared with the one of offsprings of parents with no asthma. The effect of parents with asthma on the risk of sons was the same as one of daugters. The result declared that the airway responsiveness of parents did not relate to the one of offsprings. The results suggest that the genetic factors play an important role in the asthma.

Adolescent↗

PubMed1998

[Calculating method for the necessary lamps and sterile rate in a tube-shaped ultraviolet air washer].

It has much more advantage to use the cylindric ultraviolet air washer than to use the ordinary ultraviolet lamps. There was a calculation method for determining necessary lamps in a rectangled ultraviolet air washer, but it had a limiting condition. This paper developed two calculating methods for determining necessary lamps and its sterile rate in a tube-shaped ultraviolet air washer. The sterile rate can be extracted with any parameter. Necessary lamps can also be extracted with its sterile rate.

Air Microbiology↗

PubMed1998

[Changes of erythrocyte and platelet membrane lipid pattern in different subtypes of dementia].

OBJECTIVE: To investigate the changes of platelet and erythrocyte membrane lipids and phospholipid composition in different types of dementia. METHODS: There were 19 patients with Alzheimer's disease, 25 patients with Binswanger's disease, 23 patients with multi-infarct dementia, 11 patients with single cortical infarct dementia, 7 patients with vascular dementia of haemodynamic type, 18 patients with dementia following Parkinson's disease, and 25 senile controls. Platelet and erythrocyte membrane cholesterol, total phospholipids and individual phospholipids were quantified. RESULTS: When compared with senile controls, the decrease of total phospholipids, phosphatidylcholine and phosphatidylethanolamine and the increase of cholesterol and cholesterol/total phospholipids ratio on the erythrocyte and platelet membrane were found in patients with Binswanger's disease and in those with multi-infarct dementia. The increase of erythrocyte and platelet membrane cholesterol, cholesterol/phospholipids ratio was found, but there was no significant change in membrane total phospholipids and phospholipid composition in patients with single cortical infarct dementia. CONCLUSION: Metabolic disorders of platelet and erythrocyte membrane phospholipids were noted in patients with Binswanger's disease. These disorders were related to white matter low attenuation.

Aged↗

PubMed1998

[The clinicopathological study on 41 cases of cardiac tumors].

OBJECTIVE: To analyze the relation between the pathological changes and the prognosis of cardiac tumors through the clinicopathological study on 41 cases of cardiac tumors. METHODS: The study was carried out by using the common and special histochemical stainings. RESULTS: 39(95.1%) tumors were benign, including myxoma, fibroma, and rhabdomyoma; while 2(4.9%) tumors were malignant, including neurofibrosarcoma and malignant mesothelioma. In the myxomas group, 75% patients were female, 91.7% tumors existed in the left atrium. CONCLUSIONS: The results of the clinicopathological study showed that the cardiac tumors were quite different from the tumors in the other sites, i.e. even benign ones could cause fatal hemodynamic disturbance, hence early diagnosis and early operation are necessary. The prognosis of the malignant tumors is worst.

Female↗

PubMed1998

[A study of the correlations between asthma and airway responsiveness].

OBJECTIVE: To evaluate the effect of airway responsiveness on asthma and to study the causes of asthma. METHODS: The 641 nuclear families were confirmed by indicator cases with asthma in three counties. Investigation and methacholine challenge test were conducted for all relatives of the nuclear families. The data were by EPI5.01 and the odds ratio (OR) was employed to evaluate the correlation between asthma and airway responsiveness. RESULTS: 72 percent of persons with asthma history showed airway hyperresponsiveness, but only 70 per cent of persons with airway hyperresponsiveness suffered asthma. The risk for asthma in relatives with positive airway responsiveness was 5.8 times higher than those with negative airway responsiveness (P > 0.01) among the nuclear families. CONCLUSION: Airway hyperresponsiveness is one of the risk factors of asthma.

Adolescent↗

PubMed1998

[Expression of cell adhesion molecule CD44 variant isoform correlated with the clinical behavior of renal cell carcinoma].

OBJECTIVE: To determinate whether the expression of CD44v in renal cell carcinoma (RCC) is associated with tumor malignant behavior. METHOD: Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect CD44v in 31 human renal cell carcinoma (RCC) in addition to 18 normal renal tissues from patients with non-malignant disease. RESULT: Eighteen RCCs showed positive expression while none of normal renal tissue expressed CD44v (P < 0.001). CD44v was expressed in metastatic or high pathological stage RCC, but the expression of CD44v was not correlated with cellular differentiation. CONCLUSION: Our data indicate that a role for CD44v in human RCC progression and metastases, and CD44v may prove to be a marker for high metastasis potential of RCC.

Adult↗