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Biomedical subjects

G W Chen

Publications and source records attributed to G W Chen.

28 records · Page 2Linked to original sources
PubMed1992

[Cushing's syndrome with pregnancy. Report of three cases].

Cushing's syndrome with pregnancy is rare, and only about 60 cases have been reported. In the recent 4 years, 3 cases were diagnosed in Chang Gang Memorial Hospital. They presented with serious maternal complications early in the second month of pregnancy, including hypertension, proteinuria and lower leg edema. Unfortunately it was not diagnosed until the 20th week of pregnancy. They had the same hormone profile as other Cushing's syndrome patients who were not pregnant. Under the supportive treatment they had outcomes of two premature deliveries and one still birth. Just after delivery all patients received left adrenalectomy and pathology showed adenoma. All of them had good recovery courses. According to the literature, early treatment (surgical operation, medical treatment, or irradiation) could decrease maternal morbidity and fetal loss rate.

Adult↗
PubMed1990

[Growth catch-up in the case of congenital hypothyroidism after delayed treatment--a case report].

We report a case of congenital hypothyroidism, presenting with growth and mental retardation since childhood, but in which the diagnosis was not made until he was 17 years old. Because of such an unusually long delay in treatment, we focussed on the growth catch-up. This included the change of skeletal growth, puberty and mentality after a 4-year treatment period. He was 114 cm in height (height age 5.5 years) with the upper segment measuring 60 cm and lower segment 54 cm (U/L ratio 1.1). His bone age was that of a six year old and he had no secondary sexual characteristics. IQ testing showed a full scale IQ of 68, verbal IQ 74 and performance IQ 64. After 4 years of treatment, his height caught up to 152 cm (height age 12.5 years), with the upper segment 77.2 cm, and that of lower segment 74.8 cm (U/L ratio 1.03). The bone age had advanced to that of a 17 year old. His pubic hair emerged after 18 months of therapy (at a chronologic age of 18.5 years), accompanied by a normalization of testosterone and a normal response to a GnRH test. His IQ test was rechecked after 2 years of treatment. His full scale IQ was 78, verbal IQ 77 and performance IQ 83. In the mean time, the patient got a job being more alert, active and self-confident following his growth catch-up.

Adolescent↗
PubMed1984

Formulas for preparing phantom muscle tissue at various radiofrequencies.

The dielectric properties of various test samples of phantom tissue were measured using an automated and temperature-controlled slotted line. The ingredients for phantom materials were determined for simulating high-water content tissue at 13.56, 27.12, 40.68, 70, 100, 200, 300, 433, 750, 915, and 2,450 MHz. The ingredients consisted of water, TX-150 (a gelling agent), sodium chloride, and polyethylene powder (200-2,450 MHz) or aluminum powder (13.56-100 MHz). The dielectric constant and conductivity of these materials at different temperatures (15, 22, 30 degrees C) were characterized.

Hot Temperature↗
PubMed1983

Sequential external counterpulsation (SECP) in China.

A new SECP was developed and is currently successfully used in more than 120 clinics in China. This sequenced counterpulsation device has the effect of milking more blood as pressure is applied on the extremities in succession (first distally then proximally) and in decreasing values (265 to 200 mm Hg). In comparison of the 4 types of counterpulsation, namely nonsequenced leg and 4 limb counterpulsation, and sequenced 4 limb and 4 limb with buttock balloons, the SECP with buttock balloons method raised the DA to appreciably higher levels with respect to DA amplitude and area. DA was raised 43.9% higher than that obtained with 4 limb SECP alone. From our experimental and clinical results, we conclude that SECP with buttock balloons is a far more effective method providing greater diastolic augmentation than previously reported in the literature. Two hundred angina and 52 AMI patients who had undergone the SECP treatment constitute the basis of this report. The present work represents an analysis of 6 yrs experience with studies on the design, development and clinical evaluation of the SECP method. Ninety-seven percent of the angina patients obtained long-term symptomatic relief. Relapse was minimal. In 95.7% of the AMI patients chest pain or shock symptoms were rapidly relieved. SECP with high DA appears to be very effective in improving myocardial blood supply and ventricular function. Moreover, the simplicity and advantages of this noninvasive sequenced counterpulsation method have been reported (1063 cases) from 31 clinics in China. This method is convenient, safe, and far more effective than conventional drug therapy for patients with acute and chronic ischemic myocardial disease.

Angina Pectoris↗
PubMedDate not supplied

Effects of the garlic compounds diallyl sulphide and diallyl disulphide on arylamine N-acetyltransferase activity in Klebsiella pneumoniae.

Arylamine N-acetyltransferase (NAT) activities with 2-aminofluorene (2-AF) were determined in the bacterium Klebsiella pneumoniae. Cytosols or suspensions of K. pneumoniae with or without specific concentrations of diallyl sulphide (DAS) or diallyl disulphide (DADS) as co-treatment showed different percentages of 2-AF acetylation. The data indicated that there was decreased NAT activity associated with increased levels of DAS or DADS in K. pneumoniae. In growth studies on K. pneumoniae it was demonstrated that DAS or DADS elicited a dose-dependent bacteriocide effect on K. pneumoniae. For the cytosol examinations, the apparent values of Km and Vmax were 0.96+/-0.09 mM and 7.87+/-0.79 nmol min(-1) mg(-1) protein, respectively, for 2-AF. However, when DAS or DADS was added to the reaction mixtures, the apparent values of Km and Vmax were 0.16+/-0.04 mM and 0.99+/-0.16 nmol min(-1) mg(-1) protein with DAS, respectively, and 0.14+/-0.18 mM and 0.85+/-0.10 nmol min(-1) mg(-1) protein with DADS, respectively, for 2-AF. For the intact bacteria examination, the apparent values of Km and Vmax were 0.57+/-0.06 mM and 2.00+/-0.14 nmol min(-1) per 10x10(10) CFU, respectively, for 2-AF. However, when DAS or DADS was added to the reaction mixtures, the apparent of values of Km and Vmax were 0.41+/-0.04 mM and 1.30+/-0.10 nmol min(-1) per 10x10(10) CFU with DAS, respectively, and 0.34+/-0.04 mM and 1.08+/-0.08 nmol min(-1) per 10x10(10) CFU with DADS, respectively, for 2-AF. This report is the first demonstration to show that the garlic components DAS and DADS would affect K. pneumoniae growth and NAT activity.

2-Acetylaminofluorene↗
PubMedDate not supplied

Microheterophase structure, permeability, and biocompatibility of A-B-A triblock copolymer membranes composed of poly(gamma-ethyl L-glutamate) as the A component and polybutadiene as the B component.

A-B-A block copolymers (EBE) consisting of poly(gamma-ethyl L-glutamate) as the A component and polybutadiene as the B component were synthesized. The microheterophase structure of these block copolymers, as observed microscopically, was less distinct than that of the block copolymer (GBG) composed of poly(gamma-benzyl L-glutamate) as the A component. This was attributed to the better compatibility of the ethyl group with polybutadiene block, compared with the benzyl group. The observed micelle size of various microheterophase structures ranged from 350 to 480 A, which agreed well with the micelle size estimated from a thermodynamic study. From the measurement of water permeation through the EBE block copolymer membranes, the contributions of the interfacial region between the alpha-helical polypeptide domain and polybutadiene domain to the permeability coefficient were concluded to be higher than those of poly(gamma-methyl L-glutamate)-polybutadiene block copolymer (MBM) membranes, i.e., more hydrophilic domain seemed to exist in EBE membranes than in MBM membranes. The results of in vivo tests on the tissue compatibility indicate that the EBE block copolymer membranes have good biocompatibility.

Animals↗
PubMedDate not supplied

Effects of the garlic components diallyl sulfide and diallyl disulfide on arylamine N-acetyltransferase activity in human colon tumour cells.

Diallyl sulfide (DAS) and diallyl disulfide (DADS), major components of garlic, were used to determine inhibition of arylamine N-acetyltransferase (NAT) activity in a human colon tumour (adenocarcinoma) cell line. Two assay systems were performed, one with cellular cytosols (9000g supernatant), the other with intact bacterial cell suspensions. The NAT activity in a human colon tumour cell line was inhibited by DAS and DADS in a dose-dependent manner in both system: that is, the greater the concentration of DAS and DADS in the reaction, the greater the inhibition of NAT activities in both systems. The data also indicated that DAS and DADS decrease the apparent values of Km and Vmax of NAT enzymes from human colon tumour cells in both systems examined. This is the first report to demonstrate that garlic components do affect human colon tumour cell NAT activity.

2-Acetylaminofluorene↗
PubMedDate not supplied

Effects of the butylated hydroxyanisole and butylated hydroxytoluene on the DNA adduct formation and arylamines N-acetyltransferase activity in human colon tumor cells.

The effects of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on N-acetyltransferase (NAT) activity were examined using a human colon tumor cell line (colo 205). BHA or BHT were added to the cytosols or to the medium of human colon tumor cells: The NAT activity was measured by high performance liquid chromatography, assaying the amounts of acetylated 2-aminoflluorene (AAF), p aminobenzoic acid (N-Ac-PABA), nonacetylated 2 aminofluorene (AF) and p-aminobenzoic acid (PABA). The NAT activity in the human colon tumor cells and cytosols was suppressed by BHA or BHT in a dose-dependent manner. The apparent values of Km and Vmax of NAT of human colon tumor cells were also decreased by BHA or BHT in cytosols and in intact cells. BHA or BHT may act as a noncompetitive inhibitor. After the incubation of human colon tumor cells with AF in the presence of BHA or BHT, the cells were recovered and DNA was prepared and hydrolysed to nucleotides. Adducted nucleotides were extracted into butanol and AF-DNA adducts were analysed by HPLC. The results also demonstrated that when BHA or BHT was added to the media, a decrease in AF-DNA adduct formation was seen in the human colon tumor cells. The finding of AF-DNA adduct formation in cultured human colon tumor cells suggest the possibility of using cultured cells for assessing arylamine-induced DNA damage.

2-Acetylaminofluorene↗