Biomedical subjects

D C Wang

Publications and source records attributed to D C Wang.

At least 73 records · Page 4Linked to original sources

PubMed1992

[A clinical and follow-up study in 33 cases of rapid cyclic affective psychosis].

Three hundred and fifty one cases of manic-depressive psychosis in our hospital were reviewed. Of these, 33 cases were rapid cyclothymic type (9.4%). Their clinical features, including sex, age, personality characteristics, phenomena and clinical types were analysed. The results suggested that: the major precipitating factors are psychosocial factors and antidepressants; the better therapy is the administration of the lithium combined with carbamazepine or neuroleptics; and more ideal prognosis occurs in any patient persisting in receiving the therapy.

Adolescent↗

PubMed1992

Follow-up of a modified catheter ablation of the atrioventricular junction in patients with atrial tachyarrhythmias.

In order to reduce cumulative energy, minimize barotrauma and infranodal injury, a modified catheter ablation technique was performed on seventeen patients. These patients had drug refractory atrial tachyarrhythmias (AT) consisting of thirteen with paroxysmal atrial fibrillation (PAf), three with sick sinus syndrome (SSS) with PAf, and one having SSS with rapid left atrial tachycardia. This technique, using the femoral approach, consisted of delivering a direct-current (DC) shock using a dual electrode configuration, to the ablation site adjacent the atrioventricular (AV) junction just before the disappearance of His deflection on the His bundle electrogram. After delivering 1-4 DV shock (mean 2.8) (cumulative energy 556 +/- 260 joules), 9 pts had first degree AV block (1st AVB) and 8 pts had complete AV block (CAVB). Only two pts had a right bundle branch block after ablation. During the clinical follow-up (15.4 +/- 2.7 months), sixteen pts were asymptomatic and were free of antiarrhythmic drugs. One pt was asymptomatic with quinidine which was ineffective before ablation. Pacemaker implantation was performed in 10 pts as a back-up for symptomatic SSS and CAVB. The results show this modified technique is relatively safe and effective.

Adult↗

PubMed1992

The characteristics and motion model of insulin monomer.

The extensive conformational comparisons among the determined structures of the different species and crystal forms of insulin and the varied insulin derivatives were performed by using the least-squares superimposition technique and the graphics technique. The results of the investigation showed that the structure of molecule I in 2Zn insulin was closer to that of the natural monomer; the conformational difference between two molecules of a dimer came out during dimerization and it was further improved and stabilized during the hexamerization and packing of hexamers in crystal; through the hinge peptides, such as A10, B4, B8, B24, B20 and B23, there was a flexible relative motion among the structural segments in the insulin molecule, and the residues at the B-chain C-terminal might have a shift of more than 10A; the mobility for each residue side-chain was very different due to the different surroundings.

Insulin↗

PubMed1991

The iron-sulfur clusters in the two related forms of mitochondrial NADH: ubiquinone oxidoreductase made by Neurospora crassa.

Two related forms of the respiratory-chain complex, NADH: ubiquinone oxidoreductase (Complex I) are synthesized in the mitochondria of Neurospora crassa. Normally growing cells make a large, piericidin-A-sensitive form, which consists of some 23 different nuclear- and 6-7 mitochondrially encoded subunits. Cells grown in the presence of chloramphenicol make a small, piericidin-A-insensitive form which consists of only approximately 13 nuclear-encoded subunits. The subunits of the small form are either identical or similar to nuclear-encoded subunits of the large form. The iron-sulfur clusters in these two forms of Complex I are characterized by redox potentiometry and EPR spectroscopy. The large form of Complex I contains four EPR-detectable iron-sulfur clusters, N1, N2, N3 and N4, with the spin concentration of the individual clusters equivalent to the flavin concentration, similar to the mammalian counterparts. The small Complex I contains clusters N1, N3 and N4, but it is devoid of cluster N2. A model of the electron-transfer route through the large form of Complex I has been derived from these findings and an evolutionary pathway which leads to the emergence of large Complex I is discussed.

Animals↗

PubMed1990

Studies on the NADH-menaquinone oxidoreductase segment of the respiratory chain in Thermus thermophilus HB-8.

Five distinct low potential iron-sulfur clusters have been identified potentiometrically in the membrane particles from Thermus thermophilus HB-8. Three of these clusters (designated as [N-1H]T, [N-2H]T, and [N-3]T) exhibit the following midpoint redox potentials and g values (Em8.0 = -274 mV, gx,y,z = 1.93, 1.94, 2.02), (Em8.0 = -304 mV, gx,y,z = 1.89, 1.95, 2.04), and (Em8.0 = -289 mV, gx,y,z = 1.80, 1.83, 2.06), respectively. These clusters, one binuclear and two tetranuclear, have been shown to be components of the energy coupled NADH-menaquinone oxidoreductase complex (NADH dh I). They are reducible by NADH in the piericidin A-inhibited aerobic membrane particles as well as in the purified NADH dh I complex. Two additional very low potential iron-sulfur clusters (one binuclear, [N-1L]T, and one tetranuclear, [N-2L]T) were observed in membrane particles. These clusters possess the following physiochemical properties (Em8.0 = -418 mV, gx,y,z = 1.93, 19.5, 2.02) and (Em8.0 = -437 mV, gx,y,z = 1.89, 1.95, 2.04), respectively. No high potential tetranuclear cluster equivalent to the mitochondrial iron-sulfur cluster [N-2]B was found in this bacterial system. In membrane particles isolated from T. thermophilus HB-8 cells, four different semiquinone species have been identified based on their redox midpoint potentials [Em9(Q/QH2) = 40, -100, -160, -300 mV] and sensitivity to the quinone analogue inhibitor, 2-heptyl-4-hydroxy quinoline-N-oxide. Of these semiquinone species the -100 mV component has been suggested to be part of the NADH dehydrogenase. Piericidin A sensitive delta psi formation has been demonstrated to be coupled to the NADH-MQ1 oxidoreductase in membrane vesicles of T. thermophilus HB-8.

Cell Membrane↗

PubMed1990

Detection of human cytomegalovirus in cervicovaginal cells by culture, in situ DNA hybridization and DNA amplification methods.

The presence of human cytomegalovirus (HCMV) was tested in 388 cervicovaginal cells specimens obtained from the same number of pregnant women. HCMV was detected in 5.41%, 11.6% and 13.9% of these specimens by conventional culture, in situ DNA hybridization and polymerase chain reaction (PCR) methods, respectively. The sensitivities of detecting HCMV by in situ hybridization and PCR methods were 76.2% and 90.5% and the specificities were 92.1% and 90.5%, respectively, when compared with conventional culture method. The PCR compared favourably with both conventional culture and in situ hybridization methods and it may become a valuable and useful tool for the early and rapid detection of HCMV in clinical specimens.

Base Sequence↗

PubMed1989

High resolution 1H-NMR studies of Des-(B26-B30)-insulin; assignment of resonances and properties of aromatic residues.

The assignments of 1H resonances of the eight aromatic residues of Des-(B26-B30)-insulin are reported, based on pH titration, selective spin decoupling and its 500 MHz 1H two-dimensional (2D)-COSY spectrum. The pK values of the three tyrosines A14, A19 and B16 are 10.84, 11.27 and 10.40, respectively. Tyrosine A19 is buried in a hydrophobic environment, while Tyrosine B16 is exposed in a relatively hydrophilic state. Among the three phenylalanines, the ring proton resonances of Phe-B25 undergo abnormal upfield shifts, probably due to the ring currents of the nearby Phe-B24 and Tyr-B16. From this study of the low-field region of 1H-NMR spectrum of Des-(B26-B30)-insulin, we conclude that this molecule probably maintains the major structural features of insulin in aqueous solution, but there are some readjustments of the peptide conformation.

Amino Acid Sequence↗

PubMed1989

[Influence of Astragalus membranaceus (AM) polysaccharide FB on immunologic function of human periphery blood lymphocyte].

Chemotherapy and/or radiotherapy are believed to further lower the already low cellular immunologic response of cancer patients giving poorer prognosis. A number of Chinese medicinal herbs known as Fuzheng therapy (FZT), in which AM is an active one, are being used to enhance the natural host defence function in cancer patients. Among some fractions of AM polysaccharide extracts, FB was the strongest. In vitro restorative effects of FB in 18 normal healthy individuals and in 9 previously untreated advanced cancer patients are reported. Local graft versus host (GVH) reaction and blastogenic response of lymphocytes in vitro (BRL) were used as test index for T-cell function. GVH reaction nodules with a volume greater than or equal to 50 mm3 were considered as positive GVH reaction. FB 100 micrograms/ml induced a restored reaction in 18 normal donors with an increase in local GVH reaction from 69.6 +/- 20.8 mm3 to 148.9 +/- 40.8 mm3 (P less than 0.001) and in 9 cancer patients with an increase in local GVH reaction from 29.3 +/- 9.5 mm3 to 137.2 +/- 35.8 mm3 (P less than 0.001). The local GVH reaction of the 9 cancer patients went from negative to positive. FB on BRL was detected. 10 micrograms/ml of FB augmented the spontaneous 3H-TdR incorporation in the lymphocyte of 18 normal subjects from 310.2 to 910.9 counts per minute (cpm) and of 9 patients from 248.5 to 642.2 cpm, but the effects were not strong. The effect of single mitogen was not remarkable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Crystal structure determination of desheptapeptide (B24--B30)-insulin.

Desheptapeptide (B24--B30)-insulin (DHPI), an essentially inactive insulin analog, is crystallized in space group P212121 with two molecules in an asymmetric unit. The orientations of the molecules in the crystal cell have been determined by using Patterson search method at 6 A resolution and the positions of the molecules are deduced from translation function calculation and R search at 3 A resolution. After using the rigid body refinement (CORELS) further to refine the orientational and positional parameters as well as the initial energy restrained refinement (EREF) for the model, the crystallographic R value is reduced to 0.384 at 3 A resolution. The initial Fourier map shows that the B-chain N-terminal (B1-B8) and C-terminal (B20-B22) segments, compared with the native 2 zinc insulin, exhibit drastic conformational changes, but the three helices of B- and A-chains and their relative arrangement are essentially kept in DHPI.

Crystallography↗

PubMed1989

Crystal structure determination of 4-zinc bovine insulin at 1.9 A resolution.

With the isomorphous difference Fourier method and the restrained least-squares refinement technique, the crystal structure of 4-zinc bovine insulin in space group R3 was determined. The final crystallographic residual is 0.19 at 1.9 A resolution. Based on the refined model, the structural mechanism for prolonged action of 4-zinc insulin is discussed.

Animals↗

PubMed1988

Long-term survival of 1035 cases of nasopharyngeal carcinoma.

Long-term results of 1035 previously untreated patients with nasopharyngeal carcinoma seen at Cancer Hospital, Chinese Academy of Medical Sciences, between March 14, 1958 and March 15, 1968 are presented. Of the 1035 patients, 715 were treated with radiation therapy; 281 patients did not receive radiation therapy; and 39 patients whose records were lost. The patients were further subdivided according to the dose of radiation therapy (greater than 4000 rad versus less than 4000 rad), the presence or absence of pathologic confirmation of diagnosis, whether or not follow-up was complete, and whether or not distant metastases developed during treatment. All patients are included in the analysis. The 5-year and 10-year absolute survival rates for the entire group of 1035 patients are 19.6% and 14.5%, respectively. The 5-year and 10-year relative survival rates for the 715 patients who received radiation therapy are 28.4% and 21.0%, respectively. The 5-year and 10-year relative survival rates of the 464 with a pathologically confirmed diagnosis, who were without evidence of distant metastases and who received at least 4000 rad were 34.7% and 25.4%, respectively. Details regarding our statistical methods as well as an exact breakdown of the patient population are presented.

Carcinoma↗

PubMed1988

Combined effects of UFT with other anticancer agents using in vivo chemosensitivity tests.

In order to estimate the combined effects of UFT with other anticancer agents, a nude mouse experimental system (NMES), and a subrenal capsule assay (SRCA) were investigated. Three human tumor xenografts were serially transplanted into nude mice and examined. These were; EH-1 established from esophageal cancer, SH-6 from gastric cancer and CH-3 from colon cancer. The antiproliferative effects were estimated in accordance with the NCI therapeutic protocol. Significant antiproliferative effects were obtained only in NMES and a positive relationship was observed between the two assays (p less than 0.05). In the groups which were treated with a single agent, positive tumor responses were observed against mitomycin C in SH-6, against cis-DD platinum in SH-6 and EH-1, and against adriamycin in EH-1, respectively. On this study the synergistic, additive and subadditive effects were defined as the positive combined effects. The combination of MMC and UFT produced positive combined effects for all xenografts in both assays.

Animals↗

PubMed1988

[Radiation treatment of metastatic tumor in the brain].

Sixty-seven patients with metastatic tumor in the brain were seen from 1975 to Oct. 1985. 11 of the 22 untreated patients were followed to their death, the median survival was 2.9 months. The other 45 patients were all treated by irradiation. 40(89%) patients had bronchogenic carcinoma, three had primaries in other parts of the body and two had unknown primaries. In 16 patients, whole brain was irradiated to a dose of 1000-4000 cGy. Their 6 month survival rate was 25% but all died within one year. In 24 patients, whole brain was first irradiated to 3000-4000 cGy. Then the dose was increased to 5000-6000 cGy by cone down technique. Their 6 month survival was 75%, 1 year survival 33%. The high-dose-cone down method is obviously more effective. In the other 5 patients who were retreated locally for recurrence or new foci in the other parts of the brain, their survival was 4 to 8 months taken from the start of the second course of radiotherapy. One of these five patients is still living as of this writing. Extensive brain necrosis was observed in three patients who received whole brain radiation in the second course. Yet untoward reactions were noted in the two patients who received local irradiation in the second course. This may imply that, for the second course, only local radiation is indicated.

Brain Neoplasms↗

PubMed1987

[In vivo chemosensitivity test for UFT and FT-207. II. Chemosensitivity test on human tumor xenografts transplanted in nude mice].

The present study was designed to predict the clinical effect of UFT and FT-207 in short-term administration using a nude mouse-xenograft system. Five human tumor xenografts transplanted into nude mice were used. UFT and FT-207 were administered with the LD10 doses orally for seven consecutive days. Tumor size was measured on day 7, 14 and 21 after the administrations. No significant differences in antiproliferative effects were observed between the measurements of tumor size made on day 7 and day 21. UFT inhibited significantly the tumor growth of CH-I established from colon cancer in which the prolongation of life span has been obtained by clinical long-term administration of UFT. These results suggest that this chemosensitivity test system using nude mice is useful for prediction of clinical response at 7 days after final administration of UFT and FT-207.

Adenocarcinoma↗

PubMed1986