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Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 991 records · Page 55Linked to original sources
PubMed1989

Enhancement of human monocyte function against Candida albicans by the colony-stimulating factors (CSF): IL-3, granulocyte-macrophage-CSF, and macrophage-CSF.

The effect of IL-3, granulocyte-macrophage (GM)-CSF and macrophage (M)-CSF on Candida albicans growth inhibition by human peripheral blood monocytes was investigated. By using a radiolabel microassay developed in our laboratory that makes use of the incorporation of [3H]glucose into residual C. albicans, we demonstrated that rGM-CSF and rIL-3 effectively enhanced human monocyte-mediated anticandidal activity. Incubation for 24 h with either GM-CSF or IL-3 significantly enhanced monocyte antifungal responses down to 0.01 U/ml. M-CSF, at higher concentrations of 10 U/ml, could also enhance monocyte function but to a smaller degree. None of the CSF interfered directly with fungal growth, even up to 1000 U/ml. Because IFN-gamma is also a known monocyte activator, its effect on monocytes was also assessed. Monocytes were first cultured in medium for several days and then further incubated with each of the cytokines. Monocytes aged in medium were found to lose their spontaneous anticandidal activity. Such aged monocytes did not develop anticandidal activity in response to IFN-gamma but did in response to GM-CSF or IL-3. To further elucidate this difference, fresh monocytes were continuously cultured with or without cytokines for 1 to 5 days before assessing their anticandidal activity. Monocytes cultured in IFN-gamma progressively lost their activity by 2 days but monocytes in GM-CSF or IL-3 maintained their high level of anticandidal activity throughout the whole length of culture. Therefore, GM-CSF and IL-3 not only enhanced fresh monocyte anticandidal activity, but maintained monocyte function for a longer period. These results suggest that GM-CSF and IL-3 may act on monocytes via a different pathway than does IFN-gamma.

Candida albicans↗
PubMed1989

A "screened" electrostatic ion trap for enhanced mass resolution, mass accuracy, reproducibility, and upper mass limit in Fourier transform ion cyclotron resonance mass spectrometry.

Until now, it was thought that the optimal static electromagnetic ion trap for Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry should be designed to produce a quadrupolar electrical potential, for which the ion cyclotron frequency is independent of the ion's preexcitation location within the trap. However, a quadrupolar potential results in a transverse (to the magnetic field) electric field that increases linearly with distance from the center of the trap. That radially linear electric field shifts the observed ICR frequency, increases the ICR orbital radius, and ultimately limits the highest mass-to-charge ratio ion that can be contained within the trap. In this paper, we propose a new static electromagnetic ion "trap" in which grounded screens placed just inside the usual "trapping" plates produce a good approximation to a "particle-in-a-box" potential (rather than the quadrupolar "harmonic oscillator" potential). SIMION calculations confirm that the electric potential of the screened trap is near zero almost everywhere within the trap. For our screened orthorhombic (2.5 in. X 2 in. X 2 in.) trap, the experimental ICR frequency shift due to trapping voltage is reduced by a factor of approximately 100, and the experimental variation of ICR frequency with ICR radius is reduced by a factor of approximately 10 compared to a conventional (unscreened) 2-in. cubic ion trap.(ABSTRACT TRUNCATED AT 250 WORDS)

Electricity↗
PubMed1989

Curative radiotherapy of early operable non-small cell lung cancer.

The results of 44 patients with early operable non-small cell lung cancer treated from January 1975 through 1981 are retrospectively analysed. All were proven by pathology and/or cytology and denied surgery in our joint Chest Clinic for various reasons. 55-70 Gy/6-7 weeks was delivered by conventional fractionation through A-P portals by telecobalt and/or 25-35 MeV high energy electron beam or 8 MV X-ray. 40 Gy/4 weeks was given prophylactically to the mediastinum. The 1-, 3-, and 5-year survival rates, 93, 55, and 32%, are superior to what is reported in the literature. In the present series, the favorable factors are: (1) patients without any intercurrent disease but refused operation; (2) T1 lesions; (3) complete regression of the lesion at the conclusion of radiotherapy; (4) doses ranging from 69 to 70 Gy. It is shown that early non-small cell lung cancer can be cured by radiotherapy alone giving survival rates comparable to surgery. Prospective randomized clinical trials are warranted.

Adult↗
PubMed1989

Nutritional status of institutionalized children and adolescents with developmental disabilities.

The relationship was explored between anomalies associated with developmental disabilities and nutritional status of institutionalized children and adolescents who received comprehensive interdisciplinary services. Variables included dietary intake, serum laboratory values, anthropometric measurements, feeding skills assessment, and clinical assessment. Mean intakes of nutrients were greater than 67% of Recommended Daily Allowances. Laboratory values were within normal ranges with the exceptions of serum ferritin, which was borderline or below normal in 46% of the males and 55% of the females, and alkaline phosphatase, which was elevated in 70% of residents receiving anticonvulsants. Energy intake was highest in residents with adequate feeding skills, followed by nonfeeders and feeders requiring behavior management. Subjects had greater triceps skinfold and lower mid-arm muscle circumference and weight measurements as compared to reference data. Findings of this study suggest that these developmentally disabled children and adolescents who received comprehensive interdisciplinary nutritional services, in general, are adequately nourished and have nutrient intakes that meet the RDA requirements.

Activities of Daily Living↗
PubMed1989

A re-examination of the crystal structure of A-DNA using fiber diffraction data.

Classical A-DNA helices with h = 0.25 nm may represent the greatest mass per unit length attainable by polynucleotide duplexes. The X-ray diffraction pattern from polycrystalline and well-oriented fibers of calf thymus DNA in its A-form has been carefully re-examined. Indexing on the basis of a C-face-centered monoclinic unit cell of dimensions a = 2.170 nm, b = 3.990 nm, c = 2.803 nm and beta = 96.82 degrees is superior to alternatives that have been proposed. Two right-handed. Watson-Crick base-paired, helical DNA chains with 2 X 11 nucleotides per 2.803 nm pitch, each carrying C3'-endo furanose rings, pass through the unit cell. The crystallography requires the two chains in the duplex to be antiparallel and conformationally identical but the 11 nucleotides in each pitch may be distinct. However, a secondary structure with a mononucleotide asymmetric unit provides as good an X-ray agreement as one with 11 distinct nucleotides. This relative lack of variability is quite different from what is observed in fibrous B-DNAs.

Animals↗
PubMed1989

DL and D sotalol decrease defibrillation energy requirements.

We examined the acute effects of intravenous DL and D sotalol on the energy requirements for internal defibrillation (DF) in 44 dogs anesthetized with pentobarbital (n = 18), enflurane (n = 8), and fentanyl (n = 18). Multiple shocks of varying energies were applied through left and right ventricular epicardial patch electrodes to relate delivered energy to percent success in DF. The energies required for 50% success in DF (E) were estimated by logistic regression. DL or D sotalol was administered in a loading (4 mg/kg over 10 min) and maintenance (1.5 mg/kg/hr) infusion and the energy--success curve was again measured 30 minutes after drug administration. The effect of DL and D sotalol on E50 was compared to controls given saline. Both DL and D sotalol significantly lowered E50 by 16% +/- 14% (P less than 0.05) and 24.5% +/- 8.2% (P less than 0.05), respectively, in fentanyl anesthetized animals; this was accompanied by a 22% +/- 8% (P less than 0.05) and 16% +/- 5% (P less than 0.01) increase in ventricular effective refractory period (VERP), respectively. In pentobarbital anesthetized dogs, DL and D sotalol decreased E50 by 16% +/- 27% (P = ns) and 11% +/- 16% (P less than 0.05), respectively, and were associated with a 23% +/- 5% (P less than 0.01) and 12 +/- 4% (P less than 0.05) prolongation of VERP. DL and D sotalol decrease defibrillation energy requirements, possibly as a result of their Class III antiarrhythmic drug action.

Animals↗
PubMed1989

Epithelial modulation of trachealis muscle tension is calcium and temperature dependent.

The tracheobronchial epithelium produces inhibitory substance(s) that alter the tracheal smooth muscle tension. This study examined the effect of changes in extracellular Ca2+ and temperature in vitro on the tension response of rabbit trachealis muscle to mechanical removal of the epithelium. Tension during acetylcholine- and KCl-induced contractions was examined at 0, 0.75, 1.5, 2.5, and 5 mM bath Ca2+ concentrations and at 37, 30, 23, and 41 degrees C bath temperature. At most extracellular Ca2+ concentrations (i.e., 0.75, 1.5, 2.5, and 5 mM), epithelial removal shifted the acetylcholine concentration response approximately one-half log to the left (P less than 0.001 for each condition) but had no effect on the responses to KCl (P = NS). Reductions in bath Ca2+ to 0 mM eliminated the epithelial inhibitory effect on the acetylcholine response. In contrast to the effects of reductions in Ca2+, cooling the airway to 30 and 23 degrees C progressively diminished the magnitude of the epithelial inhibitory effect. Our results indicate that the influence of the tracheal epithelium on tracheal smooth muscle responses to constrictor agonists is substance specific and can be diminished by reductions in tracheal temperature and extracellular Ca2+ concentration.

Acetylcholine↗
PubMed1989

[A morphological study of the retinal vessels in experimental diabetic rats].

The retinal vascular network of experimental diabetic rats was studied by trypsin digestion 6 months after an elevation in blood sugar level to 400-600 mg/dl, when the retinal capillaries began to show pericyte loss, with appearance of capillary microaneurysms, acellular capillaries, venular obstruction, capillary varicosis and diametral irregularity. The possible mechanism of these changes were discussed.

Alloxan↗
PubMed1989

[Histochemical studies on some enzymes in Clonorchis sinensis].

The localization of some enzyme in adult worms of Clonorchis sinensis was studied by histochemical method in this paper. Acid phosphatase was detected mainly in digestive duct, subtegument and the walls of testis, uterus and ovary; acetylcholinesterase was found in oral sucker, ventral sucker, pharynx; and ATPase was found to exist in oral sucker, ventral sucker, pharynx and muscle layer in the subtegument. The eggs of C. sinensis possessed the above three enzymes.

Acetylcholinesterase↗
PubMed1989

[Clinical effects and experimental study on gossypol in endometriosis].

Effects of the gossypol on endometriosis in 12 cases of control were observed. The results showed that the gossypol administered orally was effective in endometriosis patients. The basal body temperature changed from biophase to monophase. Dysmenorrhea disappeared in 11/12 patients. Amenorrhea occurred in 10/12 patients and the ovarian endometrial cyst was shrinkable. Serum progesterone and estradiol were decreased after gossypol administration, but follicle-stimulating hormone and luteinizing hormone were increased evidently. Histochemical and cytochemical observations revealed that the activity of acid phosphate (ACP), nonspecific esterase (NSE) and alkaline phosphate (AKP) in both aberrant uterine endometrium and uterine endometrium in situ were decreased evidently. The above results suggest that the satisfactory therapeutic effect of gossypol on endometriosis may be due to not only the indirect but also the direct action on uterine endometrium.

Adult↗
PubMed1989

Randomized clinical trial on the combination of preoperative irradiation and surgery in the treatment of esophageal carcinoma: report on 206 patients.

From June 1977 to May 1985, a prospective randomized clinical trial on pre-operative radiation for esophageal carcinoma was carried out in 206 patients. Lesions under 8 cm in length and patients younger than 65 years, at least on semi-liquid diet and not contra-indicated for surgery were randomized into a combined group (104 patients) or a surgery alone group (102 patients). Eight MV X ray units were used for the pre-operative radiation using A-P portals to deliver 4,000 cGy to the whole mediastinum and the left gastroepiploic lymphatic chain. Surgery was carried out after 2 to 4 week's rest. The immediate results of the combined group and the surgery alone group were: resection rate 93% and 85%, operative mortality 5% and 6%, intra-thoracic anastomotic leak 0% and 1%, positive pathology at the esophageal stump 0% and 2%, and lymph nodes metastasis 27% and 35% respectively. The 5-year survival rates of the combined group and the surgery alone group were 35% and 30%. We have noticed that those patients with lesions showing radiation reaction of grade III gave a 5-year survival of 50% (12/24). Because intra- and extra-thoracic lymphnode metastasis caused failures (41% and 34% of these two groups), increasing the preoperative tumor dose to 60 Gy or designing post-operative irradiation to cover the bilateral supraclavicular areas was necessary. The whole mediastinum and the left gastroepiploic lymphatics could further improve the results of surgery. Further studies are needed.

Adult↗
PubMed1989

[Whole nucleotide sequence of penicillin G acylase gene and its flanking region from E. coli].

Some of microorganisms have been known to possess penicillin G acylase activity. The E. coli derived penicillin G acylase (PGA) can catalyze the conversion of penicillin G into phenylacetic acid and 6-amino-penicillanic acid, the latter is used as the starting compound for the industrial formation of semi-synthetic penicillins. Apart from its industrial importance, the enzyme PGA displays a number of interesting properties. Catalytically active enzyme is localized in the periplasmic space of E. coli cells and composed of two dissimilar subunits. The two subunits are apparently produced from a precursor protein, via a processing pathway hitherto unique in its features for a prokaryotic enzyme. The studies on processing of the precursor and on the relationship between structure and function of the mature enzyme are important theoretically. Previously we cloned a 3.5 kb DNA fragment from a strain (E. coli AS 1.76), which displays PGA activity. In this paper, we report a nucleotide sequence of the 3.5 kb DNA fragment containing PGA gene. After insertion of the DNA fragment into EcoR I and Hind III sites in pWR 13, pPGA 20 had been obtained. We subcloned the Hind III and Bg1 II treated fragment of 1.6 kb in length from pPGA 20 into Hind III and BamH I sites of pWR 13 to get a pPGA 1.6, and Bg1 II and EcoR I treated fragment of 1.9 kb in length into BamH I and EcoR I sites of pWR 13 to get a pPGA 1.9. The linearized pPGA 1.9 which were digested with appropriate restriction enzymes were progressively shortened from both ends respectively by digestion with Bal 31 nuclease, followed by cleavage of shortened target DNA off vector DNA molecules with appropriate restriction enzymes. The series of the DNA fragments shortened from EcoR I end were then cloned into plasmid pWR 13 which had previously digested with Hind III and Sma I enzymes (Fig. 1). The DNA fragment cloned in pWR 13 were directly sequenced on the resulted plasmids by using primer I and primer II. Thus we have obtained the complete nucleotide sequence of the 3.5 kb DNA fragment. The 3.5 kb fragment contains an intact PGA gene which is 2.6 kb.(ABSTRACT TRUNCATED AT 400 WORDS)

Amidohydrolases↗
PubMed1988

Blocking of collagenase secretion by estramustine during in vitro tumor cell invasion.

The effects of the antitumorigenic drug estramustine on tumor cell membrane penetration (invasion) were investigated in vitro by utilizing a synthetic basement membrane system (a modified Boyden chamber). Tumor cells were plated on a "partition barrier," consisting of a porous filter (8-micron pores) which was coated with a reconstituted basement membrane matrix (Matrigel), and induced to migrate across the barrier with conditioned medium obtained from 9DU 145 human prostatic tumor cells (passage 9). Quantitative radiolabeling studies demonstrated that specially isolated lines (isolated by several passages through the Matrigel) of DU 145 cells, A2058 melanoma, and B16-F10 melanoma cells were highly invasive such that 15 to 20% migrated across a 1-mm-thick Matrigel layer within 5 h at 37 degrees C. NIH-3T3 cells, mouse fibroblasts, and 20DU 145 cells (passage 20) exhibited little or no membrane invasive behavior. Micromolar concentrations of estramustine (30 to 120 microM) inhibited invasion by the invasive cell lines in a dosage-dependent fashion. Quantitative enzymatic assays and radioimmune assays demonstrated that estramustine inhibited membrane invasion by blocking type IV collagenase secretion. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blots confirmed that 30 to 60 microM estramustine blocked secretion of a Mr 105,000 collagenase protein. Indirect studies showed that a collagenase antibody raised against the Mr 105,000 protein and inhibitors of proteinase activity, including a metalloproteinase inhibitor, and 1,10-phenanthroline, blocked invasion. Because the antibodies inhibited type IV collagenase digestion of 3H-mouse type IV collagen, and invasion simultaneously, it is proposed that collagenolytic activity is involved in invasion. These data demonstrate that estramustine blocks proteinase secretion, and suggest that estramustine may be a useful therapeutic drug for the prevention of metastasis.

Cell Division↗
PubMed1988

Lithium respecifies cyclic AMP-induced cell-type specific gene expression in Dictyostelium.

We investigated the effect of LiCl on pattern formation and cAMP-regulated gene expression in Dictyostelium discoideum. In intact slugs, 5 mM LiCl induces an almost complete redifferentiation of prespore into prestalk cells. We found that LiCl acts by interfering with the transduction of extracellular cAMP to cell-type-specific gene expression; LiCl inhibits the induction of prespore-specific gene expression by cAMP, while it promotes the induction of prestalk-associated gene expression by cAMP. Our results indicate that two divergent pathways transduce the extracellular cAMP signal to, respectively, prestalk and prespore gene expression.

Chlorides↗
PubMed1988

Cell cycle phase in Dictyostelium discoideum is correlated with the expression of cyclic AMP production, detection, and degradation. Involvement of cyclic AMP signaling in cell sorting.

Cell cycle phase in Dictyostelium is correlated with a different preference for either spore or stalk differentiation. Cells which start development early in the cell cycle (E cells) exhibit a strong tendency to sort to the prestalk region of slugs, while late cell cycle cells (L cells) sort to the prespore region. We investigated the expression of the cAMP chemotactic system during development of synchronized E and L cells and found that E cells exhibit cAMP-binding activity, cell surface cAMP-phosphodiesterase (mPDE) activity, and the ability to relay cAMP signals at least 2 hr earlier and to higher levels than L cells. We hypothesize that E cells are prestalk sorters because they are the first to initiate aggregation centers and respond most effectively with chemotaxis and signal relay.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1988

Localization of chemoattractant receptors on Dictyostelium discoideum cells during aggregation and down-regulation.

cAMP chemoattractant receptors on the surface of Dictyostelium discoideum cells are visualized by means of immunocytochemistry. Receptor antigen is virtually absent from growing cells and begins to accumulate after about 6 hr of starvation, concomitant with the increase in surface cAMP binding activity. In aggregating cells, the antigen is uniformly distributed over the cell surface. Persistent cAMP stimulation, which leads to down-regulation of cAMP binding activity, induces a striking rearrangement of receptor antigen into patches or internal vesicles. A similar patching of receptor antigen is observed during tight aggregate formation, when surface cAMP binding activity decreases. These observations indicate that receptor down-regulation involves receptor agglomeration and suggest that receptor down-regulation takes place in vivo, when tight aggregates are being formed.

Cell Aggregation↗
PubMed1988

Estramustine binds a MAP-1-like protein to inhibit microtubule assembly in vitro and disrupt microtubule organization in DU 145 cells.

The twofold purpose of the study was (a) to determine if a MAP-1-like protein was expressed in human prostatic DU 145 cells and (b) to demonstrate whether a novel antimicrotubule drug, estramustine, binds the MAP-1-like protein to disrupt microtubules. SDS-PAGE and Western blots showed that a 330-kD protein was associated with microtubules isolated in an assembly buffer containing 10 microM taxol and 10 mM adenylylimidodiphosphate. After purification to homogeneity on an A5m agarose column, the 330-kD protein was found to promote 6 S tubulin assembly. Turbidimetric (A350), SDS-PAGE, and electron microscopic studies revealed that micromolar estramustine inhibited assembly promoted by the 330-kD protein. Similarly, estramustine inhibited binding of the 330-kD protein to 6-S microtubules independently stimulated to assemble with taxol. Immunofluorescent studies with beta-tubulin antibody (27B) and MAP-1 antibody (MI-AI) revealed that 60 microM estramustine (a) caused disassembly of MAP-1 microtubules in DU 145 cells and (b) removed MAP-1 from the surfaces of microtubules stabilized with 0.1 microM taxol. Taken together the data suggested that estramustine binds to a 330-kD MAP-1-like protein to disrupt microtubules in tumor cells.

Blotting, Western↗