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Biomedical subjects

C Yang

Publications and source records attributed to C Yang.

At least 487 records · Page 27Linked to original sources
PubMed1991

[Observation of curative effect of refined interferon-alpha on viral pneumonia in infants].

Fifteen cases of viral pneumonia in infants were treated with refined interferon-alpha and antibiotics. Clinical symptoms of the cases with IFN-alpha were relieved in 1.40-2.79 days, earlier than those of the control. Clinical recovery time was on the average shorter than that of the control by 1.9 days, and complete recovery by 1.5 days. The difference is statistically significant. It suggested that the clinical effect of IFN-alpha together with antibiotics is better than that of antibiotics alone. There was no significant change between the experimental and control groups in absolute lymphocyte count Ig and T-cell, but OKT3 increased and OKT8 decreased slightly. The study shows that IFN is an effective and safe administration for viral pneumonia.

Anti-Bacterial Agents↗
PubMed1990

[Effect of albendazole and pyrantel in treating intestinal helminthiasis and controlling the recurrence of hookworm infections].

A total of 720 human intestinal helminthic infections were divided into 4 groups and treated with albendazole 400mg/d x 3d, 400mg/d x 5d, pyrantel 1,500mg/d x 3d, or 1,500mg/d x 5d. Half a month after treatment, the negative rates of hookworm egg were 98.6, 98.6, 86.2 and 93.5%, those of ascaris egg were 96.5, 98.2, 92.9 and 96.3%, and those of whipworm egg were 86.4, 89.0, 68.9 and 67.0% respectively. Reduction rate of hookworm egg reached more than 98% in all the 4 groups. Six months after treatment, however, the positive rates of all the 4 groups rose again in varying degrees. The predominant species of hookworm infections was Necator americanus before the treatment and Ancylostoma duodenale after the treatment. It was demonstrated that the recurrence of hookworm infection resulted from A. duodenale infections, while a single dose of 400mg albendazole per day for 3 or 5 days showed good effect in controlling the recurrence of hookworm infections in a certain area.

Adolescent↗
PubMed1990

Calcitonin: chronotherapeutic effect on osteopenia in the ovariectomized rat.

This chronotherapeutic study has revealed no clear evidence to support the concept that calcitonin promotes bone formation in intact or OVX'd rats. Rather, the efficacy of CT-impaired bone resorption appeared to be optimal in OVX'd rats treated during the daytime, and least effective during the first half of the environmental dark span. These findings indicate a benefit for calcitonin chronotherapy in this animal model where the cellular kinetics resemble those documented in early development of postmenopausal osteoporosis.

Animals↗
PubMed1990

Gossypol-induced alterations of aminophospholipid composition in human sperm.

Gossypol-induced alterations of aminophospholipid composition in human sperm were observed and the effects of some factors on these alterations were investigated. The alterations of aminophospholipid composition of human sperm induced by gossypol included a progressive decrease in the levels of phosphatidylethanolamine (PE) and phosphatidylserine (PS) when gossypol concentrations ranged from 5-500 mumol/L, and a progressive increase in the level of (LPE) at lower gossypol concentrations (5-50 mumol/L). The conversion of PE into lysophosphatidylethanolamine (LPE) was strongly enhanced by Ca2+ and inhibited by 0.5 mmol/L EDTA, while PMSF, NEM, iodoacetamide and Zn2+ had no effect. This conversion was weaker in sperm with stripped surface proteins than in normal sperm. In addition, three surface proteins (MW 80, 60 and 40 kD) were fixed on the plasma membrane by gossypol treatment. The significance of gossypol action and the possibility that sperm PLA2, PE and some surface proteins might play an important role in the physiological acrosome reaction of human sperm, as well as in oocyte penetration, are discussed.

Gossypol↗
PubMed1989

Binding of pyrimidin-2-one ribonucleoside by cytidine deaminase as the transition-state analogue 3,4-dihydrouridine and the contribution of the 4-hydroxyl group to its binding affinity.

Cytidine deaminase, purified to homogeneity from constitutive mutants of Escherichia coli, was found to bind the competitive inhibitors pyrimidin-2-one ribonucleoside (apparent Ki = 3.6 x 10(-7) M) and 5-fluoropyrimidin-2-one ribonucleoside (apparent Ki = 3.5 x 10(-8) M). Enzyme binding resulted in a change of the lambda max of pyrimidin-2-one ribonucleoside from 303 nm for the free species to 239 nm for the bound species. The value for the bound species was identical with that of an oxygen adduct formed by combination of hydroxide ion with 1,3-dimethyl-2-oxopyrimidinium (239 nm), but lower than that of a sulfur adduct formed by combination of the thiolate anion of N-acetylcysteamine with 1,3-dimethyl-2-oxopyrimidinium (259 nm). The results suggest that pyrimidin-2-one ribonucleoside is bound by cytidine deaminase as an oxygen adduct, probably the covalent hydrate 3,4-dihydrouridine, rather than intact or as an adduct involving a thiol group of the enzyme. In dilute solution at 25 degrees C, the equilibrium constant for formation of a single diastereomer of 3,4-dihydrouridine from pyrimidin-2-one ribonucleoside was estimated as approximately 4.7 x 10(-6), from equilibria of dissociation of water, protonation of 1-methylpyrimidin-2-one, and combination of the 1,3-dimethylpyrimidinium cation with the hydroxide ion.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytidine↗
PubMed1989

The influence of antithyroid drugs and iodine on thyroid cell MHC class II antigen expression.

We have investigated the influence of antithyroid drugs (methimazole and propylthiouracil) and sodium iodide on the expression of major histocompatibility (MHC) class II antigen expression in human and rat thyroid cells. While methimazole and propylthiouracil significantly inhibited lectin-induced MHC class II (HLA-DR) antigen in crude human thyroid monolayer preparations these drugs had no influence on gamma-interferon induction of class II antigens in similar cell preparations. Hence, antithyroid drugs probably had a direct effect on thyroid monolayer T cells which are known to effect the lectin induction of MHC class II antigen via T-cell secretion of the cytokine, gamma-interferon (IF). Sodium iodide, similarly, had no direct influence on human thyroid cell MHC class II antigen expression induced by gamma-IF. However, iodide significantly inhibited the gamma-IF-induced expression of MHC class II antigens in a proliferating rat thyroid cell clone derived from FRTL-5 cells (clone 1B-6). In the rat thyroid cell clone this antagonistic action appeared to be exerted via inhibition of TSH-induced proliferation. These data add further support to the multifactorial nature of the profound immunosuppressive influence of antithyroid drugs in autoimmune thyroid disease and experimental thyroiditis. In contrast, iodides may have a major, and often overlooked, influence on thyroid cell proliferation and antigen expression.

Animals↗
PubMed1989

[Isolation and identification of an amoeba of the genus Naegleria].

One pathogenic free-living amoeba, strain W042302 (Fig. 1.), was first isolated from the cooling water of a power plant in Shanghai, in April, 1986. It could result in the deaths of mice, and recovered from the brain tissue of the dead mice. This pathogenic free living amoeba could be induced into trophozoite with two flagellae (Fig. 2.). Protein patterns obtained by PAGE showed twelve bands stained by Coomassie brilliant blue R250. The isoenzyme patterns of both acid phosphatase and alkaline phosphatase of the amoebic extract exhibit only a single band, while lactate dehydrogenase is devoid of noticeable activity. From the results obtained in the present study, it is inferred that strain W042302 may be belong to Naegleria australiensis.

Amebiasis↗
PubMed1988

Results of adjuvant chemotherapy for low-stage nonseminomatous germ cell tumors of the testis with vascular invasion.

Vascular invasion has been well established as one of the prime prognostic indicators in nonseminomatous germ cell tumors of the testis (NSGCT). In a retrospective series of node negative or minimally involved patients by radiology, only eight of 28 (28.6%) survived when vascular invasion was detected, compared with 50 of 72 (69%) without vascular invasion. In 1977 a policy of adjuvant cytotoxics (vinblastine and bleomycin) was added to the radiotherapy which was standard postorchidectomy treatment at the Peter MacCallum Cancer Institute. When platinum-based combination regimens were found to be effective, the radiotherapy was discontinued. Only two relapses with the original treatment occurred with one death 10 years later. The modified Einhorn protocol used as primary postorchidectomy treatment has prevented relapse in all six cases in whom it was used. The overall survival rate at 2 to 10 years is 94%. There are important implications in these findings for the "watch policy" which is becoming increasingly popular. In our opinion patients should not be merely watched when histologic sectioning of the primary reveals invasion of the vessels, of whatever type, by the tumor. Instead they should be treated.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

The effect of high energy shock waves (HESW) on human bone marrow.

The effect of High energy shock waves (HESW) on the viability and proliferation of normal human bone marrow cells was evaluated. A dose dependent increase in cytotoxicity with an increase in the number of HESW was demonstrated. In general 700 HESW immediately reduced the cell viability of bone marrow cells by 50%. The CFU-GM assay provides a method to evaluate the effect of HESW on the proliferative capacity of bone marrow. Following HESW treatment the colony forming ability of trypan blue excluding cells also felt in a dose dependent fashion, but some variation in sensitivity was noted. By comparing the sensitivity of various cells, the cells of normal human bone marrow were felt to be less sensitive to HESW effects than those of other tissue cultured cells or malignant cell lines.

Bone Marrow↗
PubMed1988

The use of single sample clearance estimates to probe hepatic drug metabolism in rats. I.

1. Conditions were examined under which estimates of drug clearance made from a single measurement of plasma concentration effectively represented multisample estimates of clearance. When plasma concentrations were measured at various post-dose times, both individual and mean values of single sample clearance estimates, Cl, corresponded closely to multisample clearance estimates, Cl, and significant differences between Cl and Cl could not be detected. 2. Best post-dose sampling times were: theophylline, 6 h; phenytoin, 2 h; valproic acid, 20 min; antipyrine, 4 h; and S-warfarin, 48 h. 3. When theophylline clearance was evaluated by both multisample and single sample experiments during diethyl ether versus urethane anaesthesia, clearances were about 50% slower for ether-anaesthetized rats. This outcome was qualitatively and quantitatively the same regardless of whether single sample or multiple sample clearances were estimated, and single sample theophylline clearances were virtually identical to multisample clearances under both anaesthetic conditions. 4. We conclude that multiple drugs can be potentially useful for probing hepatic drug metabolizing activity in rats when using a single plasma measurement to estimate clearance. An appropriate array of such probes might effectively be used to handprint host-factor influences on drug metabolizing activity.

Animals↗
PubMed1988

The use of single sample clearance estimates to probe hepatic drug metabolism in rats. II.

1. Single sample clearance estimates, Cl, were calculated for each of five drugs employed as probes of hepatic drug-metabolizing activity in rats. Probe drugs were theophylline, phenytoin, valproic acid, antipyrine, and S-warfarin. Cl values were calculated for each probe in animals pretreated with phenobarbital, isosafrole, beta-naphthoflavone, or clofibrate. Control animals were pretreated with vehicle only. 2. A clearance index (c.i., probe Cl after pretreatment divided by probe Cl control) was calculated for each probe and each pretreatment regimen, and data were consolidated to give different probe-based handprints of the pretreatment effects. 3. S-Warfarin was the least specific probe as its c.i. was greater than 1.0 subsequent to each pretreatment. Theophylline appeared to be the most selective probe since its c.i. deviated significantly from unity (3.56) only after beta-naphthoflavone pretreatment. Phenytoin exhibited c.i. values less than unity after each pretreatment indicating that it may not, when used as a single sample probe of hepatic drug-metabolizing activity, effectively discriminate between inductive or inhibitory effects of xenobiotics. 4. Multi-probe-based handprints of hepatic drug-metabolizing activity structured from simple single sample estimates of probe clearance have potential in the rapid screening of xenobiotic-induced alterations of drug-metabolizing enzyme activity.

Animals↗
PubMed1988

Ethosuximide disposition kinetics in rats.

1. Single and multiple dose disposition kinetics of ethosuximide were studied in male Sprague-Dawley rats following intravenous administration. 2. The plasma disappearance of a single 35 mg/kg dose followed for 75 h was not linear. A dose-ranging study suggested that the apparent non-linearity of ethosuximide's plasma disappearance might be due to enzyme induction over time with the drug exhibiting a faster elimination from 24 h onward. 3. Ethosuximide, after only two daily doses of 35 mg/kg/day, shortened pentobarbital-induced sleep in rats. The clearance of ethosuximide was also significantly faster after four daily 35 mg/kg doses than after a single 35 mg/kg dose. 4. Single sample clearance estimates calculated from ethosuximide concentrations prior to enzyme induction, viz. up to 24 h post-dose, were practically identical to multiple sample clearance values. Both single and multiple sample clearances were calculated assuming linear rather than non-linear elimination.

Animals↗
PubMed1988

Lactational response to soybean meal, heated soybean meal, and extruded soybeans with ruminally protected methionine.

Seventy-three high producing Holstein cows were arranged in a 3 X 2 factorial to evaluate three protein supplements (soybean meal, heat-treated soybean meal, and extruded blend of soybeans and soybean meal) without or with 15 g/head/d of ruminally protected DL-methionine during wk 4 through 16 postpartum. Total mixed diets contained (DM basis) 30% corn silage, 15% alfalfa hay, and 55% of the respective concentrate mix. Milk production was higher when cows were fed either heated soybean product instead of soybean meal. Methionine supplementation increased production when fed with soybean meal (32.2 and 33.8 kg/d) but not when fed with heat-treated soybean meal (34.5 and 33.0 kg/d) or extruded soybeans (36.2 and 34.4 kg/d). Milk fat percentages were lower with extruded soybeans (3.01, 2.93, and 2.66) and were similar without (2.83) or with (2.90) supplemental methionine. Milk protein percentages were highest when fed soybean meal, lowest with extruded soybeans (3.02, 2.92, and 2.87), and higher with supplemental methionine (2.91 and 2.96). Dry matter intake was higher when fed supplemental methionine (20.0 and 21.3 kg/d). Production of milk in early lactation high producing dairy cows was increased by supplementing a soybean meal diet with ruminally protected methionine or by replacing the soybean meal with heat-treated soybean meal, soybeans, or a mixture of the two.

Animal Feed↗
PubMed1987

Lectin-binding characteristics of mouse oviduct and uterus associated with pregnancy block by autologous antiprogesterone monoclonal antibody.

Oviducts and uteri were removed from BALB/cJ and F1 (CBA/Ca X BALB/cJ) mice at known stages post coitum and following treatment with an antiprogesterone monoclonal antibody (DB3) or a non-specific immunoglobulin (DNP). Thin sections of tissue were prepared and reacted with fluorescent conjugates of a wide range of lectins to determine if saccharide alterations were associated with the pregnancy-inhibiting effect of the DB3 antibody in BALB/c, but not F1, individuals. The ampullary region of the DB3-treated BALB/c mice showed the most marked changes, with an almost total inhibition of lectin binding, particularly for N-acetylglucosamine residues. There was also a reduced affinity for a lectin reactive with N-acetylgalactosamine in the uteri of DB3-treated BALB/c mice, associated with an extended expression during gestation of this saccharide in the proximal region of the oviduct in such mice. These are the first biochemical alterations in reproductive tract epithelia to be associated with the efficacy of the DB3 antibody in preventing pregnancy.

Animals↗
PubMed1987

Cloning the Fisher rat thyroid cell line (FRTL-5): variability in clonal growth and 3,'5'-cyclic adenosine monophosphate response to thyrotropin.

To investigate the stability of FRTL-5 cells we cloned stock cells by limiting dilution in a 6-hormone medium with bovine TSH (bTSH) (10 mU/ml) (6H medium). One third of the wells with irradiated fibroblast feeder cells developed FRTL-5 colonies. One hundred and twenty clones were obtained, of which 29 (8%) developed sufficiently for functional analysis. Clones were tested for growth responses to bTSH stimulation as evidenced by 72-h [3H]thymidine uptake and TSH receptor activation by cAMP generation. Clonal growth responses to bTSH were of three types: dose-related growth increase, absence of growth stimulation, and stimulation by bTSH in concentrations up to 100 microU/ml and inhibition of growth above 100 microU/ml. All clones tested showed evidence of extracellular cAMP accumulation in response to bTSH. However, sensitivity to bTSH varied from 1 to 100 microU/ml and maximum cAMP secretion with 1 mU/ml bTSH varied from 2 to 13 pmol/ml. Whereas certain clones showed high sensitivity to bTSH with respect to both growth and cAMP responses (e.g. 1B-6), there were clones which showed disparity in this relationship, as evidenced by poor growth dependency but high cAMP responses or by growth stimulation yet insensitivity with respect to cAMP secretion. These data demonstrate that the FRTL-5 line contains cells with variable responsiveness to bTSH. Whereas the FRTL-5 line is heterogeneous and subject to developmental variation, cloning by limiting dilution allows the derivation of highly bTSH-sensitive cells, such as 1B-6, from the stock cultures.

Animals↗