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Biomedical subjects

X Q Gu

Publications and source records attributed to X Q Gu.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Studies on decomposition kinetics of thalidasine in aqueous solution].

In this report, the decomposition kinetics of thalidasine (TD) in aqueous solution at pH 2.0-7.8, salt concentration 0-0.132 mol/L, temperature 50, 60, 70, 80 degrees C, and different oxygen concentrations were investigated. The decomposition rate constant of TD in aqueous solution were determined by fluorescence spectrophotometer. The results showed: the oxidation reaction contributed largely to the overall decomposition, the oxidation rate of TD was found to be chiefly dependent on the PH of the medium and presence of oxygen. When in excess oxygen, the reaction followed pseudo first-order kinetics with respect to TD concentration. The rate constant can be expressed as: [formula: see text]. No primary salt effect was observed at pH 7.2.

Antineoplastic Agents, Phytogenic↗
PubMed1990

Targeting behavior of hepatic artery injected temperature sensitive liposomal adriamycin on tumor-bearing rats.

Temperature sensitive liposomal Adriamycin (LADM) was injected into the hepatic artery of rats bearing implanted hepatic tumors. Two hours after the injection, the liver was heated at 42 degrees C and maintained for six minutes at that temperature using local hyperthermia. Blood samples were taken at regular intervals until 8 hours after injection, at which time the animals were sacrificed and the drug distribution in the tissues was examined. Results indicate that the Adriamycin was released from the liposome, with the drug concentration in circulation peaking at 30 minutes after heating. High drug levels (25.2 micrograms/g of wet tissue) in the tumor and high tumor/liver Adriamycin level ratios (TLAR; 4.1) were found. The drug levels and the TLAR of the liposomal Adriamycin injection combined with heating (LADM H) were significantly different from those of the same dose of aqueous Adriamycin with heating (ADM H) or aqueous Adriamycin (ADM) and LADM without heating. The experiment shows that the LADM is cleared from the liver slowly, and when hyperthermia treatment at phase-transition temperature of the liposome is performed, the drug level in an implanted hepatic tumor is increased, and in the parenchyma is decreased. The results imply that targeting the hepatic tumor in this way may be an effective therapeutic method, and the drug release from the liposome may be controlled externally. This method appears promising for clinical practice.

Animals↗
PubMed1989

[Studies on the stability and some other important physical properties of polysaccharides polyphase liposome (PPL)].

The stability and some other important physical properties of PPL were investigated by means of electron microscopy and MPV-TAS experiments. The results are rated as follows: Good integrity of liposome homogeneity of its particle size were reached, and at 100 degrees C PPL was found to undergo sterilization without causing changes of its shape and encapsulation efficiency for 1 h. Also, the distribution of PPL particle size and the regularity of the change of PPL particle in size were determined by Coulter counter. Using this method, the kinetic equation of coalescence of polyphase liposome and the activation energy for coalescence were obtained, and through these results the stability of PPL is elucidated.

Drug Carriers↗
PubMed1989

New challenges for occupational health services facing economic reform in China.

In China, which is facing economic reform and the rapid development of small-scale industries, various occupational hazards are reappearing. The problems are related to the ignorance of the managers and the workers, a lack of capital, the insufficiency of occupational health services, and the transfer of some hazardous work from large factories in the cities to small plants in the towns and villages. The change in life-style, especially in smoking habits, has aggravated occupational hazards. The problems may be solved by renewing the concept of health among the managers and workers, enforcing legislation related to occupational hazards, strengthening health personnel training, and reinforcing health education and self-help.

China↗
PubMed1988

An epidemiological study on farmer's lung among hay grinders in Dafeng County.

This article reports on an epidemiological survey of the presence of farmer's lung among 1054 farmers who grind moldy hay. The prevalence was 8.3-11.4%. The main pathogen was Thermoactinomyces vulgaris. The factors which influenced farmer's lung were the moldy state of the hay and the dust concentration. The epidemiological features of farmer's lung are analyzed and discussed and certain preventive measures are suggested.

Adult↗
PubMed1987

Discrepancies in the study of byssinosis in China.

The existence of byssinosis in China was first reported in 1964. Detailed studies only started in the late 1970s and early 1980s. The work of the WHO study group as edited by the Technical Report Series no. 684, "Recommended health-based occupational exposure limits for selected vegetable dusts," promotes the further study of occupational disease in China; a few points need further discussion. The word byssinosis translated in Chinese is misleading as to the real pathogenesis of the disease. Some still believe cotton dust causes interstitial fibrosis, while the majority of researchers agree with the WHO study group. A poorly designed animal model may have led to the (incorrect) conclusion that dust from carding room is toxic if it is injected intratracheally. The reasons for the controversy in the prevalence of byssinosis in different reports in earlier years are the different diagnosis criteria and the fact that dust sampling methods were not standardized; pulmonary function tests were not used as a routine index; chronic bronchitis and smoking are now recognized as confounders and should have been considered. This Institute initiated the hygiene standards study on cotton dust and recommended 1 mg/m3 for respirable dust and 3 mg/m3 for total dust. If a reduction in dust levels could prevent byssinosis, it would likely also control the risk factor for developing bronchitis.

Byssinosis↗
PubMed1986

Primate model of neovascular glaucoma.

Iris neovascularization has been reproducibly created in cynomolgus monkey eyes by argon laser occlusion of retinal veins. Pre-treatment of the eyes with lensectomy and vitrectomy (before the retinal vein occlusion) led to a more rampant development of the iris neovascularization in all eyes, as well as development of neovascular angle closure glaucoma in two of the 12 eyes. Histopathologic examination confirmed the finding of neovascular angle closure. This primate model may allow further investigation into the causes and therapy of neovascular glaucoma.

Animals↗
PubMed1986

Toxicity of dipterex: a field study.

This study summarises historical surveillance data collected from 1977 to 1982 and the results of a field study conducted thereafter (1983-4) in a dipterex packing workshop. The findings suggest that both airborne dipterex and dermal contamination contribute to the inhibition of blood cholinesterase (ChE) and that cases of poisoning in hot seasons can be attributed mainly to dermal absorption. At a level of 0.5 mg/m3, dipterex is shown to lead to a mild but appreciable inhibition of ChE activity. The results also indicate that blood ChE monitoring was sensitive both for long term and short term exposed workers. As a result, the recommendation that the maximum allowable concentration for airborne exposure to dipterex be revised to 0.5 mg/m3, can be regarded at providing only for relative safety.

Air↗
PubMed1985

Ocular neovascularization. Tissue culture studies.

The proliferative activity of a number of intraocular fluids, bovine retinal extract, and normal serum (from humans and cynomolgus monkeys) was investigated by in vitro tissue culture studies, with the use of tritiated thymidine incorporation by the cultured endothelial cells of human umbilical veins. There was increased tritiated thymidine incorporation by (1) the aqueous, vitreous, and intraocular fluid (IOF) (which filled the eye after lensectomy and vitrectomy) removed from cynomolgus monkey eyes with iris neovascularization or with neovascular glaucoma (NVG) that developed after experimental retinal vein occlusion, (2) by aqueous and vitreous removed from human eyes with NVG or proliferative diabetic retinopathy; (3) by the serum, and (4) by the bovine retinal extract. However, tritiated thymidine incorporation was not increased by the normal aqueous, vitreous, or IOF.

Animals↗