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Biomedical subjects

Y H Cheng

Publications and source records attributed to Y H Cheng.

At least 37 records · Page 2Linked to original sources
PubMed1997

Explaining disablement in modern times: hand-injured workers' accounts of their injuries in Hong Kong.

In this paper, an attempt is made to explore how people respond to injuries at work among a group of hand-injured workers in the context of contemporary Hong Kong society. Qualitative research methods were adopted. A "focused interview" by means of open-ended questions was employed to investigate those workers who have suffered from work-related injury for over 10 years. Concerning the perceived cause of the injury, the industrial production process such as machine defects, piecework, limited working experience, and lack of supervision triggered the onset of the injuries which resulted in permanent disability. At the same time, respondents tellingly explained their injury in terms of magical-religious forces such as fate and luck. This kind of understanding is embraced in cultural beliefs that are commonly found among Chinese. Such understandings appear fatalistic but allow the individual to actively cope with such misfortune. The emphasis on harmony and stability among Chinese also affected what action they took against the employer for negligence. It was shown that in general many respondents were bound by kuan-hsi (personal relationship) and tended to preserve the harmony between themselves and their employer. In modern societies like Hong Kong, traditional values and modern practices are complementary to each other in coping with life stresses such as disablement. Modernity does not provide a solid means for people to have more control over their lives. Many people still stick to their habituated lifestyle as a guiding light in day-to-day matters. Concerning risk assessment in relation to work safety, workers' value systems and practices on the shopfloor should be taken into consideration.

Accidents, Occupational↗
PubMed1996

Immobilization of prostaglandin synthetase by hydrophobic adsorption.

In this article, the immobilization of prostaglandin synthetase on n-alkyl or aryl amino-agar beads by hydrophobic adsorption is reported. The effects of different hydrophobic groups in the agar beads, pH of buffer, concentration of salts on the adsorption of prostaglandin synthetase, and the properties of immobilized prostaglandin synthetase were also studied. The results showed that 20-35 mg of microsome containing PG synthetase (protein content 8-15 mg) could be adsorbed on each gram of n-dodecylamino-agar beads after suction drying the gel in the buffer of pH 5.5 (containing 0.5 mol/L KCl), 0.1 mol/L citric-phosphate at 4 degrees C. The remaining immobilized enzyme activity was over 80%. The optimum pH of immobilized PG synthetase is 8.0, similar to that of the native enzymes. The thermostability of immobilized PG synthetase in the buffer containing 0.5 mol/L KCl was increased. Immobilized PG synthetase was used as a catalyst of synthesis of prostaglandin E1. The preservation of activity after 10 working cycles was 86.2%.

Adsorption↗
PubMed1996

Knowledge and attitudes about smoking in medical students before and after a tobacco seminar.

A 3-hour seminar on tobacco was introduced to second year (pre-clinical) medical students in Hong Kong in 1994. The differences in knowledge and attitudes were measured by a self-administered and anonymous questionnaire with 14 items before the seminar (n = 145), and again 2 weeks after the seminar (n = 151). The students also completed an evaluation form at the end of the seminar. Before the seminar, the students were most deficient in their knowledge on the exact magnitude of the risks from smoking and on the risks from smoking relative to the risks from air pollution and asbestos. After the seminar, their knowledge increased significantly (P < 0.005). As for attitudes, in the pre-test 35% strongly agreed that tobacco advertising should be completely banned, and 50% did so in the post-test (P = 0.02). The corresponding figures for banning of all forms of tobacco promotion were 26% and 43% (P < 0.005). In the pre-test, one in four students strongly disagreed that doctor's advice to their patients to stop smoking is totally ineffective, with this proportion increasing to 70% in the post-test (P < 0.005). The majority of the students stated that the seminar was useful. The preclinical medical curriculum should, at the very least, include a tobacco seminar. Our survey shows that it is effective in improving students' knowledge and attitudes on tobacco control.

Adult↗
PubMed1995

[Study on risk factors of vaginitis in married women at reproductive ages in rural areas Luliang County, Yunnan Province].

Utilizing data from 2,287 married women at reproductive ages from Luliang county in Yunnan province, a study of prevalence and risk factors of vaginitis was conducted. It is found that the prevalence of vaginitis in Luliang county was 10.2%. The main risk factors selected by Logistic regression were occupation, contraceptive methods used currently, numbers of pregnancies, sexual intercourse per month, habit of washing lower body with dirty water during menses etc. The main risk factors through chi 2-test were age, occupation age of marriage, numbers of pregnancies, numbers of induced abortion, numbers of natural abortion, numbers of stillbirth, numbers of total failing pregnancies, contraception methods used currently, contraception methods ever used before, intercourse per month, wash lower body with dirty water during menses.

Adolescent↗
PubMed1995

[Feasibility assessment of skin permeation for the local anesthetic lidocaine].

In this paper, the feasibility of skin permeation for lidocaine and pressure sensitive adhesive (PSA) tape formulation containing lidocaine for skin local anesthetic were assessed. Firstly, in vitro skin permeation of the molecular and ionic forms of lidocaine from water and silicone fluid suspensions was measured using a side-by-side two diffusion cells and excised hairless rat skin. Secondly, PSA tape containing lidocaine was prepared by a general casting method using styrene-isoprene-styrene block copolymer. The in vitro release and skin permeation were evaluated and compared with that of Japan marketed xylocaine jelly. The effect of lidocaine concentration on the steady-state flux of skin permeation from 10% to 60% lidocaine PSA tapes was also evaluated.

Anesthetics, Local↗
PubMed1994

A new kind of immobilized lipase in organic solvent and its structure model.

In this paper, we used Ca-alginate gel beads coated with polyetheneimine and glutaraldehyde to adsorb Expansum penicillium lipase. The immobilized lipase catalyzed esterification of 1-dodecanol with dodecanoic acid in benzene. The results show that when the concentration of Ca-alginate, polyetheneimine (PEI) and glutaraldehyde is 1%, 6% and 1%, respectively, the activity of the immobilized lipase and the amount of adsorbed protein are the highest. The immobilized lipase is better than the SDS-immobilized lipase. The activity of the immobilized lipase connected by glutaraldehyde is higher than the activity of that without glutaraldehyde. The initial rate of the immobilized lipase and lyophilized lipase powder is 5.9 x 10(2) nmol/min.mgpr and 2.8 x 10(1) nmol/min.mgpr, respectively. After the immobilized lipase catalyzed the esterification reaction at 37 degrees C for about 12 hours, 93.3% of 1-dodecanol was converted to ester, but for lyophilized lipase powder, only 17.5% converted. Based on all above results, we have presumed and explained the structure of this kind of immobilized lipase.

Alginates↗
PubMed1994

Effect of skin surface lipid on the skin permeation of lidocaine from pressure sensitive adhesives.

Pressure sensitive adhesives (PSA) tapes containing different concentrations of lidocaine were prepared by a general casting method using styrene-isoprene-styrene block copolymer, and the in vitro skin permeation of lidocaine from each tape was evaluated using diffusion cell and excised hairless rat skin. The skin permeation was proportionally increased by up to 40% lidocaine in the PSA tape and did not change after this concentration. Although the bending point of the steady-state flux via skin concentration curve was found at 40%, saturated concentration or solubility of lidocaine in the tape was estimated to be about 20% by differential scanning calorimetry (DSC) measurement. In addition, the steady-state flux of lidocaine through skin from water or silicone fluid suspension (92 or 120 micrograms/cm2.h, respectively) was very similar to those of 40, 50 and 60% tapes (105, 101 and 112 micrograms/cm2.h, respectively). Decrease in the concentration in tapes during the permeation experiment explained only part of these phenomena. To analyze them further, the drug free PSA tape with or without (control) skin surface lipid was affixed to 50% lidocaine PSA tape for 48 h, and the amount of lidocaine crystal in the layered tapes was measured by DSC. The amount was found to be lower in the lipid-containing tape than in the lipid-free tape, suggesting that skin surface lipid can dissolve lidocaine crystal or solid in PSA tape to decrease its thermodynamic activity. Thus it is important to follow the concentration and thermodynamic activity of lidocaine in PSA tape, skin and the interface between the two layers to exactly assess its skin permeation flux.

Adhesives↗
PubMed1994

[Studies on cisplatinum albumin microspheres for lung targeting].

An optimum procedure was established by orthogonal test for preparing cisplatinum albumin microspheres (CDDP-BSA-MS) with emulsion-chemical cross-linking. The quality, stability, distribution in vivo, kinetic characteristics and safety of the albumin microspheres were studied. The results showed that the surface was regular, the mean size was 13.13 +/- 3.55 microns, embedding ratio was 21.62% and the release characteristics in vitro were in accord with "biphase kinetics equation". The stability of the albumin microspheres was good after three months storage. The microspheres accumulated almost entirely in the lung 15 minutes after intravenous injection to mice. The total amount in the lung was about 97% of the injected dose at the peak concentration. Two-compartmental model can be used to describe the regulation of the pharmacokinetics of albumin microspheres in lung. Observation of the lung slice of mice showed no pathological damage.

Animals↗
PubMed1993

[Optimization of the preparing process for sinitang drop pills by orthogonal test].

The preparing process for Sinitang drop pills was optimized by orthogonal test. The results from nine experiments were subjected with three indexes to objective analysis and variance analysis, and an optimum preparing process for Sinitang drop pills was sieved out. The quality of the drop pills prepared in this way was examined to be up to the standard.

Dosage Forms↗
PubMed1993

[Study on sodium norcantharidate albumin microspheres].

In this paper sodium norcantharidate (Na2NC) was chosen as model drug and sodium norcantharidate albumin microspheres (Na2NC AM) was prepared by an optimal procedure. The embedding nature, appearance, morphology, size and size distribution, release characteristics in vitro, freeze-drying, 60Co radiosterilization and stability of Na2NC AM were tested. The results showed that the mean size was 0.43 +/- 0.12 micron, embedding concentration was 20.34-26.75 micrograms/mg, embedding ratio was 21.9-26.4%, release characteristics in vitro was in accord with Higuchi equation. Freeze-drying and 60Co radiosterilization showed no influence on Na2NC AM. The stability of Na2NC AM was good after 3 months storage.

Bridged Bicyclo Compounds↗
PubMed1993

[Study on cisplatin albumin microspheres for neck external artery embolization].

In this paper the technique of emulsion chemical-crosslinking was used to prepare cisplatin albumin microsphere for jaw squamous cancer by neck external artery embolization. It was yellow powder with yield 80 +/- 5%, mean size 56.3 microns, cisplatin concentration 14.02-14.20%, loading rate 97.08-97.95%. The release characteristics in vitro, sterilization, stability and recipe of disperse solvent of cisplatin albumin microsphere were investigated. Animal test showed that cisplatin albumin microsphere may plug the branches of neck external artery well and remain in local tissue.

Animals↗
PubMed1993

[Study on albumin microspheres as drug carrier for liver targeting].

In this paper 6 factors and 12 levels of each variable were selected by Uniform Design Method and computer for preparing albumin microspheres with emulsion-chemical cross-linking. An optimal procedure for preparing albumin microspheres was established and the mean diameter of albumin microspheres is 0.41-0.47 micron. Albumin was labelled with 125I-isotope and 125I-albumin microspheres were prepared according to the optimal procedure. The suspension of 125I-albumin microspheres with 0.1% Tween-80 saline was injected via mice tail vein. The animals were sequentially killed and the radioactivity of blood, spleen, liver, kidney, stomach, heart, lung, thyroid and brain were measured. The results showed that albumin microspheres were accumulated mainly in the liver, about 68% of the injected dose at the peak concentration. The pharmacokinetics of albumin microspheres in liver was also studied and two-compartmental model can be used to describe the regulation.

Animals↗
PubMed1990

[Effect of several factors on enzymic activity and antigenicity in chemical modification of L-asparaginase].

Acetic anhydride, dextran and monomethoxypolyethylene glycol and different modification methods were used for modification of L-asparaginase to maintain enzyme activity and completely remove its antigenicity. The results showed that the macromolecular modifiers PEG and dextran were better than the small molecular modifier acetic anhydride. For maintenance of enzyme activity and removal of antigenicity modification in the presence of substrate was better than absence of substrate and activated PEG2 was better than activated PEG1. When PEG2-L-asparaginase was modified in the presence of substrate, its antigenicity was completely removed, while more than 30% of native enzyme activity were still retained.

Acetic Anhydrides↗
PubMed1989

[Effects of the preparation of xiao long ling on experimental prostatic hyperplasia in mice].

The results of the experiments indicate that the prostatic hyperplasia caused by Testosteroni Propionatis in mice, cotton oil-induced local swollen ears of mice and the proliferation of granuloma produced by subcutaneous implantation of cotton pill in rats are inhibited significantly by the preparation of Xiao Long Ling. Xiao Long Ling depresses the increase of vascular permeability induced by a variety of inflammatory media such as histamine, 5-HT and PGE. Xiao Long Ling is found capable of inhibiting the platelet aggregation induced by ADP as well as depolymerizing the aggregated platelets.

Animals↗