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Biomedical subjects

G W Yip

Publications and source records attributed to G W Yip.

7 recordsLinked to original sources
PubMed2006

Up-regulation of metallothionein isoforms in keloid keratinocytes.

Keloids are proliferative growths of dermal collagen, usually resulting from excessive tissue response during wound healing. There is evidence that keratinocytes may promote keloidogenesis via epithelial-mesenchymal interactions. Metallothioneins (MTs) are known to be involved in the fundamental cellular processes of growth and apoptosis. In this study, we evaluated the expression of MT isoforms in normal and keloid keratinocytes. The expression patterns of ten functional MT isoforms were assessed using real-time RT-PCR in primary cultures of normal and keloid keratinocytes. The MT-2A isoform was the most abundant MT isoform in both normal and keloid keratinocytes while the MT-1B isoform was absent. There was a significant increase in the mRNA expression of four MT isoforms, viz. MT-1A, 1E, 1F and 2A in keloid keratinocytes as compared to normal keratinocytes. Up-regulation of MT-1A, 1E, 1F and 2A isoforms may play a part in the development of keloids by paracrine signaling.

Cells, Cultured↗
PubMed2004

Chondroitin sulfate in palatal wound healing.

Chondroitin sulfate is up-regulated in granulation tissue during wound healing. To investigate the role of chondroitin sulfate in the wound-healing process after surgical repair of cleft palate, we isolated and cultured rabbit palatal fibroblasts. Treatment with chondroitin-6-sulfate resulted in a dose-dependent increase in cell adhesion and cell proliferation, whereas the reverse effects were seen after chondroitinase degradation of chondroitin sulfate. The biological actions of chondroitin sulfate appeared to be dependent on the presence and position of sulfate groups. Inhibition of glycosaminoglycan sulfation by chlorate treatment led to reduced cell adhesion and cell proliferation and a slower rate of wound closure in vitro. Furthermore, exposure to chondroitin-4-sulfate resulted in a dose-dependent reduction in cell adhesion. Together, these results show that chondroitin sulfate is involved in palatal wound healing.

Analysis of Variance↗
PubMed2001

Lumbrical muscle with an additional origin in the forearm.

BACKGROUND: Although variations in the attachments of the lumbrical muscles have been commonly reported, these have been seen mainly in the Caucasian population. The present study is the first reported case of such an anomaly in a Chinese cadaver in the literature. METHODS: The upper extremities of 26 Chinese (23 male and three female) cadavers were examined. RESULTS: Dissection of a male 66-year-old Chinese cadaver has revealed the rare case of a bipennate first lumbrical muscle with an additional origin extending from the distal part of the forearm. Its first origin arose from the flexor digitorum profundus in the hand distal to the flexor retinaculum. The intrinsic muscles in the hands of all the other cadavers were normal. CONCLUSIONS: An anomalous origin of the lumbrical from muscles in the forearm has the potential to cause compression of the median nerve in the carpal tunnel.

Aged↗
PubMed2001

Anti-ischemic action of estrogen-progestogen continuous combined hormone replacement therapy in postmenopausal women with established angina pectoris: a randomized, placebo-controlled, double-blind, parallel-group trial.

The benefit of treating postmenopausal women with established cardiovascular disease with combined estrogen-progestogen hormone replacement therapy (HRT) is controversial. This study investigated the effect of treatment with estradiol and norethisterone acetate on exercise tolerance and on the frequency and severity of ischemic attacks in postmenopausal women with stable angina pectoris. A total of 74 Chinese women were recruited for this 16-week double-blind, placebo-controlled trial. They were randomly allocated into two groups; one group received placebo/placebo/placebo and the other group received placebo/estrogen-progestogen/placebo. Estrogen-progestogen continuous combined HRT increased both time to 1-mm ST depression (99.1 s, p < 0.05) compared with a mean decrease of 22.9 s with placebo (p < 0.05), and total exercise duration also showed a significant increase (32.7 s, p < 0.05) after treatment compared with placebo (2.5 s, p < 0.05). In addition, the total number of ischemic events/24 h during ambulatory electrocardiographic monitoring decreased by 0.82 events after treatment (p < 0.05) compared with an increase in the placebo group (0.94), a highly significant difference (p = 0.006). These results suggest that the administration of this particular combined hormone replacement preparation may have a beneficial effect on myocardial ischemia in postmenopausal women with established coronary disease.

Aged↗
PubMed1999

Comparison of frequencies of left ventricular systolic and diastolic heart failure in Chinese living in Hong Kong.

There is a wide variation (13% to 74%) in the reported prevalence of heart failure associated with normal left ventricular (LV) systolic function (diastolic heart failure). There is no published information on this condition in China. To ascertain the prevalence of diastolic heart failure in this community, 200 consecutive patients with the typical features of congestive heart failure were studied with standard 2-dimensional Doppler echocardiography. A LV ejection fraction (LVEF) >45% was considered normal. The results showed that 12.5% had significant valvular heart disease. Of the remaining 175 patients, 132 had a LVEF >45% (75%). Therefore, 66% of patients with a clinical diagnosis of heart failure had a normal LVEF. Heart failure with normal LV systolic function was more common than systolic heart failure in those >70 years old (65% vs 47%; p = 0.015). Most (57%) had an abnormal relaxation pattern in diastole and 14% had a restrictive filling pattern. In the systolic heart failure group, a restrictive filling pattern was more common (46%). There were no significant differences in the sex distribution, etiology, or prevalence of LV hypertrophy between these 2 heart failure groups. In conclusion, heart failure with a normal LVEF or diastolic heart failure is more common than systolic heart failure in Chinese patients with the symptoms of heart failure. This may be related to older age at presentation and the high prevalence of hypertension in this community.

Aged↗
PubMed1998

Effect of intraperitoneal administration of zinc on C57/6J mouse liver--a light microscopic study.

Intraperitoneal administration of zinc chloride in vivo at 14 micrograms/g body weight (equivalent to 1/2 LD50) over a 3 week period induced an increase in liver weight. The mean weight of the livers in zinc-treated C57/6J mice was 50% higher than that of control animals. Image analysis revealed a concomitant and significant increase in the cross-sectional area and perimeter of the hepatocytes in the zinc-treated group. The mean cross-sectional area of hepatocytes in the zinc-treated mice was 337.2 +/- 4.3 microns2 as compared to 224.6 +/- 2.9 microns2 in the control group (p < 0.05, Mann-Whitney test). The mean perimeter of hepatocytes in zinc-treated mice was 72.4 +/- 0.5 micron as compared to 58.9 +/- 0.4 micron in control animals (p < 0.05). It would appear that subacute administration of zinc may result in increase in liver mass due to hypertrophy of the hepatocytes.

Animals↗