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Biomedical subjects

K Tsang

Publications and source records attributed to K Tsang.

14 recordsLinked to original sources
PubMed2001

The prediction of body composition in Chinese Australian females.

OBJECTIVE: To determine the efficacy of applying specific body composition techniques to, and assess the relationship between body mass index (BMI) and body fat levels for Chinese Australian females. DESIGN: Statistical comparative analysis of body composition techniques. SUBJECTS: Australian resident females of Chinese extraction (n=40) (aged 18-45 y, mean 32.5+/-8.0; BMI range 15.7-30.9 kg/m2, mean 21.7+/-3.1 kg/m2, median 20.8 kg/m2). MEASUREMENTS: Body composition determined using bio-electrical impedance analysis (BIA), the skin-fold equations of Durnin and Womersley (D&W) and a deuterium dilution technique. Body size was calculated as the body mass index (BMI) weight/height(2) (kg/m2). RESULTS: With a median BMI of 20.8, range 15.7-30.9, an acceptable BMI existed for 87.5% of the subjects (mean (s.d.) 21.7+/-3.1 kg/m2). Percentage fat mass (%FM) from the deuterium dilution technique (mean (s.d.) 35.6+/-6.4) suggested 75% were overweight or obese. %FM from the D&W equation (mean (s.d.) 28.0+/-3.9) and BIA (mean (s.d.) 29.4+/-5.1) also indicated a tendency towards overweight or obese. The deuterium technique was significantly correlated and significantly different to the D&W eqn, r=0.71 P=0.001; and BIA, r=0.77, P=0.001. Bland and Altman analysis indicated that bias existed between the techniques (BIA mean (s.d.)-6.7+/-4.1) and D&W equation mean (s.d.)-6+/-4.5) when compared to the deuterium method. CONCLUSIONS: Despite a low mean BMI, body fat levels determined by the three methods suggested that, overall, an unsatisfactory body composition existed. The levels of overweight and obesity (%FM>30) were higher than reported in previous research despite a mean BMI lower than the Australian national average. Comparative analysis suggested that the body fat prediction techniques used may be precise but not accurate. Comparative results obtained for the BIA and D&W equation techniques suggest an overestimation of body fat levels for leaner individuals and under estimation for overfat individuals. The results support the notion that accurate determination of body composition and the determination of appropriate body size may require equations developed for specific ethnic populations.

Adolescent↗
PubMed1998

Effective treatment of high-grade lymphoproliferative disorder after renal transplantation using autologous lymphocyte activated killer cell therapy.

Posttransplantation lymphoproliferative disorders (PTLD) is not uncommon and can occur in 2% to 5% of solid organ recipients on immunosuppression. Epstein-Barr virus (EBV) infection or reactivation and intensive anti-T lymphocyte treatment are important pathogenetic factors for a large proportion of these disorders. Nonclonal lesions with polymorphous histology have a potential for regressing when the immunosuppressants are reduced or stopped. Clonal tumors with a monomorphous histology carry a poor prognosis, and the mortality rate for monoclonal lymphoma has been reported as high as 80%. We report a renal transplant recipient who developed high-grade monoclonal lymphoma only 4 months after a live-donor transplantation. The tumor was EBV positive. Reduction of immunosuppressants resulted in minimal regression of the tumor. The patient was treated with adoptive immunotherapy using ex vivo generation of autologous lymphocyte activated killer (LAK) cells. She had leukapheresis, and autologous peripheral blood mononuclear cells were obtained and cultured in interleukin-2 (IL-2)-rich medium for 9 to 10 days. The IL-2-activated LAK cells were reinfused into the patient without any systemic administration of IL-2. The patient experienced no side effects during the infusion. There was no rejection episode, and the renal function of the patient remained stable after treatment. Computed tomography scan performed 2 months after the infusion showed marked regression of the lesions in the liver and spleen. Five months later, magnetic resonance imaging showed complete resolution of the tumor lesions. Ultrasonography 13 months after the LAK cell infusion showed no lesion. The allograft function was not affected after treatment. Adoptive immunotherapy using IL-2-activated autologous LAK cells was effective in treating this renal transplant patient with EBV-positive high-grade lymphoma. The patient's kidney allograft functioned well without any rejection.

Adult↗
PubMed1998

Modelling cortical cataractogenesis XX. In vitro effect of alpha-lipoic acid on glutathione concentrations in lens in model diabetic cataractogenesis.

In previous studies stereospecific protection against lens opacity was consistent with specific reduction of R-alpha-lipoic acid(R-alpha-LA) in mitochondria of the vulnerable cells at the lens equator where the first globular degeneration is seen in glucose cataract. In this study two further possible explanations of this effect were investigated: (1) increased glucose uptake by the lens, leading to increased glycolysis and release of lactate into the incubation medium and/or (2) maintenance of glutathione levels by the R-alpha-LA. The data did not support 1, but was consistent with 2, after 24 hr incubation. The concentrations of glutathione in normal lenses or lenses incubated with R- or racemic alpha-LA were not significantly different, but the concentration of glutathione in lenses incubated with S-alpha-LA was significantly lower than the R-alpha-LA-incubated lenses.

Animals↗
PubMed1997

Ozone depletes tocopherols and tocotrienols topically applied to murine skin.

To evaluate ozone damage to hairless mouse skin, two parameters of oxidative damage, vitamin E depletion and malondialdehyde (MDA) production, were measured in vitamin E-enriched and in control skin from mice exposed to ozone (10 ppm). A 5% vitamin E solution (tocotrienol-rich fraction, TRF) in polyethylene glycol (PEG) was applied to 2 sites on the back of hairless mice, PEG to 2 sites. After 2 h, the sites were washed, one of each pair of sites covered and the mice exposed ozone for 2 h. Ozone exposure (compared with covered sites) increased epidermal MDA in PEG-treated sites, while vitamin E was unchanged. In contrast, ozone exposure significantly depleted vitamin E in TRF-treated sites, while significant MDA accumulation was prevented. This is the first demonstration that ozone exposure causes damage to cutaneous lipids, an effect which can be attenuated by vitamin E application.

Administration, Topical↗
PubMed1997

In vivo exposure to ozone depletes vitamins C and E and induces lipid peroxidation in epidermal layers of murine skin.

To evaluate skin susceptibility to ozone (O3) and to localize possible oxidative damage within the skin layers, hairless mice were exposed to 10 ppm O3 or air (0 ppm O3) for 2 h. The mice were euthanized, the skin removed and frozen. Three skin layers (upper epidermis, lower epidermis/papillary dermis, and dermis) were separated, antioxidant concentrations (alpha-tocopherol and ascorbic acid) and the lipid peroxidation product malondialdehyde (MDA) measured. In the upper epidermis, O3 significantly depleted alpha-tocopherol (22%; p < .05) and ascorbic acid (55%; p < .01). These antioxidants were unchanged by O3 in the lower skin layers. More remarkably, MDA increased ten-fold in the upper epidermis (p < .001) and two-fold in the lower epidermis/papillary epidermis (p < .05); it was unchanged in the dermis. Thus, exposure to O3 in vivo depletes ascorbic acid and alpha-tocopherol and strongly induces lipid peroxidation in skin. High MDA concentrations measured in the upper epidermis suggest that O3 reacts directly with fatty acids on the skin surface layers. These results further suggest that chronic exposure to lower O3 concentrations found in urban smog could potentially have implications for skin health.

Animals↗
PubMed1993

Primary lymphoma of the kidney in the acquired immunodeficiency syndrome.

An increased incidence of lymphoma has been reported in patients with the acquired immunodeficiency syndrome. Malignant lymphomas that develop within this setting of impaired immune surveillance have distinctive clinical, histologic, and molecular biologic characteristics. Histologically, the majority of these lymphomas are small noncleaved cell or immunoblastic lymphomas, and are B-cell phenotype by immunophenotypic and immunoglobulin gene rearrangement studies. In contrast with malignant lymphoma occurring in the general population, extranodal origin is common in acquired immunodeficiency syndrome-related non-Hodgkin's lymphomas, with the central nervous system, bone marrow, gastrointestinal tract, and liver being the most common sites. To the best of our knowledge, there has been no description in the literature of primary renal lymphoma occurring in patients with the acquired immunodeficiency syndrome. We report an unusual case of primary non-Hodgkin's lymphoma (diffuse B-cell immunoblastic type) of the kidney in a patient with the acquired immunodeficiency syndrome.

Humans↗
PubMed1992

Vascular proliferation of the thyroid. A complication of fine-needle aspiration.

Fine-needle aspiration (FNA) of the thyroid has a low morbidity rate, with hematoma formation being the most commonly encountered complication. We describe two cases of exuberant vascular proliferation within the thyroid gland, one resembling a cavernous hemangioma and the other with similar changes but with areas of papillary endothelial hyperplasia. Both lesions occurred in patients with a recent history of FNA prior to the thyroidectomy procedure. The vascular proliferation was interpreted as organizational changes in a hematoma secondary to the FNA. These cases, in conjunction with a recent case of Masson's vegetant intravascular hemangioendothelioma complicating thyroid FNA, expand the literature on vascular proliferations that may develop subsequent to thyroid FNA.

Biopsy, Needle↗
PubMedDate not supplied

Body mass index and the prediction of percentage body fat in Australian Chinese women.

BACKGROUND: Body mass index (BMI) is frequently related to percentage body fat. Nevertheless the relationship between BMI and fat mass/height2 (FM/H2), theoretically, should be more appropriate. AIM: This study seeks to evaluate the relationship between BMI and both percentage body fat and FM/H2 in a group of Chinese Australian females. SUBJECTS AND METHODS: Forty subjects took part in the study and all were Chinese females resident in Brisbane, Australia. Body mass index was calculated from height and weight. Percentage body fat and fat mass were calculated from measurements of total body water. RESULTS: The use of BMI to predict FM/H2 accounted for double the variance of that found when BMI was used to predict percentage body fat. CONCLUSIONS: As a consequence, it is possible that the use of BMI to predict FM/H2 and not percentage body fat in the first instance may prove to be more useful in a number of adult populations. Nevertheless, with a relatively small sample size it is difficult, if not impossible, to test the developed equations on a validation group and further investigation into the findings described in this paper needs to be undertaken.

Adipose Tissue↗