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Biomedical subjects

Y T Mak

Publications and source records attributed to Y T Mak.

At least 19 recordsLinked to original sources
PubMed1992

Prediction of mortality in patients in acute medical wards using basic laboratory and anthropometric data.

The value of anthropometric and biochemical indices in predicting short-term mortality among patients in general medical wards was assessed in 294 patients admitted consecutively to a district hospital over a one month period. Using a stepwise logistic regression model and supported by the linear discriminant analysis method, mortality within 3 months could be predicted with sensitivity of 83% and specificity of 84% using the following variables: sex, functional ability, urea, total protein, alkaline phosphatase and albumin-adjusted calcium. Addition of anthropometric values and biochemical nutritional indices did little to improve the accuracy of the prediction, contrary to previous findings among surgical patients and elderly residents of long-term care institutions.

Activities of Daily Living↗
PubMed1992

Free triiodothyronine in sera of acutely ill general medical patients: a prognostic indicator?

We measured free triiodothyronine (FT3), thyrotropin (TSH), and C-reactive protein (CRP) in sera of 39 acutely ill medical patients who died within three months of admission and 39 age- and sex-matched control patients selected at random from a total of 294 acute medical admissions. Serum FT3 in nonsurvivors (1.91 +/- 1.51 pmol/L) was significantly lower than that in survivors (3.01 +/- 1.3 pmol/L, P less than 0.01) and the CRP in nonsurvivors (54.6 +/- 59.2 mg/L) was significantly higher than in survivors (43.6 +/- 59.5 mg/L, P less than 0.05). There was no difference in plasma TSH between the two groups. The estimated odds ratio relating death to a plasma FT3 value less than 1.0 pmol/L on admission was 17 (highly significant: P less than 0.001). We conclude that plasma FT3 may be a useful prognostic indicator in acutely ill patients.

Acute Disease↗
PubMed1991

Second-trimester thyroid function and pregnancy outcome in mothers with hyperthyroidism. Birth weight related to mid-trimester triiodothyronine and RBC zinc.

Thyroid function at 24-28 weeks gestation was compared between 26 mothers with hyperthyroidism (16 on antithyroid treatment and 10 in remission without treatment) and 15 normal pregnant controls. There was no difference in the total and free thyroxine (TT4 and FT4) or in the total and free triiodothyronine (TT3 and FT3) concentrations, but the erythrocyte zinc (RBC Zn) concentration was significantly lower in the study group (187.3 +/- 46.6 mumol/l RBC versus 223.6 +/- 3.7 mumol/l RBC, p less than 0.01). In the study group, both birth weight and gestation at delivery were significantly correlated with TT3 (r = -0.500, p less than 0.02 and r = -0.460, p less than 0.05, respectively) as well as with RBC Zn (r = 0.473, p less than 0.02 and r = 0.573, p less than 0.01, respectively). The results suggest that plasma concentration of TT3 and of RBC Zn at 24-28 weeks gestation may be helpful prognostic factors in the management of pregnant patients with hyperthyroidism.

Adult↗
PubMed1991

A comparison of the nutritional status of elderly Chinese living in different types of non-acute care institutions in Hong Kong.

The nutritional status of 191 elderly subjects living in three types of non-acute care institutions was studied by estimating nutrient intake and biochemical status. The dietary intake of women in the long-stay institution was similar to that of free-living elderly subjects. Dietary consumption of subjects living in a private nursing home and a convalescent unit were poorer than for elderly free-living subjects. Elderly women in all institutions had a poorer protein nutritional status, a poorer biochemical status of vitamin B12, folate, ascorbic acid, and vitamin D, and lower plasma potassium levels when compared with free-living elderly women. Those in the private nursing home and the convalescent unit had the poorest protein nutritional status. Among men, institutionalized subjects were observed to have poorer thiamine and riboflavine status, in addition to the above findings. The greater prevalence of chronic diseases and disability in the convalescent unit and the private nursing home may partly account for the poorer nutritional status of residents in these two institutions.

Aged↗
PubMed1990

Plasma and erythrocyte zinc and birth weight in pre-eclamptic pregnancies.

Plasma and erythrocyte zinc concentrations in 45 proteinuric pre-eclamptic Chinese women were measured. There was no difference in either the plasma or erythrocyte zinc concentration between pre-eclamptic patients with and without intrauterine growth retardation. There was no correlation between either plasma or erythrocyte zinc concentration with the gestation at delivery, birth weight, mean arterial pressure and plasma albumin concentration. On the other hand, both plasma albumin concentration and mean arterial pressure were significantly correlated to birth weight, and the mean arterial pressure was also significantly higher in patients with intrauterine growth retardation. Plasma and erythrocyte zinc are not useful as indices of severity in pre-eclampsia.

Adult↗
PubMed1990

A comparison of biochemical indices of bone turnover in elderly institutionalized and free-living subjects.

Plasma concentrations of calcium-phosphate, alkaline phosphatase, 25-hydroxyvitamin D (25(OH)D) and albumin, and fasting urinary sodium/creatinine (Na/Cr), calcium/creatinine (Ca/Cr) and hydroxyproline/creatinine (HPr/Cr) were measured in a survey of 208 Chinese elderly subjects living in chronic care institutions, and compared with values from free-living elderly subjects. Plasma parathyroid hormone estimations were also performed on a subpopulation of women living in an institution. Subjects in institutions had higher urinary HPr/Cr ratios in both men and women, as well as higher urinary Ca/Cr ratios in women, suggesting increased bone resorption. These values show significant variation depending on the degree of mobility. Factors which could contribute to the increased bone loss among institutionalized subjects are: reduced physical activity, reduced exposure to sunlight and hence reduced plasma 25(OH)D concentrations, low calcium intake, protein calorie malnutrition and possibly higher sodium intake. Correction of these factors may reduce the risk of fractures among the elderly living in chronic care institutions.

Activities of Daily Living↗
PubMed1990

A longitudinal study of changes in erythrocyte zinc concentration in hyperemesis gravidarum.

Erythrocyte zinc concentration and plasma thyroid hormones were measured in 32 patients admitted to hospital because of hyperemesis gravidarum. At presentation, 8 patients had elevated total and free thyroxine concentrations. The initial erythrocyte zinc concentration in these 8 patients was not different from the others, but in 5 of them, a transient drop in the erythrocyte zinc concentration was observed 2-12 weeks later, and which returned to normal towards the end of pregnancy. The lowest erythrocyte zinc concentration in the hyperthyroxinaemic group (171.0 +/- 31.7 mumol/l of RBC) was significantly lower than that of the normothyroxinaemic group (214.2 +/- 33.9 mumol/l of RBC) (p less than 0.01). This indicates that hyperthyroxinaemia in patients with hyperemesis gravidarum represents true hyperthyroidism, but is different from classical thyrotoxicosis in that the elevation of thyroid hormones is transient.

Carbonic Anhydrases↗
PubMed1989

Plasma and erythrocyte zinc concentrations in pre-eclampsia.

Plasma and erythrocyte zinc concentrations were measured in 28 Chinese pre-eclamptic women and 28 controls matched for parity, race and gestation. There were no differences in either the plasma or erythrocyte zinc concentrations between pre-eclamptic and control groups, although the mean birth weight (p less than 0.001) and period of gestation (p less than 0.001) at delivery in the control group were significantly higher. In the pre-eclamptic patients, those delivering before 37 weeks or those who gave birth to low birth weight (less than 2500 g), babies had a significantly higher plasma urate concentration (p less than 0.02) compared to the pre-eclamptic patients with better fetal outcome. However, the plasma and erythrocyte zinc concentrations between these subgroups were not significantly different. Our results suggest that zinc deficiency is unlikely to play a significant role in pre-eclampsia in our patients, and that measurement of plasma and erythrocyte zinc concentrations is of doubtful clinical value in the management of pre-eclampsia.

Birth Weight↗
PubMed1989

Biochemical predictors of short term mortality in elderly residents of chronic care institutions.

A survey of 208 elderly subjects living in four long term care institutions was undertaken over three months to identify nutritional and other variables that could be used to predict mortality during the subsequent three months. There were 58 men (mean age (SD) 75.6 (9.6) years) and 150 women (79.5 (8.4) years). Twenty nine subjects died (12 men and 17 women) within three months of completing the study. Twenty eight out of 57 variables differed significantly between those who died and those who survived. Subjects who died had lower systolic blood pressure, poorer intake of protein calories, lower concentrations of haemoglobin, plasma retinol, zinc, total cholesterol, and higher albumin adjusted plasma calcium concentrations. Stepwise regression analysis identified five variables that predicted mortality: plasma fructosamine; transferrin; glycosylated haemoglobin; prealbumin; and haemoglobin. The sensitivity, specificity, and predictive values of the discriminant function score using 0 as the demarcation between survivors and non-survivors were 75%, 97%, and 95%, respectively. This score could therefore be used to identify those most in need of nutritional support.

Aged↗
PubMed1989

Thyroid function in hyperemesis gravidarum.

Plasma total T4 (TT4), T3 (TT3), free T4 (FT4), free T3 (FT3), thyroxine binding globulin, hCG, and erythrocyte zinc content were measured in 43 women with uncomplicated pregnancy and in 71 patients admitted with hyperemesis gravidarum. Plasma concentration of thyroid hormones in hyperemesis subjects showed wide variability and 32% of subjects had high TT4 (higher than mean +2 SD of normal pregnant subjects), 33% had high FT4, 20% had high TT3, and 20% had high FT3. Red cell zinc content, a tissue marker of thyroid status, in the hyperthyroxinemic subjects was not different from that of normothyroxinemic hyperemesis subjects or of subjects with uncomplicated pregnancy. The elevated TT4 concentration decreased spontaneously in all but two of the hyperemesis subjects to normal pregnant levels. The plasma FT4 concentration at presentation correlated with plasma hCG in hyperemesis gravidarum (partial correlation coefficient r = 0.411, P less than 0.01), but not in normal pregnancy (partial correlation coefficient r = 0.043) after allowing for the effect of gestational age. We conclude that approximately one third of hyperemesis subjects show transient hyperthyroxinemia and suggest that hCG or a molecular variant of hCG may stimulate the thyroid gland.

Adult↗
PubMed1989

Direct determination of lead in urine by flameless atomic absorption spectrophotometry with platform atomisation.

A direct method of urinary lead assay by flameless atomic absorption spectrophotometry is described for routine use in the clinical laboratory. It employs a simple sample pre-treatment procedure preceding automated analysis. Reproducibility, linearity and recovery were satisfactory without the need of standard addition. Mean and reference intervals of normal urine were similar to values reported in the literature.

Humans↗
PubMed1989

Plasma ferritin in an elderly population living in the community.

Plasma ferritin was measured in 420 apparently healthy active elderly subjects living in the community. Mean values were comparable to other published results for elderly subjects. Higher values were obtained in men and in diabetic subjects. Mean values for men and women after exclusion of subjects with diabetes and other diseases were not significantly lower. It is concluded that a) the age-related rise in plasma ferritin observed in other studies represents a physiologic change, with pathologic processes only playing a small part in contributing to the increase, b) reference intervals appropriate to the elderly should be used, and c) plasma ferritin may not be a useful screening test for iron deficiency anemia or hemochromatosis in the elderly.

Aged↗
PubMed1989

Some biochemical indices of bone turnover in elderly Chinese.

Biochemical indices of bone turnover were determined in a cluster sample of 427 apparently healthy elderly subjects aged 60 years and over. Plasma calcium concentrations corrected for albumin were not significantly different between elderly men and women, but were higher compared with values in younger Chinese of the same sex. The prevalence of hypercalcemia (greater than 2.75 mmol/L) in the elderly (0.2%) was lower than in Caucasian populations. Plasma phosphate concentrations were higher in women, but lower than in young adults. Plasma alkaline phosphatase activity was higher in women compared with values for men, and higher compared with values for young adults. Plasma 25-hydroxyvitamin D was lower in elderly women than elderly men, but was similar to values in younger subjects. Urinary calcium: creatinine and hydroxyproline: creatinine ratios were higher in women. The values were comparable to those for Caucasian postmenopausal women, suggesting that Chinese elderly subjects had similar bone turnover rates.

Adult↗
PubMed1988

Changes in erythrocyte and plasma zinc concentrations in pregnancy.

In a group of normal pregnant women, erythrocyte and plasma zinc concentrations were assessed at 8, 15, 25 and 35 weeks. Erythrocyte zinc concentration showed an increasing trend with a peak value at 25 weeks, although the increase did not reach a significant level. Plasma zinc concentration showed a significant decrease with the lowest value at 35 weeks. Erythrocyte and plasma zinc concentrations were not correlated, and there was no correlation between either of these concentrations and human chorionic gonadotrophin at 8-15 weeks. The value of zinc measurements in the management of complicated pregnancies is discussed.

Chorionic Gonadotropin↗
PubMed1988

Assessment of vitamin B1, B2 and B6 status by coenzyme activation of red cell enzymes using a centrifugal analyser.

We describe a fully automated method for the assessment of vitamin B1, B2 and B6 status using a centrifugal analyser. The activation of the red cell enzymes transketolase, glutathione reductase and aspartate aminotransferase) by their respective coenzymes were measured in freshly prepared haemolysate. The enzyme catalytic activities in the sample were measured with (maximal activity) and without (basal activity) the coenzyme, and the percentage activation was calculated. The between run precision for red cell transketolase, glutathione reductase and aspartate aminotransferase were 8.5%, 10.3% and 9.5% respectively. When whole blood was stored at room temperature for 6 hours, red cell aspartate aminotransferase activity significantly decreased (n = 10, p less than 0.05). There were no significant changes in the activities of the other two enzymes. For a group of 30 healthy young subjects, the mean (standard deviation) values for the percentage activation of transketolase, glutathione reductase and aspartate aminotransferase were 11.9% (7.3), 35.1% (19.1) and 85.3% (18.0), respectively. The vitamin status of a group of 86 pregnant women was assessed by this method; 2.3%, 8.1% and 8.1%, respectively, of the pregnant women showed a higher percentage activation for transketolase, glutathione reductase and aspartate aminotransferase than that found in the young subjects. Both groups correlated well with respect to the basal activity and the percentage activation of each enzyme. Basal activity was inversely proportional to the percentage activation. It is therefore suggested that the basal activity can be used as a second criterion in the assessment of vitamin status.

Adult↗