Serum stem cell factor levels in patients with aplastic anemia

Immune suppression of hematopoiesis has been implicated in the pathogenesis of acquired aplastic anemia. Similarly, abnormalities of T cells and bone marrow stromal cells have been reported in aplastic anemia, as has abnormal cytokine production. Stem cell factor (SCF) (also known as kit ligand, mast cell growth factor and Steel factor) is an early acting hematopoietic growth factor that is produced by a variety of mesenchymal cells including bone marrow stromal cells. To determine whether abnormalities in the production of stem cell factor occur in aplastic anemia, we evaluated serum levels of SCF in 25 patients with aplastic anemia. The mean serum levels of SCF in aplastic anemia patients were significantly lower (2.7 +/- 1.1 ng/ml) than those found in a comparable population of 257 normal controls (3.3 +/- 1.1 ng/ml) (P = 0.011). The SCF level did not correlate with patient age, the duration of aplastic anemia or with white blood cell count, platelet count or hematocrit. Although there is no direct evidence that lower SCF serum levels contribute to the pancytopenia seen in this disorder, identification of underlying abnormalities that can result in the deficient production of stromally derived hematopoietic growth factors will be important.

Dietary calcium intake in postmenopausal Chinese women

Dietary calcium intake has been shown to vary both between and within populations. The aim of this study was to compare two methods of assessment of dietary calcium in the local population of postmenopausal Chinese women. The intake was measured using 24h dietary recall as well as a food frequency questionnaire. There was a high correlation in the measurement of calcium intake between these methods. The mean daily intake in postmenopausal women not taking calcium supplementation was 397.6 mg assessed using 24 h recall, and 390.9 mg according to the food frequency questionnaire. There was no evidence of a difference in the reproducibility of the results given by the two methods. The dietary intake of calcium in postmenopausal Chinese women is below the recommended daily allowance for adult females in East Asia, and coupled with other factors may predispose to the development of osteoporotic fractures.

The effects of enalapril and nifedipine on carbohydrate and lipid metabolism in NIDDM

OBJECTIVE

To compare the effects of nifedipine and enalapril on carbohydrate and lipoprotein metabolism in Chinese non-insulin-dependent diabetes mellitus (NIDDM) patients with hypertension.

RESEARCH DESIGN AND METHODS

A 12-week, double-blind, randomized study of plasma lipid levels and glycemic control in patients treated with nifedipine (n = 52) or enalapril (n = 50) was conducted. None of the patients were treated with insulin. Diet and dosages of oral hypoglycemic agents remained unchanged during the 12-week treatment period.

RESULTS

Mean arterial pressure was reduced more by nifedipine than by enalapril (23.1 vs. 11.1 mmHg, P < 0.001). Similar reductions in body mass index and plasma triglycerides and increases in apolipoprotein A-I were seen with both treatments, but HbA1 was reduced more during treatment with enalapril than with nifedipine (0.49 vs. 0.20%, P = 0.035) and serum apolipoprotein B (apoB) also declined more with enalapril than with nifedipine (8.2 vs. 2.3 mg/dl, P = 0.009).

CONCLUSIONS

Twelve weeks of treatment with enalapril in hypertensive NIDDM patients was associated with greater improvement in glycemic control and greater reduction in serum apoB concentration, although the reduction in blood pressure was less than with nifedipine. These changes in cardiovascular risk profile warrant investigation for a longer term.

Recovery after propofol infusion anaesthesia in children: comparison with propofol, thiopentone or halothane induction followed by halothane maintenance

We have compared the recovery profiles of 163 healthy Chinese children after general anaesthesia for minor surgical procedures. Patients were allocated randomly to receive one of four anaesthetic techniques: propofol infusion for induction and maintenance using a pharmacokinetic model-controlled syringe pump set initially at a target concentration of 8 micrograms ml-1 and then adjusted according to clinical requirements; propofol 2.5-3.5 mg kg-1, thiopentone 4-5 mg kg-1 or 2-3% halothane for induction of anaesthesia followed by 1-2% halothane for maintenance of anaesthesia. All patients breathed a mixture of 70% nitrous oxide in oxygen through a laryngeal mask airway and received an appropriate regional anaesthetic block. Recovery was assessed using the time to achieve full Steward score, open eyes on command, orientation and the time required to complete a simple puzzle. Recovery was slowest with the propofol infusion (mean 39.8 (SD 12.9) min when eyes opened on command). The recovery times were significantly shorter with the three other techniques (propofol bolus 21.9 (9.9) min, thiopentone 23.4 (11.3) min, halothane 20.1 (8.9) min), and the choice among these three methods had no significant influence on the recovery profile.

A prospective study of the frequency of acute menopausal symptoms in Hong Kong Chinese women

A prospective study was conducted amongst Hong Kong Chinese women to determine the incidence of acute menopausal symptoms following surgical menopause. Cases where a laparotomy was performed for other indications were used as controls. Hot flushes and sweating developed in 8/33 (24.2%) and 6/33 (18.2%), respectively, of those women having had a total abdominal hysterectomy and bilateral salpingo-oophorectomy. Whilst vasomotor symptoms were more frequent in those women who had undergone a surgical menopause than in the controls, women in this population were shown to suffer fewer symptoms than has been demonstrated in Caucasian women. Although this study does not help to explain why such differences exist, the relative absence of symptoms may contribute to the low demand for hormone replacement therapy in Hong Kong and other countries where climacteric symptoms are relatively infrequent.

Binding of atrial and brain natriuretic peptides to cultured mouse astrocytes from different brain regions and effect on cyclic GMP production

We prepared primary cultures of mouse astrocytes from the cerebral cortex, hypothalamus, and cerebellum to examine the possibility of regional disparity in binding of human atrial and porcine brain natriuretic peptides (hANP, pBNP) and their effect on cyclic guanosine monophosphate (cGMP) production. 125I-hANP and 125I-pBNP bound in a specific and saturable manner to all three regions. For both peptides, Scatchard analysis suggested a single population of binding sites on astrocytes from all three regions. No significant differences were observed in the maximal binding capacities (Bmax) or binding dissociation constants (KD) between the two peptides in the astrocyte preparations from different regions. ANP and BNP also evoked cGMP stimulation in a similar, dose-dependent fashion in astrocytes from all three regions, with maximal responses to both peptides reached at a concentration above 1 microM. While BNP elicited a greater maximal cGMP accumulation than ANP, no difference could be demonstrated in the cGMP responses to either peptide between brain regions. Thus we have been unable to demonstrate regional heterogeneity in the responsiveness of astrocytes to ANP and BNP.

Minimum alveolar concentration of halothane: an ethnic comparison

The minimum alveolar concentration (estimate of spread) of halothane which was determined in 42 Chinese, Nepalese or European patients was found to be 0.70% (0.66-0.74%) in Chinese and 0.70% (0.65-0.76%) in Nepalese and 0.68% (0.65-0.72%) in Europeans, using the Spearman Kärber method of analysis. This preliminary trial suggests that there is no ethnic difference in the minimum alveolar concentration of halothane between Asians and Europeans.

Biotransformation of pethidine: a comparative study of 24 h urine in three ethnic groups

219 surgical patients of either Caucasian, Chinese or Nepalese origin were given pethidine 1 mg/kg by intramuscular injection as pre-operative medication. Urine was collected for 24 h and analysed for pethidine, pethidinic acid, pethidinic acid conjugates, norpethidine, norpethidinic acid, and norpethidinic acid conjugates. The mean proportion of the percentage of metabolites attributable to oxidative demethylation, hydrolysis and conjugation was almost identical in each ethic group (P > 0.2). It was concluded that there were no differences in the metabolic variability of the biotransformation of pethidine in Asians and Caucasians in whom the urine pH had not been acidified.

A clinical evaluation of the Hemocue haemoglobinometer using capillary, venous and arterial samples

The 'Hemocue' device for rapid estimation of haemoglobin concentration was evaluated in a clinical setting. Repeatable accuracy of capillary, venous and arterial samples was examined and then compared with standard laboratory venous haemoglobin estimates using a 'Coulter JT' analyser in 42 patients. The mean values for haemoglobin (g/l) and coefficient of variation were capillary 108.2 (8.0); venous 104.9 (2.2); arterial 105.9 (2.0); and laboratory venous 104.6 (1.3). Although the mean haemoglobin values were similar, capillary samples were significantly less repeatable than venous or arterial samples (Pitman test, P < 0.001). Comparison of variance between the laboratory sample and each sampling technique demonstrated that capillary samples were significantly more variable than venous or arterial samples. Peripheral skin temperature did not influence the accuracy of capillary samples. Hemocue estimations of venous samples were found to be as accurate as laboratory estimations. The lack of repeatable accuracy of capillary estimations was sufficiently large that their use cannot be recommended in clinical practice.

Induction dose-response of propofol in unpremedicated children

The induction dose requirements of propofol were compared in three age groups in 300 unpremedicated healthy Chinese children: group A, younger than 2 yr (n = 48); group B, 2-5 yr (n = 117); group C, 6-12 yr (n = 135). Patients in each group were allocated randomly to receive one of eight doses of propofol (1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4 and 2.6 mg kg-1). ED50 and ED95 for loss of eyelash reflex (LER) and acceptance of face mask (AFM) were determined using probit analysis. ED50 and ED95 for both LER and AFM were greatest in group A, less in B and smallest in C; ED95 (AFM) for groups A, B and C were 2.88 (2.55-3.36), 2.53 (2.31-2.86), and 2.20 (2.02-2.46) mg kg-1, respectively. This probably represented their effective induction dose. The incidence of apnoea was dose related, but not pain on injection.

Neonatal outcome and its relationship with maternal age

The relationship between maternal age and neonatal outcome was examined in 22,689 pregnancies using various determinants of neonatal well-being which included evidence of fetal distress, birth-weight, Apgar scores, the necessity for admission to the neonatal unit and other indicators of neonatal morbidity. Differences in the incidence of congenital malformations and perinatal mortality were also studied. There was a trend towards more frequent fetal heart monitoring, lower birth-weight and a higher rate of neonatal unit admission for infants delivered by younger women. There was also a significant increase in the Caesarean section rate with advancing maternal age. Maternal age had no effect, however, on the incidence of fetal distress, Apgar score, the development of respiratory disease, the need for intubation and ventilation nor on subsequent neonatal central nervous system complications. There was also no association between maternal age and either perinatal mortality or the incidence of congenital malformations. The favourable outcome in teenagers in this study may have been influenced by the extremely low pregnancy rate amongst young adolescents in Hong Kong, but a similar outcome in the mature age women was likely to have reflected the recognition of risk and its appropriate management.