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Biomedical subjects

V C Wong

Publications and source records attributed to V C Wong.

At least 37 records · Page 2Linked to original sources
PubMed1987

Is treatment needed for mild impairment of glucose tolerance in pregnancy? A randomized controlled trial.

The study was designed to identify those pregnant women who are diagnosed as having gestational diabetes by National Diabetes Data Group (NDDG) criteria, but normal glucose tolerance (NGT) or impaired glucose tolerance (IGT) by the World Health Organization (WHO) criteria, and to test whether treatment changed the perinatal outcome in those with NGT and IGT. The 216 women with an abnormal 100 g oral glucose tolerance test (OGTT) using NDDG criteria were subjected to a 75 g OGTT. Using the WHO criteria, 111 women (51%) had NGT, 98 (45%) had IGT and 7 (3%) had frank diabetes mellitus. Those with NGT and IGT were randomized into control and treatment groups. The perinatal outcome in these two groups was comparable whether the NGT and IGT groups were analysed together or separately except, that in those who were treated for IGT, smaller babies were born one week earlier than in the control group (3407 g vs 3110 g, P less than 0.01). This suggests that the WHO criteria can safely replace the 100 g OGTT with substantial savings in manpower, money and patients' time.

Adult↗
PubMed1986

Blood pressure homeostasis in the snake, Ptyas korros.

Three putative pressor systems, the alpha-adrenergic system (AS), the renin angiotensin system (RAS), and the arginine vasotocin system (AVT-S), were studied for their roles in blood pressure regulation and their possible interactions in the rat snake. Ptyas korros. Norepinephrine (NE), angiotensin I (ANG I), and arginine vasotocin (AVT) increased the mean arterial pressure (MAP) of the snake while administration of phentolamine, an alpha-adrenergic antagonist, and captopril, an ANG-converting enzyme inhibitor, but not KBIV24, an AVT antagonist, decreased the MAP. Treatment with any combination of two of these antagonists/inhibitor invariably decreased the MAP. Treatment with the agonist of the remaining third system invariably returned the MAP to normal or above. Phentolamine and KBIV24 attenuated the vasopressor effect of ANG I. Phentolamine and captopril enhanced the vasopressor effect of AVT. The pressor effect of NE was not altered by KBIV24 and captopril. It was concluded that there were at least two pressor systems (AS and RAS) regulating the basal MAP in the snake. There was also interaction among the three systems which could affect the MAP.

Angiotensin I↗
PubMed1986

The mechanism of action of angiotensin II in the rat snake, Ptyas korros.

The hindquarter of the rat snake, Ptyas korros, was isolated for perfusion study in order to investigate the mechanism of action of angiotensin (ANG) II. Both ANG II and norepinephrine (NE) produced concentration-dependent increases in perfusion pressure. [Sar1, Ile8] ANG II significantly attenuated the response to ANG II but not that of NE. Phentolamine significantly reduced the responses to both ANG II and NE, with much greater inhibition on NE than ANG II. These findings suggest the presence of ANG II receptors and alpha-adrenergic receptors in the hindquarter. Since tyramine did not exert any increase in perfusion pressure, the release of ANG II-stimulated catecholamines was probably not involved in the increase in perfusion pressure to ANG II in the present preparation. The partial attenuation of the response to ANG II by phentolamine, therefore, suggests that ANG II may act directly on both specific ANG II receptors and alpha-adrenergic receptors.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1986

Comparative study on the cardiac actions of bovine parathyroid hormone (1-34).

The cardiac stimulatory effects of bovine parathyroid hormone (1-34) [bPTH-(1-34)] were studied on isolated atria and ventricular strips from cobra snakes (Naja naja), ducklings (Anas platyrhynchos), pigeons (Columba livia), Japanese quails (Coturnix coturnix japonica), laboratory rats (Rattus norvegicus), and dogs (Canis familiaris). In all atrial preparations, bPTH-(1-34) caused positive chronotropism. This suggests that the chronotropic effect of PTH is ubiquitous among the terrestrial vertebrates. Only the atria of cobra snakes and ducklings gave positive inotropic responses to PTH. No ventricular preparations showed significant response to bPTH-(1-34). This suggests the absence of cardiac stimulatory PTH receptors in the ventricles. Dog papillary muscle, however, showed slight but significant responses to bPTH-(1-34). The reason for this discrepancy between the responses of papillary muscles and the ventricular strips to PTH is unknown.

Animals↗
PubMed1986

Combined use of warfarin and adjusted subcutaneous heparin during pregnancy in patients with an artificial heart valve.

Adjusted subcutaneous heparin was used for thromboembolism prophylaxis during 18 pregnancies in 16 women with an artificial heart valve. Oral warfarin was replaced by subcutaneous heparin as soon as pregnancy was confirmed. The dosage of heparin was adjusted to maintain a partial thromboplastin time at 1.5 times the control value and treatment was administered during the first trimester and the last 3 weeks of gestation. Warfarin was used between the 13th and 37th week. There were no maternal thromboembolic complications and none of the live-born infants showed congenital malformations, indicating that this regimen is effective. However, there were nine spontaneous abortions, including five that occurred in the first 12 weeks. The early abortions were probably related to warfarin exposure at the beginning of pregnancy. The preconception replacement of warfarin by heparin in these patients may be indicated.

Abortion, Spontaneous↗
PubMed1985

Pregnancy in patients with mitral valve prolapse.

The obstetrical performances and outcomes of 37 pregnancies in women with mitral valve prolapse between 1979 and 1982 are reviewed. Thirteen patients were diagnosed before pregnancy and 24 patients were detected at antenatal examinations. Three ended in cesarean sections for obstetrical complications and 34 in uneventful vaginal deliveries at term. No cardiac complications occurred in these patients. There was no maternal mortality. Thirty-six babies were born without congenital abnormalities. One baby was hydropic due to haemoglobinopathy and died. Prophylactic antibiotics is recommended in selected cases. Early detection and treatment of cardiac arrhythmias is mandatory.

Adult↗
PubMed1985

Intrauterine death from ergotamine overdosage.

Fetal death in a primigravid patient who had taken an overdose of ergotamine tartrate is presented. Non-stress cardiotocography performed shortly after admission was technically unsatisfactory for interpretation but revealed the presence of very frequent uterine contractions. The cause of fetal death in this patient is discussed. Overdosage of ergotamine must be considered a serious threat to the well-being of the fetus in utero.

Adolescent↗
PubMed1985

Homozygous alpha-thalassaemia: clinical presentation, diagnosis and management. A review of 46 cases.

Forty-six hydropic infants with homozygous alpha-thalassaemia born during a period of 10 years have been reviewed. The incidence was 1:1550 total births, and accounted for 81% of all non-immune hydrops. The male to female ratio was 1:1.4. There was increased incidence of anaemia, pregnancy induced hypertension, antepartum haemorrhage, malpresentation, prematurity, fetal distress, difficult vaginal delivery, caesarean section, retained placenta, postpartum haemorrhage and congenital abnormalities. Antenatal diagnosis by DNA hybridization with subsequent abortion of the affected fetuses is the best method to decrease maternal morbidity and to reduce the incidence of hydrops fetalis in couples at risk. For those with no previous history, but with early onset hypertension and/or polyhydramnios, sonography is useful in making an earlier diagnosis, and in reducing avoidable morbidity, because DNA analysis can be done before caesarean section and aggressive neonatal management is instituted.

Adolescent↗
PubMed1985

Estimation of fetal weight in utero from symphysis-fundal height and abdominal girth measurements.

The ability to estimate fetal weight accurately from symphysis-fundal height (SFH) and abdominal girth (AG) measurements was evaluated. Multivariate regression analysis was performed on measurements made on 208 primigravidas within 48 hours of delivery. A better correlation with birth-weight was obtained with the SFH than with the AG. The equation BW = -1.515 + 0.092 (SFH) + 0.016 (AG) yielded a coefficient of multiple correlation of 0.7259. Using this equation, the mean percentage prediction errors were 5.7% +/- 4.2(SD) in fetuses between 2,500 and 3,500 g (n = 156), 9.4% +/- 5.25(SD) in those larger than 3,500 g (n = 33), and 19.1% +/- 8.2(SD) in those smaller than 2,500 g (n = 19). All the generated equations similarly underestimated the fetal weight in the larger babies and overestimated in the smaller babies. Inclusion of quadratic and logarithmic functions as well as skin-fold thickness measurements into the equations did not decrease the error or alter the distribution of errors. It was concluded that although fetal weight estimation may be reasonably accurate between 2,500 g and 3,500 g, the error is too great for the method to be clinically useful in the smaller and larger babies. Moreover, a theoretical basis for a high sensitivity in the detection of small for dates fetuses from these parameters would be difficult to establish.

Birth Weight↗
PubMed1985

Dextropreponderance of corpus luteum rupture. A clinical study.

A retrospective study of 55 consecutive patients with cystic corpora lutea, corpus luteum cysts or hematomas was undertaken to verify the observation of a right-side predominance in the incidence of rupture. Thirty-nine patients had a ruptured corpus luteum diagnosed surgically and confirmed histologically. No difference was observed in the overall distribution, the volume of hemorrhage or the size of the cysts between the two sides. A statistically significantly higher incidence of rupture was found on the right side (81.25%) as compared to the left (56.52%). We propose a working hypothesis of a difference in the ovarian venous architecture that causes a higher intraluminal pressure in the right corpus luteum and the dextropreponderance of ruptures.

Adolescent↗
PubMed1984

Prevention of the HBsAg carrier state in newborn infants of mothers who are chronic carriers of HBsAg and HBeAg by administration of hepatitis-B vaccine and hepatitis-B immunoglobulin. Double-blind randomised placebo-controlled study.

Newborn infants of Chinese HBeAg-carrier mothers in Hong Kong were randomly assigned to one of four study groups. Group I was treated with 3 micrograms heat-inactivated hepatitis B (HB) vaccine at birth and at 1, 2, and 6 months thereafter, in conjunction with seven monthly HBIg injections; group II was treated according to the same vaccine schedule but received only one HBIg injection at birth; group III received only the vaccine, at months 0, 1, 2, and 6; and group IV received placebos for both vaccine and HBIg. The first set of injections was given within 1 h after birth. Comparisons were made in the 140 children who were at least six months old at the close of the trial (495 days). In all three treatment groups development of the persistent carrier state was significantly (p less than or equal to 0.0001) less frequent than in controls (2.9%, 6.8%, and 21.0% versus 73.2%). Although vaccination alone was significantly less protective than vaccination plus multiple HBIg injections (p = 0.03), the degree of protection was still remarkable. 12 months after the first set of injections 96-100% of the infants in the three treatment groups were anti-HBs positive; the geometric mean titres of anti-HBs in the three groups did not differ significantly. This indicates that even high doses of HBIg do not interfere with the anti-HBs response to the vaccine. Probable intra-uterine HB infections were observed in 3 infants. No serious side-effects were observed from the interventions, even in the babies with intra-uterine infections who had received HBIg and HB-vaccine at birth. To prevent development of the persistent HBsAg carrier state, and thereby the consequent chronic liver disease and/or primary carcinoma of the liver, HB vaccine and HBIg should be administered as soon as possible after birth to all newborn infants at risk of perinatal hepatitis B infection.

Carrier State↗
PubMed1984

Blood pressure homeostasis in Rana catesbeiana under normal and hypovolemic conditions.

The effects of phentolamine, KBIV24 and captopril on the mean arterial blood pressure of normal and treated (dehydration, hemorrhage) frogs were determined. Hemorrhage but not dehydration led to a decrease in MAP. Only phentolamine attentuated MAP in both normal and treated frogs. KBIV24 and captopril were ineffective. It was concluded that the blood pressure of frogs is regulated by catecholamine. Neither arginine vasotocin nor the renin-angiotensin system play any role in blood pressure homeostasis in normal and hypovolemic conditions.

Animals↗