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Biomedical subjects

T Y Khong

Publications and source records attributed to T Y Khong.

At least 19 recordsLinked to original sources
PubMed1998

Pregnancies complicated by retained placenta: sex ratio and relation to pre-eclampsia.

Pre-eclampsia and placenta accreta have opposite histological features of placentation. This study set out to test the hypotheses that the sex ratios in these two pregnancy complications are opposite and that these conditions are mutually exclusive. A population-based database covering all deliveries in South Australia between 1986 and 1995 and the hospital-based obstetric database of the Adelaide Women's and Children's Hospital, covering 8549 births between 1993 and 1995, were used to ascertain the sex ratios in singleton pregnancies and the sex ratios in those pregnancies in which there was retained placenta, hypertension in pregnancy, or pre-eclampsia. The likelihood of independence of occurrence or mutual exclusivity of retained placenta and hypertension in pregnancy or pre-eclampsia were also examined. The male:female sex ratio in the South Australian population was 1.077. In pregnancies with hypertension in pregnancy it was 1.165 (P<0.001) and in pregnancies with retained placenta it was 0.883 (P<0.0001). There was a trend to an increased sex ratio in pre-eclamptic pregnancy (1.248 in primigravid and 1.092 in multigravid women) but there was insufficient power to detect significance (P=0.207 and 0.470, respectively). Neither hypertension in pregnancy nor pre-eclampsia were mutually exclusive of placenta accreta: hypertensive disorders of pregnancy and placenta accreta occurred independently of each other. Our findings suggest that sex-linked antigens are unlikely to influence maternofetal interactions consistently to give rise to one but not the other pregnancy complication.

Adult↗
PubMed1998

Expression of endothelin-1 in amniotic fluid embolism and possible pathophysiological mechanism.

Since endothelin is a potent vasoconstrictor and bronchoconstrictor, endothelin-1 expression in the lung was investigated using immunohistological techniques in two cases of amniotic fluid embolism. Intense expression of endothelin-1 was observed in amniotic squames while weaker staining was seen in alveolar epithelium, bronchiolar epithelium and intraalveolar macrophages and focally in vascular endothelium. Endothelin-1 may play a role in the early and transient haemodynamic alteration of pulmonary hypertension in amniotic fluid embolism.

Embolism, Amniotic Fluid↗
PubMed1997

First-trimester diagnosis of Smith-Lemli-Opitz syndrome.

We report here the prenatal diagnosis of Smith-Lemli-Opitz (SLO) syndrome in the first trimester by direct measurement of 7-dehydrocholesterol (7-DHC) in a chorionic villus (CV) biopsy. The proband was diagnosed clinically at birth and the diagnosis was confirmed biochemically by demonstrating elevated 7-DHC in plasma. The family pursued prenatal diagnosis in their fourth, fifth, and sixth pregnancies. The fourth pregnancy spontaneously miscarried at 9 weeks' gestation. Analysis in both direct and cultured curetting tissue (identified as similar to CV tissue) showed an abnormal tissue neutral sterol pattern with an elevated 7-DHC concentration. The fifth pregnancy also miscarried spontaneously at 9 weeks but no tissue of unequivocal fetal origin could be identified to allow biochemical investigation. In the sixth pregnancy, ultrasound examination at the time of CV sampling showed a thickened nuchal fold. Direct analysis of the CV sample revealed elevated levels of 7-DHC consistent with the diagnosis of SLO. The pregnancy was terminated and both fetal tissue and cultured fetal cells showed marked increases in 7-DHC, confirming the prenatal diagnosis.

Cells, Cultured↗
PubMed1997

Idiopathic focal foveolar hyperplasia in infants.

Idiopathic focal foveolar hyperplasia (FFH) is a rare cause of gastric outlet obstruction in infants. We present two cases, including the first reported association with infantile hypertrophic pyloric stenosis. The diagnostic ultrasound appearance of FFH is described. Optimal treatment is surgical excision of the involved mucosa with pyloroplasty or pyloromyotomy.

Diagnosis, Differential↗
PubMed1997

Lack of correlation between conceptual karyotype and maternal response to placentation.

The placental karyotype was correlated with the morphology of the placental bed in miscarriages. Abnormal placentation was as likely to be seen in euploid conceptions as in aneuploid conceptions, whereas normal placentation was seen with both euploid and aneuploid pregnancies. No consistent chromosomal abnormality was found with abnormal placentation. Since abnormal placentation is implicated in the pathogenesis of preeclampsia and miscarriages, these findings may be useful with respect to the localization of a candidate 'preeclampsia gene' by identifying a specific chromosome associated with abnormal placentation.

Abortion, Spontaneous↗
PubMed1997

Bcl-2 expression delays postpartum involution of pregnancy-induced vascular changes in the human placental bed.

In subinvolution of the placental bed, the uteroplacental (spiral) arteries that had undergone physiologic changes to accommodate the needs of the placenta and fetus during pregnancy fail to involute and avert to their nonpregnant state. Because expression of bcl-2 oncoprotein is associated with inhibition of apoptosis and prolonged cell survival, we examined its expression in third-trimester human placental bed tissue and in uterine tissue from women presenting with postpartum hemorrhage in which a diagnosis of involution or of subinvolution of the placental bed was made. bcl-2 oncoprotein was not detected in the uteroplacental arteries during the third trimester of pregnancy but was seen in involution and, more strongly, in subinvolution of the placental bed. Extravillous trophoblast was weakly stained in pregnancy and in the postpartum specimens, whereas glandular epithelium was stained to a variable degree and intensity. The findings suggest that involution and subinvolution of the placental bed are morphologic entities that lie in the spectrum between complete resolution and noninvolution of pregnancy-induced changes and that bcl-2 is associated with subinvolution of the uteroplacental arteries.

Arteries↗
PubMed1997

From delivery suite to laboratory: optimizing returns from placental examination in medico-legal defence.

While examinations of the placenta may reveal significant lesions that are helpful in a medico-legal context, its value maybe diminished by a lack of attention to detail in the period between delivery of the baby and receipt of the placenta in the pathology department. These fall generally into 2 groups: initial description and handling of the placenta and lack of relevant clinical information. This communication describes some of these pitfalls. By observing these details, the onus then falls on the pathologist to provide a meaningful assessment of the placenta.

Australia↗
PubMed1997

Improving perinatal autopsy rates: who is counseling bereaved parents for autopsy consent?

BACKGROUND: Concern has been expressed recently about perinatal autopsy rates, which are often below recommended levels. Since a possible reason for the decline in adult autopsy rates is the person seeking permission for autopsy, a study was undertaken to ascertain who were seeking consent and who offered counseling for perinatal postmortem examinations. METHODS: A postal questionnaire survey of members of a support group, Stillbirths and Neonatal Death Society in South Australia, was conducted. RESULTS: The idea for an autopsy was initiated by a physician in 20 of 46 cases and by junior medical doctors, midwives, nurses, or social workers in 22 of 46. Women had further counseling and discussion with physicians in 22 cases, junior medical staff in 10, midwives or nurses in 20, social worker in 9, and support group member in 1. Only 33 of the 46 women thought that they had been counseled about the advantages of the autopsy. CONCLUSIONS: It is important that all health workers involved in counseling the bereaved mother know of the benefits and the mechanics of an autopsy so that consent or refusal is based on informed counseling.

Adult↗
PubMed1997

Absence of innervation of the uteroplacental arteries in normal and abnormal human pregnancies.

The spiral arteries of the human uterus are considerably remodeled structurally during pregnancy to facilitate an increase in blood flow. An immunohistochemical study was undertaken to determine whether the spiral arteries were innervated and, if so, whether they were denervated in the process of the physiologic vascular changes of normal pregnancy or, conversely, remained innervated in the absence of physiologic changes in abnormal pregnancy. Uterine tissues from nonpregnant nulliparous women, from normal early pregnancy, from normal late pregnancy, from abnormal early pregnancy (i.e. spontaneous abortions), and from abnormal late pregnancy (i.e. preeclampsia and intrauterine growth retardation) were subjected to immunohistochemistry using a panel of neuron-associated antibodies (neurofilament, neuron-specific enolase, S100 protein, protein gene product 9.5). All sections of the nonpregnant uterus showed an abundance of nerves deep in the myometrium, some of which were associated with radial and arcuate arteries. Very few nerves were demonstrated at the endomyometrial junction and no nerves were seen accompanying the intramyometrial spiral arteries. In both normal and abnormal pregnancy, nerves were not detected in the decidua or accompanying intradecidual spiral arteries, whether they were physiologically altered or not. Nerves were seen in the myometrium in 7 of 10 normal and in 1 of the 8 third-trimester abnormal placental beds, but none were seen accompanying intramyometrial spiral arteries, whether showing physiological changes or not. The lack of innervation of the spiral arteries in the nonpregnant state as well as in normal and abnormal pregnancy suggests that nonneurogenic mechanisms control blood flow at the spiral-arterial level.

Abortion, Spontaneous↗
PubMed1997

Myths, misconceptions and the autopsy.

Although examination of the dead to determine why a death occurred has probably been undertaken from the earliest times, formal investigation by a qualified specialist medical practitioner is a much more recent phenomenon. Unfortunately a number of misapprehensions and myths concerning the role and process of autopsy examination exist. While autopsies are not all that common, most medical practitioners have been faced with the onerous task of explaining to relatives what happens to the body during and after an autopsy. The following paper deals with some of the concerns that are periodically raised by non pathologist physicians and health care workers who are involved with grieving relatives. The text is aimed at health care workers and is not in an appropriate format for relatives.

Autopsy↗
PubMed1996

Accidental infant death and stroller-prams.

A three-month-old boy and an eight-month-old boy died from accidental positional asphyxia and hanging, respectively, after being placed to sleep unsupervised in stroller-prams. Both infants had moved down towards the fronts of the stroller-prams. The younger infant fell out when the footplate collapsed and he was found hanging from a metal bar on the side. The older infant had partly slipped through the front and was suspended with his head and arms within the stroller-pram and with his face pushed firmly into the mattress by a horizontal metal bar. Stroller-prams are a potentially dangerous sleeping environment unless infants are closely supervised, gaps in the front of stroller-prams closed and upright footplates stabilised.

Airway Obstruction↗
PubMed1996

A review of perinatal autopsy rates worldwide, 1960s to 1990s.

Epidemiological data derived from death certification in the absence of a necropsy can be erroneous. Despite concern over adult hospital necropsy rates, which have fallen dramatically in the last 40 years, relatively less has been published regarding perinatal necropsy rates. A literature review of necropsy rates for neonatal deaths, stillbirths and perinatal losses was undertaken. There is a wide variation in the perinatal necropsy rates worldwide but the numbers appear to be higher than adult hospital rates. The necropsy rate for neonatal deaths appears to be lower than that for stillbirths. It is hoped that the review will serve to alert readers to remain vigilant against any fall in the perinatal necropsy rates.

Autopsy↗
PubMed1996

An audit of hysterectomies in young women at the Queen Victoria Hospital, 1984-1994.

A retrospective audit of hysterectomies in young women (age 30 years and under) was conducted. Forty-one hysterectomies, representing 4% of all hysterectomies at the hospital, were performed in women of this age group. The main clinical indications were abnormal uterine bleeding (44%), pelvic pain (20%) and endometriosis (15%). None were performed for invasive malignant conditions. Most women had some prior therapy for their symptoms. Thirty-seven of the operations were total abdominal hysterectomies and 4 women had a unilateral oophorectomy. Complications were found in 17 women. Causal pathology, though not always what was predicted clinically or on the basis of operative findings, was identified. Further studies would be worthwhile to document the experience from other institutions and to provide long-term follow-up.

Adult↗
PubMed1996

Ethical considerations of the perinatal necropsy.

The perinatal necropsy is an important investigation following fetal or neonatal loss. Legal requirements on registration decree that consent is needed before necropsy can proceed in some of these babies. However, there are ill-defined grey areas which are open to legal and ethical difficulties. This paper discusses the problems that can arise with consent for a necropsy in the perinatal period. Some of these problems are clearly legal or ethical but all can cause distress to parents at a time of grief and bereavement. The issues may not be readily resolved but public debate and ad hominem decisions on each perinatal loss may help to alleviate the problems.

Aborted Fetus↗
PubMed1996

Subinvolution of the placental bed after molar pregnancy.

OBJECTIVE: To describe the occurrence of subinvolution of the placental bed following molar pregnancy. STUDY DESIGN: A review of archival histology and clinical charts. RESULTS: Four cases of subinvolution of the placental bed after a molar pregnancy were found in an institutional review; three were preceded by a complete mole and one by a partial mole. In all four cases the arteries were widely distended and mainly devoid of thrombus formation. Plentiful persistent interstitial trophoblast was seen within the decidua and myometrium, and endovascular trophoblast was seen embedded within the arterial walls in all four and intraluminally in two of the cases. CONCLUSION: The condition may be underdiagnosed after molar pregnancy and is a likely cause of continued bleeding following evacuation of the hydatidiform mole.

Adult↗