No description available.

No description available.

No description available.

21-hydroxylase deficiency is the commonest enzyme defect in congenital adrenal hyperplasia resulting in low circulating cortisol and, in severe cases, low aldosterone which may lead to cardiac arrest in the neonate. As the low levels of coitisol· lead to raised levels of adrenocorticotrophic hormone large concentrations of androgens are formed in utero which may lead to cliteromegaly and consequent confusion of the sexes at birth. High concentrations of the androgens give rise to rapid growth in early childhood and early fusion of the epiphyses results in short stature of the adult. 17-alphahydroxyprogesterone (170HP) is raised in the blood and saliva of children with 21-hydroxylase deficiency. 170HP is commonly measured by radioimmunoassay which limits the assay to being performed by laboratories equipped with beta or gamma counters. The aim of this project was to develop an enzymeimmunoassay which could be carried out using the minimum amount of equipment. Horseradish peroxidase was conjugated to 170HP-O-carboxymethyloxime using a mixed anhydride reaction. Separation of free and bound label was achieved using a second antibody linked to magnetisable particle solid phase. Measurement of the bound enzyme activity yielded colours which could be compared by eye, with known standards, to give a semi-quantitative assay. Alternatively the absorbance could be measured using a spectrophotometer for full quantitative results. The developed assays were evaluated, comparing the results with radioimmunoassay, and then used for measuring 170HP in blood and saliva in various clinical situations.

Congenital Heart Defects (CHDs), structural heart defects that are present at birth, are prevalent in approximately 1% of live births. While, historically, the presence of such defects was associated with a heightened risk of mortality, advances in medicine have allowed nearly 85% of individuals with CHDs to live into adulthood. As such, many of these individuals are reaching reproductive age and are becoming pregnant. In order to understand the implications of pregnancy among women with CHDs, a literature review was undertaken in order to elucidate the conditions that may present to the mother, as a product of the underlying defect, as well as to discern the impact of a maternal CHD on the child. Pregnancy induces hemodynamic alterations, such as an increase in stroke volume and heart rate (and thus cardiac output), and brings about an increase in blood volume. In populations with CHD, these hemodynamic changes may induce particular risks to the mother, as her cardiac condition may obstruct her ability to cope to with the heightened stress on the heart. Moreover, given that the heart may not function in an ideal manner, a less than ideal environment is present in-utero. Women with CHD suffer from elevated cardiovascular and obstetric complications, with the risk of some cardiovascular events extending into the post-partum period. During pregnancy, approximately 11% of women with CHD will experience a cardiovascular complication; this risk is highest among those with complex forms of the defect. Arrhythmia, specifically, is the most common complication, and will occur in 4.5% of pregnancies. Heart failure is also frequent, occurring in 4% to 5% of pregnancies, with the highest risk presenting in those patients with Eisenmenger syndrome and those with cyanotic forms of CHD. Pulmonary edema and thrombolytic events are also present in this population with a higher prevalence than in a healthy pregnant population. In the 6-month period after delivery, 12% of women with CHD will experience a cardiac event, with arrhythmia and heart failure as the most common complications. Obstetric complications occur in approximately 5% of pregnancies among women with CHDs, with 11% experiencing premature labor, 8.4% experiencing post-partum hemorrhage and 5.5% experiencing pregnancy-induced hypertension. Miscarriage occurs in 15% of pregnancies, with a dose-response type relationship associated with the severity of the underlying defect, as miscarriage occurs in up to 66% of pregnancies in those with Fontan palliation. Premature rupture of membranes occurs in 3.5% of pregnancies, with half of these cases occurring to patients with transposition of the great arteries. Termination of pregnancy also occurs in 5% to 8% of pregnancies, given high risk of complications to both mother and fetus. While preeclampsia is expected to occur in approximately 2-3% of pregnancies, this risk does not exceed what occurs in a healthy population. With regard to the impact of maternal CHD on the fetus, events occurring to the fetus/neonate include preterm delivery, small for gestational age, respiratory distress syndrome, intraventricular hemorrhage, and neonatal death. Between 1.5% and 2% of pregnancies will terminate in fetal mortality. Premature birth is likely in 12% to 20% births, with of 8% of neonates born as small for gestational age. Moreover, 3.5% of children born to mothers with CHD will present with CHD, themselves. Long-term effects of maternal CHD are not well-described. Despite these complications, pregnancy among women with CHD is well-tolerated and only in very few cases of those presenting with severe defects, is pregnancy counter-indicated. However, in order to mitigate risks, pre-pregnancy counseling is recommended in all women with CHD, regardless of severity of the defect. Counseling should include an overview of the form of defect, any surgical or medicinal interventions undertaken in response to the defect, an echocardiography, an exercise stress test, among other evaluations. Monitoring of the pregnancy should continue throughout gestation and delivery should occur in a specialized care facility and the mother and fetus should be monitored by a consortium of cardiologists, obstetricians, anesthesiologists, midwives. Monitoring of the mother should extend into the post-partum period until any cardiovascular or hemodynamic pregnancy-related alterations have returned to normal.

Thesis (M.S.)--Boston University

Thesis (M.D.)--Boston University

A ventricular septal defect occurring on its own is a congenital defect of the interventricular septum of the heart causing varying degrees of increased pulmonary blood flow and associated clinical symptoms. It may also occur in association with obstruction in the right ventricle resulting in diminished pulmonary blood flow. Very little is documented about the incidence of ventricular septal defects in South African children. The aim of this study was to briefly review the embryology and consider the normal anatomy of the interventricular septum. In addition, the clinical and surgical notes of all children that underwent surgical repair of ventricular septal defects (these included isolated ventricular septal defects, those with multiple ventricular septal defects, as well as those associated with tetralogy of Fallot and double chambered right ventricle) referred to the paediatric cardiothoracic unit at the Charlotte Maxeke Academic Hospital, from the Paediatric Cardiology units at the Charlotte Maxeke Academic Hospital, Chris Hani Baragwanath Academic Hospital and the Rahima Moosa Hospitals between 2001 and 2004, were analysed for the position, number of and size of ventricular septal defects. For this purpose, 11 cadaveric neonatal hearts were dissected while seven post-mortem specimens of the heart, four with isolated ventricular septal defects and three with tetralogy of Fallot were analysed. In addition, 50 cases of isolated ventricular septal defects, 42 cases with tetralogy of Fallot and eight cases with double chambered right ventricle were retrospectively reviewed. The membranous and the muscular septum made up the largest components of the interventricular septum in the normal neonatal hearts. A perimembranous ventricular septal defect was the most common type of defect diagnosed in these patients (the majority of the patients were Black children), 78% of cases with a single isolated ventricular septal defect, 90% in patients with tetralogy of Fallot, and 75% in the group with double chambered right ventricle. The average sizes of all perimembranous defects (from the echocardiogram) were classified as small, moderate or large. An additional interesting finding was prolapse of the right coronary cusp of the aortic valve into the isolated ventricular septal defect and occurred in 22% (11 out of 50) of patients. Aortic regurgitation occurred in association with prolapse of the right coronary cusp in 54.5% (5 out of 11) of cases. This prevalence in black patients is much higher than has been documented in White or Japanese children. Non-compaction of the left ventricle was seen in one post-mortem specimen in association with a perimembranous ventricular septal defect and dilated cardiomyopathy. This recently described abnormality is alluded to in the discussion. Attention is drawn to the abnormality known as double chambered right ventricle, where the size of the ventricular septal defect is variable and where the site of obstruction in the right ventricle is caused by muscle bundles lower than that seen in tetralogy of Fallot. Knowledge of ventricular septal defects found in South African children will help in the assessment and care of these patients with one of the most common congenital cardiac malformations.

No description available.

The formation of the corpus luteum, its maintenance throughout pregnancy and the secretory activity of this transient endocrine gland receive special emphasis because of its role in the secretion of progesterone. An inadequate luteal phase has been associated with an increased incidence of congenital abnormalities. Anything which interferes with the hormonal environment may lead to fetal death or abnormal embryogenesis. Retinoic acid was administered to mice early in pregnancy to induce neural tube defects. Plasma concentrations were determined by high pressure liquid chromatography. Distribution of the retinoic acid was determined by wholebody autoradiography. The hormonal profile during pregnancy was determined in control and retinoic acid treated dams by specific radioimmunoassay for progesterone and 20 alpha dihydroprogesterone. There was no significant effect of retinoic acid on the hormonal profile of treated dams. This suggests that the teratogenic effects of retinoic acid are not due to a change in the hormonal environment. Progesterone and 20 alpha dihydroprogesterone concentrations were significantly increased on days 10 and 10.5 of pregnancy in both treated and control dams. This is the point when pseudopregnancy would end and pregnancy maintenance comes under the control of luteinizing hormone. The increase in 20 alpha dihydroprogesterone concentration at this point in pregnancy was similar to that observed after the administration of prostaglandin F_2alpha (PGF_2alpha). It seems likely that PGF_2alpha and luteinizing hormone act antagonistically during midpregnancy. Concomitant treatment revealed an interaction resulting in an increased progesterone secretion and the conversion of progesterone to 20 alpha dihydroprogesterone. Hence, PGF_2alpha may be released at the point in pregnancy when luteinizing hormone takes over as the major luteotrophin. Luteinizing hormone thus maintains pregnancy in the mouse in the face of an endogenous PGF_2alpha release.