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Biomedical subjects

H Nasrat

Publications and source records attributed to H Nasrat.

10 recordsLinked to original sources
PubMed2005

A prospective, longitudinal study of the renin-angiotensin system, prostacyclin and thromboxane in the first trimester of normal human pregnancy: association with birthweight.

BACKGROUND: Very early human pregnancy is a state of cardiovascular underfilling. The renin-angiotensin system (RAS) is directly concerned with sodium and water homeostasis. Angiotensinogen is known to be the rate-limiting component in the generation of angiotensin I, and hence angiotensin II, in pregnancy. The usual measurement of 'renin activity' does not differentiate between enzyme and substrate. We hypothesized that the RAS is activated from the start of pregnancy; plasma renin concentration (PRC) and angiotensinogen will show differential regulation and might stimulate the rise in prostacyclin. METHODS: A prospective study of 12 nulliparous normal women. PRC and angiotensinogen and excretion of prostacyclin and thromboxane metabolites were measured pre-pregnancy and four to six times after conception to 13 weeks. RESULTS: By 6 weeks gestation, mean PRC was markedly raised and remained stable to 13 weeks. The initial angiotensinogen response varied, but rose consistently after 6-8 weeks. Regression analysis showed angiotensinogen in the first trimester to be strongly associated with corrected birthweight centile (P < 0.001). Excretion of eicosanoid metabolites was very variable, but rose significantly from 6 weeks; the ratio between prostacyclin and thromboxane excretion did not alter over this time. There was no correlation between the various hormones measured. CONCLUSION: Angiotensinogen is known to be rate-limiting in pregnancy. Its association with birthweight may be through effects on early plasma volume expansion and may have implications for intrauterine growth restriction and pre-eclampsia.

6-Ketoprostaglandin F1 alpha↗
PubMed2004

Ultrasound biometry of Arabian fetuses.

OBJECTIVE: To establish fetal ultrasound biometry charts for Arabian fetuses between 14 and 40 weeks of gestation. METHOD: Cross-sectional fetal ultrasound data of normal singleton pregnancies, which had been performed over a period of 7 years, were retrieved. Only pregnant Arab women with certain last menstrual period dates and/or early ultrasound examinations were included. Each fetus contributed to only one set of data. Normal ranges for biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) were established. The mean and 5th and 95th percentiles at 18th, 28th, and 36 weeks of gestation were compared with similar ranges of published data from pregnancies of American and Anglo-Saxon population. RESULTS: Fetal ultrasound biometry has been established for our local population. Comparing our data with Western population emphasizes the presence of significant variation in fetal morphometric measurements, particularly in the later weeks of gestation and at the extremes of the range of fetal size. CONCLUSION: The clinical significance of this variation differs according to the primary objective of ultrasound fetal measurements. For estimation of fetal age, usually by head and femur measurements in early gestation, ethnic variation seems to have limited significance. Whereas for estimation of fetal growth and/or weight in the third trimester, based on abdominal circumference, the use of given points, e.g., 10th or 5th percentile derived from other population charts, has the potential of either over- or underdiagnosis of IUGR fetuses. The adoption of locally developed charts is recommended.

Anthropometry↗
PubMed1996

Determinants of pregnancy outcome in patients with gestational diabetes.

OBJECTIVES: To describe the experience of management of gestational diabetes 'GDM' among a high-risk population and to determine the relative contribution of maternal risk factors and some indices of glucose intolerance on pregnancy outcome. METHODS: A total of 173 antenatal patients with GDM, matched to 337 non-diabetic controls were evaluated. Incidences of fetal macrosomia, large birth weight (> 4000 g), and operative delivery were noted. Patients with GDM were subgrouped into group I and II, according to the fasting blood glucose (FBG) level on the glucose tolerance test 'GTT', whether > or = or < 5.8 mmol/l, respectively. A logistic regression model was then developed with predictive variables, i.e. maternal weight, height, parity, gestational week at diagnosis of GDM, degree of glucose tolerance, treatment and means of fasting and post-prandial blood glucose measurements as independent variables against each of the outcome measures as dependent variables. RESULTS: Compared with non-diabetics, patients with GDM were older in age, weight and parity. The mean fetal birth weight, incidences of macrosomia and babies > 4 kg were significantly higher among GDM patients. In patients with GDM the degree of glucose intolerance (determined by FBG on the GTT) and maternal weight were the only variables that significantly increased the risk of macrosomia and operative delivery. Within group I patients (FBG > or = 5.8 mg/dl) only 'maternal weight' significantly increased the risk of both having a baby > 4 kg, and operative delivery. CONCLUSION: Among patients with gestational diabetes, a GTT with a FBG level > or = 5.8 mmol/l is a strong predictor for perinatal outcome. Maternal weight is an independent risk factor that increases the risk of both macrosomia and operative delivery.

Adult↗
PubMed1992

Midpregnancy plasma zinc in normal and growth retarded fetuses--a preliminary study.

OBJECTIVE: To determine plasma zinc concentrations in normally and abnormally growing fetuses. DESIGN: Prospective observational study. SETTING: Fetal Medicine Unit, Queen Charlotte's Maternity Hospital. SUBJECTS: 53 pregnant women attending for fetal blood sampling at between 18 and 40 weeks gestation. 27 fetuses were normal (central group), 11 fetuses were growth retarded and 15 were malformed. MAIN OUTCOME MEASURES: Plasma zinc concentrations in maternal and fetal blood at time of fetal blood sampling. RESULTS: In normally growing fetuses, between 18 and 40 weeks gestation, there was no fall in maternal plasma zinc concentration; the fetal level fell by 36%. In 10 fetuses with symmetrical growth retardation, plasma zinc concentration tended to be low, but was not significantly different from that in the normal control fetuses. CONCLUSION: The results suggest that (i) placental transfer of zinc is an uphill secretory process and that it is a rate-limiting step in the accumulation of zinc by the fetus and (ii) in fetuses with symmetrical intrauterine growth retardation, a low plasma zinc is probably a parallel phenomenon and not necessarily an aetiological factor.

Female↗
PubMed1991

Fetal liver dysfunction in Rh alloimmunization.

The liver enzymes, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP), were measured in the blood of 25 fetuses with severe Rh alloimmunization at the time of their first, second and third intravascular transfusions and in 17 comparison fetuses. In the comparison group, GGT increased with advancing gestation (r = 0.7; P = 0.002), whereas ALP, AST and ALT did not correlate with gestational age. Rh hydropic fetuses (n = 8) had higher blood ALT levels than the comparison fetuses (P = 0.008) had significantly increased transaminases when compared with non hydropic fetuses (n = 17). In hydropic fetuses, AST correlated with the nucleated red cell count before transfusion (r = 0.94; P = less than 0.0001). Fetal transaminases were no longer increased in hydropic fetuses by the second (AST) or third (ALT) transfusion. In both hydropic and non hydropic fetuses, GGT increased by the second transfusion (median percentage change +85%, range -83% to +596%; P = 0.003). The rise in fetal GGT was transitory and correlated with the increase in fetal haematocrit at the first transfusion (r = 0.58; P = 0.006). This study reports liver dysfunction secondary to extramedullary erythropoiesis in Rh alloimmunization and implicates portal hypertension for the rise in fetal GGT with transfusion.

Alanine Transaminase↗
PubMed1991

Fetal blood sampling from the intrahepatic vein for rapid karyotyping in the second and third trimesters.

One hundred and twelve fetuses with structural anomalies (n = 84), intrauterine growth retardation (n = 21) or amniotic fluid volume disorders (n = 7) detected by ultrasound underwent blood sampling from the intrahepatic vein for rapid karyotyping. The procedure was successful in 95.5%. 12.5% of the fetuses had an abnormal karyotype. Fetal bradycardia was observed in two fetuses (1.8%) and intraperitoneal bleeding in three (2.7%). There were three procedure-related losses but these were not due to the intrahepatic vein sampling itself. Fetal blood sampling is the method of choice for rapid karyotyping in the second and third trimesters, and the intrahepatic vein is an alternate site when access is difficult or failure to sample occurs at the placental cord insertion. Additional advantages of fetal blood sampling at the intrahepatic vein include absence of cord complications, reduced risk of fetal blood loss and fetomaternal haemorrhage, and the lack of need to confirm the fetal origin of the sample.

Blood Specimen Collection↗
PubMed1991

X-ray pelvimetry-reappraisal.

Antenatal erect lateral X-ray pelvimetry was performed for 116 primigravidas and 53 multigravidas because of suspected cephalopelvic disproportion (CPD). Multigravidas were further subgrouped into 4 gravidas and greater than 4 gravidas. In the primigravidas, there was no statistical difference in the mean value of the anteroposterior diameter of the pelvic inlet (APD) of the elective (10.4 cm, +/- 0.6 SD) and the emergency (10.5 cm, +/- 0.9 SD) caesarean section group. In the multigravidas, the mean value of the APD showed a statistically significant decrease with increased parity. In this group, the chances of delivery by caesarean section were 74%, when the APD was less than 10.5 cm, and 12% if the APD was greater than 11.5 cm. It is concluded that cephalopelvic disproportion in primigravidas should only be diagnosed after adequate trial of labour with adequate uterine contractions. In multiparous patients, especially grand multiparas, X-ray pelvimetry is recommended in cases of suspected CPD before a trial of vaginal delivery is conducted, since the mode of delivery seems to depend primarily on the pelvic capacity.

Birth Weight↗
PubMedDate not supplied

Anthropometric measurement of newborns of gestational diabetic mothers: does it indicate disproportionate fetal growth?

Anthropometric and skinfold measurements in 51 newborns of mothers with gestational diabetes were compared to reference ranges obtained from measurements of 501 newborns of nondiabetic mothers. In newborns of diabetic mothers, the means of fetal birth weight, biceps, subscapular, suprailiac skinfolds, and total fat index measurements (the sum of all measurements) were significantly greater than those of the nondiabetic group. While the means of fetal crown-heel length and head circumference did not significantly differ between the two groups, these findings suggest a disproportionate pattern of growth in fetuses of diabetic mothers, with increased tendency for deposition of subcutaneous fat. The studied population were then stratified into six categories according to birth weight percentiles. Within each category, the skinfold measurements in newborns of diabetic mothers were greater--though the difference was not statistically significant than that of nondiabetic mothers. It is possible, however, that in severe cases of maternal diabetes, the risks of complications, such as shoulder dystocia, increase with disproportionate deposition of subcutaneous fat. These risks appear greater than in fetuses of nondiabetic mothers at a comparable birthweight.

Adipose Tissue↗