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Biomedical subjects

G Barkai

Publications and source records attributed to G Barkai.

At least 91 records · Page 5Linked to original sources
PubMed1991

Neonatal alloimmune thrombocytopenia in consecutive pregnancies.

Neonatal and antenatal alloimmune thrombocytopenia is caused by the placental passage of maternal antibodies directed against platelet-specific fetal antigens. This disease is analogous to Rhesus hemolytic disease of the newborn and may be complicated by intracranial hemorrhage. Following increased awareness to the disease, it is currently no longer considered to be rare. Recent advances in the utilization of percutaneous umbilical cord blood sampling has led to a dramatic change in both prenatal and intranatal management of affected fetuses. We present a sibship with four infants, three of them found to have alloimmune thrombocytopenia. The neonatal thrombocytopenia in the subsequent births was not shown to be more severe, as could have been expected from the pathophysiologically analogous Rh hemolytic disease of the newborn. The role of prenatal determination of platelet count, intrauterine treatment with immunoglobulins and platelet transfusions, and elective cesarean section, in preventing possible hemorrhagic complications in repeated pregnancies should be reconsidered, taking into account the natural history of this rare disorder.

Blood Platelets↗
PubMed1991

Hypocalciuria of preeclampsia is independent of parathyroid hormone level.

Hypocalciuria is a feature of preeclampsia. The roles of parathyroid hormone (PTH) and vitamin D 1,25(OH)2D3 (calcitriol) in its pathogenesis have not yet been determined. Fourteen preeclamptic women were compared with 12 women with chronic hypertension and 11 normotensives, all in the third trimester. Preeclamptics had the lowest urinary calcium excretion rate (62.1 +/- 32.8 mg/24 hours) compared with chronic hypertensive women (162.6 +/- 97.8 mg/24 hours) and normotensive controls (225.6 = 146.9 mg/24 hours) (P less than .05). Serum PTH was lowest in preeclamptics (9.8 +/- 5.5 pg/mL), in contrast to the chronic hypertensives (18.5 +/- 2.7 pg/mL) and normotensives (16.4 +/- 3.2 pg/mL) (P less than .005). Similarly, urinary cyclic adenosine monophosphate (cAMP) excretion was 2.9 +/- 1.4 mumol/24 hours in the preeclamptics, 5.1 +/- 1.7 mumol/24 hours in the chronic hypertensives, and 4.6 +/- 1.3 mumol/24 hours in the normotensive group (P less than .05). These data suggest that the mechanism of hypocalciuria in preeclampsia is independent of the PTH-calcitriol axis. Therefore, it is suggested that the hypocalciuria of preeclampsia is due to intrinsic renal tubular dysfunction.

Adult↗
PubMed1991

Fetal lateral ventricle choroid plexus cysts: the dilemma of amniocentesis.

Although lateral ventricle choroid plexus cysts in the second-trimester fetus have been considered a benign developmental phenomenon of no clinical significance, an association with trisomy 18 has been suggested. We designed a prospective study to determine whether karyotype analysis is indicated when such cysts are encountered on prenatal sonogram. During a 20-month period, 5400 low-risk pregnant women were examined sonographically in the second trimester to evaluate the prevalence of fetal lateral ventricle choroid plexus cysts and the incidence of ultrasonographic anomalies associated with such cysts in fetuses with trisomy 18 referred from cytogenetic laboratories. Thirty cases of fetal lateral ventricle choroid plexus cysts (0.6%) were detected during the study period; 28 newborns were normal and two had trisomy 18. One of the affected infants had other associated ultrasonographic abnormalities suggesting aneuploidy, whereas no detectable abnormalities could be found in the other. Three other pregnant women were referred to us from the cytogenetics services because fetal karyotype revealed trisomy 18; in all three cases lateral ventricle choroid plexus cysts and other sonographic abnormalities were observed. In total, we scanned five fetuses with trisomy 18, of which all had lateral ventricle choroid plexus cysts and four had associated detectable anomalies. We could not find any association between cyst size, number, or laterality and trisomy 18. In addition to the five cases of trisomy 18 described, we found 33 other fetuses reported with trisomy 18 in the second trimester; of this total, 25 (66%) had lateral ventricle choroid plexus cysts and 30% had no other detectable abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Pregnancy after myocardial infarction: are we playing safe?

The safety of pregnancy after myocardial infarction remains a significant dilemma for both the obstetrician and the cardiologist. Only 20 cases of pregnancy after myocardial infarction have been reported. To clarify this problem, we add our experience of four such cases in which conception occurred 9 months to 9 years after myocardial infarction with no previous consultation. Each woman had an uneventful pregnancy with no cardiac or obstetric complications related to the myocardial infarction. All patients were under the strict supervision of an obstetrician and a cardiologist during pregnancy in our conjoined antepartum-cardiologic clinic. The mode of delivery in all patients was related to the obstetric indications. Our experience and the accumulated experience in the literature demonstrate good prognosis for patients who conceive after myocardial infarction.

Adult↗
PubMed1990

[Cordocentesis for prenatal diagnosis].

Cordocentesis for prenatal diagnosis was being performed in the seventies during the process of fetoscopy. Since then the technique has been used as a diagnostic tool for intrauterine infection, hematological and metabolic disorders and metabolic status of the fetus; and for rapid cytogenic analysis. We report our first 207 cordocenteses performed since December 1985. First puncture was successful in half the cases. The procedure resulted in termination of pregnancy in only 0.96% of cases. Though a new technique, cordocentesis is playing a major role in modern perinatology. The possibility of a direct route to fetal blood vessels early in pregnancy would lead to earlier diagnosis and treatment.

Blood Specimen Collection↗
PubMed1990

Quantification of the fetal electrocardiogram using averaging technique.

A signal analysis procedure is described for obtaining time intervals parameters of the fetal electrocardiogram as recorded from the maternal abdomen. Applying averaging to the fetal electrocardiogram quantification of the PR interval, QRS duration and QT interval were measured. This technique which includes the subtraction of an averaged maternal ECG waveform using cross-correlation function and fast Fourier transform algorithm, enables the detection of all the fetal QRS complexes in spite of their coincidence with the maternal ECGs. Results that were obtained from 21 pregnant women at the gestational age of 32-41 weeks and an example of a recording with fetal premature ventricular contractions are presented. This method shows an important improvement with respect to detection of fetal heart rate and detection of arrhythmia disturbances in the fetal ECG. The averaging procedure can be used to evaluate long-lived alterations in the fetal ECG.

Algorithms↗
PubMed1990

Low-dose aspirin does not influence the clinical course of women with mild pregnancy-induced hypertension.

The effect of low doses of aspirin on women with mild pregnancy-induced hypertension was investigated by means of a prospective, randomized, double-blind trial. Forty-seven women hospitalized at 30-36 weeks' gestation because of mild pregnancy-induced hypertension were treated by a daily dose of either 100 mg aspirin or placebo. The mean blood pressure values, rates of development of severe preeclampsia, gestational ages at delivery, newborn weights, and 5-minute Apgar scores were similar in the aspirin-treated and the placebo-treated groups. We conclude that low-dose aspirin is not curative but is essentially a preventive treatment which, in order to be effective, should be started weeks before clinical signs of preeclampsia are present.

Adult↗
PubMed1990

Maternal serum lipid profile in pregnancies complicated by hypertensive disorders.

Plasma lipoprotein, cholesterol and triglycerides were determined in 34 hypertensive pregnant patients and in 17 healthy full term pregnant women. Pregnancy induced hypertension was diagnosed in 21 patients and chronic hypertension in the remaining 13 women. Serum triglyceride levels were significantly elevated in the hypertensive patients. This elevation was not influenced by either the severity or the etiology of the hypertension. The total cholesterol/HDL and the LDL/HDL ratios were significantly elevated in the severely hypertensive patients, and furthermore the LDL/HDL ratio was elevated in patients receiving anti-hypertensive treatment. The lipid profiles found in hypertensive pregnant patients could be associated with enhancement of pathological lipid deposition in predisposed vessels such as the uterine spiral arteries. Furthermore, the hypertriglyceridemia found in the hypertensive patients may be associated with the hypercoagulability reported in pregnancy induced hypertension.

Cholesterol↗
PubMed1990

High-order multifetal gestation--management and outcome.

During the period 1975-1989, 11 high-order (quadruplet or more) multifetal gestations reaching the second trimester were treated in our department. All pregnancies resulted from ovulation induction therapy. Premature contractions occurred in all cases. Two women delivered stillborn quadruplets vaginally at 25 and 26 weeks' gestation. Nine women had cesarean deliveries at 28-35 weeks; one fetus was stillborn and two of the 39 live-born infants died. Twenty-nine (74%) weighed less than 1500 g and 16 (41%) were below the tenth percentile for gestational age. Thirty infants have been followed for at least 2 years, corrected for gestational age; 21 (70%) are developing normally, two are severely handicapped with both cerebral palsy and mental retardation, four have mild motor delay, and three have mild motor and mental delay.

Adult↗
PubMed1989

The use of aspirin to prevent pregnancy-induced hypertension and lower the ratio of thromboxane A2 to prostacyclin in relatively high risk pregnancies.

We carried out a prospective, randomized, double-blind, placebo-controlled study to investigate the capacity of aspirin to prevent pregnancy-induced hypertension and to alter prostaglandin metabolism. A total of 791 pregnant women with various risk factors for pre-eclamptic toxemia were screened with use of the rollover test (a comparison of blood pressure before and after the woman rolls from her left side to her back) during week 28 or 29 of gestation. Of 69 women with abnormal results (an increase in blood pressure during the rollover test), 65 entered the study and were treated with a daily dose of either aspirin (100 mg; 34 women) or placebo (31 women) during the third trimester of pregnancy. The number of women in whom pregnancy-induced hypertension developed was significantly lower among the aspirin-treated than among the placebo-treated women (4 [11.8 percent] vs. 11 [35.5 percent]; P = 0.024); the same was true for the incidence of preeclamptic toxemia (1 [2.9 percent] vs 7 [22.6 percent]; P = 0.019). The mean ratio of serum levels of thromboxane A2 to serum levels of prostacyclin metabolites after three weeks of treatment decreased by 34.7 percent in the aspirin-treated group but increased by 51.2 percent in the placebo-treated group. No serious maternal or neonatal side effects of treatment occurred in either group. We conclude that low daily doses of aspirin taken during the third trimester of pregnancy significantly reduce the incidence of pregnancy-induced hypertension and pre-eclamptic toxemia in women at high risk for these disorders, possibly through the correction of an imbalance between levels of thromboxane and prostacyclin.

Adult↗
PubMed1989

[Carrier detection and prenatal diagnosis in phenylketonuria, cystic fibrosis and adrenal hyperplasia use of molecular biology techniques].

With the advent of molecular biology techniques the prenatal diagnosis of many inherited diseases is now possible. In our Division of Transplantation Immunology we provide prenatal diagnosis for phenylketonuria (PKU), cystic fibrosis (CF) and congenital adrenal hyperplasia (CAH). In CF and PKU the chromosome carrying the disease gene is identified by the molecular probe, while in CAH it can also be determined by HLA phenotyping. Accurate diagnosis of a disease is dependent on the physical distance on the chromosome between the probe and the disease gene. Chorionic villous sampling allows evaluation of embryos at 9-10 weeks of gestation and also identification of carriers. DNA prepared from white blood cells of members of 4 families with CAH was digested with restriction endonucleases. Southern transfers were hybridized with the probe for 21-hydroxylase, and with 3 HLA probes mapped to both sides of the gene for 21-OH. In 2 families the embryo was found to be normal and in 2 diseased. Using the same techniques, but with probe and endonucleases specific for PKU, prenatal diagnosis was provided for 11 families with that condition. An embryo with PKU was found in each of 2 families, normal ones in 7, and in the remaining 2 families the testing was not informative. As of the present, 6 normal and 2 diseased children have been born, all as predicted. In 8 families with CF, DNA was examined with 5 probes mapped to both sides of the CF gene. Carriers and healthy sibs were identified, and in 1 family prenatal diagnosis was provided.

Adrenal Hyperplasia, Congenital↗
PubMed1989

Prenatal diagnosis of Lesch-Nyhan syndrome: experience with three fetuses at risk.

Our experience with the prenatal detection of the Lesch-Nyhan syndrome (LNS; hypoxanthine-guanine phosphoribosyltransferase (HGPRT) deficiency) in three fetuses at risk is reported. Enzyme activities were measured in cultured amniocytes in two pregnancies, and in tissues and cultures obtained from chorionic villus sampling (CVS) in a third pregnancy. In all tissues the specific activities of HGPRT and adenine phosphoribosyltransferase (APRT) were determined and APRT/HGPRT ratios were calculated. In addition to the enzyme assays, the rate of purine synthesis de novo was assessed in the two amniocyte cultures, and the rate of [14C]hypoxanthine incorporation into nucleotides and sensitivity to azaguanine were measured in one of the amniocyte cultures. We report the diagnosis of normal fetuses by study of amniocytes in two pregnancies and of LNS using CVS in one pregnancy. In all three cases the diagnosis was confirmed.

Adenine Phosphoribosyltransferase↗