Search PubMed⌕ Search

Biomedical subjects

G Barkai

Publications and source records attributed to G Barkai.

At least 37 records · Page 2Linked to original sources
PubMed1999

Perceived personal control (PPC): a new concept in measuring outcome of genetic counseling.

Many researchers have tried to establish criteria for the evaluation of genetic counseling and the assessment of its success. Most studies focused on counseling outcomes mainly educational and reproductive variables. In the present study we introduced the concept of "perceived personal control" (PPC), which captures a wider and more meaningful range of effects of genetic counseling. It was found to be central to coping with health threats and to adapting to a broad spectrum of health problems. This study investigated 154 counseling cases. Counselees were requested to complete pre- and post-counseling questionnaires consisting of a knowledge test, measures of PPC, expectations/evaluations of counseling, and satisfaction with the procedure. Comparisons of mean PPC scores before and after counseling showed significant increases. Higher post-counseling PPC was found among counselees who had been given a definite diagnosis, a specific recurrence risk, and been offered prenatal diagnosis. Post-counseling PPC also correlated with knowledge, satisfaction, counseling evaluations, and expectation fulfillment. The findings suggest that PPC is a valid measure for the evaluation of genetic counseling outcomes. The psychometrically reliable scales developed in this study can become helpful tools for assessing genetic counseling both in research and in clinical practice, helping the counselor evaluate the counseling session and focus on the counselees' needs.

Adult↗
PubMed1999

Detection of numerical chromosome aberrations by comparative genomic hybridization.

At least 50 per cent of all first-trimester spontaneous abortions are cytogenetically abnormal, including trisomy, monosomy X, triploidy, tetraploidy and structural chromosome anomalies. Traditionally, the detection of aneuploidy in fetal tissues is performed by tissue sampling, cell culturing, metaphase spread preparation, and conventional banding analyses. This is a tedious, laborious and time-consuming process, prone to errors due to external contamination, culture failure and selective growth of maternal cells. In the present study, we applied the CGH technique in the detection of numerical chromosome abnormalities in 50 placentae of spontaneously aborted fetuses. CGH detected six different types of trisomy (trisomy 8, 15, 16, 18, 22 and 21), one double trisomy (involving chromosomes 14 and 21), and one monosomy X. Overall, nine samples (18 per cent) harboured numerical chromosome aberrations. Aneuploidy was detected in eight samples by CGH and in six samples by conventional cytogenetic analysis. In only one case, CGH failed to detect a mosaic for trisomy revealed by conventional cytogenetic analysis. The successful application of the CGH technique to the detection of aneuploidy in spontaneous abortions, demonstrates the utility of using this technique to screen prenatally for numerical chromosome abnormalities. Our preliminary data support the application of CGH to the clinical genetics setting, at least as a complementary tool to the traditional cytogenetic techniques.

Abortion, Spontaneous↗
PubMed1999

Long term neurological outcome of herpes encephalitis.

Twenty eight children with herpes simplex encephalitis were followed up for a mean of 5.5 years. Two children died and 26 survived, of whom 16 were left with no neurological sequelae and 10 had persistent neurological sequelae. Mean (SD) Glasgow coma score was significantly lower in the patients with neurological sequelae (7.7 (1.5)) and the patients who died (4.5 (0.7)), compared with the patients without neurological sequelae (11 (1.7)).

Acyclovir↗
PubMed1999

Structural unbalanced chromosome rearrangements resolved by comparative genomic hybridization.

The identification of unbalanced structural chromosome rearrangements using conventional cytogenetic techniques depends on recognition of the unknown material from its banding pattern. Even with optimally banded chromosomes, when large chromosome segments are involved, cytogeneticists may not always be able to determine the origin of extrachromosomal material and supernumerary chromosomes. We report here on the application of comparative genomic hybridization (CGH), a new molecular-cytogenetic assay capable of detecting chromosomal gains and losses, to six clinical samples suspected of harboring unbalanced structural chromosome abnormalities. CGH provided essential information on the nature of the unbalanced aberration investigated in five of the six samples. This approach has proved its ability to resolve complex karyotypes and to provide information when metaphase chromosomes are not available. In cases where metaphase chromosome spreads were available, confirmation of CGH results was easily obtained by fluorescence in situ hybridization (FISH) using specific probes. Thus the combined use of CGH and FISH provided an efficient method for resolving the origin of aberrant chromosomal material unidentified by conventional cytogenetic analysis.

Abortion, Spontaneous↗
PubMed1999

Heat stable and urea resistant alkaline phosphatase in maternal neutrophils from normal and Down syndrome pregnancies.

Activity levels of total and placental alkaline phosphatase (AP) were determined in maternal serum and neutrophils of normal and Down syndrome pregnancies. The placental iso-enzyme (PAP) was identified by its relative stability to urea and heat. Significant increase in the activity of all iso-enzymes across gestational stages was observed in maternal sera of 28 normal pregnancies. However, in the neutrophil extracts of the same blood samples no differences were detected between trimesters. Another set of experiments was aimed at finding diagnostic differences of PAP activity in maternal neutrophils of normal and trisomy 21 affected pregnancies. No differences of heat stable AP activity were found in maternal samples of 19 normal and 19 Down syndrome affected pregnancies. Urea resistant AP proportions were also similar when measured after 40 minutes of exposure (13 samples in each group). However, a marginally significant increase was observed in the mean value of the Down syndrome affected samples, after 60 minutes of urea treatment. In view of the above results we conclude that neutrophil AP activity is not as yet a useful marker for the screening of trisomy 21 fetuses.

Alkaline Phosphatase↗
PubMed1999

Advanced FISH with directly labeled X, Y and 18 DNA probes as a tool for rapid prenatal diagnosis.

OBJECTIVE: To examine a rapid technique for identification and determination of fetal sex chromosomes and one autosome (chromosome 18) in uncultured amniotic fluids using fluorescence in situ hybridization (FISH) with directly labeled DNA probes and ignoring the use of proteinase K and Rnase. STUDY DESIGN: Twenty-five amniotic samples taken from pregnant women who were in their 18th gestational week and had advanced maternal age were studied for analysis of sex chromosomes and chromosome 18 with the FISH technique as well as standard cytogenetic analysis. RESULTS: Four hours after amniocentesis was performed, we identified the sex of the fetuses and disomy of chromosome 18 in a minimal sample of uncultured amniotic fluid by using directly labeled DNA probes for chromosomes X, Y and 18 (VYSIS) and ignoring the use of proteinase K and Rnase. CONCLUSION: The possibility of shortening the time required for identification of aneuploidies in a second-trimester fetus is useful in cases where fetal anomalies are ultrasonically diagnosed at a relatively advanced gestational age.

Adult↗
PubMed1998

Detection of chromosomal aberration in fetuses arising from recurrent spontaneous abortion by comparative genomic hybridization.

Chromosomal abnormalities (mostly aneuploidy) account for approximately 50% of fetal losses in the first 8-15 weeks of gestation. Cytogenetic analysis of aborted fetal material depends on conventional tissue culturing and karyotyping. This technique is laborious and is subject to problems including external contamination, culture failure and selective growth of maternal cells. Comparative genomic hybridization (CGH) was used to determine the chromosomal constitution of 27 fetuses arising from recurrent spontaneous abortion. In 12 samples, the CGH results were compared to the results obtained by conventional cytogenetic techniques. Correlation was found in 75% of samples. Overall, CGH detected chromosomal abnormalities in 48% of the samples, including trisomies, monosomies, and partial chromosome gains and losses. The preliminary data in this study show that CGH can be added, at least as a complementary method, to the traditional cytogenetic techniques used in the investigation of recurrent spontaneous abortions.

Abortion, Habitual↗
PubMed1998

Concurrent use of flow cytometry and fluorescence in-situ hybridization techniques for detecting faulty meiosis in a human sperm sample.

Routine semen analysis in an infertile patient revealed severe teratospermia associated with malformation of head and tail in 100% of the sperm cells. Flow cytometry and fluorescence in-situ hybridization (FISH) were shown to supplement routine semen analysis by providing information on the sperm chromatin. Using flow cytometry, propidium iodide-stained spermatozoa from the same sperm sample were compared with a normal reference pool, and with human lymphocytes. The results point to a population of diploid sperm cells rather than to mature haploid spermatozoa. Numerical chromosomal abnormalities of the spermatozoa were subsequently evaluated using FISH. A total of 1000 sperm cells were scored for X and Y chromosomes, and an additional 1128 sperm cells for chromosome 18. Aneuploidy of chromosomes X and Y was revealed in 96.9% of the cells and of chromosome 18 in 90.3% of the cells. Non-disjunction of chromosome X and Y in meiosis I and II occurred in 54.8 and 2.7% of the sperm cells respectively. Non-disjunction in both meiosis I and II occurred in 39.4% of the sperm cells. A normal haploid pattern for chromosomes X and Y was observed in only 3.1%, and for chromosome 18 in 9.7%, of the cells. Using three colour FISH for the sex chromosomes and for chromosome 18, diploidy was demonstrated in 19.4% of 500 sperm cells and aneuploidy in virtually all sperm cells (99.2%). The use of flow cytometry and FISH in cases where genetic and developmental chromatin abnormalities are suspected is a valuable adjunct to other available techniques, and can guide the clinicians to decide which samples are unsuitable for intracytoplasmic injection.

Adult↗
PubMed1998

Comparative genomic hybridization analysis of nonfunctioning pituitary tumors.

Clinically nonfunctioning pituitary adenomas constitute about one third of pituitary neoplasms and are considered monoclonal tumors. The molecular mechanisms of tumorigenesis in these neoplasms are poorly understood, as evidenced by the paucity of reported somatic genetic alterations. Furthermore, the somatic mutations detected to date were primarily ascribed to candidate genes or chromosomal regions: gsp, ras, p53 mutations, and allelic losses of 11q and 13q. To gain insight into which chromosomal regions bear genes involved in nonfunctioning pituitary tumorigenesis, we examined 23 such tumors by comparative genomic hybridization. Four tumors showed no genetic abnormality, and the rest (17 of 23, 74%) exhibited at least one chromosomal region of abnormality. Gains and losses affected all chromosomes (except for chromosome 14). Notably, 8 of 23 tumors (34.7%) displayed sex chromosome and chromosome 18 aberrations (amplifications or deletions). Nonrandom DNA amplification of sub-chromosomal regions on 4q, 5q (5q13-->5q23), 9p (9p21-->9pter), 13q (13q21-->13q32), and 17q were detected in 10-30% of the tumors. Noteworthy, no tumor displayed deletion of 11q, the MEN1 gene locus. These findings suggest that genes localized to previously undescribed chromosomal regions play a role in the tumorigenesis of nonfunctioning pituitary adenomas.

Adenoma↗
PubMed1997

[Water birth].

Explore the source record for details and available documents.

Bacterial Infections↗
PubMed1997

No founder effect detected in Jewish Ashkenazi patients with fragile-X syndrome.

Several studies on small homogenous populations suggested that fragile-X syndrome originated from a limited number of founder chromosomes. The Israeli Jewish population could serve as an adequate model for tracing a founder effect due to the unique ethnic makeup and traditional lifestyle. Furthermore, a common haplotype for Jewish Tunisian fragile X patients was recently reported. To test for a similar occurrence in the Jewish Ashkenazi population, we performed haplotype analysis of 23 fragile-X patients and 28 normal chromosomes, all Jewish Ashkenazi, using microsatellite markers within and flanking the FMR-1 gene: FRAXAC1, FRAXAC2, and DXS548. The combined triple-marker analysis identified a wide range of diverse haplotypes in patients and controls, with no distinct haplotype prevalent in the patient group. Our data suggest that no common ancestral X chromosome is associated with the fragile-X syndrome in the Israeli Jewish Ashkenazi patient population studied. These findings are in contrast to other reports on founder effect associated with fragile-X syndrome in distinct European as well as Jewish Tunisian populations. On this basis, a more complex mechanism for the development of fragile-X syndrome in the Jewish Ashkenazi population should be considered.

Europe↗
PubMed1997

Induction of labor with use of a Foley catheter and extraamniotic corticosteroids.

OBJECTIVE: Our purpose was to examine the hypothesis that corticosteroids, when administered extraamniotically, can enhance the labor process and reduce the induction-to-delivery interval. STUDY DESIGN: A double-blind, randomized study was conducted on 98 women with a gestational age of 36 to 42 weeks, an unfavorable cervix, and medical indications for delivery, who were assigned to receive either 20 mg of dexamethasone in saline solution (study group, n = 50) or saline solution only (control group, n = 48) administered extraamniotically through an intracervical inflated Foley balloon catheter. The net effect of steroids was assessed with use of multivariant logistic regression analysis. RESULTS: The mean time intervals between induction of labor to the active phase and between induction of labor to delivery were significantly shorter in the study group compared with those of the control group (7.8 +/- 3.1 hours vs 9.9 +/- 3.9 hours, p < 0.03, 11.9 +/- 3.0 hours vs 14.5 +/- 4.8 hours, p < 0.01, respectively). Those not receiving steroids were at a 3.2 higher risk of having a longer time interval of induction to delivery (95% confidence interval 1.1 to 9.5). The general success rate in achieving vaginal delivery was, however, similar between the groups. CONCLUSIONS: Induction of labor with use of an intracervical Foley balloon catheter and extraamniotic corticosteroids reduces the time interval from induction of labor to delivery. This may indicate a possible role for corticosteroids in the parturition process.

Adult↗
PubMed1997

Detection of adeno-associated virus type 2 sequences in the human genital tract.

Adeno-associated virus (AAV) is a defective parvovirus with unknown pathogenicity. It requires helper functions for its normal replication in human tissue and therefore is not readily isolated from clinical specimens. We have used the PCR method to examine the following clinical samples for the presence of AAV sequences: (i) 15 nasopharyngeal aspirates from symptomatic patients, (ii) 7 swab or fluid specimens from vesicles of patients suspected of having varicella-zoster virus infections, (iii) 21 human papilloma virus-positive genital biopsy specimens, (iv) 61 genital swab specimens from women suspected of having herpes simplex virus (HSV) infection examined either directly or following propagation in tissue culture, (v) 62 samples of first-trimester aborted material, including 38 samples from spontaneous abortions and 24 samples from induced abortions, (vi) 11 samples of chorionic villi taken from women undergoing genetic prenatal diagnosis, and (vii) three lots of cultured human embryonic cells. AAV sequences were detected only in samples taken from the genital tracts of women suspected of having HSV infection and not in any of the other types of samples. Samples from 11 patients were positive for AAV: for 4 patients the original swab sample was positive, for 4 patients the cultured swab sample was positive, and for 3 patients both the original swab samples and the cultures were positive. Five of the 11 patients were infected with HSV. Our study demonstrates the presence of AAV in the female genital tract. However, in contrast to a previous report (E. Tobiasch, M. Rabreau, K. Geletneky, S. Larue-Charlus, F. Severin, N. Becker, and J. R. Schlehofer, J. Med. Virol. 44:215-222, 1994), we did not find solid evidence of its replication in maternal or embryonal tissues from the first trimester of pregnancy. The questions of a potential pathogenic etiology of AAV and the interaction with HSV remain open.

DNA, Viral↗
PubMed1996

Prelabour rupture of membranes at term: early induction of labour versus expectant management.

OBJECTIVES: To compare expectant management with early induction of labour in pregnant patients with prelabour rupture of membranes at term and unfavourable cervix. STUDY DESIGN: A prospective, randomised study of 154 women with prelabour rupture of membranes at term of whom 80 had been managed expectantly, and 74 had undergone oxytocin induction at a rate of 2.5 mU/min. Digital examination was not performed before oxytocin infusion, and the first was delayed until 4 h (nulliparae), or 2 h (multiparae) of regular uterine contractions. RESULTS: The mean period from rupture of membranes to delivery was significantly shorter in the induction group. The mean duration of labour was significantly shorter in the expectant group. Operative vaginal deliveries were more common in the induction group, and fetal distress was the most common cause of operative vaginal deliveries. The caesarean rates were low and similar in both groups. Maternal and neonatal infectious morbidity was similar and no difference was found in the length of hospitalisation. CONCLUSIONS: Expectant management in patients with ruptured membranes at term is safe and reduces the frequency of operative vaginal deliveries.

Adult↗
PubMed1996

Pathogenic role of anti-endothelial cell antibodies in vasculitis. An idiotypic experimental model.

Idiotypic manipulation of naive mice has previously been used for induction of systemic autoimmune diseases (e.g., antiphospholipid syndrome, systemic lupus erythematosus, and Wegener's granulomatosis). The aim of this study focused on the utilization of this technique to induce the production of anti-endothelial cells Abs (AECA) and autoimmune vasculitis in a murine model. AECA were derived from a Wegener's granulomatosis patient's plasma. IgG was purified by absorption on a proteinase-3 affinity column resulting in the depletion of anti-neutrophil cytoplasmic Ab activity. The absorbed IgG fraction displayed a high titer of AECA as evidenced by a cyto-ELISA against unfixed human umbilical vein endothelial cells. BALB/c mice were actively immunized with the purified AECA. Three months after a boost injection with the human AECA, mice developed endogenous AECA (AB), but not Abs to proteinase-3, cardiolipin, or DNA. Histologic examination of lungs and kidneys revealed both lymphoid cell infiltration surrounding arterioles and venules; as well as deposition of Igs at the outer part of blood vessel walls. This experimental animal model of vasculitis, a product of our method of idiotypic manipulation, provides the first direct proof for the pathogenicity of AECA.

Animals↗
PubMed1996

Effect of gravidity on maternal serum markers for Down's syndrome.

The effect of gravidity on maternal serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotrophin (hCG) levels was investigated in 27,592 women being screened for Down's syndrome. There was no difference in the median AFP level in primigravid and multigravid women, but the median hCG level in multigravid women was 5.9 per cent lower than in those tested in their first pregnancy (P < 0.0001) and the median uE3 level was 3.9 per cent lower (P < 0.0001). Among multigravid women, there was no material difference in hCG levels according to the number of previous pregnancies or livebirths, whereas uE3 levels declined steadily with increasing numbers. Both markers declined with advancing maternal age: for hCG this was an independent effect, but for uE3 it was due to the correlation between age and gravidity. Allowing for these effects will not greatly alter the Down's syndrome screening detection and false-positive rates.

Adult↗
PubMed1996

Down's syndrome screening marker levels following assisted reproduction.

Maternal serum alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), and unconjugated oestriol (uE3) levels were examined in 1632 women who had ovulation induction and 327 who had in vitro fertilization. There was a highly statistically significant increase in hCG and reduction in uE3 among those with ovulation induction. The median levels were respectively 1.09 and 0.92 multiples of the normal gestation-specific median (MOM) based on a total of 34582 women. Ovulation induction appeared to have no material effect on the median AFP level but this masked a significant increase when treatment was with Clomiphene (1.05 MOM) and a significant decrease when Pergonal was used (0.93 MOM). There was a highly statistically significant reduction in uE3 among women having in vitro fertilization with a median level of 0.92 MOM. Those fertilized with a donor egg (21) had significantly higher AFP and uE3 levels than when their own egg was used. Our results were confounded by differences in gravidity, but formally allowing for this factor did not materially change the findings. None of the observed effects is great enough to warrant routine adjustment of marker levels to allow for them. Moreover, women with positive Down's syndrome screening results can be reassured that this is unlikely to be due to them having had assisted reproduction.

Biomarkers↗