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H Zakut

Publications and source records attributed to H Zakut.

At least 73 records · Page 4Linked to original sources
PubMed1990

Acetylcholinesterase and butyrylcholinesterase genes coamplify in primary ovarian carcinomas.

The genes for acetylcholinesterase (ACHE) and butyrylcholinesterase (CHE) are expressed in multiple tumor tissues, including ovarian carcinomas. Both CHE and ACHE genes coamplify in leukemias. To examine the relationship of gene amplification to the expression of these genes in tumors, ACHE and CHE genes and their expression were studied in primary ovarian carcinomas. DNA blot hybridization demonstrated a significant amplification and mutagenesis of both genes in 6 of 11 malignant tumors studied. This was greater or of the same order of magnitude as the amplification of the oncogenes c-rafi, v-sis, and c-fes in these tumors. No amplification was found in normal ovarian tissues or benign ovarian cysts. Xenopus oocyte microinjections, blot and in situ hybridizations, and immuno- and cytochemical staining revealed translatable CHEmRNA and its active protein product in discrete tumor foci. The frequent coamplification in ovarian carcinomas of ACHE and CHE genes implicates cholinesterases in neoplastic growth and/or proliferation.

Acetylcholinesterase↗
PubMed1990

Endocrine profile associated with estrogen and progesterone receptors in leiomyoma and normal myometrium.

In leiomyoma and normal myometrium estrogen receptors act independently at low or high levels of the normal serum steroid range in the menstrual cycle. It might be an inherent characteristic of leiomyomas, which results in their progressive growth in the absence of any abnormal stimulation. In the secretory phase of the menstrual cycle, serum progesterone suppresses estrogen receptor concentrations in leiomyoma. In the present study serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) showed direct as well as inverse correlations with estrogen and progesterone receptors in different phases of the menstrual cycle.

Estradiol↗
PubMed1989

Expression and tissue-specific assembly of human butyrylcholine esterase in microinjected Xenopus laevis oocytes.

Cholinesterases represent a ubiquitous, polymorphic family of acetylcholine hydrolyzing enzymes. The multileveled tissue-specific heterogeneity which characterizes these enzymes makes the cholinesterases an appropriate model for studying the mechanisms involved in regulating divergent pathways in protein biogenesis. For this purpose, a cDNA coding for human butyrylcholine esterase (BuChE) was subcloned into the SP 6 transcription vector. Synthetic mRNA transcribed from this construct was microninjected into Xenopus laevis oocytes alone, and in conjunction with poly(A)+ RNAs extracted from human brain or muscle. Injected BuChE-mRNA induced the biosynthesis of a protein exhibiting the catalytic activity, substrate specificity, and sensitivity to selective inhibitors characteristic of native human serum BuChE, and clearly distinct from the related enzyme acetylcholinesterase (AChE). The nascent BuChE was reproducibly distributed into low salt-soluble and detergent-extractable pools. Sucrose gradient analysis demonstrated that the nascent human enzyme was capable of limited subunit assembly, appearing as functional dimeric molecules in both of these fractions. Co-injection with brain or muscle-derived mRNAs facilitated higher order oligomeric assembly. Co-injected brain mRNA induced the appearance of tetramers while co-injected muscle mRNA induced the appearance of an array of heavy molecular forms, including a heavy 16 S form. These results indicate that the molecular determinants which distinguish BuChE from AChE are inherent to its primary amino acid sequence and that additional, tissue-specific protein(s) are involved in the modulation of subunit assembly within particular biological milieues.

Animals↗
PubMed1989

[Standard meal substitute for oral glucose tolerance test in pregnancy].

The oral glucose tolerance test (OGTT) has been the recommended method of screening for the diagnosis of gestational diabetes. Based on the glycemic index of common foods, a standard meal was designed as a substitute meal test (SMT). It consisted of 3 slices of toast (75 g) with 60 g of jam, 11 g of sugar in a cup of tea, and 150 g of canned puree sweetened with sugar (8%), for a total of 118 g of available carbohydrate and a total of 518 cal. Plasma glucose concentrations of 46 pregnant women in the 2nd and 3rd trimesters were determined at 20 minute intervals for 3 hours after ingestion of this SMT, and were compared with those after a 100 g OGTT meal. There was a high correlation (r = 0.96, p less than 0.001) between comparable glucose concentrations after the 2 tests. With the SMT there were significantly fewer side-effects (nausea and vomiting), a higher level on preference scoring and reduced interassay variability of glucose levels after 2 hours. 6 gestational diabetics were diagnosed by the OGTT. In these patients glucose concentrations were higher than 3 standard deviations above the mean 2 hours after ingestion of the SMT. We propose the SMT as a side-effect-free, reliable and convenient alternative to the OGTT in pregnancy.

Blood Glucose↗
PubMed1989

[In-situ hybridization on chorionic villi chromosomes].

Novel techniques for the prenatal diagnosis of inherited defects are currently being developed. The long-range aim is to be able to predict precisely, at an early stage of fetal development, the tendency of the fetus to develop multiple genetic, congenital or acquired diseases. We adapted the technique of gene mapping by in-situ hybridization for use with chromosomes from fetal chorionic villi sampling (CVS). Refined mapping of the genes coding for cholinesterase (CHE) in comparison with the haptoglobin and the transferrin receptor genes on CVS chromosomes Nos. 3 and 16 revealed 3 CHE genes in positions 3q21, 3q26, and 16q12. In view of genetic linkage data, at least 2 of these appear to be potentially active. These findings demonstrate that genes, for which molecularly cloned DNA probes are available, may be localized on CVS chromosomes by comparing their localization with that of known genes after in-situ hybridization. The implications for prenatal diagnosis are promising.

Cholinesterases↗
PubMed1989

Tissue-specific processing and polarized compartmentalization of clone-produced cholinesterase in microinjected Xenopus oocytes.

1. To approach the involvement of tissue-specific elements in the compartmentalization of ubiquitous polymorphic proteins, immunohistochemical methods were used to analyze the localization of butyrylcholinesterase (BuChE) in Xenopus oocytes microinjected with synthetic BuChEmRNA alone and in combination with tissue-extracted mRNAs. 2. When injected alone BuChEmRNA efficiently directed the synthesis of small membrane-associated accumulations localized principally on the external surface of the oocyte's animal pole. Tunicamycin blocked the appearance of such accumulations, suggesting that glycosylation is involved in the transport of nascent BuChE molecules to the oocyte's surface. Coinjection with brain or muscle mRNA, but not liver mRNA, facilitated the formation of pronounced, tissue-characteristic BuChE aggregates. 3. These findings implicate tissue-specific mRNAs in the assembly of the clone-produced protein and in its nonuniform distribution in the oocyte membrane or extracellular material.

Animals↗
PubMed1989

Cholinoceptive properties of human primordial, preantral, and antral oocytes: in situ hybridization and biochemical evidence for expression of cholinesterase genes.

In addition to their well-known involvement in neuromuscular junctions and in brain cholinergic synapses, cholinergic mechanisms have been implicated in the growth and maturation of oocytes in various species. Functional acetylcholine receptors were electrophysiologically demonstrated in amphibian and mammalian oocyte membranes, and activity of the acetylcholine-hydrolyzing enzyme, acetylcholinesterase (AChE), was biochemically measured in the exceptionally big oocytes of the frog Xenopus laevis. However, biochemical methods could not reveal whether AChE was produced within the oocytes themselves or in the surrounding follicle cells. Furthermore, this issue is particularly important for understanding growth and fertilization processes in the much smaller human oocytes, in which the sensitivity of AChE biochemical measurements is far too low to be employed. To resolve this question, a molecular biology approach was combined with biochemical measurements on ovarian extracts and sections. To directly determine whether the human cholinesterase (ChE) genes are transcriptionally active in oocytes, and, if so, at what stages in their development, the presence of ChE mRNA was pursued. For this purpose frozen ovarian sections were subjected to in situ hybridization using 35S-labeled human ChE cDNA. Highly pronounced hybridization signals were localized within oocytes in primordial, preantral, and antral follicles, but not in other ovarian cell types, demonstrating that within the human ovary ChE mRNA is selectively synthesized in viable oocytes at different developmental stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Is it safe to prescribe hormonal contraception and replacement therapy to patients with premalignant and malignant uterine cervices?

The levels of estrogen and progesterone receptors in normal and abnormal uterine cervices were determined. The study group consisted of 14 patients with cervical intraepithelial neoplasia (CIN III) and 7 patients with invasive carcinoma of the cervix (stage IB-IIA). The control group included 23 patients who underwent total abdominal hysterectomy for menorrhagia, leiomyoma, etc. The concentration of total estrogen receptors in premalignant and malignant cervices did not differ from the patients with benign conditions of the cervix. The concentration of progesterone receptors was significantly higher in the nonaffected cervices than in the patients with preinvasive and invasive carcinoma of the cervix (P less than 0.05). We have shown that estrogen receptor concentrations do not differ between women with normal and abnormal uterine cervices. Therefore, we feel that the contraceptive pill is not contraindicated in women who have been treated for CIN III. We also maintain that hormone replacement therapy should be given, when indicated, to women who have been castrated following surgery and/or radiotherapy for invasive carcinoma of the cervix.

Adolescent↗
PubMed1989

Coamplification of human acetylcholinesterase and butyrylcholinesterase genes in blood cells: correlation with various leukemias and abnormal megakaryocytopoiesis.

To study the yet unknown role of the ubiquitous family of cholinesterases (ChoEases) in developing blood cells, the recently isolated cDNAs encoding human acetylcholinesterase (AcChoEase; acetylcholine acetylhydrolase, EC 3.1.1.7) and butyrylcholinesterase (BtChoEase; cholinesterase; acylcholine acylhydrolase, EC 3.1.1.8) were used in blot hybridization with peripheral blood DNA from various leukemic patients. Hybridization signals (10- to 200-fold intensified) and modified restriction patterns were observed with both cDNA probes in 4 of the 16 leukemia DNA preparations examined. These reflected the amplification of the corresponding AcChoEase and BtChoEase genes (ACHE and CHE) and alteration in their structure. Parallel analysis of 30 control samples revealed nonpolymorphic, much weaker hybridization signals for each of the probes. In view of previous reports on the effect of acetylcholine analogs and ChoEase inhibitors in the induction of megakaryocytopoiesis and production of platelets in the mouse, we further searched for such phenomena in nonleukemic patients with platelet production disorders. Amplifications of both ACHE and CHE genes were found in 2 of the 4 patients so far examined. Pronounced coamplification of these two related but distinct genes in correlation with pathological production of blood cells suggests a functional role for members of the ChoEase family in megakaryocytopoiesis and raises the question whether the coamplification of these genes could be causally involved in the etiology of hemocytopoietic disorders.

Acetylcholinesterase↗
PubMed1989

De novo amplification within a "silent" human cholinesterase gene in a family subjected to prolonged exposure to organophosphorous insecticides.

A 100-fold DNA amplification in the CHE gene, coding for serum butyrylcholinesterase (BtChoEase), was found in a farmer expressing the "silent" CHE phenotype. Individuals homozygous for this gene display a defective serum BtChoEase and are particularly vulnerable to poisoning by agricultural organophosphorous insecticides, to which all members of this family had long been exposed. DNA blot hybridization with regional BtChoEase cDNA probes suggested that the amplification was most intense in regions encoding central sequences within BtChoEase cDNA, whereas distal sequences were amplified to a much lower extent. This is in agreement with the "onion skin" model, based on amplification of genes in cultured cells and primary tumors. The amplification was absent in the grandparents but present at the same extent in one of their sons and in a grandson, with similar DNA blot hybridization patterns. In situ hybridization experiments localized the amplified sequences to the long arm of chromosome 3, close to the site where we previously mapped the CHE gene. Altogether, these observations suggest that the initial amplification event occurred early in embryogenesis, spermatogenesis, or oogenesis, where the CHE gene is intensely active and where cholinergic functioning was indicated to be physiologically necessary. Our findings demonstrate a de novo amplification in apparently healthy individuals within an autosomal gene producing a target protein to an inhibitor. Its occurrence in two generations from a family under prolonged exposure to parathion indicates that organophosphorous poisons may be implicated in previously unforeseen long-term ecological effects.

Butyrylcholinesterase↗
PubMed1989

Gene mapping on chorionic villi chromosomes by hybridization in situ: localization of cholinesterase cDNA binding sites to chromosomes 3q21, 3q26-ter and 16q21.

To adapt the in-situ hybridization approach for use in very early fetal development, comparative in-situ hybridization was initiated on chromosomes from chorionic villus sampling (CVS). An additional aim was to refine the localization of the chromosomal sites binding butyrylcholinesterase (BuChE) cDNA by mapping them in parallel to previously mapped genes of close locations. BuChEcDNA was previously found to bind to the long arms of lymphocyte chromosomes 3 and 16, with a wide distribution of grains suggesting two separate sites on chromosome 3. When labelled with 35S and hybridized with CVS chromosomes, BuChEcDNA was bound to three distinct sites, designated CHEL1, CHEL2 and CHEL3. These peaked at 3q21, 3q26-ter and 16q21 respectively. Parallel hybridization with the cDNA encoding transferrin receptor (TFRC) refined its localization to 3q29, in agreement with previously published results and in a distal position to CHEL2, whereas haptoglobin cDNA (HPcDNA) was correctly mapped at 16q24, distal to CHEL3. In view of the published genetic linkage between the CHEL1 locus and the transferrin TF gene on 3q25, this study suggests that one of the three sites carrying BuChE-coding sequences, namely CHEL2, harbours the functional CHEL1 gene. Thus, in-situ hybridization provides a rapid and precise method for the localization of genes on CVS chromosomes, in comparison with known DNA markers.

Binding Sites↗
PubMed1989

Chorionic villi sampling for early prenatal diagnosis: an option for the Jewish orthodox community.

The Jewish religion permits abortion up to 40 days after conception. To accommodate the Jewish orthodox community, prenatal diagnosis in the eighth gestational week may be a feasible goal with clear benefits. We present our experience with chorionic villus sampling (CVS), wherein out of 144 patients requesting CVS, 125 were found to be suitable for the procedure. Excluding patients with fundal placenta and cervical or uterine myoma, chorionic sampling was successfully performed on 102 out of 106 patients (96.2%) and a chromosome result was available for 98 of those patients (96%). Fetal losses, within 14 days following procedure, were 2 out of 125 (1.6%). No complications were encountered following the procedure. The cytogenetic analysis was improved by culturing CVS fragments for 48 h, after which clearer banding patterns could be observed. One of the CVS preparations, from a 7.2/7-week-old embryo was successfully examined. Short-term (6 days) cultures were used as an additional method for chromosome analysis, to extend and confirm results obtained by the direct method.

Abortion, Spontaneous↗
PubMed1989

Management of tubal pregnancy with methotrexate.

Ten women with tubal ectopic pregnancy were treated by the injection of methotrexate into the gestational sac under direct laparoscopic vision followed by a course of intramuscular therapy including folinic acid rescue. One course of treatment induced resolution of the extrauterine pregnancy in eight women. Complete resolution (beta-hCG less than 10 miu/ml) was achieved within 6-47 days (mean 14.5 days). Serum beta-hCG levels started to decline 3.4 days from the beginning of therapy. Length of hospital stay was 5-11 days (mean 6.4 days). Treatment failed in two patients. One woman had a laparoscopic tubal clip sterilization concomitantly with methotrexate treatment. Tubal patency was demonstrated in all the other seven women (100%) tested subsequently. There is a need to establish criteria for patient selection before methotrexate becomes a routine treatment for tubal pregnancy.

Adult↗
PubMed1989

Definition, at the molecular level, of a thyroglobulin-acetylcholinesterase shared epitope: study of its pathophysiological significance in patients with Graves' ophthalmopathy.

The nature of the putative autoantigen in Graves' ophthalmopathy (Go) remains an enigma but the sequence similarity between thyroglobulin (Tg) and acetylcholinesterase (ACHE) provides a rationale for epitopes which are common to the thyroid gland and the eye orbit. In an attempt to define the shared epitope, we have screened a lambda gt 11 human thyroid cDNA library using a polyclonal antibody to Torpedo ACHE and isolated two clones, which upon sequencing, were shown to contain Tg segments, corresponding to portions of the C terminal part of the molecule which has a high similarity with ACHE. Having demonstrated the existence of an epitope common to Tg and ACHE, the clones have been further tested and found to be positive in lysis plaque assays with 1/10 sera from patients with Hashimoto's thyroiditis (HT), 8/8 from patients with Graves' ophthalmopathy and 0/8 normal sera. We have investigated the physiological significance of this common epitope by in situ immunolocalization studies in which the polyclonal antibody to Torpedo ACHE (which was used for screening the library) and immunoglobulins (Igs) from 6 Go patients tested were shown to bind to end plate regions of human foetal muscle fibres which were concurrently shown to be rich in cholinesterase activity: Igs from 3 normal individuals and 2 patients with Hashimoto's thyroiditis did not bind. The results demonstrate and characterize an epitope which is common to Tg and ACHE and show that Go patients Igs contain antibodies which bind to muscle end plates rich in cholinesterase. The significance of these findings to the pathogenesis of Go is discussed.

Acetylcholinesterase↗
PubMed1989

Diurnal variations in unconjugated plasma and total urinary estriol levels in late normal pregnancy.

Diurnal variations in plasma unconjugated estriol and urinary estriol were assessed in 12 pregnant women during the 3rd trimester of uncomplicated pregnancies. Commercially available 125I-labelled radioimmunoassay kits were used. The preliminary data presented here support the hypothesis that there is no circadian rhythm of unconjugated plasma estriol in normal late pregnancy. Total urinary estriol reaches a nadir during the sleep hours (24.00-6.00). A biological carrier 'stick' for estriol measurements might serve as test of choice in the monitoring of high-risk pregnancy as well as for identifying pregnancies complicated by chromosomal abnormalities (e.g., Down's syndrome).

Adult↗
PubMed1989

The incidence and significance of serum hCG and CEA in patients with gastrointestinal malignant tumors.

Beta-human chorionic gonadotropin (hCG) is normally produced and secreted by trophoblastic cells in pregnancy, by tumors arising from those cells and by a wide variety of tumors of nonendocrine origin. Gonadotropin is produced and secreted by various tissues (stomach, pancreas, ovary, etc.) and the incidence of ectopic secretion varies between 0 and 43%. Our report is an attempt to evaluate the incidence of high plasma beta hCG levels in 101 patients with gastrointestinal malignant tumors. The results revealed negative beta hCG in the control samples, while in the studied patients 41 were positive for beta hCG (44.4%). Three samples from oesophagus squamous cell carcinoma were positive. Twenty-five out of 69 with colorectal carcinoma had raised serum beta hCG (36.8%). Gastric carcinoma showed positive beta hCG in 52% of the patients. Among all the patients high beta hCG levels were far more common in those with positive lymphnodes (P less than 0.05). The beta hCG levels decreased with colorectal carcinoma tumor size and with smaller tumors there was the probability of increasing positive serum measurements (P less than 0.05). The patients with adenocarcinoma of the stomach showed good statistical correlation between stages of the disease at the operation time to beta hCG levels. In our opinion this serological assay will become one of the markers to be added to our armamentarium in the evaluation of patients with gastrointestinal malignant tumors.

Adenocarcinoma↗
PubMed1988

Modified properties of serum cholinesterases in primary carcinomas.

Cholinesterases were characterized in the serum of 77 treated and 11 untreated patients having primary carcinomas of various tissue origins and 21 healthy volunteers which served as controls. In most of the samples, pseudocholinesterase (BuChE) accounted for almost all cholinesterase (ChE) activity and was inhibited by the organophosphorous poison tetraisopropyl pyrophosphoramide (iso-OMPA). In samples from the tumor-bearing patients, ChE degraded 733 +/- 59 nmole acetylcholine/h/mg protein, lower than the 960 +/- 175 nmole/hour/mg levels measured in controls. Tumor serum ChE exhibited elevated sensitivity to 1,5-bis-(4-allyldimethyl ammonium phenyl)-pentan-3-one dibromide (BW), the selective bisquaternary inhibitor of "true" acetylcholinesterase (AChE), with no correlation to age, sex, staging of tumor, presence of metastases or the specific treatment protocol, and with a different distribution pattern from the decrease in ChE specific activity or the sensitivity to iso-OMPA. In sucrose gradients, ChE sedimented as 12S in controls whereas in tumor serum samples from treated patients an additional component of 6 to 7 S, inhibited by both iso-OMPA and BW, also was detected. However, the ChE activity in serum of patients with diagnosed carcinomas before surgery and medical treatment appeared to be nondistinguishable from controls. These findings suggest that the modified properties of serum cholinesterases in carcinoma patients are not the result of the tumor itself, but that the common therapy protocols used in the treatment of primary carcinomas may cause the appearance of soluble ChE activity with properties of both AChE and BuChE, which accumulates in the serum.

Adult↗