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Biomedical subjects

H Zakut

Publications and source records attributed to H Zakut.

At least 91 records · Page 5Linked to original sources
PubMed1988

Prenatal sonographic diagnosis of endocardial fibroelastosis secondary to aortic stenosis.

Endocardial fibroelastosis is characterized by a diffuse thickening of the left ventricular endocardium with or without other cardiac anomalies. This entity had been diagnosed prenatally previously (Bovicelli et al., 1984) at a gestational age of 36 weeks. A case of endocardial fibroelastosis due to aortic stenosis accompanied by pericardial effusion, ascites, and hydramnion, diagnosed ultrasonographically and confirmed pathologically at 21 weeks of gestation, is presented.

Adult↗
PubMed1988

Synthesis and localization of plasma proteins in the developing human brain. Integrity of the fetal blood-brain barrier to endogenous proteins of hepatic origin.

The distribution and possible origins of plasma proteins in the human embryonic and fetal brain at different stages of development have been investigated by a combination of isolation and translation of mRNAs and immunocytochemistry using specific antisera. As many as 23 plasma-like proteins have been identified using immunocytochemical methods at the light microscopical level. The presence of mRNAs for 13 of the immunocytochemically positive plasma proteins was demonstrated by in vitro and in ovo translation followed by crossed immunoelectrophoresis and autoradiography; this indicates in situ synthesis of these proteins (e.g., alpha-fetoprotein, alpha 1-antitrypsin, GC-globulin, alpha 2-macroglobulin, pseudocholinesterase, and transferrin) in some brain regions. The regional distribution of some proteins and the absence of some mRNAs suggest that the presence of certain plasma proteins in developing brain may be accounted for by uptake from csf or via nerve processes extending beyond the blood-brain barrier. In several cases, specific proteins appear to be associated with defined cell types, e.g., alpha-fetoprotein, GC-globulin, and ceruloplasmin with neurons, alpha 2-macroglobulin with endothelial cells, and ferritin with glial cells. Some proteins were associated with two or three cell types, e.g., alpha 1-antitrypsin with neurons and glia, and transferrin and alpha 2HS-glycoprotein with neurons, glia, and endothelial cells. Comparison of the expression of mRNAs from fetal brain and liver injected into Xenopus oocytes showed that a few proteins (transferrin and ceruloplasmin) were secreted when liver mRNA was injected, but not when brain mRNA was injected. This suggests that there may be an important difference in the structure and/or processing of these proteins in the brain which may reflect a function different from that associated with them when they originate from the liver. Staining was generally intracellular rather than extracellular; plasma proteins were not associated with the areas immediately around blood vessels although there was a strong immunoprecipitation for each protein within the lumen of cerebral blood vessels. These immunocytochemical findings together with the identification of mRNAs for a large number of plasma proteins in immature brain are discussed in relation to animal experimental work which suggests that the blood-brain barrier to protein is present even at very early stages of brain development.

Blood Proteins↗
PubMed1988

Antibodies against acetylcholinesterase and low levels of cholinesterases in a patient with an atypical neuromuscular disorder.

Antibodies against acetylcholinesterase were found in the serum of a patient presenting dyspnea, generalized muscle paresis, diminished tendon reflexes, and fasciculations. Electrodiagnostic studies showed a decremental response, an incomplete interference pattern, and reduced motor nerve conduction velocity. Edrophonium administration resulted in extreme cholinergic crisis. Biopsies displayed muscle atrophy and nervous tissue degeneration. Recurrent acute respiratory failure ended in death. The patient's serum pseudocholinesterase and red blood cells acetylcholinesterase levels were generally very low, with periodical fluctuations. Minute quantities of the patient's serum inhibited the activity of cholinesterases from normal human serum and from various fetal tissues. Enzyme inhibition was abolished following preadsorption of the serum immunoglobulins with goat antihuman Fab, and radioiodinated acetylcholinesterase from human erythrocytes was precipitated by the patient's serum, confirming that anticholinesterase antibodies were present. Acetylcholinesterase extracted from fetal striated muscle with detergent and salt was inhibited to a larger extent than the enzymes similarly prepared from other fetal tissues and more efficiently than buffer-soluble muscle enzyme. These findings suggest that the patient's serum contained antibodies which interacted preferentially with the membrane-associated forms of muscle acetylcholinesterase and indicate that autoantibodies against acetylcholinesterase could play a role in the pathogenesis of the disease.

Acetylcholinesterase↗
PubMed1988

Cross-homologies and structural differences between human cholinesterases revealed by antibodies against cDNA-produced human butyrylcholinesterase peptides.

To study the polymorphism of human cholinesterases (ChEs) at the levels of primary sequence and three-dimensional structure, a fragment of human butyrylcholinesterase (BuChE) cDNA was subcloned into the pEX bacterial expression vector and its polypeptide product analyzed. Immunoblot analysis revealed that the clone-produced BuChE peptides interact specifically with antibodies against human and Torpedo acetylcholinesterase (AChE). Rabbit polyclonal antibodies prepared against the purified clone-produced BuChE polypeptides interacted in immunoblots with denatured serum BuChE as well as with purified and denatured erythrocyte AChE. In contrast, native BuChE tetramers from human serum, but not AChE dimers from erythrocytes, interacted with these antibodies in solution to produce antibody-enzyme complexes that could be precipitated by second antibodies and that sedimented faster than the native enzyme in sucrose gradient centrifugation. Furthermore, both AChE and BuChE dimers from muscle extracts, but not BuChE tetramers from muscle, interacted with these antibodies. To reveal further whether the anti-cloned BuChE antibodies would interact in situ with ChEs in the neuromuscular junction, bundles of muscle fibers were microscopically dissected from the region in fetal human diaphragm that is innervated by the phrenic nerve. Muscle fibers incubated with the antibodies and with 125I-Protein A were subjected to emulsion autoradiography, followed by cytochemical ChE staining. The anti-cloned BuChE antibodies, as well as anti-Torpedo AChE antibodies, created patches of silver grains in the muscle endplate region stained for ChE, under conditions where control sera did not. These findings demonstrate that the various forms of human AChE and BuChE in blood and in neuromuscular junctions share sequence homologies, but also display structural differences between distinct molecular forms within particular tissues, as well as between similarly sedimenting molecular forms from different tissues.

Acetylcholinesterase↗
PubMed1988

Antibodies against enterotoxigenic Escherichia coli in the colostrum isolated from infants with diarrhea.

The role of certain types of Escherichia coli in infectious diarrhea in infants and young children is well known. Infants who are breast-fed are less prone to gastroenteritis during their first year of life. Antibodies against three types of fimbrial antigens (adhesions) of enterotoxigenic E. coli (ETEC) in the colostrum were studied. The hemagglutination inhibition test method was used to detect antibodies against ETEC adhesions, i.e. colonization factors, I and II and fimbria type I. The colostrum of mothers on the 1st and 3rd day post partum was standard for the presence of antibodies. The results show that most of the colostrum samples contained antibodies against adhesions of the types of ETEC that we worked with. This study will enhance the knowledge as to why mothers should breast-feed their babies.

Antibodies, Bacterial↗
PubMed1988

Ethnic variation in estrogen and progesterone receptor concentration in leiomyoma and normal myometrium.

The total content of 17-beta estradiol and progesterone receptors in human uterine leiomyoma and normal myometrium in a Caucasian population was determined. Estrogen receptor concentrations in leiomyoma and myometrium were not significantly different (p = 0.1401). The concentration of progesterone receptors in leiomyoma was higher than in myometrium (p = 0.0303). Negroid and Caucasian ethnic groups did not differ with respect to estrogen (p = 0.7040) or progesterone (p = 0.8494) receptor concentrations in leiomyoma, but estrogen (p less than 0.005) and progesterone (p less than 0.005) receptor concentrations in normal myometrium were significantly higher in Caucasian than in negroid patients. Leiomyoma in negroid and Caucasian patients appears to be histologically similar, but the biochemical pathway of its pathogenesis seems to differ. Genetic predisposition probably acts as an initiation factor in the myometrium of both ethnic groups, then estrogen receptor levels in negroids and alterations in steroid metabolism in Caucasians promote the growth of leiomyoma.

Adult↗
PubMed1988

Ovarian abscess following cesarean section. A case report and review of literature.

Ovarian abscess is presented although such a finding is an unusual gynecologic complication. It is difficult to distinguish from a tubo-ovarian abscess. Its presence may be suspected in a patients after surgery, carrying IUD, having intraperitoneal infection and pregnancy. If an abscess is present, a tubo-ovarian abscess is much more common, except in pregnancy. For the last 110 years only 120 cases of ovarian abscesses have been reported in the Literature.

Abscess↗
PubMed1987

Human cholinesterase genes localized by hybridization to chromosomes 3 and 16.

A cloned human cDNA for cholinesterase (ChE) was used as a probe for in situ hybridization to spread lymphocyte chromosomes to map the structural human CHE genes to distinct chromosomal regions. The recent genetic linkage assignment of the CHE1 locus of the CHE gene to chromosome 3q was confirmed and further refined to 3q21-q26, close to the genes coding for transferrin (TF) and transferrin receptor (TFRC). The CHE1 allele localizes to a 3q region that is commonly mutated and then associated with abnormal megakaryocyte proliferation in acute myelodysplastic anomalies. In view of earlier findings that ChE inhibitors induce megakaryocytopoiesis in culture, this localization may indicate that ChEs are involved in regulating the differentiation of megakaryocytes. A second site for ChEcDNA hybridization was found on chromosome 16p11-q23, demonstrating that the CHE2 locus of the cholinesterase gene, which directs the production of the common C5 variant of serum ChE, also codes for a structural subunit of the enzyme and is localized on the same chromosome with the haptoglobin (HP) gene, both genes being found on the long arm of chromosome 16. The finding of two sites for ChEcDNA hybridization suggests that the two loci coding for human ChEs may include nonidentical sequences responsible for the biochemical differences between ChE variants.

Cholinesterases↗
PubMed1987

Observations on the ultrasound diagnosis of ovarian neoplasms.

In order to determine whether sonography could differentiate between benign and malignant ovarian neoplasms a retrospective analysis of preoperative ultrasound examination was made. The ultrasound images were evaluated for internal consistency, presence of septae, presence of solid nodules, papillary projections and tumor borders. Evidence of ascites and omental involvement were also assessed. Our study showed that benign ovarian serous tumors had a similar appearance to low grade malignant serous tumors, and were undistinguishable from the borderline serous carcinoma. The poorly differentiated serous adenocarcinoma was characterized by the presence of thick papillary projections rather than echogenicity. However, benign or malignant mucinous tumors gave the same pattern. Loss of tumor wall definition, ascites and omental involvement may signal malignancy. The dermoid tumor had a characteristic sonographic appearance.

Adenocarcinoma↗
PubMed1987

Antitumor effects of inhibitors of arachidonic acid cascade on experimentally induced intestinal tumors.

The antitumor action of inhibitors of cyclooxygenase (indomethacin) and lipoxygenase activity (nordihydroguaiaretic acid) of arachidonic acid cascade was investigated in the chemically induced large bowel tumors in Sprague-Dawley rats. Indomethacin treatment completely prevented the carcinogenic effect of methylazoxymethanol. Thus, no tumors were found in the 14 rat test group, compared with 13 of 14 tumor-bearing rats in the untreated control group. Although nordihydroguaiaretic acid treatment does not abolish prostaglandin synthesis, it does reduce the effect of the carcinogen and tumors were found in only five of 14 treated rats. From this study it can be postulated that not only is reduction in prostaglandin formation responsible for the inhibition of tumor growth, but also leukotrienes may play some role.

Animals↗
PubMed1987

Sirenomelia in a twelve weeks abortus.

The anatomical findings of sirenomelia in a 12-weeks aborted embryo are reported. The occurrence of sirenomelia in material from spontaneous abortions is discussed.

Abnormalities, Multiple↗
PubMed1987

Expression of cholinesterase genes in human oocytes revealed by in-situ hybridization.

Transcriptional activity of the human cholinesterase genes was examined in developing oocytes from mature ovaries by in-situ hybridization combined with biochemical acetylcholine hydrolysis measurements. High levels of cholinesterase mRNA could be detected in oocytes from primordial, pre-antral and antral follicles but not in atretic follicles, with transient enhancement at the pre-antral stage. Biochemical analysis of enzymatic activity identified the ovarian enzyme as 'true' acetylcholinesterase by its sensitivity to selective inhibitors. Our findings suggest that cholinergic responses may function in human oocytes independently of the surrounding follicular cells, and the pronounced synthesis of cholinesterase transcripts in oocytes suggests that the cholinesterase genes in humans are particularly good candidates for the formation and re-insertion of inheritable processed cholinesterase genes.

Acetylcholinesterase↗