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Biomedical subjects

S Elias

Publications and source records attributed to S Elias.

At least 199 records · Page 11Linked to original sources
PubMed1980

Stability of sex chromosome mosaicism.

In individuals with sex chromosome mosaicism the proportions of cell lines have been reported to change over time; however, purported changes have failed to show a consistent decrease or increase in any given cell line, normal or abnormal. We, therefore, investigated three mosaic individuals: two 45,X/46,X,i(Xq) and one 45,X/46,XX. We first initiated studies which verified that the proportion of various cell lines can be reliably (reproducibly) quantitated in lymphocytes of mosaic individuals, data which surprisingly were heretofore unavailable. Having established the ability to quantitate sex chromosome mosaicism, we initiated longitudinal studies. No significant differences in proportions of mosaic cell lines were observed in the three individuals studied over various time intervals. This stability was observed in individuals with high as well as lower proportions of 45,X cells. Further studies over longer periods and with other subjects are continuing, but our preliminary studies suggest mosaicism shows longitudinal stability, at least in adults. The practical clinical significance is that mosaicism can be reproducibly quantitated from a single lymphocyte culture, indicating that a single blood sample will generally suffice for most clinical studies.

Adolescent↗
PubMed1980

ATP-dependent conjugation of reticulocyte proteins with the polypeptide required for protein degradation.

The heat-stable polypeptide (APF-1) required for ATP-dependent proteolysis in reticulocytes enters into high molecular weight conjugates upon incubation with the fraction of reticulocytes that is retained by DEAE-cellulose. Conjugate formation requires ATP and Mg2+ and its inhibited by N-ethylmaleimide. UTP and GTP are inactive. These properties are identical to those of ATP-dependent protein breakdown in the same system, suggesting that the conjugates are intermediates in this process. The APF-1 conjugates are stable in sodium dodecyl sulfate/polyacrylamide gel electrophoresis and Sephadex G-75 isolation and are resistant to mild acid, alkali, heat denaturation, and reduction; the conjugates are therefore covalent.

Adenosine Triphosphate↗
PubMed1980

Prenatal diagnosis of harlequin ichthyosis.

We report the successful prenatal diagnosis of ichthyosis in the fetus of a woman whose previous liveborn child was affected with "harlequin ichthyosis". The fetal diagnosis was established through analysis of ultrasonographically guided fetoscopic skin biopsies. These biopsies showed premature hyperkeratosis, most marked around hair follicles and sweat ducts, and forming plugs of hyperkeratotic debris. These observations were in distinct contrast to those in control fetuses, whose epidermis consists of squamous epithelium only a few cells in depth with minimal keratinization.

Adult↗
PubMed1980

Cancer mortality in a human isolate.

Cancer mortality (1965--77) among 12,652 members of an inbred human religious isolate, the Hutterites, was compared with expectations based on mortality rates for the U.S. white population in 1970. Overall, Hutterites had significantly fewer deaths from cancer than expected (P < 0.01), due primarily to fewer lung cancers among males. Smoking is prohibited for this religious group. The most frequent types of cancers were leukemia and cancers of the digestive system, the prostate gland, and the female breast. Preliminary results suggest an association between recessive alleles and childhood leukemia. More stomach and rectal cancers were observed than expected, but differences were generally not significant. Familial aggregates of cancers of the stomach and breast are being investigated. The low frequency of cervical cancer is consistent with current evidence for an association of cervical cancer with early age at first intercourse and promiscuity, neither of which is characteristic of this population.

Canada↗
PubMed1980

Amniocentesis for antenatal diagnosis of genetic defects.

Amniocentesis for intrauterine diagnosis of genetic disease is a safe and highly accurate procedure. This is most fortunate since the timing of the procedure (14 to 16 weeks) and the length of time necessary to cultivate the cells and perform the analysis (3 to 5 weeks) makes it almost mandatory, and almost unique in medicine, that patient management be based on a single non-repeated laboratory procedure. It should be recommended to all patients for whom there is a specific indication for antenatal genetic studies.

Adult↗
PubMed1980

The role of fetoscopy in antenatal diagnosis.

The application of fetoscopy has been limited thus far, but many uses can be envisioned for the future. Fetal blood sampling via fetoscopy provides information concerning haemoglobinopathies, various enzymatic activities, immunological competence, and haematological status. In addition to direct visualization for fetal malformations, fetoscopy could prove useful for intrauterine therapeutics. For example, intrauterine transfusion under direct visualization would allow earlier treatment of Rh-sensitized erythroblastoic fetuses, and administration of pharmacological agents and nutrients seems feasible.

Creatine Kinase↗
PubMed1979

Localization of the nucleolar organizer by computer-aided analysis of a variant no. 21 in a human isolate.

A variant chromosome no. 21 consisting of two stalks and two satellites in tandem was detected during a survey of a human isolate. The variant segregated in three generations of a large kindred. One male had the variant no. 21, a metacentric Y, and a 47,XXY complement; however, no other evidence of chromosomal nondisjunction was found. Computer-aided analysis of sequentially stained variant no. 21 chromosomes indicated that silver-stained material corresponded to the proximal stalk region (as defined by Giemsa), but often covered both the distal stalk and satellite (also as defined by Giemsa). These data support the hypothesis that human nucleolar organizers are localized to the stalks of acrocentric chromosomes.

Azure Stains↗
PubMed1979

Analysis for amniotic fluid crystallization in second-trimester amniocentesis.

A potential complication of second-trimester amniocentesis for genetic indications is inadvertent needle insertion into the maternal bladder, resulting in aspiration of urine rather than amniotic fluid. Amniotic fluid forms a characteristic crystalline arborization pattern when allowed to air dry. We utilized this property of amniotic fluid to distinguish amniotic fluid from maternal urine. In 24 of 25 cases studied in a randomized blind fashion the crystalline arborization test correctly identified amniotic fluid, whereas none of the 25 urine samples showed this pattern. Our study indicates that the crystalline arborization test is reliable in distinguishing amniotic fluid from maternal urine during the second trimester of pregnancy.

Amniocentesis↗
PubMed1978

Comparative effects of tritiated water and thymidine on the preimplanted mouse embryo in vitro.

Preimplanted mouse embryos were cultured in an in vitro-system from the two cell stage to blastocysts. In the control cultures about 92% of the incubated embryos developed to blastocysts. When tritiated compounds like tritiated water or tritiated thymidine were present in the incubation medium the number of blastocysts decreased with increased medium tritiated thymidine was about one thousand times more effective than tritiated water. Tritiated thymidine caused a more pronounced division delay than tritiated water which had a strong effect on the blastulation process. Further studies showed that the incorporation of tritiated thymidine into the DNA lead to high concentrations of tritium in the cell nucleus. Dose calculations are performed for the cell nucleus in the case of incubation with tritiated thymidine as well as with tritiated water. The different action of the tritiated compounds can apparently be explained by the specific incorporation of thymidine into the DNA.

Animals↗
PubMed1977

Accelerated degradation of acetylcholine receptor from cultured rat myotubes with myasthenia gravis sera and globulins.

Altered geometry of the neuromuscular junction and a decreased number of acetylcholine receptors appear responsible for the defect of neuromuscular transmission in myasthenia gravis. We have used cultured rat myotubes as a model to study in vitro the potential role of myasthenic globulins in the pathological process. Acetylcholine receptor content was assayed by the extent of 125I-labeled alpha-bungarotoxin binding, and acetylcholine receptor function was assayed by the sensitivity to acetylcholine iontophoresis. The half-life of the acetylcholine receptor was 18.5 hr in the presence or absence of control sera. Myasthenic sera and globulins produced a gradual reduction in acetylcholine receptors, as assessed by biochemical and electrophysiological techniques. The half-life in the presence of myasthenic sera was 6 hr. The accelerated turnover was unaffected by puromycin but was slowed by lowered temperature (18-20 degrees), interference with energy metabolism (2,4-dinitrophenol), and interference with cytoskeletal structures (colchicine and cytochalasin B). We found no electrophysiological evidence to suggest globulin blockade of acetylcholine access to the acetylcholine receptor. Our observations suggest that circulating globulins in myasthenia gravis may contribute to the functional defects of neuromuscular transmission by accelerating the rate of internationalization and degradation of surface membrane acetylcholine receptors.

Acetylcholine↗
PubMed1976

The Marfan syndrome and pregnancy.

The patient described had the Marfan syndrome complicated by a 22-week pregnancy. Because pregnancy potentiates the cardiovascular complications of aortic aneurysm or dissection and there is a 50% risk of having a child afflicted with the disorder, this pregnancy was electively terminated by hysterotomy along with a bilateral tubal ligation. The risks of pregnancy to a woman with the Marfan syndrome are reviewed. The rationale for the method of pregnancy termination chosen is discussed.

Abortion, Therapeutic↗
PubMed1975

Expression of H-Y antigen in human males with two Y chromosomes.

To determine whether the gene that controls the expression of H-Y ("male") antigen on human cells is Y-linked, we have compared the H-Y antigen level in normal males with that in three males with two Y chromosomes. Leukocytes from one XXYY and two XYY males express more H-Y antigen than leukocytes from normal XY males. We conclude that a structural gene or positive regulatory gene for H-Y antigen is on the human Y chromosome. Testing for the H-Y antigen may be of benefit in patients who have signs of masculinization but who lack an identifiable Y chromosome. Positive results for the H-Y antigen would be tentative evidence that the corresponding region of the Y chromosome was present, perhaps as part of a translocation, despite the absence of a typical Y chromosome.

Absorption↗