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Biomedical subjects

D R Abramovich

Publications and source records attributed to D R Abramovich.

11 recordsLinked to original sources
PubMed1991

Inhibitor action on placental calcium transport.

Human term placental lobules were dually perfused with Krebs Ringer solution at 37 degrees C under open circuit conditions. Provided that perfusate Ca2+ concentrations were between 2.33 and 2.55 mM, there was a steady release of Ca2+ into the fetal circulation and uptake of Ca2+ from the maternal circulation. There was no significant calcium (Ca) protein binding in the perfusates. Addition of dinitrophenol altered the release of Ca2+ to an uptake on the fetal circuit and enhanced Ca2+ uptake on the maternal circuit. It also produced a release of potassium (K)+ and an uptake of Na+ on both sides of the placenta. Ouabain had no significant effect on Ca movements although it produced a marked release of K+ into the fetal perfusate. The effect of cooling on the fetal circuit was similar to that of dinitrophenol (DNP), although it did not produce significant changes in either Ca2+ or K+ movements on the maternal side of the lobule. Both DNP and cooling reduced the Ca concentration ratio between fetal and maternal outflows to unity. Replacement of Na+ by choline Ringer had only transient effect on the extraction of 45Ca from fetal perfusate. These observations indicate that a Ca2+/Na (sodium)+ exchanger does not make a major contribution to the transplacental movement of Ca2+ from mother to fetus and that this process is more probably associated with membrane-bound ATPases.

Adenosine Triphosphatases↗
PubMed1991

Survival assessment of cultured epidermal allografts applied onto partial-thickness burn wounds.

Cultured epidermal allografts (C.E.A.) were applied to 6 partial thickness burns. Biopsies were obtained at intervals between 8-100 days after grafting. In the second week clinical re-epithelialisation of the allografted sites was confirmed histologically. Blood group- and sex-mismatch studies showed that the allografted cells were not present between 8-100 days post-grafting, suggesting that the newly formed epithelium was of host origin.

Adult↗
PubMed1991

The differentiation and proliferation of newly formed epidermis on wounds treated with cultured epithelial allografts.

Fifteen patients, eight with burn or scald wounds and seven with split-thickness donor sites, were treated with cultured epithelial allografts. Skin was obtained from HIV-negative donors undergoing circumcision and sheets of epithelium were cultured using the 3T3 feeder method. Multiple post-operative biopsies were performed at various time intervals and stained with a panel of monoclonal antibodies against cytokeratins, involucrin, transferrin receptor and epidermal growth factor receptor. Fresh cultured epithelial sheets, normal skin, standard treated donor sites and burns treated with autografts were also studied. Cytokeratin-10 expression was not observed at treated sites until 4 weeks post-grafting, when normal suprabasal levels were observed. Cytokeratins 13 and 16, usually observed in highly proliferative states such as psoriasis, were observed in epithelial-treated sites for up to 6 months. Other proliferation markers such as Ki67 and transferrin receptor were only expressed 2-3 weeks post-operatively. Involucrin, a marker of keratinocyte terminal differentiation, was expressed throughout newly formed epidermis until 15 weeks, when the normal pattern of granular expression was observed. These results indicate that although the cultured 'allograft' does not survive, it may modulate the proliferation and differentiation of spontaneously regenerating epithelium.

Adult↗
PubMed1991

Parathyroid hormone-(1-34) peptide activates cyclic adenosine 3',5'-monophosphate in the human placenta.

Dually perfused human term placental lobules were exposed to forskolin, bovine parathyroid hormone (bPTH(1-34)) and human parathyroid hormone related-peptides, hPTHrP(1-34), hPTHrP(67-86)NH2 or PTHrP(107-138) for 15 min in the presence of 3-iso-butyl-1-methyl-xanthine (IBMX); control lobules were exposed to IBMX alone. Homogenates of these tissues were then assayed for cyclic adenosine 3',5'-monophosphate (cyclic AMP) and results normalized per mg of protein. Exposure to forskolin or bPTH(1-34) on both sides, and exposure to bPTH(1-34) at a concentration of 30 nM on the maternal side of the placenta or 120 nM on the fetal side of the placenta, significantly enhanced tissue cyclic AMP production compared with tissue exposed to IBMX alone. Exposure to hPTHrP(1-34), hPTHrP(67-86)NH2 and hPTHrP(107-138) at a concentration of 30 nM on both sides of the placenta had no significant effect upon tissue cyclic AMP production.

Cyclic AMP↗
PubMed1979

Fetal swallowing and voiding in relation to hydramnios.

Fetal swallowing and voiding were measured using colloidal gold and an ultrasonic scanner, respectively. Subjects in the study were in their 38-40th week of pregnancy. Cases were divided into 3 groups: normal, hydramnios, and oligohydramnios. The normal group had a mean swallowing rate of 198 ml/day and a mean voiding rate of 23.6 ml/hr. No significant differences were found among these rates and the corresponding rates in the other 2 groups. It is concluded that mechanisms other than fetal swallowing and voiding can contribute to the control of amniotic fluid volume at term.

Amniotic Fluid↗
PubMed1978

Plasma pregnancy-specific beta1-glycoprotein in complications of early pregnancy.

The prognostic value of a single plasma pregnancy-specific beta1-glycoprotein estimation was assessed in 64 patients admitted with a history of vaginal bleeding between 7 and 19 weeks gestation. A correct prognosis was obtained in a high percentage of cases with either continuing pregnancies or with non-viable pregnancies. In very early pregnancy with a gestation less than 10 weeks, a correct prognosis was obtained in about 75 per cent of cases but serial estimations in this group might improve the prognostic value of the test. The assay proved to be infallible where there was doubt as to whether the subject was pregnant. In the present study, single HPL estimations proved to be less useful in evaluating the outcome of complications of early pregnancy.

Abortion, Threatened↗
PubMed1976

Bulk flows through human fetal membranes.

Bulk water flows across term human amnio-chorion are studied in vitro. The hydrodynamic permeability is found to vary with both hydrostatic and osmotic pressure. The coefficient characterizing flows generated by hydrostatic pressure is substantially larger than that characterizing osmotic flows. The measurements are utilised to predict in vivo bulk flows across the amnio-chorion. These lead to the prediction that at most a flux of 34-83 ml/day may occur across amnio-chorion directed outwards from the amniotic cavity, the principal contribution to this arising from the effects of hydrostatic pressure.

Amnion↗
PubMed1975

The origin of amnitoic fluid lecithin.

Lecithin has been measured in amniotic fluid, pharyngeal aspirate, fetal and maternal plasma and fetal membranes from the same pregnancy. In the amniotic fluid from a term pregnancy 79 per cent of the lecithin is found in the reconstituted precipitate of centrifuged fluid. It is suggested that the lecithin of amniotic fluid may originate from sources other than fetal lung and that lecithin concentration is therefore a measure of overall fetal maturity.

Amniotic Fluid↗
PubMedDate not supplied

Uptake of zinc by human placental microvillus border membranes and characterization of the effects of cadmium on this process.

The uptake of Zinc (Zn) by microvillus border membrane vesicles formed from the trophoblast of term human placentae is markedly increased over brief periods of incubation with much slower increases persisting for up to 2 h of incubation. Zinc is both bound to membrane components and transported into intravesicular osmotically active space. Uptake is saturable, temperature dependent from 4 to 37 degrees C with a Q10 of 1.7, and is inhibited by the sulphydryl agent DTNB. About 20 per cent of the uptake is susceptible to inhibition by Cadmium (Cd) at concentrations from 5 to 50 microM, a significant part of the action of this metal being on the transmembrane component of Zn uptake.

Cadmium↗