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Biomedical subjects

N Gleicher

Publications and source records attributed to N Gleicher.

At least 181 records · Page 10Linked to original sources
PubMed1984

Studies of natural killer cells in pregnancy. II. The immunoregulatory effect of pregnancy substances.

This study was performed utilizing a standard 51Cr-release cytotoxicity and a single cell assay against K-562 NK-sensitive target cells. Pregnancy sera and amniotic fluids, were found to decrease human natural killer (NK) activity. Pregnancy sera were able to inhibit overall NK activity of partly purified peripheral blood lymphocytes in a dose dependent fashion. However, the exposure of effector cells to concentrations higher than 20% did not further increase the serum's suppressive activity. Sera taken from preeclamptic pregnancies had a similar inhibitory effect as those from normal pregnancies. Amniotic fluid was found to be even more suppressive than pregnancy serum. Using a single cell cytotoxicity assay we determined that neither serum nor amniotic fluid affected potentially cytotoxic target binding cells ("pre"-NK). The relative number of conjugates with dead target was, however, significantly depressed under the influence of pregnancy serum and to an even greater extent by amniotic fluid. Both pregnancy substances were also able to decrease the number of conjugates with dead target in an interferon-augmented population of lymphocytes. Our investigation indicates that the suppressive effect of amniotic fluid and pregnancy serum on NK activity is based on a blocking effect exerted at the killing capability of the active NK cells.

Amniotic Fluid↗
PubMed1983

Immunology of pregnancy.

Even though the paradox of the fetal allograft is still not completely understood, advances in reproductive immunology have made various immunological mechanisms apparent which seem to play a part in the tolerance of the fetal allograft by a seemingly normal maternal immune system. Pregnancy immunology is, however, not only restricted to the understanding of the transplant analogy of pregnancy, but has also achieved clinical significance through our increased awareness of immunological mechanisms being implicated in various pregnancy disorders. A review is presented outlining our present understanding of both basic immunological mechanisms and the normal process of pregnancy as well as those abnormal mechanisms which may be implicated in pathological states.

Antigen-Antibody Complex↗
PubMed1983

Activity of natural killer cells in normal pregnancy and edema-proteinuria-hypertension gestosis.

Natural killer cytotoxicity of peripheral blood lymphocytes in normal pregnancy and edema-proteinuria-hypertension (EPH) gestosis was investigated and compared to natural killer cytotoxicity in lymphocytes of normal nonpregnant control donors. These lymphocytes were also compared for their ability to respond to interferon treatment in vitro. Natural killer activity was found to be only slightly decreased in normal pregnant women but was found to be increased in patients with EPH gestosis. Interferon treatment of peripheral lymphocytes caused strong enhancement of natural killer activity in lymphocytes of normal pregnant women but resulted in only weak activities in lymphocytes from patients with EPH gestosis. We consequently concluded that pre-natural killer lymphocyte subpopulations from patients with EPH gestosis have already been activated by a presently still unknown stimulator.

Adult↗
PubMed1983

Immunoregulatory mechanisms in pregnancy. II. Further characterization of suppressor lymphocytes induced by alpha-fetoprotein in lymphoid cell cultures.

Nonspecific suppressor cell (SPC) activity has been induced in vitro by preculturing splenocytes from normal mice in the presence of mouse amniotic fluid (MAF) and alpha-fetoprotein for 5 days or more. In adoptive transfer experiments in vivo, these AFP-precultured SPC were shown to reduce the humoral response of mice to sheep red blood cells and the cell-mediated cytotoxic response to allogeneic tumor cells. In mixing experiments in vitro, using freshly explanted splenocytes, the AFP-precultured splenocytes abrogated the generation of specific cytotoxic T-lymphocytes in primary mixed lymphocyte-tumor cell cultures. Supernatants of such precultured cells had at best only a marginal effect. These suppressor cells were found to be nylon-wool nonadherent and their effect could be almost completely abolished by treatment with anti-Thy-1, 2 serum plus complement. SPC precursors were found to be sensitive to cyclophosphamide (in vivo) and to hydrocortisone (in vivo and in vitro). At the same time, they are resistant to different doses of radiation.

Animals↗
PubMed1983

Developmental changes of components of the red cell immune system in the rabbit.

Red cell immune adherence (RCIA) occurs not only in primates but also in nonprimates such as the rabbit. We utilized the rabbit as an animal model to study developmental changes in the immune functions of rabbit red cells. Significant differences between adult and newborn rabbits were found. RCIA-receptor activity of the newborn rabbits was significantly larger than that of adult rabbits (p less than 0.0005). Serum RCIA inhibiting factor, which completely prevented any detectable RCIA, was evident in about 40% of adult but not in any of the newborn rabbits (p less than 0.01). RCIA-inhibiting factor was also detectable in three out of eight pregnant rabbits but did not cross the placenta into the rabbit fetus. High concentrations (33%-100%) of most adult sera but not of newborn sera inhibited RCIA (p less than 0.001). It is suggested that, like the thymus, red cell immune function may reach its peak activity during early developmental periods. The red cell immune function may be essential for the removal of antigen-antibody complement complexes from the fetal circulation and may participate in the activation of T suppressor cells which adhere to autologous red cells.

Age Factors↗
PubMed1983

Direct diagnosis of unruptured ectopic pregnancy by real-time ultrasonography.

Real-time sonography was used in a prospective study of 32 patients as the sole diagnostic parameter for ectopic pregnancy. The minimal finding for diagnosis was an identifiable gestational sac with a circular pattern of echoes. Neither the presence or absence of an intrauterine sac nor the knowledge of either a positive or negative pregnancy test was used in the diagnosis. Among the 32 study patients, the diagnosis of ectopic pregnancy was made by sonography in nine (28.4%). Follow-up surgery confirmed the diagnosis in eight (89%). Among 23 patients with negative findings on sonography, only one was found on follow-up to have an ectopic pregnancy, for a 96% diagnostic accuracy for the negative group. Thus, of 32 patients with the potential diagnosis of ectopic pregnancy, 30 (94%) were correctly diagnosed using real-time sonography alone.

Female↗
PubMed1982

Physician bias in cesarean sections.

Various aspects of physician bias in the decision to perform a cesarean section were investigated by comparing indications for cesarean sections for 1979 and 1980 and investigating the distribution of indications according to the day of the week. The contention that obstetricians may perform cesarean sections on weekends for secondary gain was refuted by showing no difference in the distribution of nonelective cesarean section indications between weekdays and weekends. Statistically significant changes in cesarean section indications were, however, observed between the two investigated years, which may be attributed to an organizational change within the department toward more sophisticated obstetric care. These changes included a significant increase in cesarean sections for dystocia and breech presentation and a decrease for fetal distress and "other" indications. Because the total cesarean section rate did not change during the study periods, it is suggested that modern obstetric practice per se does not increase cesarean section rates, but may shift the distribution of indications for cesarean section.

Attitude of Health Personnel↗
PubMed1982

Immune complexes in pregnancy. III. Immune complexes in immune complex-associated conditions.

Seventeen patients during the third trimester of pregnancy with associated immune complex disease and/or immune complex state and their infants' cord blood were investigated for the presence of immune complexes. In comparing maternal levels of immune complex in normal third-trimester pregnancies to the study group, no statistical significant difference was noted. However, levels in cord blood were significantly lower (p less than 0.0025) than levels in paired maternal samples, but were found to correlate significantly (p less than 0.002). On the basis of the immunochemical analysis of selected pairs, the conclusion is that IgG-containing immune complexes may be responsible for this observed correlation and may represent the normal physiologic situation of pregnancy, whereas IgM-containing immune complexes may represent pathologic, and, therefore, abnormal, states. The suggestion is that the presence of such IgM-containing immune complexes may become predictive of fetoplacental compromise.

Antigen-Antibody Complex↗
PubMed1982

Meperidine-induced sinusoidal fetal heart rate pattern and reversal with naloxone.

A case of sinusoidal fetal heart rate (FHR) pattern in association with maternal intrapartum administration of meperidine is presented. The sinusoidal pattern was reversed after maternal intrapartum administration of naloxone. The significance of this problem and the management of patients with sinusoidal FHR are discussed. The conclusion is reached that iatrogenic causes may at times precipitate a sinusoidal FHR pattern and conservative management may be appropriate.

Electrocardiography↗
PubMed1981

The red-cell immune system.

It is suggested that red cells have an immune function as well as a respiratory one. Adherence of red cells to antigen-antibody-complement complexes (red-cell immune adherence) has been observed in primates and in rabbits and may represent a basic immune phenomenon that is common to at least all mammals. It is estimated that 95% of C3b receptors in the human circulation are located on red cells and that an antigen-antibody-complement complex has a 500-1000 times greater chance of being removed from the circulation by a red cell than by a white cell. That red cells also adhere to autologous thymocytes and T cells suggests that they may act as intermediaries bringing antigens and T cells together.

Animals↗