Biomedical subjects

O Moran

Publications and source records attributed to O Moran.

61 records · Page 4Linked to original sources

PubMed1990

Adnexal torsion of hyperstimulated ovaries in pregnancies after gonadotropin therapy.

A series of 201 cycles of ovarian hyperstimulation syndrome (OHSS) in 154 women were reviewed. Pregnancy occurred in 75 of 201 cycles. Twelve pregnant women (16%) presented with torsion of hyperstimulated ovary, but only 3 out of 126 patients (2.3%) who did not conceive had torsion. Because diagnosis of adnexal torsion is usually uncertain and surgical intervention is likely to be delayed, these infertile women risk losing their ovaries. The clinical picture of torsion of adnexa in patients with OHSS is presented here. The combination of ovarian enlargement, abdominal pain, nausea, progressive leukocytosis, and anemias might indicate torsion of adnexa. Although during operation the adnexa appears dark, hemorrhagic and ischemic, we suggest that it can be saved by simply unwinding it. In 11 such cases intraoperative unwinding of the adnexa was performed, and in 8 patients it was the only operative procedure. No postoperative complications were noted and in all the cases the ovaries were proven functional by ultrasonography. We concluded that torsion of hyperstimulated adnexa in patients who conceived after gonadotropin therapy, is a special entity that requires more attention to achieve early diagnosis. Nevertheless even with delayed diagnosis, the ovary can still be saved.

Adnexal Diseases↗

PubMed1989

Changes of N-methyl-D-aspartate activated channels of cerebellar granule cells with days in culture.

N-Methyl-D-Aspartate (NMDA) activated channels were studied in enzymatically dissociated cerebellar granule cells primary cultures. Measurements of single channel currents were made on different days in culture. Changes in the electrophysiological behavior of NMDA-activated channels, which were dependent on the time in culture, were found. The variations of single channel maximum conductance during the developement of the cells in culture were detected. Three different characteristic periods could be distinguished: the first period (1-3 days) in which the conductance assumed a value of 15.5 pS; the second one (5-8 days) characterized by a value of 35.7 pS and the last one (9-11 days) in which the conductance reached values of 46.8 pS. Moreover mean open time of NMDA-activated channels was less than 1 msec during the first two days in culture and stabilized at 3 to 6 msec around the fifth day.

Animals↗

PubMed1989

Further investigation on the high-conductance ion channel of the inner membrane of mitochondria.

By use of the patch-clamp technique, the inner membrane of mouse liver and heart mitochondria is shown to contain a highly conductive (around 100 pS in symmetrical 150 mM KCl) and voltage-dependent ion channel. This channel closely resembles that previously found in cuprizone-treated mouse liver inner mitochondrial membrane. The paper discusses the electrical properties of the channel and its possible physiological function. The reconstitution in giant liposomes of a partially purified ox heart inner membrane fraction containing the channel and the use of various inhibitors are also presented.

Animals↗

PubMed1989

Protein kinase C modulates neurotransmitter responses in Xenopus oocytes injected with rat brain RNA.

Oocytes of the frog Xenopus laevis express various exogenous neurotransmitter receptors and ion channels when injected with RNA from excitable tissues. The oocytes serve as a convenient model system in which modulation of neurotransmitter responses can be studied. We examined the effects of activators and an inhibitor of protein kinase C (PKC) on responses to serotonin (5-HT), acetylcholine (ACh), kainate, and gamma-aminobutyric acid (GABA) in oocytes injected with RNA from rat brain. The PKC activators beta-phorbol esters 4 beta-phorbol-12-myristate-13-acetate (PMA) and 4 beta-phorbol-12,13-dibutyrate (PDBu), as well as the synthetic diacylglycerol, 1-oleyl-2-acetylglycerol (OAG), significantly inhibited the responses to 5-HT and ACh (both known to be mediated by mobilization of intracellular Ca2+); the first (transient) phase of these responses was affected stronger than the second, slow phase. PKC activators also reduced the response to GABA. The effect of PDBu on the response to kainate was dual; either inhibition or potentiation were observed at different concentrations of PDBu. The inactive analogue of PMA, the alpha-PMA, was without effect on the responses to 5-HT and GABA. The PKC inhibitor 1,5-isoquinolinesulfonyl-2-methylpiperazine (H7) suppressed the inhibitory effect of PDBu on 5-HT response. Amiloride, a blocker of the Na+/H+ exchange (which is known to be activated by PKC in some tissues), did not suppress the effects of PDBu. We concluded that activation of PKC down-regulates the responses to 5-HT, ACh and GABA, and has a dual effect on response to kainate. Possible mechanisms of these effects are discussed.

Acetylcholine↗

PubMed1987

An X-ray diffraction study of changes in myelin structure during experimental allergic neuritis.

In order to determine whether the structure of the myelin membranes is modified during experimental allergic neuritis (EAN), we have performed X-ray diffraction studies of in vivo and of isolated sciatic nerves from Lewis rats exposed to different EAN-producing treatments. We have observed a decrease of the intensities in the X-ray reflections without changes in spatial resolution. The level of decrease correlated with the severity of the demyelinating lesions. In comparison to nerves from normal healthy rats the electron density profile of sciatic nerve myelin from animals in acute stages of EAN showed small differences at both cytoplasmic and extracellular spaces of the myelin membrane. Dynamic X-ray diffraction patterns recorded kinetically in vivo from a nerve injected intraneurally with a neuritogenic antiserum do not show additional reflections characteristic of a distinct lattice of increased periodicity, suggesting that the early stages of demyelination do not involve an intermediate ordered state.

Animals↗

PubMed1981

Variability of oxygen affinity of blood: human subjects native to high altitude.

Whole blood O2 equilibrium curves (OEC) were measured in 46 Peruvians native to high altitude (4,540 m) and in 25 sea-level controls. A method was employed that records the entire OEC from 0 to 150 Torr with constant pH and PCO2. The data were analyzed by fitting the Adair equation describing the successive oxygenation of hemoglobin. At pH 7.4 the PO2 at which hemoglobin is half-saturated with O2 (P50) was significantly higher in the high-altitude population (31.2 +/- 1.9 Torr) than in controls (29.2 +/- 1.8 Torr, P less than 0.001). The acid-base status of the high-altitude subjects, however, was that of compensated respiratory alkalosis (plasma pH 7.439 +/- 0.065), and when the P50's were corrected to the subjects' plasma pH the values (30.1 +/- 2.2 Torr) could no longer be distinguished from the controls. We conclude that, on the average, increased P50 resulting from increased red cell 2,3-diphosphyoglycerate concentration at high altitude is offset by compensated respiratory alkalosis with the net result that the position of the OEC more closely approaches that of sea-level humans than has hitherto been thought. Considerable variation exists in P50, both at sea level and high altitude. This variation might have important consequences for acclimatization and survival under adverse environmental conditions.

2,3-Diphosphoglycerate↗

PubMedDate not supplied

Development of voltage-dependent ionic currents in rat cerebellar granule cells grown in primary culture.

In this work we studied the excitable properties of cerebellar granule cells grown in primary culture in the presence of "high" KCl (25 mM). Whole cell patch-clamp records of currents were obtained from cells at 1-33 days in culture (DIC). Sodium currents, blocked by TTX, were present from the first DIC and did show slow developmental changes. Two types of potassium currents were detected at all DIC: a delayed rectifier current (IK) and an inactivating current (IA). Both IK and IA increased until 7 to 9 DIC (four and two times respectively). Most of the IA increase, however, correlated with an increase in cell size, monitored by measurements of cell membrane capacitance (Cm) and the current density thus did not change. Conversely, delayed rectifier potassium current density did increase in the initial DIC (3-6) and did not change significantly after this time. Calcium currents were not detectable at any DIC under our experimental conditions.

Action Potentials↗