Activated alpha subunit of Go protein induces oocyte maturation.

The capability of various activated guanine nucleotide binding regulatory protein (G protein) alpha subunits to induce meiotic maturation was studied. Activated Go protein alpha subunit (alpha o*) but not the three inhibitory G protein alpha subunits triggered meiotic maturation in Xenopus oocytes. The effect was concentration dependent with a half-maximal effect in the 100-200 pM range.

Two forms of the bovine brain Go that stimulate the inositol trisphosphate-mediated Cl- currents in Xenopus oocytes. Distinct guanine nucleotide binding properties.

Heterotrimeric GTP-binding proteins from bovine brain were resolved by fast protein liquid chromatography chromatography using Mono Q columns. Two distinct forms of the protein Go were identified. Both forms had stochiometric amounts of alpha- and beta gamma-subunits.

Blood pressure in Ethiopian immigrants: relationship to age and anthropometric factors, and changes during their first year in Israel.

Blood pressure was measured in 483 Ethiopian immigrants during the first week following their arrival in Israel. Mean levels of diastolic (DBP) and systolic blood pressures (SBP) were very low compared with known levels in the Israeli population. BPs were elevated in men greater than 20 years old and in women greater than 40 years old.

Fatty acid composition of adipose tissue in Ethiopian immigrants: a prospective study during their first year in Israel.

We measured the subcutaneous adipose tissue fatty acid composition in 22 male Ethiopian Jews, aged 17-65, shortly after their immigration to Israel. These subjects showed a concentration of linoleic acid (17.8%), which was relatively low compared with Israeli levels, and a high concentration of palmitic acid (28.

Prevalence of diabetes mellitus in Ethiopian immigrants.

The prevalence of diabetes mellitus among 445 new immigrant Ethiopian Jews was studied immediately after their arrival to Israel, and found to be 0.4%. This low prevalence could be attributed to their long trek accompanied by severe malnutrition which caused death to the old, weak and sick, leaving a selectively young and healthy population group.

Nifedipine blocks calcium-dependent cholinergic depolarization in the guinea pig hippocampus.

The possibility that cholinergic stimulation might directly activate a receptor-operated Ca2+ channel was investigated in the CA1 region of guinea pig hippocampus using intracellular recording techniques. Two cholinergic responses were studied: (1) the plateau depolarization evoked by cholinergic stimulation in the presence of Ba2+; and (2) the Ca2(+)-dependent component of membrane depolarization. Both of these responses were blocked by 1-5 microM of nifedipine, a blocker of voltage-dependent L-type Ca2+ channels.

[Extracorporeal shock wave lithotripsy for cystine urolithiasis].

We present 31 patients with cystine urolithiasis referred to our extracorporeal shock wave lithotripsy (ESWL) center since 1985. This group differed statistically from the other 3000 patients treated by us for urolithiasis with regard to age, stone burden, number of previous operations, and known duration of urolithiasis. The average known duration in those with cystine stones was 15 years.

Long-term potentiation in rat hippocampus is inhibited by low concentrations of ethanol.

Acute ethanol ingestion impairs memory in humans at concentrations associated with mild intoxication. A possible neurophysiological correlate of this effect is the suppression by ethanol of long-tem potentiation (LTP), a persistent increase in synaptic efficiency which has been proposed as a substrate for memory. However, in previous studies ethanol has been shown to impair LTP only at very high concentrations, near the lethal level in humans.

Cholinergic stimulation enhances long-term potentiation in the CA1 region of rat hippocampus.

The effect of the cholinergic agonist carbachol on a putative substrate for memory (long-term potentiation; LTP) was investigated in slices of rat hippocampus (CA1 region). Carbachol (5 microM) increased LTP when the presynaptic depression of the EPSP was controlled. The results indicate that carbachol enhances the effectiveness of the tetanus, probably through postsynaptic mechanisms.

A biophysical study of abscisic acid interaction with membrane phospholipid components.

Molecular area/surface pressure Langmuir isotherms of amphiphilic dipalmitoylphosphatidylcholine (DPPC) monolayers indicated that abscisic acid (ABA) has a marked rigidifying effect, expressed as reduction of molecular area and increase of monolayer collapse point. Moreover, ABA markedly increased aqueous droplet hydrophobicity, as indicated by a concentration-dependent increase of contact angle when placed on a hydrocarbon chain surface; no such effects were obtained on either amphiphilic or octadecyltrichlorosilane surfaces. A combination of TLC and mass spectometry revealed the presence of DPPC in Vicia faba and Commelina communis guard-cell protoplast membranes.

Treatment of uncontrolled hemorrhagic shock with hypertonic saline solution.

Hypertonic saline solution (HTS) treatment of uncontrolled hemorrhagic shock (UCHS) induced by incision of three major branches of the ileocolic artery, leading to free intra-abdominal bleeding, was studied in rats. The rats were divided into two groups. In group 1, the abdominal wall was closed immediately after induction of hemorrhage and the rats were divided into six subgroups--1a, five untreated; 1b, 14 treated with 5 milliliters per kilogram of sodium chloride 7.

Effect of leukotriene inhibitor LY-171883 on the pulmonary response to Escherichia coli endotoxemia.

The effect of the leukotriene D4 (LTD4) receptor antagonist, LY-171883, on the respiratory and cardiovascular changes in endotoxemia was studied in 20 unanesthetized sheep. In group 1 (n = 2), 4 mg/kg LY-171883 was injected iv. In group 2 (n = 12), Escherichia coli endotoxin (1 micrograms/kg) was infused iv, and in group 3 (n = 6), 4 mg/kg LY-171883 was administered 15 min before and 30 min after the same dose of endotoxin.

Go protein as signal transducer in the pertussis toxin-sensitive phosphatidylinositol pathway.

Receptors stimulating phospholipase C do so through heterotrimeric GTP-binding proteins to produce two second messengers, inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol. In spite of the detailed understanding of phospholipase C structure and phosphatidyl inositol signalling, the identity of the GTP-binding protein involved is so far unknown. To address this issue, we have used the Xenopus oocyte in which muscarinic receptors couple to phospholipase C through a pertussis toxin-sensitive GTP-binding protein.

Gonadotropin-releasing hormone receptor expression in Xenopus oocytes.

The rodent GnRH receptor was characterized in Xenopus oocytes injected with RNA isolated from rat pituitary and from a gonadotrope cell line, alpha T3, derived from a transgenic mouse. Three to 4 days after 150-200 ng RNA injection, 93% of the oocytes, which were recorded by voltage clamp, responded to 10(-7) M GnRH. The mean inward currents obtained after RNA injection were 620 +/- 88 nA (n = 22) with pituitary RNA and 1415 +/- 598 (n = 4) with alpha T3 RNA.

Treatment of uncontrolled hemorrhagic shock by hypertonic saline and external counterpressure.

The effect of an external counterpressure device (ECPD) on hypertonic saline treatment of uncontrolled hemorrhagic shock (UCHS) was studied in rats. The rats were divided into five groups. In group 1 (n = 11) UCHS induced by incision of three radicals of the ileocolic artery was treated by 5 mL/kg NaCl 0.

A novel calcium-dependent chloride current in Xenopus oocytes injected with brain messenger RNA.

1. Membrane currents were studied in voltage-clamped Xenopus laevis oocytes which had been injected with total rat brain RNA. 2.

Coupling of exogenous receptors to phospholipase C in Xenopus oocytes through pertussis toxin-sensitive and -insensitive pathways. Cross-talk through heterotrimeric G-proteins.

Heterotrimeric guanine nucleotide-binding proteins (G-proteins) can be categorized into molecularly divergent groups by their differential sensitivity to pertussis toxin. Receptors specifically use either pertussis toxin-sensitive or-insensitive G-proteins to couple to specific effectors. Receptor stimulation of phospholipase C, however, is pertussis toxin sensitive in some systems and pertussis toxin insensitive in others.

Isolated pulmonary blast injury in rats--a new model using the extracorporeal shock-wave lithotriptor.

Blast injury to the lungs is one of the most overwhelming threats to survival following exposure to powerful explosions. The pathophysiology of blast injuries differs significantly from other forms of trauma. Using the extracorporeal shock-wave lithotriptor, originally designed for the noninvasive treatment of nephrolithiasis, we were able to produce isolated, typical pulmonary blast effects in rats.

Ethanol suppresses hippocampal cell firing through a calcium and cyclic AMP-sensitive mechanism.

The effects of ethanol were studied intracellularly in hippocampal pyramidal cells in vitro. Ethanol, 50-100 mM, produced a marked suppression of neuronal firing. This effect was blocked by treating the cell with cyclic 3', 5'-adenosine monophosphate (cAMP) or cadmium ions.

Functional muscarinic supersensitivity in denervated rat hippocampus.

The effects of carbachol (CCh), a cholinergic agonist, were compared in voltage-clamped hippocampal pyramidal neurons in vitro, obtained from normal and fimbria-fornix-lesioned rats. A substantial increase in sensitivity to the effects of CCh was seen in denervated neurons. The supersensitivity was demonstrated on both the inward leak current and the calcium-dependent potassium current, IAHP.

Quantitative measurement of bleeding following hypertonic saline therapy in 'uncontrolled' hemorrhagic shock.

The effect of small volume hypertonic saline in "uncontrolled" hemorrhagic shock (UCHS) induced by partial resection of the tail was studied in rats. The rats were divided into three groups: in group 1 (n = 15) 10% of the terminal portion of the animal's tail was resected to induce UCHS. In group 2 (n = 14) UCHS was induced as in group 1 and after 5 min 5 ml/kg NaCl 0.

Intestinal obstruction caused by bezoar: a rare complication after bone marrow transplantation.

Gastrointestinal complications are described frequently after preparation of patients for bone marrow transplantation (BMT). Two patients who underwent BMT developed complications due to gastrointestinal bezoars. One patient developed intestinal obstruction, which necessitated emergency surgery, and the other patient had a gastric bezoar, which caused vomiting.

A Synchrotron X-ray Study of a Solid-Solid Phase Transition in a Two-Dimensional Crystal.

A measurement and interpretation on a molecular level of a phase transition in an ordered Langmuir monolayer is reported. The diagram of surface pressure (pi) versus molecular area of a monolayer of chiral (S)-[CF(3)-(CF(2))(9)-(CH(2))(2)-OCO-CH(2)-CH (NH(3)(+))CO(2)(-)] over water shows a change in slope at about pi(s)= 25 millinewtons per meter. Grazing-incidence x-ray diffraction and specular reflectivity measurements indicate a solid-solid phase transition at pi(s).

Beta gamma subunits of GTP-binding proteins inhibit muscarinic receptor stimulation of phospholipase C.

This study examines the mechanism of guanine nucleotide-binding protein (G protein) coupling of receptors to phospholipase C. The Xenopus oocyte has a muscarinic receptor-activated Cl- current that is mediated by inositol 1,4,5-trisphosphate. Modulation of the muscarinic receptor-evoked Cl- current was examined under voltage clamp in oocytes injected with resolved G-protein subunits.

Activation of ionic currents in Xenopus oocytes by corticotropin-releasing peptides.

Oocytes of the African frog Xenopus laevis are shown by electrophysiological methods to possess receptors for corticotropin-releasing factor (CRF), arginine-vasopressin (AVP) and cholecystokinin (CCK). Oocytes surrounded by their follicular cell envelope responded to CRF or AVP with an outward hyperpolarizing current. This current was mediated by an increased conductance of K+ ions.