Regulation of NGF gene expression in CNS glia by cell-cell contact.

Nerve growth factor (NGF) gene expression in central nervous system (CNS) glia appears to be associated with active glial growth. To study the underlying molecular mechanisms, we examined the effects of a number of growth-related factors on NGF mRNA expression in glial cultures. Our results suggest that glial membrane interaction, as a consequence of growth, actively inhibits NGF gene expression in CNS glia.     

A randomized multicenter study to determine the efficacy of activity restriction for preterm labor management in patients testing negative for fetal fibronectin.

OBJECTIVE: To assess the impact of activity restriction (AR) on the incidence of preterm birth in women treated for preterm labor testing negative for fetal fibronectin (fFN). STUDY DESIGN: Women who were diagnosed with preterm labor and tocolyzed with magnesium sulfate were concurrently screened with fFN for the purpose of subsequent management. Included were consenting patients with negative fFN, gestational age 23 0/7-33 6/7 weeks, cervical dilation < or =3 cm, and minimal vaginal bleeding. Patients were randomized to AR or no AR. Primary study outcome was incidence of preterm delivery and interval from randomization to delivery. RESULTS: A total of 73 women with negative fFN were randomized (36 with AR, 37 without AR). The overall preterm birth rate was 40%, with 44.4% of patients with AR and 35.1% of patients without AR delivering preterm, p=0.478. CONCLUSION: Maternal AR did not impact pregnancy outcome. The incidence of preterm birth in symptomatic women testing fFN negative was higher than previously reported.     

Effects of fenfluramine on neuropsychological and communicative functioning in treatment-refractory schizophrenic patients

Reported behavioral improvement among autistic patients following feufluramine treatment and a high serotonin level among certain chronic schizophrenic patients suggested that fenfluramine treatment might be beneficial with such schizophrenic patients, especially within the realm of neuropsychological and communicative functioning. A brief neuropsychological battery was administered to eight chronic schizophrenic subjects before, during, and after fenfluramine treatment. Conversations in controlled settings were audiotaped before and during fenfluramine treatment for seven of these subjects and one additional subject. These language samples were analyzed for communicative competence and evidence of thought disorder. Overall, neuropsychological and communicative functioning was worse under the fenfluramine condition, even though blood serotonin levels were about half those at baseline conditions. The results suggest that it is not the higher levels of blood serotonin by themselves that are related to depressed neuropsychological, communicative, and other functioning. In fact, the higher levels of serotonin may well be related to adaptations for maximal level of functioning. These results suggest caution in the use of fenfluramine for other schizophrenic populations.     

Indicated and non-indicated preterm delivery in twin gestations: impact on neonatal outcome and cost.

OBJECTIVE: To identify the etiology and impact of preterm delivery in twin gestations. STUDY DESIGN: Twin gestations delivered at 33.0 to 36.9 weeks were identified in a perinatal database, and categorized by indication for delivery. Deliveries were identified as indicated, or non-indicated (discretionary). Neonatal outcomes were measured by birth weight, length of stay, NICU admission, and ventilator utilization. Data were divided and analyzed by indicated or discretionary delivery, and gestational age at delivery. RESULTS: Analyzed were 3252 twin gestations (6504 infants), with 78% having indicated delivery. Of the 22% with discretionary delivery, nearly 40% required NICU admission. With each advancing week of gestation, there was a significant decrease in incidence of NICU admission and nursery days. CONCLUSION: The majority of preterm deliveries were indicated, though 22% were discretionary. It is vital to consider neonatal morbidity and costs related to gestational age when choosing discretionary delivery.     

Inactivity of methylene chloride in the mouse bone marrow micronucleus assay

Methylene chloride (MC) has been evaluated for its ability toinduce micronucleated polychromatic erythrocytes (MPEs) in thebone marrow of treated mice. Groups of five male and five femaleC57BL/6J/Alpk mice were exposed, by gavage, to doses of 4000,2500 and 1250 mg/kg MC in corn oil, the highest dose-level beingselected to be the maximum tolerated dose. Bone marrow sampleswere taken 24, 36, 48 and 72 h after dosing. No significantincreases in the incidence of MPEs over controls were observedfor any of the test groups, and it is concluded that MC is notclastogenic in this assay.     

Immunology

A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in immunology.     

Inhibitory effects of AH 21-132 in guinea-pig isolated ileum and taenia caeci.

1. AH 21-132 is being investigated as a potential chemotherapeutic agent for bronchial asthma. The present experiments were designed to determine whether AH 21-132 shares the activity of theophylline as an antagonist at adenosine A1 receptors and to assess its potency as a relaxant in intestinal smooth muscle. 2. In the transmurally-stimulated guinea-pig ileum, theophylline (1 mM), but not AH 21-132 (1 and 10 microM), antagonized twitch depression induced by adenosine. Higher concentrations (100 microM and 1 mM) of AH 21-132 themselves had a depressant effect. Neither theophylline (1 mM) nor AH 21-132 (1 and 10 microM) antagonized twitch depression induced by noradrenaline. 3. AH 21-132 (100 microM and 1 mM) depressed maximum contractions of ileum induced by both acetylcholine (ACh) and histamine. 4. In ileum treated with hyoscine (1 microM), AH 21-132 (greater than 10 microM) caused a concentration-dependent depression of the log concentration-effect curve for potassium chloride. 5. Simultaneous extracellular electrophysiological and mechanical recording from taenia caeci showed that AH 21-132 (100 microM-1 mM) inhibited spontaneous tension waves and their associated bursts of electrical spike activity. 6. Intracellular electrophysiological recording from taenia caeci showed that the mechano-inhibitory effect of 1 mM AH 21-132 was accompanied by abolition of spontaneous spike activity. Following spike abolition, the membrane potential assumed a value very close to that observed during periods of electrical quiescence prior to drug exposure. 7. AH 21-132 inhibited the activity of cyclic AMP-dependent and cyclic GMP-dependent phosphodiesterases derived from homogenates of ileal smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)