Baf60c is a component of the neural progenitor-specific BAF complex in developing retina

Remodeling of the chromatin network plays an important role regulating embryonic development as well as differentiation. The SWI/SNF complex is an ATP-dependent chromatin-remodeling complex. It consists of several proteins, including an ATPase subunit, either Brg1 or Brm. Two subunits of this complex, Baf53a and Baf45, have been previously identified as being neural progenitor-specific. In this study, we show that Baf60c, another important part of this large complex, acts in a similar neural progenitor-specific manner. We show that during development Baf60c is expressed in neural progenitors in human retinas as well as mouse retina, cortex and spinal cord. Baf60c expression is lost during neural differentiation and its overexpression keeps the progenitors in a proliferative state through its interaction with the Notch pathway. Finally, we show that Baf60c is re-expressed in the Müller glial cells that re-enter the cell cycle after neurotoxic damage.     

Effects of Gravity-Facilitated Traction on lntervertebral Dimensions of the Lumbar Spine*

The purpose of this study was to determine the effects of gravity-facilitated traction (inversion) on intervertebral dimensions of the lumbar spine. Fifteen normal male subjects were fully inverted for a period of 10 minutes. Vertebral separation was measured on lateral roentgenograms both pre- and postinversion by outlining the margins of the intervertebral bodies both anteriorly and posteriorly and the greatest vertical heights of the intervertebral foramina. Fine point engineering calipers were used to facilitate measurements. A student t-test for paired data was used to determine significance of separation between lumbar segments, following 10 minutes of inversion. The alpha level was set at 0.05 for statistical significance. Gravity-facilitated traction produced increased separation at all levels measured. Significant increases in total mean anterior separation, total mean posterior separation, and total mean intervertebral foraminal separation were determined. Mean anterior separation was significant at all levels except L3-L4. Mean posterior separation was significant at all levels except L1-L2 and L5-S1. Mean intervertebral foraminal separation was significant at all levels but L5-S1. If increases in intervertebral dimensions play a role in the relief of low back syndrome, then gravity-facilitated traction may be an effective moda1i;y in the treatment of this condition. J Orthop Sports Phys Ther 1985;6(5):281-288.     

Sodium regulation of agonist and antagonist binding to β-adrenoceptors in intact and Ns-deficient membranes

Summary Agonist binding to various hormone receptors mediating adenylate cyclase inhibition is decreased by sodium ions. We studied the influence of Na⁺ on agonist and antagonist binding to -adrenoceptors in membrane preparations of guinea pig lung, S49 lymphoma wild-type cells (WT) and their N_s-deficient cyc^– variants by measuring binding of the antagonist, [¹²⁵I]iodocyanopindolol ([¹²⁵I]CYP). At 37° C, sodium decreased the receptor affinity for the agonist, isoproterenol, in all three membrane preparations. In lung and WT membranes, Na⁺ steepened the shallow agonist competition curves in a manner similar to and synergistic with guanine nucleotides. When binding was performend at 4° C, sodium regulation but not guanine nucleotide regulation of agonist binding was preserved. At the low temperature, [¹²⁵I]CYP affinity was reduced, and sodium increased [¹²⁵I]CYP binding in both N_s-containing and N_s-deficient membranes by increasing the antagonist affinity without significant change in total receptor number. Compared to Na⁺, Li⁺ and K⁺ were much less potent and efficient in decreasing agonist and increasing antagonist binding. Na⁺ and Mg²⁺ had opposite effects on agonist binding in the N_s-containing lung and WT membranes but not in the N_s-deficient cyc^– membranes. The data indicate that sodium not only regulates binding of inhibitory hormone receptors but also agonist and antagonist binding to the adenylate cyclase stimulatory -adrenoceptor. The finding that sodium regulation of -adrenoceptor binding is also observed in the N_{s 2} cyc^– membranes, furthermore, indicates that the target of sodium is not the -subunit of N_s but possibly a component common to both types of receptor systems regulating adenylate cyclase activity.     

Fertilization and pregnancies following intracytoplasmic injection of testicular spermatozoa

Purpose Intracytoplasmic injection (ICSI) with testicular sperm was performed in 16 couples. All men had ductal obstruction and failed previous attempts of epididymal sperm microaspiration.Methods Testis tissue was obtained by excisional biopsies and incubated in HEPES buffered EBSS medium over 24 h at 37C. Motile sperm (Grade 1 to 2) were recovered in 13 patients and fertilized a total of 62 oozytes. Four pregnancies were achieved.Results One healthy boy and two girls (twin pregnancy) were born.Conclusions The ongoing pregnancies revealed no fetal abnormalities on ultrasound scanning.Presented at the IXth World Congress on In Vitro Fertilization and Alternate Assisted Reproduction, April 3–7, 1995, Vienna, Austria.     

Oral session 1 — Multiple sclerosis (1)

Oral Sessions

Oral session 1 — Multiple sclerosis (1)     

Evidence against a role of nitric oxide in the indirect negative inotropic-effect of M-cholinoceptor stimulation in human ventricular myocardium

Nitric oxide (NO) has been reported to mediate several effects in response to muscarinic cholinergic stimulation in cardiovascular tissues. Recently, an attenuation of guinea pig cardiac myocyte contraction by NO has been described. The aim of the present study was to determine whether the indirect negative inotropic effect of M-cholinoceptor stimulation in human myocardium is in part due to an effect of endogenous NO. Therefore, the effect of carbachol was studied under control conditions and during inhibition of NO-synthase by pretreatment with N^G-monomethyl-l-arginine (NMMA). Functional experiments were performed in isolated, electrically driven (1 Hz, 37°C) left ventricular papillary muscle strips of human myocardium. Since cytokines have been reported to be increased in the serum of patients with heart failure and could induce NO-synthase activity in failing myocardium, we compared samples from nonfailing and terminally failing (classified as NYHA IV) hearts. The indirect negative inotropic effect of carbachol (10 mol/l) was studied in the presence of the \-adrenoceptor agonist isoprenaline (0.03 mol/l).After stimulation with isoprenaline, carbachol significantly (P < 0.05) reduced force of contraction. This effect was diminished in failing myocardium compared to nonfailing, probably due to the diminished inotropic response most likely due to the lower cAMP levels in response to \-adrenoceptor stimulation in the former condition. Pretreatment with NMMA (100 mol/l) altered the antiadrenergic effect of carbachol neither in nonfailing nor in failing preparations. Furthermore, inhibition of guanylyl cyclase, the target enzyme of NO, by preincubation with methylene blue (10 mol/l) for 30 min had no effect on the carbachol-induced decrease in force of contraction. Basal force of contraction, as well as the positive inotropic effect of isoprenaline remained unaffected by NMMA or methylene blue.The present study provides evidence that the indirect negative inotropic effect of M-cholinoceptor agonists is not due to an effect of NO in the human myocardium. Furthermore, the well known enhancement of cGMP in response to M-cholinoceptor stimulation appears not to be involved in this antiadrenergic effect.     

Influenza Vaccination and Asthma

Influenza is an important epidemic and pandemic illness associated with serious morbidity and mortality in unprotected communities. Patients at increased risk of infection are those with pre-existing cardiopulmonary disease including asthma. The influenza virus has the ability to produce antigenic changes posing problems for vaccine development. Influenza vaccines have been available for over 50 years. Despite the continuing global threat posed by infection and recommendations in many countries that immunisation should be widely given, uptake rates are variable and often poor. It has been demonstrated that infection with influenza and other respiratory viral pathogens can produce exacerbations of asthma throughout the age groups. Despite this, vaccine uptake rates in asthmatic populations are quite low. Poor uptake rates are attributed to a number of factors and we review the evidence for the widely held view that influenza vaccination produces exacerbations of chronic airflow obstruction including asthma. Observational studies have found conflicting results: some post immunisation changes in bronchial hyperreactivity and increased requirements of bronchodilator therapy have been in some, but not all, studies. Placebo-controlled trials have not demonstrated any clinical deterioration although one study showed a small reduction in peak expiratory flow rate. Intranasal administration of cold-adapted live vaccines and new nucleic acid vaccines are briefly considered. Live adapted vaccines have been shown to be effective in influenza immunoprophylaxis and limited data on their use in patients with asthma suggest that they can be administered safely. In conclusion, based up on current studies and evidence, it seems likely that influenza infection produces morbidity in patients with asthma but that any potential adverse effects of influenza immunisation are outweighed by the benefits in this population. However, placebo-controlled trials are few and only small numbers of asthmatic patients have been investigated.     

Incipient left ventricular rupture complicating anomalous left coronary artery

A 4-month-old girl presented with 2 weeks of symptoms and physical signs of heart failure. Echocardiography demonstrated marked left ventricular dilation, thinning of the myocardium with anterolateral akinesis, mitral regurgitation, a moderate pericardial collection, and an anomalous left coronary artery from the pulmonary artery. At operation there was a tense hemopericardium and a site of imminent rupture through a transmural anterior infarction. The anomalous artery was reimplanted in the ascending aorta, and an extensive infarct resection and ventricular repair performed. Support with a left ventricular assist device was required for 3 days, but the infant subsequently made a satisfactory recovery. Left ventricular rupture is a very rare complication of this lesion, but should be considered if there is evidence of a pericardial collection.