Human neuronal threonine-for-leucine-248 alpha 7 mutant nicotinic acetylcholine receptors are highly Ca2+ permeable.

A cDNA coding for the human neuronal nicotinic alpha7 receptor subunit with Leu-248 mutated to threonine was expressed in Xenopus oocytes. When activated by acetylcholine (AcCho), the receptors expressed generated currents that had low desensitization, linear current-voltage relation, and high apparent affinity for both AcCho and nicotine. These characteristics are similar to those already described for the chick threonine-for-leucine-247 alpha7 nicotinic AcCho receptor (nAcChoR) mutant (L247Talpha7).

Group III muscle afferents evoke reflex depressor responses to repetitive muscle contractions in rabbits.

Repetitive-twitch contraction of the hindlimb muscles in anesthetized rabbits consistently evokes a reflex depressor response, whereas this type of contraction in anesthetized cats evokes a reflex pressor response in about one-half of the preparations tested. Rapidly conducting group III fibers appear to comprise the afferent arm of the reflex arc, evoking the depressor response to twitch contraction in rabbits because electrical stimulation of their axons reflexly decreases arterial pressure. In contrast, electrical stimulation of the axons of slowly conducting group III and group IV afferents reflexly increases arterial pressure in rabbits.

High-frequency dielectric study of side-chain dynamics in poly(lysine) aqueous solutions.

The high-frequency dielectric properties of poly(lysine) of different chirality in aqueous solutions have been measured in the frequency range from 1 MHz to 1.8 GHz. The dielectric spectra show the existence of relatively small dielectric dispersions at around 100 MHz that have been attributed to internal motion in the polymer chain, due to side-chain polar groups.

Emotion-related cerebral asymmetry: hemodynamics measured by functional ultrasound.

This study assessed the use of transcranial Doppler ultrasound in detecting selective changes in cerebral blood flow velocity during emotional processes. The role of the respective hemispheres in emotional processing is controversial. Cerebral control of emotional processing has previously been investigated by analysis of patients with unilateral brain damage, experiments with selective stimulation of only one hemisphere, and more recently by imaging techniques measuring local cerebral blood flow.

Interactions of anthracyclines with zwitterionic phospholipid monolayers at the air-water interface.

The present note describes the use of surface pressure measurements (Langmuir monolayer technique) for the analysis of interactions of two different anthracyclines (adriamycin and daunorubicin) with a non-ionic, zwitterionic phospholipid monolayer, at the air-water interface. Because the surface membrane of the cell is the first barrier encountered by the anthracyclines in the treatment of cancer, drug-membrane interactions studied in model (monolayers or bilayers) and natural systems play an important role in the understanding of the bioactivity properties of these molecules. We report here the rate constants of the adsorption process of adriamycin and daunorubicin in the presence of a zwitterionic phospholipid monolayer at the air-water interface.

Homology-dependent gene silencing in plants and fungi: a number of variations on the same theme.

Homology-dependent gene silencing is a phenomenon that occurs in a broad range of organisms and has implications for both basic and applied science. Gene silencing is a mechanism that controls invading transposons and provides protection against virus infections. It also has evolutionary implications in genome maintenance.

The growth-related gene product beta induces sphingomyelin hydrolysis and activation of c-Jun N-terminal kinase in rat cerebellar granule neurones.

The growth-related gene product beta (GRObeta) is a small chemoattractant cytokine that belongs to the CXC chemokine family, and GRObeta receptors are expressed in the brain, including the cerebellum. We demonstrate that rat cerebellar granule neurones express the GRObeta receptor CXCR2. We also show that, in addition to the known stimulation of a phosphoinositide-specific phospholipase C, GRObeta activates both neutral (N-) and acidic (A-) sphingomyelinases (SMase) and the stress-activated c-Jun N-terminal kinase 1 (JNK1).

Glutathione depletion causes cytochrome c release even in the absence of cell commitment to apoptosis.

We demonstrate here that the release of mature cytochrome c from mitochondria is a cellular response to the depletion of glutathione, the main intracellular antioxidant, independently from the destiny of the cells, i.e., apoptosis or survival.

Role of a white collar-1-white collar-2 complex in blue-light signal transduction.

Mutations in either white collar-1 (wc-1) or white collar-2 (wc-2) lead to a loss of most blue-light-induced phenomena in Neurospora crassa. Sequence analysis and in vitro experiments show that WC-1 and WC-2 are transcription factors regulating the expression of light-induced genes. The WC proteins form homo- and heterodimers in vitro; this interaction could represent a fundamental step in the control of their activity.

The archaea monophyly issue: A phylogeny of translational elongation factor G(2) sequences inferred from an optimized selection of alignment positions.

A global alignment of EF-G(2) sequences was corrected by reference to protein structure. The selection of characters eligible for construction of phylogenetic trees was optimized by searching for regions arising from the artifactual matching of sequence segments unique to different phylogenetic domains. The spurious matchings were identified by comparing all sections of the global alignment with a comprehensive inventory of significant binary alignments obtained by BLAST probing of the DNA and protein databases with representative EF-G(2) sequences.

Effects of nicergoline on the retinal and cortical electrophysiological responses in glaucoma patients: a preliminary open study.

Purpose: The retinal dysfunction and the delayed visual cortex responses shown by patients affected by glaucoma can be objectively assessed by Pattern Electroretinogram (PERG) and Visual Evoked Potentials (VEP) recordings. The present study aims to evaluate the effects of nicergoline on the retinal function and on the visual cortical responses in glaucoma patients.

Methods: Sixty patients (mean age 44.

A model for the incorporation of metal from the copper chaperone CCS into Cu,Zn superoxide dismutase.

Background: Recent studies have identified the human copper chaperone CCS as the presumed factor responsible for copper incorporation into superoxide dismutase (SOD). A lack of knowledge of the chaperone's three-dimensional structure has prevented understanding of how the copper might be transferred.

Results: The three-dimensional structure of CCS was homology modelled using the periplasmic protein from the bacterial mercury-detoxification system and the structure of one subunit of the human SOD dimeric enzyme as templates.

Visual function correlates with nerve fiber layer thickness in eyes affected by ocular hypertension.

Purpose: To test whether the high variability observed when measuring pattern electroretinogram (PERG), visual evoked potentials (VEP), and spatial contrast sensitivity (SCS) in eyes with ocular hypertension is associated with variation in nerve fiber layer thickness, as measured by optical coherence tomography (OCT).

Methods: The study involved 32 untreated eyes (32 patients; age range, 29-64 years) showing a normal whiteon-white 24/2 Humphrey (San Leandro, CA) perimetry, IOP between 23 and 28 mm Hg, best corrected acuity of 20/20 or better, and none of the following papillary signs on conventional color stereo slides: rim notch(es), peripapillary splinter hemorrhages, or increased vertical-to-horizontal cup-to-disc ratio. On recruitment, each eye underwent SCS testing, OCT, PERG, and VEP recordings.

The role of anillin in meiotic cytokinesis of Drosophila males.

Anillin is a 190 kDa actin-binding protein that concentrates in the leading edges of furrow canals during Drosophila cellularization and in the cleavage furrow of both somatic and meiotic cells. We analyzed anillin behavior during D. melanogaster spermatogenesis, and focused on the relationships between this protein and the F-actin enriched structures.

Nicotinic acetylcholine receptors assembled from the alpha7 and beta3 subunits.

Intracellular recordings were performed in voltage-clamped Xenopus oocytes upon injection with a mixture of cDNAs encoding the beta3 and mutant alpha7 (L247Talpha7) neuronal nicotinic acetylcholine receptor (nAChR) subunits. The expressed receptors maintained sensitivity to methyllycaconitine and to alpha-bungarotoxin but exhibited a functional profile strikingly different from that of the homomeric L247Talpha7 receptor. The heteromeric L247Talpha7beta3 nAChR had a lower apparent affinity and a faster rate of desensitization than L247Talpha7 nAChR, exhibited nonlinearity in the I-V relationship, and was inhibited by 5-hydroxytryptamine, much like wild type alpha7 (WTalpha7) nAChR.

Cytidine-5'-diphosphocholine (citicoline) improves retinal and cortical responses in patients with glaucoma.

Purpose: To evaluate the effects of cytidine-5'-diphosphocholine (citicoline) on retinal function and on cortical responses in patients with glaucoma.

Design: Randomized clinical trial.

Participants: Forty patients with open-angle glaucoma were randomly divided into two age-matched groups: citicoline group ([GC] n = 25) and placebo group ([GP] n = 15).

Gene silencing in Neurospora crassa requires a protein homologous to RNA-dependent RNA polymerase.

In plants and fungi, the introduction of transgenes can lead to post-transcriptional gene silencing. This phenomenon, in which expression of the transgene and of endogenous genes containing sequences homologous to the transgene can be blocked, is involved in virus resistance and genome maintenance. Transgene-induced gene silencing has been termed quelling in Neurospora crassa and co-suppression in plants.

Ultrasonographic and Biochemical Markers of Preterm Labor.

> At present preterm delivery is the leading cause of perinatal morbidity and mortality and its incidence is remained stable during the past 10 years. Conventional methods of identifying patients at risk of preterm delivery such as obstetrics history, demographic factors or evaluation of uterine contractions and cervix by digital examination show disappointintly low sensitivity and positive predictive value. In this review we describe new ultrasonographic and biochemical approaches that have been recently proposed to screen for preterm labor both in patients with intact and with premature rupture of the membranes.

Optimal rejection of movement artefacts from myoelectric signals by means of a wavelet filtering procedure.

In this work the problem of rejection of motion artefacts from surface myoelectric signals, recorded during dynamic contractions, is studied. In fact, the extraction of frequency parameters and the detection of muscular activation patterns can be detrimentally affected by artefacts due to the movement of the surface electrodes, particularly stressed by the dynamic conditions of the exercise performed during measurement. In order to overcome this difficulty, four different filtering procedures have been tested and compared: a high-pass filtering procedure, a moving average procedure, a moving median procedure and a new adaptive wavelet based procedure, expressly designed for this work.

Childhood Leber's hereditary optic neuropathy (ND1/3460) with visual recovery.

The authors report the clinical features and the results of genetic and biochemical studies of a child affected by ND1/3460 Leber's hereditary optic neuropathy, who demonstrates a persistent visual recovery after protracted monitoring. A 10-year-old male suffered from a severe right visual impairment that was incidentally detected. Within 2 months the left eye was also seriously involved, and visual acuity worsened to 20/300 in both eyes, associated with bilateral cecocentral scotomas and dyschromatopsia.

The root of the universal tree of life inferred from anciently duplicated genes encoding components of the protein-targeting machinery.

The key protein of the signal recognition particle (termed SRP54 for Eucarya and Ffh for Bacteria) and the protein (termed SRalpha for Eucarya and Ftsy for bacteria) involved in the recognition and binding of the ribosome SRP nascent polypeptide complex are the products of an ancient gene duplication that appears to predate the divergence of all extant taxa. The paralogy of the genes encoding the two proteins (both of which are GTP triphosphatases) is argued by obvious sequence similarities between the N-terminal half of SRP54(Ffh) and the C-terminal half of SRalpha(Ftsy). This enables a universal phylogeny based on either protein to be rooted using the second protein as an outgroup.

Neural conduction in visual pathways in newly-diagnosed IDDM patients.

Objectives: Visual evoked potentials (VEPs) show abnormal responses in newly-diagnosed insulin-dependent diabetic (IDDM) patients. Electrophysiological methods allow one to dissect and explore different structures contributing to neural conduction in the visual pathways. The aim of our work was to assess whether the VEP abnormalities are due to impaired function of the retinal layers and/or a delayed conduction in the postretinal visual pathways.

Ultrasonographic assessment of the uterine cervix and interleukin-8 concentrations in cervical secretions predict intrauterine infection in patients with preterm labor and intact membranes.

Objective: Interleukin-8 concentrations in cervical secretions have been related to microbial invasion of the amniotic cavity and histological chorioamnionitis. Since a short uterine cervix may be a risk factor for intrauterine infection, we set out to determine the interrelationship between cervical-secretion interleukin-8 concentration, cervical length measured by transvaginal sonography and intrauterine infection in women with preterm labor and intact membranes.

Design: The study group comprised 144 pregnant women admitted to hospital for preterm labor and intact membranes.