Effects of perceptual learning on local stereopsis and neuronal responses of V1 and V2 in prism-reared monkeys

Visual performance improves with practice (perceptual learning). In this study, we sought to determine whether or not adult monkeys reared with early abnormal visual experience improve their stereoacuity by extensive psychophysical training and testing, and if so, whether alterations of neuronal responses in the primary visual cortex (V1) and/or visual area 2 (V2) are involved in such improvement. Strabismus was optically simulated in five macaque monkeys using a prism-rearing procedure between 4 and 14 wk of age. Around 2 yr of age, three of the prism-reared monkeys ("trained" monkeys) were tested for their spatial contrast sensitivity and stereoacuity. Two other prism-reared monkeys received no training or testing ("untrained" monkeys). Microelectrode experiments were conducted around 4 yr of age. All three prism-reared trained monkeys showed improvement in stereoacuity by a factor of 7 or better. However, final stereothresholds were still approximately 10-20 times worse than those in normal monkeys. In V1, disparity sensitivity was drastically reduced in both the trained and untrained prism-reared monkeys and behavioral training had no obvious effect. In V2, the disparity sensitivity in the trained monkeys was better by a factor of approximately 2.0 compared with that in the untrained monkeys. These data suggest that the observed improvement in stereoacuity of the trained prism-reared monkeys may have resulted from better retention of disparity sensitivity in V2 and/or from "learning" by upstream neurons to more efficiently attend to residual local disparity information in V1 and V2.

Puerarin injection for unstable angina pectoris

BACKGROUND

Puerarin is extracted from the Chinese herb puerariae lobata. Many users of Chinese herbal medicine believe that puerarin has positive effects in the treatment of coronary heart disease (CHD). In recent years puerarin injection has been widely used to treat CHD and angina pectoris.

OBJECTIVES

To assess the benefits and harms of puerarin injection for unstable angina.

SEARCH STRATEGY

The following electronic databases were searched: The Cochrane Controlled Trials Register on The Cochrane Library (Issue 3, 2004), MEDLINE (1995 to 2004), EMBASE (1995 to 2004), CBM (1995 to 2004), Chinese Cochrane Centre Controlled Trials Register (to 2004), Current Controlled Trials (www.controlled-trials.com) and The National Research Register. We also hand searched 60 Chinese traditional medicine journals.

SELECTION CRITERIA

Randomised controlled trials undertaken on adults with unstable angina evaluating the following types of interventions: Puerarin injection compared to western drugs or placebo, or puerarin injection used with western drugs compared to western drugs alone.

DATA COLLECTION AND ANALYSIS

Data were extracted and analysed independently by two reviewers. Differences in data extraction and analysis were resolved by consensus, referring back to the original article. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

20 trials involving 1240 people were included. All trials identified were classified as having a high risk of bias because of poor reported methodology. The duration of treatment was 7-20 days and no information supplied suggested longer follow-ups were conducted for any trials. This limited the observation to participants who were not undertaking normal activities of daily living. The primary outcome (death) was not report in any trial. For all the secondary outcome measures, frequency of acute angina attacks, improvements in ECG, doses and incidence of nitroglycerine needed and levels of plasma endothelin, there was no evidence that puerarin had better or worse effects to other conventional treatments. There was strong evidence to suggest that puerarin injection plus western drugs was a better treatment option than western drugs alone.

AUTHORS' CONCLUSIONS

Puerarin injection may be effective in unstable angina when used in addition to conventional treatments. However, these finding should be interpreted with care because of the very low methodological quality of studies and potential publication bias. In the light of the findings, a more rigorously designed, randomised double-blind placebo-controlled trial is needed.

Stable Isotope Records from Mount Logan, Eclipse Ice Cores and Nearby Jellybean Lake. Water Cycle of the North Pacific Over 2000 Years and Over Five Vertical Kilometres: Sudden Shifts and Tropical Connections

Three ice cores recovered on or near Mount Logan, together with a nearby lake record (Jellybean Lake), cover variously 500 to 30 000 years. This suite of records offers a unique view of the lapse rate in stable isotopes from the lower to upper troposphere. The region is climatologically important, being beside the Cordilleran pinning-point of the Rossby Wave system and the Aleutian Low. Comparison of stable isotope series over the last 2000 years and model simulations suggest sudden and persistent shifts between modern (mixed) and zonal flow regimes of water vapour transport to the Pacific Northwest. The last such shift was in A.D. 1840. Model simulations for modern and “pure” zonal flow suggest that these shifts are consistent regime changes between these flow types, with predominantly zonal flow prior to ca. A.D. 1840 and modern thereafter. The 5.4 and 0.8 km asl records show a shift at A.D. 1840 and another at A.D. 800. It is speculated that the A.D. 1840 regime shift coincided with the end of the Little Ice Age and the A.D. 800 shift with the beginning of the European Medieval Warm Period. The shifts are very abrupt, taking only a few years at most.

Julibroside J8-induced HeLa cell apoptosis through caspase pathway

The julibroside J8 was isolated from the Albizia julibrissin and evaluated for antiproliferatived on six cancer cell lines (BGC-823, Bel-7402, HeLa, PC-3MIE8, MDA-MB-435 and LH-60) in vitro. Julibroside J8 at 100 microg mL- 1 (46.08 micromol.L- 1) significantly inhibited growth in the first three cell lines. In addition, in HeLa cells typical apoptotic changes in morphology were observed, and further, nuclear damage was observed by Giemsa staining and DNA fragmentation was exhibited. Effects of julibrosideJ8 on induction of DNA fragmentation, caspase-3 activation and downregulation of ICAD expression were effectively inhibited by a caspase-3 inhibitor, z-DEVD-fmk. In addition, apoptosis induced with julibroside J8 was associated with an increase in expression of the apoptosis inducer Bax, and a significant reduction in expression of the apoptosis suppressor Bcl-2 in mitochondria. These results suggest that julibroside J8 induces HeLa death through caspase pathway.

HIV-1 infection and AIDS: consequences for the central nervous system

Infection with the human immunodeficiency virus-1 (HIV-1) can induce severe and debilitating neurological problems that include behavioral abnormalities, motor dysfunction and frank dementia. After infiltrating peripheral immune competent cells, in particular macrophages, HIV-1 provokes a neuropathological response involving all cell types in the brain. HIV-1 also incites activation of chemokine receptors, inflammatory mediators, extracellular matrix-degrading enzymes and glutamate receptor-mediated excitotoxicity, all of which can trigger numerous downstream signaling pathways and disrupt neuronal and glial function. This review will discuss recently uncovered pathologic neuroimmune and degenerative mechanisms contributing to neuronal damage induced by HIV-1 and potential approaches for development of future therapeutic intervention.

Cortical Effects of Brief Daily Periods of Unrestricted Vision During Early Monocular Form Deprivation

Experiencing daily brief periods of unrestricted vision during early monocular form deprivation prevents or reduces the degree of resulting amblyopia. To gain insight into the neural basis for these “protective” effects, we analyzed the monocular and binocular response properties of individual neurons in the primary visual cortex (V1) of macaque monkeys that received intermittent unrestricted vision. Microelectrode-recording experiments revealed significant decreases in the proportion of units that were dominated by the treated eyes, and the magnitude of this ocular dominance imbalance was correlated with the degree of amblyopia. The sensitivity of V1 neurons to interocular spatial phase disparity was significantly reduced in all treated monkeys compared with normal adults. With unrestricted vision, however, there was a small but significant increase in overall disparity sensitivity. Binocular suppression was prevalent in monkeys with constant form deprivation but significantly reduced by the daily periods of unrestricted vision. If neurons exhibited consistent responses to stimulation of the treated eye, monocular response properties obtained by stimulation of the two eyes were similar. These results suggest that the observed protective effects of brief periods of unrestricted vision are closely associated with the ability of V1 neurons to maintain their functional connections from the deprived eye and that interocular suppression in V1 may play an important role in regulating synaptic plasticity of these monkeys.

Feasibility of Supercritical Fluid Chromatography/Mass Spectrometry of Polypeptides with Up to 40-Mers

Supercritical fluid chromatography (SFC) provides a number of advantages over traditional HPLC such as speed, practical use of longer columns, a normal-phase retention mechanism, and reduced use of organic solvents. Yet, it has been a technique traditionally limited to relatively nonpolar compounds. The nature of SFC mobile and stationary phases did not allow the elution of ionic compounds or of peptides, except, in the latter case, for the most hydrophobic peptides. The characterization of peptides is critically important for drug discovery and development in the pharmaceutical industry, as well as for a variety of other important applications. Here, for the first time to our knowledge, we show that relatively large peptides (at least 40 mers), containing a variety of acidic and basic residues, can be eluted in SFC. We used trifluoroacetic acid as additive in a CO2/methanol mobile phase to suppress deprotonation of peptide carboxylic acid groups and to protonate peptide amino groups. A 2-ethylpyridine bonded silica column, which was specifically developed for SFC, was used for the majority of this work. The relatively simple mobile phase was compatible with mass spectrometric detection.

A double-blind, placebo-controlled study of house dust mite immunotherapy in Chinese asthmatic patients

BACKGROUND

The purpose of this study was to determine if house dust mite immunotherapy with Alutard SQ is effective in improving symptom control and reducing rescue medication use in Chinese patients with mild to moderate allergic asthma.

METHODS

This is a double-blind, placebo-controlled study involving 132 asthmatic subjects aged 6-45 years recruited from three different regions of Mainland China. Subjects were given a 52-week course of immunotherapy with Dermatophagoides pteronyssinus extract (Alutard Der p, ALK-Abelló, Hørsholm, Denmark) or placebo while their dose of inhaled corticosteroids (ICS) was maintained.

RESULTS

129 subjects (64 in active group) completed the study. The symptom scores began to diverge at week 29 with the immunotherapy group showing a significantly lower score until week 48 (P = 0.018). Immunotherapy resulted in a significant decline in symptom (P = 0.002) and medication (P = 0.007) scores during the second half of the treatment period. Both groups showed significant improvement in peak flow rate and bronchial hyperresponsiveness. Serum eosinophil cationic protein (ECP) also decreased in both groups of subjects, but peripheral blood eosinophil count remained unchanged. Skin test response decreased in actively treated subjects only, but Der p-specific immunoglobulin E (IgE) remained unchanged. Immunotherapy resulted in a significantly greater improvement in self-evaluation scores (P < 0.01).

CONCLUSIONS

One year treatment with Alutard SQ house dust mite immunotherapy significantly reduced symptoms and medication use in asthmatic subjects. This was associated with a greater subjective improvement in asthma control.

Dynamic changes in orbitofrontal neuronal activity in rats during opiate administration and withdrawal

The orbitofrontal cortex is involved in the reinforcing effects of drugs of abuse. However, how the dynamic activity in OFC changes during opiate administration and withdrawal period has not been investigated. We first tested the effects of opiates and drug craving with the conditioned place preference paradigm, using manganese-enhanced magnetic resonance imaging and traditional electroencephalograph recording techniques in rats. T1-weighted 2D MRI (4.7 T) was used after unilateral injection of MnCl(2) (200 nL, 80 mM) into the right orbitofrontal cortex. The manganese-enhanced magnetic resonance imaging data suggested that the OFC activity decreased during the opiate administration period but recovered increasingly during the withdrawal period. Also, we found decreases and increases in gamma-band (20-100 Hz) activity during the opiate administration and withdrawal period, respectively. Our results showed that orbitofrontal cortex activity decreased during morphine administration and then went up progressively over several days during withdrawal. The time course of the recovery of orbitofrontal activity from inhibition during the withdrawal period may be related to the experience of drug craving.

An ultra-clean firn core from the Devon Island Ice Cap, Nunavut, Canada, retrieved using a titanium drill specially designed for trace element studies

An electromechanical drill with titanium barrels was used to recover a 63.7 m long firn core from Devon Island Ice Cap, Nunavut, Canada, representing 155 years of precipitation. The core was processed and analysed at the Geological Survey of Canada by following strict clean procedures for measurements of Pb and Cd at concentrations at or below the pg g(-1) level. This paper describes the effectiveness of the titanium drill with respect to contamination during ice core retrieval and evaluates sample-processing procedures in laboratories. The results demonstrate that: (1) ice cores retrieved with this titanium drill are of excellent quality with metal contamination one to four orders of magnitude less than those retrieved with conventional drills; (2) the core cleaning and sampling protocols used were effective, contamination-free, and adequate for analysis of the metals (Pb and Cd) at low pg g(-1) levels; and (3) results from 489 firn core samples analysed in this study are comparable with published data from other sites in the Arctic, Greenland and the Antarctic.

The signaling and apoptotic effects of TNF-related apoptosis-inducing ligand in HIV-1 associated dementia

HIV-1 Associated Dementia (HAD) develops during progressive HIV-1 infection and is characterized by cognitive impairments, behavioral disorders and potential progressive motor abnormality. Abnormal inflammation within the central nervous system (CNS), activation of macrophage/microglia and involvement of proinflammatory cytokines have been suggested as primary factors in the pathogenesis of HAD. Impairment of neuronal function and neuronal cell death are believed to be the end pathophysiological result of HAD. TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF family of cytokines, was suggested to participate in apoptotic cell death during HAD. As a death ligand, TRAIL was originally thought to target only tumor cells. TRAIL is not typically present in CNS; however, emerging data show that TRAIL can be induced by immune stimuli on macrophage and microglia, major disease effector cells during HAD. Upregulated TRAIL may then cause neuronal apoptosis through direct interaction with TRAIL receptors on neurons or through macrophage death-mediated release of neurotoxins. In this review, we summarize the pivotal role of TRAIL in HAD and TRAIL-initiated intracellular death cascades that culminate in neuronal apoptosis as observed in HAD.