Restoration of visual orienting into a cortically blind hemifield by reversible deactivation of posterior parietal cortex or the superior colliculus

A contralateral hemineglect of the visual field can be induced by unilateral cooling deactivation of posterior middle suprasylvian (pMS) sulcal cortex of the posterior parietal region, and this neglect can be reversed by additional cooling deactivation of pMS cortex in the opposite hemisphere. The purpose of the present study was to test whether an enduring hemianopia induced by removal of all contiguous visual cortical areas of one hemisphere could be reversed by local cooling of pMS cortex in the opposite hemisphere. Two cats sustained large unilateral ablations of the contiguous visual areas, and cooling loops were placed in the pMS sulcus, and in contact with adjacent area 7 or posterior ectosylvian (PE) cortex of the opposite hemisphere. In both instances cooling of pMS cortex, but neither area 7 nor PE, restored a virtually normal level of orienting performance to stimuli presented anywhere in the previously hemianopic field. The reversal was highly sensitive to the extent of cooling deactivation. In a third cat, cooling deactivation of the superficial layers of the contralateral superior colliculus also restored orienting performance to a cortical ablation-induced hemianopia. This reversal was graded from center-to-periphery in a temperature-dependent manner. Neither the cortical ablation nor any of the cooling deactivations had any impact on an auditory detection and orienting task. The deactivations were localized and confirmed by reduced uptake of radiolabeled 2-deoxyglucose to be limited to the immediate vicinity of each cooling loop. The results are discussed in terms of excitation and disinhibition of visual circuits.     

Staphylococcus aureus isolates carrying Panton-Valentine leucocidin genes in England and Wales: frequency, characterization, and association with clinical disease

Staphylococcus aureus isolates carrying the genes that encode for Panton-Valentine leucocidin (PVL), a highly potent toxin, have been responsible for recent outbreaks of severe invasive disease in previously healthy children and adults in the United States of America and Europe. To determine the frequency of PVL-positive isolates sent to the Staphylococcus Reference Unit (United Kingdom) for epidemiological purposes, we tested 515 isolates of S. aureus, and 8 (1.6%) were positive for the PVL locus. A further 470 isolates were selected to explore the association of PVL-positive S. aureus with clinical disease. Of these, 23 (4.9%) were PVL positive and most were associated with skin and soft tissue infections (especially abscesses). The PVL genes were also detected in isolates responsible for community-acquired pneumonia, burn infections, bacteremia, and scalded skin syndrome. Genotyping by pulsed-field gel electrophoresis and multilocus sequence typing revealed that the PVL-positive isolates were from diverse genetic backgrounds, although one prevalent clone of 12 geographically dispersed methicillin-resistant S. aureus (MRSA) isolates was identified (ST80). All 12 isolates were stapylococcal cassette chromosome mec type IVc, had an agr3 allele, and shared a common toxin gene profile (sea-see, seg-sej, eta, etb, and tst negative but etd positive). ST80 strains with similar genetic characteristics have been responsible for community-acquired infections in France and Switzerland. The remaining PVL-positive isolates were mostly methicillin-sensitive S. aureus and belonged to 12 different sequence types, including ST22 and ST30, which are closely related to the most prevalent MRSA clones in United Kingdom hospitals, EMRSA-15 and EMRSA-16, respectively.     

Associations between Self-Reported Daily Affect Ratings and Sleep Duration during the First Two Weeks of Antidepressant Therapy

ABSTRACT

Background: In the context of a randomized controlled trial evaluating the efficacy of augmenting fluoxetine treatment in young adults with major depressive disorder (MDD) using a modified repeated partial sleep deprivation protocol contrasting 2 weeks of restricted time in bed (i.e., 6 h TIB) to no time in bed restriction (i.e., 8 h TIB) the study examines whether sleep duration and the timing of repeated partial sleep deprivation predicts patient-reported affect ratings.

Participants: Participants included 58 young adults with DSM-IV-diagnosed MDD.

Methods: Daily ratings of affect and sleep were collected during the first 2 weeks of initiating fluoxetine treatment, yielding 630 person-days. Actigraphy monitoring was employed to assess compliance with time in bed condition.

Results: Negative affect ratings and positivity ratios in the morning were more improved among participants assigned to the 6 h TIB condition compared to the 8 h TIB group. Participants whose bedtime was delayed by 2-h nightly demonstrated the most significant improvement in negative affect and positivity ratio during the first 2 weeks of fluoxetine therapy. Moreover, the trajectory of morning negative affect ratings in the first 2 weeks was predictive of remission after 4 weeks of fluoxetine therapy.

Conclusions: These findings suggest that monitoring changes in daily affect may be a valuable marker of early treatment response in young adults with MDD.     

Ultrafine Electrospun Polyamide‐6 Fibers: Effect of Solution Conditions on Morphology and Average Fiber Diameter

Summary: In the present contribution, the electrostatic spinning or electrospinning technique was used to produce ultra‐fine polyamide‐6 (PA‐6) fibers. The effects of solution conditions on the morphological appearance and the average diameter of as‐spun fibers were investigated by optical scanning (OS) and scanning electron microscopy (SEM) techniques. It was shown that the solution properties (i.e. viscosity, surface tension and conductivity) were important factors characterizing the morphology of the fibers obtained. Among these three properties, solution viscosity was found to have the greatest effect. Solutions with high enough viscosities (viz. solutions at high concentrations) were necessary to produce fibers without beads. At a given concentration, fibers obtained from PA‐6 of higher molecular weights appeared to be larger in diameter, but it was observed that the average diameters of the fibers from PA‐6 of different molecular weights had a common relationship with the solution viscosities which could be approximated by an exponential growth equation. Raising the temperature of the solution during spinning resulted in the reduction of the fiber diameters with higher deposition rate, while mixing m‐cresol with formic acid to serve as a mixed solvent for PA‐6 caused the solutions to have higher viscosities which resulted in larger fiber diameters. Lastly, the addition of some inorganic salts resulted in an increase in the solution conductivity, which caused the fiber diameters to increase due to the large increase in the mass flow.

Average diameter of as‐spun fibers plotted as a function of the viscosity of the solutions.     

Effects of dexamethasone and transient malnutrition on rabbits infected with aerosolized Mycobacterium tuberculosis CDC1551

Malnutrition is common in the developing world, where tuberculosis is often endemic. Rabbits infected with aerosolized Mycobacterium tuberculosis that subsequently became inadvertently and transiently malnourished had compromised cell-mediated immunity comparable to that of the rabbits immunosuppressed with dexamethasone. They had significant leukopenia and reduced delayed-type hypersensitivity responses. Malnutrition dampened cell-mediated immunity and would interfere with diagnostic tests that rely on intact CD4 T-cell responses.     

Composite germ cell tumor and B-cell non-Hodgkin's lymphoma arising in the sella turcica

We report the case of a composite malignant neoplasm consisting of germ cell tumor and B-cell non-Hodgkin's lymphoma occurring in the sella turcica of a young girl who presented with hypopituitarism. Routine hematoxylin and eosin-stained sections of a resected suprasellar tumor demonstrated a neoplasm composed of 2 distinct morphologies. A panel of immunohistochemical markers was used to confirm the morphologic impression of germinoma (cytokeratin AE1/AE3-CAM 5.2, cytokeratin 7, neuron-specific enolase, and focally placental alkaline phosphatase positive) and mature B-cell lymphoma (CD20 positive; pancytokeratin, placental alkaline phosphatase, and terminal deoxynucleotidyl transferase negative). To the best of our knowledge, this is the first reported case of such a composite tumor in the central nervous system.     

Role of T cell costimulation in anti-viral immunity

Members of both the CD28 and TNFR families can have costimulatory roles in T cell activation. Gene targeted mice as well as in vivo blocking experiments have established distinct roles for CD28/B7; ICOS/ICOSL; CD27/CD70; 4-1BB/4-1BBL and OX40/OX40L during viral infection. Many issues remain to be addressed, including the timing and location of the interactions, the possibility of partial redundancy between related family members and the molecular basis for the specific phenotypes observed in the different gene targeted mice.     

Cytokines and lipopolysaccharide induce nitric oxide synthase in cultured rat pulmonary artery smooth muscle.

In the current study, we describe cytokine and Escherichia coli lipopolysaccharide (LPS) induction of nitric oxide (NO) synthase mRNA levels in cultured smooth muscle from rat pulmonary artery (RPASM). Exposure of RPASM to interleukin-1 beta, interferon-gamma, or LPS alone did not significantly affect NO synthesis, as determined by nitrite concentrations in media. Exposure to tumor necrosis factor-alpha caused a modest (2x) increase in nitrite production. In contrast, exposure to a combination of the above three cytokines and LPS caused a large increase in NO synthesis. Exposure of RPASM to this combination caused an increase in mRNA levels of NO synthase (as described by Northern blot analysis with 32P-cDNA probe to an inducible form of NO synthase present in murine macrophages) that was apparent as early as 4 h. Expression of the induced gene product after exposure to the cytokine and LPS mixture was evident by significant increases in nitrite production at 12 h. Production of nitrite was completely abolished in the presence of NG-monomethyl-L-arginine (NMA), and this inhibition was reversible by the addition of excess L-arginine. NO synthase mRNA levels were not affected by NMA. The nitrite production induced by the combination of cytokines and LPS was abolished by pretreating cells with cycloheximide. These data indicate that a combination of cytokines and LPS affect expression of the gene for the inducible form of NO synthase in cultured RPASM.     

Diversity of aminoglycoside resistance inEnterobacter cloacae in Greece

NinetyEnterobacter cloacae strains isolated from 12 Greek hospitals were examined in terms of epidemiological types and resistance mechanisms. Using O serotyping 69 % of the strains were assigned to a specific serotype and overall 16 different serotypes were identified. The combination of serotyping, phagetyping and biotyping efficiently discriminated most of the strains, indicating that single epidemic strains were not prevalent, although serotypes 3, 7, and group II predominated. Eight representative strains, all resistant to gentamicin, tobramycin, amikacin and netilmicin, were further examined for transferability and mechanisms of resistance. Aminoglycoside resistance was found to be transferable in most strains, and 13 R plasmids of 40–120 MDa molecular weight were detected. The enzymes detected consisted of three enzymes active against gentamicin [ANT(2), AAC(3)-I and AAC(3)-V]; three active against tobramycin [ANT(2), AAC(3)-V and AAC(6)-I]; two active against netilmicin [AAC(3)-V and AAC(6)-I]; and one active against amikacin [AAC(6)-I]. APH(3) and ANT (3), which modify neomycin and streptomycin plus spectinomycin respectively, were also found. Overall up to five aminoglycoside modifying enzymes were detected on the same R plasmid, AAC(6)-I plus ANT(2) being the most prevalent. The high incidence of multiresistance inEnterobacter cloacae and the fact that resistance is due to enzymatic inactivation of the antibiotics, indicate that in Greece this species might act as a gene pool for the spread of resistance to other bacteria of clinical relevance.     

Clinical evaluation of three rapid methods for the detection of significant bacteriuria.

Random urine specimens (848) were screened for significant bacteriuria by using the 30-min Lumac (3M, St. Paul, Minn.), the 2-min Bac-T-Screen (Marion Laboratories, Inc., Kansas City, Mo.), and the 13-h AutoMicrobic system (AMS) urine identification card (Vitek Systems, Inc., Hazelwood, Mo.). MacConkey and 5% sheep blood agar plates were inoculated with a 10(-4) dilution of urine and used for the reference method. Bac-T-Screen results were uninterpretable for 9.1% of the specimens owing to either urine sample pigmentation (5.3%) or clogging of the filter (3.8%). Screen-negative urine specimens made up 49.6, 57.2, and 48.5% of the total number of specimens evaluated with AMS, Lumac, and Bac-T-Screen, respectively. False-positive results with Lumac and Bac-T-Screen were 20.6 and 22.3%, respectively. False-negative results for cultures with greater than or equal to 10(4) CFU/ml were 22.0% with AMS, 29.4% with Lumac, and 25.5% with Bac-T-Screen, and false-negative results for cultures with greater than or equal to 10(5) CFU/ml were 29.6% with AMS, 9.9% with Lumac, and 7.0% with Bac-T-Screen. For each system, greater than 70% of false-negatives at greater than or equal to 10(5) CFU/ml consisted of mixed or pure cultures of common contaminants. With any of these screening methods, a clinically significant isolate at greater than or equal to 10(5) CFU/ml would rarely be missed (less than or equal to 1.7% for all systems). A cost-effective and rapid approach to urine microbiology could consist of screening out negative specimens by either Lumac or Bac-T-Screen and processing only screen-positive specimens by the AMS.