Spectral integration in auditory cortex: mechanisms and modulation

Auditory cortex contributes to the processing and perception of spectrotemporally complex stimuli. However, the mechanisms by which this is accomplished are not well understood. In this review, we examine evidence that single cortical neurons receive input covering much of the audible spectrum. We then propose an anatomical framework by which spectral information converges on single neurons in primary auditory cortex, via a combination of thalamocortical and intracortical "horizontal" pathways. By its nature, the framework confers sensitivity to specific, spectrotemporally complex stimuli. Finally, to address how spectral integration can be regulated, we show how one neuromodulator, acetylcholine, could act within the hypothesized framework to alter integration in single neurons. The results of these studies promote a cellular understanding of information processing in auditory cortex.     

Non-Hodgkin's lymphoma and residential proximity to toxic industrial waste in southern Israel

Environmental exposure has been linked to non-Hodgkin's lymphoma (NHL). Toxic volatile compounds were found in groundwater downstream of an industrial site in southern Israel. The risk of NHL and clinical characteristics of NHL patients were analyzed in relation to their proximity to the site.     

Modulation of systemic hemostatic parameters by enoxaparin during gestation in women with thrombophilia and pregnancy loss

Recurrent pregnancy loss (PL) is associated with maternal thrombophilia and prophylaxis with low molecular weight heparin (LMWH) can improve pregnancy outcome in this setting.The aim of this study was to investigate the modulation of systemic hemostatic parameters by enoxaparin in women with recurrent PL and to evaluate plasmatic parameters that would potentially enable monitoring LMWH prophylaxis effect during pregnancy. Study group included 87 women with thrombophilia and PL treated with enoxaparin 40 mg daily vs. 40 mg twice daily. The control group comprised 40 women with normal pregnancies. Blood samples have been collected throughout the period starting at 5-10 weeks of gestation until 6-10 weeks postpartum. The determined plasmatic markers included: anti-Xa activity, total and free tissue factor pathway inhibitor (TFPI), D-dimer, prothrombin fragment 1+2 (PT1+2), activated protein C resistance (APC-SR) and free protein S. Successful pregnancy outcome was recorded in 70 (80.5%) women treated with enoxaparin, without correlation to enoxaparin dosage. Seventeen women (19.5%) had pregnancy loss at 16+/-7 (6-32) weeks of gestation. Anti-Xa levels at 10-15 weeks of gestation were higher (0.39+/-0.38 u/ml) in the successful pregnancy outcome group compared to the abortion group (0.22+/-0.2 u/ml). Prophylactic anti-Xa activity levels (0.28+/-0.13 u/ml) were documented from 15 weeks of gestation until delivery in the successful pregnancy outcome group. Significant increase in anti-Xa, total TFPI and free TFPI levels (P<0.001) was achieved after beginning of LMWH prophylaxis in successful pregnancy outcome group but not in the abortion group. D-dimer and PT1+2 levels appeared to be significantly increased while APC-SR and free protein S levels gradually decreased during pregnancy, with no difference between study groups. These results suggest that LMWH prophylaxis during pregnancy enables modulation of systemic hemostatic parameters via inhibition of factor Xa and increase in plasmatic total and free TFPI levels.     

Transient decrease of neutrophil chemotaxis following aerobic exercise

PURPOSE: Intense exercise affects the immune system, increasing the susceptibility of athletes to viral and bacterial infections. We have previously shown a significant decrease of fMLP-neutrophil migration 24 h after aerobic exercise. In this study we aimed to look at the differential effect of different chemoattractants on neutrophil migration following aerobic exercise, to determine the recovery time, and to better understand the role of the cell skeleton behind the impaired chemotaxis. METHODS: Sixteen female volunteers aged 22-30 yr were tested before, 24, and 48 h after aerobic exercise (30 min running at 70% (.)VO(2max). The submaximal exercise test was conducted a week after the (.)VO(2max) test.We studied the membrane cell receptor response to fMLP, IL-8, and C5a, which have specific ligand-receptor pathways. Further, we studied the cytoskeletal response by investigating the cell polarization and the F-actin polymerization. RESULTS: Significant decrease of the neutrophil net chemotaxis was detected with fMLP, IL-8 and C5a, 24 h after exercise (50 +/- 5%, P = 0.0001; 48 +/- 12%, P = 0.0015; and 32 +/- 11%, P = 0.011, respectively). Complete recovery was observed within 48 h with all chemoattractants. Normal neutrophil random migration and F-actin polymerization were found. Decreased neutrophil polarization was detected (46 +/- 6% vs 22 +/- 8% of polarized cells, before and after effort, respectively; P = 0.004). Correlation between polarization and chemotactic migration was found (r = 0.945; P = 0.001). CONCLUSIONS: The impaired chemotactic response, observed 24 h after exercise, was similar using different chemoattractants. This finding indicates a possible exercise-induced effect on a common factor at the ligand-receptor level. The abnormal cell polarization indicates skeletal dysfunction that should be further investigated and elucidated. The normal fMLP-stimulated-F-actin polymerization reflects an adequate pathway of signal transduction for the formyl peptide.     

Diurnal fluctuation of leukocyte G6PD activity. A possible explanation for the normal neutrophil bactericidal activity and the low incidence of pyogenic infections in patients with severe G6PD deficiency in Israel

Acute hemolytic anemia associated with red blood cell (RBC) glucose-6-phosphate dehydrogenase (G6PD) deficiency is commonly encountered in the Mediterranean basin. Nevertheless, concomitant clinical evidence of white blood cell G6PD deficiency is extremely rare in Israel. This study sought to assess simultaneously levels of G6PD activity in polymorphonuclear leukocytes (PMN) and in red blood cells (RBC) of patients with G6PD deficiency, including full-term newborn infants. In PMN, the correlation between G6PD activity, hexose monophosphate shunt activity, and superoxide anion release was evaluated. In G6PD-deficient patients, a parallel and significantly decreased G6PD activity was found in neutrophils (range of activity 0-4.5 IU/10(6) PMN) and erythrocytes (range of activity 0-1.8 IU/g Hb), compared with healthy controls (5-23 IU/10(6) PMN and 2.4-6.4 IU/g Hb, respectively). A positive correlation was found in PMN between the levels of G6PD activity, hexose monophosphate (HMP) shunt activity, and superoxide anion release (p < 0.01). Nevertheless, all patients' bactericidal activity of neutrophils remained in the range of healthy controls. Although many episodes of acute hemolytic anemia were recorded, no increased incidence of pyogenic infections was observed in any group of patients investigated. Neutrophil and erythrocyte G6PD levels were re-assessed in some of these patients several times a day. A significant diurnal fluctuation of the enzyme activity was found. It is speculated that the patients produce fluctuating daily quantities of NADPH, sufficient to initiate the neutrophil respiratory burst and to achieve normal bactericidal activity, necessary to prevent the development of microbial infections.     

Survival of frozen-thawed human ovarian fetal follicles in long-term organ culture

Ovarian follicles obtained from second and third-trimester human fetuses survived 4 weeks in organ culture and secreted 17-beta estradiol (E(2)).     

Outcome of IgM- and IgG-seropositive cases of varicella zoster in pregnancy

OBJECTIVE: To study the outcome of IgG- and IgM-seropositive cases of varicella zoster virus (VZV) in pregnancy. STUDY DESIGN: The VZV immune status of 120 pregnant women who had been exposed to VZV and did not recall a history of VZV infection was determined, and 109 were VZV immune. Eleven women were both IgG and IgM seropositive, and the outcomes of their pregnancies were studied. RESULTS: Nine of the 11 VZV IgM-, IgG-seropositive pregnant women were asymptomatic, without fetal damage. CONCLUSION: The majority of the women were asymptomatic, but no statement about the relative risk of being affected by the virus can be made.