Essential role of platelet-activating factor receptor in the pathogenesis of Dengue virus infection

Severe dengue infection in humans causes a disease characterized by thrombocytopenia, increased levels of cytokines, increased vascular permeability, hemorrhage, and shock. Treatment is supportive. Activation of platelet-activating factor (PAF) receptor (PAFR) on endothelial cells and leukocytes induces increase in vascular permeability, hypotension, and production of cytokines. We hypothesized that activation of PAFR could account for the major systemic manifestations of dengue infection. Inoculation of adult mice with an adapted strain of Dengue virus caused a systemic disease, with several features of the infection in humans. In PAFR(-/-) mice, there was decreased thrombocytopenia, hemoconcentration, decreased systemic levels of cytokines, and delay of lethality, when compared with WT infected mice. Treatment with UK-74,505, an orally active PAFR antagonist, prevented the above-mentioned manifestations, as well as hypotension and increased vascular permeability, and decreased lethality, even when started 5 days after virus inoculation. Similar results were obtained with a distinct PAFR antagonist, PCA-4246. Despite decreased disease manifestation, viral loads were similar (PAFR(-/-)) or lower (PAFR antagonist) than in WT mice. Thus, activation of PAFR plays a major role in the pathogenesis of experimental dengue infection, and its blockade prevents more severe disease manifestation after infection with no increase in systemic viral titers, suggesting that there is no interference in the ability of the murine host to deal with the infection. PAFR antagonists are disease-modifying agents in experimental dengue infection.

Day-night pattern of autonomic nervous system modulation in patients with heart failure with and without sleep apnea

Introduction: Among patients with congestive heart failure (CHF) both obstructive and central sleep apnea (SA) are associated with increased sympathetic activity. However, the day-night pattern of cardiac autonomic nervous system modulation in CHF patients with and without sleep apnea is unknown. Material and methods: Twenty-five CHF patients underwent polysomnography with simultaneous beat-to-beat blood pressure (Portapres), respiration and electrocardiogram monitoring. Patients were divided according to the presence (SA, n=17) and absence of SA (NoSA, n=8). Power spectral analyses of heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS) were determined in periods with stable breathing while awake at 6 AM, 10 AM, 10 PM, as well as during stage 2 sleep. In addition, muscle sympathetic nerve activity (MSNA) was evaluated at 10 AM. Results: RR variance, low-frequency (LF), high-frequency (HF) powers of HRV, and BRS were significantly lower in patients with SA compared with NoSA in all periods. HF power, a marker of vagal activity, increased during sleep in patients with NoSA but in contrast did not change across the 24-hour period in patients with SA. MSNA was significantly higher in patients with SA compared with NoSA. RR variance, LF and HF powers correlated inversely with simultaneous MSNA (r=-0.64, -0.61, and -0.61 respectively; P < 0.01). Conclusions: Patients with CHF and SA present a reduced and blunted cardiac autonomic modulation across the 24-hour period. These findings may help to explain the increased cardiovascular risk in patients with CHF and SA. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Role of the spinal cord NO/cGMP pathway in the control of arterial pressure and heart rate

The modulatory effect of nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway on sympathetic preganglionic neurons still deserves further investigation. The present study was designed to examine the role of the spinal cord NO/cGMP pathway in controlling mean arterial pressure and heart rate. We observed that intrathecal administration of the NO synthase inhibitor N omega-Nitro-L-arginine methyl ester hydrochloride (L-NAME) causes an increase in mean arterial pressure but does not affect heart rate. Intrathecal administration of the soluble guanylyl cyclase inhibitor 1H-[1,2,4] Oxadiazolo[4,3-a] quinoxalin-1-one (ODQ) does not change mean arterial pressure and heart rate. The precursor for NO synthesis, L-arginine, reduces both mean arterial pressure and heart rate while administration of ODQ before L-arginine impaired decreases in mean arterial pressure and heart rate. Administration of the N-methyl-D-aspartate (NMDA) receptor antagonist DL-2-amino-5-phosphonopentanoic acid (AP5) after L-NAME does not affect increases in mean arterial pressure promoted by NO synthase inhibition. Although the hypotensive and bradycardic responses induced by intrathecal administration of L-arginine depend on cGMP, our results indicate that NO acts to tonically inhibit SPNs, independent of either cGMP or NMDA receptors.

Are l-glutamate and ATP cotransmitters of the peripheral chemoreflex in the rat nucleus tractus solitarius ?

Peripheral chemoreflex activation in awake rats or in the working heart-brainstem preparation (WHBP) produces sympathoexcitation, bradycardia and an increase in the frequency of phrenic nerve activity. Our focus is the neurotransmission of the sympathoexcitatory component of the chemoreflex within the nucleus of the tractus solitarius (NTS), and recently we verified that the simultaneous antagonism of ionotropic glutamate and purinergic P(2) receptors in the NTS blocked the pressor response and increased thoracic sympathetic activity in awake rats and WHBP, respectively, in response to peripheral chemoreflex activation. These previous data suggested the involvement of ATP and L-glutamate in the NTS in the processing of the sympathoexcitatory component of the chemoreflex by unknown mechanisms. For a better understanding of these mechanisms, here we used a patch-clamp approach in brainstem slices to evaluate the characteristics of the synaptic transmission of NTS neurons sending projections to the ventral medulla, which include the premotor neurons involved in the generation of the sympathetic outflow. The NTS neurons sending projections to the ventral medulla were identified by previous microinjection of the membrane tracer dye, 1,1`-dioctadecyl-3,3,3`,3`-tetramethylindocarbocyanine perchlorate (DiI), in the ventral medulla and the spontaneous (sEPSCs) and tractus solitarius (TS)-evoked excitatory postsynaptic current (TS-eEPSCs) were recorded using patch clamp. With this approach, we made the following observations on NTS neurons projecting to the ventral medulla: (i) the sEPSCs and TS-eEPSCs of DiI-labelled NTS neurons were completely abolished by 6,7-dinitroquinoxaline-2,3(1H,4H)-dione (DNQX), an antagonist of ionotropic non-NMDA glutamatergic receptors, showing that they are mediated by L-glutamate; (ii) application of ATP increased the frequency of appearance of spontaneous glutamatergic currents, reflecting an increased exocytosis of glutamatergic vesicles; and (iii) ATP decreased the peak of TS-evoked glutamatergic currents. We conclude that L-glutamate is the main neurotransmitter of spontaneous and TS-evoked synaptic activities in the NTS neurons projecting to the ventral medulla and that ATP has a dual modulatory role on this excitatory transmission, facilitating the spontaneous glutamatergic transmission and inhibiting the TS-evoked glutamatergic transmission. These data also suggest that ATP is not acting as a cotransmitter with L-glutamate, at least at the level of this subpopulation of NTS neurons studied.

Puzzling challenges in contemporary neuroscience: Insights from complexity and emergence in epileptogenic circuits

The brain is a complex system that, in the normal condition, has emergent properties like those associated with activity-dependent plasticity in learning and memory, and in pathological situations, manifests abnormal long-term phenomena like the epilepsies. Data from our laboratory and from the literature were classified qualitatively as sources of complexity and emergent properties from behavior to electrophysiological, cellular, molecular, and computational levels. We used such models as brainstem-dependent acute audiogenic seizures and forebrain-dependent kindled audiogenic seizures. Additionally we used chemical OF electrical experimental models of temporal lobe epilepsy that induce status epilepticus with behavioral, anatomical, and molecular sequelae such as spontaneous recurrent seizures and long-term plastic changes. Current Computational neuroscience tools will help the interpretation. storage, and sharing of the exponential growth of information derived from those studies. These strategies are considered solutions to deal with the complexity of brain pathologies such as the epilepsies. (C) 2008 Elsevier Inc. All rights reserved.

Nitric oxide modulates the firing rate of the rat supraoptic magnocellular neurons

In vitro, nitric oxide (NO) inhibits the firing rate of magnocellular neurosecretory cells (MNCs) of hypothalamic supraoptic and paraventricular nuclei and this effect has been attributed to GABAergic activation. However, little is known about the direct effects of NO in MNCs. We used the patch-clamp technique to verify the effect Of L-arginine, a precursor for NO synthesis, and N-omega-nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of NOS, on spontaneous electrical activity of MNCs after glutamatergic and GABAergic blockade in Wistar rat brain slices. 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX) (10 mu M) and DL-2-amino-5-phosphonovaleric acid (DL-AP5) (30 mu M) were used to block postsynaptic glutamatergic currents, and picrotoxin (30 mu M) and saclofen (30 mu M) to block ionotropic and metabotropic postsynaptic GABAergic currents. Under these conditions, 500 mu M L-arginine decreased the firing rate from 3.7 +/- 0.6 Hz to 1.3 +/- 0.3 Hz. Conversely, 100 mu M L-NAME increased the firing rate from 3.0 +/- 0.3 Hz to 5.8 +/- 0.4 Hz. All points histogram analysis showed changes in resting potential from -58.1 +/- 0.8 mV to -62.2 +/- 1.1 mV in the presence of L-arginine and from -59.8 +/- 0.7 mV to -56.9 +/- 0.8 mV by L-NAME. Despite the nitrergic modulator effect on firing rate, some MNCs had no significant changes in their resting potential. In those neurons, hyperpolarizing after-potential (HAP) amplitude increased from 12.4 +/- 1.2 mV to 16.8 +/- 0.7 mV by L-arginine, but without significant changes by L-NAME treatment. To our knowledge, this is the first demonstration that NO can inhibit MNCs independent of GABAergic inputs. Further, our results point to HAP as a potential site for nitrergic modulation. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.

Basal levels of DNA damage detected by micronuclei and comet assays in untreated breast cancer patients and healthy women

Breast cancer is the second most frequent type of cancer worldwide and is the most common malignant disease among women. Risk factors for breast cancer include early menarche, late menopause, hormonal therapies, exposure to environmental pollutants, smoking and alcohol use. However, increased or prolonged exposure to estrogen is the most important risk factor. It has been suggested that accumulation of DNA damage may contribute to breast carcinogenesis. Epidemiological studies suggest that cytogenetic biomarkers such as micronuclei in peripheral blood lymphocytes may predict cancer risk because they indicate genomic instability in target tissues. The objective of the present study was to evaluate the frequencies of micronuclei and the extent of DNA damage detected by comet assay in peripheral blood lymphocytes of untreated breast cancer patients and healthy women. The study was conducted using peripheral blood lymphocytes from 45 women diagnosed for Ductal ""in situ"" or invasive breast carcinoma and 85 healthy control women. Micronuclei and comet assays were performed to detect spontaneous DNA damage. The results showed that micronuclei frequencies and tail intensity, detected by comet assay, were significantly higher in the breast cancer group than in controls. The levels of DNA damage were similar in smokers and non-smokers, and aging did not influence the frequencies of micronuclei or tail intensity values observed in either group. In conclusion, the present work demonstrates higher levels of DNA damage in untreated breast cancer patients than in healthy women.

Chronic administration of harmine elicits antidepressant-like effects and increases BDNF levels in rat hippocampus

A growing body of evidence has pointed to the beta-carboline harmine as a potential therapeutic target for the treatment of major depression. The present study was aimed to evaluate behavioural and molecular effects of the chronic treatment with harmine and imipramine in rats. To this aim, rats were treated for 14 days once a day with harmine (5, 10 and 15 mg/kg) and imipramine (10, 20 and 30 mg/kg) and then subjected to the forced swimming and open-field tests. Harmine and imipramine, at all doses tested, reduced immobility time of rats compared with the saline group. Imipramine increased the swimming time at 20 and 30 mg/kg and harmine increased swimming time at all doses. The climbing time increased in rats treated with imipramine (10 and 30 mg/kg) and harmine (5 and 10 mg/kg), without affecting spontaneous locomotor activity. Brain-derived neurotrophic factor (BDNF) hippocampal levels were assessed in imipramine and harmine-treated rats by ELISA sandwich assay. Interestingly, chronic administration of harmine at the higher doses (10 and 15 mg/kg), but not imipramine, increased BDNF protein levels in rat hippocampus. Finally, these findings further support the hypothesis that harmine could bring about behavior and molecular effects, similar to antidepressants drugs.

Brazilian experience with two conditioning regimens in patients with multiple sclerosis: BEAM/horse ATG and CY/rabbit ATG

Studies have shown that autologous hematopoietic SCT (HSCT) can be used as an intensive immunosuppressive therapy to treat refractory patients and to prevent the progression of multiple sclerosis (MS). This is a prospective multicentric Brazilian MS trial comparing two conditioning regimens: BEAM/horse ATG and CY/rabbit ATG. Most (80.4%) of the 41 subjects in the study had the secondary progressive MS subtype and the mean age was 42 years. The baseline EDSS score in 58.5% of the subjects was 6.5 and 78% had a score of 6.0 or higher, respectively. The complication rate during the intra-transplantation period was 56% for all patients: 71.4% of the patients in the BEAM/hATG group and 40% in the CY/rATG group (P = 0.04). Three subjects (7.5%) died of cardiac toxicity, sepsis and alveolar hemorrhage, all of them in the BEAM/ATG group. EFS was 58.54% for a ll patients: 47% in the BEAM/hATG group and 70% in the CY/rATG group (P = 0.288). In conclusion, the CY/rATG regimen seems to be associated with similar outcome results, but presented less toxicity when compared with the BEAM/hATG regimen. Long-term follow-up would be required to fully assess the differences in therapeutic effectiveness between the two regimens. Bone Marrow Transplantation (2010) 45, 239-248; doi:10.1038/bmt.2009.127; published online 6 July 2009

Electrophysiologic Activity of the Vestibular Fold

Objectives: To assess the vestibular fold muscle after cordectomy and laryngeal reconstruction, the pattern of motor unit recruitment during sound emission, and the morphologic characteristics of motor unit action potentials. Design: Prospective analysis. Setting: Tertiary academic hospital. Patients: We evaluated 11 men (mean age, 65.7 years; age range, 53-82 years) who underwent laryngofissure, cordectomy, and laryngeal reconstruction with a vestibular fold flap. Interventions: Laryngeal electromyography with the insertion of a needle electrode for the assessment of the electrophysiologic activity of thyroartenoid muscle fibers and of the cricothyroid muscle on the operated on and nonoperated on sides. The thyroarytenoid muscle was evaluated by introducing a needle electrode through the thyroid cartilage and the cricothyroid membrane. Main Outcome Measures: Activities of needle insertion, spontaneous muscle activity during rest, and pattern of motor unit recruitment. Results: Seven patients (64%) had vestibular fold muscle fiber, all of whom showed motor unit recruitment in response to sound emission. No neurogenic muscle injuries were observed except in 1 patient with evidence of chronic injury. Conclusion: After cordectomy and laryngeal reconstruction, thyroarytenoid muscle fibers are present in the vestibular fold, with motor unit recruitment during sound emission.

Rubella Vaccination of Unknowingly Pregnant Women: The Sao Paulo Experience, 2001

Background. Rubella vaccination is contraindicated during pregnancy. During mass immunization of women of childbearing age against rubella, women unknowingly pregnant may be vaccinated. To evaluate the effects of rubella vaccination during pregnancy, the Brazilian state of Sao Paulo conducted a follow-up study of pregnant women vaccinated during a rubella campaign in 2001. Methods. Women vaccinated during pregnancy were reported to a national surveillance system. In the state of Sao Paulo, follow-up of vaccinated women included household interviews. Serum samples from vaccinated women were tested for antirubella antibodies to classify susceptibility to rubella infection. Children born to susceptible mothers were tested for evidence of congenital rubella infection and evaluated for signs of congenital rubella syndrome. Results. The Sao Paulo State Health Department received 6473 notifications of women vaccinated during pregnancy. Serology performed for 5580 women identified 811 (15%) that were previously susceptible. Incidence of spontaneous abortion or stillbirth among previously susceptible vaccinated women was similar to women with prior immunity. Twenty-seven (4.7%) of 580 newborns tested had evidence of congenital rubella infection; none had congenital rubella syndrome. Conclusions. Mass rubella vaccination of women of childbearing age was not associated with adverse birth outcomes or congenital rubella syndrome among children born to women vaccinated during pregnancy.

Evidence of Renal Infection in Fatal Cases of 2009 Pandemic Influenza A (HI NI)

The 2009 pandemic influenza A (H1N1) caused significant morbidity and mortality. Acute lung injury is the hallmark of the disease, but multiple organ system dysfunction can develop and lead to death. Therefore, we sought to investigate whether there was postmortem evidence of H1N1 presence and virus-induced organ injury in autopsy specimens. Five cases in which patients died of influenza A (H1N1) virus infection were studied. The lungs of all patients showed macroscopic and microscopic findings already described for H1N1 (consolidation, edema, hemorrhage, alveolar damage, hyaline membrane, and inflammation), and H1N1 viruses were present in alveolar cells in immunochemical studies. Acute tubular necrosis was present in all cases, but there was no evidence of direct virus-induced kidney injury. Nevertheless, H1N1 viruses were found in the cytoplasm of glomerular macrophages in the kidneys of 4 patients. Therefore, our data provide strong evidence that H1N1 presence is not restricted to the lungs.

The effect of ovariectomy on cardiac autonomic control in rats submitted to aerobic physical training

We have investigated the ovariectomy effects on the cardiovascular autonomic adaptations induced by aerobic physical training and the role played by nitric oxide (NO). Female Wistar rats (n =70) were divided into five groups: Sedentary Sham (SS): Trained Sham (TS); Trained Hypertensive Sham treated with N(C)-nitro-L-arginine methyl ester (L-NAME) (THS): Trained Ovariectomized (TO); and Trained Hypertensive Ovariectomized treated with L-NAME (THO). Trained groups were submitted to a physical training during 10 weeks. The cardiovascular autonomic control was investigated in all groups using different approaches: 1) pharmacological evaluation of autonomic tonus with methylatropine and propranolol; 2) analysis of heart rate (HR) and systolic arterial pressure (AP) variability; 3) spontaneous baroreflex sensitivity (BRS) evaluation. Hypertension was observed in THS and THO groups. Pharmacological analysis showed that TS group had increased predominance of autonomic vagal tonus compared to SS group. HR and intrinsic HR were found to be reduced in all trained animals. TS group, compared to other groups, showed a reduction in LF oscillations (LF=0.2-0.75 Hz) of pulse interval in both absolute and normalized units as well as an increase in HF oscillations (HF=0.75-2.50 Hz) in normalized unit. FIRS analysis showed that alpha-index was different between all groups. TS group presented the greatest value, followed by the TO, SS. THO and THS groups. Ovariectomy has negative effects on cardiac autonomic modulation in trained rats, which is characterized by an increase in the sympathetic autonomic modulation. These negative effects suggest NO deficiency. In contrast, the ovariectomy seems to have no effect on AP variability. (C) 2008 Elsevier B.V. All rights reserved.

Inflammatory mediators involved in the nociceptive and oedematogenic responses induced by Tityus serrulatus scorpion venom injected into rat paws.

The present study investigated the role of kinins, prostaglandins (PGs) and nitric oxide (NO) in mechanical hypernociception, Spontaneous nociception and paw oedema after intraplantar (ipl) injection of Tityus serrulatus venom (Tsv) in male Wistar rats. Tsv was ipl-injected in doses of 0.01-10 mu g/paw. Pre-treatment (30 min prior) with DALBK (100 nmol/paw) and icatibant (10 nmol/paw), B1 and B2 selective kinin receptor antagonists, L-NAME (50 mg/kg, i.p., a non-selective nitric oxide synthase inhibitor) or celecoxib, selective COX-2 inhibitor, was given 1 h prior per os (5 mg/kg, p.o.), significantly reduced the hypernociceptive response (Von Frey method), the spontaneous nociception (determined by counting the number of flinches) and paw oedema (plethysmometer method) induced by Tsv at doses of 1.0 and 10 mu g/paw for both nociceptive and oedematogenic responses, respectively. Nevertheless, indomethacin (5 mg/kg, i.p.. 30 min prior) was ineffective in altering all of these events. The results of the present study show that Tsv, injected ipl into the rat paw, causes a dose-dependent paw oedema, mechanical hypernociception and flinches (a characteristic biphasic response) in which kinins and NO are substantially involved. Although celecoxib was effective against the oedema and pain caused by Tsv, COX-2 does not seem to be involved in the inflammatory response caused by Tsv. (C) 2008 Elsevier Ltd. All rights reserved.

Perinatal outcome of fetal atrioventricular block - One-hundred-sixteen cases from a single institution

Background-Fetal atrioventricular (AV) block is an uncommon lesion with significant mortality. Because of the rarity of this disorder, the natural course, extensive evaluation of untreated fetuses, and late follow-up remain unclear. Methods and Results-Of the 116 consecutive cases of fetal AV block studied from 1988 to 2006, only 1 was terminated, and 75% were live births. Fifty-nine cases of AV block were associated with major structural heart disease, mainly left atrial isomerism (n = 40), with only 26% of neonatal survivors. Of the 57 fetuses with normal cardiac anatomy, 41 (72%) were positive for maternal antinuclear antibodies, and 32 of these seropositive mothers did not receive any treatment. This untreated group had live-birth and 1-year infant survival rates of 93% and 90%, respectively. Five fetuses from seronegative mothers showed regression to sinus rhythm during pregnancy. The presence of major structural heart disease, hydrops, an atrial rate <= 120 bpm, and a ventricular rate <= 55 bpm were identified as risk factors for mortality. Logistic regression analysis of the whole group showed that the presence of structural heart disease was the only independent predictor of death (P < 0.001). Conclusions-This long-term study confirms that fetal AV block has a poor outcome when associated with structural heart disease and that spontaneous regression of AV block is possible in seronegative forms. The survival rate of >90% of our untreated patients with isolated forms of AV block raises concerns about any decision to intervene with immunosuppressive agents.