Atmosphere-Land Bridge between the Pacific and Tropical North Atlantic SST's through the Amazon River basin during the 2005 and 2010 droughts.

The present work uses a new approach to causal inference between complex systems called the Recurrence Measure of Conditional Dependence (RMCD) based on the recurrence plots theory, in order to study the role of the Amazon River basin (AM) as a land-atmosphere bridge between the Niño 3.0 region in the Pacific Ocean and the Tropical North Atlantic. Two anomalous droughts in the Amazon River basin were selected, one mainly attributed to the warming of the Tropical North Atlantic (2005) and the other to a warm phase of El Niño-Southern Oscillation (2010). The results of the RMCD analysis evidence the distinctive behavior in the causal information transferred between the two oceanic regions during the two extreme droughts, suggesting that the land-atmosphere bridge operating over the AM is an active hydroclimate mechanism at interannual timescales, and that the RMCD analysis may be an ancillary resort to complement early warning systems.

Diphenylhexatriene membrane probes DPH and TMA-DPH: A comparative molecular dynamics simulation study.

Fluorescence spectroscopy and microscopy have been utilized as tools in membrane biophysics for decades now. Because phospholipids are non-fluorescent, the use of extrinsic membrane probes in this context is commonplace. Among the latter, 1,6-diphenylhexatriene (DPH) and its trimethylammonium derivative (TMA-DPH) have been extensively used. It is widely believed that, owing to its additional charged group, TMA-DPH is anchored at the lipid/water interface and reports on a bilayer region that is distinct from that of the hydrophobic DPH. In this study, we employ atomistic MD simulations to characterize the behavior of DPH and TMA-DPH in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and POPC/cholesterol (4:1) bilayers. We show that although the dynamics of TMA-DPH in these membranes is noticeably more hindered than that of DPH, the location of the average fluorophore of TMA-DPH is only ~3-4Å more shallow than that of DPH. The hindrance observed in the translational and rotational motions of TMA-DPH compared to DPH is mainly not due to significant differences in depth, but to the favorable electrostatic interactions of the former with electronegative lipid atoms instead. By revealing detailed insights on the behavior of these two probes, our results are useful both in the interpretation of past work and in the planning of future experiments using them as membrane reporters.

Sensing hydration and behavior of pyrene in POPC and POPC/cholesterol bilayers: a molecular dynamics study.

Molecular dynamics (MD) simulations of bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) with varying amounts of cholesterol (0, 5, 20, and 40mol%) were carried out in the absence and presence of inserted pyrene molecules. Both fluorophore and bilayer parameters were computed, for characterization of probe location and dynamics, as well as its effects on the host bilayer. In agreement with previous studies in fluid disordered bilayers, pyrene prefers to be located in the hydrophobic acyl chain region of POPC bilayers, close to the glycerol group of lipid molecules and causes ordering of the lipid acyl chains. However, incorporation of pyrene in binary POPC/cholesterol bilayers decreases the acyl chain order parameter (especially near the end of the chains), opposing the ordering effect of cholesterol. These effects are modest and mainly felt locally. Significantly, as the bilayer is enriched with cholesterol, the relative position of pyrene and the POPC carbonyl and phosphocholine groups is invariant, and the local water density around the probe decreases. This work clarifies and supports the cautious use of pyrene Ham effect to effectively measure equivalent polarity in lipid bilayers. Within the time scale of the MD simulations, which is of the magnitude of the fluorescence lifetime of pyrene, the thermally averaged polarity of lipid bilayers is nearly out of influence of spurious uncertainty in the transverse location of pyrene in the bilayers. This renders the values of equivalent polarity measurements through the pyrene Ham effect more reliable and reproducible than previously expected.

Effect of amphipathic HIV fusion inhibitor peptides on POPC and POPC/cholesterol membrane properties: a molecular simulation study.

T-20 and T-1249 fusion inhibitor peptides were shown to interact with 1-palmitoyl-2-oleyl-phosphatidylcholine (POPC) (liquid disordered, ld) and POPC/cholesterol (1:1) (POPC/Chol) (liquid ordered, lo) bilayers, and they do so to different extents. Although they both possess a tryptophan-rich domain (TRD), T-20 lacks a pocket binding domain (PBD), which is present in T-1249. It has been postulated that the PBD domain enhances FI interaction with HIV gp41 protein and with model membranes. Interaction of these fusion inhibitor peptides with both the cell membrane and the viral envelope membrane is important for function, i.e., inhibition of the fusion process. We address this problem with a molecular dynamics approach focusing on lipid properties, trying to ascertain the consequences and the differences in the interaction of T-20 and T-1249 with ld and lo model membranes. T-20 and T-1249 interactions with model membranes are shown to have measurable and different effects on bilayer structural and dynamical parameters. T-1249's adsorption to the membrane surface has generally a stronger influence in the measured parameters. The presence of both binding domains in T-1249 appears to be paramount to its stronger interaction, and is shown to have a definite importance in membrane properties upon peptide adsorption.

Copy Number Gain at Xq28 in a Child with Global Developmental Delay Associated with a Variant Form of Hoyeraal-Hreidarsson Syndrome.

We report the case of a child from Central Brazil with global developmental delay (GDD), syndromic features, and absence of abnormal skin pigmentation, nail dystrophy, and leukoplakia of the oral mucosa, with a rearrangement at Xq28 harboring the DKC1 gene. GTC-banding revealed a male karyotype (46,XY) with no visible numerical or structural alterations. Chromosomal microarray analysis (CMA) showed a 0.36-Mb gain at Xq28 of maternal origin, encompassing 22 genes, including DKC1. Rearrangements and mutations involving this gene have been associated with dyskeratosis congenita, X-linked (OMIM 305000) and Hoyeraal-Hreidarsson syndrome. CMA was a powerful and efficient approach to identify a gain at Xq28 harboring the DKC1 gene in our patient with GDD syndromic features and no cutaneous alterations, suggesting that this variant is associated with the Hoyeraal-Hreidarsson syndrome.

Constructing regional climate networks in the Amazonia during recent drought events.

Climate networks are powerful approaches to disclose tele-connections in climate systems and to predict severe climate events. Here we construct regional climate networks from precipitation data in the Amazonian region and focus on network properties under the recent drought events in 2005 and 2010. Both the networks of the entire Amazon region and the extreme networks resulted from locations severely affected by drought events suggest that network characteristics show slight difference between the two drought events. Based on network degrees of extreme drought events and that without drought conditions, we identify regions of interest that are correlated to longer expected drought period length. Moreover, we show that the spatial correlation length to the regions of interest decayed much faster in 2010 than in 2005, which is because of the dual roles played by both the Pacific and Atlantic oceans. The results suggest that hub nodes in the regional climate network of Amazonia have fewer long-range connections when more severe drought conditions appeared in 2010 than that in 2005.

Recurrence measure of conditional dependence and applications.

Identifying causal relations from observational data sets has posed great challenges in data-driven causality inference studies. One of the successful approaches to detect direct coupling in the information theory framework is transfer entropy. However, the core of entropy-based tools lies on the probability estimation of the underlying variables. Here we propose a data-driven approach for causality inference that incorporates recurrence plot features into the framework of information theory. We define it as the recurrence measure of conditional dependence (RMCD), and we present some applications. The RMCD quantifies the causal dependence between two processes based on joint recurrence patterns between the past of the possible driver and present of the potentially driven, excepting the contribution of the contemporaneous past of the driven variable. Finally, it can unveil the time scale of the influence of the sea-surface temperature of the Pacific Ocean on the precipitation in the Amazonia during recent major droughts.

Effects of maternal lead administration on monoaminergic, GABAergic and glutamatergic systems.

The effects of perinatal exposure to lead (300 mg/l) on the development of monoaminergic and aminoacidergic systems were evaluated in the striatum, cerebral cortex (Cx), dorsal hippocampus (d-Hipp) and basal-medial hypothalamus. Maternal exposure to lead produced regional alterations in monoamine content, with increases in dopamine and serotonin or their metabolites. Further, decreased glutamate levels were seen in all brain regions studied, while GABA content decreased only in the Cx. Together, these results show that lead causes alterations to neurotransmitter systems during development. These may be related to lead-induced neurobehavioral impairment.

Maternal exposure to delta 9-tetrahydrocannabinol (delta 9-THC) alters indolamine levels and turnover in adult male and female rat brain regions.

Perinatal exposure to delta 9-THC has been shown to produce effects on brain development. In this study we evaluated the changes induced by maternal exposure to delta 9-THC (5 mg/kg per day) from gestational day 5 to postnatal day 24 in eight discrete brain areas on the central serotoninergic system in both adult male and female rats. These result show that maternal exposure to delta 9-THC from gestational day 5 to postnatal day 24 affects development of the various central indoleaminergic system of the offsprings brain. Perinatal exposure to delta 9-THC decreased the levels of 5-HT in hypothalamus and rostral neostriatum in exposed males, and also decreased the levels of 5-HT in ventral hippocampus, septum, and midbrain raphe nuclei in both exposed males and females. Perinatal exposure to delta 9-THC increased the levels of 5-HIAA in dorsal hippocampus, hypothalamus, septum, midbrain raphe nuclei, and rostral neostriatum in exposed males and females. We have also found differences between nonexposed males and females in several brain regions. Our results confirm a regional and sexual specificity in endogenous levels of indoleamine after perinatal delta 9-THC treatment, being the midbrain raphe nuclei the most affected area.

Study of the neurochemical alterations produced in discrete brain areas by perinatal low-level lead exposure.

Although the neurotoxic effects of Pb are well documented, the subcellular mechanisms of this action in the central nervous system are not fully understood. The present work examines some neurochemical parameters in discrete brain areas of pups whose mothers were intoxicated via drinking water with lead (300 mg/L), from day 1 of pregnancy until postnatal day 12. Lead intoxication produced a significant reduction in the activity of the enzymes alkaline phosphatase and ATP-ase in the brain. Furthermore, the levels of adenine nucleotides were significantly altered by treatment, the striatum being the area more affected, whereas lead did not vary the levels of ATP, ADP and AMP in the hypothalamus. On the other hand, there was a general decrease in neurotransmitter levels in all areas, specially in the hippocampus. These data suggest that gestational and lactational exposure to low dose of lead could produce neurochemical changes in discrete brain areas which can be responsible for the neurophysiological and behavioral changes described in lead-intoxicated animals.

Influence of amygdala catecholamines on ovarian and adrenal medullary secretion.

The amygdaloid complex participates in the modulation of endocrine functions, and contains measurable amounts of noradrenaline (NA) and dopamine (DA). This study examined the contribution of the amygdaloid catecholaminergic systems to the regulation of the adrenal medulla and the ovary. To accomplish this the neurotoxin 6-hydroxydopamine (6-OHDA) was bilaterally injected into the basolateral nucleus of the amygdala (ABL) in cycling rats. The contents of NA and DA in right and left amygdala decreased significantly in lesioned animals with respect to sham lesioned animals, but hypothalamic levels were not different between groups. Administration of 6-OHDA to rats increased the NA, DA and adrenaline (A) contents of the adrenals compared to vehicle treated rats. In addition, lesioned animals showed a significant increase of NA and DA contents in the ovary, although A levels did not differ between groups. Serum oestradiol (O) concentrations were significantly lower in lesioned animals than in controls. These data suggest that the amygdaloid catecholaminergic systems exert an inhibitory effect on catecholamine content of the adrenals and the ovary, and influence the ovarian oestradiol secretion mechanism.

Effect of metyrapone administration in pregnant rats on monoamine concentration in fetal brain.

Studies performed in our laboratory indicate that the adrenal deprivation during gestation can greatly influence the fetal catecholamines development in several cerebral areas. The present study was undertaken to determine whether the administration of metyrapone to pregnant rats affects the content of monoamines in fetal brain at term. To test wether the content of monoamines in fetal brain is regulated, at least in part, by endogenous glucocorticoids, pregnant rats were injected for 5 days prior to delivery with metyrapone, an adrenal 11-beta-steroid hidroxylase inhibitor which crosses the placenta and blocks endogenous glucocorticoid synthesis, or saline. On day 21 of gestation, delivery of all animals was accomplished by cesarean section. The encephalons were extracted and immediately dissected in metencephalon, mesencephalon, diencephalon and telencephalon. Monoamine determination was carried out using HPLC-ED. The results obtained indicate that the metyrapone treatment increases both DA and 5-HT and their metabolites in the brain studied areas.

Neurochemical changes in newborn rat's brain after gestational cadmium and lead exposure.

Gestational administration of cadmium (10 mg/l) and lead (300 mg/l) produced a strong decrease in proteins at birth (-17%) and on day 5 (-31%) as well as in brain lipid amount on both days (-11 and -23%, respectively). At day 5 postnatal the exposure also produced a marked decrease in DNA and RNA concentrations with respect to the control group. On the other hand, we found a significant increase of indoleamine content in all brain areas studied in the cadmium-lead group and so the dopamine and its metabolite in mesencephalon, whereas dopamine levels in metencephalon decreased significantly. This data suggests that gestational and early lactational exposure to low dose of cadmium and lead could produce alterations in monoaminergic metabolism that can place the exposed animal to a significant risk in adulthood.

Testicular alterations in rats due to gestational and early lactational administration of lead.

A solution of lead acetate (300 mg/L) was administered via drinking water to pregnant Wistar rats from day 1 of pregnancy to delivery (Pb-treated day 0 group) or throughout gestation and early lactation (from day 1 to day 5 postnatal) (Pb-treated day 5 group). When the pups were born, four dams and their offspring in each group (control day 0, Pb-treated day 0, control day 5, and Pb-treated day 5) were sacrificed on day 0 (day 0 groups) or on day 5 (day 5 groups). Relative testicular weight and gross testicular structure were not altered by the treatment. The seminiferous tubule diameter and the number of prospermatogonia were reduced by the treatment. Determination of the n-ploidy stage of prospermatogonia indicates that these cells have more proliferative activity in Pb-treated rats than in control rats. On the other hand, the total DNA, RNA, and protein content of the testes in treated rats was significantly reduced, but the DNA: RNA ratio remained unaltered.

Microalbuminuria in essential hypertension: clinical and biochemical profile.

This study aims to evaluate the clinical and biochemical profile associated with the presence of microalbuminuria in a group of essential hypertensive patients referred to a hypertension clinic. A total of 188 non-diabetic, untreated essential hypertensive patients (100 men, 88 women) aged 55.8 +/- 11.7 years are studied. Urinary albumin excretion was determined in two 24-h urine collections. Clinical and biochemical evaluations and 24-h ambulatory blood pressure (BP) monitoring were performed at baseline. Forty-two patients (22.3%) showed an increased urinary albumin excretion rate (20-200 micrograms/min). These patients showed significantly higher values (P < 0.01) for 24-h, daytime and night-time systolic and diastolic BP, compared with essential hypertensives with normal urinary albumin excretion. However, nocturnal reduction in BP did not differ between the groups. Furthermore, patients with microalbuminuria showed significantly higher (P < 0.01) creatinine, serum uric acid and triglycerides, as well as lower high-density lipoprotein (HDL)-cholesterol. In a multiple logistic regression analysis, a 24-h systolic BP > 140 mmHg (odds ratio: 3.19; 95% confidence interval [CI 95%]: 1.44-7.06) and a serum creatinine > 88 mumol/L (odds ratio: 3.08; CI 95%: 1.39-6.84) were the two factors associated independently with increased urinary albumin excretion. We conclude that, in essential hypertensive patients, the presence of microalbuminuria is associated with elevated BP, but not with its circadian pattern. Likewise, microalbuminuria is associated with the degree of renal impairment, and with increased uric acid and triglycerides and decreased HDL-cholesterol.

Decreased health care quality associated with emergency department overcrowding.

The objective of this study was to assess the influence of overcrowding on health care quality provided by emergency departments (ED). The study was carried out in an urban, university tertiary care hospital. All patients seen at the internal medicine unit (IMU) of the ED who returned during the following 72 hours, and those who died in the ED rooms were included in the study. During a consecutive period of 2 years (104 weeks), we prospectively quantified the number of weekly visits, revisits and deaths. We calculated revisit and mortality rates (in respect of percentage of all visited patients) for each week. Correlation between the number of weekly visits, and revisit and mortality rates was assessed using a simple linear regression model. We consigned 81,301 visits, 1137 revisits and 648 deaths; mean (+/- SD) number of weekly visits, revisits and deaths were 782 (68), 10.93 (3.97) and 6.23 (3.04) respectively; weekly revisit rate was 1.40% (0.48%) and weekly mortality rate was 0.79% (0.36%). We observed a significant, positive correlation between mortality rates and weekly number of visits (p = 0.01). Although a similar trend was also found for revisit rates, such an increase did not reach statistical significance (p = 0.06). It is concluded that since revisit and mortality rates constitute good health care quality markers, present data demonstrate that ED overcrowding implies a decrease in the health care quality provided by it.

The first report on human cases serologically diagnosed as Japanese encephalitis in Indonesia.

Although Japanese encephalitis (JE) virus was isolated from mosquitos in 1974, human JE cases have never been reported in Indonesia in spite of the prevalence of anti-JE antibodies among human and pig populations as well as abundant JE vector mosquitos. In this report, we describe serological diagnosis of JE cases in Bali. Indonesia. using IgM-capture ELISA both on serum and cerebrospinal fluid (CSF) of the patients. In the first series of our investigation (Series 1), we examined serum specimens from 12 patients with clinical diagnosis of viral encephalitis, meningitis or dengue hemorrhagic fever (DHF), and found 2 possible JE cases. In the next series (Series 2), we examined both serum and CSF from encephalitis patients and gave laboratory diagnosis of JE. One of them was suspected to have concomitant or recent infection with dengue virus, probably type 3. These results strongly indicated that JE has been prevalent in Bali, Indonesia.

[Study of mortality in a medical unit of emergency department: incidence, causes and consequences]. / Estudio de la mortalidad en un servicio de urgencias de medicina hospitalario: incidencia, causas y consecuencias.

OBJECTIVES: To define the mortality pattern in a medical unit of emergency department (ED) and to know the satisfaction of relatives with ED provided care. PATIENTS AND METHODS: We computed the number of patients visited and dead from 1989 to 1996. From all patients dying during 1996, we recorded clinical and epidemiological data and we interviewed the patients' family to know their satisfaction with ED provided care. RESULTS: Whole mortality rate was 0.71 (0.15)% X (SD) with an annual increase of 10.4% (r = 0.78, p < 0.05). The clinical profile of patient dying at ED is an individual of advanced age, with a poor quality of life, and in whom the death was expected when arrived to ED. From the family interview, 61% of cases preferred that their relative was dying in the hospital, and 88% were satisfied with ED provided care. CONCLUSIONS: Although the annual mortality rate has progressively increased in ED, family satisfaction with the received care is good.

Retrospective study of radiographic changes in athletic bulls with orthopedic disorders / Estudo retrospectivo das alterações radiográficas de touros atletas com doenças ortopédicas

The objectives of this study were to demonstrate the lesions that affect athlete bulls and to correlate the disorders with weight, age, affected limb and region of the limb. The present study was accomplished using radiographic images of athletic rodeo bulls collected from the medical and surgical records of the large animal service at the veterinary hospital. Radiographic images were evaluated for 136 bulls that were taken care of at the Veterinary Hospital, ranging in age from 4 to 13 years, with an average weight of 800kg and proven prior physical activity through participation in rodeos. The chi-square or Fisher's exact test was used to assess the association between the studied variables. It was observed that 71.6% of the bulls studied and suffering from lameness had radiographic lesions, predominantly in experienced animals. Enthesopathy in starter and experienced bulls, septic arthritis in starter bulls, and fractures and degenerative joint disease in experienced bulls were the most frequent radiographic lesions diagnosed. The region of limb where the majority of radiographic changes occurred was the digits. Risk factors and occurrence of diseases of the locomotor system in athletic bulls are similar to those in sport equines.(AU)

O objetivo desse trabalho foi demostrar quais lesões acometem touros atletas, correlacionando as desordens com peso, idade, membro e região afetada. O presente estudo foi realizado utilizando radiografias de touros atletas de rodeio, após levantamento dos prontuários clínicos e cirúrgicos do serviço de grandes animais de um hospital veterinário. Foram avaliadas radiografias de 136 touros que haviam sido atendidos em tal hospital, com idade variando de quatro a 13 anos, com média de peso de 800kg e realizavam participação em rodeios. Para avaliar a associação entre as variáveis estudadas foi utilizado o teste exato de Fischer e o Qui-quadrado. Observou-se que 71,6% dos touros estudados que claudicavam, apresentavam lesões radiográficas, predominantemente em animais mais experientes. A entesiopatia em todos os animais, artrite séptica nos touros iniciantes, fraturas e doença articular degenerativa nos touros mais experientes, foram as alterações radiográficas mais frequentes. As regiões com maior ocorrência de lesões radiográficas foram os dígitos. Os fatores de risco para ocorrência de doenças no sistema locomotor de touros atletas são diversos, similares aos que ocorrem nos equinos atletas.(AU)

Role of hysteresis in stomatal aperture dynamics.

Stomata are pores responsible for gas exchange in leaves. Several experiments indicate that stomata synchronize into clusters or patches. The patches' coordination may produce oscillations in stomatal conductance. Previous studies claim to reproduce some experimental results. However, none was able to explain the variety of behavior observed in the stomatal dynamics. Recently, Ferraz and Prado suggested a realistic geometry of vein distribution. Although it reproduces the patches, no oscillation was observed and the patches remain static. Without exploring significant details, the authors stated that hysteresis in stomatal aperture could explain several experimental features. In this paper, the hysteresis hypothesis is further explored through the concept of hysteretic operators. We have shown that the hysteresis assumption is sufficient to obtain dynamical patches and oscillations in stomatal conductance. The robustness of this hypothesis is tested by using different hysteresis operators. The model analysis reveals a dependence between the period of oscillation in stomatal conductance and the water deficit between the leaf and the environment. This underlying feature of the model might inspire further experiments to test this hypothesis.