Host phylogeny and environment shape the diversity of salamander skin bacterial communities.

The composition and diversity of animal-associated microbial communities are shaped by multiple ecological and evolutionary processes acting at different spatial and temporal scales. Skin microbiomes are thought to be strongly influenced by the environment due to the direct interaction of the host's skin with the external media. As expected, the diversity of amphibian skin microbiomes is shaped by climate and host sampling habitats, whereas phylogenetic effects appear to be weak. However, the relative strength of phylogenetic and environmental effects on salamander skin microbiomes remains poorly understood. Here, we analysed sequence data from 1164 adult salamanders of 44 species to characterise and compare the diversity and composition of skin bacteria. We assessed the relative contribution of climate, host sampling habitat, and host phylogeny to the observed patterns of bacterial diversity. We found that bacterial alpha diversity was mainly associated with host sampling habitat and climate, but that bacterial beta diversity was more strongly associated with host taxonomy and phylogeny. This phylogenetic effect predominantly occurred at intermediate levels of host divergence (0-50 Mya). Our results support the importance of environmental factors shaping the diversity of salamander skin microbiota, but also support host phylogenetic history as a major factor shaping these bacterial communities.

Nanostructured nickel oxide films prepared by chemical vapor deposition and their electrochromic properties.

The influence of the deposition conditions on the structural features and electrochromic properties of nickel oxide (NiO) films prepared by chemical vapor deposition has been investigated. NiO films have been prepared on fluorine doped tin oxide (FTO) coated glass substrates from nickel-acetylacetonate precursor and their electrochromic properties have been studied by cyclic voltammetry in a 0.1 M KOH solution at room temperature. Films exhibiting only the NiO phase were obtained at deposition temperatures higher than 450 degrees C in a wide range of reactor pressures (0.13 to 66.6 kPa). Particularly, NiO films prepared at 500-550 degrees C from 0.13 to 53.3 kPa are transparent in nature and exhibit a crystallite size varying from 10 to 60 nm. An appreciable anodic electrochromic change from transparent to black coloured resulted from a very porous surface morphology and film thickness of about 3.5 microm. The electrochromic change was maintained over 3000 switching cycles. Nanostructured 3.5 microm-thick NiO films showed a maximum difference in optical transmittance of about 40% in the near-infrared region. These results make the nanostructured NiO films comparables with those prepared by other deposition techniques.

Fatal case of community-acquired pneumonia caused by Legionella longbeachae in a patient with systemic lupus erythematosus.

Reported here is a rare case of atypical pneumonia due to a non- pneumophila Legionella sp. that occurred in a young patient with systemic lupus erythematosus. In spite of aggressive treatment, the patient died 24 h following admission to the intensive care unit. Legionella longbeachae was cultured from respiratory tract specimens and identified to the genus level by PCR and to the species level by an immunofluorescence test. Since most current laboratory tests for Legionella spp., including urinary antigen and serology, cannot detect infections caused by non- pneumophila Legionella spp., culture on legionella-selective media should be strongly considered when diagnosing immunosuppressed patients with pneumonia.

Diazepam and progesterone produce sexually dimorphic actions on the rat EEG: role of the neonatal sexual differentiation process.

This study was designed to analyse if the effect of diazepam or progesterone on the wakeful rat EEG vary according to sex and neonatal sexual differentiation. Diazepam or progesterone was administered to males, females, neonatally castrated males and neonatally virilised females. Comparisons of drug actions were made versus baseline values. Both compounds produced clear sexual dimorphic responses, males being more sensitive than females. In normal males and neonatally virilised females diazepam produced a clear increase in the absolute power of fast frequencies. In normal females and neonatally castrated males this anxiolytic only produced a moderate increase in the absolute power of the beta 2 band. Regarding interparietal correlation, diazepam produced an increase in males in the alpha, beta 1 and beta 2 bands, while in females this drug caused a reduction in the same bands. Neonatally castrated males or virilised females showed an intermediate pattern. These data suggest that sexual dimorphism in diazepam action depends upon neonatal sexual differentiation. Progesterone, in contrast with diazepam, produced effects on the EEG that were also sexually dimorphic but independent of the sexual differentiation process. This steroid in males induced an increase in the absolute power of the fast bands of the EEG (alpha, beta 1 and beta 2) accompanied by an increased interparietal correlation of the alpha band. In females, progesterone only reduced the interparietal correlation in the fast theta and alpha bands. Data show similarities between diazepam and progesterone effects on the EEG that are discussed in the light of the anxiolytic-like and hypnotic properties of these compounds. A similar mechanism of action for both substances, involving the GABA(A) receptor, is sustained.

EEG bands during wakefulness, slow-wave, and paradoxical sleep as a result of principal component analysis in the rat.

Rat EEG has been empirically divided in bands that frequently do not correspond with EEG generators nor with the functional meaning of EEG rhythms. Power spectra from wakefulness (W), slow-wave sleep (SWS), and paradoxical sleep (PS) of Wistar rats were submitted to Principal Component Analyses (PCA) to investigate which frequencies are covariant. Three independent eigenvectors were identified for SWS: a band between 1-6, an intermediate band between 7-15, and a fast band between 16-32 Hz (90.74% of the variance); two independent eigenvectors were extracted for PS: slow frequencies between 1-6 covarying together with frequencies between 11-16 Hz, and activity between 6-10 covarying together with fast frequencies between 17-32 Hz (80.38% of the variance); four eigen-vectors were obtained for W: 3-7, 8-9, 10-21 and 21-32 Hz (81.47% of the variance). Vigilance states showed significant differences in AP from 1 to 22 Hz. PCA extracted broad bands different for each vigilance state, which included the most representative EEG activities characteristic of them. These results indicate that during SWS, slow oscillations include frequencies up to 6 Hz, and spindle oscillations frequencies down to 7 Hz. No alpha frequencies were identified as an independent band. Frequencies within theta and beta were gathered in the same eigenvector during PS and in different eigenvectors during W suggesting coordinated activation of hippocampal and cortical systems during PS. These bands are consistent with the underlying neurophysiological mechanisms of sleep and wakefulness and with firing frequencies of generators of rhythmic activity obtained in cellular studies in animals.

Organizational and activational effects of gonadal steroid hormones on the EEG of male and female rats.

To analyze organizational and activational effects of sex steroids on adult rat electroencephalographic activity (recorded at postnatal day 100), seven groups were included: males (48)-intact, neonatally or adult castrated; females (64)-intact, ovariectomized and exposed pre- or neonatally to testosterone propionate. In males, neonatal orchidectomy increased beta relative power, whereas both neonatal and adult castration reduced interparietal correlation. In females, prenatal testosterone administration produced higher theta absolute power; theta relative power was higher in all experimental groups, whereas beta1 and beta2 were decreased by prenatal and increased by neonatal virilization; prenatal virilization enhanced, while neonatal virilization and adult ovariectomy decreased interparietal correlation. These data indicate that females are more sensitive to early prenatal than to neonatal organizational effects of sex steroids, and some electroencephalographic features are feminized in castrated males and virilized in perinatally androgenized females.

Mordedura de perro, la rabia y otras infecciones bacterianas / Dog bite, rabies and other bacterial infections

Si se consideran las consultas por mordeduras de mamíferos en los servicios de urgencia, las más frecuentes son por mordeduras de perro (80 por ciento), 6 por ciento por mordeduras de gato, entre un 1-3 por ciento por mordeduras humanas y menos frecuentemente por animales salvajes (roedores, zorros, etc). La mayor parte de las mordeduras de perro son secundarias a provocación, en un porcentaje estimado de un 55 por ciento y se presentan principalmente en cabeza y cuello (67 por ciento). Afectan más a los hombres (53 por ciento) que a las mujeres (43 por ciento). Hay predominio claro de la población pediátrica con una tasa de incidencia de 6,4/1.000 v/s en los adultos un 2/1.000, es decir, es 3,2 veces más frecuente en niños, con un rango de edad que varía entre los 6,2 ñ 4,2 años. Cabe destacar que en los niños menores de cinco años las lesiones se producen principalmente en cabeza y cuello (61 por ciento), siendo menos frecuente en extremidades (29 por ciento) y otras partes del cuerpo (8 por ciento), invirtiéndose esta relación mientras mayor es la edad del niño. De éstas el 10 por ciento de las lesiones requiere sutura quirúrgica y sólo el 1-2 por ciento tiene indicación de hospitalización

Effect of diazepam and sex hormones on EEG of gonadectomized male and female rats.

Waking EEG was recorded from left and right parietals in 60 adult Wistar rats gonadectomized after puberty during 5 days, 1 as baseline, 1 with vehicle and 1 with 10 mg/kg i.m. of diazepam with hormonal treatment (either testosterone propionate, 5-alpha-dihydrotestosterone or vehicle in males and progesterone, estradiol benzoate or vehicle in females). Quantitative EEG analysis showed that: diazepam in gonadectomized males increased absolute power of alpha, beta 1 and beta 2, increased interparietal correlation of delta and decreased interparietal correlation of slow theta, fast theta and beta 1, whereas in gonadectomized females, diazepam additionally decreased slow and fast theta absolute power. EEG effects were not modified by testosterone propionate or 5-alpha-dihydrotestosterone treatment in males. Diazepam plus estradiol rendered the female EEG response similar to the gonadectomized or testosterone-treated males response; diazepam plus progesterone induced the same response in females as in gonadectomized females and additionally induced interparietal asymmetry and decreased interparietal correlation of all EEG bands. Present results and information on the effects of diazepam on interparietal coupling of EEG and demonstrate that the EEG response to diazepam in adult rats is sexually dimorphic and depends on sex as well as on activational effects of gonadal steroids.

Sex differences in EEG in adult gonadectomized rats before and after hormonal treatment.

EEG activity was recorded from the left and right parietal cortex in adult male and female Wistar rats that were gonadectomized (GNX) after puberty during 2 days without and 3 days with hormonal treatment (either testosterone propionate, 5 alpha-DHT or vehicle in males and progesterone, estradiol benzoate or vehicle in females). In contrast to EEG characteristics reported for intact rats, GNX abolished right over left parietal activation in both sexes and, sex differences in EEG interhemispheric correlation and in theta and delta relative power in the right parietal; additionally GNX males showed higher absolute power than females. Hormonal treatment reestablished interparietal asymmetry in both sexes and a lack of sex differences in absolute power, however, it was not enough to reestablish sex differences in delta and theta proportion in the right parietal nor in interhemispheric correlation. Differential effects were obtained with testosterone propionate and 5 alpha-DHT in males suggesting that activational effects of testosterone on EEG are probably exerted through testosterone or its aromatized metabolites. The results of our study indicate that the activational effects of gonadal steroids after puberty are necessary for maintaining sex differences in the EEG of the adult rat.

Waking electroencephalogram activity as a consequence of sleep and total sleep deprivation in the rat.

Effects of 6 hours of total sleep deprivation (TSD) by gentle handling and 6 hours of sleep on the waking electroencephalogram (EEG) activity of 14 Wistar rats were studied during the lights-on portion of the light-dark cycle under two TSD schedules: a) TSD 0800-1400 hours and sleep 1400-2000 hours, and b) sleep 0800-1400 hours and TSD 1400-2000 hours. EEG was recorded monopolarly from left and right parietals referred to ipsilateral reference electrodes. Spectral analysis was performed on samples of waking EEG during TSD (each 30 minutes) and during sleep (each 60 minutes after enforced awakening). The following significant changes were observed: TSD induced a linear increase in the absolute power of delta (1.46-3.42 Hz) and the full band (1.6-24.9 Hz) and produced a decrease in the interparietal correlation of theta. Sleep induced the opposite results. Theta relative power (power in a band expressed as a percentage of total power between 1.46 and 24.9 Hz) showed a circadian effect. It was higher at 1400 hours than at 0800 and 2000 hours after both sleep and TSD conditions. Six hours of TSD were enough to induce significant changes in the waking EEG regardless of position of TSD in the lights-on period of the light-dark cycle.