A new species of Astyanax (Characiformes: Characidae) from Dolina Água Milagrosa, Rio Paraguai basin, Mato Grosso, Brazil.

A new species of Astyanax is described from the upper Rio Paraguai basin, Mato Grosso State, Brazil. The new species can be distinguished from congeners by having the body intensely yellowish in life (v. silvery, reddish or lightly yellow) and by morphometric and meristics traits. Astyanax dolinae n. sp. cannot be assigned to any of the Astyanax species complex currently recognized for the genus. It is only known from the Dolina Água Milagrosa, a karstic sinkhole lake, entirely fed by groundwater, surrounded by Cerrado, the savannah-like vegetation of central South America.

MSX1 gene polymorphisms in non-syndromic cleft lip and/or palate.

OBJECTIVE: The aim of this study was to investigate the contribution of 6 polymorphic variants of the MSX1 gene in non-syndromic cleft lip and/or palate (NSCL/P). METHODS: Three hundred and fifty-eight individuals (158 NSCL/P cases and 200 controls) were genotyped by TaqMan allelic discrimination using predesigned SNP assays. Statistical analyses were conducted using the software spss 15.0 and the r statistical suite. Haplotype block structure and haplotype frequencies were determined using the Haploview. A P-value of 0.05 and confidence interval of 95% were used for all of statistical tests. RESULTS: The patients with non-syndromic cleft lip and/or palate were characterized by similar distribution of MSX1 genotypes and allele in comparison to subjects without oral clefts (P > 0.05). Two haplotype blocks were constructed with polymorphisms of MSX1 gene and haplotypes formed showed a similar frequency in patients with and without oral clefts. CONCLUSIONS: The present study provides no evidence that MSX1 polymorphisms (rs3775261, rs1042484, rs12532, rs6446693, rs4464513 and rs1907998) play a major role in NSCL/P.

Critical flicker frequency in migraine. A controlled study in patients without prophylactic therapy.

The critical flicker frequencies (CFF) of individuals with migraine with and without aura were determined and compared to those of normal controls. Twenty-six migraine patients, 12 with aura and 14 without aura and 30 healthy controls were included. Migraineurs were tested during a migraine-free period, through both the continuous flicker method (CFM) and the forced choice method (FCM). Migraineurs presented a mean flickering fusion threshold lower than healthy controls with the CFM (40.45 vs. 44.33, respectively; P = 0.019) and with the FCM (34.16 Hz vs. 38.5 Hz, respectively, P = 0.019). Both groups of migraineurs had significantly lower thresholds as compared to controls, migraineurs with aura presenting the lowest thresholds for the fusion of flickering (P = 0.008 and P = 0.0001 with the CFM and the FCM, respectively). Results confirmed and extended previous observations of abnormal flicker fusion thresholds in migraineurs. We hypothesize that this finding might be related to a shorter cortical stimulation silent period.

Influence of intense light stimulation on trigeminal and cervical pain perception thresholds.

Thirty-three migraineurs and 23 healthy controls were submitted to pressure algometry before and after light-induced discomfort was elicited by progressive light stimulation in a monoblind fashion. Pressure algometries were performed on the emergence of the supraorbital, infraorbital, mental and greater occipital nerves, and over the temporal muscles, always throughout the same sequence and from right to left. Measurements were carried out before and immediately after light stimulation and after 10 min of the second algometry. The final result for each site measured at each time-point was the mean of the three measurements. Light stimulation was carried out progressively until light-induced discomfort was reported, to a maximum of 20,000 lux. A heat-blocking glass protected patients' eyes. Migraineurs presented significant and persistent drops in pain perception thresholds after light stimulation, at all sites tested (P = 0.002 to < 0.0001). These drops were not seen in controls, in whom, conversely, a less significant increase was seen on right infraorbital and left temporal muscle sites. Our results indicate that in migraineurs, light may have a relevant role in trigeminal and cervical pain perception thresholds.

Patterns of daily allocation of sleep periods: a case study in an Amazonian riverine community.

Few works already carried out have examined the relative role of genetic and external factors on the determination of the rhythmicity of the human sleep/wake cycle. In order to make a preliminary approach in this field, we investigated the diversity of patterns of allocation of sleep periods among 29 families living at the Combu Island, a socioculturally very homogeneous human group of the Brazilian Amazon. The individuals were interviewed through a questionnaire designed by Horne and Ostberg (1976), with the language of the questions adjusted to the way-of-life of the riverine people. A large predominance of the morning type was observed (95.35%), what constitutes a strong deviation in relation to other populations studied, suggesting the occurrence of a masking effect. The individual scores presented a positive correlation with the age (r = 0.31; p less than 0.01), and a significant intersexual difference was also verified (t = 3.08; p less than 0.01). This intersex difference is explained, in part, by analyzing the socioeconomic patterns of the community. The offspring/parent regression of the individual scores indicated a low dependency between genitors and their direct descendents (p greater than 0.7), and the estimative of heritability obtained (0.14) is artificial, since the offspring/mother and offspring/midparent regression coefficients were negative. Statistically non-significant coefficients of correlation and/or regression showed a highly randomic populational distribution of scores for the Horne-Ostberg's test. Such findings suggest that the intensity of the masking over the sleep/wake cycle varies among human populations, and that the individual tendency towards morningness/eveningness is strongly related to sociocultural factors.