Morphological analysis of Trichomycterus areolatus Valenciennes, 1846 from southern Chilean rivers using a truss-based system (Siluriformes, Trichomycteridae).

Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA) and discriminant function analysis (DFA). It is hypothesized that populations must segregate morphologically from each other based on the river basin that they were sampled from, since each basin presents relatively particular hydrological characteristics. Significant morphological differences among the three populations were found with PCA (ANOSIM test, r = 0.552, p < 0.0001) and DFA (Wilks's λ = 0.036, p < 0.01). PCA accounted for a total variation of 56.16% by the first two principal components. The first Principal Component (PC1) and PC2 explained 34.72 and 21.44% of the total variation, respectively. The scatter-plot of the first two discriminant functions (DF1 on DF2) also validated the existence of three different populations. In group classification using DFA, 93.3% of the specimens were correctly-classified into their original populations. Of the total of 22 transformed truss measurements, 17 exhibited highly significant (p < 0.01) differences among populations. The data support the existence of T. areolatus morphological variation across different rivers in southern Chile, likely reflecting the geographic isolation underlying population structure of the species.

The child and adolescent first-episode psychosis study (CAFEPS): design and baseline results.

OBJECTIVE: The child and adolescent first-episode psychosis study (CAFEPS) is a multicenter, two-year, longitudinal project aiming to evaluate different clinical, neuropsychological, neuroimaging, biochemical, immunological, and genetic variables and treatment and prognostic factors in these patients. This paper describes the methods and rationale behind the study and the general characteristics of the sample. METHOD: At six different centers, from March 2003 through November 2005, we consecutively recruited 110 patients, ages 9-17 years, who presented with a first psychotic episode. Controls were recruited from the same geographic areas and were matched for gender and age. RESULTS: Patients had lower socioeconomic status (SES) (p=0.018) and parental years of education (p<0.001) than controls. The percentage of patients recruited increased with age (p<0.001) and there was a higher percentage of males (p<0.001). The total mean PANSS score was 89.03+/-20.1, the positive score 23.8+/-6.5 and the negative score 20.02+/-8.8. There were no significant differences between the genders with respect to age, parental years of education, SES, or scores in premorbid adjustment or general functioning. There were statistically significant positive correlations between age and positive symptoms and between all PANSS subscales and the Disability Assessment Schedule, and negative correlations between positive symptoms and global functioning. Diagnoses after the baseline evaluation were: psychotic disorder not otherwise specified (NOS) 35.5%, schizophreniform disorder 24.5%, mood disorder with psychotic symptoms 22.7%, schizophrenia 10%, schizoaffective disorder 2.7%, and other psychotic disorders 4.5%. Patients had worse premorbid adjustment (p<0.001) and global functioning (p<0.001) than controls after controlling for SES. CONCLUSIONS: Infancy and adolescence adjustment and global functioning are lower in children and adolescents with psychotic disorders than in controls, severity of symptoms are related to general disability, and the most frequent diagnoses are psychotic disorders NOS.

Karyotype and nuclear DNA content of Trichomycterus areolatus (Siluriformes, Trichomycteridae)

Cytogenetic analysis of Trichomycterus areolatus, collected from the Tijeral and Huilma Rivers in southern Chile has shown a diploid chromosome number of 2n = 54, a fundamental number of FN = 106, and a karyotypic formula of 44m + 8sm + 2st. Intra-individual polymorphism of chromosome number (2n = 54, 55 and 56) in specimens from the Huilma River has also been documented, providing further evidence of the occurrence of this phenomenon in Trichomycterus. The karyotype exhibited large chromosome pairs: metacentric pairs 1 (relative length 7.54 percent), 2 (5.75 percent) and 3 (5.09 percent), submetacentric pair 23 (5.25 percent), and subtelocentic pair 27 (5.28 percent). Nuclear DNA content analysis showed an average value of 5.04 ± 1.09 pg/nucleus. This DNA content is higher than the mean value described for other species in this genus.

Pindolol, a beta-adrenoceptor blocker/5-hydroxytryptamine(1A/1B) antagonist, enhances the analgesic effect of tramadol.

The ability of pindolol, a beta-adrenoceptor blocker/5-hydroxytryptamine(1A/1B) antagonist, to enhance the clinical antidepressant response to selective serotonin re-uptake inhibitors is generally attributed to a blocking of the feedback that inhibits the serotoninergic neuronal activity mediated by somatodendritic 5-hydroxytryptamine (5-HT)(1A) autoreceptors. The current study examined the ability of pindolol to enhance the analgesic effect of tramadol, an atypical centrally-acting analgesic agent with relatively weak opioid receptor affinity and which, like some antidepressants, is able to inhibit the re-uptake of 5-HT in the raphe nuclei. Racemic pindolol (2 mg/kg, s.c.), rendered analgesic a non-effective acute dose of tramadol (10-40 mg/kg, i.p.) in two nociceptive tests: a hot plate test in mice and a plantar test in rats. Moreover, (+/-)8-OH-DPAT (0.125-1 mg/kg, s.c.), a selective 5-HT(1A) agonist, reduces the analgesic effect of tramadol in the same tests. These results suggest an implication of the somatodendritic 5-HT(1A) receptors in the analgesic effect of tramadol and open a new adjuvant analgesic strategy for the use of this compound.