Highly conserved Z and molecularly diverged W chromosomes in the fish genus Triportheus (Characiformes, Triportheidae).

The main objectives of this study were to test: (1) whether the W-chromosome differentiation matches to species' evolutionary divergence (phylogenetic concordance) and (2) whether sex chromosomes share a common ancestor within a congeneric group. The monophyletic genus Triportheus (Characiformes, Triportheidae) was the model group for this study. All species in this genus so far analyzed have ZW sex chromosome system, where the Z is always the largest chromosome of the karyotype, whereas the W chromosome is highly variable ranging from almost homomorphic to highly heteromorphic. We applied conventional and molecular cytogenetic approaches including C-banding, ribosomal DNA mapping, comparative genomic hybridization (CGH) and cross-species whole chromosome painting (WCP) to test our questions. We developed Z- and W-chromosome paints from T. auritus for cross-species WCP and performed CGH in a representative species (T. signatus) to decipher level of homologies and rates of differentiation of W chromosomes. Our study revealed that the ZW sex chromosome system had a common origin, showing highly conserved Z chromosomes and remarkably divergent W chromosomes. Notably, the W chromosomes have evolved to different shapes and sequence contents within ~15-25 Myr of divergence time. Such differentiation highlights a dynamic process of W-chromosome evolution within congeneric species of Triportheus.

First cytogenetic studies of the genus Heptapterus (Actinopterygii, Siluriformes): karyotype differentiation and review of cytogenetic data on the Heptapteridae family.

The Neotropical fish Heptapterus mustelinus, collected in the Pindorama stream of the upper Paraná River basin (Brazil), was studied cytogenetically, verifying 54 chromosomes (26m + 18m + 4st + 6a). This diploid number has not been reported among the Heptapteridae that have been studied to date. Unlike most species of the family, there were multiple Ag-nucleolar organizer regions (NOR) and heterochromatin present in the centromeric region of most of the chromosomes of the complement, being Chromomycin A(3) (CMA(3)(+))/4',6-diamidino-2-phenylindole (DAPI(-)) in nine chromosomal pairs, besides the one that coincides with the Ag-NORs. The data presented in this work reveal a different path in the karyotypic evolution of H. mustelinus when compared to the others Heptapteridae genera.

Rat testicular structure and ultrastructure after paracetamol treatment.

The morphological modifications of Wistar rat testicles were investigated for animals treated with paracetamol. The rats (n = 6) received a single dose of 4.4 mmol/kg paracetamol, while controls (n = 6) received the same volume of physiological solution. After 5, 10 and 50 days, the rats were perfused with Karnovsky's fixative and processed by routine methods for light and electron microscopy. Some altered seminiferous tubules were found, as well as a few degenerating tubules. Within the tubules, Sertoli cells appeared fragmented while the spermatids showed unusually well-developed rough endoplasmic reticulum and Golgi complexes and had irregularly compacted chromatin. Morphologically altered late spermatids were found retaining a larger volume of residual cytoplasm than spermatids of controls. An indirect cause of alterations was also suggested based on the occurrence of dilated blood vessels and edema.

A case of pemphigus vulgaris successfully treated with single filtration plasmapheresis: a correlation of clinical disease activity with serum antibody levels.

We report a patient with pemphigus vulgaris (PV) successfully treated with single filtration plasmapheresis. A 40-year-old man with PV was started on therapy with prednisolone (PSL). Although the dosage of PSL was doubled, and both cyclosporin A (CyA) and pulse therapy were added, the disease was not controlled. After single filtration plasmapheresis began, most of the eroded lesions on the trunk reepithelialized. A switch to double filtration was followed by recurrence. Finally, additional treatments with single filtration plasmapheresis were required to obtain remission. To evaluate the efficacy of the treatment, circulating antibodies were measured by immunofluorescence (IIF) and enzyme-linked immunosorbent assays (ELISAs) using recombinant desmoglein (Dsg) 3. IIF titer and the ELISA scores correlated with the clinical disease activity. It is suggested that ELISA was more sensitive than IIF.

Antibody to acetylcholine receptor in canine and human myasthenia gravis: differential cross-reactivity with human and rabbit receptor.

Anti-acetylcholine receptor (AChR) antibody (ab) was found in the serum of a dog with acute myasthenia gravis (MG) by the use of Cowan 1 strain Staphylococcus aureus to bind radiolabeled anti-AChR ab-AChR immune complexes. Fifteen months later, when the dog was in remission, there was only a very low level of the anti-AChR ab. These observations strengthen the contention that anti-AChR ab is important in the pathophysiology of myasthenia gravis. Higher titers of the canine ab were measured with rabbit than with human AChR, whereas 17 human MG sera, selected to represent a wide range of anti-AChR ab titers, were all more reactive with human AChR. The degree of cross-reactivity of human anti-AChR ab with rabbit AChR varied widely, indicating a heterogeneous population of anti-AChR ab molecules in human myasthenia gravis sera.