Integration of bilateral whisker stimuli in rats: role of the whisker barrel cortices.

Recently, we demonstrated that neural responses within the whisker region of the primary somatosensory cortex (SIw) of rats are profoundly influenced by the spatiotemporal attributes of ipsilateral, as well as contralateral, whisker stimuli. As inactivation of one SIw eliminates in the intact SIw both ipsilaterally evoked responses and the influence of ipsilateral stimulation on contralaterally evoked activity, we proposed that interhemispheric interactions between the SIws may be important for integrating bilateral whisker information. To test whether rats can recognize the bilateral nature of a whisker stimulus, we developed a tactile discrimination task that required rats to conjointly determine distances to a left and a right discriminandum as equidistant or non-equidistant using only their facial whiskers. All rats trained in this task achieved performance levels indicative of an ability to integrate bilateral whisker information. Testing during unilateral, as well as bilateral, inactivation of the SIws indicated that rats rely on both SIws for detecting the bilateral nature of a whisker stimulus. Rats were unable to perform the task without both sets of whiskers, a fact that indicates that the whiskers (and not other modalities) were used to perform this task. The findings presented here indicate that rats can solve a task that requires the conjoint detection of left and right whisker-mediated distance information and implicate the SIws as central to this ability.     

Ossifying fibromyxoid tumor of soft parts

Ossifying fibromyxoid tumors (OFT) of soft parts are very rare neoplasms recently described by Enzinger et al. (1). They usually present as well-circumscribed, slow-growing, asymptomatic subcutaneous masses. A characteristic finding is a fibrous capsule and an incomplete peripheral shell of mature bone. Although most cases behave as benign tumors, a high rate of local recurrences have been described. We describe a 43-year-old male with a perianal subcutaneous tumor of 10 years evolution. The histopathology was compatible with OFT. Due to the subcutaneous location of OFF, both the dermatologist and dermatopathologist need to know about this rare tumor.     

Intestinal microvillous atrophy in a patient with Down syndrome and aganglionic megacolon

Intestinal microvillous disorders are an uncommon cause of severe diarrhea, with very poor prognosis. The authors report the case of a female infant with Down syndrome, aganglionic megacolon, severe diarrhea, and jejunal biopsy with ultrastructural changes consistent with microvillous atrophy. The patient condition improved after a colostomy performed in the setting of the treatment of Hirschprung disease.     

Mouse Sperm Rosette: Assembling During Epididymal Transit,in vitro Disassemble,and Oligosaccharide Participation in the Linkage Material

In many mammals, sperm associations had been observed, but not in the mouse. In this work, mouse sperm rosettes are morphologically described inside the epididymis and during its dissolution in a culture medium. Also characterized are the saccharides present in the linking material. Sperm association and other epididymal actions are supported by sperm during epididymal transit and are verified at the caudal region, suggesting a relation between epididymal transit and sperm maturation. In drops of epididymal content obtained from distal (cauda), but not from proximal (caput and corpus) regions; dissolved in culture medium, rosettes appear to be 10 to 15 motile sperm joined by their heads. After 3 min, sperm progressively detach, disassembling the rosette. These structures are studied by several techniques, including optic, electronic (scanning electron microscopy and transmission electron microscopy), and video microscopy. At the ultrastructural level, a dense network of electron‐dense material was observed between sperm heads, joining them. Based on previous works in rat, several lectins were used to characterize the type of saccharides present in this linking material. To avoid the contact between sperm and epididymal fluid from distal region—that probably exerts an influence on sperm association—a ligature was placed between caput and corpus. This epididymal content isolated from caput did not display any rosettes after 28 days. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

Lymphoepithelioma-like carcinoma of the bladder: three cases with clinicopathological and p53 protein expression study

Lymphoepithelioma-like carcinoma of the bladder is an uncommon neoplasm, of which 49 cases have been described in the English literature, none of which has been studied for p53 protein expression. We studied three muscle-infiltrating cases of this tumor using immunohistochemical, in situ hybridization and polymerase chain reaction (PCR) methods. The three cases were positive for epithelial markers and negative for lymphoid antigens in the tumoral syncytial areas. The intensive infiltrate of small cells was negative for epithelial and positive for lymphoid markers. This population was mainly made up of cytotoxic T-lymphocytes, positive for TIA-1. p53 protein was intensely positive in more than 90% of the epithelial component nuclei, being negative in the lymphoid cells. PCR study did not show mutations on p53. Both lymphocytes and epithelium were negative for Epstein–Barr virus markers, such as the latent membrane protein and EBER (Epstein–Barr-encoded RNA). The prognosis was very good after radiotherapy and chemotherapy treatment, preserving the bladder despite the muscle infiltration. The presence of an intense cytotoxic T-lymphocyte population may be related to this good prognosis. Both aspects, p53 protein status and T-lymphoid population, had never been studied before in bladder lymphoepithelioma-like carcinoma.     

Non-pathogenic Entamoeba histolytica: functional and biochemical characterization of a monoxenic strain

We have cultured under monoxenic conditions and characterized an Entamoeba histolytica clone, MAV-I CINVESTAV (MAV-I), obtained from feces from an asymptomatic carrier. The clone shows the non-pathogenic E. histolytica zymodeme type I, which did not change through the process of monoxenization. Clone MAV-I was non-pathogenic in both in vivo and in vitro tests, and it did not have a functional 112-kDa adhesin. As far as we know, this is the first non-pathogenic monoxenic strain reported. Clone A (strain HM1:IMSS), a highly virulent clone with pathogenic zymodeme type II, and which has the 112-kDa adhesin, was used as a control. Protein patterns from both clones were almost identical in one-dimensional gels. In two-dimensional gels, differences in high-molecular-weight proteins were detected. Clone MAV-I adhered and phagocytosed only 12% of the red blood cells adhered and phagocytosed by clone A. MAV-I trophozoites did not destroy cell culture monolayers and did not produce hepatic abscesses in hamsters. They also showed deficiency in protease activity. The absence of virulence in clone MAV-I correlated directly with the absence of a functional 112-kDa adhesin, supporting the role that this protein plays in virulence.     

Detection of Trypanosoma cruzi and Trypanosoma rangeli infection by duplex PCR assay based on telomeric sequences

We used the species specificity and repetitious nature of subtelomeric kinetoplastida sequences to generate a duplex PCR assay for the simultaneous detection of Trypanosoma cruzi and Trypanosoma rangeli in experimentally and naturally infected triatomine (Reduviid) bugs and in infected human subjects. The assay was species specific and was capable of detecting 1/20th of T. cruzi and 1/4th of T. rangeli cell equivalents without complementary hybridization. In addition, the PCR-based assay was robust enough for direct application to difficult biological samples such as Reduviid feces or guts and was capable of recognizing all T. cruzi and T. rangeli strains and lineages. Because the assay primers amplify entirely different target sequences, no reaction interference was observed, facilitating future adaptation of this assay to an automated format.     

Molybdate repair of molybdopterin deficient mutants from Chlamydomonas reinhardtii

Summary The phenotypically wild strain I₃ of Chlamydomonas reinhardtii, carrying a cryptic mutation at the nit-6 locus, was distinguished from strains 21gr (cryptic mutant at nit-5) and 6145c (wild type) because of the ability of I₃ to grow on nitrate media containing 2mM tungstate.Molybdopterin-cofactor (MoCo) mutants 102 (double mutant at nit-5 and nit-6) and 104 (mutant at nit-4) grew on nitrate media supplemented with high concentrations of molybdate, although final cell densities were 40–60% lower and generation times 3.5 to six fold longer than for wild type. Under these conditions, nitrate reductase (NR) activity of the mutants, when measured either in situ or in vitro, was practically undetectable. The MoCo defective mutant 307 (nit-3) was not molybdate repairable. Although NR activity was not restored in vitro by molybdate in any of the MoCo^– mutant strains, their extracts had free NR-diaphorase subunits together with NR-subunits assembled into high molecular weight species.Our results indicate that: a) nit-4, nit-5 and nit-6 loci are responsible for molybdate processing in the cell; b) nit-3 may encode a component of the pterin moiety biosynthetic route; c) NR subunits can assemble in the presence of an inactive MoCo; d) high concentrations of molybdate can replace partially in vivo but not in vitro the function of nit-4 and the combined function(s) of the nit-5 and nit-6 gene products.     

Cyclooxygenase-2 in normal,hyperplastic and neoplastic follicular cells of the human thyroid gland

This study was undertaken to investigate cyclooxygenase-2 (COX-2) expression in follicular cells of the human thyroid. COX-2 expression was studied immunohistochemically in a total of 174 samples. COX-2 immunoreactivity was confined to the cell cytoplasm with the nuclei remaining unlabelled. COX-2 expression was observed in five cases (17.2%) of normal follicular cells and in one case (16.6%) of solid cell nests. Follicular carcinoma expressed COX-2 more frequently than follicular adenoma (93.4% vs 21.1%) (p0.001). A higher percentage of cases of papillary microcarcinomas up-regulated COX-2 in comparison with all papillary carcinomas (p0.05). However, we could not establish any relationships among COX-2, patients ages or lymph node metastases in papillary carcinomas. COX-2 expression was found in 12 (92.3%) poorly differentiated carcinomas and in 13 (92.8%) undifferentiated carcinomas. We found that COX-2 is not always useful as a marker of malignancy. Our results suggest that COX-2 plays a role in progression of all thyroid carcinomas, but in papillary carcinomas, seems more important only in the early stages. COX-2 expression in the undifferentiated carcinoma deserves special consideration due to its prognosis and to the fact that selective COX-2 inhibitors were found to enhance tumour response to radiation in some studies.