Cellular and subcellular localization of the small G protein RhoA in the human and rat embryonic and adult kidney

Rho proteins, a subgroup of the Ras GTPase superfamily, control many cellular processes and morphogenetic events by acting as signaling molecules in the transduction pathways of various receptors. Among the "Rho-dependent" receptors are the extracellular matrix- and growth factor-binding sites; these are particularly involved in the modulation of renal development since they control the epithelial-mesenchymal interactions that drive kidney organogenesis. The present study has addressed the immunohistochemical localization of RhoA in developing and adult kidneys of rats and humans because: a) Rho proteins are known to have a morphogenetic role, b) data in the literature on expression of Rho GTPases during mammalian histogenesis and organogenesis are scarce, and c) their involvement in the transduction pathways of receptors is implicated in kidney development. In particular, RhoA peptide was found to be localized in the mesonephric duct and vesicles in both rats and humans; metanephric anlagen were mainly stained in ampullar-derived cells. Periglomerular tubules of fetal and adult kidneys as well as collecting ducts of adult kidneys showed intense staining. Therefore, the present study provides new information on the distribution patterns of RhoA during early stages of mammalian kidney development suggesting that this signaling molecule may take part in epithelial-mesenchymal induction processes that control kidney organogenesis. RhoA expression in adult structures may be linked with renewal of renal epithelial cells and the maintenance of their morphology and polarity.     

Colorectal polyposis with mixed juvenile and adenomatous patterns

Summary An unusual form of colorectal polyposis is described displaying juvenile, adenomatous and mixed patterns in a 17-year-old girl. Although juvenile polyposis is generally considered to be non-neoplastic in nature, in both the present and in other case reports histological findings support a neoplastic nature. Since an increase in the incidence of large bowel carcinomas has been found in subjects with a previous diagnosis of juvenile polyposis, these patients should be considered to be at risk, and submitted to follow up.     

Glial fibrillary acidic protein immunoreactive astrocytes in developing rat hippocampus.

The developmental pattern of glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes was investigated in the hippocampus (subfields CA1, CA3 and CA4) and in the dentate gyrus of male and female rats aged 11, 16, 30, 90 and 150 days by immunohistochemistry associated with image analysis. Analysis was centred on stratum radiatum, a hippocampal area rich in GFAP-immunoreactive astrocytes. The volume of different portions of hippocampus, the number and the size of astrocytes, the intensity of cell body GFAP immunostaining as well as the extension of astrocyte were assessed. A maturation pattern consisting in higher cellular expression of GFAP, an increase in overall cell size and expanding arborisation from the 11th to the 30th postnatal day, followed by stabilisation of these parameters until the 90th day of life, and a subsequent decrease in the oldest age group studied was found. A sex-related different temporal pattern of astrocytes maturation in size and GFAP content was observed in the CA1 subfield only. The increase of GFAP content during pre-weaning ages was less pronounced in females than in males as well as the decrease between the 90th and the 150th day of age. Moreover, the size of astrocytes was larger in females than in males at the 11th and 150th days of life. These findings suggest that hippocampal astrocytes undergo rapid maturation in the 1st month of postnatal life, followed by a slow consolidation of this process until the 3rd month of life. At 5 months of age, there are still dynamic changes in the mature astrocytes, which become slender and thinner probably as a response to the increased volume of hippocampus noticeable at this age.     

Walking modality affects respiratory muscle action and contribution to respiratory effort

We hypothesized that walking at increased speed or increasing gradient might have different effects on chest wall kinematics and respiratory muscle power components, and contribute differently to respiratory effort sensation. We measured the volumes of chest wall compartments by optoelectronic plethysmography, esophageal, gastric and transdiaphragmatic (P _di) pressures, and the sensation of the respiratory effort by a Borg scale in five normal subjects walking both at ascending gradient with constant speed (AG) and at ascending speed with constant gradient (AS). Chest wall kinematics, evaluated by displacement of chest wall compartments, did not show any significant difference between AS and AG. Muscle power, calculated as the product of mean flow and mean pressure, increased similarly, but its partitioning into pressure and velocity of shortening differed in the two modes. A greater increase in the pressure developed by the abdominal muscles (P _abm) (4.06-fold), and in the velocity of shortening of both rib cage inspiratory muscles (v _rcm,i) (2.01-fold) and the diaphragm (v _di) (1.90-fold) was associated with a lower increase in the pressure developed by the rib cage inspiratory muscles (P _rcm,i) (1.24-fold) and P _di (0.99-fold) with AG. Instead, with AS, a lower increase in P _abm (2.12-fold), v _rcm,i (1.66-fold) and v _di (1.54-fold) was associated with a greater increase in P _rcm,i (1.56-fold) and P _di (1.97-fold). A combination of P _abm and v _di during AG (Wald ²=23.19, P<0.0000), with the addition of P _rcm,i during AS (Wald ²=29.46, P<0.0000), was the best predictor of Borg score. In conclusion, the general strategy adopted by respiratory centers during different walking modes does not differ in terms of ventilation, chest wall kinematics, and respiratory muscle power production, whereas it does in terms of partitioning of power into pressure and velocity of shortening, and respiratory muscle contribution to respiratory effort sensation. Combinations of different patterns of flow and pressure generation made the respiratory effort sensation similar during AS and AG modes.     

Specific ultrarush desensitization in Hymenoptera venom-allergic patients.

BACKGROUND: Hymenoptera venom hypersensitivity is an epidemiologically important problem. The only effective treatment in the management of venom-allergic patients with a history of generalized reactions to insect sting is specific immunotherapy. OBJECTIVE: To demonstrate safety and effectiveness of a modified ultrarush desensitization protocol in venom-allergic patients. METHODS: Fifty-seven patients with Hymenoptera venom allergy underwent a specific 1-day ultrarush desensitization by the subcutaneous route, reaching the cumulative dose of 101.1 microg in 2.5 hours. The maintenance dose (100 microg) was administered after 15 days and thereafter once a month. Patients were followed up for a year. Antihistamines were withheld for 15 days before and during desensitization to not underestimate the incidence of adverse effects. RESULTS: All patients but I completed the ultrarush desensitization. (This patient discontinued the treatment because of a hypertensive crisis not related to the desensitization.) The treatment caused a rapid variation of immunological parameters (IgE, IgG4) since the 15th day. After the desensitization, skin prick test results became negative in 15 patients (27%, decrease of 3.5 log), whereas they decreased in 14 patients (25%, decrease of 1 log). Sixty-four percent showed no adverse effects. Only 7% had a mild systemic reaction. CONCLUSIONS: Ultrarush desensitization is an effective and safe therapy in the management of patients with Hymenoptera venom allergy. In fact, it provides a faster tolerance, without significant differences regarding incidence of severe adverse effects, compared with traditional and rush protocols. It can be adopted for all patients, even children and teenagers.     

Drug resistance mutations and newly recognized treatment-related substitutions in the HIV-1 protease gene: prevalence and associations with drug exposure and real or virtual phenotypic resistance to protease inhibitors in two clinical cohorts of antiretroviral experienced patients

This study aimed at identifying HIV-1 protease amino acid changes associated with protease inhibitor (PI) exposure and susceptibility. New amino acid substitutions were correlated with the number of experienced PIs, reaching statistical significance only for those at positions 3, 44, and 74. The correspondence multivariate model demonstrated that > or =3 experienced PIs and substitutions or mutations at positions 3, 46, 54, 73, 74, and 84 were correlated with PI cross-resistance, including resistance for lopinavir and amprenavir in this cohort of patients who were naive for these drugs.     

Ultrastructural analysis of pancreatic acinar cells from mice fed on genetically modified soybean

No direct evidence that genetically modified (GM) food may represent a possible danger for health has been reported so far; however, the scientific literature in this field is quite poor. Therefore, we investigated the possible effects of a diet containing GM soybean on mouse exocrine pancreas by means of ultrastructural, morphometrical and immunocytochemical analyses. Our observations demonstrate that, although no structural modification occurs in pancreatic acinar cells of mice fed on GM soybean, quantitative changes of some cellular constituents take place in comparison to control animals. In particular, a diet containing significant amount of GM food seems to influence the zymogen synthesis and processing.