Differential proliferative response of the ventral prostate and seminal vesicle to testosterone replacement

We have investigated epithelial cell proliferation and the rate of glandular recovery of the ventral prostate (VP) and seminal vesicle (SV) promoted by testosterone replacement (TR) in castration-induced regressed glands. Adult male Wistar rats were castrated and, after 21 days, they were treated with testosterone propionate (4 mg/kg/day). Intact (CT) and castrated rats without TR (CS) were also analysed. VP and SV were processed for histochemistry, morphometric-stereological analysis and immunocytochemistry to determine the PCNA index (PI). After 10 days of TR, the VP weight reached similar to 72% of the CT values, while the SV weight exceeded similar to 17% of the CT values. By the third day of TR, VP and SV presented a mean P1 of 34% and 94% for distal region and 14% and 22% for proximal region, respectively. SV also had more luminal cells PCNA-positive than VP, mainly in the distal region. The PI values fell on days 5, 7 and 10, but were still higher than CT. These findings indicate that epithelial cells from involuted SV are more responsive to TR than those from VP when Stimulated to proliferate and replace the luminal cell population, suggesting a different mechanism regulating cell proliferation in response to androgenic stimuli. (c) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

Ultrastructure of the mature testicular vesicle of Pseudonannolene tocaiensis Fontanetti, 1996 (Diplopoda, Pseudonannolenidae)

The mature testicular vesicles of the species Pseudonannolene tocaiensis have three portions: a peripheral portion; a central portion that is typically secretory and between these two an intermediary portion, a lumen filled with spermatozoa. Both secretory and peripheral portions present the same type of cells. The ultrastructural analysis of the peripheral portion suggests it is involved in hormone synthesis. The secretory portion probably contributes to the production of spermatic fluid, compensating for the absence of male accessory glands in this species. (c) 2007 Elsevier Ltd. All rights reserved.

Mitosis and cell death in the optic lobes of workers, queens and drones of the honey bee (Apis mellifera) during metamorphosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Imposed Optic Flow Characteristics and Intention on Postural Responses

This study examined the influence of both optic flow characteristics and intention on postural control responses. Two groups of 10 adults each were exposed to the room's movement either at 0.6 cm/s (low velocity group) or 1.0 cm/s (high velocity group). All the participants stood in the upright stance inside of a moving room and were informed about the room movement only after the fourth trial as they were asked to resist to its influence. Results revealed that participants from both groups were influenced by the imposed visual stimulus in the first trials, but the coupling strength was weaker for the high velocity group. The request to resist the visual influences decreased visual influences oil body sway, but only for the low velocity group. These results indicate that intention might play a role in stimulus influences on body sway but it is stimulus dependent.

Optic Flow Contribution to Locomotion Adjustments in Obstacle Avoidance

Locomotion generates a visual movement pattern characterized as optic flow. To explore how the locomotor adjustments are affected by this pattern, an experimental paradigm was developed to eliminate optic flow during obstacle avoidance. The aim was to investigate the contribution of optic flow in obstacle avoidance by using a stroboscopic lamp. Ten young adults walked on an 8m pathway and stepped over obstacles at two heights. Visual sampling was determined by a stroboscopic lamp (static and dynamic visual sampling). Three-dimensional kinematics data showed that the visual information about self-motion provided by the optic flow was crucial for estimating the distance from and the height of the obstacle. Participants presented conservative behavior for obstacle avoidance under experimental visual sampling conditions, which suggests that optic flow favors the coupling of vision to adaptive behavior for obstacle avoidance.

Vesicle-micelle transition in aqueous mixtures of the cationic dioctadecyldimethylammonium and octadecyltrimethylammonium bromide surfactants

The vesicle-micelle transition in aqueous mixtures of dioctadecyidimethylammonium and octadecyltrimethylammonium bromide (DODAB and C(18)TAB) cationic surfactants, having respectively double and single chain, was investigated by differential scanning calorimetry (DSQ, steady-state fluorescence, dynamic light scattering (DLS) and surface tension. The experiments performed at constant total surfactant concentration, up to 1.0 mM, reveal that these homologous surfactants mix together to form mixed vesicles and/or micelles, depending on the relative amount of the surfactants. The melting temperature T-m of the mixed DODAB-C(18)TAB vesicles is larger than that for the neat DODAB in water owing to the incorporation of C(18)TAB in the vesicle bilayer. The surface tension decreases sigmoidally with C(18)TAB concentration and the inflection point lies around (XDODAB) approximate to 0.4, indicating the onset of micelle formation owing to saturation of DODAB vesicles by C(18)TAB molecules. When XDODAB > 0.5 C(18)TAB molecules are mainly solubilised by the vesicles, but when XDODAB < 0.25 micelles are dominant. Fluorescence data of the Nile Red probe incorporated in the system at different surfactant molar fractions indicate the formation of micelle and vesicle structures. These structures have apparent hydrodynamic radius RH of about 180 and 500-800 nm, respectively, as obtained by DLS measurements. (C) 2007 Elsevier B.V. All rights reserved.

Vesicle-micelle transition in mixtures of dioctadecyldimethylammonium chloride and bromide with nonionic and zwitterionic surfactants

We have investigated the effect of mixing spontaneously formed dispersions of the cationic vesicle-forming dioctadecyldimethylammonium chloride and bromide (DODAX, with X being anions Cl- (C) or Br- (B)) with solutions of the micelle-forming nonionic ethylene oxide surfactants penta-, hepta-, and octaethyleneglycol mono-n-dodecyl ether, C12En (n = 5, 7, and 8), and the zwitterionic 3-(N-hexadecyl-N,N-dimethylammonio)propane sulfonate (HPS). We used for this purpose differential scanning calorimetry (DSC), turbidity, and steady-state fluorescence spectroscopy to investigate the vesicle-micelle (V-M) transition yielded by adding C12En and HPS to 1.0 mM vesicle dispersions of DODAC and DODAB. The addition of these surfactants lowers the gel-to-liquid crystalline phase transition temperature (T-m) of DODAC and DODAB, and the transition becomes less cooperative, that is, the thermogram transition peak shifts to lower temperature and broadens to disappear when the V-M transition is complete, the vesicle bilayer becomes less organized, and the T., decreases, in agreement with measurements of the fluorescence quantum yield of trans-diphenylpolyene (t-DPO) fluorescence molecules incorporated in the vesicle bilayer. Turbidity data indicate that the V-M transition comes about in three stages: first surfactants are solubilized into the vesicle bilayer; after saturation, the vesicles are ruptured, and, finally, the vesicles are completely solubilized and only mixed micelles are formed. The critical points of bilayer saturation and vesicle solubilization were obtained from the turbidity and fluorescence curves, and are reported in this communication. The solubility of DODAX is stronger for C12En than it is for HPS, meaning that C12En solubilizes DODAX more efficiently than does HPS. The surfactant solubilization depends slightly on the counterion, and varies according to the sequence C12E5 > C12E7 > C12E8 > HPS.

Vesicle-to-micelle transition in dioctadecyldimethylammonium bromide and dioctadecyldimethylammonium chloride dispersions induced by octaethylene glycol n-dodecyl monoether. An isothermal titration calorimetry study

We have used isothermal titration calorimetry to investigate the vesicle-to-micelle transition in dioctadecyldimethylammonium bromide (DODAB) and chloride (DODAC) vesicle dispersions induced by the nonionic surfactant octaethylene glycol n-dodecyl monoether (C12E8) at room temperature. Small and giant unilamellar vesicles were prepared by sonication and without sonication, respectively, of the pure cationic surfactants at low concentrations in water. The titration of 1.0 mM DODAX (X = Cl- and Br-) by a concentrated micellar solution of C12E8 shows that the enthalpy of interaction (DeltaH(obs)) of C12E8 in micellar form with DODAX is always endothermic. The titration curves are understood on the basis of superposition of the enthalpies of partitioning of C12E8 into the bilayer, of micelle formation and of vesicle-to-micelle transformation. The enthalpy, DeltaH(obs), initially increases owing to the incorporation of C12E8 into the vesicle bilayer until the C12E8/DODAX saturation ratio (R-sat) is reached, then DeltaH(obs) decreases, in different ways for DODAB and DODAC, owing to degradation of vesicles and formation of mixed micelles and intermediary structures up to the C12E8/DODAX solubilization ratio, R-sol. Above R-sol only mixed micelles exist. The surfactant solubilization takes place in three stages. All the critical ratios are lower for DODAB than for DODAC, meaning that C12E8 solubilizes more strongly in DODAB for example, R-sat is 0.8 for DODAB and 1.2 for DODAC. Sonication has no significant effect on the transition.

MORPHOMETRIC AND BIOCHEMICAL EVALUATION OF RAT PROSTATE AND SEMINAL-VESICLE FOLLOWING CHEMICAL SYMPATHECTOMY WITH GUANETHIDINE

Selective chemical sympathectomy of the internal genital organs of adult male rats was undertaken by chronic treatment with low doses of guanethidine. Biochemical and morphometric methods revealed that removal of sympathetic innervation prevents fructose secretion in the prostate and seminal vesicle, in addition to promoting reduced efficiency of delivery by the latter.

Fluorometric fiber optic drop sensor for atmospheric hydrogen sulfide

A fluorometric technique based on a liquid drop excited from its interior by an optical fiber is described for the measurement of low concentrations of atmospheric hydrogen sulfide (H2S). A drop of alkaline fluorescein mercuric acetate (FMA) solution is suspended in a flowing air sample stream and serves as a renewable sensor. An optical fiber contained within the conduit that forms the drop, brings in the excitation beam; the fluorescence emission is measured by an inexpensive photodiode positioned close to the drop. As H2S in the sample is collected by the alkaline drop, it reacts rapidly with FMA resulting in a significant decrease in fluorescence intensity, proportional to the concentration of H2S sampled. The chemistry of this uniquely selective reaction has been well established for many years, the present technique permits a simple fast inexpensive near real-time measurement with very little reagent consumption. Even without prolonged sampling/preconcentration steps, limits of detection (LODs) in the double digit ppbv range is readily attainable. (C) 1997 Elsevier B.V. B.V.

Fragment and vesicle structures in sonicated dispersions of dioctadecyldimethylammonium bromide

Dynamic light scattering has been used to investigate sonicated aqueous dispersions of dioctadecyldimethylammonium bromide (DODAB). The hydrodynamic radius (R-H) of the scattering particles and the mean scattering intensity (I) have been monitored as functions of the DODAB concentration and temperature (T). In the dilute regime, the relaxation time distribution of the sonicated dispersion of DODAB is bimodal with the slow mode dominating the distribution. The slow and fast modes are respectively characteristic of vesicles and bilayer fragments with R-H values of 22 and 8.5 nm (25 degrees C) and 20 and 6 nm (50 degrees C), respectively. The total scattered intensity initially decreased with temperature up to 45 degrees C (T-c), above which it was constant; identical behavior was observed for the slow mode intensity, but the fast mode intensity was constant with temperature change, showing that T-c is a property of the vesicles and not of the bilayer fragments. At T-c the slow vesicle mode becomes narrower whereas the fast fragment mode shows no change. on aging, the dispersion showed a slow transition from bimodal to a rather broad single-modal relaxation time distribution. The corresponding R-H was 33.8 nm when measured 10 months after preparation. These results suggest that aqueous sonicated dispersions of DODAB are metastable.

A morphometric ultrastructural study of the seminal vesicle of rats submitted to experimental chronic alcoholism

The effects of chronic alcohol ingestion on the secretory epithelium of the seminal vesicle were studied in rats (Rattus norvegicus). Male adult albino Wistar rats were divided into two groups: alcoholic and control. Tips of the seminal vesicle were removed and prepared for light and electron microscopy. Ultrastructural observations on the epithelial cells of the seminal vesicle showed reduced epithelial cell size, decreased apical secretory vacuoles, irregularly shaped nuclei with deep infoldings, increased lipid droplets and dense bodies, a small number of microvilli covering the cell surface, and signs of degeneration. In addition to the hormonal effects, alcohol may act on the secretory epithelium of the seminal vesicle.