Muscle hypertrophy and fast fiber type conversions in heavy resistance-trained women

Twenty-four women completed a 20-week heavy-resistance weight training program for the lower extremity. Workouts were twice a week and consisted of warm-up exercises followed by three sets each of full squats, vertical leg presses, leg extensions, and leg curls. All exercises were performed to failure using 6-8 RM (repetition maximum). Weight training caused a significant increase in maximal isotonic strength (1 RM) for each exercise. After training, there was a decrease in body fat percentage (p less than 0.05), and an increase in lean body mass (p less than 0.05) with no overall change in thigh girth. Biopsies were obtained before and after training from the superficial portion of the vastus lateralis muscle. Sections were prepared for histological and histochemical examination. Six fiber types (I, IC, IIC, IIA, IIAB, and IIB) were distinguished following routine myofibrillar adenosine triphosphatase histochemistry. Areas were determined for fiber types I, IIA, and IIAB + IIB. The heavy-resistance training resulted in significant hypertrophy of all three groups: I (15%), IIA (45%), and IIAB + IIB (57%). These data are similar to those in men and suggest considerable hypertrophy of all major fiber types is also possible in women if exercise intensity and duration are sufficient. In addition, the training resulted in a significant decrease in the percentage of IIB with a concomitant increase in IIA fibers, suggesting that strength training may lead to fiber conversions.     

Cellular permeation pathways in a leaky epithelium: the human amniochorion

The presence of cellular permeation pathways in human fetal membranes at term was evaluated. Electrical parameters (transepithelial potential [TEP], and conductance [Gt], and intracellular potentials [cell PD]), and water and urea diffusional coefficients (Pdw, Pdu), were determined in Ussing-like chambers. In amniochorion, the TEP was practically 0 (0.1 +/- 0.03 mV), and the Gt very high (144 +/- 14 mS/cm2). The Cell PD of amnion cells was -37 +/- 3 mV. Increasing the [K+] of the amniotic perfusate between 5.8 and 125.8 mM depolarized the cells with a slope of 23 mV. The deletion of Na+ hyperpolarized the cells, whereas amiloride and ouabain depolarized them. The Pdw and Pdu were determined in intact amnion and chorion and in their epithelial cell layers. The Pdw/Pdu ratio in amnion was 4.0, and 7.0 in its cell layer; the ratio in chorion was 2.5, and 3.3 in its cell layer. The amniochorion is a leaky structure, but its cellular layers possess definite transcellular permeation pathways. The ionic conductances in amnion cells are complex, with the Cell PD being determined by at least K+ and Na+ conductances, and ouabain- and amiloride-sensitive pathways. The amnion is a more effective diffusional barrier to water and urea than chorion is; its diffusional characteristics are comparable to those of nystatin-treated lecithin: cholesterol bilayers and the membranes of human erythrocytes.     

Role of percutaneous pelvic node aspiration cytology in the management of bladder carcinoma

Six of the 23 patients with bladder carcinoma who underwent percutaneous pelvic node aspiration biopsy cytology for staging purposes showed positive findings from nodal chains. Pelvic lymphadenectomy revealed no false-positive or false-negative cytologic results. The fine needle aspiration of opacified pelvic nodes under fluoroscopic control is of great diagnostic value, with a high accuracy in detecting nodal extension of bladder carcinoma and providing a rational basis for proper therapy. Positive aspiration results may be accepted as a basis for therapeutic decisions. Since the metastatic involvement of multiple nodes makes any therapeutic treatment as well as cystectomy completely useless, positive aspirations from more than two nodes may spare patients an unnecessary radical surgery.     

Application of Fluorescence Emission for Characterization of Albendazole and Ricobendazole Micellar Systems: Elucidation of the Molecular Mechanism of Drug Solubilization Process

Albendazole (ABZ) and ricobendazole (RBZ) are referred to as class II compounds in the Biopharmaceutical Classification System. These drugs exhibit poor solubility, which profoundly affects their oral bioavailability. Micellar systems are excellent pharmaceutical tools to enhance solubilization and absorption of poorly soluble compounds. Polysorbate 80 (P80), poloxamer 407 (P407), sodium cholate (Na-C), and sodium deoxycholate (Na-DC) have been selected as surfactants to study the solubilization process of these drugs. Fluorescence emission was applied in order to obtain surfactant/fluorophore (S/F) ratio, critical micellar concentration, protection efficiency of micelles, and thermodynamic parameters. Systems were characterized by their size and zeta potential. A blue shift from 350 to 345 nm was observed when ABZ was included in P80, Na-DC, and Na-C micelles, while RBZ showed a slight change in the fluorescence band. P80 showed a significant solubilization capacity: S/F values were 688 for ABZ at pH 4 and 656 for RBZ at pH 6. Additionally, P80 micellar systems presented the smallest size (10 nm) and their size was not affected by pH change. S/F ratio for bile salts was tenfold higher than for the other surfactants. Quenching plots were linear and their constant values (2.17/M for ABZ and 2.29/M for RBZ) decreased with the addition of the surfactants, indicating a protective effect of the micelles. Na-DC showed better protective efficacy for ABZ and RBZ than the other surfactants (constant values 0.54 and 1.57/M, respectively), showing the drug inclusion into the micelles. Entropic parameters were negative in agreement with micelle formation.     

Bacillus thuringiensis CrylAa δ-Endotoxin Affects the K+/Amino Acid Symport in Bombyx mori Larval Midgut

The mechanical properties of brush border membrane vesicles, BBMV, from rabbit kidney proximal tubule cells, were studied by measuring the initial and final equilibrium volumes of vesicles subjected to different osmotic shocks, using cellobiose as the impermeant solute in the preparation buffer. An elevated intracellular hydrostatic pressure was inferred from osmotic balance requirements in dilute solutions. For vesicles prepared in 18 and 85 mosm solutions, these pressures are close to 17 mosm (290 mm Hg). The corresponding membrane surface tension is 6.0 × 10⁻⁵ N cm⁻¹ while the membrane surface area is expanded by at least 2.2%. When these vesicles are exposed to very dilute solutions the internal hydrostatic pressure rises to an estimated 84 mosm (1444 mm Hg) just prior to lysis. The corresponding maximal surface tension (pre-lysis) is 18.7 × 10⁻⁵ N cm⁻¹, and the maximal expansion of membrane area is 6.8%. The calculated area compressibility elastic modulus was 2.8 × 10⁻³ N cm⁻¹. Received: 8 August 1996/Revised: 4 March 1997     

Protein synthesis, ribosomal protein S6 phosphorylation in vitro and the effects of amiloride: SDS gel electrophoresis studies in the Yoshida ascites tumor (AH 130) grown in vivo

Cell-free cytosolic extracts from the Yoshida (AH 130) rat ascites hepatoma cell line, grown in vivo, showed high ribosomal protein S6 kinase activity in vitro, as measured by transfer of 32P to exogenous 40S rat liver ribosomal subunits, in both exponential growing and stationary phase cells. A significant decrease of protein synthesis (3H-leucine incorporation into total cell protein) was found to occur in cells reaching the stationary phase of growth, suggesting that S6 phosphorylation was not tightly coupled to the rate of the intraperitoneal cell growth and of protein synthesis in these tumor cells. When the cell-free cytosolic extracts were prepared from cells exposed to amiloride, at concentrations that inhibit the Na+/H+ exchange, a decrease of S6 kinase activity was observed only in exponential growing cells, suggesting the possibility of coupling of the Na+/H+ exchange with phosphorylation of intracellular proteins in these tumor cells. Actually, stationary phase cells showed unchanged S6 kinase activity under the same conditions, possibly due to the extremely low Na+/H+ exchange activity, previously demonstrated (Cell Biol. Int. Rep., 1985, 9, 1017-1025). The present experiments support the hypothesis that the regulation of protein synthesis is not tightly coupled to phosphorylation-dephosphorylation cycles, at least of ribosomal protein S6, in cells characterized by a rather uncontrolled growth such as the Yoshida (AH 130) rat ascites hepatoma. In this connection, an elevated degree of protein phosphorylation, such as that of the ribosomal protein S6, could be a general phenomenon of neoplastic transformation.     

Genetics of proteome variation for QTL characterization: application to drought-stress responses in maize

The proteome is emerging as an important concept of the post-genome era. Powerful nucleic acid approaches (EST, DNA chips, etc.) are still limited because DNA sequences and mRNA levels are not sufficient to predict the structure, function, amount, and activity of the proteins in the cell. The proteome can now be subjected to large-scale analysis, owing to spectacular progress in the techniques of identification of proteins excised from two-dimensional (2-D) gels. In addition, computer-based analysis of 2-D gels makes it possible to quantify the protein spot intensities, which are commonly genetically variable. The loci controlling these variations may be mapped on the genome (PQLs, Protein Quantity Loci). Beyond the interest for regulatory genetics and molecular biology, the PQL methodology can provide an additional tool for the difficult task of identifying QTLs (Quantitative Trait Loci), in the context of the candidate gene approach. The PQL methodology is presented with the example of the phosphoglycerate mutase variations in maize, and the candidate gene/protein approach is illustrated for traits responsive to drought stress.