The Site of Vascular Response to the α-Toxin of Clostridium Perfringens Type A in Skeletal Muscle

The vascular response to the α-toxin of Clostridium perfringens type A, was observed topographically in the cremaster muscle of the rat, in terms of exudation, labelling of damaged vessels by circulating carbon, and in addition histologically for patency of the vascular plexus.It was confirmed that the permeability response is biphasic. The short-lived immediate phase corresponds to that of venular labelling, and the delayed phase reaches its peak rather later than the corresponding phase of capillary labelling. The intensity and extent of these responses are determined by the degree of injury, but their shape and timing, especially in the immediate phase, vary almost as consistently with the duration of exposure to circulating dye or carbon.After the standard dose of toxin, vascular patency is largely unaffected until 24 hours. Apparently irreversible vascular occlusion occurs rather earlier with larger doses. A three-fold reduction of the standard dose proportionately reduces both exudation and capillary labelling but leaves immediate venular labelling unaffected, suggesting that the latter is not dose dependent and therefore non-specific. Prolongation of moderate venular labelling into the middle of the delayed phase may occur at this dosage. Its absence after the standard dose suggests that delayed inhibition of venular reactivity may be occurring.Irregular labelling of venules and small veins persists throughout the delayed phase with doses 2·4 or more times the standard dose. A brief ultramicroscopic survey revealed appearances in both venules and capillaries at 1-2 hours after injury closely comparable to those which have been described for Cl. oedematiens toxin at 6-24 hours.In rats given carbon during the delayed phase, the effective vascular patency 10 minutes later includes half of the labelled capillaries up to 10 μm in diameter. This proportion is little affected by toxin dose, but intensely so when the carbon clearance time is increased, suggesting that such injured microvessels may be a major source of plasma protein exudation.     

Effects of concurrent inspiratory and expiratory muscle training on respiratory and exercise performance in competitive swimmers

The efficiency of the respiratory system presents significant limitations on the bodys ability to perform exercise due to the effects of the increased work of breathing, respiratory muscle fatigue, and dyspnoea. Respiratory muscle training is an intervention that may be able to address these limitations, but the impact of respiratory muscle training on exercise performance remains controversial. Therefore, in this study we evaluated the effects of a 12-week (10 sessions week^–1) concurrent inspiratory and expiratory muscle training (CRMT) program in 34 adolescent competitive swimmers. The CRMT program consisted of 6 weeks during which the experimental group (E, n=17) performed CRMT and the sham group (S, n=17) performed sham CRMT, followed by 6 weeks when the E and S groups performed CRMT of differing intensities. CRMT training resulted in a significant improvement in forced inspiratory volume in 1 s (FIV_1.0) (P=0.050) and forced expiratory volume in 1 s (FEV_1.0) (P=0.045) in the E group, which exceeded the S groups results. Significant improvements in pulmonary function, breathing power, and chemoreflex ventilation threshold were observed in both groups, and there was a trend toward an improvement in swimming critical speed after 12 weeks of training (P=0.08). We concluded that although swim training results in attenuation of the ventilatory response to hypercapnia and in improvements in pulmonary function and sustainable breathing power, supplemental respiratory muscle training has no additional effect except on dynamic pulmonary function variables.     

Primary low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type arising in the urinary bladder: report of 4 cases with molecular genetic analysis

CONTEXT: Primary lymphoma of the urinary bladder is rare. Only 84 cases have been reported in the English literature to date, and none of these cases has had molecular confirmation of clonal immunoglobulin gene rearrangement. OBJECTIVES: To review all cases with primary urinary bladder lymphoma in our records, to classify them using the REAL classification, to confirm their immunophenotype and genotype, and to determine their outcome. DESIGN: We identified 4 cases of primary urinary bladder lymphoma in our medical records from a 30-year period. Immunohistochemical detection of immunoglobulin light chains and molecular analysis of immunoglobulin heavy-chain genes using the polymerase chain reaction were performed on paraffin-embedded material. RESULTS: All patients were older than 60 years. The male-female ratio was 1:3. All patients had a history of chronic cystitis. Histologic features of mucosa-associated lymphoid tissue lymphoma with centrocyte-like cells, plasmacytoid B cells, or both were observed in all cases. Monoclonality of B cells was demonstrated by immunohistochemistry, polymerase chain reaction, or both methods in every case. All patients presented with stage IAE disease, were treated with radiotherapy alone, and have been in continuous complete remission for 2 to 13 years. CONCLUSIONS: Primary bladder lymphomas are usually of low-grade mucosa-associated lymphoid tissue type. They are more common in females and are associated with a history of chronic cystitis. Lymphoepithelial lesions are seen only in association with areas of cystitis glandularis. B-cell clonality is readily demonstrable by immunohistochemistry and/or polymerase chain reaction analysis. Local radiotherapy appears to confer long-term control.     

Flash labelling of S-phase cells in short-term organ culture of normal and pathological human endometrium using bromodeoxyuridine and tritiated thymidine

Normal hyperplastic and malignant endometrial specimens were labelled in vitro with bromodeoxyuridine (BrdU). S-phase cells were stained after DNA denaturation, using a monoclonal antibody to BrdU and an indirect immunoperoxidase method. Various conditions for BrdU uptake, DNA denaturation, and staining were tested. BrdU labelling was compared with autoradiography using tritiated thymidine, with good correlation. Glandular labelling indices of proliferative endometrium were significantly higher than both secretory and hyperplastic endometrium but were similar to carcinoma. Stromal labelling showed the same trend but the differences were not statistically significant.     

Detection and characterisation of the genes encoding glyoxalase I and II from Neisseria meningitidis

Glyoxalase enzymes I and II are involved in a detoxification process consisting of conversion of reactive dicarbonyl compounds (e.g., methylglyoxal) to less reactive hydroxy acids. The structural gene for meningococcal glyoxalase I (gloA) was identified by screening an expression library with a rabbit antiserum. The meningococcal gloA gene consisted of 138 deduced amino acids, with a calculated mol. wt of 15.7 kDa. The DNA and deduced protein sequence of gloA was compared to known sequences of glyoxalase I enzymes and showed high homology with gloA of several eukaryotic and prokaryotic species. Insertion of a gloA-containing plasmid in Escherichia coli increased the host organism's tolerance to methylglyoxal from <2 mM to >4 mM, thus demonstrating its functional identity. A databank search also revealed the presence of a putative gloB gene, encoding glyoxalase II (GlxII), in the recently released genomic sequences of Neisseria meningitidis and N. gonorrhoeae.     

The androgen receptor of the prostate plasma membrane - an hypothesis

The hypothesis that the prostatic plasma membrane sodium pump apparatus functions as a non-genomic androgen receptor is based upon a number of its properties: (1) Androgen enhances the uptake of K(+) into minced rat prostate. (2) Ouabain, a specific inhibitor of Na/K-ATPase activity, strongly opposes the androgenic effect. (3) In non-genomic microsomes, ouabain sensitivity of the enzyme is enhanced by androgen. (4) Kinetic studies show that androgen significantly increases Vmax, Km and energy of activation of the enzyme. (5) Enzyme, treated with [gamma-(32)P]-ATP and then subjected to SDS-PAGE electrophoresis, binds only to its alpha-subunit, but, if treated with [(3)H]-DHT, shows isotope binding to the beta-subunit. (6) [(3)H]-ouabain binding to androgenized enzyme is 5.5 times greater than to the non-androgenized enzyme. (7) Treatment of the enzyme with 10(-9) M DHT enhances by 40% the binding of the ouabain derivative, anthroyl ouabain (AO). (8) Fluorescent spectra appears to show that, upon phosphorylation of the androgenized enzyme, there is a 14% approximation of the two subunits to each other. (9) Except for neuroepithelium, only the epithelium of the prostate has apically located Na/K-ATPase. Preliminary work in other labs suggests that the beta-subunit of the Na/K-ATPase may be required for establishing the polarity of some epithelial cells.