Rating of perceived exertion as a tool for prescribing and self regulating interval training: a pilot study

The aim of the present study was to analyse the usefulness of the 6-20 rating of perceived exertion (RPE) scale for prescribing and self-regulating high-intensity interval training (HIT) in young individuals. Eight healthy young subjects (age = 27.5±6.7 years) performed maximal graded exercise testing to determine their maximal and reserve heart rate (HR). Subjects then performed two HIT sessions (20 min on a treadmill) prescribed and regulated by their HR (HR: 1 min at 50% alternated with 1 min at 85% of reserve HR) or RPE (RPE: 1 minute at the 9-11 level [very light-fairly light] alternated with 1 minute at the 15-17 level [hard-very hard]) in random order. HR response and walking/running speed during the 20 min of exercise were compared between sessions. No significant difference between sessions was observed in HR during low- (HR: 135±15 bpm; RPE: 138±20 bpm) and high-intensity intervals (HR: 168±15 bpm; RPE: 170±18 bpm). Walking/running speed during low- (HR: 5.7±1.2 km · h⁻¹; RPE: 5.7±1.3 km · h⁻¹) and high-intensity intervals (HR: 7.8±1.9 km · h⁻¹; RPE: 8.2±1.7 km · h⁻¹) was also not different between sessions. No significant differences were observed in HR response and walking/running speed between HIT sessions prescribed and regulated by HR or RPE. This finding suggests that the 6-20 RPE scale may be a useful tool for prescribing and self-regulating HIT in young subjects.     

Cytochemical Localization of Plasma Membrane Enzyme Markers During Interiorization of Tachyzoites of Toxoplasma gondii by Macrophages

The enzyme activity of Mg-ATPase, Na⁺-K⁺-ATPase, 5'-nucleotidase and NAD(P)H-oxidase was cytochemically detected at the ultrastructural level in mouse peritoneal macrophages infected with untreated and with specific antibody-coated Toxoplasma gondii tachyzoites. The Mg⁺⁺-ATPase and 5'-nucleotidase were distributed throughout the macrophages'plasma membrane but were not observed in the membrane lining endocytic vacuoles containing ingested parasites; however, Na⁺-K⁺-ATPase activity was detected in the macrophages'plasma membrane as well as in the parasitophorous vacuoles that contained untreated or specific antibody-coated parasites. Reaction product, indicative of NAD(P)H-oxidase, was detected in the parasitophorous vacuoles that contained only-specific antibody-coated parasites.     

Phagocytosis of bacteria by polymorphonuclear leukocytes: a freeze-fracture, scanning electron microscope, and thin-section investigation of membrane structure

The changes in membrane structure of rabbit polymorphonuclear (PMN) leukocytes during bacterial phagocytosis was investigated with scanning electron microscope (SEM), thin-section, and freeze-fracture techniques. SEM observations of bacterial attachment sites showed the involvement of limited areas of PMN membrane surface (0.01-0.25μm(2)). Frequently, these areas of attachment were located on membrane extensions. The membrane extensions were present before, during, and after the engulfment of bacteria, but were diminished in size after bacterial engulfment. In general, the results obtained with SEM and thin-section techniques aided in the interpretation of the three-dimensional freeze-fracture replicas. Freeze-fracture results revealed the PMN leukocytes had two fracture faces as determined by the relative density of intramembranous particles (IMP). Membranous extensions of the plasma membrane, lysosomes, and phagocytic vacuoles contained IMP's with a distribution and density similar to those of the plasma membrane. During phagocytosis, IMPs within the plasma membrane did not undergo a massive aggregation. In fact, structural changes within the membranes were infrequent and localized to regions such as the attachment sites of bacteria, the fusion sites on the plasma membrane, and small scale changes in the phagocytic vacuole membrane during membrane fusion. During the formation of the phagocytic vacuole, the IMPs of the plasma membrane appeared to move in with the lipid bilayer while maintaining a distribution and density of IMPs similar to those of the plasma membranes. Occasionally, IMPs were aligned to linear arrays within phagocytic vacuole membranes. This alignment might be due to an interaction with linearly arranged motile structures on the side of the phagocytic vacuole membranes. IMP-free regions were observed after fusion of lysosomes with the phagocytic vacuoles or plasma membrane. These IMP-free areas probably represent sites where membrane fusion occurred between lysosomal membrane and phagocytic vacuole membrane or plasma membrane. Highly symmetrical patterns of IMPs were not observed during lysosomal membrane fusion.     

Chronic-arginine supplementation improves endothelial cell vasoactive functions in hypercholesterolemic and atherosclerotic monkeys

Chronic exposure to l-arginine results in regression of atherosclerotic lesions and reversal of endothelial dysfunction. We investigated whether chronic l-arginine supplementation induces regression of atherosclerotic lesions and reversal of endothelial dysfunction in atherogenic rhesus monkeys and the mechanism which leads to these effects. About 12 male rhesus monkeys were fed 1% cholesterol and 18 g butter for 6 months to create an experimental model of hypercholesterolaemia and atherosclerosis (Group I) and 12 monkeys were fed standard stock diet for 6 months (Group II). After, 6 months these two groups were further divided into 2 sub-groups which in addition to their respective diets were fed 2.5% l-arginine in drinking water for additional 6 months (Group III and Group IV). Systemic nitric oxide (NO) formation was assessed as plasma nitrite and cGMP formation every 3 months. Oxygen free radical (OFR) generation and malondialdehyde production as an index of lipid peroxidation were determined. Changes in isometric tension were compared in isolated ring segments of thoracic aorta from normal and hypercholesterolemic animals.Cholesterol feeding progressively reduced plasma nitrite and cGMP generation (p<0.05). Dietary l-arginine partly restored the levels of plasma nitrite and cGMP (p<0.05) but did not change plasma cholesterol levels. l-arginine significantly reduced aortic intimal thickening, blocked the production of carotid and coronary intimal plaques and completely preserved endothelium-dependent vasodilator function. Further, l-arginine significantly inhibited generation of the reactive oxygen species (ROS) generation and lipid peroxidation.Chronic oral supplementation with l-arginine blocks the progression of plaques via restoration of nitric oxide synthase substrate availability and reduction of vascular oxidative stress. (Mol Cell Biochem 269: 1–11, 2005)     

Mutations in capillary morphogenesis gene-2 result in the allelic disorders juvenile hyaline fibromatosis and infantile systemic hyalinosis

Juvenile hyaline fibromatosis (JHF) and infantile systemic hyalinosis (ISH) are autosomal recessive syndromes of unknown etiology characterized by multiple, recurring subcutaneous tumors, gingival hypertrophy, joint contractures, osteolysis, and osteoporosis. Both are believed to be allelic disorders; ISH is distinguished from JHF by its more severe phenotype, which includes hyaline deposits in multiple organs, recurrent infections, and death within the first 2 years of life. Using the previously reported chromosome 4q21 JHF disease locus as a guide for candidate-gene identification, we identified and characterized JHF and ISH disease-causing mutations in the capillary morphogenesis factor-2 gene (CMG2). Although CMG2 encodes a protein upregulated in endothelial cells during capillary formation and was recently shown to function as an anthrax-toxin receptor, its physiologic role is unclear. Two ISH family-specific truncating mutations, E220X and the 1-bp insertion P357insC that results in translation of an out-of-frame stop codon, were generated by site-directed mutagenesis and were shown to delete the CMG-2 transmembrane and/or cytosolic domains, respectively. An ISH compound mutation, I189T, is predicted to create a novel and destabilizing internal cavity within the protein. The JHF family-specific homoallelic missense mutation G105D destabilizes a von Willebrand factor A extracellular domain alpha-helix, whereas the other mutation, L329R, occurs within the transmembrane domain of the protein. Finally, and possibly providing insight into the pathophysiology of these diseases, analysis of fibroblasts derived from patients with JHF or ISH suggests that CMG2 mutations abrogate normal cell interactions with the extracellular matrix.     

Crohn disease: frequency and nature of CARD15 mutations in Ashkenazi and Sephardi/Oriental Jewish families

Crohn disease (CD), an inflammatory bowel disease, is a multifactorial trait with the highest frequency in Ashkenazi Jewish (AJ) individuals of Central European origin. Recently, three common predisposing CARD15 mutations (R702W, G908R, and 1007fs) and a polymorphism (P268S) were identified. To determine whether CARD15 mutations account for the higher prevalence of CD in AJ individuals, the haplotypes and allele frequencies of the common mutations and variants were assessed in 219 members of 50 AJ and 53 members of 10 Sephardi/Oriental Jewish (SOJ) multiplex families with CD, in 36 AJ patients with sporadic CD, and in 246 AJ and 82 SOJ controls. A higher frequency of CARD15 mutations was found in AJ patients from multiplex families with CD from Central (44.0%) versus Eastern (24.0%) Europe, especially for G908R and 1007fs, and in SOJ patients (34.5%) compared with AJ (10.1%) or SOJ (5.4%) controls. Contrary to expectation, the frequency of the common mutations was slightly lower in AJ patients with CD (30.1%) than in SOJ patients with CD (34.5%). The 702W allele was associated with both the P268 and 268S alleles. CARD15 mutation frequencies were greater in affected sib pairs than in sporadic CD cases but actually decreased in families with three or more affected sibs, raising the possibility of genetic heterogeneity. Similarly, our linkage evidence on chromosome 16 was diminished in the families with three or more affected sibs compared with sib pairs. Screening the CARD15 gene for rare variants revealed five novel changes (D113N, D357A, I363F, L550V, and N852S) of which N852S occurred only in AJ individuals and may be disease predisposing. Also, there was no evidence for increased risk associated with the recently described IVS(+158) single-nucleotide polymorphism. Although the AJ controls appear to have a higher frequency of CARD15 mutations than the SOJ controls, it is unlikely that this difference fully explains the excess frequency of CD in the AJ population.     

Determination of antibiotic resistance and resistance plasmids of clinical Enterococcus species

To determine the antibiotic resistance pattern and resistance plasmids, we studied 23 antibiotic-resistant clinical isolates of Enterococcus spp. which caused infection in Bayindir-Ankara Hospital, Turkey. Biochemical and physiological identification tests were applied by the Vitek system and compared with the results of protein profiles by SDS-PAGE. From 23 isolates, 20 were identified as E. faecalis, 2 as E. faecium and 1 as E. gallinarum. Twenty four antibiotics belong to 10 different groups were used in susceptibility tests. Multiple antibiotic resistance was determined in 10 of 23 Enterococcus spp. Overall resistance to the used antibiotics was 47.3% and low level resistance was 16.6%. Among the isolates tested, 8.7% demonstrated high level gentamicin resistance, 17.4% demonstrated high level streptomycin resistance, and 43.5% demonstrated penicillin resistance. High level vancomycin resistant Enterococcus spp. rate was 34.8%, and 60.9% exhibited low level resistance to vancomycin and teicoplanin. They contain plasmids which varied in numbers between 1 and 11 and the plasmid sizes ranged from 2.08 to 56.15 kb. In curing experiments with acriflavine, two different plasmids were shown in different molecular sizes of 33.49 and 13.6 kb while the first determined glycopeptide and penicillin resistance, the second one determined either glycopeptide or penicillin resistance in two different E. faecalis strains. On the other hand, a 22.58 kb plasmid, determining kanamycin resistance, was detected in an E. faecium strain. After the curing experiments, an elimination of 37.17 and 44.47 kDa protein bands was shown in E. faecium EFA1 and E. faecalis EFA13 in SDS-PAGE, respectively. This survey indicates the increase of antibiotic-resistant enterococci, especially to vancomycin in our hospital isolates.     

Cut-off values for normal sperm morphology and toxicology for automated analysis of rat sperm morphology and morphometry

We used automated sperm morphology analysis to investigate rat sperm morphometry and morphology in Sprague-Dawley and Wistar rats in three research centers to develop normal baseline values for sperm morphometry and to quantify the percentage of morphologically normal sperm in healthy rats. The participating centers were IRSN in Paris, France (Sprague-Dawley rats), University of the Western Cape, South Africa (Wistar rats) and Stellenbosch University (Wistar rats), South Africa. All three centers used identical sperm isolation techniques from the cauda epididymis, the same staining protocols, identical computer-aided sperm morphometry analysis (CASMA) software and microscopes with similar optics. With CASMA, fully automated analysis of the different parts of stained sperm, e.g., head, acrosome, mid-piece, can be performed, many sperm morphometric features can be measured accurately and eventually normal sperm morphology can be defined. We found that it is possible to distinguish sperm morphometric characteristics of Sprague-Dawley and Wistar rats. We also developed cut-off values for evaluating the percentage normal sperm in these two rat strains using the automatic analysis mode. Normal sperm morphology varied between 67 and 74% by contrast with previous findings of > 90%.