Mean arterial pressure,O2-uptake,and muscle force time during dynamic and rhythmic-static exercise in men with high percentages of fast- and slow-twitch fibers

Summary The influence of different percentages of slow-twitch (ST) and fast-twitch (FT) fibers in vastus lateralis on the relationship between mean arterial pressure (MAP) and O₂-uptake ( O₂) with muscle force time (MIpm, ⁶⁰₀ p×t) exerted on the pedal during upright cycling, or during rhythmic isometric contraction (RIC) (only one subject) was studied in three high percent ST men (average 78% ST) (ST group), and in three high percent FT men (average 75% FT) FT group). MAP, or MIpm, was higher and had a steeper linear regression in the FT group than in the ST group at or against the same absolute O₂ during cycling at 60 rpm, or 100 rpm. The relationship between MAP and MIpm, however, was almost the same between both in the FT and ST group, or between both at 60 and 100 rpm. During RIC the slope (y/x) of the linear regression line between MAP and MIpm was close to that during cycling, whereas the slope of O₂ vs. MIpm was much lower. In conclusion, the variations in fiber population in working muscle do not seem to have any effect on MAP. MAP increases with MIpm independent of fiber population and/or fitness ( O₂ max).     

A comparison of the IFA and the ELISA for the demonstration of antibodies against schistosome gut-associated polysaccharide antigens in schistosomiasis

The applicability of two immunodiagnostic techniques was studied for the detection of antibodies against schistosome gut-associated polysaccharide antigens in human schistosomiasis mansoni: the immunofluorescent antibody reaction (IFA) using Rossman's fixed paraffin sections of adult worms and the enzyme-linked immunosorbent assay (ELISA) with a trichloroacetic acid soluble fraction of total adult worm antigens (AWA-TCA).With the IFA, gut-associated polysaccharide antigens could be demonstrated with an anti-IgM conjugate in a high percentage of the sera tested, although false-negative reactions were occasionally recorded. The use of an anti-IgG conjugate resulted in the demonstration of antibodies against additional antigens in the parenchyma of the worm and on the tegument. Specific IgM antibodies were present in higher concentrations in the sera from children than in those from adults.Using AWA-TCA as the antigen preparation in the ELISA, only antibodies against the circulating anodic antigen (CAA) could be demonstrated. Pretreatment of the ELISA-plates with poly-L-lysine to couple AWA-TCA was not necessary. The ELISA was sucessfully applied with anti-Ig, anti-IgG and anti-IgM conjugates. With anti-Ig conjugate the test was very sensitive and gave less false-negative reactions than the IFA. There was a significant difference between Ig, IgG, and IgM titres of children and adults. The use of an immunogalactosidase assay with a fluorogenic substrate in the ELISA, resulted in a test which was able to detect antibodies at ten times higher dilutions than with the immunoperoxidase assay.This investigation received financial support from the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases     

A PCR-based integrated protocol for the structural analysis of the 13th exon of the human beta-myosin heavy chain gene (MYH7): development of a diagnostic tool for HCM disease

Familial Hypertrophic Cardiomyopathy (FHC) constitutes a genetic disease of the sarcomere characterized by a Mendelian pattern of inheritance. A variety of different mutations affecting the at least eight sarcomeric gene products has been identified and the majority of them appear to function through a dominant negative mechanism. Family history analysis and genetic counseling have been widely adopted as integral tools for the evaluation and management of individuals with Hypertrophic Cardiomyopathy (HCM). Genetic testing of the disease has been progressively released into the clinical mainstream, thus rendering the development of novel and potent molecular diagnostic protocols an inevitable task. To this direction, we have evolved an integrated PCR-based molecular protocol, which through the utilization of novel “exonic” primers allows, among others, the structural analysis of the 13th exon of the human β-myosin heavy chain gene locus (MYH7) mainly characterized by the critical for HCM Arginine residue 403 (R⁴⁰³). Interestingly, through a DNA sequencing approach, a single nucleotide substitution from “G” to “T” was detected in the adjacent 13th intron, thus divulging the versatile potential of the present molecular protocol to clinical practice.