<Emphasis Type="Italic">Helicobacter pylori</Emphasis> genome variability in a framework of familial transmission

Background  

Helicobacter pylori infection is exceptionally prevalent and is considered to be acquired primarily early in life through person-to-person transmission within the family. H. pylori is a genetically diverse bacterial species, which may facilitate adaptation to new hosts and persistence for decades. The present study aimed to explore the genetic diversity of clonal isolates from a mother and her three children in order to shed light on H. pylori transmission and host adaptation.     

Age related induction of platelet-derived growth factor A-chain mRNA in normal human fibroblasts

We have previously found that stimulation of normal neonatal fibroblasts with PDGF or EGF leads to a transient induction of PDGF A-chain mRNA and the synthesis of PDGF-AA proteins. This finding may imply the existence of an autocrine feedback mechanism to amplify the mitogenic signal under certain conditions. We have now studied the PDGF-BB mediated PDGF A-chain induction in a set of fibroblasts from young and old donors to clarify if the levels of induction are correlated to the donor age and the replicative capacity of the cells. The PDGF A-chain induction was found to be reduced in cells from old donors compared with cells from embryonic and neonatal donors. The different cell strains were also characterized further with respect to PDGF receptor expression and PDGF binding properties. PDGF β-receptors were found to be enhanced in old donor cells strains, whereas the PDGF α-receptors showed more variability in expression between the strains. The PDGF A-chain mRNA induction was also decreased or absent in late passage human fibroblasts (senescent cells) when compared with early passage cells. These data suggest that the PDGF A-chain mRNA induction is regulated by an age related mechanism in human fibroblasts. © 1994 Wiley-Liss, Inc.     

Absorption, metabolism, and excretion studies of carbon 14- and tritium-labeled derivatives of a ketomethylene containing tripeptide

Tritium and Carbon 14 analogs of the angiotensin converting enzyme inhibitor ketoACE were synthesized and their oral absorption, metabolism and excretion in rats were investigated. KetoACE, a ketomethylene analog of the tripeptide Bz-Phe-Gly-Pro, was slowly absorbed at a 35% level upon oral administration. It is rapidly eliminated from the blood with a half-life of about 10 minutes. Its excretion is primarily via the bile duct and it is excreted as 80% unchanged drug. The only identified metabolite consisting of 5-10% of the excreted radioactivity was determined to be the reduced ketoACE in which the ketone group was reduced to a hydroxyl.     

Effect of sprint cycle training on activities of antioxidant enzymes in human skeletal muscle

Hellsten, Ylva, Fred S. Apple, and Bertil Sjödin.Effect of sprint cycle training on activities of antioxidantenzymes in human skeletal muscle. J. Appl.Physiol. 81(4): 1484-1487, 1996.The effect ofintermittent sprint cycle training on the level of muscle antioxidantenzyme protection was investigated. Resting muscle biopsies, obtainedbefore and after 6 wk of training and 3, 24, and 72 h after the finalsession of an additional 1 wk of more frequent training, were analyzedfor activities of the antioxidant enzymes glutathione peroxidase (GPX),glutathione reductase (GR), and superoxide dismutase (SOD). Activitiesof several muscle metabolic enzymes were determined to assess the effectiveness of the training. After the first 6-wk training period, nochange in GPX, GR, or SOD was observed, but after the 7th week oftraining there was an increase in GPX from 120 ± 12 (SE) to 164 ± 24 µmol ^· min^{1 ·} gdry wt¹(P < 0.05) and in GR from 10.8 ± 0.8 to 16.8 ± 2.4 µmol ^· min^{1 ·} gdry wt¹(P < 0.05). There was no significantchange in SOD. Sprint cycle training induced a significant(P < 0.05) elevation in the activity of phosphofructokinase and creatine kinase, implying an enhanced anaerobic capacity in the trained muscle. The present studydemonstrates that intermittent sprint cycle training that induces anenhanced capacity for anaerobic energy generation also improves thelevel of antioxidant protection in the muscle.

     

Study of antimicrobial activity amongLactobacillus helveticus strains using three different assays

The antimicrobial activity of 18Lactobacillus helveticus strains as well as one control strain, the bacteriocin producingLactobacillus helveticus 481, was tested with three different inhibition assays. FourLactobacillus helveticus strains had antimicrobial activity against seven otherLactobacillus helveticus strains and twoLactobacillus delbrueckil strains while the remaining sevenLactobacillus helveticus strains were indifferent. Inhibition was also observed againstLactococcus andLeuconostoc species, due to production of organic acids or hydrogen peroxide. The strains with the highest antimicrobial activity produced a heat sensitive proteinacious bacteriocin with a narrow species activity spectrum against only thermophilicLactobacillus strains.