Prevalence and upper limit of cardiac hypertrophy in professional cyclists

The term athlete's heart refers to an increased left ventricular mass. Few studies have assessed the prevalence and normal upper limit of cardiac hypertrophy in highly trained cyclists and this was the aim of this study. A group of 40 professional road cyclists [mean age 26 (SD 3) years] who had participated in European competitions for 3–10 years, were evaluated at the beginning of the 1992–93 season. Evaluation included a clinical history and physical examination, one and two-dimensional echocardiography, 12-lead resting electrocardiogram and a graded exercise test. Determination of the left ventricular mass index (LVMI) was performed using Devereux's formula with correction for the body surface area. Systolic and diastolic blood pressure were measured at rest and at peak exercise. Of the group 23 cyclists (58%) presented a LVMI greater than 130 g · m^–2, 21 cyclists presented a diastolic ventricular thickness equal to or greater than 13 mm, with a superior limit of 19 mm; 3 cyclists presented asymmetrical septum hypertrophy; and the relationship between posterior wall and left ventricular diastolic radius was equal to or greater than 0.45 in 14 cases (35%). Electrocardiographic abnormalities of ST-T segment were seen in only 1 subject. No correlation was found between the degree of ventricular hypertrophy and arterial blood pressure. We concluded that these professional cyclists showed a high prevalence of cardiac hypertrophy (58%). The distribution of this hypertrophy was concentric in 20/33 and asymmetric in 3/23 of the subjects with left ventricular hypertrophy. The electrocardiograms were normal in 98% of the subjects.     

Induction of autonomous endosperm in Lupinus luteus,Helleborus niger and Melandrium album by in vitro culture of unpollinated ovaries

Autonomous division of the endosperm was induced by in vitro culture of unpollinated ovaries or placenta-attached ovules in Helleborus niger, Lupinus luteus and Melandrium album. The induction frequencies for the three species were 50%, 10–20% and 0.1%, respectively. The endosperms contained up to 20 free nuclei; only a few ovules with 80–420 endosperm nuclei were found. Induction of autonomous division of the endosperm, which is unusual in amphimictic plants, was observed in three new species. No embryos appeared in the ovules. This suggests a developmental independence of the endosperm from the embryo in the culture of unpollinated ovaries or ovules.     

Comparison of ccd of F, parDE of RP4, and parD of R1 using a novel conditional replication control system of plasmid R1

A number of plasmid-encoded gene systems are thought to stabilize plasmids by killing plasmid-free cells (also termed post-segregational killing or plasmid addiction). Here we analyse the mechanisms of plasmid stabilization by ccd of F, parDE of RP4 and parD of R1, and compare them to hok/sok of R1. To induce synchronous plasmid loss we constructed a novel plasmid replication-arrest system, which possesses the advantage that plasmid replication can be completely arrested by the addition of IPTG, a non-metabolizable inducer. Using isogenic plasmid constructions we have found, for the first time, consistent correlation between the effect on steady-state loss rates and the effect on cell proliferation in the plasmid replication-arrest assay for all three systems. The parDE system had the most pronounced effect both on plasmid stabilization and on plasmid retention after replication arrest. In contrast, ccd and parD both exhibited weaker effects than anticipated from previously published results. Thus, our results indicate that the function and efficiencies of some of the systems should be reconsidered. Our results are consistent with the previously postulated hypothesis that ccd and parDE act by killing plasmid-free segregants, whereas parD seems to act by inhibiting cell division of plasmid-free segregants.     

A comparative dynamic study of the effectiveness of gastric cytoprotection by vitamin A, De-Nol, sucralfate and ulcer healing by pirenzepine in patients with chronic gastric ulcer (a multiclinical and randomized study)

The gastric cytoprotective effects of vitamin A, De-Nol and sucralfate were compared with the effectiveness of pirenzepine in healing ulcer in patients with chronic gastric ulcer. A total of 100 patients was randomized into different groups: the patients were treated with antacids, vitamin A (3 X 50.000 IU), De-Nol liquid (4 X 5 ml), sucralfate (4 X 1 g) or pirenzepine (3 X 50 mg). The treatment was continued for 4 weeks. At the beginning, 2 and 4 weeks after starting treatment the patients were subjected to endoscopy and the size of the ulcer was measured planimetrically. The ulcer-healing effect of De-Nol liquid was significantly better than that of the antacids (p less than 0.01). Ulcer size was reduced significantly in all groups (p less than 0.01), however, at the end of the study the gastric ulcers were smallest in the De-Nol treated group (p less than 0.001). The dynamics of ulcer healing in the second week was most favourable in the patients receiving vitamin A (p less than 0.01). The present data point to the cytoprotective effects of De-Nol liquid, vitamin A and sucralfate and to their ability of healing chronic gastric ulcers.     

Evidence for the development of tolerance to PGF2 alpha on the ethanol-induced gastric mucosal damage

PGF2 alpha, 100 micrograms/kg intraperitoneally, applied 30 min before 1.0 ml intragastric ethanol (96%) exerts cytoprotective effect on the gastric mucosal membrane. After a week long pretreatment of the animals with 0.25; 0.5 and 1.0 mg/day PGF2 alpha resulted in a diminishing cytoprotective effect. The gastric tissue cAMP level raised simultaneously and after the PGF2 alpha pretreatment with the taming cytoprotection the cAMP level diminished parallel in a dose dependent manner. It is assumed that after PGF2 alpha pretreatment the density of the cellular PGF2 alpha receptors decreases, according to the observed phenomenon.     

Study of the imprinting and overlap of insulin and concanavalin-A at the receptor level in a protozoan (Tetrahymena) model system

In a protozoan (Tetrahymena) model system, insulin treatment produced a long-term imprinting which upon re-exposure to the hormone resulted in an enhanced binding of the hormone. Insulin pretreatment produced similar effect with regard to the binding of concanavalin-A. Concanavalin-A could only induce a short-term imprinting for itself and was not capable at all of inducing imprinting for insulin. Based on the results of this study it appears that the binding of the sugar component of the receptor, which can be achieved also by lectin, is not sufficient to induce imprinting but the whole (hormone) molecule is needed.     

Influence of the conformational state on the isoelectric points of rat brain synaptosomes, mitochondria and mitoplasts

The isoelectric points of rat brain synaptosomes, mitochondria and mitoplasts have been determined by using different charged two-phase systems containing dextran and poly(ethylene glycol). The cross-partition diagrams of these organelles show isoelectric points at pH 4.1, 4.5 and 4.7, respectively. The influence of the conformational state of mitochondrial membranes upon their partition in two-phase systems has been studied. Shrunk mitoplasts showed a large change in their partition behavior as reflected by an increased affinity for the lower dextran phase, while shrinkage of mitochondria did not affect their partition. Shrunk mitoplasts showed the same isoelectric point of pH 4.7 as swollen mitoplasts, which indicates that no charge changes occurred on the outer side of the inner mitochondrial membrane during shrinkage of mitoplasts.     

Immunochemical analysis of the membrane proteins of rat liver and Zajdela hepatoma mitochondria

The contents of mitochondrial inner membrane protein complexes were compared in normal liver and in Zajdela hepatoma mitochondria by the immunotransfer technique. Antibodies against core proteins 1 and 2, cytochrome c1, the iron-sulfur protein of Complex III, subunits I and II of cytochrome oxidase, and the alpha and beta subunits of the F1-ATPase were used. In addition, antibodies against a primary dehydrogenase, beta-hydroxybutyrate dehydrogenase, as well as the outer membrane pore protein were used. The results indicate that the components of the cytochrome chain and porin are greatly enriched in hepatoma mitochondria compared to normal rat liver mitochondria. This enrichment was also reflected in the rates of respiration in tumor mitochondria using a variety of substrates. Enrichment of porin may partially account for increased hexokinase binding to tumor mitochondria. In contrast to the respiratory chain components, the F1-ATPase and F0 (measured by DCCD binding) were not increased in tumor mitochondria. Thus, Zajdela hepatoma mitochondria components are nonstoichiometric, being enriched in oxidative capacity but relatively deficient in ATP synthesizing capacity. Finally, beta-hydroxybutyrate dehydrogenase, which is often decreased in hepatoma mitochondria, was shown here by immunological methods to be decreased by only 40%, whereas enzyme activity was less than 5% of that in normal rat liver.     

Ultrastructural changes in Blastomyces dermatitidis after in vitro exposure to lidocaine

Electron microscopic examination of yeasts of Blastomyces dermatitidis, exposed in vitro to concentrations of lidocaine that occur when the drug is used for topical anesthesia, showed that lidocaine rapidly damaged intracellular structures. The extent of damage was dependent on the concentration of drug and length of exposure. The observed ultrastructural changes were very similar to those reported for other drugs that directly damage membranes. This relationship suggests that the antifungal effect of lidocaine is the result of direct membrane damage.     

Studies on chiasma frequency and distribution in two fertile men carrying reciprocal translocations; one with a t(9;10) karyotype and one with a t(Y;10) karyotype

Summary The frequency and distribution of chiasmata was investigated in two fertile carriers of reciprocal translocations, one with a 46,XY,t(9;10)(p22;q24) karyotype and one with a 46,X,-Y,+der(Y),t(Y;10)(q12;q24) karyotype. In both cases the chromosomes involved in the translocation showed an increase in chiasma frequency in comparison to karyotypically normal controls and in both cases this increase was localised, affecting only one interstitial segment of each translocation quadrivalent. In the t(9;10) case chiasmata appeared in substantial numbers in a novel location, the proximal two thirds of 9p, while in the t(Y;10) case chiasmata appeared in a conventional location, the medial region of 10q, but at an increased frequency. Furthermore there was evidence for inter-chromosomal effects in the t(9;10) case.