The role of medical counseling in secondary prevention of cancer in the elderly.

In western countries the elderly are those who experience the major impact of cancer, as epidemiologic data clearly show. Thus, secondary prevention of cancer (SPC) in older persons deserves more attention than it has received until now. Target subjects, however, are often reluctant to enter SPC plans.

An in vitro bacterial model of cytotoxicity to living cells caused by dopamine and 6-hydroxydopamine oxidation at physiological pH.

The cytotoxicity of dopamine (DA) and 6-hydroxydopamine (6-OHDA) on living cells, in vitro, has been previously deeply investigated in neuroblastoma cells. This study was designed to explore the possibility to use bacteria as targets for studying DA and 6-HODA cytotoxicity. Both DA and 6-HODA oxidize when added to bacteriological media.

Mueller-Hinton broth undergoes visible oxidative color changes in the presence of peroxidase and hydrogen peroxide.

In the presence of peroxidase and hydrogen peroxide, Mueller-Hinton broth undergoes a slow but clearly detectable color change from pale yellow to dark yellow or brown. An investigation of this phenomenon led to the conclusion that it is the result of the oxidation of tyrosine, a major component of the broth. Indeed, tyrosine has long been known to oxidize upon treatment with peroxidase and hydrogen peroxide.

'Oxygen toxicity' induced by isoproterenol oxidation on living cells. An in vitro prokaryotic model.

Oxygen radical damage is a relevant problem in gerontological research. It has been implicated both in the aging process itself and in aging-related pathologies. Oxygen radicals from catecholamines seem to play an important role in central nervous system and cardiovascular system disorders during aging.

Streptococcus faecalis susceptibility to amiloride depends on medium pH.

Amiloride is one of the major molecular probes in basic and applied investigations on the physiology of cation transport in animal cells. In these cells the drug also exerts growth inhibitory activity. Recently, we discovered that amiloride causes growth inhibition also on bacterial cells.

Whole-cell bacterial peroxidase test with isoproterenol as the hydrogen donor.

The beta-adrenergic compound isoproterenol was used as oxidizable reagent in a whole-cell assay for the detection of bacterial peroxidase activities. Isoproterenol has been shown to constitute a useful reagent for detecting peroxidase activities in enzymatic tests, utilizing standard purified enzymes, and in the microbiological application proposed. The procedure developed is simple and rapid to perform.

Chlorpromazine as permeabilizer and reagent for detection of microbial peroxidase and peroxidaselike activities.

Chlorpromazine was used to perform a test for the detection of microbial peroxidase activities. The compound acts as both a cell permeabilizer and a reagent in the procedure developed which allows the detection of peroxidase and peroxidase like reactions both semiquantitatively in whole cell determinations and quantitatively in cell-free supernatants.

Effect of amiloride on the intracellular sodium and potassium content of intact Streptococcus faecalis cells in vitro.

Amiloride at millimolar concentrations caused marked changes in the growth-dependent intracellular balance of Na+ and K+ in Streptococcus faecalis. These results, whether specific to transport processes or resulting from indirect yet unknown mechanisms, constitute the first evidence of an effect of amiloride on bacterial electrolytes.

In vitro antistreptococcal activity of the potassium-sparing diuretics amiloride and triamterene.

The ionophore antimicrobial agents provide evidence that perturbations of the electrolyte balance of bacterial cells exert a growth-inhibitory activity. Several drugs acting on animal cell membranes have also been shown to be active on bacterial cells. In this paper, we report preliminary susceptibility studies showing that the class of potassium-sparing diuretics acting directly on monovalent cation fluxes on animal cells possesses a selective growth-inhibitory activity on hemolytic streptococci.

Amiloride, a diuretic with in vitro antimicrobial activity.

The effect of amiloride, an inhibitor of passive sodium influx in animal cells, was investigated on the in vitro bacterial growth. Amiloride blocked the growth of different bacterial strains at concentrations ranging from 25 to 1,300 micrograms/ml. While generally the block was bacteriostatic and bacteria, on amiloride removal, recovered their ability to growth, the drug showed a killing activity on hemolytic streptococci.

New method for detecting Epstein-Barr virus association in nonproducer lymphoblastoid cell lines.

Epstein-Barr virus association in nonproducer human lymphoblastoid cell lines can be demonstrated by the presence of the virus genome (nucleic acid hybridization studies) or by the detection of the virus-coded complement-fixing antigen (complement fixation and/or anti-complement immunofluorescent test). This paper describes an enzyme immunoassay for the detection of Epstein-Barr virus complement-fixing antigen and its application to the demonstration of Epstein-Barr virus association in nonproducer lymphoblastoid cell lines. The assay is based on competition for complement between Epstein-Barr complement-fixing antigen and its specific antibody and a probe complex composed of Escherichia coli beta-galactosidase and specific anti-beta-galactosidase antibody.

Competitive enzyme immunoassay for detection of complement-fixing antibodies in diagnostic virology.

A competitive enzyme immunoassay was developed to detect serum complement-fixing antibodies in virus diseases. This assay utilized conglutinin-covered plastic beads as the solid phase to detect specific antibody-antigen complexes that competed for complement with a probe complex comprised of Escherichia coli beta-galactosidase and its specific antibody. Binding to the solid phase is C3bi mediated, and when specific antibody-antigen complexes are not present the probe is bound and an enzymatic reaction ensues.

Inhibition of nonspecific streptococcal coagglutination reactions.

The reliability of latex coagglutination testing for the serological grouping of hemolytic streptococci is limited by the relatively high incidence of false-positive reactions. Pretreatment of streptococcal suspensions with antisera for the various groups that show clumping gives a specific inhibition of the latex agglutination with the true group, whereas the other groups continue to agglutinate aspecifically. The method is rapid and easy to perform, allows the exact grouping of those streptococci giving aspecific reactions, and is also a useful confirmatory test with monoreactive strains.