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Biomedical subjects

C Russell

Publications and source records attributed to C Russell.

At least 109 records · Page 6Linked to original sources
PubMed1984

The effects of cyclosidimine, a peripheral vasodilator drug, on blood pressure and heart rate in healthy subjects.

Cyclosidimine is a new vasodilator drug with a direct action on vascular smooth muscle. Oral administration of 2.5, 5.0 and 7.5 mg in five normal volunteers had no effect on blood pressure in the supine position but reduced systolic and diastolic pressure in the erect position. In both positions heart rate was significantly greater after cyclosidimine than after placebo. Propranolol prevented the increases in heart rate produced by cyclosidimine which then produced greater reductions in blood pressure.

Adult↗
PubMed1983

Streptococci isolated from the bloodstream and gingival crevice of man.

One hundred and twenty six strains of streptococci isolated from the bloodstreams of 123 hospital in-patients--55 with endocarditis--and 255 strains isolated from the gingival crevices of 66 volunteers were characterised. Species isolated were Streptococcus mitior, S. sanguis, undifferentiated viridans streptococci, S. salivarius, S. milleri, S. mutans, S. bovis and S. faecalis. There was no significant difference between the distribution of species in blood and in the gingival crevice. S. mitior and S. sanguis were found less frequently in blood than their presence in the gingival crevice would have suggested, whereas S. milleri was found more frequently. This may indicate that S. milleri is more invasive or that it enters the bloodstream from sources other than the gingival crevice.

Endocarditis, Subacute Bacterial↗
PubMed1983

Evolutionary and social aspects of disease.

There are important interactions between disease and organic evolution, between disease and cultural evolution, and between all three. Social behaviour influences disease and is influenced by it. Disease and disease mortality are woven into the complex of behavioural and physiological reactions to the stresses of overpopulation, which act to reduce population size. These principles are illustrated with reference to a number of diseases, including vitamin D imbalance, phenylketonuria, lactose intolerance, malaria, sickle cell anaemia, favism, plague, yellow fever, syphilis, ergot poisoning, kuru, and the sweating sickness.

Agriculture↗
PubMed1981

Self-efficacy expectancies, response-outcome expectancies, emotionally based expectancies, and their relationship to avoidant behavior and its reduction through therapy.

Investigated the relationship of four types of expectancy to snake avoidant behavior and its reduction through modeling. Response-outcome expectancies are beliefs about the consequences of a behavior; self-efficacy expectancies are beliefs about one's ability to perform the behavior. Intellectually based expectancies are views of oneself or the world that are perceived to be accurate representations of reality; emotionally based expectancies are views of oneself or the world that may be perceived as inaccurate or irrational by the person who holds them. Experiments I and II investigated the relationship of intellectually and emotionally based versions of both response-outcome expectancies and self-efficacy expectancies to snake avoidant behavior. It was found that all four expectancy variables correlate significantly with behavior on a snake avoidance task. Self-efficacy expectancies are not clearly better predictors of behavior than are response-outcome expectancies. Experiment III found that all four variables are changed as a consequence of modeling. It was concluded that a four-variable expectancy model is necessary to explain avoidant behavior.

Animals↗
PubMed1981

Bacteriocin production by Streptococcus salivarius strain P.

A bacteriocin, streptococcin sal-P, was isolated by freeze-thaw elution from cultures of Streptococcus salivarius strain P grown on tryptic soy agar plus 1% neopeptone. The inhibitor could also be extracted with either 7 M urea of 1 M NaCl from cells grown on this medium, but little activity was recovered from cells grown in liquid media of from the supernatants of these cultures. Streptococcin sal-P was found to be a proteinaceous substance of molecular weight approximately 8000. It was remarkably stable at extremes of pH or temperature and appeared to adsorb nonspecifically to both sensitive and resistant bacterial cells and also to cellulose membranes. The range of its inhibitory activity was almost entirely against Gram-positive bacteria, particularly streptococci, including strains of S. pyogenes and S. sanguis, but not S. mutans or group D streptococci. Streptococcin sal-P was bactericidal for actively metabolizing susceptible strains.

Bacteriocins↗
PubMed1979

The natural history of violence.

In the past, human violence was associated with food shortage, but recently it has increased even in relatively well-fed societies. The reason appears from studies of monkeys under relaxed, spacious conditions and under crowding stress. Uncrowded monkeys have unaggressive leaders, rarely quarrel, and protect females and young. Crowded monkeys (even well-fed) have brutal bosses, often quarrel, and wound and kill each other, including females and young. Crowding has similar behaviour effects on other mammals, with physiological disturbances including greater susceptibility to infections. All this appears to be a regular response to overpopulation, reducing the population before it has depleted its natural resources. Human beings, like monkeys and other mammals, need ample space, and become more violent when crowded. Human history is marked by population cycles: population outgrows resources, the resulting violence, stress and disease mortality cuts down the population, leading to a relief period of social and cultural progress, till renewed population growth produces the next crisis. The modern population crisis is world-wide, and explains the increase of violence even in well-fed societies. The solution to the problem of violence is to substitute voluntary birth control for involuntary death control, and bring about relaxed conditions for a reduced world population.

Aggression↗
PubMed1979

Factors affecting adhesion of bacterial to a tooth in vitro.

The initial adhesion of oral bacteria to a tooth in vitro was examined. The organisms were grown in broth with and without sucrose, and suspensions made either in broth or a modified Ringer's solution. The tooth used was either dry or coated with natural or synthetic saliva. Adhesion was determined by counting organisms removed from the tooth surface by simple washing or by sonication. It was found that the firmest bonding occurred when a dry tooth was immersed in a suspension of bacteria in Ringer's solution; the prior growth of the organisms in the presence of sucrose did not affect adhesion. It was concluded that instantaneous irreversible adhesion of bacteria to a tooth occurs without the need for active metabolism, and that this process is inhibited by the presence of competing organic substances which probably produce a surface-conditioning film.

Corynebacterium↗