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Biomedical subjects

H Smith

Publications and source records attributed to H Smith.

At least 631 records · Page 35Linked to original sources
PubMed1978

Factors affecting the mobility of plutonium-238 dioxide in the rat.

A major factor influencing the movement of plutonium-238 from the lungs to blood after the intubation of oxide suspensions is the presense of 0.001 micrometer diameter particles. In a polydisperse suspension of particles this fraction increases with time, due it is thought, to fragmentation of larger particles induced by alpha decay. The rate of this process could account for the greater transportability in vivo of plutonium-238 relative to plutonium-239 when the oxides are inhaled. In blood, 0.001 micrometer diameter plutonium-238 oxide particles undergo a rapid reaction to form a low molecular weight species before plutonium is complexed with transferrin and citrate ions. The filtration of this species through the kidneys may explain the observed enhanced urinary excretion of plutonium relative to administered plutonium citrate. The mechanism of urinary excretion and relationship between cumulative urinary excretion and body content for plutonium-238 is similar to that previously observed for plutonium-239, even though different methods of preparation of the oxides were used.

Animals↗
PubMed1978

The effect of specific antiserum on the resistance of Neisseria gonorrhoeae to intracellular killing by phagocytes of human blood.

The high natural resistance of gonococci showing a characteristic 'double highlight' (DH) colonial morphology (Penn, Veale & Smith, 1977b) to intracellular killing by human phagocytes was markedly reduced by addition of rabbit antiserum to the phagocytosis medium or by preincubation of organisms with antiserum. Antisera raised to three different DH gonococcal strains showed a complex pattern of specificity in phagocytosis tests with the homologous organisms and three other DH strains. The effect of antiserum could be neutralized by adsorption with intact organisms or with extracts, prepared ultrasonically, of the homologous strain. Antiserum also promoted the intracellular killing of a strain which had a 'single highlight' colonial morphology (Penn et al., 1977b) and a low natural resistance to phagocytic killing, but adsorption with this strain neutralized the antiserum less consistently than the DH strain. The neutralization of antiserum-mediated promotion of intracellular killing by extracts of organisms naturally resistant to such killing may provide an assay for the aggressins responsible for this resistance.

Adsorption↗
PubMed1978

Peritoneal anaphylaxis in the rat after sensitization with mouse antiserum.

Passive peritoneal anaphylaxis in rats, sensitized with mouse antiserum, had characteristics of an IgE-mediated reaction, in that the serum was heat-labile and pretreatment of the rats with disodium cromoglycate (DSCG), or sodium nivimedone, inhibited the release of both histamine and slow-reacting substance of anaphylaxis (SRS-A). Sodium nivimedone was more potent than DSCG as an inhibitor of histamine release. Peak concentrations of histamine and SRS-A in the peritoneal fluids of the rats, were reached within 2 min of antigen challenge and fell to control levels after 20-30 min.

Anaphylaxis↗
PubMed1978

5-Hydroxytryptamine and rat passive peritoneal anaphylaxis.

Antigen challenge of rats, sensitized by intraperitoneal injection with rat anti-serum, did not result in a detectable increase in the 5-hydroxytryptamine (5-HT) levels in their peritoneal fluids over the background level induced by sensitisation alone. The maximum amount of extravasation produced by intraperitoneal injection of 5-HT into passively sensitised rats was less than that produced by antigen or histamine, and the doses of 5-HT producing these levels of extravasation produced an produced an increase of 5-HT concentrations in the peritoneal fluids. Therefore, 5-HT is unlikely to make much direct contribution to the extravasation produced during rat passive peritoneal anaphylaxis. However, when given intraperitoneally to rats, 5-HT potentiates the extravasation produced by histamine.

Anaphylaxis↗
PubMed1978

Psychological factors in susceptibility to drug-induced extrapyramidal symptoms.

In an effort to identify nonneurobiologic factors in the susceptibility to neuroleptic-induced extrapyramidal symptoms (EPS), the EPS response in 20 patients was correlated with field dependence, self-object differentiation, and premorbid social competence. Only the last proved to be a good predictor, which suggests that psychosocial factors play a role in a patient's EPS response.

Adult↗
PubMed1978

An inherited anomaly of human eosinophils and basophils.

Inclusions staining gray or blue-gray in Romanowsky treated films were found in eosinophils and basophils in a family as an autosomal dominant anomaly without overt clinical effects. Associated with the inclusions were distinctive crystals which were different from the crystalloids of eosinophil granules and from Charcot-Leyden crystals. The restriction of the anomaly to eosinophils and basophils indicates that these are related more closely to each other than to neutrophils and mast cells, and suggests the existence of a separate stem cell for eosinophils and basophils.

Basophils↗
PubMed1978

Association of foetal wastage with influenza infection during ferret pregnancy.

Inoculation of influenza virus into pregnant ferrets during the late gestational period was investigated. Foetal resorption followed intracardial inoculation of a large dose of influenza virus (10(9.4) EBID50) and a 100-fold lower dose caused lower litter sizes at birth. The possible role of fever in foetal resorptions was largely discounted by 2 observations: a non-pyrexic dose inoculated intracardially into the pregnant ferret still had detrimental effects on foetal viability; influenza virus inoculated intranasally caused a pyrexia but did not affect the progeny. The potential of the ferret as a model for studying the possible adverse effects of influenza during pregnancy is discussed.

Animals↗
PubMed1978

Sensitivity to pyrexial temperatures: a factor contributing to virulence differences between two clones of influenza virus.

The influence of pyrexia on the differential persistence of a virulent and an attenuated clone of influenza virus in the respiratory tract of ferrets has been further studied. Clone 64d, an attenuated clone of a recombinant virus (A/PR/8/34-A/England/939/69 (H3N2)) grown in organ cultures of ferret nasal turbinates, was inactivated at pyrexial temperatures more readily than a virulent Clone 7a. In addition, replication of Clone 64d was restricted at pyrexial temperatures to a greater extent than that of Clone 7a in organ cultures of both ferret nasal turbinate and lung tissue. The greater adverse effects of pyrexial temperatures on Clone 64d appears to explain the earlier reduction of upper respiratory tract infection seen in ferrets infected with this attenuated clone. Also, the differential influence of pyrexial temperatures may be the reason for the virtual lack of lung infection with Clone 64d in vivo in contrast to the consistent infection found with Clone 7a. The relevance of these findings to human infection and to markers of attenuation of influenza virus is discussed.

Animals↗
PubMed1977

Evidence favoring the use of anticoagulants in the hospital phase of acute myocardial infarction.

Since the last comprehensive review of anticoagulation in acute myocardial infarction four additional randomized control trials have been reported. The overwhelming majority of all trials favored anticoagulation. Rates of thromboembolism were higher in the control, and hemorrhagic complications in the anticoagulated group. Pooling of all randomized control trials gives mean case fatality rates of 19.6% for the control and 15.4% for the anticoagulated group, a relative reduction of 21% (P less than 0.05 or less than 0.001, depending on the analytic method). Five of six randomized control trials reported "no effect" because the difference favoring anticoagulation was not statistically significant. However, sample sizes in these "negative" papers were too small to protect against missing a 21% reduction in true case fatality rate due to anticoagulation (beta greater than 0.10). All patients who present no specific contraindication should receive anticoagulants during hospitalization for infarction.

Acute Disease↗
PubMed1977

Behaviour in ferrets of swine influenza virus isolated from man.

After intranasal instillation into ferrets, the "swine" influenza virus A/New Jersey/8/76(Hsw1 N1) had a 50% minimal infectious dose similar to that of previously tested A/PR/8-A/England (H3 N2) recombinants virulent and attenuated for man. A/New Jersey produced only a mild upper respiratory tract infection. However, higher titres of virus were recovered from the lungs over a longer period than experienced previously with Asian and Hong Kong virus strains. There was a diphasic pyrexia the second and higher peaks of which correlated with peak titres of virus in lung macerates. These results suggest that A/New Jersey has a pneumotropic potential in ferrets and, if the animal model is valid, possible in man.

Animals↗