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Biomedical subjects

S Graves

Publications and source records attributed to S Graves.

67 records · Page 4Linked to original sources
PubMed1979

Limited protection of rabbits against infection with Treponema pallidum by immune rabbit sera.

After intradermal infection of rabbits with 3 x 10(6) Treponema pallidum (Melbourne 1 strain) samples of serum were taken at one, two, three, four, and six months after infection. Normal rabbits were passively immunised with these sera, challenged with intradermal doses (10(4), 10(3), 10(2), 10) of T. pallidum, and the latent periods of infection, lesion diameters, and the number of inoculation sites developing into lesions were observed. The sera taken at three, four, and six months reduced the number of intradermal inoculation sites that developed into syphilitic lesions after challenge with 10 T. pallidum. These same three sera also increased the latent period of infection after challenge with 10(4) T. pallidum. The transfer of 50 ml of immune serum per rabbit over a nine-day period before challenge had very little effect on the course of the challenge infection. Only a low level of immunity in rabbits to this strain of T. pallidum appears to be mediated by immune serum but this small degree of protection did increase with time after infection. Enhanced growth of T. pallidum in the serum-recipient rabbits did not occur, thus suggesting that none of the sera was immunosuppressive.

Animals↗
PubMed1978

Dantrolene sodium: effects on smooth muscle.

The effects of dantrolene sodium on smooth muscle were evaluated in vitro using the guinea pig ileum and the guinea pig vas deferens preparations. Dantrolene irreversibly decreased the strength of the responses of the ileum to acetylcholine, histamine, potassium chloride and electrical stimulation. Doubling the concentration of calcium in the bathing media reduced the effect of dantrolene on all agonists. Dantrolene irreversibly decreased the response of the vas deferens to epinephrine, norepinephrine, acetylcholine and electrical stimulation. Doubling the concentration of calcium in the bathing media reduced the effect of dantrolene on all agonists. Dantrolene seems to depress smooth muscle as it does skeletal muscle. The mechanism of action probably involves the reduction of calcium flux into the muscles.

Animals↗
PubMed1970

Antileptospiral agglutinins produced in rabbits.

Agglutinating antibodies produced in an adult rabbit in response to intravenous injections of live Leptospira sp. (serotype biflexa, strain Waz), consisted of a 19S component (present at day 6 after inoculation) and a 7S component (present at day 6 after inoculation). Both 19S and 7S antibodies persisted in the serum until the conclusion of the observations (day 216). The 19S antibody was completely destroyed by 2-mercaptoethanol but the 7S antibody was only partially sensitive to 2-mercaptoethanol.The serum proteins present in the 19S and 7S serum fractions were determined by immunoelectrophoresis and cellulose acetate electrophoresis. Elution of the serum components from cellulose acetate membranes directly confirmed that the beta-migrating IgM was the 19S serum component with leptospiral agglutinating activity and that gamma-migrating IgG was the 7S serum component with antileptospiral agglutinating activity.

Animals↗
PubMedDate not supplied

Spotted fever group rickettsial infections in Australia.

More than four decades ago, Rickettsia australis was discovered to be the etiologic agent of Queensland tick typhus (QTT), yet many unanswered questions persist about the ecology, epidemiology, and clinical features of this disease. We review 46 previously published cases of QTT along with 16 cases discovered by active surveillance. QTT is usually a mild disease. Patients often have regional lymphadenopathy and eschars. Some have vesicular rashes. Because clinical features overlap, serologic tests are necessary to distinguish QTT from other endemic Australian rickettsial diseases (scrub and murine typhus). Only two tick vectors of R. australis have been identified: Ixodes holocyclus and Ixodes tasmani. Until rickettsiae are isolated from patients in Victoria and Tasmania, it remains unproven that spotted fever group infections in these locations are due to R. australis. However, available serologic, epidemiologic, and clinical data suggest that QTT is not confined to the area in which R. australis was first isolated (Queensland); rather, it occurs along a 3,200-km span of eastern coastal Australia, from tropical to temperate climates.

Adolescent↗
PubMedDate not supplied

Immunization of rabbits with Spirochaeta aurantia does not induce resistance to Treponema pallidum.

Rabbits were immunized with viable Spirochaeta aurantia, a free-living, facultative anaerobic spirochete that is similar in some biochemical characteristics to Treponema pallidum, a parasitic, microaerophilic spirochete. Single and multiple immunizations with living S. aurantia, with or without Freund's incomplete adjuvant, Freund's complete adjuvant, or heat-killed T. pallidum, were carried out over a four-month period. Living S. aurantia was neither toxic nor virulent for rabbits. Immunized rabbits produced a high level of agglutinating antibody to S. aurantia but no antibody to T. pallidum, as determined by the T. pallidum hemagglutination test. Immunized rabbits were challenged with multiple intradermal inoculations of 100 viable T. pallidum (Nichols strain) and compared to unimmunized rabbits similarly infected. Immunization with S. aurantia did not protect against T. pallidum infection. Thus S. aurantia appears not to be suitable as a potential vaccine against infection with T. pallidum.

Animals↗