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Biomedical subjects

S Daniel

Publications and source records attributed to S Daniel.

At least 127 records · Page 7Linked to original sources
PubMed1977

Effect of priming infection on serologic response to whole and subunit influenza virus vaccines in animals.

Results from studies in humans demonstrated that the serologic responses to A/New Jersey (NJ)/76 virus vaccines varied according to the age of the vaccine and appeared to be related to previous exposure of vaccinees to the different strains and influenza A virus. Experiments in animals were therefore performed to investigate the role of previous infection on responses to A/NJ/76 virus vaccines. Mice were infected with influenza A viruses representative of the major strains (Hsw1N1, H0N1, H2N2, H3N2) and later inoculated with various doses of whole or subunit A/NJ/76 virus vaccines. Results from experiments in mice demonstrated a low antigenicity of the subunit vaccine in unprimed animals compared with that of whole-virus vaccine; however, the antigenicity of both vaccines was enhanced in mice primed by previous infection with H0 and H1 viruses. In hamsters previously infected with an H3N2 virus, however, the response to only the whole-virus vaccine was enhanced by the priming infection. The responses of the mice were qualitatively more similar to those of humans than were the responses of hamsters.

Adolescent↗
PubMed1976

Recombination of influenza A virus strains: effect on pathogenicity.

Influenza viruses can recombine genetic information, and progeny virus can be selected for desired genetic traits. A newly isolated strain can develop the ability to grow to higher titer in embryonated eggs by acquiring this trait from the AOPR8(HON1) strain, and can be selected by the terminal dilution technique and by treatment with anti-HON1 antisera. In addition to acquiring the ability to grow to high titer, surface antigens may also be transferred, and the progeny can be selected by immunologic methods. It appeared likely that other genes, including those coding for virulence or attenuation might also be exchanged during the recombination procedure. We explored this question by infecting mice with recent strains of H3N2 influenza virus, and with some of their progeny which had been selected for high virus yields from eggs, after recombination with the AOPR8(HON1) virus, a strain known to be virulent for mice. Influenza (H3N2) virus strains A/Scotland, A/Port Chalmers and A/England which were isolated and passaged in embryonated eggs did not cause death when administered intranasally to three-week-old Swiss mice; however, after recombination with the A/PR8(HON1) virus, these viruses become lethal in mice. This acquisition of virulence appears to be secondary to exchange of genetic information from the parent AOPR8 virus. Virus isolated from mice infected with these recombinants is antigenically H3N2, the mice develop anti-H3N2 antibodies.

Animals↗
PubMedDate not supplied

Characterization of a putative pheromone biosynthesis-activating neuropeptide (PBAN) receptor from the pheromone gland of Heliothis peltigera.

The binding of [(3)H]tyrosyl-PBAN28-33NH(2) to pheromone gland membranes of the moth Heliothis peltigera was investigated. The study describes the development of a pheromone biosynthesis-activating neuropeptide (PBAN) radioreceptor assay and demonstrates the presence of a putative PBAN binding site on the pheromone gland. It also describes synthesis of a radioligand and optimization of binding conditions with respect to membrane preparation, number of gland equivalents, kinetics of ligand binding and composition of the binding solution. Binding was found to be optimal when membranes were freshly prepared from frozen glands, incubated at a concentration of one gland equivalent per reaction tube in the presence of 10 mM HCO(3)(-) ions. Equilibrium of ligand binding was obtained after 20 min. Presence of other components such as NaCl, KCl or SH reagents did not have any effect on binding. Binding was found to be saturable, with a K(d) of 5.73 +/- 1.05 x 10(-6) M and a Bmax of 1.85 +/- 0.22 nmol/mg protein. Binding was effectively displaced by unlabeled PBAN1-33NH(2) and PBAN28-33NuEta(2) with a K(i) of 4.3 +/- 1.1 x 10(-6) M and 4.9 +/- 2.6 x 10(-6) M, respectively.

Animals↗
PubMedDate not supplied

Inactivation and partition of human T-cell lymphotrophic virus, type III, during ethanol fractionation of plasma.

Because of concern about the safety of immune globulins prepared for injection, we studied the effects of ethanol fractionation of human plasma on human lymphotropic virus, type III, (HTLV-III) by spiking the products of various fractionation steps with HTLV-III. Tests of inactivation and removal indicated that the ratio of residual live virus in plasma fractions/live virus in starting plasma was about 1 X 10(-15) for precipitate II from which immune globulin for injection is manufactured. The results are reassuring regarding the potential safety of immune globulin.

Deltaretrovirus↗
PubMedDate not supplied

Purification and reconstitution of a recombinant human neurokinin-1 receptor.

Recombinant human neurokinin-1 receptors expressed in insect cells have been purified to near homogeneity by sequential metal-chelating chromatography and gel filtration chromatography. The purified receptor consists of a single polypeptide with an apparent molecular weight of 50 kD as revealed by SDS gel electrophoresis, and exhibits a specific activity of 19 nmol of L-703,606 bound per mg of protein. Immunoblot experiments further confirm the identity of the stained protein band. The purified receptor binds the antagonist L-703,606 with an affinity similar to that of native human neurokinin-1 receptor, and binds the agonist substance P with an affinity similar to that of the low affinity state of uncoupled native receptor. The purified receptor can be reconstituted with membranes from uninfected insect cells, and the reconstitution results in an increased affinity for substance P, consistent with the reappearance of the high affinity state of the receptor for agonist in the presence of endogenous G proteins. These data indicate that the purified neurokinin-1 receptor is functional with respect to agonist and antagonist binding and G protein coupling.

Amino Acid Sequence↗
PubMedDate not supplied

Bacteriological study of pus isolates from neuropathic plantar ulcers associated with acute inflammatory phase.

In this retrospective study, sensitivity of organisms cultured from ulcers of leprosy patients without and with diabetes mellitus, diabetic patients without leprosy and patients with ulcers from other causes was examined. The profile of organisms grown from these groups of patients did not differ significantly. However, there was a high prevalence of organisms like Proteus, E. coli and Enterococcus in the ulcers of leprosy patients indicating faecal contamination of the ulcers. Co-trimaxazole and tetracycline were of little value in the treatment of these ulcers. We therefore recommend that in situations where there is no culture facility, the patients be started on a course of penicillin and gentamycin. If these antibiotics fail, it would be necessary to use more advanced antibiotics like norfloxacin, amikacin and ciprofloxacin.

Adolescent↗