Search PubMed⌕ Search

Biomedical subjects

P Perrin

Publications and source records attributed to P Perrin.

At least 163 records · Page 9Linked to original sources
PubMed1988

Enhancement of antigen-specific interleukin 2 production by adding liposomes to rabies antigens for priming.

Antigen-specific IL-2 production was assessed, using splenocytes from rabies immune mice incubated for 24 h with rabies virus antigen. The antigenic material used for in vivo priming was either purified glycoprotein from rabies virus, or the inactivated virus. The time between priming, harvesting and restimulation of the splenocytes was 7 days. It was found that when antigenically inert liposomes were injected, together with antigenic material, to the prospective splenocyte donor mice, IL-2 production was enhanced. This augmentation was observed particularly when priming was performed with the inactivated rabies virus.

Animals↗
PubMed1988

Interleukin-2 production in vitro: a new approach to the study of rabies vaccine immunogenicity as appraised by testing different glycoprotein presentations.

When injected as an immunosome presentation (molecules anchored to preformed liposome), rabies glycoprotein (GP) is capable of protecting animals against rabies either before or after viral infection. The presentation of the GP molecules in the correct form seems to be essential for the induction of antirabies protection. This condition must be taken in account in the making-up of a rabies subunit vaccine. In order to study the relationship between the immune responses induced by the rabies GP and its protective activity, different presentations of the GP were prepared. Purified glycoprotein molecules were associated under different physical forms: liposome-anchored, self-aggregated (rosettes) and associated with the viral lipids (virosomes). These presentations appeared different on electron microscopy. They also exhibited differences in the expression of an immunodominant epitope and in their protective activity. The non-specific immune response, as appraised by interferon production and natural cytotoxicity, was induced at a high level only by the purified viral particles. Specific immune responses (namely virus neutralizing antibody and interleukin-2 production) was induced at high levels only by the viral particle and by the liposome-anchored glycoprotein. A parallelism has previously been established between protection by glycoprotein preparations and interleukin-2 production in primed mice splenocytes. This suggests that the measure of interleukin-2 production in vitro could be used to evaluate the capability of a rabies antigen to induce a T-cell response and to confer protection.

Animals↗
PubMed1988

Interleukin 2 increases protection against experimental rabies.

Vaccination with either whole inactivated rabies virus or immunosome (rabies glycoprotein anchored on liposomes) induces a high level of interleukin 2 (IL 2) production after in vitro specific stimulation of splenocytes from primed mice (9). On the contrary, infection with a live rabies virus does not specifically induce the production of IL 2: splenocytes from ill mice previously infected with wild rabies virus cannot be specifically stimulated by rabies antigens, whereas they can be non-specifically stimulated by a mitogen (Concanavalin A (Con A]. When injected in mice, exogenous IL 2 (purified rat IL 2 or human recombinant IL 2) exhibits an adjuvant effect on rabies virus vaccine or subunit vaccine tested in a pre-exposure potency test (NIH test). When injected in hamsters, according to a post-exposure potency test (infection with a wild rabies virus followed by vaccination), IL 2 has no adjuvant effect on the rabies vaccine. Nevertheless, when injected alone, IL 2 protects thirty to fifty percent of the infected animals treated (1 hour, 3 and 7 days post-infection) with 10 international units of human recombinant IL 2.

Animals↗
PubMed1988

Avoidance of base runs in switch regions of immune-system genes.

Mouse immunoglobulin (Ig) switch-region sequences are anti-"runny"; that is, they have a smaller amount of their total bases in homonucleotide tracts ("runs") than would be expected if each nucleotide in the sequence were a random selection from a pool of the composition of the region. The switch sequences involve the first intron of rearranged Ig heavy-chain genes; this intron differs strikingly from the succeeding ones, which are "runny" (have more bases than expected in runs). Switch regions are the only category of sequences so far found to be antirunny by statistical test. This sequence characteristic is related to the presence in switch sequences of repeating heteronucleotides. We suggest that the resulting base dispersion and increased complexity favor more specific interactions between sequences, which may be advantageous in recombinational processes such as switching and translocation.

Animals↗
PubMed1988

[Mass screening or early detection of cancer of the prostate by echography].

Mass screening of prostatic cancer by transrectal ultrasonography would result in between 600 and 2,500 negative biopsies for one positive biopsy, depending on the quality of the ultrasonographic image obtained. It is clear that such a procedure is not profitable. Early detection of prostatic cancer is profitable in a male population over the age of 50 with benign prostatic enlargement. For one positive biopsy, there would be 7 to 25 negative biopsies. In our opinion, a 4 to 16% yield justifies endorectal ultrasonography to look for a malignant prostatic tumor and is fully justified in men scheduled to undergo surgery on an adenoma of the prostate.

Adenocarcinoma↗
PubMed1988

[Otologic signs and early diagnosis of Turner syndrome. Reevaluation of 30 cases].

In most occasions the Turner's syndrome is diagnosed on the basis of severe growth retardation. But the possibility of an effective treatment of short stature requires earlier a diagnosis. Among the other signs, the importance of ORL signs is underestimated. A group of 30 patients has been analysed to determine their precise extension. The external ears are frequently prominent, low-set and/or posteriorly rotated. Frequency and chronicity of otitis media is highlighted by hypoacousy of the transmission type. The perception pathology is far less common and seems being independent of middle ear pathology. A abnormal development of the 1st branchial arch is likely to explain the auricular pathology in view of the frequently associated anomalies of the palate and the dental articulation. One must clearly consider the diagnosis of Turner syndrome in the case of chronic auricular pathology associated with low linear velocity in a young girl allowing for earlier diagnosis.

Adolescent↗
PubMed1987

CpG and TpA frequencies in the plant system.

Higher plant nuclear sequences reveal avoidance of CpG and TpA doublets. Chloroplast sequences avoid the TpA doublet in all codon positions. The chloroplast genome is not methylated but codon positions II-III and untranslated regions avoid CpG. The mitochondrial genome, also unmethylated, avoids CpG in all codon positions. We therefore deduce that methylation is not sufficient to explain CpG avoidance in the higher plant systems. Other factors must be taken into account such as amino acid composition, codon choices and perhaps stability of the DNA helix.

Base Sequence↗
PubMed1987

Directional fixation of mutations in vertebrate evolution.

We have made pairwise comparisons between the coding sequences of 21 genes from cold-blooded vertebrates and 41 homologous sequences from warm-blooded vertebrates. In the case of 12 genes, GC levels were higher, especially in third codon positions, in warm-blooded vertebrates compared to cold-blooded vertebrates. Six genes showed no remarkable difference in GC level and three showed a lower level. In the first case, higher GC levels appear to be due to a directional fixation of mutations, presumably under the influence of body temperature (see Bernardi and Bernardi 1986b). These GC-richer genes of warm-blooded vertebrates were located, in all cases studied, in isochores higher in GC than those comprising the homologous genes of cold-blooded vertebrates. In the third case, increases appear to be due to a limited formation of GC-rich isochores which took place in some cold-blooded vertebrates after the divergence of warm-blooded vertebrates. The directional changes in the GC content of coding sequences and the evolutionary conservation of both increased and unchanged GC levels are in keeping with the existence of compositional constraints on the genome.

Animals↗
PubMed1987

The association of the rabies glycoprotein with liposome (immunosome) induces an in vitro specific release of interleukin 2.

BALB/c mice were primed by receiving a unique intraperitoneal injection of rabies virus antigens presented as complete inactivated virus (P.V. strain) or as purified glycoproteins either in the aggregated form or in physical combination with liposomes (i.e., in the form of "immunosomes"). The splenocytes of these mice were restimulated, 6-15 days after priming, in culture with rabies virus antigens, and antigen-specific IL-2 production was measured. It was found that rabies antigens presented as immunosomes were as active as the inactivated virus, whereas equivalent amounts of purified glycoproteins were inactive. The optimal amounts of rabies immunosomes used for priming was found to be 0.5 to 0.05 micrograms per mouse.

Animals↗
PubMed1987

A collaborative study of an experimental kit for rapid rabies enzyme immunodiagnosis (RREID).

Six laboratories took part in a study to assess an experimental kit for the diagnosis of rabies using the rapid rabies enzyme immunodiagnosis (RREID) technique. The test is based on the immunocapture of rabies antigens present in homogenized brain specimens, followed by enzyme immunoassay. A total of 1253 specimens from various geographical locations and 27 animal species were tested with the RREID technique, and also with the fluorescent antibody test (FAT), which was used as a reference method. For 1220 specimens the results in RREID and FAT were the same (651 positive and 569 negative-concordance: 97.4%). However, the RREID technique appeared to be less sensitive, since 22 (3%) of the 673 specimens that were positive with FAT were negative with RREID. The RREID test is therefore specific and convenient and is a useful tool for epidemiological studies and for laboratories not equipped with an ultraviolet microscope.

Animals↗
PubMed1987

[Polyethylene glycol in cytological puncture of the prostate].

Advantages of the use of polyethylene glycol (Fix-Frot solution) in prostate cytology were evaluated during a comparative study between a preliminary series of 75 examinations using conventional cytology techniques and a second series of 52 examinations using polyethylene glycol. The percentage of blank punctures decreased from 22.6 to 3.8%. Fixation was optimal and immediate; hemolysis of punctured red cells is ensured and use of Pananicolaou's stain allows very high quality analysis. The excellent sensitivity of prostate puncture cytology and its lack of complications place this procedure at the head of diagnostic explorations of prostate. Nevertheless, prostate cytology is difficult to perform and requires the availability of a very experienced cytologist.

Biopsy, Needle↗