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Biomedical subjects

J Samson

Publications and source records attributed to J Samson.

36 records · Page 2Linked to original sources
PubMed1988

Retinoid-binding proteins in human oral mucosa.

Vitamin A affects epithelial differentiation and growth via at least 3 different binding proteins. The specific delivery of extracellular retinol to target cells is performed by plasma retinol-binding protein (RBP) while cellular retinol- and retinoic acid-binding proteins (CRBP and CRABP) are implicated in the cellular action of the 2 natural retinoids. We have studied the levels of these 3 binding proteins by gel filtration and polyacrylamide electrophoresis in human oral mucosa, epithelium and chorion and compared it to those found in keratinizing human epidermis. The levels of CRABP in oral epithelium were markedly higher (about 4 times) than that of epidermis whereas CRBP was in a similar amount in epithelium chorion, dermis and epidermis. RBP with preserved affinity for retinol, was present in the epithelium of oral mucosa whereas only degraded RBP was detected in epidermis. These results suggest (i) a higher specific retinol delivery and (ii) a distinct cellular metabolism of retinoic acid in the oral epithelium as compared with epidermis. Since cornification occurs when keratinocytes are deprived of retinol, it might be that our observations are linked to the absence of cornification in the human oral mucosa. Further, high levels of CRABP in mucosal epithelium might have therapeutical implications because the synthetic retinoids used in human therapy bind to CRABP.

Adolescent↗
PubMed1988

Racial differences in sports performance.

The purpose of this paper is twofold: (a) to present data on racial differences in sport performance and (b) to comment briefly on theories, hypotheses and studies, whether they be biological, psychological or sociological in nature, that have attempted to explain the observed differences. Available data are mainly drawn from studies focusing on American professional sports. The results indicate that Afro-American athletes largely dominate the sport scene in a few sports and across a wide range of performance indicators. Although it is impossible at this time to conclude with satisfaction on the causes of racial differences, sociological explanations seem best to explain the observed performance differentials.

Black People↗
PubMed1987

Experimental infections of free-ranging Rocky Mountain bighorn sheep with lungworms (Protostrongylus spp.; Nematoda: Protostrongylidae).

Twelve free-ranging Rocky Mountain bighorn lambs (Ovis canadensis canadensis), each exposed experimentally to 125-1,000 infective third-stage larvae of Protostrongylus stilesi and P. rushi, shed significantly more first-stage larvae in their feces than did control lambs, but showed no clinical signs of illness and had equivalent summer and overwinter survival as control lambs. Two adult ewes, each exposed to 925 infective larvae, showed no increase in numbers of first-stage larvae in their feces; both survived at least 14 mo postexposure. Experimentally exposed lambs did not differ from control lambs in numbers of larvae in their feces in the following summer. Three experimental lambs had 313-402 adult P. stilesi and 0-97 adult P. rushi on necropsy; two control lambs had 255 and 270 P. stilesi and no P. rushi. The presence of these numbers of lungworms did not appear to be sufficient to precipitate lungworm pneumonia in bighorn lambs under the conditions of this study.

Animals↗
PubMed1985

Induction of differentiation and inhibition of DNA methylation in HL-60 myeloid leukemic cells by 5-AZA-2'-deoxycytidine.

The effects of 5-AZA-2'-deoxycytidine (5-AZA-CdR) on the induction of morphological and biochemical differentiation and inhibition of DNA methylation of human HL-60 myeloid leukemic cells were investigated. 5-AZA-CdR at concentrations of 0.1-1 microgram ml-1 for 48-h exposure produced significant morphological differentiation of HL-60 leukemic cells to a more mature phenotype, augmented the cell surface marker (OKMI) for mature granulocytes/monocytes and also increased the superoxide anion production. Under these same conditions 5-AZA-CdR inhibited the synthesis of 5-methylcytosine in DNA suggesting that there is a correlation between the induction of differentiation and inhibition of DNA methylation. At concentrations of 5-AZA-CdR that inhibit DNA methylation there was a marked decrease in colony-formation suggesting that the antileukemic action of this analog is related to the methylation of DNA.

Antineoplastic Agents↗
PubMed1985

[Focal epithelial hyperplasia: first cases in Switzerland and review of the literature].

Three cases of 'focal epithelial hyperplasia' (FEH) of the oral mucosa observed for the first time in Switzerland are reported. The patients were of Turkish and North African extraction. The lesions of FEH were multiple, painless, located at various sites of the oral mucosa including the tongue, in the form of either soft papules or hard nodules. Evidence of a human papilloma virus origin was ascertained. Among the 1,067 cases reported in the literature and reviewed for this study, this condition has been described to occur among American Indians, Eskimos and Cape Coloureds; also in Israeli and European cases the disorder was often reported in individuals of Turkish or North African extraction.

Adult↗
PubMed1985

[Osteoblastoma of the jaws. 2 cases and a review of the literature].

The authors report on two cases of osteoblastoma: one of the maxilla in a twenty-two year old woman, the other of the mandible in a thirty-eight year old woman. In the two cases, the lesions were discovered after a systematic X-ray examination and they were treated by curettage. To date, sixty-seven cases of jawbone osteoblastoma and eleven cases of osteoid osteoma, a lesion which resembles and is perhaps similar to the osteoblastoma, have been reported in the literature. The authors develop the differential diagnosis and study the relationship between these two varieties of a same tumor or pseudo-tumor.

Adolescent↗
PubMed1979

[Early detection of pemphigus vulgaris: role of the dentist].

Means to detect pemphigus vulgaris at an early stage are described. Its grave evolution in absence of treatment makes an early diagnosis imperative. The first signs are frequently localized in the oral mucosa and sometimes the disease remains confined to this mucosa only. Efficient and early therapy may favourably influence the course of disease, and the dentist is in a prime position to detect the characteristic lesions.

Acantholysis↗
PubMedDate not supplied

[Psychogenic oral paresthesia].

Psychogenic oral paresthesia represent a proteiform condition, more and more frequent. The failure to recognize it can lead to unjustified investigations or/and procedures. These manifestations are secondary to a psychic problem which varies in severity. In most cases, the establishment of a trust relationship, explanations to the patient and eventually a psychotherapy are sufficient to eliminate the symptoms. In severe cases, a psychotherapy or a psychiatric treatment are almost always necessary.

Adult↗
PubMedDate not supplied

Corneal wound healing in monkeys 18 months after excimer laser photorefractive keratectomy.

Excimer laser keratomileusis (photorefractive keratectomy, direct corneal ablation) for myopic corrections of 2.00 diopters (n = 1), 4.00 D (n = 4), and 8.00 D (n = 3) was performed on eight corneas of four Rhesus monkeys. All animals were followed for 18 months. The ablations healed normally and no epithelial erosions occurred. Serial slit-lamp microscope examinations revealed that a variable amount of corneal haze developed in all animals; this haze progressively faded during the follow-up period. Histopathology revealed an epithelium of normal thickness, basement membrane abnormalities, increased number and activity of stromal keratocytes, and a variable amount of newly secreted extracellular matrix in the anterior stroma. These findings suggest that excimer laser keratomileusis induces a mild wound healing response in the anterior cornea which displays considerable individual variability and persists up to 18 months.

Animals↗
PubMedDate not supplied

[Chronic granulomatous disease (CGD): in vitro enhancement of bactericidal activity of CGD phagocytes by rifampicin].

In a series of 29 experiments on CGD patients, we have studied the in vitro bactericidal capacity of normal and CGD phagocytes against penicillin, streptomycin and rifampicin sensitive Staphylococcus aureus. The bactericidal activity of phagogyte preparations was tested at different intervals during a 21 hour incubation. The CGD-phagocyte bactericidy peaks after 90 min when penicillin is used; in contrast, a significant enhancement of the bactericidal activity is noted with rifampicin and best noted after 21 hours of incubation. To elucidate the mode of action of this antibiotic, a rifampicin resistant S. aureus was used in a series of experiments; The results point to a mixt type of action: antimicrobial and metabolic.

Blood Bactericidal Activity↗