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Biomedical subjects

J Samson

Publications and source records attributed to J Samson.

At least 19 recordsLinked to original sources

Human odontoblasts contain S-100 protein-like immunoreactivity.

S-100 protein is a group of three closely related isoforms (S-100ao, S-100a, and S-100b). This protein was first described as unique to the nervous system but it has also been identified subsequently in a variety of cell types of neuroectodermal (i.e., melanocytes, glial cells) and non-neuroectodermal origin (i.e., Langerhans cells, adipocytes, chondrocytes). In the present investigation the presence of S-100 protein was studied in human odontoblasts using a specific polyclonal antibody directed against S-100 protein in immunoperoxidase labelling experiments. The S-100 protein was detected in the cytoplasm of odontoblasts. This result suggests that S-100 protein can play a role in odontoblast functions.

Antibodies

Expression of intermediate filaments and actins in human dental pulp and embryonic dental papilla.

The localization of different cytoskeletal proteins (keratin, vimentin, desmin, actin, and alpha-smooth muscle actin) was examined by immunohistochemistry in normal human adult dental pulp and compared with dental papilla of tooth germs. Keratin and actin were localized in enamel organ. Vimentin and actin were observed in the dental papilla and in the adult dental pulp. Desmin and alpha-smooth muscle actin were present only in the vessel walls. These data are discussed paying particular attention to the origin and the peculiar functional characters of the dental papilla and pulp.

Actins

Comparative immunohistochemical analysis between jaw myxoma and mesenchymal cells of tooth germ.

The histogenesis of jaw myxoma is still debated. According to some authors it arises from the primitive mesenchymal components of developing teeth. In this study, we have studied the expression of S-100 protein and vimentin in dental follicle, dental papilla and periodontal ligament cells using monoclonal and polyclonal antibodies. Myxoma of the jaw expresses vimentin and S-100 protein. On the contrary, as compared to jaw myxoma, the normal developmental structures were immunonegative for S-100 protein but stained for vimentin. These results could indicate a difference in the derivation other than tooth mesenchyma.

Biomarkers, Tumor

Diagnosis of vertical HIV-1 transmission using the polymerase chain reaction and dried blood spot specimens.

We have used the polymerase chain reaction (PCR) to detect HIV proviral sequences in minute amounts of peripheral blood collected onto newborn screening blotters. Forty-three newborns, infants, and children of HIV-infected mothers were serially studied: dried blood spot (DBS) specimens were processed for PCR; serum was assayed for HIV antibodies, p24 antigen, and immunoglobulins; mononuclear cells were cultured and CD4 cells were quantitated by immunofluorescence. There was excellent agreement between the results of blood spot PCR, viral culture, and clinical and immunological indicators of HIV infection. Eighteen of 19 infected children tested positive by both PCR and culture, including six asymptomatic infants who were less than 10 weeks of age. As expected, p24 antigen capture assays were insensitive, detecting only 13 of the 19 infected children. One infected infant tested positive by PCR, but negative by culture and antigen. This infant was seropositive at 27 months and had pronounced hypergammaglobulinemia in association with non-specific symptoms. Twenty-four of the 43 infants were asymptomatic with normal immune profiles, declining antibody levels and no evidence of infection. These children tested repeatedly negative by PCR, culture, and p24 antigen assays. Our results indicate that DBS PCR is a sensitive, specific, and cost-effective alternative to viral culture for the early diagnosis (or exclusion) of perinatal HIV infection. DBS sampling opens the way for large-scale prospective studies to determine the exact rates of vertical HIV transmission in industrialized, as well as, nonindustrialized countries.

Child, Preschool

[Lichen planus. Clinical diagnosis, epidemiology and pathogenesis].

Lichen planus is a common mucocutaneous disease of unknown etiology which was initially described a century ago. The specific etiology remains unclear. A number of relationships between lichen planus and other conditions have been noted. The lesions occur most commonly on the buccal mucosa. Gingival involvement occurs in approximately 10% of reported cases. The appearance of lichen planus is extremely variable which leads to confusion with other clinically similar disease entities.

Adult

[Focal epithelial hyperplasia].

Five cases of "focal epithelial hyperplasia" (FEH) of the oral mucosa observed 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 1067 cases reported in the literature and reviewed for this study, this condition has been described to occur among American Indians, Eskimos and North African, also in Israeli and European cases the disorder was often reported in individuals of Turkish or North African extraction.

Adult

[Myxoma of the jaws].

A review of the literature and two observations made by the Authors regarding maxillary myxoma allow a closer analysis to be made of this rare benign tumour which is, however, often recurrent in young adults. Maxillary myxoma is identified by the appearance of a non-inflammatory and often painless swelling which, in radiological terms, appears to have a zone of multilocular and sometimes unilocular osteolysis. In histological terms, this globular whitish-greyish gelatine-like tumour is made up of an abundant stroma which encloses star-shaped or fusiform cells and rare collagen fibres. Treatment should be conservative where possible since radical surgery does not preclude recurrence; follow-up should be regular and long in order to ensure an early diagnosis of recividation. Although it is considered an odontogenic tumour, the odontogenic nature of maxillary myxoma has not been undisputably ascertained. The term maxillary myxoma is therefore preferable to that of odontogenic myxoma.

Adult

Field immobilization of bighorn sheep with xylazine hydrochloride and antagonism with idazoxan.

Xylazine hydrochloride was used to immobilize 124 Rocky Mountain bighorn sheep (Ovis canadensis canadensis) between 1983 and 1988. Doses of xylazine for free-ranging lambs ranged from 70 to 130 mg with amounts increasing with lamb age. Average doses for 11 free-ranging adult males and 21 adult females darted from the ground were (means +/- SE) 363 +/- 16 and 251 +/- 7 mg, respectively. Adult females captured in "Stevenson's " box traps (n = 7) could be immobilized with significantly (P less than 0.001) less xylazine (93 +/- 9 mg) than free-ranging females but had similar induction times. Long recovery times associated with xylazine immobilization were eliminated with the intravenous administration of idazoxan (RX 781094) at an approximate dosage of 0.1 mg/kg. Eighteen sheep given idazoxan appeared fully recovered within 3 min of injection (means +/- SE = 1.2 +/- 0.2 min). Four mortalities (three lambs, one yearling male) (3% of total) occurred before idazoxan was available for trial.

Adrenergic alpha-Antagonists

[Oral candidiasis: epidemiology, diagnosis and treatment].

Oral candidiasis, an opportunistic infection increasingly often met, includes many clinical aspects where oral thrush is the best known. The etiology is often iatrogenic but candidiasis also represents the most frequent opportunistic infection in HIV infection. To avoid recurrences, therapy must begin with elimination of factors which have promoted its development. Imidazoles appear to furnish the most effective antifungal therapy.

Antifungal Agents

[Intramandibular inclusions of salivary gland tissue].

Salivary gland tissue inclusions in the mandible appear as well delimited radiolucency areas, asymptomatic, usually located in the mandibular angle and sometimes in the premolar canine and symphysis regions. The examination of 8,500 radiographs has demonstrated an incidence of one radiolucent area at the mandibular angle every 500 radiographs. Our result is slightly inferior to the mean reported in the literature. Seven cases were examined. Six of them have been treated surgically and histologically. At exploration a defect in the lingual cortical plate was found. The cavities were filled by salivary gland tissue. The contents of the cavities were attached via the lingual cortical defect to the near salivary gland. The cause of such radiolucency situated in the mandibular angle seems to be an altered resorption and apposition process of the bone triggered by a modification of the salivary glands elasticity; on the contrary, the salivary inclusions in the symphysis region is referred to as embryonic origin. In the literature different terms are used often in relation with a pathogenetical hypothesis; in this paper we suggest rather a description terminology such as intramandibular salivary tissue.

Adult

Canthaxanthin retinopathy. Anatomic and functional reversibility.

Canthaxanthin intake is associated with golden yellow crystalline deposits in the retina around the macula and low static luminance threshold. Our study assesses the anatomic and functional reversibility of canthaxanthin retinopathy. The number of retinal deposits was evaluated in nine patients, two to four times over a mean period of 55 months. There was no significant difference after a nine-month follow-up. A statistically significant decrease in the number of retinal deposits was found after an observation period of 26 months. The deposits disappeared slowly, while some remained even seven years after canthaxanthin therapy was discontinued. Threshold static perimetry performed on eight patients with retinopathy and seven controls did not differ significantly between the two groups at the end of the follow-up period. The results demonstrate that canthaxanthin retinopathy is reversible.

Adult

Scanning slit delivery system.

We describe the structure and function of a delivery system designed for use with an argon fluoride excimer laser for corneal surgery. The basic principle of the delivery system is to shape the laser beam with a slit mask to a defined configuration. The image of the slit is moved across the cornea in a mathematically defined pattern to ablate a given amount of tissue, creating a new anterior radius of curvature for the cornea. The location of the beam on the cornea is determined by a rotating dove prism and a translating spherical lens, each of which is controlled by computer-regulated servomotors. The system is versatile and can be used for laser myopic or hyperopic keratomileusis, for correction of astigmatism by surface ablation, for creation of radial or transverse linear cuts, for excision of corneal buttons, and for uniform lamellar corneal smoothing procedures. The delivery system is currently used in the laboratory for the ablation of nonhuman primate corneas.

Animals

Static perimetry in canthaxanthin maculopathy.

We performed threshold static perimetry on 19 patients who had ingested canthaxanthin; 11 had maculopathy and eight did not. Patients with no history of canthaxanthin ingestion served as controls. All patients had visual acuity of 6/9 or better. Threshold static perimetry was reevaluated two to three years after cessation of canthaxanthin ingestion. For both testing sessions, patients with maculopathy presented lower retinal sensitivity than controls, while patients without maculopathy did not differ significantly from the control group. These results suggest that canthaxanthin retinopathy can adversely affect the neurosensory retina.

Adult

Immunohistochemical staining for vimentin filaments and S-100 protein in myxoma of the jaws.

Two jaw myxomas have been analyzed by a panel of antibodies to characterize this tumour type. Vimentin, but not keratin, neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), neurofilament (NF), desmin and Factor VIII-related antigen (FVIII-AG), demonstrated positivity in the cytoplasm of the neoplastic cells. Moreover, an antibody against S-100 protein also showed a strong positive reaction in the cytoplasm of the tumour cells examined. Thus directly indicating a mesenchymal derivation for odontogenic myxoma, and is the first demonstration of S-100 protein within the cells of this tumour type.

Adult