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S Studer

Publications and source records attributed to S Studer.

15 recordsLinked to original sources
PubMed1989

Thymic epithelial cells induce in vitro differentiation of PRO-T lymphocyte clones into TCR alpha,beta/T3+ and TCR gamma,delta/T3+ cells.

PRO-T lymphocyte clones, which have the T cell receptor (TCR) alpha, beta, gamma and delta genes in germline configuration and heterogeneous T cell precursors freshly isolated from bone marrow of athymic nude mice, gave rise to single positive L3T4+ TCR alpha,beta+ and double negative (L3T4-LyT2-) TCR alpha,beta+ or TCR gamma,delta+ cells, but not to any cells expressing LyT2, when co-cultured with the thymic epithelial clone ET. The T cell progenitors were able to develop into cells expressing LyT2 only when cocultured with heterogeneous thymic epithelial cell preparations. The progeny of the induced PRO-T clones included cells bearing V beta 8, V beta 17 and V gamma 3 gene family products. The presence of cells expressing a TCR gamma, delta/T3 receptor complex in the cultures was also documented by the expression of RNA transcripts from the TCR delta and TCR gamma genes by induced PRO-T cells. The TCR/T3+ cells generated in the cultures expressed functionally competent T cell receptor complexes. Our results show that: (i) the same PRO-T clone can give rise to all major subsets of thymocytes upon interaction with the appropriate thymic epithelial cells; (ii) both TCR alpha,beta+ and TCR gamma,delta+ cells may originate from a common T cell progenitor; (iii) L3T4+ TCR alpha, beta+ and L3T4-LyT2- TCR alpha,beta+ cells do not necessarily pass through a L3T4+LyT2+ intermediate stage of development; and (iv) different types of thymic epithelial cells play an essential role in the differentiation of PRO-T cells into either L3T4+ TCR alpha,beta+ L3T4-LyT2- TCR alpha,beta+ or L3T4+LyT2+ and LyT2+ TCR alpha, beta+ cells in vitro. Finally, we have attempted to integrate our results and those of others in a suggested model of T cell development within the thymus.

Animals↗
PubMed1987

Short-term testosterone treatment at bone age of 12 to 13 years does not reduce adult height in boys with constitutional delay of growth and adolescence.

Growth data and adult height from 22 untreated patients with constitutional delay of growth and adolescence (group 1) were compared retrospectively with those of 19 patients, who had received long-acting testosterone esters (100 to 250 mg per month, mean total dosage 1029 mg/m2) during 2 months to 3.25 years (mean duration 8.5 months, group 2). Age (group 1 15.4 +/- 1.2, group 2 16.2 +/- 1.4 years), bone age (group 1 12.6 +/- 1.3, group 2 13.1 +/- 1.2 years) at first examination (group 1) or start of treatment (group 2), and adult height (172.8 +/- 7.5 cm group 1, 176.8 +/- 8.0 cm group 2) were not significantly different. In group 2, there was no negative correlation between the total testosterone dose and adult height, and the latter corresponded to predicted height in the same way as in the untreated patients. It is concluded that short-term treatment with long-acting testosterone esters (100 to 250 mg per month during 6 months, starting at a bone age of about 12.5 years), which has positive psychosocial effects, does not have negative somatic effects and does not reduce adult height in these patients.

Adolescent↗
PubMed1985

Evaluation of accessory cell heterogeneity. I. Differential accessory cell requirement for T helper cell activation and for T-B cooperation.

Several Ia+ tumor cell lines and peritoneal exudate macrophages were tested as accessory cells (AC) for the activation of antigen-specific T cells and for T-B cooperation. The macrophages and all the Ia+ tumor lines tested induced the release of lymphokines from T cells in a major histocompatibility complex (MHC)-restricted fashion and reconstituted the antibody responses of AC-depleted spleen cells or of purified T and B cells. However, only the normal macrophages but none of the tumor lines induced carrier-specific T helper (Th) cells which help B cells for specific antihapten antibody responses by linked recognition. For T-B cooperation accessory cells were also required, but in contrast to Th cell activation any type of Ia+ AC (e.g. macrophage or tumor line) was effective. Strong MHC-restriction between the lymphocytes and the AC was seen if antigen-pulsed AC were added into the AC-depleted T-B cooperation cultures. If the AC and antigen were concomitantly added to the AC-depleted T-B cultures, MHC-restriction was less obvious. Concanavalin A supernatant reconstituted the response of AC-depleted T-B cultures provided antigen-specific Th cells and the hapten-carrier conjugate were present. If, however, tumor line-activated T cells were added instead of macrophage-induced Th cells, no cooperation with B cells took place even in the presence of Con A supernatant. The results obtained demonstrate a differential AC requirement for the induction of Th cells depending on the differentiation stage of the Th cells.

Animals↗
PubMed1985

The lymphoproliferating cells of MRL-lpr/lpr mice are a polyclonal population that bear the T lymphocyte receptor for antigen.

Mice bearing the recessive gene lpr develop an age-dependent, massive lymphoproliferation, primarily in the lymph nodes (LN), with associated autoimmunity. LN cells from these mice express T cell receptor protein on the cell surface at 50-70% of normal levels. Normal levels of T cell receptor alpha, beta and gamma mRNA were found in these cells as compared to normal LN cells. Southern blot analysis of MRL-lpr/lpr LN DNA showed rearrangements in 80-90% of the chromosomes at the beta gene loci. The pattern of rearrangement indicated that a polyclonal rather than monoclonal expansion of T cells occurred. These data support a lymphokine-induction model of lymphoproliferation in MRL-lpr mice.

Animals↗
PubMed1984

[Metabolic effects of gliclazide in diabetes type II patients. Study with indirect calorimetry].

An attempt is made to determine the effect of treatment with gliclazide on the manner in which obese patients with noninsulin-dependent diabetes dispose of an oral glucose load. Six patients were studied on two occasions - once after one month of an isocaloric diet containing 40% carbohydrate, and two months after gliclazide had been added. Body weight remained constant throughout the three months. However, fasting plasma glucose concentration fell and mean (+/- SEM) incremental insulin response to oral glucose increased significantly (p less than 0.05) with drug therapy (51.1 +/- 14.6 microU/ml vs 17.1 +/- 1.5 microU/ml). Glucose oxidation significantly improved after gliclazide treatment (16.9 +/- 2.4 g/3 h vs 7.5 +/- 2.1 g/3 h, p less than 0.02) in parallel with the fall in plasma glucose and the increase in insulin response. In addition, glucose storage significantly increased after drug therapy (44.1 +/- 10.1 g/3 h vs 28.4 +/- 7.2 g/3 h, p less than 0.001). In contrast, lipid oxidation fell with gliclazide treatment (7.2 +/- 0.7 g/2 h vs 12.0 +/- 1.7 g/3 h, p less than 0.02). This effect may be explained by improvement of the antilipolytic effect of insulin. In conclusion, improvement in glucose oxidation (25%) and in glucose storage (55%), together with reduced lipid oxidation, was observed after two months of gliclazide therapy.

Blood Glucose↗
PubMed1983

Evaluation of Ia+ tumor cell lines and peritoneal exudate macrophages as accessory cells: differential requirements for the activation of certain T cell functions.

Several Ia+ (BC3A, TA3, D1B) or Ia-inducible (WEHI-3, P388D1) tumor lines were tested for accessory cell function for the activation of antigen-specific T cell proliferation and for the induction of T helper cells that help B cells in antibody production. All lines were able to induce antigen-specific T cell proliferation in an MHC-restricted way, but none activated T helper cells to soluble antigens under all conditions tested. In comparison, starch-induced peritoneal exudate macrophages induced T cell proliferation as well as T cell help. Some of the lines tested induced nonspecific suppressor cells that were Ly-2-positive and partially or completely inhibited antibody responses. The induction of suppressor cells, however, is not the reason for the failure of the tumor lines to activate T helper cells. These data indicate that antigen-specific T cell proliferation and helper activity do not necessarily correlate.

Animals↗
PubMed1980

Characterization of accessory cells required for helper T cell induction in vitro: evidence for a phagocytic, Fc-receptor, and Ia-bearing cell type.

The nature of the accessory cell type required for the in vitro induction of antigen-specific helper T (Th) cells to soluble antigen was determined. Two different sources of adherent accessory cells were investigated: peritoneal exudate cells (PEC) and macrophages derived from bone-marrow cells (BMM phi), which were cultured for 8 days in vitro with colony-stimulating factor. PEC and BMM phi were rosetted with EA-SRBC and separated by sedimentation into Fc gamma receptor-positive and negative fractions. Only the Fc gamma receptor-positive fraction was active in Th-cell induction. By means of the fluorescence-activated-cell sorter (FACS-II), PEC or BMM phi were separated either into phagocytic and nonphagocytic, or Ia-positive and Ia-negative cell populations. Only phagocytic and Ia-positive accessory cells induced antigen specific Th cells. In conclusion, the accessory cell is adherent, phagocytic, carries Fc gamma-receptors and Ia products, and thus expresses the most important characteristics of the macrophage lineage.

Animals↗
PubMed1979

The treatment of atrophic vaginal conditions with Ortho-Gynest: a pilot study.

A clinical study was undertaken, in twenty-four patients with atrophic vaginal changes, to assess the efficacy and the acceptability of treatment with Ortho-Gynesi vaginal suppositories, which have as their active constituent the naturally occurring substance oestriol. A regenerative effect on the vaginal epithelium could be objectively demonstrated by an increase in the proportion of superficial cells following treatment. Changes in the vaginal epithelium were accompanied by a diminution in the incidence of infection and inflammation. Subjective complaints such as dyspareunia, pruritus and kraurosis vulvae, which could also be ascribed to a relative oestrogen deficiency, responded well to treatment.

Aged↗
PubMedDate not supplied

Maxillary anterior single-tooth replacement: comparison of three treatment modalities.

The correct treatment of a single missing maxillary anterior tooth in the aesthetically prominent area has become more challenging. The missing tooth can today be replaced by one of three prosthodontic treatment modalities--conventional fixed bridge, resin-bonded bridge, and single-tooth implant. The most important factors to be considered are the predictability of aesthetics, the preservation of the enamel shield and the dentinal and pulpal tissue, and the preservation of the periodontium and the alveolar bone. The learning objective of this article is a critical discussion of these three modalities as a replacement of a missing anterior single tooth to aid in selection of the most appropriate treatment in each individual clinical case.

Dental Implants↗