PubMed Health⌕ Search

Biomedical subjects

K Schroder

Publications and source records attributed to K Schroder.

11 recordsLinked to original sources
PubMed1994

Rat T cell responses to superantigens. II. Allelic differences in V beta 8.2 and V beta 8.5 beta chains determine responsiveness to staphylococcal enterotoxin B and mouse mammary tumor virus-encoded products.

The previous paper in this series demonstrates that rat T cells developing de novo in the presence of mouse mammary tumor virus (Mtv) antigens in rat-->severe combined immunodeficiency (SCID) mouse xenochimeras display a distinct pattern of V beta-restricted deletion; this deletion pattern is remarkably similar to that occurring during thymic development of mouse T cells in Mtv+ strains. In addition, T cells developing in the absence of Mtv antigens in these rat-->mouse xenochimeras are tolerant of host antigens, but show strong primary proliferative responses in cultures stimulated with Mtv-7+ (Mlsa) mouse cells; like the mouse, these rat T cell responses are dominated by V beta 6 and V beta 8 T cells. Here, we continue analysis of rat T cell responses to superantigens; we show that T cells from Lewis and Fischer 344 rats expressing V beta 8.2 display an important all-or-nothing difference in their responses to Mtv-7 superantigens. This all-or-none strain difference in the response to Mtv-7 applies also to the response by V beta 8.2 and V beta 8.5 T cells to the soluble superantigen staphylococcal enterotoxin B. Because these two rat strains express different alleles of these two V beta 8 family members, this finding identifies additional, hitherto unreported residues of the T cell receptor beta chain important in T cell responses to superantigens.

Alleles↗
PubMed1986

Cyclosporine-induced autoimmunity. Conditions for expressing disease, requirement for intact thymus, and potency estimates of autoimmune lymphocytes in drug-treated rats.

These studies explore the phenomenon of cyclosporine-induced autoimmunity in irradiated Lewis rats. We show that (a) the presence of a thymus is required, and autoimmune precursors develop in and exit from this organ to the peripheral lymphocyte pool within a 2-wk period after the initiation of cyclosporine treatment; (b) adoptive transfers of drug-induced autoimmunity to irradiated secondary recipients can be accomplished with relatively few cells of the Th subset, and these transfers of autoimmunity can be blocked by cotransfer of normal lymphoid cells; and (c) potency estimates, using popliteal lymph node assays in syngeneic and F1 recipients indicate similar levels of auto- and alloreactivity by cells from drug-induced autoimmune donors. These various findings indicate that this particular animal model may be useful for studies of the onset and control of autoimmunity, and they raise the possibility that the lack of autoimmunity in normal animals and its induction with cyclosporine may involve similar cellular mechanism as have been found to be operative in GVH reactions and specifically induced immunologic resistance to GVHD.

Animals↗
PubMed1984

Historical antecedents of dental anxiety.

Our data are based on retrospective self-reported answers of college students. To what extent do these answers accurately reflect the feelings of an actual clinical sample of dental patients? Although there is little direct evidence, a number of observations suggest that in the area of dental anxiety, college populations closely approximate the self-reported answers of the general population. The average level of dental anxiety in an actual clinical sample also appears to be remarkably similar to the average level of dental anxiety among a sample of college students. Kleinknecht and Bernstein found that, on a 1 to 5 scale, dental patients reported a mean level of dental anxiety of 2.31, and that when the identical question was used in a college population, the average level of dental anxiety was 2.47. In our sample, the mean level of dental anxiety was a similar 2.4 on a 0 to 6 scale. Obviously, self-reported answers are subject to distortions. However, it is important that these perceptions can still have a powerful bearing on the behaviors and feelings of patients. A number of observations and hypotheses about the historical origins of dental anxiety were confirmed. Some of these findings have direct clinical implications for the prevention of dental anxiety by dentists or treatment by psychologists. For example, high dentally anxious subjects are more concerned with and feel more ashamed about telling their dentist that they are dentally anxious. It may be helpful for dentists to provide an open forum about the patient's concern.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Oral administration of alpha-ketoisovaleric acid or valine in humans: blood kinetics and biochemical effects.

alpha-Ketoisovaleric acid levels increase from 10.6 +/- 0.8 to 121 +/- 20 mumol/L, and valine levels increase from 175 +/- 14 to 940 +/- 50 mumol/L after oral administration of an isomolar (62.5 mg/kg) bolus of alpha-ketoisovaleric acid or valine to healthy human subjects. alpha-Ketoisovaleric acid levels have a different time course relative to valine. alpha-Ketoisovaleric acid and valine affect various other amino and keto acids, and some of these effects are qualitatively different. alpha-Ketoisovaleric acid enhances alpha-ketoisocaproic acid and alpha-keto-beta-methyl-n-valeric acid, but diminishes the corresponding amino acids, and causes an early decline of ornithine along with a late augmentation of plasma arginine. Valine does the opposite. The data suggest that in humans, overall capacity for alpha-ketoisovaleric acid decarboxylation appears greater than the capacity for valine transamination, and that all branched-chain amino acids and branched-chain keto acids seem to be interconvertible by reversible transaminations.

Administration, Oral↗
PubMed1980

Circumcision, gender differences, and neonatal behavior: an update.

As a test of the hypothesis that gender differences in neonatal behavior may be linked to circumcision, we reviewed 38 recent studies which provide relevant information. No strong data exist to support the hypothesis or to document the existence of gender differences in neonatal behavior.

Child Behavior↗
PubMed1976

Anaesthesia for cystoscopy. A comparative study of 3 methods of intravenous anaesthesia: diazepam-fentanyl, thiomebumal and althesin.

Three different methods of anaesthesia for diagnostic cystoscopy are compared in randomly divided series of 100 males each. Group I received diazepam-fentanyl supplemented with Althesin in case of therapeutic transurethral procedures. Group II had thiomebumalnatrium-N2O-O2 and group III had althesin-N2O-O2. Group I had no premedication while the two others were premedicated with morphine-scopolamine mixture. The period during and after anaesthesia was observed independently by the urologist, the anaesthetist, the nurses on the ward and by interviewing the patient the day after the cystoscopy. The anaesthetist was the only one who knew the method to be used. Diazepam-fentanyl proved to give sufficient analgesia. This combination offered the shortest and most uncomplicated period of recovery. Five patients given diazepam-fentanyl remembered the cystoscopy as being painful. All these cases could be related to insufficient coordination of anaesthesia and cystoscopy, which seems to be of major importance for this method.

Aged↗
PubMed1975

DNA synthesis in HeLa cell nuclei isolated in a non-aqueous medium.

Nuclei were isolated from synchronized HeLa cells in the S-phase by a modification of the non-aqueous method described by Kirsch et al. (Science (1970) 168, 1592-1595). The method involved lyophilization of the cells, homogenization in non-aqueous glycerol and centrifugation in a gradient of 0-35% (w/w) 3-chloro-1,2-propanediol in glycerol. Such nucleic incorporated deoxyribonucleotides into DNA when incubated in an aqueous buffer containing Mg2+, ATP, dATP, dGTP, dCTP and dTTP. The product was sensitive to DNAase and banded with bulk DNA in isopycnic centrifugation. Sedimentation of the product in alkaline sucrose gradients after labelling of the nuclei for 2 min revealed labelled material in the 5 S peak and in the 18 S area. The material in the 5 S peak moved into the 12 S area after a 13 min chase.

Cell Fractionation↗