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Biomedical subjects

S C Schneider

Publications and source records attributed to S C Schneider.

7 recordsLinked to original sources
PubMed1997

Antigen processing differences among APC.

The hierarchy of display of determinants on a protein antigen is of critical importance with respect to which T cells will be selected during thymic development, as well as in the induction of mature responses. Activation of T cells will be dependent on unfolding, reduction and chain cleavage of the antigen, and the vagaries of competition with other determinants as well as hindrance in access to the major histocompatibility complex (MHC) or subsequently of the MHC/peptide complex to the T cell receptor. We here focus on a description of the parameters that determine the generation and display of determinants on MHC class II molecules by different types of antigen presenting cells in different locations.

Antigen Presentation↗
PubMed1997

Attention-deficit hyperactivity disorder. In pursuit of diagnostic accuracy.

Attention-deficit behaviors create a substantial burden for healthcare facilities. The incidence of ADHD is estimated at 5% to 10% of school-age children, but it is possible that many diagnoses of ADHD are flawed. At present, because the etiology of the disorder is not well understood, the diagnosis of ADHD by DSM-IV criteria hinges on the presence of inattention, hyperactivity, impulsivity, or a combination of these. Children who do not have ADHD also exhibit such behaviors in certain environments, as do children with learning disorders, family relational problems, and emotional difficulties. Thus it is imperative that physicians take a comprehensive approach to diagnosis when a child presents with behavioral difficulties. Noting that a number of myths about ADHD (eg, that improved behavior after being given stimulant medication proves a diagnosis of ADHD) have recently gained currency, the authors recommend going beyond the first step of behavior checklists in diagnosing the disorder and describe situations in which further assessment is indicated.

Attention Deficit Disorder with Hyperactivity↗
PubMed1997

Attention-deficit hyperactivity disorder. Pharmacotherapy and beyond.

Management of ADHD is a challenge that requires time, commitment, and great sensitivity on the part of the physician. Use of stimulant medications is often successful at improving symptoms, but it has become the knee-jerk treatment response for many. Given the wide-ranging effects of ADHD on aspects of patients' lives and the availability of various treatment alternatives, a multimodal approach is considered optimal. As more studies evaluate nonpharmacologic approaches such as behavior therapy, parent education, and neurofeedback and more physicians implement multimodal treatment, outcomes for patients with ADHD are expected to be even more positive.

Antidepressive Agents, Tricyclic↗
PubMed1995

Self-reactive T cell hybridomas and tolerance. Same range of antigen dose dependence but higher numbers of self-reactive T cell hybridomas from mice in which self-tolerance has been broken by antiserum treatment.

Mechanisms of self-tolerance of 4-hydroxyphenylpyruvate dioxygenase (HPPD) are explored. It is well established that negative selection based on TCR affinity occurs in the thymus. We have investigated the frequency with which self-reactive T cell hybridomas can be obtained in relation to self-tolerance. Mice immunized with the self-form of HPPD gave rise to T cell hybridomas that were able to recognize self-protein and a synthetic peptide representing the T cell epitope, at higher Ag concentration than was necessary for recognition of allo-protein. The efficiency of negative selection was then reduced by treating neonatal mice with anti-HPPD antiserum. This reduced T cell tolerance of the self-protein, as judged by in vitro proliferation, and enabled self-reactive T cell hybridomas to be generated at a higher frequency. However, the Ag concentration requirements of these hybridomas for the self-protein and the self-peptide remained unaltered. The possibility that these findings reflect an auxiliary mechanism of self-tolerance based on frequencies of self-reactive T cells is discussed.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1994

Primed lymphocytes are boosted by type II collagen of their hosts after adoptive transfer.

A central question in understanding autoimmunity is whether an endogenous self-antigen can drive an immune response initially triggered by a foreign one. This possibility is here tested by adoptive transfer, in which T and B cells from mice primed with foreign type II collagen were transferred into irradiated syngeneic hosts. Previous work with other protein antigens has established that primed cells normally respond only if boosted after transfer with antigen. In the present case, and in respect only to that portion of the antibody response able to bind to endogenous type II collagen, that requirement did not hold. This indicates that the anti-self component is indeed driven by endogenous antigen, which the transferred lymphocytes presumably obtain from their adoptive hosts. The transfers were carried out in C57BL10.A x DBA/1 mice using donors primed with either chick or bovine collagen, and the non-boosted responses, presumably driven by endogenous antigen, could be followed in a proportion of the recipients for as long as 45 days.

Animals↗