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Biomedical subjects

D W Scott

Publications and source records attributed to D W Scott.

At least 253 records · Page 14Linked to original sources
PubMed1977

The induction of carrier-specific helper cell tolerance in presensitized rats.

Lewis rats rendered tolerant to sheep IgG (SGG) show a markedly reduced antibody response to the 2,4,6-trinitrophenyl (TNP) hapten when later challenged with TNP-SGG. We have previously shown that this effect is due to functional unresponsiveness in the carrier SGG-specific helper T cell population. In this paper we demonstrate that induced helper cell tolerance is also maintained through a secondary immunogenic challenge. Furthermore, rats which are primed to the carrier SGG prior to tolerance induction also show a markedly reduced anti-TNP response upon secondary immunogenic challenge with TNP-SGG. The ability to specifically suppress a secondary response in this manner was found to be relatively long lasting, since rats showed reduced responsiveness when the secondary challenge was delayed for up to 4 weeks after tolerance induction. In addition, rats primed to the hapten (TNP) prior to carrier (SGG) tolerance induction also showed a marked reduction in anti-TNP antibody following challenge with TNP-SGG. These findings imply that helper cell tolerance can be induced in rats even after priming of carrier-specific (SGG) helper cells, or hapten-specific (TNP) B cells. These results parallel our other published findings that IgE responses in presensitized rats can be overcome by helper cell tolerance.

Animals↗
PubMed1977

Factors affecting the choice of hospital-based ambulatory care by the urban poor.

This study of patients in the outpatient department at an urban hospital revealed that almost all could have reached a neighborhood center in less time and only a small number came to the hospital rather than a neighborhood center out of medical necessity. When the patients were asked about their willingness to obtain treatment at a neighborhood center, 48 per cent were willing, 52 per cent were not. These responses did not vary by demographic or medical characteristics but rather by the patients' stated priorities regarding medical care. Eighty per cent of those willing to change sites stressed convenience of access as a first priority compared with only 17 per ccent of those not willing to change. Emphasis on quality of care (45 per cent) or on familarity with the site (37 per cent) distinguished the group not willing to change. The findings suggest that successful efforts to persuade patients to utilize a neighborhood center must base their appeal on patients' individual priorities.

Ambulatory Care↗
PubMed1977

Laminar avulsion in a cervical vertebra.

An unusual avulsion fracture involving the lamina of a cervical vertebra, most likely due to tear of a ligamentum flavum, is described. Its radiographic features may be quite subtle. Simulation of this fracture on dried skeleton allowed a better understanding of its appearance on the standard projections, its mechanism of occurrence, and its delayed recognition on the patient's anteroposterior view. Only awareness of the existence of this type of fracture and special efforts directed toward its detection will determine its true frequency.

Adolescent↗
PubMed1977

Cellular events in tolerance. VI. Neonatal vs adult B cell tolerance: differences in antigen-binding cell patterns and lipopolysaccharide stimulation.

The numbers and fate of antigen-binding cells (ABC) in neonatal and adult mice rendered tolerant to fluorescein (FL)-labeled heterologous gamma-globulins were studied. Similar numbers of FL-ABC were observed 1 day after tolerogen in both adult and neonatal mouse spleens: by 7 days after tolerization, no FL-ABC were observed in either case. Reinjection with FL-tolerogen at 7 days led to the detection of normal numbers of ABC in adult mice but significantly reduced numbers in neonates. This suggests that neonatal ABC either have been deleted or have failed to resynthesize surface receptors. Two weeks after tolerance induction, spleen cells from these tolerant mice were cultured with Escherichia coli lipopolysaccharide (LPS), a polyclonal B cell mitogen, or with specific antigen. Tolerant adult spleen cells made an equivalent anti-FL response to that of the uninjected controls when stimulated with LPS, but were unresponsive to specific antigenic triggering. In contrast, spleen cells from neonatally tolerized mice were unresponsive to either specific or nonspecific (LPS) stimulation. Thus, these neonatally tolerized spleen cells lose sensitivity to polyclonal-stimulating agents (along with their receptors), or more simply, are deleted.

Aging↗
PubMed1977

Cost-effectiveness of cardiopulmonary resuscitation training programs.

A model is presented to analyze the cost-effectiveness of programs to train large numbers of citizens in the techniques of cardiopulmonary resuscitation (CPR). From a planner's estimates of certain key factors, the model determines the probability of intervention for various numbers of trained citizens and for several allocation strategies and patterns of population density. These key factors are the maximum distance from which a person with CPR training could intervene in an emergency, the cost of training, and loss of skill with time. The model is used to analyze possible training efforts in Houston, Texas.

Cost-Benefit Analysis↗
PubMed1977

Pemphigus vegetans in a dog.

Pemphigus vegetans of the Hallopeau type was diagnosed in aged dog. Diagnosis was based on (a) history, (b) physical examination, (c) histopathologic examination of affected skin, and (d) response to therapy. Clinical response to immunosuppressive doses of prednisolone was excellent.

Animals↗
PubMed1976

Role of self-carriers in the immune response and tolerance. I. B-cell unresponsiveness and cytotoxic T-cell immunity induced by haptenated syngeneic lymphoid cells.

Normal spleen cells cultured with TNP-modified syngeneic spleen cells fail to mount an anti-TNP PFC response to TNP-ficoll or TNP-red blood cells,but go on to generate cytotoxic T cells directed at hapten-modified H-2.These results suggest that hapten-modifeid spleen cells may differentially induce B-cell tolerance and T- (Ly 2,3) cell immunity. The differential response to modified self by lymphocyte subpopulations is discussed.

Animals↗
PubMed1976

Antifluorescein affinity columns. Isolation and immunocompetence of lymphocytes that bind fluoresceinated antigens in vivo or in vitro.

A new method for the isolation of specific immunocompetent lymphocytes has been described in which lymphocyte populations are exposed to fluoresceinated antigens (FLAGs) in vivo or in vitro, and the FLAG-binding cells retained on antifluorescein affinity columns. Specific cells are then eluted with an unrelated FL-labeled protein and shown to be fully immunocompetent. This methodology has been applied successfully in diverse antigenic systems including polymerized flagellin and TNP-specific B cells and alloantigen-reactive cytotoxic T lymphocytes. The method is rapid, inexpensive (requiring only antifluorescein beads), and can be applied to any antigens (or antibodies) in which a fluorescein group can be introduced.

Animals↗
PubMed1976

Drug eruption associated with sulfonamide treatment of vertebral osteomyelitis in a dog.

Drug eruption was diagnosed in a 4-year-old German Shepherd Dog being treated with sulfonamides for vertebral osteomyelitis due to infection with Nocardia spp. The eruption was characterized by generalized, pruritic, eczematous dermatitis. Diagnosis was based on a history of repeated exposure to sulfonamides, skin biopsy findingd, and clinical recovery on cessation of sulfonamide therapy.

Animals↗