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Biomedical subjects

D Baker

Publications and source records attributed to D Baker.

At least 37 records · Page 2Linked to original sources
PubMed1991

Contextual variations in the meaning of health inequality.

The meaning of inequality in health is contextually determined; it changes both within and between countries and over time. This paper points to the limited ability of the classic class-based analyses of inequalities in health to explain such change. An alternative form of analysis, based on the interaction between age, gender and cause of death is proposed. Within this framework, intercountry (European) comparisons of life expectancy and age-specific mortality for both sexes are used to illustrate a shift over time in the social aetiology of disease from economic to behaviourally based causality. Implications for the British experience and for British social policy are discussed.

Cause of Death↗
PubMed1991

Evaluation of drug information for cardiology patients.

1. Cardiologists and pharmacists at the University Hospital of Wales collaborated to write 20 individual leaflets incorporating guidelines for a range of drugs used in the treatment of cardiology patients. The Plain English Campaign advised on the intelligibility and presentation of the information. 2. One hundred and twenty-five patients from the Regional Cardiology Unit, University Hospital of Wales were randomly allocated to receive usual verbal counselling about their drug treatment with or without an individualised drug information wallet. Two weeks after discharge from hospital patients completed a postal questionnaire to determine their satisfaction with the information about their drug treatment and their understanding of it. Forty-nine questionnaires were returned from the leaflet group and 52 from the control group. 3. The provision of written guidelines resulted in significant improvements in patients' satisfaction with their drug treatment (chi 2 = 33.3, P less than 0.001) and their understanding of it (P less than 0.001, Mann-Whitney test). Overall, patients who received leaflets were more likely to be aware of the potential side effects of their drugs but less likely to be apprehensive about them. Succinct guidelines concerning drug therapy can be assimilated by cardiology patients and provide them with a permanent record for future reference.

Adult↗
PubMed1991

Selective impairment of T lymphocyte activation following contact sensitization with oxazolone.

We have previously reported that topical exposure of mice to oxazolone results in the appearance of regulatory mechanisms which markedly depress lymph node cell (LNC) proliferative responses to subsequent challenge with the same chemical. In the present study, we have sought to identify the cellular targets for such immunoregulation. Autoradiographic analyses revealed that although pre-exposure to oxazolone caused a substantial reduction of paracortical hyperplasia following challenge, the frequency of proliferating cells in lymphoid follicles was slightly increased. That B lymphocyte responses are unaffected by oxazolone-induced immunoregulation was confirmed by investigation of anti-hapten antibody formation by draining LNC. Challenge with oxazolone resulted in an accelerated antibody response in mice previously exposed to the same chemical. These data reveal that the active immunoregulation induced following sensitization with oxazolone is selective for T lymphocytes. Evidence is presented that CD4+ and CD8+ T lymphocytes possess equivalent sensitivity to these mechanisms.

Administration, Topical↗
PubMed1991

Expression of vascular addressins and ICAM-1 by endothelial cells in the spinal cord during chronic relapsing experimental allergic encephalomyelitis in the Biozzi AB/H mouse.

The expression of adhesion molecules on central nervous system (CNS) endothelia was examined during chronic relapsing experimental allergic encephalomyelitis (CREAE) in the Biozzi AB/H mouse. Active disease episodes (acute and relapse) were associated with the up-regulation of MALA-2, the murine homologue of intercellular adhesion molecule-1 (ICAM-1), on CNS endothelia and the infiltration of ICAM-1-positive mononuclear cells. In addition, the high endothelial venule (HEV)-associated MECA-325 antigen was evident in perivascular lesions, particularly in relapsing disease. The peripheral lymph node HEV-associated vascular addressin defined by MECA-79 antibody was not detectable in the CNS during CREAE. However, the mucosal HEV addressin was evident in lesions, which ultrastructurally was found to be expressed on the surface of endothelial cells by immunoelectron microscopy. The expression of adhesion molecules, such as ICAM-1, may provide a means by which both the initial neuroantigen-specific and the subsequent antigen-non specific cells extravasate into the CNS. Such infiltration may induce the expression of the vascular addressins which may then provide a means of site-selective cellular recruitment leading to disease progression.

Animals↗
PubMed1991

Antigen-specific and non-specific depression of proliferative responses induced during contact sensitivity in mice.

Exposure of the flank of mice to either oxazolone or trinitrochlorobenzene (TNCB) 5 days prior to the application of oxazolone on the ear resulted in a reduced capacity of oxazolone-induced draining lymph node cells to express IL-2 receptors, produce IL-2, protein, RNA and DNA. However, histological examination of the draining lymph node suggest that antigen-specific and antigen-non-specific influences differ with respect to the frequency of pyroninophilic cells. Pre-exposure to oxazolone suppressed the number of oxazolone-induced pyroninophilic T cell blasts, whereas draining lymph nodes from TNCB-pretreated mice contained significantly more pyroninophilic cells than from oxazolone-pretreated mice. However, the majority of these cells were incorporating little or no thymidine. Thus exposure to certain contact sensitizers induces at least two systemic control mechanisms which serve to regulate subsequent lymphoproliferative responses. These mechanisms appear to exert their influences at different stages of in-vivo T cell activation.

Animals↗
PubMed1990

Structure, cellular distribution, and functional characteristics of the guinea pig leucocyte common antigen.

The guinea pig leucocyte common antigen (LCA), expressed on different hemopoietic cells, was examined using the monoclonal antibody (mAb) H 201. Immunohistology and FACS analysis revealed that T and B lymphocytes, macrophages, and thymocytes express the H 201 epitope in comparable density. The level of LCA-expression increased during the course of maturation and activation of T cells. Differences in the molecular weight of LCA were observed, which depended on the nature of various cell populations, indicating that in each case alternative variants of LCA are expressed. The molecular weight of guinea pig LCA ranged from 175 kDa on thymocytes, up to a 230-kDa variant found on B lymphocytes. Antigen- or alloantigen-induced T cell activation in vitro was moderately affected by the continuous presence of mAb 201. In contrast, the PHA-mediated T cell proliferation was strongly and selectively enhanced, supporting the assumption of an LCA involvement in the "alternative pathway" of T cell activation.

Animals↗
PubMed1990

Induction of chronic relapsing experimental allergic encephalomyelitis in Biozzi mice.

Experimental allergic encephalomyelitis (EAE) was induced in Biozzi AB/H (antibody high) mice by sensitization with spinal cord homogenate in adjuvant. Biozzi AB/H mice were highly susceptible to EAE induction and followed a chronic relapsing pattern of disease. Disease episodes were characterized by mononuclear infiltration of the central nervous system, with demyelination being particularly evident in relapse. The cellular infiltrates, which were associated with immunoglobulin deposition, consisted of macrophages and primarily CD4-positive T lymphocytes. However, similarly treated Biozzi AB/L (antibody low) mice were markedly less susceptible to EAE induction than AB/H mice. Thus, Biozzi mice should prove valuable for the study of chronic relapsing EAE.

Animals↗
PubMed1990

Endothelial cell expression of the intercellular adhesion molecule-1 (ICAM-1) in the central nervous system of guinea pigs during acute and chronic relapsing experimental allergic encephalomyelitis.

This study investigated the expression of intercellular adhesion molecule-1 (ICAM-1; CD54) by cells of the central nervous system (CNS) during acute experimental allergic encephalomyelitis (EAE) and chronic relapsing EAE (CREAE). In the CNS of normal guinea pigs, only a few endothelial cells expressed detectable levels of ICAM-1, whereas during the active phases of the disease ICAM-1 was present on cells of the perivascular infiltrate and the endothelia of both lesion- and non-lesion-associated blood vessels. In addition, cultured cerebrovascular endothelia maintained in 'standard' culture medium did not express ICAM-1, but they could be induced to express this antigen on incubation in a lymphocyte-conditioned medium. These findings suggest that the induction of ICAM-1 on CNS endothelia may be important in antigen presentation or in promoting lymphocyte extravasation across the blood-brain barrier in inflammatory disorders of the CNS.

Animals↗
PubMed1990

Improving state-funded child psychiatric care: reducing protracted hospitalizations through changes in treatment planning.

In late 1986, Millcreek Psychiatric Center for Children changed several of its treatment practices in an attempt to decrease needlessly prolonged hospitalizations. The changes included initiating discharge planning shortly after admission, increasing contacts with community and judicial agencies, improving family therapy services, and educating the community about appropriate use of hospital treatments. The fraction of children hospitalized more than 180 days decreased significantly, as did the average length of stay. Mental health professionals should keep community agencies informed about the nature and limitations of inpatient treatment and about children's needs for adequate after-care services.

Adolescent↗
PubMed1990

GTP-binding Ypt1 protein and Ca2+ function independently in a cell-free protein transport reaction.

The 21-kDa GTP-binding Ypt1 protein (Ypt1p) is required for protein transport from the endoplasmic reticulum to the Golgi complex in yeast extracts. Ypt1 antibodies block transport; this inhibition is alleviated by competition with excess purified Ypt1p produced in bacteria. Furthermore, extracts of cells carrying the mutation ypt1-1 are defective in transport, but transport is restored if a cytosolic fraction from wild-type cells is provided. The in vitro transport reaction also requires physiological levels of Ca2+. However, Ypt1p functions independently of Ca2+. First, buffering the free Ca2+ at concentrations ranging from 1 nM to 10 microM does not relieve inhibition by Ypt1 antibodies. Second, consumption of a Ca2+-requiring intermediate that accumulates in Ca2+-deficient incubations is not inhibited by anti-Ypt1 antibodies, although completion of transport requires ATP and an N-ethylmaleimide-sensitive factor. Thus, Ypt1p and Ca2+ are required at distinct steps.

Antibodies↗
PubMed1990

Antigen-restricted antigenic competition induced by 2,4-dinitrochlorobenzene: association with depression of lymphocyte proliferation.

2,4,6-Trinitrochlorobenzene (picryl chloride) and 2,4-dinitrochlorobenzene (DNCB) fail to cross-sensitize with respect to contact sensitivity in mice. Nevertheless, topical exposure of mice to DNCB and other skin-sensitizing dinitrobenzene derivatives was found to result in a significant impairment of draining lymph node cell proliferative responses induced following epicutaneous challenge with picryl chloride 5 days later. The inhibition of picryl chloride induced proliferation was associated with an impairment of contact sensitization to this chemical. The effect of DNCB on subsequent responses to picryl chloride was transient and no longer detectable 15 days following exposure. The inhibition of proliferation and contact sensitization caused by DNCB was largely restricted to picryl chloride. Thus, DNCB failed to influence the development of contact allergy to the unrelated chemical 4-ethoxymethylene-2-phenyloxazol-5-one (oxazolone) and exerted a far less pronounced effect on oxazolone-induced proliferative responses. These data, therefore, describe an antigen-restricted form of antigenic competition which is associated with a depression of the primary lymphocyte proliferative response.

Animals↗
PubMed1990

Perforating eye injury in Allegheny County, Pennsylvania.

From 1980 through 1986, acute perforating eye injury (ICD codes 871.0-871.9) was diagnosed in 345 residents of Allegheny County, Pennsylvania. The mean incidence rate was 3.49 per 100,000 person years. There was no significant change in incidence over the seven-year period. The largest number of injuries occurred among individuals working with tools, of which 47 percent were occupational. Males had a 6.5-fold risk of injury relative to females. Blacks had a risk of 2.2 times that of Whites, mainly due to an excess of assaultive injuries. Individuals who had had recent ocular surgery accounted for 4.6 percent of cases overall, and for 31.6 percent of cases in those over age 60.

Adolescent↗
PubMed1990

Assessment of intestinal amino acid availability in cattle by use of the precision-fed cecectomized rooster assay.

The digestibilities of amino acids in duodenal digesta of steers were measured using a precision-fed cecectomized rooster assay. Freeze-dried duodenal digesta from steers fed five different diets were utilized. Amino acids present in digesta of steers fed diets supplemented with corn gluten meal were more digestible than those from digesta of steers fed diets supplemented with soybean meal, blood meal, fish meal, or no true protein source. Measurements of amino acid digestibility in the cecectomized rooster were similar to those obtained previously when measured with reference to chromic oxide in steers fitted with duodenal and ileal cannulae, suggesting that the precision-fed cecectomized rooster assay is an appropriate technique for estimating small intestinal digestibility of amino acids in cattle.

Amino Acids↗
PubMed1990

Requirements for antigenic competition in contact sensitivity.

The requirements for the induction of antigenic competition in murine contact sensitivity have been examined. Experiments with a variety of skin-sensitizing chemicals revealed a correlation between immunogenicity and the ability to inhibit subsequent responses to an unrelated contact allergen, oxazolone. Previous studies have suggested that, in contact sensitivity at least, antigenic competition is the consequence of a reduced lymphocyte proliferative response to the second antigen. We investigated whether the regulatory events which impair proliferation following exposure to the second antigen are induced as the result of a strong proliferative response to the first (competitor) antigen. It was found, however, that significant inhibition of the primary proliferative response to picryl chloride, by pretreatment of mice with either picryl sulphonic acid or 2,4-dinitrochlorobenzene, failed to prevent picryl chloride inducing antigenic competition for oxazolone. Our studies suggest that following topical exposure to potent skin allergens events other than proliferation in draining lymph nodes induce active immunoregulatory processes, one consequence of which is the appearance of antigenic competition.

Animals↗
PubMed1990

Is maintenance antiparkinsonian treatment necessary?

The authors designed a three-phase prospective trial in which only those patients who developed an acute, neuroleptic-induced extrapyramidal side effect (EPSE) received benztropine (BZ) at 2 mg i.m. and then 1 mg p.o. b.i.d. for 2 days after their symptoms were rated for severity and type (Preparatory Phase 1). They were then randomly assigned under double-blind conditions to continue BZ or be switched to placebo for 8 days (Experimental Phase 2). Finally in Phase 3 (Followup), all patients continued on placebo in a single-blind design until Day 30. If the patient re-experienced an acute EPSE that was of sufficient severity to require immediate BZ administration, he or she was rated, treated, and then dropped from the study. EPSE scores and dropout rates did not differ in Phase 2 between the placebo- and BZ-treated groups. Implications for the continuation, cessation, or intermittent use of antiparkinsonian (AP) drugs are discussed.

Adult↗
PubMed1990

Effect of joint motion on experimental calcium pyrophosphate dihydrate crystal induced arthritis.

We studied the effects of joint movement and immobilization on acute and chronic calcium pyrophosphate dihydrate (CPPD) crystal induced arthritis in lapine knee joints. Exercised CPPD injected joints, in both acute (single 10 mg CPPD intraarticular (IA), duration: 5 h) and chronic (repeated 10 mg CPPD IA, duration: 20 and 42 days) experiments, demonstrated a more intense histologic synovitis compared to cast immobilized knees (p = 0.0001). In chronic experiments, both CPPD injected and noninjected immobilized knees showed greater cartilage histopathologic-histochemical abnormalities (p less than 0.004) and significant reduction in cartilage hexosamine content (p less than 0.005), compared to exercised joints. CPPD injected knees, both exercised and immobilized, demonstrated an initial phase of increased cartilage biosynthetic activity (35S incorporation) at 20 days, compared to noninjected knees (p = 0.02), followed by a decline at 42 days (p less than 0.005). Our data indicate that joint movement enhances acute and chronic experimental CPPD crystal induced synovitis. Articular cartilage is more adversely affected by joint immobilization than by chronic crystalline inflammation. An optimum balance between exercise and rest seems necessary for patients with arthritis so that cartilage can be preserved but pain from active inflammation also controlled.

Animals↗