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Biomedical subjects

N Richardson

Publications and source records attributed to N Richardson.

34 records · Page 2Linked to original sources
PubMed1986

Anti-idiotypic sera against monoclonal anti-progesterone antibodies: production in rabbits and rats and characterization of specificity.

Antisera were raised in rabbits and rats against three mouse monoclonal anti-progesterone IgG1 antibodies. Anti-idiotypic antibodies were isolated from rabbit sera by successive passage over immunoadsorbent columns of normal mouse Ig and the specific immunizing monoclonal, with elution from the latter. Radioimmunoassays for anti-idiotype and free idiotype were established, enabling detection of idiotype in sera of mice immunized with progesterone-BSA conjugate. Binding of rabbit anti-idiotype to anti-progesterone monoclonals was partially inhibitable by free progesterone-hemisuccinate or progesterone-ovalbumin conjugate. While showing considerable specificity for their respective inducing monoclonals, the anti-idiotypes also cross-reacted in varying degrees with the other anti-progesterone monoclonals, demonstrating the presence of IdI and IdX determinants. The patterns of cross-reactivity showed some correlation with the relative isoelectric points and combining-site specificities of the anti-progesterones. The specificities of rat and rabbit anti-idiotypes were similar, but not identical.

Animals↗
PubMed1985

Effector functions of a monoclonal aglycosylated mouse IgG2a: binding and activation of complement component C1 and interaction with human monocyte Fc receptor.

Aglycosylated monoclonal anti-DNP mouse IgG2a produced in the presence of tunicamycin was compared with the native monoclonal IgG2a with respect to its ability to interact with the first component of complement, C1, and to compete with human IgG for binding to human monocyte Fc receptors. The aglycosylated IgG2a was found to bind subcomponent C1q with an equivalent capacity to the native IgG2a, but the dissociation constant was found to be increased three-fold. When activation of C1 by the glycosylated and aglycosylated IgG2a was compared, the rate of C1 activation by the aglycosylated IgG2a was reduced approximately three-fold. In contrast aglycosylation was accompanied by a large decrease (greater than or equal to 50-fold) in the apparent binding constant of monomeric IgG2a to human monocytes. The data suggest that the aglycosylated IgG2a has a structure which differs in the CH2 domain from the native IgG2a, and that the heterogeneous N-linked oligosaccharides of this monoclonal IgG2a which occur at a conserved position in the CH2 domain play a role in maintaining the integrity of its monocyte-binding site. This lack of monocyte binding may result either from a localized conformational change occurring in a single CH2 domain or from an alteration in the CH2-CH2 cross-domain architecture which is normally structured by a pair of opposing and interacting oligosaccharides. The minimal changes in C1q binding and C1 activation suggest that the oligosaccharides are, at most, indirectly involved in these events.

Animals↗
PubMed1985

A workplace health education program that reduces outpatient visits.

A workplace health education program aimed at reducing unnecessary outpatient visits was offered through 22 California employers. A total of 5,200 employees attended a presentation, received self-help books, and completed self-administered questionnaires. All visits for their households were monitored for up to 15 months. The study utilized a quasi-experimental staggered intervention design involving eight different cohorts, before/after comparisons, with statistical adjustment for seasonality and other intervening variables. Visit rates for households insured only by Blue Cross of California were reduced by 17% (P = 0.001), or 2.0 visits per household per year. For all participants, the reduction was 7.2% (P = 0.06), or 0.8 visits. Reductions were seen for all age and educational strata. The program was most effective among households with first dollar fee-for-service insurance coverage. Households with insurance requiring co-payments had less reduction. No reduction was seen among health maintenance organization (HMO) members. The study concludes that a minimal cost, self-care workplace intervention can reduce outpatient visits by important magnitudes.

Adult↗
PubMed1985

Enhancement of hydrophobic interaction, negative charge and phagocytosis by dinitrophenyl ligand coupling to Salmonella typhimurium 395 MS.

Dinitrophenylation of Salmonella typhimurium bacteria increased their hydrophobicity, negative charge, and interaction with PMNL in vitro, effects which are similar to the consequences of S-R mutation in S. typhimurium. The effects are ascribed to the hydrophobicity of the dinitrophenyl (DNP) ligand. Coupling of DNP-groups to the bacteria also enhanced their clearance by the reticuloendothelial system after intravenous injection into mice. Extensive DNP-coupling to the bacteria led to rapid deposition of injected bacteria outside the reticuloendothelial system. The kinetics of DNP-coupling showed saturation at 4-5 X 10(7) DNP groups per bacterium, similar for S and R bacteria, boiled and nonboiled. After 2 h of reaction with fluoro-2,4-dinitrobenzene (FDNB) more than 80% of the total DNP coupling observed after 4 h had occurred. The capacity of MOPC-315 IgA myeloma protein, which possesses anti-DNP activity, to bind to dinitrophenylated bacteria paralleled the number of DNP groups per bacterium, but smaller numbers of IgA molecules were bound. Approximately one IgA molecule bound per thousand DNP ligands. Only when bacteria were boiled prior to DNP coupling was agglutination observed after the addition of anti-DNP-IgA.

Binding Sites, Antibody↗
PubMed1985

The effects of binding mouse IgA to dinitrophenylated Salmonella typhimurium on physicochemical properties and interaction with phagocytic cells.

The binding of mouse IgA antibody to DNP-conjugated bacteria enhanced the hydrophobic interaction when measured in dextran-poly(ethyleneglycol) two-phase systems and hydrophobic interaction chromatography. Similarly the interaction with polymorphonuclear leukocytes in vitro increased. In contrast, the rate of clearance of IgA-reacted bacteria from the blood stream of mice, after intravenous injection, was reduced under the conditions tested. Our data showed, with respect to increased hydrophobic interaction and opsonization, that binding of IgA antibody to bacteria produced less pronounced effects than those of IgG antibody binding. In contrast, secretory IgA antibody binding has been shown to reduce hydrophobic interaction and phagocytosis. Thus, serum IgA antibody has properties intermediate to IgG and SIgA with respect to hydrophobicity and opsonization.

Animals↗
PubMed1985

Vigilance missed signals may have preferred average lags.

The randomness of average missed signal lags (AMSL) in experiments on vigilance was investigated. This measure was taken from group data in a sample of 116 published visual reports (on which an ad hoc cluster analysis was carried out) and from the 1966 results for 48 subjects tested by Smith, Lucaccini, Groth, and Lyman. Evidence of a 4-min. periodicity was found. This apparent effect of a biorhythm may extend the explanation of the absolute level of performance and, possibly, of the vigilance decrement. Depending on the effect-size, it might also have relevance for the practical problem of the maintenance of alertness.

Arousal↗
PubMed1977

Biosynthesis and characterization of intracellular IgDkappa in a case of CLL.

A case of chronic lymphocytic leukaemia (CLL) with diffuse intracellular IgDkappa is reported. No serum paraprotein or urinary Bence-Jones protein were detected. No surface immunoglobulin was found on the neoplastic lymphocytes, but the cells had receptors for Fcgamma and the C3 component of complement consistent with other cases of CLL. Biosynthetic studies confirmed that the cells synthesized IgDkappa but there was no evidence for secretion of IgD into the culture medium. The cells did not produce Ig of any other class. The intracellular IgD occurred predominantly as deltakappa units with no covalent links between the chains. These findings are discussed.

Binding Sites, Antibody↗
PubMedDate not supplied

The nurse as exercise leader.

Adherence rates to our nurse-led exercise interventions were considerably higher (88%) than those reported in the literature for overweight women of this age. Bonding between the women and the nurse leaders, as well as socialization opportunities and program design, may have contributed to this high rate. Future studies would be strengthened by comparing adherence rates of women between nurse-led and non-nurse-led exercise groups. Women tested at 3 and 6 months after the intervention stated they tried many fitness clubs and spas in the area, but could find no exercise programs that were tailored to their age and fitness level or that took into consideration their individual health needs. Nurses interested and knowledgeable about changes of aging are in an ideal position to develop and lead exercise programs for older individuals, particularly those with chronic nondisabling physical problems. Nurses in this study have expanded their health-promotion role by gaining knowledge and skills in exercise science. Resources available for any nurse to gain knowledge and experience about exercise are found in the resource list.

Aged↗
PubMedDate not supplied

Randomized controlled trial of cost reductions from a health education program: the California Public Employees' Retirement System (PERS) study.

Purpose. This study evaluated the cost trend reduction from a health promotion program. Design. A randomized 12-month trial comparing claims data was conducted. Additional studies, utilizing quasi-experimental designs, analyzed changes in health habits and changes in costs estimated by self-report. Subjects. All active California Public Employees' Retirement System (PERS) employees (21,170), non-Medicare eligible retirees (8,316), and retirees with Medical Supplement coverage (25,416) administered by Blue Shield of California were included. Intervention. The program consisted of mailed health risk assessments at six- or 12-month intervals, with individualized reports and recommendation letters sent to participants emphasizing and encouraging change, self-management materials emphasizing self-care when appropriate, and quarterly newsletters. Passive participants received printed materials only. Measures. Health risks were based upon self-report; summary scores were computed by modified Framingham algorithms. Self-report cost data were estimated from reported doctor visits, hospital days, and days sick or confined to home. Claims data were those paid by Blue Shield of California. Results. The program was associated with: 1) reduction in health risk scores at 12 months, (p less than .001), 2) reduction of subject reported medical utilization from baseline (p less than .05), and 3) decrease in claims cost growth relative to controls (p=.03). Annual claims costs were approximately $3.2 to $8.0 million less than expected had costs for the experimental participants increased at the same rate as the control group. Discussion. Results suggest that appropriately designed health promotion programs can reduce health risks and at the same time reduce the medical care claims cost trend.

Age Factors↗