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Biomedical subjects

R S Chapman

Publications and source records attributed to R S Chapman.

At least 55 records · Page 3Linked to original sources
PubMed1991

Smoking and other risk factors for lung cancer in Xuanwei, China.

In Xuanwei County, Yunnan Province, lung cancer mortality rates are among the highest in China in both males and females. Previous studies have shown a strong association of lung cancer mortality with indoor air pollution from 'smoky' coal combustion. In the present case-control study, 110 newly-diagnosed lung cancer patients and 426 controls were matched with respect to age, sex, occupation (all subjects were farmers), and village of residence (which provided matching with respect to fuel use). This design allowed assessment of known and suspected lung cancer risk factors other than those mentioned above. Data from males and females were analysed by conditional logistic regression. In females who do not smoke, the presence of lung cancer was statistically significantly associated with chronic bronchitis (odds ratio [OR] = 7.37, 95% confidence interval [Cl]: 2.40-22.66) and family history of lung cancer (OR 4.18, 95% Cl: 1.61-10.85). Females' results also suggested an association of lung cancer with duration of cooking food (OR 1.00, 9.18 and 14.70), but not with passive smoking (OR 0.77, 95% Cl: 0.30-1.96). In males, lung cancer was significantly associated with chronic bronchitis (OR 7.32, 95% Cl: 2.66-20.18), family history of lung cancer (OR 3.79, 95% Cl: 1.70-8.42), and personal history of cooking food (OR 3.36, 95% Cl: 1.27-8.88). In males a dose-response relationship of lung cancer with smoking index (years of smoking*amount of smoking) was shown by risks of 1.00, 2.61, 2.17 and 4.70.

Case-Control Studies↗
PubMed1991

Specificity of two-site immunometric assays.

The assessment of specificity in two-site immunometric assays is complex. Conventional approaches based on standard substitution with cross-reactant may yield misleading results. An 'in-house' immunoradiometric assay (IRMA) for human growth hormone (hGH) appeared free from cross-reactivity with human placental lactogen (hPL) in a single point standard substitution experiment performed by the United Kingdom External Quality Assessment Scheme (UK EQAS). However, detailed studies based on the substitution of hGH standards with hPL cross-reactant, the addition of hPL cross-reactant to hGH standards and the recovery of added hGH from endogenous cross-reactant (sera from pregnant subjects) revealed gross cross-reactivity of hPL in the hGH assay. We recommend that the validation of assay specificity should require the demonstration of quantitative recovery of a range of analyte concentrations from human sera that contain varying endogenous concentrations of cross-reactant.

Calibration↗
PubMed1991

A two-site immunoradiometric assay for PTH(1-84) using N and C terminal specific monoclonal antibodies.

We report the development of a two-site immunoradiometric assay for PTH(1-84) based on two site-specific monoclonal antibodies--3B3 (radiolabelled antibody) specific for PTH(1-34) and ESQ1 (on solid phase) specific for PTH(74-84). Antibody 3B3 is sensitive to the oxidation of the methionine residues in PTH(1-34) therefore hydrogen peroxide (0.1 M) is added to the incubation mixture. Validation studies confirm quantitative recovery of both oxidized and reduced PTH(1-84). The assay has a minimum detection limit of 0.5 pmol/L and a range of 1.5-250 pmol/L with an intra-assay CV of less than 10% (2.8-250 pmol/L less than 5% CV). Studies on clinical samples indicate good discrimination between normal subjects (mean 2.21; range 1.0-5.0 pmol/L) and patients with primary hyperparathyroidism (mean 21.0; range 5.8-100 pmol/L) who in turn are well separated from patients with hypercalcaemia of malignancy (14/18 less than 0.5 pmol/L).

Adult↗
PubMed1991

An epidemiological study of lung cancer in Xuan Wei County, China: current progress. Case-control study on lung cancer and cooking fuel.

In Xuan Wei County, Yunnan Province, lung cancer mortality rates are among China's highest in males and females. Previous studies have shown a strong association of lung cancer mortality with air pollution from "smoky" coal combustion. In the present quantitative risk assessment of indoor air pollution study, the result strongly shows an obvious on-site exposure-response relationship between benzo[a]pyrene concentration in indoor air and lung cancer mortality and strongly supports the hypothesis that indoor air pollution is the main risk factor in inducing lung cancer in Xuan Wei County. In the present case-control study, the result shows that in females, the presence of lung cancer is statistically significantly associated with chronic bronchitis and family history of lung cancer. The results also suggest an association of lung cancer with duration of cooking food, but not with passive smoking. In males, the presence of lung cancer is associated with smoking, bronchitis, family history of lung cancer, and personal history of cooking food.

Air Pollution, Indoor↗
PubMed1990

Fast mapping of words in event contexts by children with Down syndrome.

Fast mapping of novel words for objects was compared in 48 children and adolescents with Down syndrome (ages 5:6-20:6), who were delayed in expressive language acquisition compared to mental age, and 48 normally developing children matched for mental age (chronological ages 2:0-6:0). Normal and Down syndrome groups did not differ in their ability to infer a connection between the novel word and referent (100% vs. 100%), to comprehend the novel word after a single exposure (83% vs. 73%), and to recall the location in which they hid the novel referent (83% vs. 75%). Nor did they differ in their ability to produce the novel word correctly (at least two out of three phonemes in order: 48% vs. 40%). When retested after an hour of other activity, only the production task showed a significant, and comparable, decrement. Comparing youngest and oldest quarters of each group showed improved memory for location in both, improved comprehension in the Down syndrome group, and improved production in the control group. Adults (n = 12), in contrast, performed perfectly on all tasks except the delayed word production. Neither intelligibility differences nor use of real word labels accounts for the failure to find a difference between groups. Fast mapping skills were unrelated to expressive language deficit in these children with Down syndrome.

Adolescent↗
PubMed1989

Application of solid-phase antibodies to radioimmunoassay. Improved performance of Dynospheres following affinity purification of antisera.

Affinity purification of antibody before covalent binding to pre-activated micro-particles (Dynospheres) was necessary to overcome the reduced coupling capacity evident with low titre antisera, particularly antihapten sera. Optimally prepared Dynospheres anti-thyroxine provided a radioimmunoassay with good performance and economical usage of microparticles. Assay sensitivity was less than 10 nmol/l while precision across the clinically relevant dose range (50-150 nmol/l) was 3% CV using 125 micrograms particles per assay tube.

Antigen-Antibody Reactions↗
PubMed1989

How sensitive are immunometric assays for thyrotropin?

The usual method for calculation of the "sensitivity" of thyrotropin immunometric assays is multireplicate analysis of the zero analyte standard. Although this is a statistically valid estimate of the scatter likely to be found in the response variable, it is unrelated to normal analytical practice (usually analysis in duplicate) and estimates intra-assay errors only. This study was designed to assess the analytical performance of 10 immunometric assays used routinely for measurement of thyrotropin in human serum. Response data from each assay were accumulated to provide (a) an estimate of "sensitivity" from multireplicate analysis and (b) an estimate of "minimum detection limit," relating directly to errors associated with routine performance and derived from a minimum of 500 duplicate analyses. We conclude that the "minimum detection limit" should be promoted as a more meaningful measure of assay performance at low analyte concentrations than the "sensitivity" derived from multireplicate analysis of the zero-analyte standard.

Evaluation Studies as Topic↗
PubMed1988

Early receptive and productive language skills in preterm and full-term 8-month-old infants.

Early receptive and productive language skills were examined for preterm low birthweight infants and full-term normal birthweight infants from middle-class homes. Nineteen preterm infants and 19 full-term infants were observed in a laboratory setting at the gestationally corrected age of 8 months. To avoid the frequent confound between prematurity and low socioeconomic status, mothers of the two groups of infants were matched on educational levels. Regression analyses were used to assess the relative influence of infant cognitive skills, infant sociability, infant birth status, and the mothers' language input as possible predictors of infant receptive language and vocal behavior. Receptive language skills were associated with higher cognitive performance, greater sociability, and preterm birth. Productive language skills were associated with higher cognitive performance. On the basis of this research, the prognosis for language development in preterm infants raised in middle-class homes appears to be excellent.

Child Language↗
PubMed1988

Communication breakdowns in normal and language learning-disabled children's conversation and narration.

The frequency and type of communication breakdowns occurring in the speech of 7 language learning-disabled children (LLD), aged 9:10-11:1 (years:months), were examined in two conditions, conversation and narration, and compared to a group of 7 normal peers matched for chronological age and 7 peers matched for mean length of communication unit in conversation. Types of communication breakdowns examined included stalls, repairs, and abandoned utterances. The LLD group incurred a significantly greater rate of communication breakdowns per communication unit in narration than conversation compared to control group differences. Mean length of communication unit was also significantly greater in narration than conversation for the LLD group compared to controls. For all groups, across both speech sample conditions, longer communication units contained more breakdowns than shorter ones. The groups did not differ in the types of breakdowns. Communication unit length and the nature of the narrative task may account for the increased dysfluencies in LLD children's speech.

Child↗
PubMed1987

Performance of the two-site immunoradiometric assay for serum thyroid-stimulating hormone. Effects of changes in solid-phase matrix and antibody coupling chemistry.

Ten solid-phases were evaluated for their usefulness in a two-site immunoradiometric assay for serum thyroid-stimulating hormone. The criteria used to assess each reagent included the minimum detection limit attainable, the change of binding over the concentration range (signal: noise ratio), and ease of preparation of the reagents. Of all the solid phases tested, Sepharose CL-4B and activated CH-Sepharose 4B showed the characteristics best suited to IRMA, while epoxy-activated Sepharose 6B and Ultrogel ACA-44 were marginally less effective.

Antibodies, Monoclonal↗
PubMed1987

Lung cancer and indoor air pollution in Xuan Wei, China.

In Xuan Wei County, Yunnan Province, lung cancer mortality is among China's highest and, especially in females, is more closely associated with indoor burning of "smoky" coal, as opposed to wood or "smokeless" coal, than with tobacco smoking. Indoor air samples were collected during the burning of all three fuels. In contrast to wood and smokeless coal emissions, smoky coal emission has high concentrations of submicron particles containing mutagenic organics, especially in aromatic and polar fractions. These studies suggested an etiologic link between domestic smoky coal burning and lung cancer in Xuan Wei.

China↗
PubMed1987

Story recall and inferencing skills in language/learning-disabled and nondisabled children.

Children's ability to recall information and draw inferences from orally presented narratives was examined in sixteen 9- to 10-year-old language/learning-disabled (LLD) children and two groups of normally developing children (sixteen 9- to 10-year-olds and sixteen 6- to 7-year-olds). Short fable-like stories were presented to the children, followed by a series of premise and inference questions (half true and half false). The children were also asked to retell each story in their own words either before or after the question sets. Significant overall differences in performance (p less than .05) were seen between the LLD group and the age-matched control group and between the two control groups. The LLD children did not differ significantly from the younger aged control group. Additionally the LLD group exhibited significantly more disparity between the true and false questions than the age-matched controls. For all the groups, inference questions were significantly more difficult than premise questions. Recall of the story prior to answering questions had no effect on question answering.

Child↗