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Biomedical subjects

H Bunce

Publications and source records attributed to H Bunce.

At least 19 recordsLinked to original sources
PubMed1989

Aromatic amines and acetamides in Salmonella typhimurium TA98 and TA100: a quantitative structure-activity relation study.

The mutagenicity of a series of 19 aromatic amines had been previously measured in Salmonella typhimurium strains TA98 (frame-shift) and TA100 (base-pair) with the addition of S9 from Aroclor 1254-induced rat liver. A quantitative structure-activity relation (QSAR) study using multiple regression analysis points out the influence of three factors on mutagenicity: lipophilic character, position of the amine group, and whether it is free or acetylated, as expressed by log P and two indicator variables I1 and I2, respectively. The multiple regression equations explain 78 and 88% of the variance in log mutagenicity in TA98 and TA100, respectively. First of all, mutagenicity was shown to increase with lipophilicity. On the other hand, mutagenicity is reduced when the amine or acetamido position is ortho to the juncture because of steric hindrance in its biotransformation compared with a non-ortho isomer. It is decreased also by the acetylation of the amine group, probably because the acetyl group needs to be first split off prior to oxidation of the amine group to -NHOH.

Acetamides↗
PubMed1983

Comparing survival of responders and nonresponders after treatment: a potential source of confusion in interpreting cancer clinical trials.

The comparison of survival distributions between patients who respond to therapy and those who do not can present methodologic and interpretational difficulties. Since assignment of patients to the responder or nonresponder groups is not random, statistical procedures that test the equality of survival distributions only demonstrate association between response and survival, not cause and effect. This association may have no relevance to the efficacy of treatment. The assignment of patients to response categories also represents a methodologic problem. Variability in the definition of a nonresponder and the handling of early deaths can both lead to varying conclusions concerning survival. In spite of these problems, statistical comparisons of survival distributions of responders and nonresponders are reported in approximately 20% of phase II and phase III clinical trials. Descriptive statistics may be more useful than inferential statistics in this situation.

Clinical Trials as Topic↗
PubMed1983

Assessment of type A behavior in preschoolers.

Teachers and mothers of 219 four-year-old preschoolers assessed their children for Type A behavior pattern using the Matthews Youth Test for Health (MYTH). The sample was derived from five day care centers with Black, White, and Hispanic teachers and students from middle and lower class families. This study indicates that Type A behavior can be identified in four-year-old preschoolers on the basis of ratings by their teachers. A statistically significant difference was found between the ratings of Type A/B characteristics by teachers and those by mothers; however, these were not related to the sex or ethnicity of the children. Repeated measurements of Type A ratings in a subsample of the children at age five showed no significant change among boys or girls. However, repeated measurements at age six on a second subsample showed that boys had lower mean scores, i.e. were more Type B at age six than at age four.

Child, Preschool↗
PubMed1982

Supraglottic airway resistance in normal subjects and patients with occlusive sleep apnea.

We assessed the flow-impeding properties of nose and pharynx combined in four normals and five patients with occlusive sleep apnea (OSA) while awake by measuring supraglottic pressure and airflow at the nose. We calculated two indices of impedance presented by the supraglottic airway: the second coefficient (K2) of Rohrer's equation and supraglottic resistance (Rsg) at 0.4 l/s. The influence of posture and nasal mucosal circulation was evaluated by measuring these indices in sitting and supine position before and after administration of a nasal decongestant. The effects of changes in posture were similar in both normals and patients: K2 and Rsg values were significantly larger in supine than in sitting position. The nasal decongestant significantly decreased both values in sitting and supine positions for normals and patients but did not eliminate the posturally induced changes. Patients had significantly greater K2 and Rsg values than normals in all conditions. These results indicate supraglottic airway narrowing in OSA patients. This narrowing probably results from structural encroachment on the pharyngeal airway.

Adult↗
PubMed1980

Serum ferritin assay and bone-marrow iron stores in patients on maintenance hemodialysis.

Fifty-five patients on maintenance hemodialysis underwent bone-marrow aspirations for evaluation of iron stores that were to be compared to concomitant measurements of hematocrit, red blood cell volume, serum iron concentration, total iron binding capacity, transferrin saturation, and serum ferritin concentration. In 42 patients (76.4%), the bone marrow iron stores were found to be absent or deficient. Mean hematocrit for the total group was 26.4%, and red blood cell volume measurement showed a mean value of 41.1% of predicted normal. Results also indicated that serum ferritin was the best predictor of iron storage levels, with diagnostic thresholds of 80 to 350 ng/ml derived from statistical analysis of the data. Other hematologic parameters studied had significantly less correlation with bone-marrow iron stores.

Adult↗
PubMed1979

The house officer and the dying patient: attitudes, experiences, and needs.

A survey of house staff who care for dying patients was conducted at a large medical center and demonstrated that house officers are aware of their discomfort in dealing with dying patients and their families but believe they do not avoid them. They strongly agreed with the use of the "no code' designation and believed the quality of life was the most important factor in making that decision. The house officer who has concerns about a dying patient is most likely to talk with another house officer. The survey highlights the needs of house staff for experienced resource people and informal programs dealing with the care of dying patients.

Attitude of Health Personnel↗
PubMed1979

A comparison of absentee rates of elementary schoolchildren with asthma and nonasthmatic schoolmates.

Daily school attendance has been suggested as a health status measure for children. The present study compares school absence in children known to have asthma (N = 95) with a random sample of nonasthmatic elementary schoolchildren (N = 711). The differences in average percentage of days absent over one year were analyzed by comparing both groups' conditioning on ethnicity, sex, socioeconomic status, and grade. Children with asthma have a significantly higher absentee rate (absent 8.4% of days) than do nonasthmatic children (absent 5.9% of days) (P less than 9001). This significant difference holds true regardless of ethnicity of sex and for most socioeconomic groups. A comparison by grade level shows a similar trend for children with asthma and nonasthmatic children: absentee rates decrease as children get older; however, except for one grade level, children with asthma have a greater percentage of school days absent. Mean absentee rates for children with asthma were different when compared according to their mother's perception of severity of asthma--mild (6.9%), moderate (7.9%), and severe (13.9%).

Absenteeism↗
PubMed1978

Mast cell analyses in hypertrophic scars, hypertrophic scars treated with pressure and mature scars.

Granulation tissues, hypertrophic scars, hypertrophic scars treated with mechanical pressure and mature scars from deep thermal injuries, or equivalent trauma, were examined for the presence and dermal distribution of mast cells. Statistical analyses of mast cell counts indicate that 1) the hypertrophic scar contains significantly greater numbers of mast cells than the other tissues studied. 2) as granulation tissue develops interstitial collagen, mast cells begin to appear, 3) mature scars contain significantly fewer mast cells than hypertrophic scars, 4) based on mast cell data, the effect of pressure therapy is first detected in the upper and middle reticularis of the dermis, and 5) on a mast cell statistical basis mature scar and hypertrophic scar under pressure are indistinguishable.

Burns↗
PubMed1977

Liver size in normal infants and children.

Liver span of normal infants and children 2 months to 5 years of age was found to be significantly correlated with body height, weight, surface area, and age. However, it was best correlated with body surface area, reflecting a constant relationship between body size and liver size. Assessment of liver span is a useful test for evaluation of a child with apparent liver enlargement.

Body Height↗