PubMed Health⌕ Search

Biomedical subjects

D D White

Publications and source records attributed to D D White.

16 recordsLinked to original sources
PubMed1999

A quantitative and qualitative reanalysis of the endocast from the juvenile Paranthropus specimen l338y-6 from Omo, Ethiopia.

Based on an analysis of its endocast, Holloway (1981 Am J Phys Anthropol 53:109-118) attributed the juvenile Omo L338y-6 specimen to Australopithecus africanus (i.e., gracile australopithecines) rather than to Paranthropus (Australopithecus) boisei (robust australopithecines) favored by other workers (Rak and Howell [1978] Am J Phys Anthropol 48:345-366). Holloway's attribution was based on the specimen's (1) low cranial capacity, (2) gracile-like meningeal vessels, (3) gracile-like cerebellar hemispheres, and (4) absence of an enlarged occipital/marginal (O/M) sinus system. Recent work, however, has shown that criteria 1 and 2 are not useful for sorting gracile from robust australopithecines (Culotta [1999] Science 284:1109-1111; Falk [1993] Am J Phys Anthropol 92:81-98). In this paper, we test criterion 3 by quantifying the endocranial cerebellar and occipital morphology reproduced on the Omo L338y-6 endocast, and comparing it to seven endocasts from South and East African early hominids. Our preliminary results show that metric analysis of this specimen cannot be used to sort it preferentially with either robust or gracile australopithecines. Finally, we demonstrate that, contrary to previous reports, the Omo L338y-6 endocast reproduces an enlarged left occipital sinus (criterion 4). This observation is consistent with the original attribution of the Omo specimen to robust australopithecines (Rak and Howell [1978] Am J Phys Anthropol 48:345-366). Furthermore, if Omo L338y-6 was a robust australopithecine, this discovery extends the occurrence of an enlarged O/M sinus system to one of the earliest known paranthropines. Am J Phys Anthropol 110:399-406, 1999.

Animals↗
PubMed1996

Sucrose as an analgesic agent for infants during immunization injections.

OBJECTIVE: To assess the effectiveness of sucrose as an analgesic agent during routine immunization injections for infants (age range, 2 weeks to 18 months). STUDY DESIGN: Double-blind, randomized control trial. SETTING: Ambulatory care clinic of a large tertiary care center. PARTICIPANTS: A consecutive sample of 285 infants were randomly assigned to one of three treatment groups. INTERVENTION: Subjects received either no intervention or drank 2 mL of sterile water or 2 mL or a 12% sucrose solution 2 minutes before administration of the immunization. MAIN OUTCOME MEASURE: Infants were videotaped during immunization for later interval recording of pain-induced vocalizations. RESULTS: Results were analyzed by using two-way repeated measure analyses of variance. Two-week-old infants who received either the sterile water or sucrose solution cried significantly less than infants who received no intervention (F=5.92,P<.005). For older infants, those who received water or sucrose cried significantly less only if they were administered one injection rather than two injections (F=3.36,P<.05). CONCLUSIONS: We found that when infants drank sucrose or sterile water, significantly fewer pain vocalizations were produced, but only for 2-week-old infants. For older infants, differences were found only when the number of injections was included in the analysis. We expand on previous findings by demonstrating that both the age of the child and the number of painful exposures can attenuate calming effects. In addition, the results suggest that in the absence of nonnutritive sucking, the actual analgesic effects of sucrose may be nonspecific. Further study is needed of the possible analgesic effects of sucrose.

Age Factors↗
PubMed1996

Women have lower tolerance to lower body negative pressure than men.

Studies of the cardiovascular response to lower body negative pressure (LBNP) in men and women have suggested that women may have less tolerance to LBNP than men, although tolerance per se was not determined. To investigate the effect of gender on tolerance to LBNP, 10 men 10 women were subjected to increasing levels of LBNP until presyncopal symptoms developed. The cumulative stress index (CSI) score was determined, as were cardiovascular variables. Women had 62% less tolerance to LBNP with a CSI of 412 +/- 43 mmHg/min compared with a CSI of 1,070 +/- 149 mmHg/min for men. Cardiovascular changes associated with LBNP were similar for men and women when expressed relative to the occurrence of presyncope, but women had a higher heart rate response when the data were expressed at absolute levels of LBNP (-30 and -50 mmHg LBNP). Thus men and women had similar cardiovascular adjustments to the LBNP, with the changes in women occurring lower levels of LBNP. These data are important in a consideration of the development of antigravitational countermeasures for women. These data raise questions as to the manner in which blood pools within the lower body in men and women under LBNP.

Adult↗
PubMed1996

Pelvic blood pooling of men and women during lower body negative pressure.

INTRODUCTION: The objective of this study was to investigate possible gender differences in the hemodynamic responses of the lower body during lower body negative pressure (LBNP). METHODS: In this study, 17 women (mean age = 56 yrs) and 15 men (mean age = 55 yrs) underwent a 15 min exposure to -50 mm Hg LBNP. A Beckman (BR-100) Impedance Plethysmograph was used to measure each subject's leg and pelvic blood flow and pooling during the LBNP test. RESULTS: The women had an 83% greater increase in blood volume in the pelvic region than men as a result of the LBNP exposure. Women and men had similar increases in leg blood volume as a result of the 15 min exposure to -50 mm Hg. There was no significant gender difference in the decreased amount of blood flow to the leg or pelvic regions by the end of -50 mm Hg LBNP. CONCLUSIONS: These results demonstrate that women have greater blood pooling in the pelvic region compared to men when exposed to -50 mm Hg LBNP. These results should be considered when designing life-support equipment for men and women pilots and astronauts, especially the designing of anti-G and Space Shuttle re-entry garments.

Aged↗
PubMed1983

A homogeneous sol particle immunoassay for total oestrogens in urine and serum samples.

Conjugates prepared by adsorption of antibodies to colloidal gold particles were used in a homogeneous sol particle immunoassay for total oestrogens. The assay is based on inhibition by free oestrogens in the sample of the agglutination of a reaction mixture, consisting of the sample, the gold particle anti-oestriol conjugate and a suitable amount of oestriol-16/17-monosuccinyl-bovine serum albumin. The effect of different assay conditions is discussed. Under optimum conditions for an assay performed at room temperature the measuring range for E3 in buffer was 2-10 ng/ml. After appropriate pretreatment of samples the assay can be used to quantitate the level of total oestrogens in both urine and serum. The within-run coefficient of variation was 6.3% and over-all 6.9%. This method is also suitable for the assay of other haptens.

Colloids↗
PubMed1980

Action of gold salts in some inflammatory and immunological models.

Several gold salts were compared in kaolin-induced rat paw oedema, u.v. erythema in guinea pigs, delayed type hypersensitivity and humoral immunity in mice, and adjuvant-induced arthritis in the rat. In the latter the additional parameters of serum gold and copper levels and lysosomal enzyme activity were determined. In addition, the in vitro inhibition of several lysosomal enzymes derived from mouse macrophages was studied. The gold compounds examined were aurothiomalate, aurothioglucose, triethylphosphine gold chloride (SK & F 36914) and its glucopyranoside derivative (SK & F D-39162), triphenylphosphine gold chloride and sodium gold chloride dihydrate. SK & F 36914 and SK & F D-39162 has significant activity after oral dosage upon paw kaolin and u.v. erythema in rats and guinea pigs, respectively. Gastric swelling also occurred. In Wistar rats, adjuvant arthritis was little affected by the gold salts but in the Lewis rats there was suppression. In both strains there was less elevation in serum copper levels with treatment by SK & F 36914 and SK & F D-39162, but not by aurothiomalate. None of the compounds had any measurable effect on delayed hypersensitivity or humoral antibody levels in mice. The in vitro activities of cathepsin B1 and cathepsin D were inhibited by all the gold compounds. Reactivity of gold compounds with glutathione and cysteine in vitro was dependent on compound solubility and the nature of the gold ligand. Considerable differences exist between the profiles of activity for the different gold salts evaluated. These observations indicate that some gold salts do possess anti-inflammatory activity with a potency similar to that of indomethacin.

Animals↗
PubMed1976

Isolation and characterization of human plasma alpha 1-proteinase inhibitor and a conformational study of its interaction with proteinases.

1. alpha 1-Proteinase inhibitor was isolated from human plasma by a five-step procedure. Isoelectric focusing showed that six components focused between pH4.85 and 4.95. 2. The mol.wt. of the inhibitor was 52000 by sedimentation equilibrium and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The amino acid and carbohydrate compositions of the inhibitor were also determined. 3. The far-u.v.c.d. (circular-dichroism) spectrum indicated that the inhibitor had about 36% alpha-helical content. 4. The loss of proteinase-inhibitory activity when the inhibitor was exposed to pH values less than 5.0 or greater than 10.5 was accompanied by small changes in the far-u.v.c.d. spectrum and large changes in the near-u.v.c.d. spectrum. The change at alkaline pH was associated with ionization of tyrosine residues. 5. Interaction of inhibitor with chymotrypsin caused perturbation of the c.d. spectrum and this was used to follow the interaction and show a 1:1 stoicheiometry. 6. C.d., electrophoresis and isoelectric focusing showed that the inhibitor-enzyme complex is degraded by free enzyme. 7. Parallel studies with trypsin indicated that it too forms a 1:1 complex with inhibitor and is degraded by excess of enzyme.

Amino Acids↗
PubMedDate not supplied

Stress and the hospital administrator: sources and solutions.

Each day, more is learned about the nature and impact of executive stress. Only recently, however, has there been concern about the specific causes of stress faced by managers in different organizational settings. This article presents the findings of a study designed to identify sources of stress associated with the tasks, roles, and social relationships of hospital administrators. Seventy-one administrators of general short-term hospitals completed extensive questionnaires reflecting factors influencing stress in their work and diseases related to those factors. In addition, in-depth interviews with ten administrators provided further insights into the hospital work environment and its relation to stress. Although numerous conditions were reported by administrators to heighten stress levels on the job, other factors not readily recognized as stress producing appeared to be related to physical and psychological disorders. Implications of the findings for administrative practice are also presented.

Data Collection↗