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Biomedical subjects

L Barbour

Publications and source records attributed to L Barbour.

9 recordsLinked to original sources
PubMed2000

Improving synthetic lethal screens by regulating the yeast centromere sequence.

The synthetic lethal screen is a useful method in identifying novel genes functioning in an alternative pathway to the gene of interest. The current synthetic lethal screen protocol in yeast is based on a colony-sectoring assay that allows direct visualization of mutant colonies among a large population by their inability to afford plasmid loss. This method demands an appropriate level of stability of the plasmid carrying the gene of interest. YRp-based plasmids are extremely unstable and complete plasmid loss occurs within a few generations. Consequently, YCp plasmids are the vector of choice for synthetic lethal screens. However, we found that the high-level stability of YCp plasmids resulted in a large number of false positives that must be further characterized. In this study, we attempt to improve the existing synthetic lethal screen protocol by regulating the plasmid stability and copy number. It was found that by placing a yeast centromere sequence under the control of either inducible or constitutive promoters, plasmid stability can be significantly decreased. Hence, altering the conditions under which yeast cells carrying the plasmid PGAL1-CEN4 were cultivated allowed us to develop a method that eliminated virtually 100% of false positives and drastically reduced the time required to carry out a synthetic lethal screen.

Aminohydrolases↗
PubMed1998

Alveolar-arterial oxygen gradient in acute pulmonary embolism in pregnancy.

OBJECTIVE: Our goal was to determine the prevalence of normal alveolar-arterial gradients in pregnant patients with documented pulmonary embolism. STUDY DESIGN: A retrospective chart review was performed on all pregnant women with pulmonary embolism at two large obstetric centers between 1990 and 1995. Alveolar-arterial gradients were calculated from room air arterial blood gas values and compared with values from patients who had been established as normal. RESULTS: Ten of 17 patients with pulmonary embolism identified had alveolar-arterial gradients that were normal. CONCLUSIONS: In our study 58% of pregnant women with documented pulmonary embolism had a normal alveolar-arterial gradient. This markedly differs from the published data in nonpregnant patients, in which the incidence of normal alveolar-arterial gradients in pulmonary embolism has ranged from 1.9% to 20%. This suggests that the alveolar-arterial gradient should not be used to determine the likelihood of pulmonary embolism in pregnant women because this could lead to the withholding of appropriate treatment for this life-threatening condition.

Adolescent↗
PubMed1994

Urinary element concentrations in kidney stone formers and normal controls: the week-end effect.

Early morning urines were collected on each of three days (Monday-Wednesday) from 19 male stone-formers and 20 healthy male controls. Concentrations of 10 elements were determined using inductively coupled plasma atomic emission spectroscopy, graphite furnace atomic absorption spectroscopy and particle induced x-ray emission spectrometry. Data were treated using multivariate statistical methods. The results showed that the concentrations of several elements in the control urines were significantly raised on Mondays and that controls and stone formers differed with respect to certain elements, also on Mondays. The observed elevations were termed the "weekend effect". It is suggested that while stone-formers may regulate their diets throughout the entire week, normals may indulge in dietary excesses over the weekend. The weekend effect highlights the danger of placing too much emphasis on a single measurement of a urinary parameter and alerts investigators to take cognizance of the day on which urine collections are effected, especially when attempting to identify abnormal renal excretion patterns in stone-formers by comparison of their urinary variables with those of controls.

Humans↗
PubMed1991

Preschool siblings of handicapped children: interactions with mothers, brothers, and sisters.

The purpose of this investigation was to examine similarities and differences between young (aged 3 years to 6 years 9 months) siblings of handicapped and nonhandicapped children in their behavioral interactions with their mothers, brothers, and sisters. Behavior of mothers toward the different groups of children also was examined. Results revealed few differences between sibling groups in the quantity or quality of their interactions with family members. In comparison to the matched control children, siblings of handicapped children engaged in more parallel play and social play, and were more nurturing but no more likely to interact aggressively or to be commanding or directive with their brothers or sisters. Mothers in the experimental group were found to target significantly more nurturant behaviors toward their children compared to control mothers and were significantly more likely to deliver commands, directives, and reprimands to siblings of handicapped children than to any other child. Results are discussed in terms of their correspondence to previous observational and interview research.

Child↗
PubMed1990

Social interactions of obese and nonobese women.

The stigma associated with obesity is likely to limit the opportunities obese women have to develop social skills. This hypothesis was tested by having obese (n = 15) and nonobese (n = 22) women converse on the telephone with college students who were unaware of the women's weights. Ratings made by judges who listened to the women's contributions to the conversations but who were unaware of their weights showed that obesity was negatively related to judgments about the women's likability, social skills, and physical attractiveness. The telephone partners of obese women rated the women and themselves more negatively than did the partners of nonobese women. Obese and nonobese women generally did not differ in their evaluations of their own and their telephone partners' behavior, and they also did not differ on a measure of social self-esteem. These findings suggest that there are real differences in the social behavior of obese and nonobese women and that these differences affect the impressions formed by those with whom they interact.

Adult↗
PubMed1987

Psychosocial characteristics of preschool siblings of handicapped and nonhandicapped children.

This project examined psychosocial characteristics of 24 preschool-aged siblings of handicapped children in relation to a control group of 22 siblings of nonhandicapped children. Subjects were matched on family size and income, sibling age, birth order, sex, age spacing, and marital status of their parents. Results indicated no statistically significant differences between groups of children on measures of perceived self-competence and acceptance, understanding of developmental disabilities, empathy, and child care responsibility. Significant group differences were found where brothers of handicapped children were rated by their mothers as being more depressed and aggressive than brothers of nonhandicapped control children. Sisters of handicapped children were rated by mothers as being more aggressive than sisters of nonhandicapped children. Sisters of handicapped children and brothers of nonhandicapped children had significantly fewer privileges and more restrictions on their home activities than other groups. Results are discussed in relation to previous research on older siblings of handicapped children and the general literature on family stress and childhood disability and disease. The importance of examining sibling functioning via multiple measures of child behavior is stressed.

Aggression↗