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Biomedical subjects

L A Hall

Publications and source records attributed to L A Hall.

At least 55 records · Page 3Linked to original sources
PubMed1985

Supports, stressors, and depressive symptoms in low-income mothers of young children.

We investigated the association of social supports and stresses with depressive symptoms in a sample of 111 predominantly low-income mothers of young children. The prevalence of high depressive symptoms, as measured by the Center for Epidemiologic Studies--Depression Scale (CES-D), was 48 per cent. Among unmarried women, everyday stressors were strongly associated with depressive symptoms, while life events were weakly related. Associations between these variables were not found for married women. Comparing the relative importance of two different types of support--the quality of primary intimate relationships, and the social network--only the quality of the husband-intimate relationship was associated with CES-D scores among married women, whereas the social network demonstrated a moderate, inverse association with CES-D scores among unemployed women.

Adult↗
PubMed1983

Proprioceptive contributions to tactile identification of figures: dependence on figure size.

Studies on the recognition of objects or shapes explored by a hand or finger have concentrated on the relative merits of different methods of exploration--in particular, whether the exploring hand or finger is moved by the subject himself (active), is guided by an assistant (passive), or remains stationary with the shape being moved by an assistant (tactile). These factors, together with another variable--the size of the explored shape--were investigated in twelve normal adults whose task, without the aid of vision, was to explore and identify various shapes with the tip of the extended right index finger. Two series of shapes were used, a large (15 cm) and small (3 cm) series, both of which consisted of twelve shapes each being a variant of the letter 'S'. The shapes were outlined as rows of Braille-like dots on a flat surface. Exploration was also tested in the proprioceptive mode, in which the exploring hand was guided by an assistant around a shape which was simply drawn on the surface so as to give a minimum of tactile information. For neither large nor small shapes could we demonstrate differences between active, passive and proprioceptive exploration. For the small shapes, the active, passive and proprioceptive modes gave no advantage over purely tactile assessment. However, for the larger shapes, active, passive and proprioceptive modes allowed better identification than movement of the shape. Thus, purely cutaneous signals appear sufficient for optimal discrimination of small figures but proprioceptive signals, generated by movement, are needed for optimal discrimination of larger figures.

Humans↗
PubMed1983

Proprioceptive sensation at the terminal joint of the middle finger.

This paper extends previous work (Gandevia & McCloskey, 1976) on proprioception in the terminal joint of the middle finger. By positioning the finger in appropriate ways proprioceptive acuity at the joint can be assessed when no muscular afferents could contribute, or when afferents in the flexor but not the extensor could contribute, or when afferents from both muscles could contribute. Digital nerve block anaesthetizes joint and cutaneous receptors and so was used to study the contributions from muscle afferents in isolation. Displacements (10 degrees) at various angular velocities were better detected when muscle afferents from both flexor and extensor muscles could contribute. This was so whether joint and cutaneous receptors were also available, or after digital anaesthesia. Performance when only muscle afferents are available is, however, inferior to that when all sensory mechanisms are intact. It is concluded that muscle afferents contribute to kinaesthesia, and that a full complement of such receptors from agonist and antagonist muscles gives superior acuity to that achieved when only the receptors of one of the muscle groups is available. The angular displacements necessary for 70% correct detection were determined at angular velocities between 0.25 degrees and 160 degrees/s. Proprioceptive performance was optimal with all proprioceptive mechanisms intact over the range of angular velocities 10 degrees -80 degrees/s: 70% correct detection of displacements of 0.8 degrees-1.2 degrees occurred in this range. Performance deteriorated slightly at higher velocities of displacement. Performance was significantly poorer when only joint and cutaneous receptors could contribute (in the absence of intramuscular receptors), and when only intramuscular receptors could contribute (in the absence of joint and cutaneous receptors). Full proprioceptive acuity depends upon the availability of receptors in muscles and in skin and/or joints.

Finger Joint↗
PubMed1983

Detections of movements imposed on finger, elbow and shoulder joints.

The angular displacements necessary for 70% correct detection were determined in normal subjects at the shoulder and elbow joints and at the terminal joint of the middle finger. Angular velocities of displacement between 0.125 degrees and 160 degrees/s were tested. Each joint was tested in the mid-range of its normal excursion. The joints were carefully supported for testing and the muscles acting at the joints were relaxed. When assessed in terms of angular displacements and angular velocities, proprioceptive performance at the shoulder and elbow joints was superior to that at the finger joint. Optimal performance at the finger joint was attained over the range of angular velocities from 10 degrees to 80 degrees/s. Optimal performance at both more proximal joints was optimal over a wider range (2 degrees-80 degrees/s). Active pointing movements made without vision of the moving part were performed at each joint at velocities within the range of optimal proprioceptive performance. However, when detection levels and displacement velocities were expressed in terms of linear displacements and velocities at the finger tip for all three joints, the finger joint gave the best performance and the shoulder the worst. In practical terms, therefore, displacements of a given linear extent are best detected if they move distal joints and worst if they move proximal joints. For the elbow and finger joints the detection level and velocity data were expressed also in terms of proportional changes in the lengths of muscles operating at these joints, and as proportional changes in the distance between the points of attachment of the joint capsules. Analysis in terms of proportional changes of muscle length showed remarkably similar performance levels at both joints. This suggests that intramuscular receptors are important determinants of proprioceptive performance. Analysis in terms of joint capsular displacement did not unify the data: on this form of analysis proprioceptive performance at the elbow joint was superior.

Adult↗
PubMed1981

Syntheses of 9-acridine- and 2-phenanthridinemethanols as potential antimalarials.

alpha-(1-Piperidinylmethyl)-9-acridinemethanol (3), alpha-[(dibutylamino)ethyl]-9-acridanmethanol (4a), and alpha-[(dibutylamino)methyl]-2-phenanthridinemethanol (5) have been made and all are ineffective as antimalarials against Plasmodium berghei in mice. 9-Acridinyloxirane showed no significant mutagenicity for strains TA 98 or TA 100 of Salmonella typhimurium.

Acridines↗
PubMed1978

Automated treatment for flight phobia: a 3 1/2 year follow-up.

The authors contacted 43 patients who had been given audiovisual treatment for flight phobia 3 1/2--5 1/2 years previously. Of the 26 subjects who had flown successfully by the end of treatment, 23 had maintained their ability to fly at follow-up. Eighteen said their attitude toward flying was more positive since treatment, and 21 rated their comfort level while flying as "much better" or "better"; however, only 3 said they were "cured." Eleven patients said the treatment had helped to alleviate other fears or anxieties.

Aircraft↗
PubMedDate not supplied

Psychometrics for two short forms of the Center for Epidemiologic Studies-Depression Scale.

The Center for Epidemiologic Studies-Depression Scale (CES-D; L. S. Radloff, 1977) assesses the presence and severity of depressive symptoms occurring over the past week. Although it contains only 20 items, its length may preclude its use in a variety of clinical populations. This study evaluated psychometric properties of 2 shorter forms of the CES-D developed by F. J. Kohout, L. F. Berkman, D. A. Evans, and J. Cornoni-Huntley (1993): the Iowa form and the Boston form. Data were pooled from 832 women representing 6 populations. Internal consistency estimates, correlations with the original version of the CES-D, and omitted-included item correlations supported use of the Iowa form over the Boston form when a shortened version of the scale is desired. Regression statistics are provided for use in estimating scores on the original CES-D when either shortened form is used. Factor analytic results from two populations support a single-factor structure for the original CES-D as well as the short forms.

Adolescent↗
PubMedDate not supplied

Self-esteem as a mediator of the effects of stressors and social resources on depressive symptoms in postpartum mothers.

The purpose of this study was to examine the role of self-esteem as a mediator of the effects of stressors and social resources on mothers' postpartum depressive symptoms. Data were collected during in-home interviews with 738 women 1 to 2 months postpartum. Forty-two percent of the women had high depressive symptoms. Self-esteem mediated the effects of everyday stressors and the quality of primary intimate relationships on depressive symptoms. However, everyday stressors also exhibited direct effects. Mothers with low self-esteem were 39 times more likely to have high depressive symptoms than those with high self-esteem. Interventions to decrease postpartum mothers' chronic stressors and to improve the quality of their primary intimate relationships may enhance their self-esteem, which in turn may decrease the likelihood of high depressive symptoms.

Adolescent↗
PubMedDate not supplied

The effects of maternal psychosocial factors on parenting attitudes of low-income, single mothers with young children.

BACKGROUND: Although recent evidence implies linkages among depression or depressive symptoms, self-esteem, history of childhood abuse, and parenting attitudes, the evidence does not clearly elucidate the relationships among these variables. OBJECTIVES: To investigate the relationships among maternal psychosocial factors (history of childhood abuse, everyday stressors, self-esteem, and depressive symptoms) and parenting attitudes of low-income, single mothers who have young children. METHODS: Secondary analyses of data from in-home interviews with 206 low-income, single mothers from a southeastern United States urban area were conducted. A variety of scales, including the Adult-Adolescent Parenting Inventory (AAPI), were used to measure maternal psychosocial factors. RESULTS: Using the AAPI, a Modified Parenting Attitudes Measure (MPAM), and subscales, a three-stage regression procedure was used to test the model. For stages 1 and 2, everyday stressors were the strongest predictor of self-esteem. Childhood sexual abuse, everyday stressors, low self-esteem, and control variables accounted for 58% of variance in depressive symptoms. In the third stage for the AAPI, only control variables were retained except in the Lack of Empathy subscale, where depressive symptoms and control variables accounted for 16% of the variance. The third stage for the MPAM yielded, by subscale: Only control variables predicted Corporal Punishment Beliefs; depressive symptoms were the strongest predictor for the total MPAM (19% of variance) and of the Inappropriate Emotional Expectations subscale (17%); and childhood physical abuse was the only predictor of Role Reversal. CONCLUSIONS: Depressive symptoms mediated the effects of childhood abuse, everyday stressors, and self-esteem and provided the linkage between these variables and at-risk parenting attitudes. Self-esteem decreased as everyday stressors increased but did not directly affect parenting attitudes. A relationship was not found between childhood abuse and low self-esteem. This study highlights the complexity of parenting and the need to identify other factors of at-risk parenting not accounted for in this study.

Adolescent↗
PubMedDate not supplied

Mothers' potential for child abuse: the roles of childhood abuse and social resources.

BACKGROUND: The mechanism by which some victims of childhood abuse become abusive parents, whereas others do not, is not well understood. Previous empirical evidence indicates that social resources may modify the cycle of abuse or maladaptive parenting; however, the effects of different dimensions of social resources have not been compared. OBJECTIVES: To determine whether a measure of mothers' potential for physical child abuse was related to their retrospective reports of physical and sexual abuse before 18 years of age and to investigate the potential buffering effects of multiple dimensions of social resources on the relationship between childhood abuse and mothers' potential for physical child abuse. METHODS: The potential role of social resources as a moderator of the relationship between a history of childhood abuse and potential for physical child abuse was investigated in 206 low-income single mothers of young children. RESULTS: The levels of physical and sexual abuse in childhood were positively associated with the mothers' child abuse potential; sexual abuse displayed the strongest association. Compared with mothers who were not sexually abused in childhood, those reporting violent sexual abuse as children were almost six times more likely to have high potential for physically abusing their children. There was no evidence that any of the social resources modified the relationship of either type of childhood abuse with the mothers' potential for abuse. However, all four dimensions of social resources demonstrated significant main effects on child abuse potential. CONCLUSIONS: Low-income mothers face many stressors because of their lack of economic resources. This, coupled with a lack of social resources and a history of childhood abuse, makes low-income, single mothers particularly at risk for abusive parenting. The lives of these women and their children may be enhanced by assisting the women to improve their social resources which, ultimately, may reduce their potential for child abuse. Future research should focus on identifying factors that predict and/or modify the potential for abusive parenting as well as actual abuse.

Adult↗
PubMedDate not supplied

Negative thinking mediates the effect of self-esteem on depressive symptoms in college women.

BACKGROUND: One of every three women between 18 and 24 years of age may be significantly depressed. Younger women have shown increasing rates of unipolar depression since the 1950s, and the average age of onset continues to decline. OBJECTIVES: To examine the prevalence and correlates of high depressive symptoms in single college women 18 to 24 years of age. Negative thinking was posited to mediate the relationship between self-esteem and depressive symptoms. METHODS: A sample of 246 women was recruited from a university student body. Each woman completed a survey that included the Center for Epidemiologic Studies-Depression Scale, the Beck Depression Inventory, the Rosenberg Self-esteem Scale, the Crandell Cognitions Inventory, and the Automatic Thoughts Questionnaire. RESULTS: Of the women, 35% had high depressive symptoms. Negative thinking mediated the relationship between self-esteem and depressive symptoms. However, self-esteem also showed a weak direct effect on depressive symptoms. CONCLUSION: The findings suggest that negative thinking may play an important role in the development of depressive symptoms in college women.

Adult↗
PubMedDate not supplied

The hollow fiber assay: continued characterization with novel approaches.

The hollow fiber assay, a unique in vivo model, permits the simultaneous evaluation of compound efficacy against multiple cell lines in two physiological compartments. This assay has been used to characterize in vivo activity of cytotoxic compounds. The purpose of the present study was to characterize and optimize this assay for compounds with a defined mechanism of action, specifically cell cycle inhibition. Two human tumor cell lines and one normal human cell line were loaded into polyvinylidene fluoride hollow fibers at two or more cell concentrations and grown in mice for 3-10 days. The data demonstrate the importance of characterizing the initial loading density of various cell lines in the evaluation of compounds. All studies were performed with cells in the linear part of the cell growth curves. Initial loading densities of 1-2 x 10(4) cells/fiber gave the greatest opportunity for growth in the three human cell lines tested (HCT116 colon carcinoma, NCI-H460 non-small cell carcinoma, and AG 1523 normal fibroblast). Utilizing the MTT assay, standard curves were constructed to correlate the final number of cells with optical density (OD) readings at 540 nm in order to calculate cell numbers in the fibers. Insights into the mechanism of action of cisplatin have been gained using Western blot analysis of the cell cycle markers PCNA (a protein present throughout the cell cycle) and Rb (a protein that acts as a tumor suppressor gene product) from the hollow fiber cells. In cisplatin-treated NCI-H460 cells both PCNA and Rb phosphorylation decreased, suggesting the arrest of the cells prior to the S phase. Standard therapeutic agents, cisplatin, racemic flavopiridol, cyclophosphamide and mitomycin C, were evaluated independently in the hollow fiber assay and the xenograft model. The data demonstrate that compounds active in the hollow fiber assay are also active in the xenograft.

Animals↗
PubMedDate not supplied

Regulation of gene expression and cell growth in vivo by tetracycline using the hollow fiber assay.

The hollow fiber assay presents a potentially unique tool to study the effects of regulated gene expression in cell lines that do not form tumors in vivo. The hollow fibers allow small molecules to pass freely through while keeping the cells within the fibers and segregated from host cells. OSp16.1 cells, derived from the U24 clone of the U2-OS osteogenic sarcoma tumor line, express the p16INK4a tumor suppressor under the regulation of tetracycline (tet) (Mitra J et al. Mol Cell Bio 19:3916, 1999). The in vitro induction of p16 in the OSp16.1 cell line is regulated by tet. The hollow fiber assay was used to determine whether the regulation of the p16 gene could be achieved in vivo, since these cells did not grow in the xenograft model. There were no differences in the in vivo growth pattern of U24 cells loaded into the hollow fibers with and without tet: 807% and 839% net growth, respectively. OSp16.1 cells in fibers in mice receiving 3.33 mg/kg/day tet had a 644% net growth after 21 days. There was a 194% net growth without tet. Immunoblotting of extracts prepared from the hollow fibers confirmed that p16 was induced in the absence of tet. These data demonstrate this assay is a useful tool for studying the effects of regulated gene expression in vivo.

Animals↗