Biomedical subjects

M L Cooper

Publications and source records attributed to M L Cooper.

At least 37 records · Page 2Linked to original sources

PubMed1997

Drinking and sexual experience on first dates among adolescents.

Using Steele's inhibitory conflict model (C.M. Steele & R.A. Josephs, 1990) as a framework, the present study investigated the link between alcohol use and the probability that intercourse occurred on 2 different 1st date occasions in a random sample of adolescents and young adults interviewed twice approximately 4 1/2 years apart (Ns = 1,678 and 1,780, respectively). As expected, both between-subjects/within-occasion and within-subjects/across-occasion analyses indicated that the probability of intercourse was significantly higher when the male couple member, but not his female counterpart, drank alcohol. Also consistent with Steele's model, alcohol effects on intercourse probability were found primarily among males who were highly conflicted about having intercourse on the date. Inconsistent with Steele's model, however, a similar effect was not found among highly conflicted females. Results are discussed in terms of a more general variant of Steele's model that allows for both alcohol-related disinhibition and inhibition.

Adolescent↗

PubMed1997

Mixed messages: implications of social conflict and social support within close relationships for adjustment to a stressful life event.

The authors examined the impact of women's perceptions of negative (conflict) and positive (support) exchanges with their mothers, partners, and friends before having an abortion on negative (distress) and positive (well-being) indexes of adjustment after the abortion. Preabortion conflict and support from the partner predicted postabortion adjustment in the same affective domain: Conflict uniquely predicted distress, whereas support uniquely predicted well-being. Within-source interactions were observed between support and conflict from mothers and friends. Women who perceived high support from their mothers or friends were more distressed if they also perceived them as sources of high conflict than if they perceived them as sources of low conflict. Among women who perceived their mothers or friends as nonsupportive, no relationship was observed between conflict and distress. Cross-source buffering was not observed.

Abortion, Induced↗

PubMed1997

Sexual assault history and health perceptions: seven general population studies.

This article uses data from 7 population surveys to evaluate the association of sexual assault history with health perceptions. It estimates the extent of generalizability across gender, ethnic groups, and studies; the extent to which depression accounts for or mediates the association; and whether some circumstances of assault are more strongly related to poor subjective health. Data from each of 18 subsamples of the surveys were analyzed (pooled N = 10,001; 7,550 women and 2,451 men), and results were combined by using meta-analysis. Assault was associated with poor subjective health (odds ratio [OR] = 1.63, 95% confidence interval [CI] = 1.36, 1.95) and this result was consistent regardless of gender, ethnicity, or sample. Controlling depression did not markedly change this result (OR = 1.46, 95% CI = 1.21, 1.77), indicating that depression did not account for or mediate the assault-health perceptions association. Multiple assaults and assaults by strangers or spouse were most strongly associated with poor subjective health.

Adolescent↗

PubMed1996

Opioid antagonists in the periaqueductal gray inhibit morphine and beta-endorphin analgesia elicited from the amygdala of rats.

In addition to brainstem sites of action, analgesia can be elicited following amygdala microinjections of morphine and mu-selective opioid agonists. The present study examined whether opioid analgesia elicited by either morphine or beta-endorphin in the amygdala could be altered by either the general opioid antagonist, naltrexone, the mu-selective antagonist, beta-funaltrexamine (BFNA) or the delta 2 antagonist, naltrindole isothiocyanate (Ntii) in the periaqueductal gray (PAG). Both morphine (2.5-5 micrograms) and beta-endorphin (2.5-5 micrograms) microinjected into either the baso-lateral or central nuclei of the amygdala significantly increased tail-flick latencies and jump thresholds in rats. The increases were far more pronounced on the jump test than on the tail-flick test. Placements dorsal and medial to the amygdala were ineffective. Naltrexone (1-5 micrograms) in the PAG significantly reduced both morphine (tail-flick: 70-75%; jump: 60-81%) and beta-endorphin (tail-flick: 100%; jump: 93%) analgesia elicited from the amygdala, indicating that an opioid synapse in the PAG was integral for the full expression of analgesia elicited from the amygdala by both agonists. Both BFNA (68%) and Ntii (100%) in the PAG significantly reduced morphine, but not beta-endorphin analgesia in the amygdala on the tail-flick test. Ntii in the PAG was more effective in reducing morphine (60%) and beta-endorphin (79%) analgesia in the amygdala on the jump test than BFNA (15-24%). Opioid agonist-induced analgesia in the amygdala was unaffected by opioid antagonists administered into control misplacements in the lateral mesencephalon, and the small hyperalgesia elicited by opioid antagonists in the PAG could not account for the reductions in opioid agonist effects in the amygdala. These data indicate that PAG delta 2, and to a lesser degree, mu opioid receptors are necessary for the full expression of morphine and beta-endorphin analgesia elicited from the amygdala.

Amygdala↗

PubMed1996

Enhancements in swim stress-induced hypothermia, but not analgesia, following amygdala lesions in rats.

Lesions placed in the rat amygdala significantly reduce analgesic responses induced either by conditioning or exposure to a cat. Such lesions have alternatively reduced or failed to affect unconditioned foot shock analgesia. The present study expanded the situational determinants by examining whether lesions placed in the amygdala altered analgesia or hypothermia elicited by exposure to either continuous (CCWS) or intermittent (ICWS) cold-water swims. Lesion extent included the central, medial cortico-medial, baso-lateral, baso-medial and lateral amygdaloid nuclei. Basal jump thresholds, but not core body temperatures were significantly increased by unilateral and bilateral amygdala lesions. In contrast, the hypothermic, but not the analgesic responses following CCWS and ICWS were significantly enhanced by unilateral and bilateral amygdala lesions. These data support a hypothesis suggesting that these lesions are effective in reducing those classes of analgesic responses related to the signals of stressors than to the stressors themselves.

Amygdala↗

PubMed1996

Financial stress, social support, and alcohol involvement: a longitudinal test of the buffering hypothesis in a general population survey.

This study examined whether specific facets of social support (tangible assistance, appraisal, and belonging) moderate the relationship between a specific type of stress (financial stress) and alcohol involvement (drinking to cope, heavy drinking, and alcohol problems). Data were derived from a community sample stratified by education and race. Respondents (N = 1,040) were interviewed in 1986 and 1989 and had drunk alcohol during the year preceding both interviews. Results supported the buffering influence of tangible support on the financial stress-alcohol involvement relationship. In contrast, neither appraisal nor belonging support consistently revealed a buffering pattern. These findings indicate the importance of taking into account specific components of social support when examining the relationship between specific sources of life stress and alcohol involvement.

Adaptation, Psychological↗

PubMed1996

Lane tracking software for four-color fluorescence-based electrophoretic gel images.

Software to track sample lanes automatically in four-color, fluorescence-based, electrophoretic gel images has been developed for application in large-scale DNA sequencing projects. Lanes and lane boundaries are tracked by analyzing a first difference approximation to the gradient of a vertically integrated and processed "brightness" profile. Initially lanes are located in a region of the gel image selected for good horizontal lane spacing and signal strength. The software uses models of expected lane and interlane spacing and lateral lane behavior to maintain accurate tracking on imperfect gels. In areas where intensity-based tracking is difficult, interpixel column correlation is also used to locate and define lane features. Summary statistics and compressed-in-time images are generated for user evaluation of tracking performance. The software developed has been tested successfully on gel images with degradations including significant horizontal lane motion (curving) and image artifacts, and is now in full-scale use in our sequencing projects.

Algorithms↗

PubMed1995

General, mu and kappa opioid antagonists in the nucleus accumbens alter food intake under deprivation, glucoprivic and palatable conditions.

Ventricular microinjection studies found that whereas mu (beta-funaltrexamine, B-FNA), mu1 (naloxonazine) and kappa (nor-binaltorphamine, Nor-BNI) opioid receptor antagonists, but not delta antagonists, reduce deprivation-induced intake, kappa and mu, but not mu1 or delta antagonists reduce both 2-deoxy-D-glucose (2DG) hyperphagia and sucrose intake. Since opioid agonists stimulate spontaneous food intake in the accumbens, the present study examined whether administration of either naltrexone, B-FNA or Nor-BNI in the accumbens altered intake under deprivation (24 h), glucoprivic (2DG: 500 mg/kg, i.p.) or palatable sucrose (10%) conditions. Naloxonazine's effects in the accumbens were also evaluated for deprivation-induced intake. Deprivation-induced intake was significantly decreased over 4 h by naltrexone (5-20 micrograms, 44%), B-FNA (1-4 micrograms, 55%) and Nor-BNI (4 micrograms, 31%) but not naloxonazine (10 micrograms) in the accumbens. 2DG hyperphagia was significantly decreased by naltrexone (10-20 microgram, 79%), B-FNA (1-4 micrograms, 100%) and NOR-BNI (104 micrograms, 75%) in the accumbens. Sucrose intake was significantly decreased by naltrexone (50 micrograms, 27%) and B-FNA (1-4 micrograms, 37%), but not NOR-BNI in the accumbens. These data suggest that mu receptors, and particularly the mu2 binding site in the accumbens are responsible for the opioid modulation of these forms of intake in this nucleus, and that this control may be acting upon the amount of intake per se.

Animals↗

PubMed1995

Ligation device assisting low anterior anastomosis.

UNLABELLED: The use of the circular stapler has enabled surgeons to perform very low anterior resections where previously abdominoperineal proctectomy would be performed for carcinoma of the rectum. The use of the roticulator or other linear stapler devices has facilitated these anastomoses and precluded the necessity for pursestring sutures, thereby reducing the incidence of incomplete tissue rings, which should reduce the risk of anastomotic leaks. One significant drawback to the roticulator, especially in the narrow male pelvis, is its application for very low lesions. In many cases the stapler cannot be forced deeply enough into the pelvis to allow for a sufficient margin below the tumor. PURPOSE: The purpose of this article is to report results of a prototype that applies a gasket that automatically fixes the rectum to the rod of the circular stapler. METHOD: To date the device has been used 22 times in 14 patients (8 patients had both limbs attached using the device, whereas 6 patients had only the rectal stump attached in this manner). RESULTS: All anastomoses healed without complication, all patients had complete donuts of tissue, and only two anastomoses had to be reinforced. CONCLUSION: The use of this device may facilitate stapling of very low anastomoses for carcinoma of the rectum.

Anastomosis, Surgical↗

PubMed1995

Alterations in deprivation, glucoprivic and sucrose intake following general, mu and kappa opioid antagonists in the hypothalamic paraventricular nucleus of rats.

While opioid agonists administered into the hypothalamic paraventricular nucleus increase food intake in rats, naloxone reduces deprivation-induced intake. Ventricular administration of either mu (beta-funaltrexamine) or kappa (nor-binaltorphamine) opioid antagonists reduces spontaneous, deprivation, glucoprivic and palatable intake. The present study assessed whether microinjections of either general, mu or kappa opioid antagonists into the paraventricular nucleus altered either deprivation (24 h) intake, 2-deoxy-D-glucose hyperphagia or sucrose intake in rats. Deprivation intake was significantly reduced by nor-binaltorphamine (5 micrograms, 68 nmol, 30-33%), beta-funaltrexamine (5 micrograms, 100 nmol, 26-29%) or naltrexone (10 micrograms, 260 nmol, 26%) in the paraventricular nucleus. 2-Deoxy-D-glucose hyperphagia was significantly reduced only after 2 h by naltrexone (10 micrograms, 260 nmol, 69%), norbinaltorphamine (20 micrograms, 272 nmol, 69%) or beta-funaltrexamine (20 micrograms, 400 nmol, 83%) in the paraventricular nucleus. Sucrose intake was significantly reduced by nor-binaltorphamine (5 micrograms, 68 nmol, 27-36%), naltrexone (5-10 micrograms, 130-260 nmol, 18-31%) and beta-funaltrexamine (5 micrograms, 100 nmol, 20%) in the paraventricular nucleus. These data indicate that general, mu and kappa opioid antagonists administered into the hypothalamic paraventricular nucleus produce similar patterns of effects upon different forms of food intake as did ventricular administration, implicating this nucleus as part of the circuitry underlying opioid mediation of ingestion.

Animals↗

PubMed1995

Drinking to regulate positive and negative emotions: a motivational model of alcohol use.

The present study proposed and tested a motivational model of alcohol use in which people are hypothesized to use alcohol to regulate both positive and negative emotions. Two central premises underpin this model: (a) that enhancement and coping motives for alcohol use are proximal determinants of alcohol use and abuse through which the influence of expectancies, emotions, and other individual differences are mediated and (b) that enhancement and coping motives represent phenomenologically distinct behaviors having both unique antecedents and consequences. This model was tested in 2 random samples (1 of adults, 1 of adolescents) using a combination of moderated regression and path analysis corrected for measurement error. Results revealed strong support for the hypothesized model in both samples and indicate the importance of distinguishing psychological motives for alcohol use.

Adaptation, Psychological↗

PubMed1995

A revised Alcohol Expectancy Questionnaire: factor structure confirmation, and invariance in a general population sample.

OBJECTIVE: The alcohol expectancy construct has become prominent in contemporary psychosocial approaches to understanding alcohol use and abuse. In 1980 Brown and colleagues developed the 90-item Alcohol Expectancy Questionnaire (AEQ) to assess experiences. Rohsenow modified this instrument to create the 40-item Alcohol Effects Questionnaire (AEQ-2). In the present study, we replaced the dichotomous response format of the AEQ-2 with a six-point scale to create the AEQ-3. The purpose of the study was to evaluate the AEQ-3 for factor structure confirmation and invariance across gender and race subgroups. METHOD: We administered the AEQ-3 to a large general population sample (N = 1,260). The instrument was self-administered during a structured interview. RESULTS: Confirmatory factor analyses were conducted to test a correlated eight-factor model consisting of six positive expectancies and two negative expectancies. Fit indices revealed that the eight-factor model fit the data moderately well. Furthermore, the fit of the eight-factor model was largely invariant across race and gender subgroups. Nonetheless, factor intercorrelations and modification indices revealed inadequate discriminant validity. CONCLUSIONS: Based on these findings, we cautiously recommend the AEQ-3 as a measure of alcohol expectancies. Specific recommendations and limitations are discussed regarding future use of the AEQ-3.

Adult↗

PubMed1994

Gender roles as mediators of sex differences in expressions of pathology.

This study tested the extent to which gender role attributes and gender role ideology account for sex differences in internally directed psychological distress and in externally directed deviant behavior in a random sample of 2,013 adolescents. Results indicate that gender roles substantially mediate sex differences in both types of pathology: Masculine instrumental attributes reduce internalized distress, whereas feminine expressive attributes reduce externalized behavior problems. In addition, conventional gender role attitudes were positively related to externalizing problems among male adolescents, but were unrelated to pathology among female adolescents. These associations were largely equivalent across Black and White racial groups and across age groups (13 to 19 years). Two alternative theoretical models linking gender roles and pathology are discussed.

Adolescent↗

PubMed1994

Substance use and sexual risk taking among black adolescents and white adolescents.

Analyses of data from a random sample of 1,259 sexually active adolescents revealed that substance use was associated with increased sexual risk taking on 2 occasions of intercourse (1st intercourse ever and 1st intercourse with most recent partner), even after controlling for demographic experiential, and dispositional confounders. Within-persons analyses yielded similar results, indicating that adolescents who used substances, on 1 of the 2 occasions, reported higher levels of risk taking on the occasion when substances were used than on the no-substance use occasion. However, substance use was both more common and more strongly linked to risk taking among White than Black adolescents, suggesting that White adolescents are a greater risk of negative consequences related to substance use proximal to intercourse.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Relationship of financial strain and psychosocial resources to alcohol use and abuse: the mediating role of negative affect and drinking motives.

Limited research has examined the relationship between financial strain and alcohol use and abuse. Building on affect regulation theory and recent research in the stress and alcohol literatures, this study developed and tested a model relating financial strain, social resources, personal resources, depression, and drinking to cope to alcohol use and abuse. Data were obtained from a random sample of 1,424 adults who indicated that they had drunk alcohol in the previous year. We tested and then revised our model using structural equation modeling analysis. Results supported the affect regulation model of financial strain and alcohol use and abuse. Generally, depression mediated the relationship between financial strain and drinking to cope, and drinking to cope mediated the relationship between depression and alcohol use and abuse. In addition, both gender and race moderated six of the relationships in our revised model.

Adult↗

PubMed1993

Interactions among aging, gender, and gonadectomy effects upon morphine antinociception in rats.

In addition to age-related deficits in morphine antinociception in female rats, gender and gonadectomy differences have also been observed, with male rats displaying greater magnitudes of effects than females and castrated males. Since there are little data indicating how aging, gender, and gonadectomy interact in modulating morphine antinociception, the present study evaluated alterations in this response as functions of age (6, 12, 18, and 24 months), gender, and gonadal status (intact, gonadectomized) across a dose range (1-10 mg/kg) and time course (0.5-2 h) on the tail-flick test. The maximal percentage effect (MPE) of morphine (1 mg/kg) was significantly increased in castrated males (18 months), sham females (18 and 24 months), and ovariectomized females (18 months) relative to 6-month-old groups. Increases in the MPE of morphine (1 mg/kg) occurred in sham females (24 months) relative to corresponding sham males and ovariectomized females. The MPE of morphine (2.5 mg/kg) was significantly increased in sham males (18 months) and decreased in sham females (12 months). Decreases in the MPE of morphine (2.5 mg/kg) occurred in castrated males (18 and 24 months) as well as sham (18 months) and ovariectomized (18 and 24 months) females relative to sham males. Whereas the MPE of morphine (5 mg/kg) was unchanged by these variables, the MPE of morphine (10 mg/kg) was significantly decreased in sham females (18 and 24 months) relative to females aged 6 months, as well as males and ovariectomized females aged 24 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1993

Direct comparison of a cultured composite skin substitute containing human keratinocytes and fibroblasts to an epidermal sheet graft containing human keratinocytes on athymic mice.

This study compares two techniques for making cultured skin substitutes: a composite graft made of human fibroblasts and keratinocytes on a collagen-glycosaminoglycan membrane (CG) and a cultured epidermal cell sheet graft (CEG), without a dermal component. The "take" and quality of these cultured skin substitutes were evaluated by placing them on full-thickness, excised wounds of athymic mice. These cultured skin substitutes were placed onto 2-X-2-cm wounds created on athymic mice. Mice were sacrificed at days 10, 20, and 42 with histologic sections obtained for light, electron, immunofluorescent, and immunohistochemical microscopy. "Take" was determined separately by a direct immunofluorescent stain for human leukocyte ABC antigens. There were ten mice of each graft type with at least two animals sacrificed at each time point. Results showed positive "take" for all animals. Grossly, there was little difference between the two graft types, with the CEG having occasional blister formation. By light microscopy, the CEG had a dissociation of dermis from epidermis until day 42, which was never apparent with the CG. By day 42, the CG had increased dermoepidermal interdigitations similar to rete ridges, with a mature epithelium. Neither of these findings were seen with the CEG. Immunofluorescent and immunohistochemical microscopy for type IV collagen and laminin, as well as electron microscopy, showed similar retardation of basement membrane formation with the CEG. Using this model, the composite graft had significant advantages over the epidermal sheet graft in the closure of full-thickness wounds.

Animals↗

PubMed1993

Individual differences in differentiation among alcohol expectancy domains.

Prior research indicates that alcohol-related outcome expectancies represent important etiological factors in the understanding of alcohol use/abuse. Although current multidimensional measures assess several substantively different domains of alcohol-related outcome expectancies, there is growing evidence that they may not possess adequate levels of discriminant validity. Therefore, the present study sought to examine whether reliable between-person differences exist in the ability to differentiate among alcohol expectancy domains. The focus of the study was on three sets of intrapersonal characteristics: cognitive resources, cognitive constraints, and alcohol-related experience. Data were collected via household interviews with a random sample of 1125 adults. Multiple regression analysis revealed that higher levels of cognitive resources were associated with increasing levels of differentiation among alcohol expectancy domains. Results are discussed in terms of implications for the development of new or revised multidimensional alcohol expectancy questionnaires. Directions for future research are also discussed.

Adult↗