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Biomedical subjects

S G West

Publications and source records attributed to S G West.

At least 19 recordsLinked to original sources
PubMed2001

Fine mapping and genetic heterogeneity in the pure form of autosomal dominant familial spastic paraplegia.

We evaluated seven families segregating pure, autosomal dominant familial spastic paraplegia (SPG) for linkage to four recently identified SPG loci on chromosomes 2q (1), 8q (2), 12q (3), and 19q (4). These families were previously shown to be unlinked to SPG loci on chromosomes 2p, 14q, and 15q. Two families demonstrated linkage to the new loci. One family (family 3) showed significant evidence for linkage to chromosome 12q, peaking at D12S1691 (maximum lod = 3.22). Haplotype analysis of family 3 did not identify any recombinants among affected individuals in the 12q candidate region. Family 5 yielded a peak lod score of 2.02 at marker D19S868 and excluded linkage to other known SPG loci. Haplotype analysis of family 5 revealed several cross-overs in affected individuals, thereby potentially narrowing the SPG12 candidate region to a 5-cM region between markers D19S868 and D19S220. Three of the families definitively excluded all four loci examined, providing evidence for further genetic heterogeneity of pure, autosomal dominant SPG. In conclusion, these data confirm the presence of SPG10 (chromosome 12), potentially reduce the minimum candidate region for SPG12 (chromosome 19q), and suggest there is at least one additional autosomal dominant SPG locus.

Chromosome Mapping↗
PubMed2001

Transdermal estrogen reduces vascular resistance and serum cholesterol in postmenopausal women.

OBJECTIVE: Our aim was to compare the effects of transdermal versus oral estrogens on vascular resistance index, mean arterial pressure, serum lipid concentrations, norepinephrine, and left ventricular structure. STUDY DESIGN: Ten postmenopausal women received transdermal estradiol (0.05 mg/d) plus cyclic oral progesterone for 6 months. Responses were compared with those of 23 women receiving oral conjugated estrogens (0.625 mg/d) plus cyclic progesterone and with those of 9 subjects receiving placebo in a concurrent randomized trial. We assessed the vascular resistance index and the mean arterial pressure at rest and during behavioral stressors. RESULTS: Oral and transdermal estrogen significantly decreased the vascular resistance index, mean arterial pressure, norepinephrine, and total and low-density lipoprotein cholesterol to a similar extent. Changes in the vascular resistance index and mean arterial pressure were equally evident at rest and during stress. Although both treatments reduced left ventricular mass (-4% to -6%) and relative wall thickness (-3% to -5%), these changes were not statistically significant. CONCLUSIONS: Equivalent reductions in vascular resistance index, norepinephrine, mean arterial pressure, and cholesterol were observed with transdermal and oral estrogens. Future studies comparing novel hormone regimens with oral hormone replacement therapy should include multiple risk markers to allow better assessment of their potential impact on coronary artery health.

Administration, Cutaneous↗
PubMed2001

Hormone replacement improves hemodynamic profile and left ventricular geometry in hypertensive and normotensive postmenopausal women.

BACKGROUND: Postmenopausal estrogen replacement, with or without progestins, has been related to lower cardiovascular risks. OBJECTIVE: We investigated whether the actions of estrogen on vascular resistance contribute to this cardioprotective effect. DESIGN AND METHODS: In a 6-month double-blind study, pre- and post-treatment blood pressure, cardiac index, total vascular resistance index and plasma catecholamine responses during baseline and mental stressors were compared in 69 women (including 19 with mild hypertension but no history of heart disease). Women were randomized to receive either conjugated estrogens alone, estrogens plus medroxyprogesterone, or placebo. RESULTS: Both groups on active hormone replacement showed similar decreases in vascular resistance and modest blood pressure reductions, which differed from the unchanged responses of those on placebo (P< 0.05) after 3 and 6 months of treatment. Hypertensive women showed greater reductions in vascular resistance than normotensives (P< 0.05) and their blood pressure reductions tended to be larger. Women receiving hormone replacement showed increased stroke volume and cardiac index at 6 months, particularly among hypertensives and those receiving medroxyprogesterone (P < 0.05). Hormone replacement was also related to decreases in plasma norepinephrine. Finally, in 33 women receiving hormone replacement, significant 5 and 3% decreases in echocardiographic measures of left ventricular mass index and relative wall thickness were evident at 6 months (P < 0.05), while 20 placebo-treated women showed no reliable echocardiographic improvements (P= NS). CONCLUSIONS: These findings suggest that estrogen-mediated reductions in hemodynamic load on the heart may contribute to the reduced risk of cardiovascular events in relatively healthy postmenopausal women who use hormone replacement.

Adult↗
PubMed2000

Postmenopausal smokers show reduced hemodynamic benefit from oral hormone replacement.

With use of a randomized, placebo-controlled trial, 62 healthy, postmenopausal smokers and nonsmokers were tested for resting and stress-induced hemodynamic variables before and after 6 months of treatment with either oral hormone replacement therapy or placebo. Smokers had significantly less reduction in both resting and stress-induced vascular resistance and blood pressure after treatment with oral hormone replacement therapy than nonsmokers.

Blood Pressure↗
PubMed2000

Personality coherence: moderating self--other profile agreement and profile consensus.

Traditional research on moderator variables in personality has focused on measures of relative consistency. In contrast, using Goldberg's (1992) adjectives representing the Big Five personality traits, the authors examined the applicability of moderator variables to measures of personality coherence. The authors considered 3 traditional moderator variables (interitem variability, construct similarity, and scalability) and one new moderator variable: the temporal stability of response patterns. Across 2 studies, individuals with temporally stable response patterns had higher levels of personality coherence, as measured by self-other profile agreement and informant profile consensus, than did individuals with less temporally stable patterns. By comparison, the normatively based moderator variables did not moderate self-other profile agreement and informant profile consensus. The implications for personality structure and coherence are discussed.

Adolescent↗
PubMed2000

Putting the individual back into individual growth curves.

Scaling of time (age) in latent growth curve (LGC) models has important implications for studies of development. When participants begin a study at different ages, sample means and covariance-based structural equation modeling (SEM) approaches produce biased estimates of the variance of the intercept and the covariance between the Intercept and Slope factors. However, individual data vector-based SEM approaches produce proper estimates of these parameters that are identical to those produced by multilevel modeling (MLM). Scaling of the time variable also raises issues regarding the interpretation of within- and between-persons effects of time that parallel those associated with centering of predictor variables in MLM. A numerical example is used to illustrate these issues, and an Mx script for fitting individual data vector-based LGC models is provided.

Adolescent↗
PubMed2000

Stable pessimistic attributions interact with socioeconomic status to influence blood pressure and vulnerability to hypertension.

We investigated the relationship of pessimistic attributional style (specifically, stable attributions for negative events) and socioeconomic status (SES) to cardiovascular and catecholamine profiles in a biracial sample of 37 postmenopausal women (aged 39-64 years) not taking hormone replacement therapy (HRT). Blood pressure (BP) variation in response to the demands of daily life was assessed by 24-hour ambulatory monitoring on a typical workday. Subjects were classified into groups by stable pessimistic attributions (high vs. low pessimism) and by SES (high vs. low). Significant SES x pessimism interactions were found. Low SES/high pessimism women demonstrated higher systolic BP (SBP) during the day, evening, and sleep periods of 24-hour ambulatory monitoring compared with the other three groups. A greater proportion of this group was in the hypertensive range (> or = 140/90 mm Hg) compared with the other groups (57% vs. 8%-29%). Low SES/high pessimism women also reported reduced available social support compared with the other three groups.

Adult↗
PubMed2000

The additive and interactive effects of parenting and temperament in predicting adjustment problems of children of divorce.

Investigated the interaction between parenting and temperament in predicting adjustment problems in children of divorce. The study utilized a sample of 231 mothers and children, 9 to 12 years old, who had experienced divorce within the previous 2 years. Both mothers' and children's reports on parenting, temperament, and adjustment variables were obtained and combined to create cross-reporter measures of the variables. Parenting and temperament were directly and independently related to outcomes consistent with an additive model of their effects. Significant interactions indicated that parental rejection was more strongly related to adjustment problems for children low in positive emotionality, and inconsistent discipline was more strongly related to adjustment problems for children high in impulsivity. These findings suggest that children who are high in impulsivity may be at greater risk for developing problems, whereas positive emotionality may operate as a protective factor, decreasing the risk of adjustment problems in response to negative parenting.

Adaptation, Psychological↗
PubMed2000

An experimental evaluation of theory-based mother and mother-child programs for children of divorce.

This study evaluated the efficacy of 2 theory-based preventive interventions for divorced families: a program for mothers and a dual component mother-child program. The mother program targeted mother-child relationship quality, discipline, interparental conflict, and the father-child relationship. The child program targeted active coping, avoidant coping, appraisals of divorce stressors, and mother-child relationship quality. Families with a 9- to 12-year-old child (N = 240) were randomly assigned to the mother, dual-component, or self-study program. Postintervention comparisons showed significant positive program effects of the mother program versus self-study condition on relationship quality, discipline, attitude toward father-child contact, and adjustment problems. For several outcomes, more positive effects occurred in families with poorer initial functioning. Program effects on externalizing problems were maintained at 6-month follow-up. A few additive effects of the dual-component program occurred for the putative mediators; none occurred for adjustment problems.

Adaptation, Psychological↗
PubMed1999

Confirmation of linkage of hereditary partial lipodystrophy to chromosome 1q21-22.

Familial lipodystrophy is a genetically heterogeneous set of disorders characterized by a total or partial absence of subcutaneous fat, diabetes mellitus or impaired glucose tolerance, hyperlipidemia, and hypermetabolism [Senior and Gellis, 1964]. One subtype, familial partial lipodystrophy Dunnigan (FPLD), is a rare autosomal dominant trait that results in an gradual loss of subcutaneous fat in the lower trunk and limbs, Type V hyperlipoproteinemia, hypertriglyceridemia, and insulin-resistant diabetes. Previous reports of this condition have been limited to case reports or very small families. Recently, Peters et al. reported on linkage of five families of Western European descent to a 5.3 cM region on chromosome 1q21-22 between the flanking markers D1S305 and D1S1600 [Peters et al., 1998: Nat Genet 18:292-295]. We performed linkage and haplotype analysis using highly polymorphic, microsatellite markers on a large, multigeneration Caucasian kindred of German ancestry. The maximum two-point lod score achieved was 4.96 at theta(max) = 0 for marker D1S2721. Multipoint analysis gave an overall maximum lod score of 6.27 near marker D1S2721. The results of the haplotype analysis support the minimal candidate region as reported by Peters et al.

Adult↗
PubMed1999

Emotionality and self-regulation, threat appraisal, and coping in children of divorce.

A model of the effects of children's temperament (negative and positive emotionality, impulsivity and attention focusing) on post-divorce threat appraisals, coping (active and avoidant), and psychological symptoms (depression and conduct problems) was investigated. The study utilized a sample of 223 mothers and children (ages 9 to 12 years) who had experienced divorce within the last two years. Evidence was found of direct effects of child-report negative emotionality on children's threat perceptions and of child-report positive emotionality and impulsivity on children's coping. Indirect effects of negative emotionality on active and avoidant coping through threat appraisal were found. Direct effects of the temperament variables on symptoms were also found. Cross group analyses indicated that the models were robust to age differences, but gender differences were found in the relation between negative emotionality and depression. The results of this study indicate that temperament and threat appraisals are important predictors of children's post-divorce symptoms, and that temperament is a predictor of children's appraisal and coping process.

Adaptation, Psychological↗
PubMed1999

Potassium supplementation induces beneficial cardiovascular changes during rest and stress in salt sensitive individuals.

The typical American diet includes high salt and low potassium, a pattern linked to elevated blood pressure (BP) in cross-cultural studies. This study compared resting and stress cardiovascular responses on a high salt, low potassium diet to those observed during 2 interventions: salt restriction and potassium supplementation. Forty-seven percent of the primarily normotensive sample (n = 67 adults) were salt sensitive, showing a decrease in mean arterial pressure > or = 5 mmHg during low salt and equivalent reductions during high potassium. The equivalent benefits of the interventions were maintained, but not enhanced, during exposure to behavioral stress (i.e., no effect on reactivity). Salt resistants (SRs) exhibited no change in resting or stress BP across the diets. High salt increased cardiac index in both groups, whereas vascular tone was decreased only in the SR group. High potassium produced hemodynamic benefits similar to low salt, even with continued high salt intake.

Adult↗
PubMed1999

High stress responsivity predicts later blood pressure only in combination with positive family history and high life stress.

High cardiovascular responsivity to stressors has not consistently improved prediction of later blood pressure increases beyond the predictive effects of baseline pressure. Animal models suggest that genetic susceptibility to hypertension and frequent stress exposure are important modulating factors in stress-related hypertension. Thus in 103 men originally tested at age 18 to 22 years and reassessed 10 years later, interactive effects of genetic susceptibility (defined as 1 or more hypertensive parents) with high stress responsivity (defined as top 25% on the basis of blood pressure and cardiac responses during both reaction time and cold pressor tasks) were examined in relation to follow-up systolic and diastolic levels and to change in blood pressure status from normal (diastolic<80 mm Hg) to marginally elevated (diastolic 85 to 95 mm Hg). Men with the combination of high stress response and hypertensive parents demonstrated higher systolic (P<0.05) and diastolic levels (P<0.05) at follow-up, and they showed a 7-fold increase (7.5, 95% confidence intervals 2.3, 24.3; P<0.001) in relative risk of change in blood pressure status versus men with no family history and a 3-fold increase (3.8, confidence intervals 1.5, 9.6; P<0.004) versus less stress-responsive men who also had hypertensive parents. In 65 men who also provided ratings of daily stress, family historyxstress responsivityxdaily stress interactions were significant in predicting follow-up systolic and diastolic levels (P<0.006 and 0.03, respectively), with highest pressure levels seen when high life stress was reported by high stress responders and/or men with hypertensive parents. In conclusion, results suggest that stress responsivity as a long-term predictor is modulated by both genetic and environmental factors.

Adult↗
PubMed1999

Methodological issues in evaluating Rorschach validity: a comment on Burns and Viglione (1996), Weiner (1996), and Ganellen (1996)

The old controversy regarding the Rorschach Inkblot Test has recently revived. The present article suggests that the debate will be most productive if careful attention is paid to methodological issues. Three recent examples illustrate how incorrect conclusions regarding Rorschach validity may occur if methodological issues are not evaluated carefully. The present article examines (a) Burns and Viglione s (1996) conclusion that the Rorschach Human Experience Variable (HEV) is a predictor of interpersonal relatedness among adults; (b) Weiner s (1996) conclusion that the D score and Morbid Responses (MOR) are valid measures of experienced distress in Posttraumatic Stress Disorder (PTSD); and (c) Ganellen s (1996a, 1996b) conclusion that the Rorschach Depression Index (DEPI) and the Minnesota Multiphasic Personality Inventory (MMPI) are comparable in their power to identify diagnoses of depression.

Adult↗
PubMed1998

Magnetic resonance imaging abnormalities and cognitive deficits in systemic lupus erythematosus patients without overt central nervous system disease.

OBJECTIVE: To investigate cerebral magnetic resonance imaging (MRI) abnormalities in relation to cognitive functioning in systemic lupus erythematosus (SLE) patients without a history of central nervous system (CNS) disease. METHODS: Ventricle-to-brain ratios (VBRs) and the total number of white matter hyperintensities (WMHIs) were computed in 20 female patients with non-CNS SLE using established MRI computer-generated quantification procedures. Comprehensive neuropsychological test scores across 8 domains were also obtained. RESULTS: A mean VBR of 2.83% (SD = 0.7) occurred in the non-CNS SLE patients compared with a VBR of 1.36% in a normative sample. The average number of WMHIs was 4.95 (SD = 6.0). Using a combined rating scale (VBR > 2.25%, WMHIs > 5), 7 of 20 MRI scans (35%) were classified as abnormal. Increased VBRs and larger numbers of WMHIs showed a trend association with longer duration of SLE. Thirty-five percent of the non-CNS SLE patients demonstrated neuropsychological deficits. No significant correlations were found between the VBR, total WMHIs, and cognitive scores. Comparisons of cognitively impaired and nonimpaired patients with non-CNS SLE revealed no significant differences across clinical characteristics or MRI values. CONCLUSION: Quantified MRI analyses indicated atypical brain structure and an increased number of WMHIs in a subset of non-CNS SLE patients. However, these MRI abnormalities were not associated with functional abnormalities determined by comprehensive neuropsychological testing. Therefore, MRI analyses are not likely to provide additional clinical information on cognitively impaired SLE patients who have no other evidence of CNS involvement.

Adult↗
PubMed1998

Postexercise vasodilatation reduces diastolic blood pressure responses to stress.

Regular physical exercise is known to reduce cardiovascular risk. We examined the effects of a single bout of moderate bicycle exercise on hemodynamic measures at rest and in response to the foot cold pressor (CP) and mental arithmetic (MA). Sedentary males and females (N = 32) were tested twice, following 20 minutes of moderate exercise (exercise day) versus 20 minutes of quiet rest (control day). Although resting blood pressure was no lower 20 minutes after exercise relative to the same time point on the control day, diastolic blood pressure responses to CP (p = .05) and MA (p = .06) were attenuated on the exercise day. Furthermore, recovery from moderate exercise versus control rest was also associated with reduced vascular resistance index (VRI) at rest and during exposure to both stressors (p's < or = .02). VRI reductions were largest in subjects with elevated vascular tone on the control day and were accompanied by increases in heart rate throughout the postexercise period (p's < or = .004) and higher cardiac index during exercise recovery and in response to CP (p's < or = .05). Thus, the cardiovascular benefit of exercise may in part be due to reduced VRI and attenuated cardiovascular responses to stress during the acute postexercise period.

Adult↗