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D C Clark

Publications and source records attributed to D C Clark.

177 records · Page 10Linked to original sources
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The relationship between academic performance and severity of depressed mood during medical school.

We employ a structural equation model to examine the relationship between academic performance and depressed mood over 4 years for a single medical school class. Academic performance measures included undergraduate gradepoint average, first- and second-year medical school gradepoint average, full Medical College Admissions Test (MCAT) and total National Boards Part I (NB) scores. Severity of depressed mood was assessed by administering the Beck Depression Inventory two times per year during the first 2 years, and once per year during the last 2 years. Overall there is little reason to think that depressive mood states compromise academic performance during the first 2 years of medical school for the class as a whole. Medical school grades had no direct impact on depressed mood, and mood had no direct impact on grades. There was a non-significant tendency for mood in the months preceding National Boards Part I to influence Board scores, which in turn influenced mood. Students with higher college gradepoint averages consistently reported fewer depressive symptoms throughout medical school. The latter result directs attention to a subgroup of medical students less susceptible to depression, or less prone to admit distress or symptoms. The non-susceptible and/or minimizing qualities of this subgroup merit further investigation.

Achievement↗
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Exactly what does the Hamilton Depression Rating Scale measure?

The purpose of this study is to evaluate empirical criticism of the psychometric properties of the Hamilton Depression Rating Scale (HDRS) by undertaking an "internal construct validity" evaluation. Individual symptom responses for the HDRS were obtained from 370 patients meeting Research Diagnostic Criteria for major depression. A multidimensional normal item response theory (IRT) model was used to assess the dimensionality of the HDRS and estimate corresponding item parameters which were then expressed as factor loadings and item thresholds. The analysis yielded a five-dimensional solution. The first dimension (depressed mood, guilt, suicide, work and interests, agitation, psychic anxiety, somatic anxiety, and loss of libido) appeared to define global depression severity. These results are consistent with other published factor analytic studies and provide further justification for thinking that the HDRS total score is a weak index of depressive syndrome severity. The findings provide a benchmark by which the adequacy of future results may be judged, because the multidimensional IRT model does not suffer from the statistical limitations that arise when applying traditional factor analytic methods to discrete symptom ratings.

Adolescent↗
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Localization of 99mTc-labeled immune splenocytes at tumor site and detection by gamma camera imaging.

Better diagnostic techniques are needed to delineate the size and location of malignant primary tumors and metastatic deposits. We are developing an in vivo tumor visualization technique utilizing 99mTc-labeled immune lymphoid cells. We have investigated the in vivo organ and tissue distribution and tumor localization of 99m sodium pertechnetate, 99mTc, reduced by SnCl2 - 2H2O and 99mTc-labeled viable immune and nonimmune lymphocytes 32 hrs after injection into tumor-bearing mice. The distribution and tumor localization of the 99mTc-labeled compounds and splenocytes within tumor-bearing mice after 32 hrs was determined by imaging with a gamma camera and was quantitated by counting the various dissected organs and tissues in a gamma counter. The gamma camera images and postmortem dissection and counting showed localization of radioactivity at several sites, including the tumor in mice injected with radiolabeled immune splenocytes whereas studies utilizing other 99mTc-labeled substances or nonimmune cells showed little or no localization of radioactivity in the tumor when compared to normal leg tissue.

Animals↗
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Alcohol use patterns of first-year medical students: I. Development of shared norms.

Freshman medical students (96% of one class; n = 116) completed questionnaires on alcohol use at orientation, and again in April (n = 106) of that same year. Quantity/frequency and self-label ratings of alcohol use were employed to define normative ranges (in ethanol oz/wk). The confidentiality of student participants was protected. Males consumed five drinks per week over the summer and dropped to four per week during school; females consumed two drinks per week over both periods. Summertime and school year consumption rates were strongly correlated. Normative ranges of drinking converged from September to April, suggesting the emerging norms were the product of social experience with classmates. Class norms described a "cutpoint" separating acceptable range from excessive drinking (more than two drinks per day). The authors conclude that reliable "community norms" for medical students could be identified, the norms evolve over time, and they can be employed to determine the boundaries of acceptable drinking for research and screening purposes.

Adult↗
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Alcohol use patterns of first-year medical students: II. Psychosocial characteristics associated with drinking level.

Psychosocial characteristics that identified first-year medical students who drank more or less alcohol than their peers were examined. Subjects were 116 freshman medical students (96% of one class) who completed questionnaires about alcohol use, mood, personality, social relationships, and parental alcohol abuse on the first day of school, and 106 (88% of the class) who responded to the same questionnaires in April of the first year. Heavier drinking students (i.e., the upper 25% of the sample) were more likely to be male and single, to have drunk heavily prior to medical school, to come from larger social networks which include fewer relatives, and to demonstrate a lower interpersonal orientation. Mood, academic performance, and parental alcohol abuse were not associated with drinking level. The heaviest drinkers in this sample appear to be precisely those individuals who are most impervious to peer or other social influences.

Achievement↗
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Child bereavement after paternal suicide.

BACKGROUND: Studies of child suicide survivors are rare and often these studies have not included direct interviews with children. OBJECTIVES: To describe the bereavement process in a sample of prepubertal children whose fathers died by suicide within the previous three years. METHODS: Sixteen prepubertal children, their mothers, and a relative or caretaker were interviewed to examine grief, trauma, and behavior within 25 months of paternal suicide. RESULTS: Reminiscing was the most frequently endorsed grief behavior. Males were more likely than females to score above the standard means for CBCL scores. PTSD scores were significantly related to parental threats of divorce and exposure to death by discovery of the body. CONCLUSIONS: The concept of grief and trauma as separate and overlapping phenomena is supported by the study findings.

Bereavement↗
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Effects of a 1% chlorhexidine gel on the cariogenic bacteria in high-risk elders: a pilot study.

Root caries in dentate elderly patients is a problem which may be controlled with chlorhexidine. The purpose of this pilot study was to establish the extent and duration of the antimicrobial effects from an intensive regimen of a 1% chlorhexidine gel in institutionalized elders who had experienced high caries activity in the previous year. Stimulated saliva samples from all subjects before treatment produced more than 105 colony forming units/milliliters of Streptococcus mutans (mean: 2.0 x 10(7); s.d.: 2.0 x 10(7)) when diluted and cultured on Mitus Salivarius-bacitracin agar for 48 hours. Findings suggest that daily treatments for 1 week with a 1% chlorhexidine gel can reduce the number of cariogenic bacteria in elderly people for approximately 3 weeks after treatment.

Aged↗
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Tooth-surface progression and reversal changes in fluoridated and no-longer-fluoridated communities over a 3-year period.

OBJECTIVE: To compare permanent tooth surface-specific progression/reversal changes between fluoridation-ended (F-E) and still-fluoridated (S-F) communities in British Columbia, Canada, over a 3-year period. METHODS: D1D2MFS examinations were contrasted for 2,964 schoolchildren in 1993/94 (grades 2, 3, 8 and 9) and 1996/97 (grades 5, 6, 11 and 12). Generalized Estimating Equation (GEE) models explored the relation between progression/reversal changes and fluoridation status, age, gender, socioeconomic status, and dietary/fluoride histories. RESULTS: Within a scenario of low levels of caries overall, few children had multiple surfaces progressing. At least one smooth surface progressed in 31.4% of subjects; at least one pit-and-fissure (PF) surface progressed in 43.1% of subjects. At least one smooth surface reverted in 89% of subjects who had reversible stages; at least one PF surface reverted in 23.8% of subjects who had reversible stages. GEE (smooth) indicated that odds ratios of progression were twice as large in the F-E site compared to the S-F site, and slightly increased in older participants and in participants exposed to more fluoride technologies. GEE (PF) also indicated that progression was slightly more common in the F-E site; more frequent snacking and lower parental educational attainment had modest associations with increased progression in PF surfaces. For the two types of surfaces, GEE models demonstrated that unerupted surfaces were less likely to progress than sound surfaces. No associations were found between reversals and independent variables. CONCLUSION: Progressions were found to be weakly linked to socio-demographic factors; baseline surface statuses were better predictors of progression. Using the current definitions for disease transitions, F-E communities had more frequent progressions than a S-F community.

Adolescent↗
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Socio-demographic features and fluoride technologies contributing to higher fluorosis scores in permanent teeth of Canadian children.

OBJECTIVE: To examine levels of fluorosis among children in two Canadian communities exposed to fluoride. BACKGROUND: One community had discontinued fluoride, the other had maintained it. Water supplies, however, were fluoridated for all the children when their esthetically important teeth were mineralized. METHODS: We examined 8,277 children to assess Thystrup-Fejerskov Index (TFI) scores. Multivariate Poisson regression models were used to identify the relationship between TFI and water fluoride status, age, gender, SES, and dietary and fluoride exposure histories (supplements, rinses, toothpaste amount, tooth brushing frequency, and tooth brushing starting age). Parent(s) completed questionnaires. RESULTS: Overall, levels of fluorosis were low to mild, with residents of the fluoridation-ended communities having marginally higher TFI scores than those of the still-fluoridated community. Females had higher TFI scores than males. Children aged 10 years or more had higher TFI scores than younger children. Consuming bottled water between birth and 6 months of age was protective. Exposure to fluoridation technologies was consistently associated with fluorosis experience. Children who began brushing with fluoride toothpaste between their first and second birthdays had higher TFI scores than those who began between their second and third birthdays, regardless of daily brushing frequency. Children who regularly used supplements had higher TFI scores than those who did not. Children with a college-educated father had higher TFI scores than those whose fathers had less education. CONCLUSIONS: Higher fluoride exposure slightly increased the likelihood that a child had a higher TFI score, especially when more fluoridation technologies were used at home.

Age Factors↗
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The challenge of a fluoridation referendum: the results of a referendum in British Columbia.

On February 15, 1992 the voters in Comox and Courtenay, British Columbia voted out fluoridation after over 20 years experience with the public health measure. This article details what brought about this unfortunate event, what transpired prior to the referendum, and discusses the outcome relative to how the campaign unfolded. The authors describe the opposition and their strategies, and how, in hindsight, the campaign might have been better managed. Not surprisingly, this loss is similar to many before it. Anti-fluoridationists are well funded and organized, and their campaign strategies create enormous challenges for public health officials.

Attitude to Health↗