Search PubMed⌕ Search

Biomedical subjects

R A Bell

Publications and source records attributed to R A Bell.

At least 55 records · Page 3Linked to original sources
PubMed1999

Abnormal urinary protein excretion in African Americans with type 2 diabetes mellitus.

The purpose of this investigation was to determine the prevalence and correlates of abnormal urinary albumin excretion and to examine the possible additive effects of cardiovascular risk factors on urinary albumin excretion in African Americans with type 2 diabetes mellitus. One hundred fifty-one African-American subjects who met WHO criteria for type 2 diabetes were included in this cross-sectional analysis. Subjects were identified through computerized medical records from a family medicine clinic and a community health center. Urinary albumin excretion ratios (UAER) were determined from overnight samples. The prevalence of abnormal urinary protein excretion was 51%. Of those with abnormal protein excretion, 36% had microalbuminuria and 15% had macroalbuminuria. Diabetes duration, waist to hip ratio, blood pressure, and total- and LDL cholesterol were significantly higher in subjects with macroalbuminuria. Regression analysis indicated that mean arterial blood pressure, diabetes duration and total cholesterol were independently associated with UAER. Mean UAER significantly increased with the addition of one or more syndrome X risk factors to pure diabetes. Our results indicate that African Americans with type 2 diabetes mellitus have a high prevalence of abnormal urinary protein excretion, which is associated with a clustering of additional cardiovascular risk factors. The fact that this increased risk was associated with hypertension indicates that screening for albuminuria in this population is essential and that a majority of African Americans with diabetes may be at risk for developing cardiovascular complications.

Albuminuria↗
PubMed1999

Advertisement-induced prescription drug requests: patients' anticipated reactions to a physician who refuses.

BACKGROUND: Drug manufacturers increasingly encourage patient prescription drug demand through the use of direct-to-consumer (DTC) advertisements. We describe patients' forecasts of their reactions if their doctor were to deny an advertisement-motivated drug request and then identify significant predictors of these reactions. METHODS: We conducted a random phone survey of 329 Sacramento adults (response rate = 69%). Key outcomes were respondents' perceived likelihood of reacting to the nonfulfillment of a prescription request by becoming disappointed, trying to persuade the physician to reconsider, seeking a prescription from a different physician, and changing physicians. We also assessed associations between the likelihood of these reactions and respondents' evaluations of their physician's communication skills; attitudes toward, assumptions about the regulation of, and past responses to DTC advertising; health status; and demographic characteristics. RESULTS: Disappointment was the most likely reaction (46%). One fourth of the respondents anticipated resorting to persuasion and seeking the prescription elsewhere, while only 15% considered terminating their relationship with their physicians. Subjects who anticipated reacting in these 4 ways reported lower satisfaction with their physicians, evaluated DTC advertising more favorably, and possessed more confidence in the government's regulation of these advertisements. CONCLUSIONS: A sizable fraction of patients believed they would react negatively if their physician refused to provide a prescription for a drug advertised in the general media. Avenues for dealing effectively with patients' advertising-induced requests for prescription drugs are needed.

Adolescent↗
PubMed1999

A taxonomy of requests by patients (TORP): a new system for understanding clinical negotiation in office practice.

BACKGROUND: The goal of our investigation was to facilitate research on clinical negotiation between patients and physicians by developing a reliable and valid classification system for patients' requests in office practice. METHODS: We developed the Taxonomy of Requests by Patients (TORP) using input from researchers, clinicians, and patient focus groups. To assess the system's reliability and validity, we applied TORP to audiotaped encounters between 139 patients and 6 northern California internists. Reliability was assessed with the kappa statistic as a measure of interrater agreement. Face validity was assessed through expert and patient judgment of the coding system. Content validity was examined by monitoring the incidence of unclassifiable requests. Construct validity was evaluated by examining the relationship between patient requests and patient health status; patient request fulfillment and patient satisfaction; and patient requests and physician perceptions of the visit. RESULTS: The 139 patients made 772 requests (619 requests for information and 153 requests for physician action). Average interrater agreement across a sample of 40 cases was 94% (kappa = 0.93; P <.001). Patients with better health status made fewer requests (r = -0.17; P = .048). Having more chronic diseases was associated with more requests for physician action (r = 0.32; P = .0002). Patients with more unfulfilled requests had lower visit satisfaction (r = -0.32; P <.001). More patient requests was also associated with physician reports of longer visit times (P = .016) and increased visit demands (P = .006). CONCLUSIONS: Our study provides evidence that TORP is a reliable and valid system for capturing and categorizing patients' requests in adult primary care. Further research is needed to confirm the system's validity, expand its applicability, and explore its usefulness as a tool for studying clinical negotiation.

California↗
PubMed1999

Probing the "active site" of diamine oxidase: structure-activity relations for histamine potentiation by O-alkylhydroxylamines on colonic epithelium.

The responses of the canine colonic epithelium to histamine are potentiated by O-alkylhydroxylamines. A study of a series of such compounds suggested that active compounds had the structure R-O-NH2, substitution of a nitrogen led to total loss of activity. The locus of the potentiation effect was traced to the inhibition of diamine oxidase. A new series of aliphatic and aromatic O-alkylhydroxylamines were synthesized to explore further the structure-activity relations of this effect. The potentiating effects of these compounds were determined by examining the changes in short circuit current (Isc) produced by histamine and from the activity of a soluble preparation of diamine oxidase. We found that 1) branched compounds are less active than their straight chain counterparts, 2) greater steric bulk of the aliphatic substituent decreased activity, 3) the presence of a double bond had no significant effect though a triple bond reduced activity, 4) longer straight chain compounds were less active than the shorter chain derivatives and 5) all benzylic compounds were less active than the straight chain aliphatics. O-1-benzyl was inactive however the meta or para oxygen substituted compounds as well as the O-(1-E-Cinnamyl) derivative were active. A current model for the action of diamine oxidase proposes a crucial role for a trihydroxyphenylalanine quinone cofactor as part of the active site together with a copper atom. Using molecular modeling based on our inhibition data we are able to define the region of space that is just beyond the reactive carbonyl of the trihydroxyphenylalanine residue at the active site of diamine oxidase. We suggest that a negatively charged species, such as an aspartate or a glutamate, resides in a trough about 7 to 8 A from the trihydroxyphenylalanine carbonyl carbon and this species aids in the strong selective binding of substrates such as putrescine and histamine.

Amine Oxidase (Copper-Containing)↗
PubMed1998

Phenylethanolamine N-methyltransferase gene expression: synergistic activation by Egr-1, AP-2 and the glucocorticoid receptor.

The gene encoding the epinephrine synthesizing enzyme, phenylethanolamine N-methyltransferase (PNMT), is transcriptionally activated by Egr-1, AP-2, and the glucocorticoid receptor (GR). Stimulation by AP-2 requires its synergistic interaction with an activated GR. The present studies show that the GR also cooperates with Egr-1 or the combination of Egr-1 and AP-2 to activate the PNMT promoter. Together Egr-1, AP-2, and the GR can induce PNMT promoter-mediated luciferase reporter gene expression beyond the sum of their independent contributions as well as synergistically activate the endogenous PNMT gene leading to marked increases in PNMT mRNA. Examination of the effects of mutation of the AP-2 or Egr-1 binding sites on PNMT promoter activation by DEX and the factor binding to the remaining intact site or by all three transcriptional activators showed changes in luciferase reporter gene expression which suggest that DNA structure may be altered thereby reducing or enhancing synergistic activation. It also appears that the -165 bp Egr-1 site may not be critical for the synergism observed between Egr-1, AP-2 and the GR. When the glucocorticoid response element (GRE) within the PNMT promoter was mutated, PNMT promoter activation by Egr-1 and DEX, AP-2 and DEX or all three showed both inhibition and enhancement, even when the GRE was completely eliminated. These observations indicate that induction of PNMT gene transcription may occur either through GR interaction with other transcriptional proteins after binding to its cognate GRE or through direct protein-protein interaction in the absence of GRE binding. While the mechanisms by which Egr-1 and the GR and Egr-1, AP-2 and the GR function cooperatively to stimulate PNMT promoter activity remain to be elucidated, this synergistic stimulation of the PNMT promoter by these factors may provide important in vivo and in vitro regulatory control of the PNMT gene.

Animals↗
PubMed1998

Antioxidant nutrient intake and diabetic retinopathy: the San Luis Valley Diabetes Study.

OBJECTIVE: Diabetic retinopathy (DR) is a major cause of visual impairment and blindness in adults. Antioxidant nutrients, such as vitamins C and E and beta-carotene, may be protective of some eye disorders, such as cataract and age-related macular degeneration, but a relationship between these nutrients and DR has yet to be defined. The purpose of this study was to examine the relation between dietary and supplement intakes of vitamins C, E, and beta-carotene and the risk of DR. DESIGN: Both cross-sectional and longitudinal data were collected from participants in the San Luis Valley Diabetes Study, including non-Hispanic white and Hispanic adults in southern Colorado. PARTICIPANTS: A total of 387 participants with type 2 diabetes completed at least 1 complete retinal examination and 24-hour dietary recall (including vitamin supplement use). MAIN OUTCOME MEASURES: Type 2 diabetes was defined according to World Health Organization criteria. DR was assessed by retinal photographs, using the Airlie House criteria to classify DR as none, background, preproliferative, or proliferative. Data for both eyes, from up to three clinic visits per participant, were used for analysis. Ordinal logistic regression analysis was used, taking advantage of multiple clinic visits by individual participants and observations from both eyes, to assess the risk for increased DR severity over time as a function of changes in intake of vitamin C, vitamin E, and beta-carotene. Six categories of intake for each nutrient (first to fourth quintiles and ninth and tenth deciles) were considered to ascertain any potential threshold effect. Analyses accounted for age, duration of diabetes, insulin use, ethnicity, glycated hemoglobin, hypertension, gender, and caloric intake. RESULTS: An increase over time in vitamin C intake from the first to ninth deciles was associated with a risk for increased severity of DR (odds ratio = 2.21, P = 0.01), although excess risk was not observed for the tenth decile or the second through fourth quintiles compared to the first quintile. Increased intake of vitamin E was associated with increased severity of DR among those not taking insulin (odds ratios = 2.69, 2.59, 3.33, 5.65, 3.79; P < 0.02, for an increase over time from the first to the second through fourth quintiles and ninth and tenth deciles, respectively). Among those taking insulin, increased intake of beta-carotene was associated with a risk for severity of DR (odds ratio = 3.31, P = 0.003, and 2.99, P = 0.002, respectively, for the ninth and tenth deciles compared to the first quintile). CONCLUSIONS: No protective effect was observed between antioxidant nutrients and DR. Depending on insulin use, there appeared to be a potential for deleterious effects of nutrient antioxidants. Further research is needed to confirm associations of nutrient antioxidant intake and DR.

Adult↗
PubMed1998

Glucocorticoid-dependent action of neural crest factor AP-2: stimulation of phenylethanolamine N-methyltransferase gene expression.

AP-2 is a vertebrate transcription factor expressed in neural crest cells and their derivative tissues, including the adrenal medulla, where epinephrine is produced. AP-2 is shown to stimulate expression of the gene encoding the epinephrine biosynthetic enzyme phenylethanolamine N-methyltransferase (PNMT). However, stimulation of the PNMT gene by AP-2 requires glucocorticoids and appears to be mediated through the interaction of AP-2 with activated type II glucocorticoid receptors. Mutation of AP-2 and/or glucocorticoid receptor binding elements within the PNMT promoter disrupts the ability of AP-2 and glucocorticoids to induce PNMT promoter activity. These findings suggest, in the case of PNMT, that AP-2 stimulates gene expression through a novel glucocorticoid-dependent mechanism.

Adrenal Medulla↗
PubMed1998

Body fat, fat distribution, and psychosocial factors among patients with Type 2 diabetes mellitus.

Diabetes, a risk factor for cardiovascular disease, requires lifestyle modifications (diet, exercise, weight loss). The relations between body mass index, waist-hip ratio (WHR), and psychosocial indicators, such as affect and stress, among 302 diabetic patients from a clinic and a neighborhood health center were analyzed. Data included stress and mood scale responses, body size (height, weight, and WHR) and potential confounders (physical activity, energy intake, and diabetes duration). In univariate analyses, body mass index was positively associated with stress and inversely associated with positive affect only in women. Multiple regression analyses indicated that stress was associated with body mass index and negative mood was associated with the WHR. The findings suggested that stress and affect may be important correlates of body fat among women with Type 2 diabetes, leading to more complications. Healthcare providers can help women with Type 2 diabetes lose weight and lower the risk of cardiovascular disease by recognizing and helping them deal with these psychosocial issues.

Adult↗
PubMed1998

Barriers to nutritional well-being for rural elders: community experts' perceptions.

Older adults use public and private services, as well as personal resources, to meet nutritional needs. In-depth interviews conducted with 73 service providers and community experts in two rural North Carolina counties were analyzed for these experts' perceptions of barriers to adequate nutrition for older adults. Perceived barriers included characteristics of the county and programs, transportation, and kin, as well as older adult medical and economic conditions, food habits, knowledge, and attitudes. The importance given each of these domains varied by respondents' area of expertise. Community experts and providers may not see the connection between their services and nutritional well-being of older adults.

Aged↗
PubMed1998

The effects of a managed care educational program on faculty and trainee knowledge, attitudes, and behavioral intentions.

PURPOSE: To assess the state of managed care knowledge and attitudes and to evaluate the effects of a two-day course on participants' knowledge, attitudes, and behavioral intentions. METHOD: In 1996, the University of California, Davis, Medical School invited all medical students, residents, faculty, and administrators to participate in one of two sessions of a two-day course on managed care. Participants in the first session were given both pre- and post-course questionnaires. Participants in the second session were given only post-course questionnaires. The questionnaires measured objective knowledge, attitudes, and behavioral intentions. Participants (other than administrators) who completed the questionnaires also received a follow-up questionnaire six months after the seminar. RESULTS: The two sessions were attended by 818 UC Davis medical students, residents, faculty, and administrators: after excluding 33 non-physician administrators, 428 completed survey packets (55%) were available for full analysis. Before the course, participants in the first session correctly answered on average only 46% of 32 questions about managed care knowledge. Course attendance was associated with significant gains in knowledge (to 67% correct, p < .001) and a marked increase in appreciation for the cost-control effectiveness of managed care (from 3.35 to 3.98 on a five-point scale, p < .001). Knowledge gains were greatest among medical students; changes in attitudes and behavioral intentions were least among residents. Among respondents to a follow-up survey, the changes were partially sustained six months later. CONCLUSION: Within this academic medical center, baseline levels of managed care knowledge were low among faculty as well as among trainees, and attitudes reflected a blend of negativism and wishful thinking. An intensive two-day educational program effectively increased knowledge and changed selected attitudes among critical academic constituencies. Other academic medical centers may wish to consider presenting similar programs in order to orient their faculties and trainees to the economic realities of the foreseeable future.

Academic Medical Centers↗
PubMed1998

Medical examiner cases associated with previously undiagnosed diabetes mellitus, North Carolina, 1994.

BACKGROUND: Approximately half of the 16 million Americans with diabetes mellitus (DM) are unaware they have the disease; the epidemiology of death from previously undiagnosed DM is unclear. We report medical examiner (ME) cases of death from DM in North Carolina in 1994 to determine the number and characteristics of these cases. METHODS: Deaths from DM ICD-9 were identified and reviewed. RESULTS: Of the 42 cases ascertained from ME records, 6 had previously undiagnosed DM, 5 had diabetes ketoacidosis, and 1 had nonketotic hyperosmolar hyperglycemia. Mean patient age at death for all cases was 42 years (range, 35 years to 57 years). Four patients felt bad at least 24 hours before death, indicating that they are not technically "sudden deaths." CONCLUSIONS: We provide a limited epidemiologic perspective of the phenomenon of death from undiagnosed DM. We suggest further investigation of mortality from previously undiagnosed diabetes.

Adolescent↗
PubMed1998

Attitudes and behavioral intentions regarding managed care: a comparison of academic and community physicians.

Physicians' attitudes toward managed care and the impact of these attitudes on behaviors that affect patient care are important factors in managed care reform. In addition, the attitudes of academic physicians may influence their willingness to reform medical education in an effort to prepare students to practice under managed care. Although it is a conventional opinion that the academic health center and its academic physicians are antagonistic toward managed care, there has not been a direct comparison of the attitudes of these physicians to those of practicing community physicians. We used a self-administered questionnaire to assess attitudes toward managed care and behavioral intentions regarding practices related to managed care; a sample of academic physicians (n = 129) was compared with a sample of community physicians (n = 307). Community physicians were less negative in their evaluations of the quality of care in a managed care environment, but no differences were identified between the two groups with regard to the cost-effectiveness, inevitability, or need to adapt to managed care. Academic specialists were more likely than academic primary care physicians to rate managed care as something to which they needed to adapt. Community physicians were less likely to report a willingness to change their referral patterns. Aggregating across practice type, we also uncovered systematic differences between primary care and specialist physicians. The data suggest that opinions about quality and cost-containment in managed care are significant correlates of intentions to change practice behaviors.

Attitude of Health Personnel↗
PubMed1998

Church-related correlates of tobacco use among Lumbee Indians in North Carolina.

BACKGROUND: Although minority populations suffer a disproportionately higher burden of tobacco-attributable morbidity and mortality, the church appears to be a promising avenue through which to pursue tobacco-cessation interventions in these communities. This report describes church-related correlates of tobacco use among the Lumbee Indians in North Carolina, a population with a high prevalence of tobacco use, strong ties to tobacco-related agriculture, and high levels of church participation. METHODS: A cross-sectional telephone survey of 400 adult Lumbee Indians was carried out in Pembroke, a town in Robeson County, NC. The questionnaire elicited information on tobacco use, demographic and social support information, knowledge and practices related to tobacco agriculture and traditional Native American tobacco use and church participation. RESULTS: Sixty-three percent of participants were church members and 82% said the church is "very important" to the Lumbee community. In bivariate analysis, church attendance over the past year correlated with age, education, gender, number of close friends and relatives, marital status and current smoking status. Church attendance was not related to current smokeless tobacco use or participation in tobacco-related agriculture. Current smokers who had not attended church in the past year smoked significantly more cigarettes per day than current smokers attending church more often. In logistic regression, participants attending church weekly or more often were 73% less likely to be current smokers (adjusted odds ratio [AOR] = 0.27, 95% confidence interval [CI] = 0.11-0.68). Among ever-smokers, participants having attended church infrequently in the past year were 79% less likely to have quit (AOR = 0.21, 95% CI = 0.07-0.65). Having participated in tobacco agriculture as a child predicted current Christian views on tobacco use. DISCUSSION: Tobacco use, common among Lumbee adults, correlates with a variety of demographic and social support variables. In addition, these data are the first to uncover a dose-response relationship between church attendance and number of cigarettes smoked per day by current smokers, and the relationship between childhood participation in tobacco agriculture and Christian views on tobacco use. Our results should be useful in designing a church-based tobacco-cessation intervention among Lumbee Indians.

Adult↗
PubMed1997

Naturally occurring analogs of Lymantria testis ecdysiotropin, a gonadotropin isolated from brains of Lymantria dispar pupae.

Lymantria testis ecdysiotropin (LTE) was isolated from the most prominent peptide peak corresponding to an active fraction obtained by high pressure liquid chromatographic (HPLC) separation of a homogenate of 13,000 Lymantria dispar pupal brains. In this work we examined the other active fractions from this separation as well as a second HPLC separation of an additional 2,300 pupal brains. Bioassay of the ecdysteroidogenic effects of each peak on L. dispar testes allowed detection of 20 peptide peaks with testis ecdysiotropic activity in addition to LTE. Of these, ten peptides were purified and sequenced. All of them were comparable to LTE in molecular weight. The amino acid sequences of five of the peptides were similar enough to LTE to be considered to be members of an LTE family. However, the other five peptides had no significant homology with LTE or with each other. A BLAST database search indicated LTE family homology with portions of inhibitory peptides such as those inhibiting cytolysis. In contrast, non-LTE ecdysiotropic peptides, in which undetermined residues designated X were assumed to be cysteine, were strikingly homologous to portions of vertebrate and invertebrate zinc finger peptides and to vertebrate and invertebrate virus proteins.

Amino Acid Sequence↗
PubMed1997

An epidemiologic review of dietary intake studies among American Indians and Alaska Natives: implications for heart disease and cancer risk.

PURPOSE: Dietary factors play an important role in the occurrence of heart disease and cancer. While American Indians and Alaska Natives (AIANs) have unique heart disease and cancer mortality profiles, little is known about the effect of diet on heart disease and cancer risk in these populations. This paper reviews existing nutritional intake data from adult AIANs, and considers the potential impact of diet on heart disease and cancer in these communities. METHODS: A review of the literature was conducted using the Medline database system and other reference materials. Studies documenting nutrient intakes only were included in this review. Studies were limited to those among healthy, non-pregnant adults. RESULTS: A total of twelve reports from 1959 to 1996 were found. Sample sizes for the studies ranged from 20 to 575 subjects. Most studies were done among women, and a variety of nutritional assessment techniques (24 hour recall, food frequency questionnaire, multiple-day food record) were used. Most studies also had limited nutrient intake data, especially for dietary fiber and vitamin E. The majority of studies reported moderately high intakes of fat and saturated fat, and low intakes of polyunsaturated fat and fiber. CONCLUSIONS: Based on the limited data, diet may play an important role in the heterogeneity of heart disease and cancer mortality in AIAN communities. More research is needed to assess the impact of diet on heart disease and cancer risk, including more longitudinal data, and data to assess the validity and reliability of traditional methods of dietary assessment.

Adult↗
PubMed1997

Prevalence and predictors of tobacco use among Lumbee Indian women in Robeson County, North Carolina.

Tobacco use among some Native American tribes is high compared to the overall US population. Little is known, however, about tobacco use among Native Americans in North Carolina, a state with strong economic ties to tobacco. To assess the epidemiology of tobacco use in this population, data from the North Carolina Native American Cervical Cancer Project was reviewed. Nine hundred eighty-two Lumbee Indian women in Robeson County provided general demographic information as well as information on cancer risk knowledge, attitudes and behaviors during the 5-year study. Women were selected from the community using a random sample of 5200 persons from the tribal roll of approximately 40,000 persons. 20.6% of women were current smokeless tobacco users, while 23.7% were current smokers. Demographic and social support predictors were unique for the different types of tobacco use. Cigarette smoking was associated with younger age, higher education, excellent or good self-reported health, having a recent physical exam, separated or divorced marital status, low church participation, and alcohol consumption. Conversely, use of smokeless tobacco was associated with older age, lower education level, fair or poor self-reported health, widowed marital status, and having a high number of friends. These data show a high prevalence of smokeless tobacco use among women in this population, and a contrast in the predictors of tobacco use by source. Intervention programs for tobacco use cessation should be sensitive to these differences.

Adult↗
PubMed1997

Vitamin E and breast cancer: a review.

Breast cancer is a major health problem in America, accounting for almost one-third of cancer-related deaths in women. The prevention of breast cancer through dietary modification is an active area of clinical and epidemiologic research. It has been proposed that the dietary supplementation of vitamin E, a lipid-soluble antioxidant, may reduce a woman's risk of developing breast cancer. In animal models, vitamin E has decreased the incidence of carcinogen-induced mammary tumors. Intake and serum levels of vitamin E and their relation to breast cancer have been evaluated in epidemiologic studies. Results of epidemiologic studies, however, have been conflicting. In this review, we examine the evidence that is available pertaining to the relationship between vitamin E and breast cancer. Although epidemiologic study results have been inconsistent, further study of this nontoxic vitamin is warranted. Particular attention should be paid to the interactions of other antioxidants with vitamin E and to the duration and timing (pre- vs. postmenopausal) of vitamin E use in determining its preventive utility in breast cancer.

Adult↗