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Biomedical subjects

D W Baker

Publications and source records attributed to D W Baker.

At least 19 recordsLinked to original sources
PubMed2005

Juvenile atlantic and shortnose sturgeons (family: Acipenseridae) have different hematological responses to acute environmental hypoxia.

Experiments were conducted to determine the behavioral and physiological responses to acute hypoxic challenges in Atlantic (Acipenser oxyrinchus) and shortnose (Acipenser brevirostrum) sturgeons. We measured the ventilatory rate following a 45-mmHg hypoxic challenge, as well as a variety of hematological parameters, including O2 transport and hormonal, ionic, and metabolic variables, following a 1-h exposure to either 75- or 30-mmHg hypoxic challenges. Compared to fish in normoxic conditions (Pwo2 150 mmHg), juveniles of both species increased their ventilatory rate by approximately 40% when exposed to a 1-h challenge at 45 mmHg Pwo2. Hematological variables (e.g., hematocrit, hemoglobin, and Na+ and Cl- levels) did not change substantially following a 1-h challenge at 75 mmHg Pwo2. Conversely, a severe hypoxic challenge of 30 mmHg caused changes in several hematological variables (e.g., whole blood glucose and plasma cortisol and lactate levels). Most of these hematological parameters returned to prehypoxic levels within 2 h. Severe environmental hypoxia elicited the same basic pattern of response in both species; however, maximal plasma lactate levels were higher in Atlantic sturgeons, and maximal cortisol levels were higher in shortnose sturgeons. Whether these species differences are related to dissimilar hypoxia-tolerance, ecological, and/or endocrinological characteristics between these two species is not entirely clear.

Analysis of Variance↗
PubMed2003

The effects of trace metal exposure on agonistic encounters in juvenile rainbow trout, Oncorhynchus mykiss.

The effects of five trace metals, copper, cadmium, nickel, zinc and lead (presented as soluble salts) on the ability of juvenile rainbow trout to form social relationships were investigated. Comparable concentrations of the five metals in relation to their acute 96 h LC50s (concentration at which population mortality=50% at 96 h) were used (i.e. 15% of the 96 h LC50) and water quality parameters (hardness=120 mg l(-1) as CaCO(3), pH 8; DOC=3 mg l(-1)) were kept constant throughout. In the first experiment, trout exposed to sublethal concentrations of cadmium for 24 h displayed significantly lower numbers of aggressive attacks during pair-wise agonistic encounters than fish paired in the copper, nickel, zinc, lead and control water. In a second experiment, fish were exposed to the same concentration of metal for 24 h, and then returned to normal water for 24 h. When these metal pre-exposed fish were paired with non-exposed fish only cadmium pre-exposure had a significant effect on social interaction. All of the cadmium pre-exposed fish became subordinate when paired with non-exposed fish, whereas the probability of a fish pre-exposed to copper, nickel, zinc or lead becoming subordinate did not significantly differ from random. Therefore, at around 15% of the 96 h LC50, different metals exert different effects on the social behaviour of fish, suggesting potential implications for social structure and population stability.

Aggression↗
PubMed2003

The effect of pneumonia on mortality among patients hospitalized for acute stroke.

OBJECTIVE: To determine the effect of pneumonia on 30-day mortality in patients hospitalized for acute stroke. METHODS: Subjects in the initial cohort were 14,293 Medicare patients admitted for stroke to 29 greater Cleveland hospitals between 1991 and 1997. The relative risk (RR) of pneumonia for 30-day mortality was determined in a final cohort (n = 11,286) that excluded patients dying or having a do not resuscitate order within 3 days of admission. Clinical data were obtained from chart abstraction and were merged with Medicare Provider Analysis and Review files to obtain deaths within 30 days. A predicted-mortality model (c-statistic = 0.78) and propensity score for pneumonia (c-statistic = 0.83) were used for risk adjustment in logistic regression analyses. RESULTS: Pneumonia was identified in 6.9% (n = 985) of all patients and in 5.6% (n = 635) of the final cohort. The rates of pneumonia were higher in patients with greater stroke severity and features indicating general frailty. Unadjusted 30-day mortality rates were six times higher for patients with pneumonia than for those without (26.9% vs 4.4%, p < 0.001). After adjusting for admission severity and propensity for pneumonia, RR of pneumonia for 30-day death was 2.99 (95% CI 2.44 to 3.66), and population attributable risk was 10.0%. CONCLUSION: In this large community-wide study of stroke outcomes, pneumonia conferred a threefold increased risk of 30-day death, adding impetus to efforts to identify and reduce the risk of pneumonia in patients with stroke.

Acute Disease↗
PubMed2002

Health literacy and performance on the Mini-Mental State Examination.

The objectives of the study were to determine the relationship between functional health literacy and performance on the Mini-Mental State Examination (MMSE). New Medicare managed-care enrollees aged 65 years and older, living independently in the community in four US cities (Cleveland, Houston, Tampa, and Fort Lauderdale/Miami), were eligible to participate. In-home interviews were conducted to determine demographics and health status, and interviewers then administered the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the MMSE. We then determined the relationship between functional health literacy and the MMSE, including total scores, subscale scores (orientation to time, orientation to place, registration, attention and calculation, recall, language, and visual construction), and individual items. Functional health literacy was linearly related to the total MMSE score across the entire range of S-TOFHLA scores (R(2) = 0.39, p < 0.001). This relationship between health literacy and MMSE was consistent across all MMSE subscales and individual items. Adjustment for chronic conditions and self-reported overall health did not change the relationship between health literacy and MMSE score. Health literacy was related to MMSE performance even for subscales of the MMSE that were not postulated to be directly dependent on reading ability or education (e.g. delayed recall). These results suggest that the lower MMSE scores for patients with low health literacy are only partly due to 'test bias' and also result from true differences in cognitive functioning. 'Adjusting' MMSE scores for an individual's functional health literacy may be inappropriate because it may mask true differences in cognitive functioning.

Aged↗
PubMed2001

ACC/AHA Guidelines for the Evaluation and Management of Chronic Heart Failure in the Adult: Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1995 Guidelines for the Evaluation and Management of Heart Failure): Developed in Collaboration With the International Society for Heart and Lung Transplantation; Endorsed by the Heart Failure Society of America.

Explore the source record for details and available documents.

Adult↗
PubMed2001

Lack of health insurance and decline in overall health in late middle age.

BACKGROUND: The number of adults in their 50s and 60s in the United States who do not have health insurance is increasing. This group may be particularly vulnerable to the ill effects of being uninsured. METHODS: We conducted a prospective cohort study using files from the Health and Retirement Study, a national survey of adults who were 51 to 61 years old in 1992. We determined the risks of a major decline in overall health and of the development of new physical difficulties between 1992 and 1996 for participants who were continuously uninsured (uninsured in 1992 and in 1994), those who were intermittently uninsured (uninsured either in 1992 or in 1994), and those who were continuously insured. We used logistic regression to determine the independent effects of being uninsured on health outcomes after adjustment for base-line sociodemographic factors, preexisting medical conditions, and types of health-related behavior such as smoking and alcohol use. RESULTS: We analyzed data for 7577 participants. The 717 continuously uninsured participants and the 825 intermittently uninsured participants were more likely than the 6035 continuously insured participants to have a major decline in overall health between 1992 and 1996 (21.6 percent, 16.1 percent, and 8.3 percent of the three groups, respectively; P<0.001 for both comparisons). According to a multivariate analysis, the adjusted relative risk of a major decline in overall health was 1.63 (95 percent confidence interval, 1.26 to 2.08) for continuously uninsured participants and 1.41 (95 percent confidence interval, 1.11 to 1.78) for intermittently uninsured participants, as compared with continuously insured participants. A new difficulty in walking or climbing stairs was also more likely to develop in the continuously or intermittently uninsured participants than in the continuously insured participants (28.8 percent, 26.4 percent, and 17.1 percent of the three groups, respectively; P<0.001 for both comparisons). The adjusted relative risk of such a new physical difficulty was 1.23 (95 percent confidence interval, 1.02 to 1.47) for the continuously uninsured participants and 1.26 (95 percent confidence interval, 1.01 to 1.54) for the intermittently uninsured participants. CONCLUSIONS: The lack of health insurance is associated with an increased risk of a decline in overall health among adults 51 to 61 years old.

Activities of Daily Living↗
PubMed2001

Does physician gender affect satisfaction of men and women visiting the emergency department?

OBJECTIVE: To assess the association of physician gender with patient ratings of physician care. DESIGN: Interviewer-administered survey and follow-up interviews 1 week after emergency department (ED) visit. SETTING: Public hospital ED. PATIENTS/PARTICIPANTS: English- and Spanish-speaking adults presenting for care of nonemergent problems; of 852 patients interviewed in the ED who were eligible for follow-up, 727 (85%) completed a second interview. MEASUREMENTS AND MAIN RESULTS: We conducted separate ordered logistic regressions for women and men to determine the unique association of physician gender with patient ratings of 5 interpersonal aspects of care, their trust of the physician, and their overall ratings of the physician, controlling for patient age, health status, language and interpreter status, literacy level, and expected satisfaction. Female patients trusted female physicians more (P =.003) than male physicians and rated female physicians more positively on the amount of time spent (P =.01), on concern shown (P =.04), and overall (P =.03). Differences in ratings by female patients of male and female physicians in terms of friendliness (P =.13), respect shown (P =.74), and the extent to which the physician made them feel comfortable (P =.10) did not differ significantly. Male patients rated male and female physicians similarly on all dimensions of care (overall, P =.74; friendliness, P =.75; time spent, P =.30; concern shown, P =.62; making them feel comfortable, P =.75; respect shown, P =.13; trust, P =.92). CONCLUSIONS: Having a female physician was positively associated with women's satisfaction, but physician gender was not associated with men's satisfaction. Further studies are needed to identify reasons for physician gender differences in interpersonal care delivered to women.

Adult↗
PubMed2001

Is the P25L a "real" VHL mutation?

BACKGROUND: The von Hippel-Lindau (VHL) gene has two translational initiation sites separated by 53 codons. Both proteins have been detected in cells and have equivalent activity. A mutation in the first 53 codons of the open reading frame has no effect on the structure of the smaller protein. As expected, the vast majority of VHL mutations are downstream of the second initiation site and alter both proteins. However, several candidate mutations have been found in the first 53 codons, including a substitution of leucine for proline at position 25 (P25L) of the larger protein. METHODS AND RESULTS: DNA sequence analysis showed two VHL gene mutations, P25L and P86R, in an individual with a clinical diagnosis of VHL disease. Both mutations have been reported previously. P25L alters only the upstream protein, whereas P86R alters both VHL proteins. Based on the positions of the mutations, P86R is more likely to be pathogenically significant than the P25L mutation. A survey of anonymized DNAs for P25L, using allele-specific PCR, revealed that it is a variant with an allele frequency of approximately 0.5%. CONCLUSION: P25L is a rare variant of the VHL gene and cannot be considered a cause of VHL disease. However, this work does not prove that P25L is entirely innocuous.

Adolescent↗
PubMed2001

Antihypertensive medication use in Hispanic adults: a comparison with black adults and white adults.

BACKGROUND: Variations in awareness, treatment, and control of hypertension among different racial/ethnic groups have been widely reported. It is unclear whether these differences are explained fully by differences in socioeconomic status, insurance coverage, health status, and health behaviors, or whether these differences indicate that racial/ethnic subgroups have unique barriers to hypertension control. OBJECTIVES: Determine whether there are significant differences between racial/ethnic groups in medication use for hypertension after adjusting for potentially confounding variables. RESEARCH DESIGN: Cross-sectional analysis of the 1992 Health and Retirement Study. SUBJECTS: 2450 non-Hispanic white, 939 non-Hispanic black, and 345 Hispanic participants, ages 51 to 61, reporting a history of hypertension. MEASURES: Self-reported current antihypertensive medication use. We used logistic regression to adjust for demographics, socioeconomic status, health status, insurance, and health risk behaviors. RESULTS: 63.6% of white adults, 72.6% of black adults, and 52.5% of Hispanic adults reported current medication use to control hypertension (P <0.001 across all three groups). In stratified analysis, the lower rate of use for Hispanic adults was consistent regardless of gender, insurance coverage, or health status. After controlling for all variables, the adjusted prevalence for Hispanic adults was 50.8% and 73.3% for black adults. CONCLUSIONS: The differences in antihypertensive medication use between white adults, black adults, and Hispanic adults, particularly the markedly lower rates among Hispanic adults, are not explained by differences in demographics, socioeconomic status, health insurance coverage, health status, or health risk behaviors. Alternative explanations for these results and areas for future research and intervention are explored.

Black or African American↗
PubMed2000

Health insurance and access to care for symptomatic conditions.

BACKGROUND: The uninsured receive less medical care than the insured. However, it is not known whether the uninsured are less likely to seek medical care for highly "serious" or "morbid" symptoms. METHODS: Participants in the National Access to Care Survey were asked whether they had experienced any of 15 highly serious or morbid symptoms. Those who did were asked whether they received medical care and, if care was not received, whether care was thought to have been necessary. RESULTS: A total of 574 respondents (16.4%) reported 794 new serious or morbid symptoms. Of these, 499 people (86.9%) had health insurance, and they reported 691 new symptoms; 75 (13.1%) lacked health insurance, and they reported 103 symptoms. The uninsured were less likely to have received medical care and more likely to say they did not receive care even though they thought it was needed (P = .001). Medical care was received for 45.4% of symptoms for the insured and 24.3% for the uninsured; care was not thought to have been needed for 41.0% of symptoms for the insured and 45.6% for the uninsured; and care was thought necessary but was not received for 13.6% of symptoms for the insured and 30.1% for the uninsured. In multivariate analysis, the uninsured were much less likely to have received care than the insured (adjusted odds ratio, 0.43; 95% confidence interval, 0.23-0.81). CONCLUSION: Lack of health insurance is a major barrier to receiving medical care, even for highly serious and morbid symptoms.

Adolescent↗
PubMed2000

Racial differences in the utilization of oral anticoagulant therapy in heart failure: a study of elderly hospitalized patients.

To assess racial differences in the use of oral anticoagulant therapy for patients with heart failure, we conducted a cohort study of 30 hospitals in northeast Ohio. For 12,911 Medicare enrollees consecutively admitted in 1992 through 1994 with heart failure, crude and adjusted odds of being on oral anticoagulation were determined. The crude and adjusted odds of being African Americans on oral anticoagulant therapy relative to whites were 0.57 (95% confidence interval 0.47-0.69) and 0.55 (95% confidence interval 0. 45-0.67), respectively. African-Americans with heart failure were much less likely than whites to receive oral anticoagulant therapy, even after adjusting for other variables associated with anticoagulant use.

Administration, Oral↗
PubMed2000

Safely directing patients to appropriate levels of care: guideline-driven triage in the emergency service.

STUDY OBJECTIVE: We sought to develop and validate standardized clinical criteria to identify patients presenting to the emergency department whose care may be safely deferred to a later date in a nonemergency setting. METHODS: Using a modified Delphi process, a 17-member multidisciplinary physician panel developed explicit, standardized, deferred-care criteria. In a prospective cohort design, emergency nurses at a tertiary care Veterans Administration (VA) Medical Center, using the criteria, screened 1,187 consecutive ambulatory adult patients presenting with abdominal pain, musculoskeletal symptoms, or respiratory infection symptoms. Patients meeting deferred-care criteria were offered the option of an appointment within 1 week in the ambulatory care clinic at the study site; all other patients were offered same-day care. As outcome measures, we assessed nonelective hospitalizations for related conditions occurring within 7 days of evaluation at our facility or any other VA facility within a 300-mile radius, and we assessed 30-day all-cause mortality. RESULTS: Two hundred twenty-six (19%) patients met screening criteria for deferred care. Patients meeting deferred-care criteria experienced zero (95% confidence interval, 0% to 1.2%) related nonelective VA hospitalizations within 7 days of evaluation, and none died within 30 days. By contrast, 68 (7%) of 961 (95% confidence interval, 5.5% to 8.9%) patients who did not meet deferred-care criteria were hospitalized nonelectively for related conditions, and 5 (0.5%) died. CONCLUSION: By using hospitalization and 30-day mortality as safety gauges, standardized clinical criteria can identify, at presentation, VA ED users who may be safely cared for at a later date in a nonemergency setting. These guidelines apply to a significant proportion of VA ED users with common ambulatory conditions. These criteria deserve testing in other ED settings.

Adult↗
PubMed2000

The association between age and health literacy among elderly persons.

OBJECTIVE: To examine why older age groups have worse functional health literacy. METHODS: Home interviews were conducted with community-dwelling elderly persons (n = 2,774) to determine demographics, years of school completed, newspaper reading frequency, chronic diseases, and health status. Participants completed the Short Test of Functional Health Literacy in Adults (S-TOFHLA, range 0-100) and the Mini Mental State Examination (MMSE). RESULTS: Mean S-TOFHLA scores declined 1.4 points (95% CI 1.3-1.5) for every year increase in age (p < .001). After adjusting for sex, race, ethnicity, and education, the S-TOFHLA score declined 1.3 points (95% CI 1.2-1.4) for every year increase in age. Even after adjustment for performance on the MMSE, the S-TOFHLA score declined 0.9 points (95% CI 0.8-1.0) for every year increase in age (p < .001). Differences in newspaper reading frequency, visual acuity, chronic medical conditions, and health status, did not explain the lower literacy of older participants. DISCUSSION: Functional health literacy was markedly lower among older age groups even after adjusting for differences in MMSE performance, newspaper reading frequency, health status, and visual acuity. Future studies should prospectively examine whether functional literacy declines with age and whether this is explained by declines in cognitive function.

Activities of Daily Living↗
PubMed2000

Effect of language barriers on follow-up appointments after an emergency department visit.

OBJECTIVE: To determine whether patients who encountered language barriers during an emergency department visit were less likely to be referred for a follow-up appointment and less likely to complete a recommended appointment. DESIGN: Cohort study. SETTING: Public hospital emergency department. PARTICIPANTS: English- and Spanish-speaking patients (N = 714) presenting with nonemergent medical problems. MEASUREMENTS AND MAIN RESULTS: Patients were interviewed to determine sociodemographic information, health status, whether an interpreter was used, and whether an interpreter should have been used. The dependent variables were referral for a follow-up appointment after the emergency department visit and appointment compliance, as determined by chart review and the hospital information system. The proportion of patients who received a follow-up appointment was 83% for those without language barriers, 75% for those who communicated through an interpreter, and 76% for those who said an interpreter should have been used but was not (P =. 05). In multivariate analysis, the adjusted odds ratio for not receiving a follow-up appointment was 1.92 (95% confidence interval [CI], 1.11 to 3.33) for patients who had an interpreter and 1.79 (95% CI, 1.00 to 3.23) for patients who said an interpreter should have been used (compared with patients without language barriers). Appointment compliance rates were similar for patients who communicated through an interpreter, those who said an interpreter should have been used but was not, and those without language barriers (60%, 54%, and 64%, respectively; P =.78). CONCLUSIONS: Language barriers may decrease the likelihood that a patient is given a follow-up appointment after an emergency department visit. However, patients who experienced language barriers were equally likely to comply with follow-up appointments.

Adolescent↗
PubMed2000

Limited English proficiency and Latinos' use of physician services.

Many Latinos have limited English proficiency and this may negatively affect their use of health care services. To examine this, the authors interviewed 465 Spanish-speaking Latinos and 259 English speakers of various ethnicities who presented to a public hospital emergency department with non-urgent medical problems to assess previous physician visits, sociodemographic characteristics, and level of English proficiency. The proportion of patients who reported no physician visit during the 3 months before study enrollment was not related to English proficiency. However, among the 414 patients who saw a physician at least once, Latinos with fair and poor English proficiency reported approximately 22 percent fewer physician visits (p = 0.020 and p = 0.015, respectively) than non-Latinos whose native language was English, even after adjusting for other determinants of physician visits. The magnitude of the association between limited English proficiency and number of physician visits was similar to that for having poor health, no health insurance, or no regular source of care.

Adult↗