Biomedical subjects

Danielle Harvey

Publications and source records attributed to Danielle Harvey.

14 recordsLinked to original sources

PubMed2007

Qualitative estimates of medial temporal atrophy as a predictor of progression from mild cognitive impairment to dementia.

BACKGROUND: Individuals diagnosed as having mild cognitive impairment (MCI) have a high likelihood of progressing to dementia within 3 to 5 years, but not all individuals with MCI progress to dementia. Prognostic uncertainty suggests the need for additional measures to assist the clinician. OBJECTIVE: To assess the added value of qualitative measures of medial temporal atrophy (MTA) to estimate the relative risk of progressing from MCI to dementia. DESIGN: A 3-year, double-blind, placebo-controlled Alzheimer's Disease Cooperative Study initially designed to evaluate the efficacy of donepezil hydrochloride or vitamin E vs placebo to delay progression of MCI to dementia. SETTING: Memory assessment centers. PATIENTS: A total of 190 individuals with MCI. MAIN OUTCOME MEASURES: Ratings of MTA performed using magnetic resonance images obtained at baseline. Log-rank tests and Cox proportional hazards ratios examining the significance of MTA estimates in predicting progression of MCI to dementia. RESULTS: A mean MTA score greater than 2.0 was associated with a greater than 2-fold increased likelihood of progression to dementia during the observation period (hazards ratio, 2.30; 95% confidence interval, 1.09-4.92; P = .03) after controlling for age, education, sex, and baseline Mini-Mental State Examination score. CONCLUSIONS: Adjusted estimates of MTA were associated with significantly increased risk of developing dementia within 3 years, suggesting that obtaining a magnetic resonance image during the evaluation of MCI may offer additional independent information about the risk of progression to dementia. Given the relatively high prevalence of MCI in the general population, use of this method as part of routine clinical evaluation may help identify individuals who might benefit from increased surveillance and future treatment. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00000173.

Aged↗

PubMed2006

Venous thromboembolism in patients with colorectal cancer: incidence and effect on survival.

PURPOSE: To describe the incidence and outcomes associated with venous thromboembolism (VTE) among patients with colorectal cancer. METHODS: This was a retrospective analysis of all colorectal cancer patients diagnosed in California between 1993 and 1995 and 1997 to 1999. Principal outcomes were incident symptomatic VTE events and death. Associations between specific risk factors and principal outcomes were analyzed using Cox proportional hazards models. RESULTS: Among 68,142 colorectal cancer patients, 50% were women, mean age was 70 +/- 15 years, and approximately 70% underwent a major operation. The 2-year cumulative incidence of VTE was 2,100 patients (3.1%), with an incidence rate that decreased significantly over time from 5.0% (events/100 patient-years) in months 0 to 6 to 1.4% during months 7 to 12 to 0.6% during the second year. Significant predictors of VTE included metastatic stage (hazard ratio [HR] = 3.2; 95% CI, 2.8 to 3.8) and three or more comorbid conditions (HR = 2.0; 95% CI, 1.7 to 2.3). The risk of VTE was significantly reduced among Asians/Pacific Islanders (HR = 0.4; 95% CI, 0.3 to 0.5.) and patients who underwent an abdominal operation (HR = 0.4; 95% CI, 0.3 to 0.4). In risk-adjusted models, VTE was a significant predictor of death within 1 year of cancer diagnosis among patients with local- (HR = 1.8; 95% CI, 1.4 to 2.3) or regional-stage disease (HR = 1.5; 95% CI, 1.3 to 1.8) but not among patients with metastatic disease (HR = 1.1; 95% CI, 1.0 to 1.2). CONCLUSION: The incidence of VTE among colorectal cancer patients was highest in the first 6 months after diagnosis and decreased rapidly thereafter. Metastatic disease and the number of medical comorbidities were the strongest predictors of VTE. Incident VTE reduced survival among patients with local or regional disease, suggesting that, in these patients, VTE may reflect the presence of a biologically more aggressive cancer.

Aged↗

PubMed2006

Incidence of venous thromboembolism and its effect on survival among patients with common cancers.

BACKGROUND: The incidence of venous thromboembolism after diagnosis of specific cancers and the effect of thromboembolism on survival are not well defined. METHODS: The California Cancer Registry was linked to the California Patient Discharge Data Set to determine the incidence of venous thromboembolism among cancer cases diagnosed between 1993 and 1995. The incidence and timing of thromboembolism within 1 and 2 years of cancer diagnosis and the risk factors associated with thromboembolism and death were determined. RESULTS: Among 235 149 cancer cases, 3775 (1.6%) were diagnosed with venous thromboembolism within 2 years, 463 (12%) at the time cancer was diagnosed and 3312 (88%) subsequently. In risk-adjusted models, metastatic disease at the time of diagnosis was the strongest predictor of thromboembolism. Expressed as events per 100 patient-years, the highest incidence of thromboembolism occurred during the first year of follow-up among cases with metastatic-stage pancreatic (20.0), stomach (10.7), bladder (7.9), uterine (6.4), renal (6.0), and lung (5.0) cancer. Adjusting for age, race, and stage, diagnosis of thromboembolism was a significant predictor of decreased survival during the first year for all cancer types (hazard ratios, 1.6-4.2; P<.01). CONCLUSIONS: The incidence of venous thromboembolism varied with cancer type and was highest among patients initially diagnosed with metastatic-stage disease. The incidence rate of thromboembolism decreased over time. Diagnosis of thromboembolism during the first year of follow-up was a significant predictor of death for most cancer types and stages analyzed. For some types of cancer, the incidence of thromboembolism was sufficiently high to warrant prospective clinical trials of primary thromboprophylaxis.

Aged↗

PubMed2006

Longitudinal stability of MRI for mapping brain change using tensor-based morphometry.

Measures of brain change can be computed from sequential MRI scans, providing valuable information on disease progression, e.g., for patient monitoring and drug trials. Tensor-based morphometry (TBM) creates maps of these brain changes, visualizing the 3D profile and rates of tissue growth or atrophy, but its sensitivity depends on the contrast and geometric stability of the images. As part of the Alzheimer's Disease Neuroimaging Initiative (ADNI), 17 normal elderly subjects were scanned twice (at a 2-week interval) with several 3D 1.5 T MRI pulse sequences: high and low flip angle SPGR/FLASH (from which Synthetic T1 images were generated), MP-RAGE, IR-SPGR (N = 10) and MEDIC (N = 7) scans. For each subject and scan type, a 3D deformation map aligned baseline and follow-up scans, computed with a nonlinear, inverse-consistent elastic registration algorithm. Voxelwise statistics, in ICBM stereotaxic space, visualized the profile of mean absolute change and its cross-subject variance; these maps were then compared using permutation testing. Image stability depended on: (1) the pulse sequence; (2) the transmit/receive coil type (birdcage versus phased array); (3) spatial distortion corrections (using MEDIC sequence information); (4) B1-field intensity inhomogeneity correction (using N3). SPGR/FLASH images acquired using a birdcage coil had least overall deviation. N3 correction reduced coil type and pulse sequence differences and improved scan reproducibility, except for Synthetic T1 images (which were intrinsically corrected for B1-inhomogeneity). No strong evidence favored B0 correction. Although SPGR/FLASH images showed least deviation here, pulse sequence selection for the ADNI project was based on multiple additional image analyses, to be reported elsewhere.

Aged↗

PubMed2006

Low-dose warfarin does not decrease the rate of thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy, radiation, and erythropoeitin.

OBJECTIVES: We had previously reported an association between the use of recombinant human erythropoietin (rHuEPO) and thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy and radiation. We hypothesized that low-dose warfarin would be effective prevention for thromboembolic events in this setting. METHODS: A retrospective analysis of patients with cervical or vulvo-vaginal carcinoma receiving chemoradiation and rHuEpo was performed. Thirty-two patients received rHuEpo alone, and 24 received warfarin (1-2 mg) and rHuEpo. The primary endpoint was objectively proven symptomatic venous thrombosis. RESULTS: There was no difference in the baseline characteristics (e.g. age, stage, body mass index, mean and peak hemoglobin, WBC and platelet counts, and number of transfusions) between these two groups. The rate of thrombosis also was not statistically different (P = 0.62). Nine of 24 patients had a symptomatic deep vein thrombosis (DVT) while receiving warfarin compared to 10 of 32 patients not on warfarin. There was no difference between the two groups in the percentage of patients with upper extremity DVT (P = 0.83) or lower extremity DVT (P = 0.64). CONCLUSION: Daily low-dose warfarin did not alter the incidence of symptomatic DVT in patients with cervical or vulvo-vaginal cancer who received rHuEpo in conjunction with chemoradiation.

Anticoagulants↗

PubMed2005

Attenuated poxvirus-based simian immunodeficiency virus (SIV) vaccines given in infancy partially protect infant and juvenile macaques against repeated oral challenge with virulent SIV.

An infant macaque model was developed to test pediatric vaccine candidates aimed at reducing HIV transmission through breast-feeding. Infant macaques were given multiple immunizations during the first 3 weeks of life with recombinant poxvirus vaccines expressing simian immunodeficiency virus (SIV) structural proteins Gag, Pol, and Env (ALVAC-SIV or modified vaccinia virus Ankara [MVA]-SIV). After repeated daily oral inoculations with virulent SIVmac251 at 4 weeks of age, significantly fewer ALVAC-SIV-immunized infants were infected compared with unimmunized infants. Monkeys not infected after oral challenge in infancy were rechallenged at 16 months of age or older by repeated weekly oral SIV exposure; unimmunized animals were infected after fewer SIV exposures than were animals vaccinated with ALVAC-SIV or MVA-SIV. When infected, ALVAC-SIV- and MVA-SIV-vaccinated animals also had reduced viremia compared with unimmunized animals. The results of these investigations suggest that immunization of human infants with poxvirus-based HIV vaccine candidates may offer protection against early and late HIV infection through breastfeeding.

Administration, Oral↗

PubMed2005

Central obesity and the aging brain.

BACKGROUND: Central adiposity as an indicator of visceral fat is linked to vascular and metabolic factors that in turn are related to cognitive decline and dementia. OBJECTIVE: To determine whether larger waist-hip ratio (WHR) is associated with structural brain changes that underlie cognitive decline and dementia. DESIGN: Cross-sectional analysis of an epidemiologic cohort study of cognitive and functional decline (Sacramento Area Latino Study on Aging). SETTING: California Central Valley. PARTICIPANTS: A total of 112 individuals selected from an ongoing cohort study of 1789 older Latino individuals. Baseline anthropomorphic measures (WHR) and measurements of fasting blood glucose, cholesterol, and insulin levels and blood pressure were obtained. MAIN OUTCOME MEASURES: Baseline magnetic resonance images were analyzed quantitatively to determine the hippocampal volumes in the right and left hemispheres and rated for the percentage of white matter hyperintensities. RESULTS: Greater WHR (P = .02) and older age (P<.001) were negatively related to hippocampal volumes. The WHR and age were positively related to white matter hyperintensities (P = .02 and P = .001, respectively). A 1-SD increase in WHR was associated with a 0.2-SD decrease in hippocampal volume and a 27% increase in white matter hyperintensities. These relationships were not affected by adjustment for body mass index, total cholesterol, fasting blood glucose, and insulin levels or systolic blood pressure in the models. CONCLUSION: A larger WHR may be related to neurodegenerative, vascular, or metabolic processes that affect brain structures underlying cognitive decline and dementia.

Aged↗

PubMed2005

Measures of brain morphology and infarction in the framingham heart study: establishing what is normal.

Numerous anatomical and brain imaging studies find substantial differences in brain structure between men and women across the span of human aging. The ability to extend the results of many of these studies to the general population is limited, however, due to the generally small sample size and restrictive health criteria of these studies. Moreover, little attention has been paid to the possible impact of brain infarction on age-related differences in regional brain volumes. Given the current lack of normative data on gender and aging related differences in regional brain morphology, particularly with regard to the impact of brain infarctions, we chose to quantify brain MRIs from more than 2200 male and female participants of the Framingham Heart Study who ranged in age from 34 to 97 years. We believe that MRI analysis of the Framingham Heart Study more closely represents the general population enabling more accurate estimates of regional brain changes that occur as the consequence of normal aging. As predicted, men had significantly larger brain volumes than women, but these differences were generally not significant after correcting for gender related differences in head size. Age explained approximately 50% of total cerebral brain volume differences, but age-related differences were generally small prior to age 50, declining substantially thereafter. Frontal lobe volumes showed the greatest decline with age (approximately 12%), whereas smaller differences were found for the temporal lobes (approximately 9%). Age-related differences in occipital and parietal lobe were modest. Age-related gender differences were generally small, except for the frontal lobe where men had significantly smaller lobar brain volumes throughout the age range studied. The prevalence of MRI infarction was common after age 50, increased linearly with age and was associated with significantly larger white matter hyperintensity (WMH) volumes beyond that associated with age-related differences in these measures. Amongst men, the presence of MRI infarction was associated with significant age-related reductions in total brain volume. Finally, statistically significant associations were found between the volume of MRI infarcts in cubic centimeters and all brain measures with the exception of parietal lobe volume for individuals where the volume of MRI infarctions was measured. These data serve to define age and gender differences in brain morphology for the Framingham Heart Study. To the degree participants of the Framingham Heart Study are representative the general population, these data can serve as norms for comparison with morphological brain changes associated with aging and disease. In this regard, these cross-sectional quantitative estimates suggest that age-related tissue loss differs quantitatively and qualitatively across brain regions with only minor differences between men and women. In addition, MRI evidence of cerebrovascular disease is common to the aging process and associated with smaller regional brain volumes for a given age, particularly for men. We believe quantitative MRI studies of the Framingham community enables exploration of numerous issues ranging from understanding normal neurobiology of brain aging to assessing the impact of various health factors, particularly those related to cerebrovascular disease, that appear important to maintaining brain health for the general population.

Adult↗

PubMed2005

Effect of ethnicity and gender on the incidence of venous thromboembolism in a diverse population in California in 1996.

There have been very few studies that have describe the epidemiology of first-time venous thromboembolism (VTE) in a large, ethnically diverse population. The California Discharge Data Set was used to identify a cohort of cases with incidentVTE in 1996. Cases associated with traditional provoking risk factors were identified and the remaining cases were labeled as idiopathicVTE. Direct standardization using census information was performed to compare incidence rates across races, gender, and gender within race. There were 21,002 cases with incident VTE in 1996, a crude incidence of 90 events per 100,000 adults. Thirty percent of all VTE events were pulmonary embolism. The directly standardized incidence per 100,000 California adults was 93+/-1.7 (+/-95% CI) in women, 85+/-1.7 in men, 103+/-2.1 in Caucasians, 138+/-6.5 in African- Americans, 61+/-2.8 in Hispanics and 29 +/- 2.4 in Asian-Pacific Islanders (p<0.001 for all inter-group comparisons). After adjusting for misclassification of race, the incidence of VTE per 100,000 was 104 in Caucasians, 141 in African-Americans, 55 in Hispanics, and 21 in Asian/Pacific-Islanders. The incidence of idiopathic VTE was significantly lower among both Hispanics and Asian/Pacific-Islanders (p<0.001) than Caucasians or African-Americans. African-Americans were more likely, and Hispanics less likely, to be diagnosed with idiopathic pulmonary embolism compared to Caucasians. The 28 day case-fatality rate among cases with idiopathic VTE was 2%, and it was significantly higher among African-Americans (4.1%) compared to Caucasians (1.8%, p<0.001). There are important differences in the incidence of total and idiopathicVTE and in the proportion of events diagnosed as pulmonary embolism among each of the major racial/ethnic groups in California. Further research is needed to explain these observed differences among the different racial/ethnic groups.

Adolescent↗

PubMed2004

Anatomical mapping of white matter hyperintensities (WMH): exploring the relationships between periventricular WMH, deep WMH, and total WMH burden.

BACKGROUND AND PURPOSE: MRI segmentation and mapping techniques were used to assess evidence in support of categorical distinctions between periventricular white matter hyperintensities (PVWMH) and deep WMH (DWMH). Qualitative MRI studies generally identify 2 categories of WMH on the basis of anatomical localization. Separate pathophysiologies and behavioral consequences are often attributed to these 2 classes of WMH. However, evidence to support these empirical distinctions has not been rigorously sought. METHODS: MRI analysis of 55 subjects included quantification of WMH volume, mapping onto a common anatomical image, and spatial localization of each WMH voxel. WMH locations were then divided into PVWMH and DWMH on the basis of distance from the lateral ventricles and correlations, with total WMH volume determined. Periventricular distance histograms of WMH voxels were also calculated. RESULTS: PVWMH and DWMH were highly correlated with total WMH (R2>0.95) and with each other (R2>0.87). Mapping of all WMH revealed smooth expansion from around central cerebrospinal fluid spaces into more distal cerebral white matter with increasing WMH volume. CONCLUSIONS: PVWMH, DWMH, and total WMH are highly correlated with each other. Moreover, spatial analysis failed to identify distinct subpopulations for PVWMH and DWMH. These results suggest that categorical distinctions between PVWMH and DWMH may be arbitrary, and conclusions regarding individual relationships between causal factors or behavior for PVWMH and DWMH may more accurately reflect total WMH volume relationships.

Aged↗

PubMed2004

Licensed caregiver characteristics and staffing in California acute care hospital units.

PURPOSE: Concerns about declining quality of care and nurse staffing shortages led to legislation mandating minimum nurse-to-patient ratios in the state of California. Although research finds that better registered nurse (RN) staffing results in higher quality of care, little evidence exists on which to base specific nurse-patient ratios. The authors describe the results of a California survey characterizing licensed caregivers, identifying staffing levels by unit type, and describing how staffing levels vary across hospital types. METHODS: A stratified random sample of general acute care hospitals was surveyed to collect cross-sectional data on hospitals' nursing workforce and staffing practices and to assess the impact of potential patient-to-nurse staffing ratios. All academic medical centers; rural, private, and city/county hospitals; and hospitals affiliated with a large group-model health maintenance organization (HMO) were eligible for inclusion. RESULTS: Eighty hospitals were surveyed, representing all major metropolitan areas in the state. Acute care hospitals in California have diverse nursing staffs with variations in education, experience, and employment status. Considerable variations in skill mix were identified, with the proportion of RNs ranging from 30% to 84%, depending on the unit type surveyed. CONCLUSIONS: As states struggle with an anticipated critical shortage of RNs, these results have several implications for health and education policy. Future studies of this type will be needed to evaluate the impact of anticipated changes in the regulation of nurse staffing.

California↗

PubMed2003

Increased incidence of symptomatic venous thrombosis in patients with cervical carcinoma treated with concurrent chemotherapy, radiation, and erythropoietin.

BACKGROUND: Because studies have suggested that anemia has an adverse effect on outcome for patients with cervical carcinoma who are treated with radiation, recombinant human erythropoietin (rHuEpo) has been used increasingly to maintain hemoglobin levels in these patients. Erythropoietin may increase the risk of thrombosis. The authors performed a retrospective analysis to determine whether there was an increased rate of symptomatic venous thrombosis associated with the use of rHuEpo in patients with carcinoma of the uterine cervix and vagina. METHODS: A retrospective, case-control study was performed on consecutive patients with localized carcinoma of the uterine cervix or vagina who were treated with chemotherapy and radiation (chemoradiotherapy). The primary outcome was symptomatic venous thrombosis. RESULTS: One hundred forty-seven patients were reviewed. When they were divided into women who received rHuEpo (n = 75 patients) and women who did not receive rHuEpo (n = 72 patients), there were no significant differences in age, height, weight, disease stage, or body mass index. Fewer patients in the rHuEpo group required transfusions. In the rHuEpo group, 17 of 75 patients had either an upper extremity thrombosis (n = 12 patients) or a lower extremity thrombosis (n = 7 patients): 2 patients had both, and 2 patients had more than 1 event. Two of 72 patients who did not receive rHuEpo had symptomatic thrombosis. Patients who received rHuEpo had an odds ratio (OR) of developing thrombosis of 10.3 (95% confidence interval [95% CI], 2.3-46.2). Multiple logistic regression revealed that only the use of rHuEpo was associated with an increased risk of thrombosis (OR, 15.3; 95% CI, 3.1-76.7). CONCLUSIONS: Patients with cervical carcinoma who received chemoradiotherapy and rHuEpo had an increased risk of symptomatic venous thrombosis.

Adult↗

PubMedDate not supplied

Incidence of venous thromboembolism in the year before the diagnosis of cancer in 528,693 adults.

BACKGROUND: It is unclear how frequently unprovoked venous thromboembolism (VTE) reflects the presence of an occult cancer. METHODS: The California Cancer Registry was used to identify diagnosed cases of 19 common malignancies during a 6-year period. Cases were linked to a hospital discharge database to identify incident VTE events in the year before the cancer diagnosis date. The standardized incidence ratio (SIR) of unprovoked VTE was determined by using the age-, race-, and sex-specific incidence rates in California. RESULTS: Among 528,693 cancer cases, 596 (0.11%) were associated with a diagnosis of unprovoked VTE within 1 year of the cancer diagnosis, compared with 443.0 expected cases (SIR, 1.3; 95% confidence interval, 1.2-1.5; P<.001). Among cases with metastatic-stage cancer, the SIR was 2.3 (95% confidence interval, 2.0-2.6; P<.001), whereas for all other stages, the SIR was 1.07 (95% confidence interval, 0.97-1.18; P = .09). The incidence of preceding VTE was increased over that expected only during the 4-month period immediately preceding the cancer diagnosis date (P<.001). Only 7 cancer types were associated with a significantly elevated SIR: acute myelogenous leukemia; non-Hodgkin lymphoma; and renal cell, ovarian, pancreatic, stomach, and lung cancer (SIR range, 1.8-4.2). CONCLUSIONS: In the year preceding the diagnosis of cancer, the number of cases with unprovoked VTE was modestly higher than expected, and almost all of the unexpected VTE cases were associated with a diagnosis of metastatic-stage cancer within 4 months. Given the timing and advanced stage of the unexpected cases, it is unlikely that earlier diagnosis of these cancers would have significantly improved long-term survival.

Adult↗

PubMedDate not supplied

MCI is associated with deficits in everyday functioning.

The purpose of the present study was to examine the types of impairments in everyday function that accompany mild cognitive impairment (MCI). Data for this study was collected from 434 individuals consecutively evaluated at a university-based Alzheimer's Center. A total of 96 participants were diagnosed with MCI, 105 were cognitively normal, and 233 had dementia. Informant ratings of participants' abilities were obtained across different functional domains reflecting everyday abilities related to memory, language, visual spatial abilities, planning, organization, and divided attention. As expected, the demented group was significantly more impaired than the healthy control and MCI groups across all of the functional domains. The MCI group also showed significantly more functional impairment relative to healthy controls in all of the functional domains. Examination of the effect sizes as a measure of the magnitude of functional impairment in the MCI groups relative to controls showed that the greatest degree of impairment occurred within the Everyday Memory domain. The current findings suggest that individuals with MCI demonstrate deficits in a wide range of everyday functions but that the magnitude of these changes is greatest for those functional abilities that rely heavily on memory.

Activities of Daily Living↗