Biomedical subjects

S L Bernard

Publications and source records attributed to S L Bernard.

At least 19 recordsLinked to original sources

PubMed2001

Spatial distribution of nutritive and nonnutritive vascular routes in perfused rat hindlimb muscle using microspheres.

Skeletal muscle appears to have two vascular flow routes, nutritive and nonnutritive, where the balance of flow is controlled by vasoconstrictors. In the present study, spatial distributions of the two flow routes in muscles of the perfused rat hindlimb were attempted using fluorescent microspheres (15 microm in diameter). Microspheres were injected during steady-state perfusion with norepinephrine (proposed recruiter of nutritive flow), serotonin (proposed recruiter of nonnutritive flow), or vehicle. The three-dimensional location of individual microspheres in representative muscles was determined using a Fluorescent Imaging CryoMicrotome. Norepinephrine and serotonin each increased perfusion pressure (P < 0.05) but stimulated and inhibited oxygen consumption (P < 0.05), respectively. The distribution of microspheres lodged in muscle was independent of the agent used. Spatial perfusion indices for norepinephrine, serotonin, and vehicle did not differ from each other. Similarly, there was no difference in these indices for a theoretical distribution where microspheres were deliberately positioned in muscle bundle capillaries or interfibrillar connective tissue vessels. We conclude that the nutritive and nonnutritive flow routes are distributed throughout muscle sections consistent with their locations in muscle bundle capillaries and interfibrillar connective tissue, respectively.

Animals↗

PubMed2001

Medicare beneficiary satisfaction with durable medical equipment suppliers.

CMS has recently launched a series of initiatives to control Medicare spending on durable medical equipment (DME) and prosthetics, orthotics, and supplies (DMEPOS). An important question is how these initiatives will affect beneficiary satisfaction. Using survey data, we analyze Medicare beneficiary satisfaction with DMEPOS suppliers in two Florida counties. Our results show that beneficiaries are currently highly satisfied with their DMEPOS suppliers. Beneficiary satisfaction is positively related to rapid delivery, training, dependability, and frequency of service. Results of our analysis can be used as baseline estimates in evaluating CMS initiatives to reduce Medicare payments for DMEPOS.

Aged↗

PubMed2000

Self-reported arthritis-related disruptions in sleep and daily life and the use of medical, complementary, and self-care strategies for arthritis: the National Survey of Self-care and Aging.

OBJECTIVE: To assess relations between self-reported arthritis-related disruptions in sleep, physical activity, and social functioning and use of medical care, complementary therapies, and self-care for arthritis in older adults. DESIGN: A survey of self-reported arthritis-related disruptions in sleep and daily life as risk factors for use of 15 medical, complementary, and self-care modalities for relief of arthritis symptoms. SETTING: General community from 38 urban and 12 rural areas in the contiguous United States. PARTICIPANTS: Nine hundred thirty-seven older persons reporting arthritis; of the 1925 in the 1993 to 1994 follow-up of the National Survey of Self-care and Aging, a population-based, stratified, random sample of noninstitutionalized Medicare beneficiaries aged 65 years and older. MAIN OUTCOME MEASURES: Use of 15 medical, self-care, and complementary modalities for relief of arthritis symptoms. RESULTS: Most respondents reported use of at least 1 medical, complementary, or self-care strategy for arthritis. Arthritis was reported to disrupt sleep and leisure in 32.8% and 33.4% of respondents, respectively. Individuals with sleep disruption were more likely than those without sleep disturbance to use medical, complementary, and self-care strategies (adjusted odds ratio [95% confidence interval], 2.31 [1.59-3.37] for seeing a physician; and 2.23 [1.60-3.10] for using physical modalities). Reported disruption in sleep from arthritis was associated with use of more medical, complementary, and self-care strategies than was any other disruption. CONCLUSIONS: Self-reported arthritis-related disruption in sleep is associated with use of a wide range of medical, complementary, and self-care strategies. Physicians, other health care providers, and researchers should not overlook the importance of this common and often-neglected symptom.

Activities of Daily Living↗

PubMed2000

Self-care practices used by older men and women to manage urinary incontinence: results from the national follow-up survey on self-care and aging.

OBJECTIVES: To estimate the extent to which self-care practices are employed by older adults with urinary incontinence (UI); to determine how demographic and functional status measures are associated with self-care practice use; and to explore the relationship between contacting a doctor and disposable pad use. DESIGN: A cross-sectional analysis of a national probability sample using multiple logistic regression. SETTING: Responses of subjects with UI (n = 787) from the 1993-1994 National Follow-up Survey on Self-Care and Aging, a follow-up survey of older Medicare beneficiaries living in the community within the contiguous United States drawn in 1990-1991 MEASURES: Subject responses about UI, fecal incontinence, dressing, eating, bathing, Instrumental Activities of Daily Living (IADL), Mobility Activities of Daily Living (MADL), age, gender, place of residence, race, education, proxy response to the survey, and self-reported medical conditions. RESULTS: Self-care practices used by more than 25% of respondents with UI included using disposable pads, limiting trips, and limiting fluids. Among older adults with incontinence, more women used disposable pads (44.5%; 95% CI, 36.9-52.1) and performed exercises (14.2%; 95% CI, 9.7-18.9) than did men (15.1%; 95% CI, 8.1-22.1; and 4.3%; 95% CI, 1.0-7.7, respectively). Bi-variate analysis showed respondents with severe UI or fecal incontinence reported greater use of self-care practices. In multivariate models of the three most commonly used self-care practices, measures of UI severity were not always associated independently with self-care practice use, whereas ADL measures of functional status were. Disposable pad use was positively independently associated (OR 3.36; 95% CI, 2.01-5.63) in multivariate models with contacting a doctor about incontinence, even after controlling for age, gender, demographics, and self-reported medical conditions. CONCLUSIONS: Use by older adults of self-care practices to manage urinary incontinence is predicted independently in multivariate models by measures of functional status such as dressing, eating, bathing, IADLs or MADLs, but not by all UI measures. Disposable pad users had increased odds of contacting a doctor, suggesting that self-care practices and formal medical care are not always inversely related.

Activities of Daily Living↗

PubMed2000

Maternal complications of normal deliveries: variation among rural hospitals.

This study examined variation in maternal complication rates following normal vaginal delivery among 282 rural hospitals throughout the United States. Using a risk-adjusted model to control for case mix, discharge abstracts of more than 84,000 women were analyzed to determine whether there were differences in outcomes resulting from, or concomitant with, their hospital stay. After risk adjustment, the majority of hospitals were found to be performing at an acceptable level; however, there were some factors associated with poor performance. Hospital volume and the availability of obstetricians in the county in which the hospital was located were found to have an inverse association with complication rates, whereas low county per capita income was found to have a positive association with poor facility performance. No association was found between complication rates and general practitioners and the degree of remoteness as defined by distance from the nearest tertiary care facility. The results demonstrate a relationship between volume and outcome and a threshold point at which volume becomes a significant factor in predicting facility performance. As well, a relationship is seen between physician specialty and outcome, in which obstetricians are significantly associated with facility performance at expected or better-than-expected levels. Normal vaginal delivery is an important service provided by rural hospitals. The relationships among volume, physician specialty and outcome suggested by these findings require further in-depth examination of specific factors that affect patient outcomes and overall facility performance.

Adolescent↗

PubMed2000

High spatial resolution measurements of organ blood flow in small laboratory animals.

With the use of a newly developed Imaging Cryomicrotome to determine the spatial location of fluorescent microspheres in organs, we validate and report our processing algorithms for measuring regional blood flow in small laboratory animals. Microspheres (15-microm diameter) of four different fluorescent colors and one radioactive label were simultaneously injected into the left ventricle of a pig. The heart and kidneys were dissected, and the numbers of fluorescent and radioactive microspheres were determined in 10 randomly selected pieces. All microsphere counts fell well within the 95% expected confidence limits as determined from the radioactive counts. Fluorescent microspheres (15-microm diameter) of four different colors were also injected into the tail vein of a rat and the left ventricle of a rabbit. After correction for Poisson noise, correlation coefficients between the colors were 0.99 +/- 0.02 (means +/- SD) for the rabbit heart and 0.99 +/- 0.02 for the rat lung. Mathematical dissection algorithms, statistics to analyze the spatial data, and methods to visualize blood flow distributions in small animal organs are presented.

Animals↗

PubMed2000

Exercise alters fractal dimension and spatial correlation of pulmonary blood flow in the horse.

We determined the changes in fractal dimensions and spatial correlations of regional pulmonary blood flow with increasing exercise in race horses (n = 4) by using 15-microm fluorescent microspheres. Fluorescence was measured to quantitate regional blood to 1.3-cm(3) samples (n = 1,621-2,503). Perfusion distributions were characterized with fractal dimensions (a measure of spatial variability) and spatial correlations. On average, the fractal dimension decreased with exercise (trot 1.216 to gallop 1.173; P < 0. 05) despite a variable fractal dimension at rest. Spatial correlation of flow to neighboring pieces increased with exercise (trot 0.57 +/- 0.074 to gallop 0.73 +/- 0.051) and was inversely correlated with fractal dimension, indicating better spatial correlation as blood flow distribution becomes more uniform. This is the first study to document a change in fractal dimension as a result of increasing pulmonary blood flow. Spatial differences in response to vasoregulatory mediators may play a role in this phenomenon.

Algorithms↗

PubMed2000

Effects of inertial load and countermeasures on the distribution of pulmonary blood flow.

We assessed the influence of cranial-to-caudal inertial force (+G(z)) and the countermeasures of anti-G suit and positive pressure breathing during G (PBG), specifically during +G(z), on regional pulmonary blood flow distribution. Unanesthetized swine were exposed randomly to 0 G(z) (resting), +3 G(z), +6 G(z), and +9 G(z), with and without anti-G suit and PBG with the use of the Air Force Research Laboratory centrifuge at Brooks Air Force Base (the gravitational force of the Earth, that is, the dorsal-to-ventral inertial force, was present for all runs). Fluorescent microspheres were injected into the pulmonary vasculature as a marker of regional pulmonary blood flow. Lungs were excised, dried, and diced into approximately 2-cm(3) pieces, and the fluorescence of each piece was measured. As +G(z) was increased from 0 to +3 G(z), blood flow shifted from cranial and hilar regions toward caudal and peripheral regions of the lung. This redistribution shifted back toward cranial and hilar regions as anti-G suit inflation pressure increased at +6 and +9 G(z). Perfusion heterogeneity increased with +G(z) stress and decreased at the higher anti-G suit pressures. The distribution of pulmonary blood flow was not affected by PBG. ANOVA indicated anatomic structure as the major determinant of pulmonary blood flow.

Animals↗

PubMed2000

Hemodynamic effects of 15-microm-diameter microspheres on the rat pulmonary circulation.

The microsphere method has been used extensively to measure regional blood flow in large laboratory animals. A fundamental premise of the method is that microspheres do not alter regional flow or vascular tone. Whereas this assumption is accepted in large animals, it may not be valid in the pulmonary circulation of smaller animals. Three studies were performed to determine the hemodynamic effects of microspheres on the rat pulmonary circulation. Increasing numbers of 15-microm-diameter microspheres were injected into a fully dilated, isolated-lung preparation. Vascular resistance increased 0.8% for every 100,000 microspheres injected. Microspheres were also injected into an isolated-lung preparation in which vascular tone was increased with hypoxia. Microspheres did not induce vasodilatation, as reported in other vascular beds. Fluorescent microspheres were injected via tail veins into awake rats, and the spatial locations of the microspheres were determined. Regional distributions remained highly correlated when microspheres of one color were injected after microspheres of another color. This indicates that the initial injection did not alter regional perfusion. We conclude that, when used in appropriate numbers, 15-microm-diameter microspheres do not alter regional flow or vascular tone in the rat pulmonary circulation.

Adenosine↗

PubMed2000

Pulmonary blood flow remains fractal down to the level of gas exchange.

The spatial distribution of pulmonary blood flow is increasingly heterogeneous as progressively smaller lung regions are examined. To determine the extent of perfusion heterogeneity at the level of gas exchange, we studied blood flow distributions in rat lungs by using an imaging cryomicrotome. Approximately 150,000 fluorescent 15-microm-diameter microspheres were injected into tail veins of five awake rats. The rats were heavily anesthetized; the lungs were removed, filled with an optimal cutting tissue compound, and frozen; and the spatial location of every microsphere was determined. The data were mathematically dissected with the use of an unbiased random sampling method. The coefficients of variation of microsphere distributions were determined at varying sampling volumes. Perfusion heterogeneity increased linearly on a log-log plot of coefficient of variation vs. volume, down to the smallest sampling size of 0.53 mm(3). The average fractal dimension, a scale-independent measure of perfusion distribution, was 1.2. This value is similar to that of other larger species such as dogs, pigs, and horses. Pulmonary perfusion heterogeneity increases continuously and remains fractal down to the acinar level. Despite the large degree of perfusion heterogeneity at the acinar level, gases are efficiently exchanged.

Algorithms↗

PubMed2000

Selected contribution: redistribution of pulmonary perfusion during weightlessness and increased gravity.

To compare the relative contributions of gravity and vascular structure to the distribution of pulmonary blood flow, we flew with pigs on the National Aeronautics and Space Administration KC-135 aircraft. A series of parabolas created alternating weightlessness and 1.8-G conditions. Fluorescent microspheres of varying colors were injected into the pulmonary circulation to mark regional blood flow during different postural and gravitational conditions. The lungs were subsequently removed, air dried, and sectioned into approximately 2 cm(3) pieces. Flow to each piece was determined for the different conditions. Perfusion heterogeneity did not change significantly during weightlessness compared with normal and increased gravitational forces. Regional blood flow to each lung piece changed little despite alterations in posture and gravitational forces. With the use of multiple stepwise linear regression, the contributions of gravity and vascular structure to regional perfusion were separated. We conclude that both gravity and the geometry of the pulmonary vascular tree influence regional pulmonary blood flow. However, the structure of the vascular tree is the primary determinant of regional perfusion in these animals.

Animals↗

PubMed2000

Urinary incontinence and risk of death among community-living elderly people: results from the National Survey on Self-Care and Aging.

OBJECTIVES: The authors explored whether urinary incontinence (UI) is associated with higher mortality and, if so, whether adjustment for demographics, health, and functional status diminishes the association. METHODS: The Cox proportional hazards model was used with a nationally representative sample of community-living elderly people (N = 3,485). RESULTS: In an analysis adjusted for age, gender, education, and probability sampling design, participants with mild to moderate UI (hazard ratio [HR] = 1.51; 95% confidence interval [CI] = 1.09-2.08) and severe UI (HR = 1.54; 95% CI = 1.03-2.29) experienced a higher risk of death. Adjustment for health and functional status diminished the association of UI and risk of death (mild to moderate UI, HR = 1.20, 95% CI = 0.85-1.68; severe UI, HR = 0.91, 95% CI = 0.59-1.39). DISCUSSION: The relationship between UI and mortality in older adults can largely be understood on the basis of increased frailty in incontinent individuals.

Activities of Daily Living↗

PubMed2000

The economic implications of self-care: the effect of lifestyle, functional adaptations, and medical self-care among a national sample of Medicare beneficiaries.

OBJECTIVES: Self-care includes actions taken by individuals to promote or ensure their health, to recover from diseases or injuries, or to manage their effects. This study measured associations between self-care practices (lifestyle practices, adaptations to functional limitations, and medical self-care) and Medicare expenditures among a national sample of adults 65 years and older. METHODS: Regression models of Medicare use and expenditures were estimated by using the National Survey of Self-Care and Aging and Medicare claims for 4 years following a baseline interview. RESULTS: Lifestyle factors (swimming and walking) and functional adaptations (general home modifications) were associated with reductions in monthly Medicare expenditures over a 12-month follow-up period. Expenditure reductions were found over the 48-month follow-up period for participation in active sports, gardening, and medical self-care. Practices associated with increases in expenditures included smoking, physical exercise (possibly of a more strenuous nature), and specific home modifications. CONCLUSIONS: Certain self-care practices appear to have significant implications for Medicare expenditures and presumptively for the health status of older adults. Such practices should be encouraged among older adults as a matter of national health policy.

Activities of Daily Living↗

PubMed2000

Reconstruction of the burned nose and ear.

Patients who have survived thermal injuries to the face suffer from severe disfigurement. When the nose and ear are involved, the resulting deformities are immediately obvious to all who see the patient. This level of injury results in a self-imposed confinement; the patients never leave their homes. It is therefore important that we plastic surgeons know, understand, and use all options available to improve our patients' appearance and ultimately their mental and physical well being.

Burns↗

PubMed1999

Effect of furosemide on pulmonary blood flow distribution in resting and exercising horses.

We determined the spatial distribution of pulmonary blood flow (PBF) with 15-micron fluorescent-labeled microspheres during rest and exercise in five Thoroughbred horses before and 4 h after furosemide administration (0.5 mg/kg iv). The primary finding of this study was that PBF redistribution occurred from rest to exercise, both with and without furosemide. However, there was less blood flow to the dorsal portion of the lung during exercise postfurosemide compared with prefurosemide. Furosemide did alter the resting perfusion distribution by increasing the flow to the ventral regions of the lung; however, that increase in flow was abated with exercise. Other findings included 1) unchanged gas exchange and cardiac output during rest and exercise after vs. before furosemide, 2) a decrease in pulmonary arterial pressure after furosemide, 3) an increase in the slope of the relationship of PBF vs. vertical height up the lung during exercise, both with and without furosemide, and 4) a decrease in blood flow to the dorsal region of the lung at rest after furosemide. Pulmonary perfusion variability within the lung may be a function of the anatomy of the pulmonary vessels that results in a predominantly fixed spatial pattern of flow distribution.

Animals↗

PubMed1998

The association of urinary incontinence with poor self-rated health.

OBJECTIVES: To assess whether urinary incontinence (UI) and its severity are associated with poor self-rated health in a national sample of community-living older adults and whether this relationship persists after controlling for confounding attributable to functional status, comorbidity, and demographic factors. DESIGN: A cross-sectional analysis using multivariate logistic regression. SETTING: Subjects were from the 1990-1991 National Survey of Self-Care and Aging (N = 3485), a random sampling in geographic clusters of community-dwelling Medicare beneficiaries 65 years of age or older in the contiguous United States. MEASURES: The responses to an interviewer-administered questionnaire regarding urinary incontinence, Basic Activities of Daily Living (BADL), Instrumental Activities of Daily Living (IADL), Mobility Activities of Daily Living (MADL), age, gender, place of residence, race, education, need for proxy response to the survey, and number of medical conditions. RESULTS: Unadjusted analysis showed the presence of urinary incontinence to be associated with poor self-rated health (OR 2.7, 2.1-3.3). With gender, number of comorbid conditions, race, IADL impairment, and interaction terms of incontinence/race and incontinence/IADL in the final model, UI was associated with poor self-rated health in certain subgroups. White subjects with no IADL impairment and mild-moderate incontinence had an OR of 2.0 (95% CI 1.5-2.9) and those with severe incontinence had an OR of 4.5 (95% CI 2.4-8.4) of rating their health as poor, whereas those with no IADL impairment and no incontinence were the referent group. For those with a lot of difficulty performing one or more IADL activity, the association of UI and poor self-rated health was weak. For non-white subjects, there was no association, or a very weak association, of UI and poor self-rated health. CONCLUSION: In this national sample, urinary incontinence was independently and positively associated with poor self-rated health after adjustment for age, comorbidity, and frailty for most community-dwelling older adults. This association between UI and poor self-rated health was weaker and statistically insignificant when IADL impairment was present or in non-white subjects. Further research is indicated to better understand the impact of urinary incontinence in specific cultural settings.

Activities of Daily Living↗

PubMed1998

Histological methods to determine blood flow distribution with fluorescent microspheres.

We evaluated several histological methods and determined their advantages and disadvantages for histological studies of tissues and organs perfused with fluorescent microspheres. Microspheres retained their fluorescence in 7-10 microm serial sections with a change in the antimedium from toluene when samples were fixed in formalin and embedded in paraffin. Several antimedia allowed both wax infiltration of tissue and preservation of microsphere fluorescence. Histoclear II was the best substitute for toluene. When samples were fixed in formalin and embedded in glycol methacrylate, thinner (3-5 microm) sections provided greater histological detail but had fewer microspheres per section. Air dried lung tissue followed by Vibratome sectioning provided thick sections (100 microm) that facilitated rapid survey of large volumes of tissue for microspheres but limited histological detail, and the air drying procedure was restricted to lung tissue. Samples fixed in formalin followed by Vibratome sectioning of unembedded tissue provided better histological detail of lung tissue and was also useful for other organs. These sections were more difficult to handle and to mount on slides compared to air dried tissue, whereas fixed tissue embedded in gelatin provided better tissue support for Vibratome sectioning. Rapid freezing followed by cryo-microtome sectioning resulted in frozen sections that were relatively difficult to handle compared to embedded or unembedded tissue; they also deteriorated relatively rapidly with time. Paraffin sections were stained with hematoxylin and eosin or with aqueous methyl green, although tissue autofluorescence by itself was usually sufficient to identify histological features. Methacrylate sections quenched tissue autofluorescence, and Lee's stain or Richardson's stain were used for staining sections. Toluene based mountants such as Cytoseal quenched fluorescence, particularly the red fluorescent microspheres. Aqueous based mountants such as Aquamount, Crystal/Mount, Fluoromount-G were substituted, although such preparations were not as permanent as Cytoseal mounted coverglasses and tended to cause fading of stained sections.

Animals↗

PubMed1997

Predicting mortality from community surveys of older adults: the importance of self-rated functional ability.

Using data from the 1990 baseline of the National Survey of Self-Care and Aging (NSSCA), and nearly three years of follow-up mortality data, we examined the association between self-rated functional ability, a global measure of perceived ability of function independently, and mortality among a national sample of older adults. The study included 3,485 subjects selected from the Medicare Beneficiary Files according to a stratified random sampling design, with approximately equal numbers of adults by gender in each of three age categories, 65-74, 75-84, and 85 and over. Self-rated functional ability was found to have an independent contribution to the subsequent risk of death among older adults. Using multivariate models that accounted for self-rated health, age, gender, medical conditions, functional status, and assistance from others, poor self-ratings on this single item nearly doubled the risk of death during the follow-up period. These findings suggest the importance, for both researchers and clinicians, of measuring the potential prognostic importance of self-ratings of health and self-ratings of functional ability among older adults.

Activities of Daily Living↗