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Biomedical subjects

D G Fisher

Publications and source records attributed to D G Fisher.

At least 37 records · Page 2Linked to original sources
PubMed1998

Alcohol consumption among Alaskan drug users.

This study investigated predictors of alcohol consumption among drug users not currently in treatment in Anchorage, Alaska. Data were collected from 114 female and 269 male drug users via structured interviews. Alcohol consumption was defined as estimated number of drinks consumed in the last 30 days. Results revealed a high proportion consuming alcohol within the last 48 hours and 30 days (73% and 96%, respectively). Stepwise multiple regression revealed that five variables, accounting for 9% of the variance, were significantly related to alcohol consumption. Positively related were greater perceived risk of getting AIDS; obtaining income from spouse, family, or friend; living on the streets or in a shelter; or living in a hotel or boarding house. Negatively related was having an education level greater than high school. For those participants who reported having sex during the last 30 days, two variables were positively related to alcohol consumption and accounted for 17% of the variance: number of times used alcohol with sex and frequency of sex without a condom. In addition to identifying several demographic variables that are significantly related to alcohol consumption, the results document the relationship between alcohol consumption and unsafe sexual practices.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Unmet treatment needs of drug users in Alaska: correlates and societal costs.

This study assessed the unmet treatment needs of drug users in Anchorage, Alaska. It revealed that almost half of the drug users who desire treatment cannot secure it, largely for external reasons. The primary barrier to treatment was lack of availability of treatment slots, followed by excessive treatment costs and restrictive admission criteria. Unlike other studies, this investigation did not suggest that members of ethnic minority groups, women, and parenting women were disproportionately disadvantaged with regard to ability to secure treatment. However, substance abusers who also met criteria for a co-morbid psychiatric diagnosis other than substance abuse or dependence had more difficulty than their non-co-morbid peers in finding available treatment slots. Social, legal, and medical costs incurred by unsuccessful treatment seekers are outlined and suggest significant cost, as well as perpetuation of intergenerational cycles of violence and substance use.

Adolescent↗
PubMed1998

Cocaine smokers and injection drug users in Alaska: what distinguishes Native Americans from non-Native Americans?

Demographic and behavioral characteristics were modeled for distinguishing Native American drug users from non-Native American drug users in Anchorage, Alaska. Data were collected using a structured interview administered to participants (n = 1,091) who smoked cocaine, injected drugs, or both. Multivariate analyses were performed using logistic regression modeling. Four characteristics distinguish Native Americans (n = 223) from non-Native Americans (n = 868). Native Americans were more likely to have used marijuana at an earlier age and to have less than high school education; they were less likely to have ever used heroin and cocaine together, and to have used a condom during sex. Results are useful for administering interventions, data collection, and targeting hidden populations.

Adolescent↗
PubMed1996

Evaluating three reading tests for use with alcohol and other drug-abusing populations.

This study compared three reading tests commonly used in research for screening, descriptive, and educational purposes with alcohol and other drug-abusing individuals. To that end, 82 male and 41 female substance abusers were administered the Slosson Oral Reading Test-Revised, Woodcock Reading Mastery Test-Revised, and the Wide Range Achievement Test-Revised in random order. Results revealed that the tests have high concurrent validity, provide approximately the same grade-equivalent level scores, and yield raw scores that, when standardized, do not differ significantly from one another. However, if used for screening purposes, the three tests result in different proportions of subjects meeting specified criteria, particularly at lower grade levels. Specific test selection depends on the purpose of testing. For example, when the entire range of possible scores is of interest, the Woodcock Reading Mastery Test-Revised has a distinct advantage, because it has the widest range of grade-equivalent levels. Other considerations for test selection are discussed.

Achievement↗
PubMed1996

Assessing reading level of drug users for HIV and AIDS prevention purposes.

Using the short form of the Woodcock Reading Mastery Test-Revised and the reading subtest of the Wide Range Achievement Test-Revised, the reading abilities of 284 male and 128 female drug users from five sites across the United States were evaluated. All subjects were participants in a National Institute on Drug Abuse HIV/AIDS prevention project aimed at intravenous drug users and cocaine smokers. Results revealed differences in reading abilities among ethnic groups with Native and white subjects having significantly higher reading levels than Hispanic and black subjects. Significant site differences were revealed, with mean grade equivalent scores ranging from 2.7 to 10.1 grades. Across all subjects, the average grade equivalent reading level was 5.8 to 7.7, indicating that the subjects read below the level of 81.5% to 93% of the general population. We provide implications for development of educational materials that are accessible for this population.

Adult↗
PubMed1995

Reading abilities of drug users in Anchorage, Alaska.

Evaluated the reading abilities of 122 male and fifty-nine female intravenous and other drug users in Anchorage, Alaska. Reading abilities were assessed through the Reading subtest of the Wide Range Achievement Test-Revised and the short Form of the Woodcock Reading Mastery Test-Revised. Results indicated that men and Black subjects reported the highest levels of schooling completed. However, no differences were revealed across gender and ethnicity in actual reading levels. Among all subjects, the average reading ability was between 8.5 and 8.7 grade level. These scores place the average subject reading at a level lower than approximately 76 percent of the general population. Implications are provided for development of educational materials accessible for this population.

Adolescent↗
PubMed1995

Human tolerance and physiological responses to exercise while breathing oxygen at 2.0 ATA.

Multiple physiological functions were monitored in ten men who performed two 30-min periods of 150-W ergometer exercise during 120-min exposures to O2 at 2.0 ATA. There were no convulsions or electroencephalographic manifestations of increased excitability. Sequential measurements of peripheral visual fields, pulmonary mechanical function, mental performance, and cardiovascular function during the resting recovery after each of the two exercise periods were not detectably altered from pre-exercise control values. Pre- and post-exposure measurements of visual acuity, accommodation, pupil diameter, visual cortical activity, and retinal electrical activity also revealed no significant differences. While CNS symptoms were absent, average arterial PCO2 rose by about 5 mm Hg during both exercise periods. This finding was confirmed in six subjects who performed four 6-min periods of continuous exercise at 50, 100, 150, and 200 W while breathing O2 at 2.0 ATA. Average arterial PCO2 rose nearly linearly from 34.3 mm Hg at rest to 44.0 mm Hg at 200 W. Arterial PCO2-related increments in brain blood flow and PO2 may explain part or all of the known detrimental influence of exercise on CNS O2 tolerance.

Atmospheric Pressure↗
PubMed1993

Pharmacokinetics of exogenous epinephrine in critically ill children.

OBJECTIVES: This study was designed to determine the steady-state plasma concentrations and clearance rates of epinephrine in critically ill children, to examine if epinephrine pharmacokinetics conform to a linear model, and to compare epinephrine clearance rates with clearance rates of dopamine and dobutamine. DESIGN: This study was prospective, without intervention or control groups. SETTING: The pediatric ICUs of two tertiary care teaching hospitals. PATIENTS: All patients who were hemodynamically stable while requiring continuous epinephrine infusions were eligible for the study. INTERVENTIONS: Blood samples were taken at steady state and analyzed for epinephrine concentrations, as well as dopamine and dobutamine concentrations, if present, by high-pressure liquid chromatography with electrochemical detection. RESULTS: Plasma epinephrine concentrations during steady-state infusions of 0.03 to 0.2 micrograms/kg/min ranged from 670 to 9430 pg/mL (3660 to 51,490 pmol/L), with a mean of 4360 +/- 3090 pg/mL (23,810 +/- 16,870 pmol/L) and were linearly related to dose. Epinephrine clearance rates ranged from 15.6 to 79.2 mL/kg/min (mean 29.3 +/- 16.1) and were not dependent on steady-state plasma concentrations. Epinephrine clearance rate was in the same range as the clearance rates of dopamine (34.1 +/- 16.6) and dobutamine (35.9 +/- 27.8) and was linearly related to them (p < .005). CONCLUSIONS: Epinephrine infusions produce pharmacologic plasma concentrations of epinephrine in critically ill children. The plasma concentration of epinephrine correlates with the infusion rate, suggesting linear pharmacokinetics. Epinephrine clearance rates in critically ill children appear to be lower than the reported clearance rates in healthy adults. The clearance rates of two other inotropic catecholamines, dopamine and dobutamine, are significantly correlated with the clearance rate of epinephrine.

Adolescent↗
PubMed1993

Alcohol and heroin use patterns of narcotics addicts: gender and ethnic differences.

Data on lifetime alcohol and heroin use by 443 White and Chicano addicts of both genders were obtained from a sample of admissions to several Southern California methadone maintenance programs. Patterns of alcohol and heroin use were examined with respect to gender and ethnic differences. Repeated-measures MANOVA established an inverse pattern of alcohol and heroin use for all four groups, confirming and extending the findings of a previous study by the authors. With this additional evidence, the authors propose a compensatory model that explains the obtained inverse pattern of alcohol and heroin use and that may be suitable in examining concurrent or sequential use of other psychoactive substances in addition to alcohol. Significantly higher levels of heavy alcohol use were reported by Chicano than by White addicts. Overall findings indicate that after heroin addiction occurs, there is a convergence in patterns of substance use by both genders, although variations related to ethnicity persist, particularly for alcohol use.

Adolescent↗
PubMed1992

ECMO for infection.

Explore the source record for details and available documents.

Extracorporeal Membrane Oxygenation↗
PubMed1992

Comparability of the thermodilution cardiac output method: proximal injectate versus proximal infusion lumens.

In this study we examined the relationship between cardiac output (CO) measurements obtained from the proximal injectate lumen and the proximal infusion lumen of a thermodilution pulmonary artery catheter. The research was predicated on the belief that a strongly significant relationship would provide the clinician with an alternative lumen for measuring CO. Twenty-one subjects were selected by using a nonprobability convenience sampling method. With ice temperature injectate, four injections were performed into one lumen followed by four injections into the alternate lumen. CO values were computed with installed data management physiologic monitors. A Pearson's Product-Moment Correlation Coefficient was calculated, and the result verified a strong positive correlation between CO values (r = 0.96, p = less than 0.0001). Results of a paired t test demonstrated no statistically significant differences between CO means. These findings lend direction for minimizing the potential risk of catheter contamination associated with the manipulation of intravenous lines containing vasoactive medications. It also may save time for the critical care clinician who is trying to balance tasks such as CO measurements and titration of vasoactive or inotropic medications.

Adult↗
PubMed1989

Colonic mucosectomy using laser photodynamic therapy.

Photodynamic therapy (PDT) involves photosensitizing tissue and then activating it with monochromatic light, causing necrosis. Precise control of the extent of injury should be possible by varying the energy density of the light applied to the target tissue. We tested the sensitivity of colonic tissue to PDT by injecting 10 mg/kg Photofrin II intraperitoneally in 10 rats. After 24 hr the left colon was opened and cleansed. A 1.0-cm2 area of mucosa was exposed to 630 nm (red) light produced by an argon-pumped dye laser. Pairs of rats were treated with energy densities of either 10, 20, 40, 60, or 80 J/cm2, controlled by varying exposure times. After 48 hr, we sacrificed the rats and fixed, sectioned, and stained the left colons. The depth of injury was measured with an ocular micrometer and expressed as a percentage of normal bowel wall thickness. A curve was fit to the data points by computerized nonlinear regression. The relationship between depth of injury (Y) and energy density (X) was found to fit the equation Y = 1 - aebx, where constants a = 1.15 and b = -0.0353, (R2 = 0.93, P less than 0.001). The relationship between injury and energy density is biphasic, rising rapidly from 0 to 40 J/cm2 and more slowly after this point, suggesting that colonic mucosa is more sensitive to PDT than muscularis, providing a margin of safety against perforation. Bowel perforation did not occur in this study but is predicted by extrapolation for energy densities of 100 J/cm2 or greater. These data indicate that photodynamic colonic mucosectomy is possible.

Animals↗
PubMed1989

Substance use among high school students in relation to school characteristics.

This research relates current use by 11th grade students of 17 psychoactive substances and age of first use and intoxication to characteristics of high schools in which they are enrolled. The 2,471 11th grade students surveyed were enrolled in a representative sample of 44 California high schools. Correlations between schools based on twelve characteristics (total 12th grade achievement scores, SES, percent various ethnic groups, etc.) were analyzed by means of a complete linkage cluster analysis. Three clusters of schools were identified. Frequency of use of alcohol, marijuana, cocaine, and other substances as well as polydrug use and age of first alcohol use were found to differ significantly between schools in different clusters. In general, substance use was highest in rural or small town, predominantly white high schools with relatively low enrollments, second highest in large, high SES, predominantly white schools, and lowest in large, low SES, predominantly minority high schools. Four hypotheses relating school characteristics and substance use suggested by these findings are proposed.

Achievement↗