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Biomedical subjects

D G Fisher

Publications and source records attributed to D G Fisher.

16 recordsLinked to original sources
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↗
PubMed1989

Alcohol use by heroin addicts: evidence for an inverse relationship. A study of methadone maintenance and drug-free treatment samples.

This study examines the relationship between the patterns of use of alcohol and heroin by narcotics addicts, and evaluates the hypothesis--frequently reported during methadone maintenance--that this form of treatment can be causally implicated in an increased consumption of alcohol. Data were obtained on lifetime patterns of alcohol and heroin use of 375 Anglo and Chicano male addicts sampled from two treatment sources: the nonmethadone (drug-free) California Civil Addict Program (CAP) and several Southern California Methadone Maintenance (MM) programs. Repeated-measures MANOVAs revealed that alcohol and heroin consumption were inversely related throughout the addicts' careers. This pattern was evident in the addiction, treatment, and postdischarge stages of Anglo and Chicano addict careers, in both the CAP and MM samples. Consequently, the authors reject the hypothesis that increased alcohol consumption is caused solely by addicts' participation in methadone maintenance treatment. Rather, the findings suggest that addicts' alcohol use during methadone treatment reflects a lifetime pattern of increased alcohol use following any decline in heroin intake.

Adult↗
PubMed1989

The MMPI profiles of narcotics addicts. I. A review of the literature.

This paper reviews three approaches to using the Minnesota Multiphasic Personality Inventory (MMPI) in the assessment of narcotics addicts' psychopathology. Two approaches examine the relationship of MMPI profiles to established sociodemographic or psychiatric typologies; the third pertains solely to MMPI-derived personality typologies. Findings from the research literature are presented and their implications for clinical assessment and treatment are discussed.

Heroin Dependence↗
PubMed1989

The MMPI profiles of narcotics addicts. II. Ethnic and criminal history effects.

Data from 240 male heroin addicts admitted to the California Civil Addict Program (CAP) were analyzed to determine if incarceration before or after first narcotics use--a behavioral marker termed "sequence"--was significantly related to MMPI profile scores. Furthermore, this relationship was examined separately for Anglos and Chicanos. Results indicate that those Anglo addicts who had been incarcerated before they first used narcotics had significantly elevated scores for Paranoia (Pa) and Schizophrenia (Sc), two scales of the psychotic triad. A significant sequence-by-ethnicity interaction was found, in which the sequence effect was not manifested in Chicano addicts.

Adolescent↗
PubMed1987

Survival analysis in drug program evaluation. Part I. Overall program effectiveness.

Survivorship analysis is a statistical technique used here in a summative evaluation that compares outcome data from multiple-site methadone maintenance programs in three California counties. Multiple outcome measures were obtained from retrospective interviews with 297 heroin addicts 6-8 years after admission to treatment. These measures were rates of retention, incarceration, addiction, crime, dealing, and loss of employment. Survival curves for all six measures are consistent in showing that Los Angeles County had the best outcomes, followed by San Bernardino County and then Orange County.

Adult↗
PubMed1987

Survival analysis in drug program evaluation. Part II. Partitioning treatment effects.

Survivorship analysis is applied to both a summative process (during treatment) and a summative outcome (after discharge) evaluation comparing data obtained from 297 admissions to multiple-site methadone maintenance programs in three California counties. Measures included rates of retention, incarceration, addiction, crime, dealing, and loss of employment. In order to take full advantage of the multiple outcome measures that were used, a method for within-subject simultaneous consideration of all outcome measures is presented. This method is an adaptation of the Friedman nonparametric analysis of variance and a Bonferroni post hoc comparison of the mean ranks.

Crime↗
PubMed1982

Effects of spatial context during acquisition on the recall of attributive information.

We found that learners were sensitive to the spatial context in which various information was obtained and that they could use it symbolically to aid recall even when spatial cues were not available during testing. In three experiments, televised and purely aural statements made by various speakers were presented at distinct locations in the recipient's immediate surroundings. This was found to increase attributive recall compared to (a) all information sources in a single place, (b) information sources in several places but with place not consistently linked with information sources, and (c) use of a nonspatial stimulus context consistently associated with information source, such as the physical appearance of announcers. Theoretically, we conclude, with Hasher and Zacks, the place provides especially privileged cues and that not all content-correlated background stimuli are equipotent cues in associative learning. Practically, we recommend that in order to remember who said what, it helps to have speakers in separate and distinct places.

Cues↗
PubMed1976

The adhesion of film coatings to tablet surfaces--instrumentation and preliminary evaluation.

The strength of the adhesive bond between a film coating and a tablet surface has been studied using a specially designed tensile testing apparatus. The adhesion has been taken as the force required to remove the film from unit area of the tablet surface and has been shown to be dependent on the compression pressure used to prepare the tablet and on changes in the film formulation. Although plasticizers did not show any significant effect on the adhesion of a hydroxypropyl methylcellulose film, a reduction of 45% was found on the addition of 10% w/w titanium dioxide.

Adhesiveness↗