Search PubMed⌕ Search

Biomedical subjects

D Walter

Publications and source records attributed to D Walter.

At least 37 records · Page 2Linked to original sources
PubMed1994

Impulsiveness and subjective effects of intravenous cocaine administration in the laboratory.

Cardiovascular and subjective responses to placebo and 40-mg intravenous (iv) cocaine injections were measured in 29 male iv cocaine users: most subjects received each of these injections on two separate occasions. Most of the subjects also completed various measures of psychopathology and personality. Although the small sample size made any conclusions tentative, an expected significant association between impulsivity and subjective euphoria following 40-mg cocaine administration was obtained, whereas associations of personality measures with cardiovascular responses to cocaine administration were inconsistent.

Adult↗
PubMed1994

Technique of endoscopic mediastinal dissection of the oesophagus.

Conventional transhiatal dissection of the oesophagus is usually performed without visual control. The attendant danger of this is that complications such as bleeding and tracheal lesions may be overlooked. This problem can be avoided by the use of an endoscopic operation system. This report describes a new technique of endoscopic microsurgical dissection of the oesophagus (EMDOE) and the results of the first 35 cases. Under visual control with a specially designed mediastinoscope the soft tissue surrounding the oesophagus is carefully dissected, and the oesophageal blood vessels can be safely exposed, coagulated and divided. The dissection begins cervically and proceeds along the oesophagus down to the oesophagocardiac junction. A simultaneously working abdominal team helps remove the oesophagus, which is then replaced by a stomach tube. Although the method is still under evaluation, results to date have been especially good for small distal tumors, especially adenocarcinomas.

Adenocarcinoma↗
PubMed1992

Technical Points in Vertical Gastroplasty for Morbid Obesity.

The success of vertical gastroplasty may be jeopardized by gastric leakage or ulceration due to failure of the technique. Reports of band erosion and staple-line leakage have led us to seek technical improvements to reduce technical failures. We describe a modification to the technique of band placement and a manoeuvre to aid the placement of staples when the TA90B staple gun is used.

Journal Article↗
PubMed1991

A controlled trial of synthetic surfactant in infants weighing 1250 g or more with respiratory distress syndrome. The American Exosurf Neonatal Study Group I, and the Canadian Exosurf Neonatal Study Group.

BACKGROUND: Surfactant-replacement therapy is now recognized as a life-saving and safe intervention in small premature infants, but there is little evidence concerning its risks and benefits in larger premature infants. METHODS: We conducted a placebo-controlled, blinded trial in 1237 infants with respiratory distress who were enrolled at 23 hospitals in the United States and 13 hospitals in Canada. At entry all the infants weighed at least 1250 g, were receiving mechanical ventilation, and had a ratio of arterial to alveolar oxygen tension below 0.22. The initial dose of either the synthetic surfactant (Exosurf, 5 ml per kilogram of body weight) or air (the placebo) was administered less than 24 hours after birth, with a second dose given 12 hours later. A total of 614 infants were assigned to receive surfactant, and 623 to receive placebo. RESULTS: Fewer infants in the surfactant group than in the placebo group died before 28 days of age or survived at 28 days with bronchopulmonary dysplasia (7 percent vs. 12 percent, P = 0.002). In the first 28 days of life, there were fewer deaths due to respiratory distress syndrome in the surfactant group (1 percent vs. 3 percent, P = 0.043), lower overall neonatal mortality (4 percent vs. 7 percent, P = 0.04), and a lower incidence of bronchopulmonary dysplasia (3 percent vs. 6 percent, P = 0.008). There was also a significantly lower incidence of pulmonary air leaks, intraventricular hemorrhage, patent ductus arteriosus, seizures, hypotension, and pulmonary hypertension in the surfactant group. The infants treated with surfactant were weaned from oxygen and mechanical ventilation significantly sooner than those given placebo, and they less often required high-frequency ventilation or extracorporeal membrane oxygenation. The primary side effect observed more frequently among the infants who received surfactant treatment was pulmonary hemorrhage (six infants vs. one infant, P = 0.055). CONCLUSIONS: In infants weighing at least 1250 g at birth who have respiratory distress syndrome, treatment with two doses of synthetic surfactant improves survival and reduces perinatal morbidity.

Birth Weight↗
PubMed1990

Self-report vs. laboratory measures of aggression as predictors of substance abuse.

Measures of aggressive behavior, antisocial personality, criminality, and impulsivity were obtained on a sample of 85 drug abusing volunteers for studies at the Addiction Research Center in Baltimore. Measures included the Buss-Durkee Hostility Inventory, Diagnostic Interview Schedule Antisocial Personality Disorder diagnosis, Elliott-Huizinga Lifetime Events Scale, Eysenck's Impulsiveness-Venturesomeness-Empathy scales, and a laboratory measure of aggression patterned after the Buss 'aggression machine'. All of the self-report measures of aggression and antisocial personality were moderately correlated with each other, but did not correlate with the laboratory aggression measure. This laboratory measure, nevertheless, made a significant contribution to the prediction of certain substance abuse diagnoses over and above the contributions of the other measures.

Adult↗
PubMed1990

Subject selection bias in alcoholics volunteering for a treatment study.

Baseline differences in alcoholism problem severity were compared between alcoholics who did and did not volunteer to participate in a treatment effectiveness study. A positive relationship was found between self-reports of alcohol-related problems and the degree of research participation. Group differences were also revealed in the rate of treatment completion. Possible explanations and solutions for this volunteer bias are discussed.

Adult↗
PubMed1990

The prediction of drug dependence from expectancy for hostility while intoxicated.

Three hundred seventy-one male substance-abusing volunteers for drug studies were administered the Buss-Durkee Hostility Inventory (B-D). One hundred nineteen of these subjects were readministered the B-D with the instruction to answer the items in terms of their behavior while drinking alcohol, with 67 of these subjects also completing a heroin use condition. Expectancies for hostility under alcohol or heroin were generally uncorrelated with other measures of personality, psychopathology, antisocial personality, impulsiveness, or criminality; but expectancies for hostility under alcohol were predictive of diagnoses of alcohol, opioid, and marijuana abuse and dependence over and above the influence of these other measures.

Adult↗
PubMed1989

Correlates of self-reported early childhood aggression in subjects volunteering for drug studies.

The construct validity of a retrospective self-report measure of early childhood aggression, the Early Experience Questionnaire (EEQ), was assessed in a sample of substance abusing volunteers for drug studies at a research center in Baltimore. In contrast to the diagnosis of Antisocial Personality Disorder (APD), EEQ scores were not only associated with adult aggression, criminality, and substance abuse, but were also highly correlated with a cluster of measures reflecting emotionally reactive impulsivity. Correlations of the EEQ with the Minnesota Multiphasic Personality Inventory confirmed earlier findings obtained on a sample of alcoholics. Over and above the predictive influence of APD, early childhood aggression had some predictive influence on the incidence and severity of substance abuse but a substantial influence on the prediction of criminality.

Adult↗
PubMed1989

Evaluation of treatment for cocaine dependence.

1. At the Philadelphia VA Medical Center, veterans applying for treatment of cocaine dependence were significantly different from applicants dependent on opiates or alcohol without cocaine. The cocaine dependent patients were almost all black and they were mostly employed. Few were involved in crime and, for most, this was the first course of substance abuse treatment. Their use of cocaine began within the past three years and they had relatively few psychiatric, medical, employment or family problems when compared with other applicants for substance abuse treatment. 2. Completion rate for a course of outpatient treatment for cocaine dependence varies from a low of 37% in the general Day Treatment Program to 76% in a special Behavioral Treatment Program and 78% among methadone patients receiving an additional medication for cocaine dependence. Completion of a 28 day course of inpatient treatment was 86% whether the patient selected inpatient care or was assigned to it on a random basis. 3. Those outpatients who remained in treatment generally did well and refrained from cocaine use even during the course of outpatient, either day hospital treatment or behavioral treatment. When both inpatients and outpatients were re-examined four months after beginning treatment, there was significant improvement on almost all ASI categories. Both drop-outs and completers were re-examined. Despite the significantly greater completion rate for the patients assigned to inpatient treatment, both groups showed equal levels of improvements at the 4-month follow up point. 4. These preliminary results from five different treatment populations suggest that cocaine dependent patients can be engaged in treatment and that significant improvement is possible.

Adult↗
PubMed1982

Kainic acid alters cholinergic responses in the rat retina: a 2-deoxyglucose study.

Intraocular injections of the neuroexcitatory toxin, kainic acid, did not alter the output of the retinal ganglion cells, as determined by the rate of glucose use in the stratum griseum superficialis of the superior colliculus. However, significant differences were observed in cholinergic interactions of the ganglion cells after kainic acid treatment. Intraocular injection of kainic acid prevented the increase in the stratum griseum superficialis activity typically produced by systemic injection of the acetylcholinesterase inhibitor diisopropylfluorophosphate (DFP). In addition, the retinal ganglion cells were strikingly sensitive to intraocular injections of acetylcholine 1 week after exposure to kainic acid, as reflected in the marked increased glucose utilization in the stratum griseum superficialis. This responsiveness to acetylcholine may be entirely due to the 80% decrease in acetylcholinesterase in the retina observed 1 week after kainic acid exposure or in part to a supersensitivity of the ganglion cells following the period of acetylcholine depletion.

Acetylcholine↗