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Biomedical subjects

K Downey

Publications and source records attributed to K Downey.

8 recordsLinked to original sources

Predicting the emergence and persistence of alcohol dependence in young adults: the role of expectancy and other risk factors.

The relationship of alcohol outcome expectancies and other risk factors: demographic, personality, and affectivity, to alcohol dependence status was examined over a 3.5-year interval in 1,007 young adults. Lifetime prevalence of alcohol dependence was 18.1% at baseline. Of persons classified as current alcohol dependent at baseline, 66.9% experienced remission at the 3.5-year follow-up. Of persons classified as remitted alcohol dependent at baseline, 11.3% were current alcohol dependent at the 3.5-year follow-up. At follow-up, 5% of persons with no history of alcohol dependence at baseline met criteria for current alcohol dependence. Male gender, higher extraversion, and lower positive affect scores predicted emergent current alcohol dependence at the 3.5-year interval. Persistent current alcohol dependence was predicted by the expectation of improved social and sexual experiences following alcohol use. The findings suggest that positive expectancies may be an important factor in persistence of alcohol dependence and that their modification may enhance treatment of alcohol dependence in young adults.

Adult↗

Alexithymia and negative affect: relationship to cigarette smoking, nicotine dependence, and smoking cessation.

Alexithymia is associated with substance abuse and may interfere with successful psychotherapy. Alexithymia's relation to smoking, nicotine dependence, and smoking cessation therapy is unknown, and potentially overlaps with negative affect. Three studies addressed the relations between alexithymia, negative affect, and smoking. In Study 1, 67 young adult smokers were more depressed than 370 past or never smokers, but no different on the Toronto Alexithymia Scale total or subscale scores. In Study 2, negative affect--but not alexithymia--was related to greater nicotine dependence among 99 chronic smokers. In Study 3, alexithymia tended to predict increased patient participation in cognitive-behavioral therapy for smoking; low nicotine dependence--but neither alexithymia nor negative affect--predicted abstinence from smoking at treatment end. Alexithymia appears to be independent of negative affect and unrelated to cigarette smoking or nicotine dependence, suggesting that the affect regulation deficits in alexithymia play a negligible role in nicotine addiction.

Adolescent↗

The interaction between chronic oral slow-release theophylline and single-dose intravenous erythromycin.

Eight volunteers were each given 300 mg of erythromycin lactobionate by i.v. infusion over 15 min in the presence and absence of chronic dosing with slow-release theophylline. Pharmacokinetic profiles were obtained for theophylline in the presence and absence of erythromycin and for erythromycin in the presence and absence of theophylline. A very small, clinically unimportant, but statistically significant increase occurred in mean (+/- S.E.M.) serum theophylline concentration from 4.9 +/- 0.3 mg/l to 5.2 +/- 0.3 mg/l in the presence of erythromycin (P = less than 0.01). The theophylline pharmacokinetic parameters did not change significantly. The only changes in erythromycin pharmacokinetics were an increase in the renal excretion (0-12 h) from 5.5 +/- 4.0 mg to 11.2 +/- 6.0 mg (P less than 0.03) and an increase in renal clearance (0-2 h) from 9.0 +/- 6.0 ml/min to 21.6 +/- 15 ml/min (P less than 0.05) in the presence of theophylline.

Administration, Oral↗

Should erythromycin dose be altered in haemodialysis patients?

Erythromycin kinetics were studied in 17 patients with end stage renal failure treated with maintenance haemodialysis and 9 normal volunteers to discover if dialysis patients needed a modified dose. The elimination half life in dialysis patients (on dialysis days) was similar to that reported in normal subjects. Only small amounts of drug appeared in the dialysate, no patient loosing more than 9 mg in one dialysis. Both patients and volunteers had similar plasma concentrations 8 h after the end of a 5-day course. Protein-binding did not change significantly during dialysis and was similar to that reported in normal subjects. We conclude that dialysis patients requiring 1.5 g of erythromycin stearate daily or less can be given normal doses.

Adult↗

The effect of vitamin C on the rapid induction of aortic changes in rabbits.

Male rabbits were injected intraperitoneally for five consecutive days with one of the following: (A) 0.3 ml/kg dimethyl ethylene glycol (solvent); (B) 40 mg/kg cholesterol and 8 mg/kg ergocalciferol in solvent; (C) same regimen as B with the addition of 150 mg/kg ascorbic acid in water. Daily blood samples were taken for determination of cholesterol and triglycerides, and for lipoprotein electrophoresis. After 5 days of injections, histological sections were made of the aorta at the arch. After 5 days, group B, as compared with group A, had higher serum cholesterol (150 ng/dl vs. 50 mg/dl, p less than 0.005), higher serum triglycerides (650 mg/dl vs. 150 mg/dl, p less than 0.01), and lower high-density lipoprotein (16% vs. 35%, p less than 0.05). On autopsy, discontinuous elastic fibers and intimal damage were seen in sections of the aortas from group B, but not from group A. After 5 days, group C had control levels of cholesterol (55 mg/dl) and triglycerides (160 mg/dl), and no significant difference from the control lipoprotein profile. Injections of cholesterol alone showed a slight induction of aortic lesions and blood chemistry changes. No alterations in these parameters were induced by ergocalciferol alone. The data indicate a prophylactic effect of vitamin C on the biochemical and histological changes rapidly induced by cholesterol and ergocalciferol.

Animals↗

Tonsillectomy and infectious mononucleosis.

Tonsillar tissue may be the primary site of infection with Epstein-Barr virus (EBV), the etiologic agent of classical infectious mononucleosis (IM). Therefore, a retrospective study of the association between tonsillectomy and IM was performed in a college student population. In the first part of the study, tonsillectomy rates were compared between 164 IM-positive students and 164 student controls who attended UCLA in 1972-1975. Although it was determined that the development of IM during college years was statistically less commin in tonsillectomized students, the difference was not inordinately large and probably had no significant biologic meaning. The authors speculate that the difference was due to the greater likelihood, and greater yield, in considering the diagnosis of IM in young adults with enlarged, inflamed tonsils. In support of this is the fact that IM-positive students who had received a prior tonsillectomy usually had the surgical procedure performed at a younger age than the control group. Conceivably, tonsillar ablation in the very young is more liable to result in incomplete removal and eventual regrowth of this tissue. Indeed, six IM-positive students who had received a tonsillectomy at six years of age or less were found to have exudate in tonsillar fossae or pillars during their IM episode. In the second part of the study, clinical and laboratory measures were found to be similar between a larger group of IM-positive students with or without a history of prior tonsillectomy.

Adolescent↗

Urinary cortisol excretion rates and anxiety in normal 1-year-old infants.

Urinary cortisol excretion rates were determined for each voiding during 8 hours on 3 days for 20 infants. The first day served as the control. On the second day stress was imposed by having the mother leave the infant for an hour. On a third day the child was stimulated by novel toys and socialization for an hour in the mother's presence. There was no significant difference between mean cortisol excretion rates on control and stress days. Variability in cortisol levels was significantly greater on the day of stress than on the other 2 days. Ratings of separation anxiety and levels of cortisol excreted 40 to 160 min after the imposed stress were positively correlated (r = 0.46, P less than 0.01). Cortisol levels also differentiated between anxious infants who were agitated from those who were withdrawn. No altered levels of cortisol were associated with excitement.

Anxiety, Separation↗