Biomedical subjects
Publications and source records attributed to N Hymowitz.
A mail survey of pediatrician practices and procedures for the modification of environmental tobacco smoke (ETS) and cigarette smoking in patients and parents was mailed to pediatricians. Results indicated that a large proportion of pediatricians address the issue of ETS and cigarette smoking.
Paterson COMMIT is an effort to combat cigarette smoking. The theme for 1994 was "The Smoke-Free Household," and programs were aimed at altering community norms and helping smokers quit. Paterson COMMIT is a successful demonstration of what a community can accomplish.
BACKGROUND: The results of MRFIT smoking intervention program are presented for the 4,103 special intervention and 4,091 usual care men who reported smoking cigarettes at the first screening visit. RESULTS: Among the special intervention men, the reported cessation rate increased from 43.1% at 12 months to 48.9% at 72 months. The reported cessation rate among the usual care men increased from 13.5% at 12 months to 28.8% at 72 months. Among smokers who reported cessation at 72 months, 51.3% of special intervention men and 22.7% of usual care men had quit smoking within the first year and remained abstinent thereafter. Average thiocyanate and expired-air carbon monoxide served as objective measures of smoking and were significantly lower among the special intervention men than among the usual care men over the entire follow-up period. The reported cessation rates at 72 months varied according to initial levels of smoking. Smokers reporting 1-19 cigarettes per day at entry were more likely to quit than heavier smokers. For each category of smoking at entry (1-19, 20-39, and 40 or more cigarettes per day) significantly more special intervention than usual care smokers reported cessation. CONCLUSION: These results indicate that the MRFIT smoking intervention program was successful in promoting early cigarette smoking cessation and maintaining cessation over the entire trial for a large percentage of cigarette smokers.
BACKGROUND: Data on smoking cessation and relapse for 6 yers of the Multiple Risk Factor Intervention Trial were evaluated in univariate and multivariate analyses to determine the relationship between variables measured at the beginning of the trial and smoking cessation and relapse for special intervention and usual care participants. RESULTS: The variables positively associated with smoking cessation in both the SI and the UC groups included age, education, and past success in quitting; there was a negative association with the number of cigarettes smoked per day. The expectation of quitting was positively associated with cessation in the special intervention group only, while life events, alcohol, and the presence of a wife who smokes were significant predictors of reduced cessation for the usual care group. The special intervention program may have overcome obstacles which interfered with cessation among the usual care participants. Associations with relapse were generally stronger in the usual care group than in the special intervention group. For usual care participants, multivariate analyses showed that education, past success in quitting smoking, alcohol, and life events were associated with relapse rates. For special intervention participants, only alcohol emerged as a significant predictor. Conclusion. The data are relevant in terms of factors that govern smoking cessation and relapse for adult smokers who take part in formal intervention programs and for those who are left to modify their behavior on their own.
Maximizing the potential of worksites for smoking intervention remains elusive. We hypothesized that long-term effectiveness of group intervention would be enhanced when offered within an "enriched milieu" (full program) compared with relative isolation (group only). The data failed to support the hypothesis. Although sustained abstinence rates were higher at full-program sites (50%) than at group-only sites (44%), the difference did not achieve statistical significance. Initial (35% vs. 47%) and 12-month (18% vs. 22%) quit rates at full-program and group-only sites also failed to demonstrate the "benefit" of the "enriched milieu."
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Rats were trained to press a lever under a multiple fixed-ratio 25 fixed-interval 50-second (FR25 FI50-sec) schedule of food reinforcement. Soman, 70-90 micrograms/kg, s.c., suppressed response rates in both components, with a slightly greater effect in the FI schedule. The pattern of responding under the FI schedule, however, was maintained until lever-pressing was nearly completely suppressed. At the highest doses, soman occasionally caused tremors or mild tonic seizures with hindlimb abduction. The suppression of response rate was correlated with inhibition of acetylcholinesterase (AChE) in all brain regions examined: cortex, striatum, hippocampus, hypothalamus and brainstem. Cortical AChE was inhibited to the highest degree, while striatal AChE was most resistant to inhibition by soman.
Rats were trained to press a lever under a multiple Fixed-Ratio 25 Fixed-Interval 50-second schedule of food reinforcement. Subcutaneous injection of soman, 80 micrograms/kg, suppressed responding under both schedules and inhibited acetylcholinesterase (AChE) in the brain. AChE activity in the gastrointestinal tract was not significantly inhibited. In contrast, i.p. injection of either soman (10-40 micrograms/kg), neostigmine (75 micrograms/kg) or DFP (350 micrograms/kg) caused marked suppression of behavior and AChE activity of the gut, without affecting brain AChE. These doses caused marked increases in peristaltic activity and likely caused gastrointestinal spasm. Injection of DFP, 500 micrograms/kg, s.c., inhibited AChE in both the brain and gut. The results indicate that inhibition of AChE in the gastrointestinal tract by certain anticholinesterase agents may be involved in the behavioral effects attributed to these drugs.
Intraperitoneal (IP) administration of the acetylcholinesterase inhibitor, soman (10-40 micrograms/kg), suppressed in a dose-related manner response rates in rats maintained under a multiple fixed-interval 50-s fixed-ratio 25 schedule of food delivery. Chronic administration of soman at weekly intervals resulted in tolerance to the response. When soman administration was separated by 2-5 weeks in individual rats, the suppressive effects of the agent again became apparent. Analysis of acetylcholinesterase activity revealed that enzyme inhibition was limited to gastrointestinal areas near the site of injection. There was no significant effect on brain acetylcholinesterase even following IP injection of doses which completely suppressed responding. The IP route may be useful for studying tolerance and other chronic effects of soman without producing generalized toxicity.
N-(4-diethylamino-2-butynyl)-succinimide, or DKJ-21, is a muscarinic receptor antagonist with a high degree of selectivity for the central nervous system. In the present study of 6 rats maintained under a fixed-interval 50-sec schedule of food reinforcement, atropine and methylatropine reduced responding in a dose dependent manner, while DKJ-21 had little or no effect. Our findings suggest that the suppression caused by atropine and methylatropine may be the result of the dry mouth induced by these agents. Doses of DKJ-21 which had no effect on schedule performance antagonized the rate-lowering effects of physostigmine in all of the animals. Neither atropine nor methylatropine consistently antagonized the inhibitory effects of physostigmine. Some antagonism may be inferred, however, from the findings that response rates were suppressed less by combinations of atropine and physostigmine than by either drug alone.
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While the effects of benzodiazepines on punished responding (response-dependent shock) are straightforward and unambiguous, their effects on behavior suppressed by response-independent shock are conflicting and inconsistent. Some investigators reported that benzodiazepines either have no effect on, or suppress further, responding during response-independent shock, while others reported that benzodiazepines enhance response rates during independent shock delivery in the same manner as during dependent shock. The present study compared the effects of diazepam on rates of lever pressing maintained by a variable-interval 35-sec schedule of food delivery in rats exposed alternately to fixed-interval 180 sec (response-dependent) and fixed-time 180 sec (response-independent) schedules of shock delivery. Diazepam increased punished responding in a dose-dependent manner for each animal. "Rate-dependency," degree of suppression and presence of external stimuli influenced rate-enhancement by the drug. Effects of diazepam on responding suppressed by response-independent shock were inconsistent, with two animals revealing rate enhancement comparable to punished responding, and two others revealing further increases in response suppression. Reasons for the differential effects of diazepam on response-rates suppressed by the two forms of shock delivery remain obscure, although the basic phenomenon seems to be real and not merely an artifact of "rate-dependency."
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Schedule-controlled lever pressing and schedule-induced licking were studied in rats under a multiple fixed-interval fixed-interval schedule of food reinforcement upon which was superimposed a multiple variable-time variable-time schedule of electric-shock delivery. Shocks were signaled in one component of the multiple schedule and unsignaled in the other. The effects of diazepam upon the suppression of behavior during the signal (conditioned suppression) and during signaled and unsignaled shock (differential suppression) were studied under several shock intensities (Experiment 1) and at increased body weight (Experiment 2). In each study, diazepam led to dose-dependent increases in the rate of pressing and licking during signaled and unsignaled shock, but had little effect on conditioned suppression. the rate-enhancing effects of diazepam depended upon the intensity of shock, nature of the response, and whether or not shocks were signaled. The data was discussed in terms of (1) implications for understanding the effects of signaled and unsignaled shock on behavior, (2) the effects of diazepam on behavior suppressed by response-independent shock, and (3) comparison between operant and schedule-induced behavior.