Society for Research on Nicotine and Tobacco

The proceedings of the second annual scientific conference of the Society for Research on Nicotine and Tobacco are summarized. The goal of the annual conference was to disseminate information about ongoing nicotine research from biological, behavioral and social perspectives. Data were presented describing our current understanding of the structure and function of neuronal nicotinic acetylcholine receptors, by which nicotine exerts most, if not all, of its effects in the brain. The conformational complexity of receptor subunits expressed in different brain areas contributes significantly to the complexity of responses observed to nicotinic agonists. Nicotine is being developed as a medication that might be used to maintain smoking cessation and to treat various medical diseases. The potential toxicity of nicotine, apart from cigarette smoking, is an important variable in assessing the benefits and risks of such therapeutic applications. The risks of nicotine-containing medications appear to be far less than those associated with tobacco use. Recent data indicate that cigarette smoking is increasing among youth in the United States. Adolescent smokers are interested in quitting and make frequent quit attempts, but are usually not successful. Effective methods are needed to manage adolescent smokers before they become heavily addicted. Nicotine replacement as a pharmacological treatment for smoking cessation has made a significant contribution in improving quit rates. New medications have been developed that target specific populations of smokers.     

How does the pitch and pattern of a signal affect auditory arousal thresholds?

How arousal thresholds vary with different sounds is a critical issue for emergency awakenings, especially as sleepers are dying in fires despite having a working smoke alarm. Previous research shows that the current high-pitched (3000+ Hz) smoke alarm signal is significantly less effective than an alternative signal, the 520 Hz square wave, in all populations tested. However, as the number of sounds tested has been small further research is needed. Here we measured auditory arousal thresholds (AATs) across signals with a range of characteristics to determine the most effective waking signal. Thirty-nine young adults participated over three nights. In Part A, nine signals were presented in stage 4 sleep with ascending decibel levels. Signals were short beeps in the low- to mid-frequency range with different spectral complexities: square waves, pure tones, whoops and white noise. Part B manipulated temporal patterns, inserting silences of 0, 10 and 21 s after each 12 s of beeps. It was found that the low-frequency (400 and 520 Hz) square waves yielded significantly lower AATs than the alternatives. A trend was found across the three temporal manipulations, with a 10 s intervening silence showing some advantage. These findings support earlier research indicating that the best sound for awakening from deep sleep is a low-frequency square wave. It is argued that the signal with the lowest response threshold when awake may be the same as the most arousing signal when asleep, especially where the sleeper processes the signal as meaningful.     

Factors affecting the uptake of screening for neural tube defect

Summary. A questionnaire concerning pregnant women's knowledge of, and attitudes to, serum alpha fetoprotein (AFP) screening for spina bifida was sent to all pregnant women receiving a health education leaflet on AFP screening who booked at the Birmingham Maternity Hospital in the first quarter of 1984. The majority said that they would accept the test, and subsequently did so. This suggests that low uptake of the test is not a result of patients' resistance, and the results indicated that the provision of early information about the test is likely to improve uptake and decrease anxiety. With the increasing clinical usefulness of the AFP test, routine screening of pregnant women with an 'opt-out' system is becoming clinically desirable, and the survey suggests that it would be acceptable to the patients.     

Effect of maternal age on autosomal trisomies

The effect of maternal age on the genesis of trisomy was studied by comparing data from 362 trisomic and 790 chromosomally normal spontaneous abortions. As a group the trisomies were associated with a substantial increase in maternal age but there were considerable differences in the magnitude of the effect for different trisomies. The effect of increasing maternal age was most pronounced for trisomies involving the small chromosomes, both acrocentric and non-acrocentric. However, trisomy 16 was conspicuously different from trisomies for all the other small chromosomes, both in the reduced importance of increased maternal age and in the high frequency with which it occurred. The effect of increasing maternal age on trisomies for chromosomes in groups A, B and C was less clear than that for the small chromosomes. However, the evidence suggested that trisomy for these chromosomes was associated with a moderate increase in maternal age.
It was suggested that the maternal age-dependent trisomies might result from precocious disjunction of the bivalents and random segregation of the resulting univalents, a process which would affect chromosomes with the fewest number of chiasmata and which might be more prevalent in oocytes of older women. It was further suggested that true non-disjunction, that is, the failure of bivalents to separate at anaphase, might also result in the production of trisomies. This process might be independent of, or only slightly influenced by, increasing maternal age but be affected by the presence of large blocks of heterochromatin.     

Breast-milk Jaundice

The syndrome of breast-milk jaundice, which often results in cessation of breastfeeding, maternal anxiety, and guilt, may be increasing. Research to date on pregnanediol, increased lipase, and free fatty acids as the causes of breast milk jaundice is reviewed. Variations in current treatment are presented and nursing measures supportive of parents and continued breastfeeding are provided.