Social influences and constraints on the initiation and cessation of adolescent tobacco use

This research examines the viability of a theoretical perspective which combines social bonding theory and differential association theory in explaining the initiation and cessation of adolescent tobacco use. Three-year panel data collected from seventh- to twelfth-grade adolescents were analyzed using differences in means tests and discriminant analysis. The findings indicate overall support for the theoretical model in discriminating between (1) initiators and stable nonsmokers and (2) cessators and stable smokers. However, there were some differences in the variables found to be important at each stage of adolescent smoking. Commitment to education, attachment to father and mother, and association with female smoking friends were the most effective discriminators for the initiation stage, while attachment to father, beliefs, and association with both male and female smoking friends were important for the cessation stage. Findings are also discussed for males and females and for junior and senior high-school adolescents.Supported by National Institute of Child health and Human Development Grant HD 00376 and National Heart, Lung, and Blood Institute Grants HL 14230 (SCOR in Atherosclerosis) and HL R01 HL 20124.     

Effect of colchicine on experimental amyloidosis in two CBA/J mouse models. Chronic inflammatory stimulation and administration of amyloid-enhancing factor during acute inflammation

To investigate the mechanism of action of colchicine in blocking amyloid deposition, two model systems of amyloidosis in CBA/J mice were studied. In experimental chronic inflammation, daily injection of silver nitrate (AgNO3) resulted in the deposition of 667 +/- 68 ng of amyloid A protein (AA)/mg of spleen after 25 days. Treatment with 10 micrograms of colchicine daily decreased AgNO3-induced AA deposition to 12 +/- 1 ng of AA/mg of spleen (p less than 0.001). Colchicine diminished the acute phase serum amyloid A protein (SAA) response after 24 hours. Over a 25-day period, SAA concentrations declined and approached baseline both in colchicine-treated and (unexpectedly) in control mice. This suggested that suppression of SAA levels was not the primary event inhibiting amyloid deposition. In a model of accelerated amyloid deposition, injection of preformed amyloid-enhancing factor along with AgNO3 induced the deposition of 974 +/- 46 ng of AA/mg of spleen 48 hours later. Colchicine only partially decreased amyloid-enhancing factor-induced amyloid deposition to 578 +/- 91 ng of AA/mg of spleen, while blunting the acute phase SAA response. These results suggest that colchicine inhibits amyloidosis in the predeposition phase, possibly by blocking formation of amyloid-enhancing factor.     

Familial resemblance for glucose and insulin metabolism indices derived from an intravenous glucose tolerance test in Blacks and Whites of the HERITAGE Family Study

Type 2 diabetes mellitus (T2DM), characterized by hyperglycemia, is a complex disease primarily caused by impairment in insulin sensitivity (S_I) and insulin secretion. While a strong genetic component for T2DM is well established, there are few reports on racial differences in the magnitude of the genetic effects of T2DM and indices of glucose and insulin metabolism. We report here on the familial resemblance for traits related to glucose metabolism at pre-exercise training levels in 492 members from 99 sedentary White families and 259 members from 108 Black families participating in the multicenter HERITAGE Family Study. All these traits were obtained from the frequently sampled intravenous glucose tolerance test (IVGTT). They include glucose disappearance index (K_g), an overall index for glucose tolerance, acute insulin response to glucose (AIR_Glucose) which is an index for insulin secretion, and those derived from the minimal model including S_I and the disposition index (DI). DI, derived as the product of S_I and AIR_Glucose, is a measure of the activity of the B-cells adjusted for insulin resistance. After adjustment for age, sex, and body mass index, the maximal heritability estimates in Blacks (Whites) are 48±14% (25±8%) for K_g, 44±14% (46±8%) for AIR_Glucose, 38±12% (44±8%) for S_I and 32±14% (24±8%) for DI. Interestingly, Blacks have higher heritability for overall glucose tolerance than Whites but there is no race difference in heritability estimates for insulin sensitivity or insulin secretion.     

AIDS-related behavioral research and nursing

As efforts targeted at producing an effective vaccine or a definitive cure are still in early stages of development, health education and prevention continue to be this country's major line of defense against acquired immunodeficiency syndrome (AIDS). This defense is dependent on knowledge of behaviors that place individuals at risk of human immunodeficiency virus (HIV) exposure and disease progression. This article reviews the critical points in our state of knowledge and offers additional areas of need. Research is needed to determine a database of persons who use psychoactive substances and to understand the HIV-associated behaviors linked to drug use. Epidemiologic studies are necessary to appreciate the sexual, contraceptive, and childbearing practices of users of any psychoactive substance. Greater emphasis also is needed to investigate the inherent effects of various psychoactive substances on the immune, neurologic, and endocrine systems. While biomedical research continues, it is apparent that research from behavioral studies are crucial to education and prevention efforts. Nurse investigators are well-positioned to play an important role in accumulating this information. Given the critical role of drug abuse in the HIV epidemic, the public health significance cannot be overestimated.     

Vascular responses in canine subcutaneous adipose tissue to hypothalamic stimulation.

The present studies investigated vascular responses to electrical stimulation of the posterior hypothalamus in isolated but perfused and innervated subcutaneous adipose tissue in adult dogs. Three groups of dogs were distinguished: in one, electrical stimulation elicited vasodilation; in another, vasoconstriction, and in a third, neither significant vasodilation nor vasoconstriction occurred. Histological examination revealed that electrode placements were in the medial posterior hypothalamus, the lateral posterior hypothalamus, and the medial septal region, respectively. Hypothalamic stimulation failed to alter concentrations of free fatty acids or glycerol in venous blood from subcutaneous fat. Local beta-adrenergic block (propranolol) reversed the vasodilation to vasoconstriction while local alpha-adrenergic block (dihydroergotamine) abolished the vaso constrictor response. These results suggest that selective stimulation of the posterior hypothalamus results in neurogenic activation of both alpha- and beta-adrenergic mechanisms in adipose tissue vasculature. beta-Adrenergic vasodilation appears to predominate if the electrode is located medially, and alpha-adrenergic vasoconstriction appears to predominate if the electrode is located in the lateral posterior hypothalamus.