Neurochemical mechanisms mediating the behavioral and cognitive effects of nicotine

Data are reviewed, largely from experiments in the authors'laboratory, that suggest three modes of action of systemic nicotine in producing three different types of effect upon behavior and cognitive function. (1) Preexposure of a stimulus without consequence makes it harder subsequently to form associations to that stimulus, a form of selective attention known as latent inhibition. Latent inhibition is blocked by nicotine, an effect that is apparently mediated by a nicotine-induced increase in dopamine release in the nucleus accumbens. (2) A single dose of nicotine proactively increases the partial reinforcement extinction effect measured several weeks later: that is, resistance to extinction is decreased by nicotine in animals that have been trained on a continuous reinforcement schedule, and increased in animals trained on a partial reinforcement schedule. This effect appears to be due to increased synthesis of tyrosine hydroxylase in the cell bodies of noradrenergic neurons in the locus coeruleus, followed by axonal transport to the hippocampus and increased synthesis and release of noradrenaline in that structure. (3) Nicotine improves vigilance in animals with cognitive deficits due to destruction of the forebrain cholinergic projection system, either as a consequence of excitotoxic lesions of the nuclei of origin of this system or after prolonged alcohol consumption; and also in human subjects with Alzheimer's disease (in which this system undergoes degeneration). This effect is most likely due to an action at denervated cholinergic synapses in the hippocampus and neocortex. © 1994 Wiley-Liss, Inc.     

Human embryonic stem cells: A potential source for cellular therapy

Many degenerative human diseases reflect damage to cells that are not normally repaired or replaced, such as diabetes, Parkinson's disease, hepatic failure and congestive heart failure. Preliminary studies in animals and humans have suggested that these diseases may be treatable by transplantation of healthy cells. Such cells may be obtained by in vitro culture of embryonic stem cells, which are capable of differentiating into many cell types. This review discusses applicative approaches for the derivation, maintenance and safety of human embryonic stem (hES) cells as well as ethical concerns surrounding their possible source for cellular therapy. hES cells offer broad application in cellular therapy; however, this review specifically emphasizes on cardiovascular repair, generation and characterization of hES cell-derived cardiomyocytes, vascular progenitors and differentiation of derivatives.     

Pycnogenol® as an Adjunct in the Management of Childhood Asthma

A randomized, placebo-controlled, double-blind study involving 60 subjects, aged 6-18 years old, was conducted over a period of 3 months to determine the effect of Pycnogenol® (a proprietary mixture of water-soluble bioflavonoids extracted from French maritime pine) on mild-to-moderate asthma. After baseline evaluation, subjects were randomized into two groups to receive either Pycnogenol® or placebo. Subjects were instructed to record their peak expiratory flow with an Assess® Peak Flow Meter each evening. At the same time, symptoms, daily use of rescue inhalers (albuterol), and any changes in oral medications were also recorded. Urine samples were obtained from the subjects at the end of the run-in period, and at 1-, 2-, and 3-month visits. Urinary leukotriene C₄/D₄/E₄ was measured by an enzyme immunoassay. Compared with subjects taking placebo, the group who took Pycnogenol® had significantly more improvement in pulmonary functions and asthma symptoms. The Pycnogenol® group was able to reduce or discontinue their use of rescue inhalers more often than the placebo group. There was also a significant reduction of urinary leukotrienes in the Pycnogenol® group. The results of this study demonstrate the efficacy of Pycnogenol® as an adjunct in the management of mild-to-moderate childhood asthma.     

Health literacy and contraception: a readability evaluation of contraceptive instructions for condoms, spermicides and emergency contraception in the USA.

OBJECTIVE: To assess readability of over-the-counter (OTC) contraceptive product instructions currently available, compare the results with previous studies from a decade ago, and review the implications for health care providers, in particular pharmacists counseling on OTC contraceptives. METHODS: A sample of contraceptive instructions was submitted to a readability analysis using four standard readability formulas. Products included condoms, spermicides, and emergency contraception instruction pamphlets. RESULTS: Reading grade levels for condoms ranged from 6th to 12th grade. The average reading levels for the spermicides were 9th-10th grade and for the emergency contraceptives 10th-12th grade. These results were consistent with those of similar studies performed a decade ago. CONCLUSIONS: Consumers need to have at least a high school reading level in order to comprehend current product instructions. Very little has changed in the past decade regarding readability of OTC contraceptive patient instructions, despite calls to simplify written instructions. Healthcare providers, in particular pharmacists, must be aware of these disparities to enhance patient education and advocate for simpler reading materials.     

Determinants of health-service use by low-income people.

Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies.