A glutamatergic mechanism for aluminum toxicity in astrocytes

The effect of aluminum on the metabolism of glutamate and glutamine in astrocytes was studied to provide information about a possible biochemical mechanism for aluminum neurotoxicity and its potential contribution to neurodegenerative disease. Exposure of cultured rat brain astrocytes for 3–4 d to 5–7.5 mM aluminum lactate increased glutamine synthetase activity by 100–300% and diminished glutaminase activity by 50–85%. Increased glutamine synthetase enzyme activity was accompanied by an elevated level of glutamine synthetase mRNA. Alterations in glutaminase and glutamine synthetase following aluminum exposure caused increased intracellular glutamine levels, decreased intracellular glutamate levels, and increased conversion of glutamate to glutamine and the release of the latter into the extracellular space. The results of these changes may alter the availability of neurotransmitter glutamate in vivo and may be a mechanism for the aluminum neurotoxicity observed in individuals exposed to the metal during dialysis procedures and other situations.     

Serving seniors better: service guidelines for supermarkets

Objective: Generate a list of service guidelines to enable supermarket managers to accommodate the needs of their older customers. Methods: Focus groups and a national telephone survey were conducted with Australian seniors to generate 10 service guidelines for supermarkets. Results: The 10 guidelines produced are considered to be of significant importance by Australian seniors, with some apparent differences in importance and relevance ratings between older and younger seniors, and males and females. Conclusions: Seniors have distinct service preferences when grocery shopping and their needs require special attention in the supermarket environment. In particular, they feel strongly about the quality of staff and equipment with which they come into contact.     

The AMPA receptor potentiator LY404187 increases cerebral glucose utilization and c-fos expression in the rat.

AMPA receptor potentiators enhance AMPA receptor-mediated glutamatergic neurotransmission and may have therapeutic potential as cognitive enhancers or antidepressants. The anatomical basis for the action of AMPA receptor potentiators is unknown. The aim of this study was to determine the effects of the biarylpropylsulfonamide AMPA receptor potentiator, LY404187 (0.05 to 5 mg/kg subcutaneously), upon cerebral glucose utilization and c-fos expression using 14C-2-deoxglucose autoradiography and c-fos immunocytochemistry. LY404187 (0.5 mg/kg) produced significant elevations in glucose utilization in 28 of the 52 anatomical regions analyzed, which included rostral neocortical areas and the hippocampus, as well the dorsal raphe nucleus, lateral habenula, and locus coeruleus. No significant decreases in glucose utilization were observed in any region after LY404187 administration. The increases in glucose utilization with LY404187 (0.5 mg/kg) were blocked by pretreatment with the AMPA receptor antagonist LY293558 (25 mg/kg), indicating that LY404187 acts through AMPA receptor-mediated mechanisms. LY404187 (0.5 mg/kg) also produced increases in c-fos immunoreactivity in the cortex, locus coeruleus, and the dorsal raphe nucleus. These studies demonstrate neuronal activation in key brain areas that are associated with memory processes and thus provide an anatomical basis for the cognitive enhancing effects of AMPA receptor potentiators.     

Start Talking About Risks: Development of a Motivational Interviewing-Based Safer Sex Program for People Living with HIV

The epidemiology of HIV infection in the US in general, and in the southeast, in particular, has shifted dramatically over the past two decades, increasingly affecting women and minorities. The site for our intervention was an infectious diseases clinic based at a university hospital serving over 1,300 HIV-infected patients in North Carolina. Our patient population is diverse and reflects the trends seen more broadly in the epidemic in the southeast and in North Carolina. Practicing safer sex is a complex behavior with multiple determinants that vary by individual and social context. A comprehensive intervention that is client-centered and can be tailored to each individual’s circumstances is more likely to be effective at reducing risky behaviors among clients such as ours than are more confrontational or standardized prevention messages. One potential approach to improving safer sex practices among people living with HIV/AIDS (PLWHA) is Motivational Interviewing (MI), a non-judgmental, client-centered but directive counseling style. Below, we describe: (1) the development of the Start Talking About Risks (STAR) MI-based safer sex counseling program for PLWHA at our clinic site; (2) the intervention itself; and (3) lessons learned from implementing the intervention.     

The effects of diet on inflammation: emphasis on the metabolic syndrome.

Reducing the incidence of coronary heart disease with diet is possible. The main dietary strategies include adequate omega-3 fatty acids intake, reduction of saturated and trans-fats, and consumption of a diet high in fruits, vegetables, nuts, and whole grains and low in refined grains. Each of these strategies may be associated with lower generation of inflammation. This review examines the epidemiologic and clinical evidence concerning diet and inflammation. Dietary patterns high in refined starches, sugar, and saturated and trans-fatty acids, poor in natural antioxidants and fiber from fruits, vegetables, and whole grains, and poor in omega-3 fatty acids may cause an activation of the innate immune system, most likely by an excessive production of proinflammatory cytokines associated with a reduced production of anti-inflammatory cytokines. The whole diet approach seems particularly promising to reduce the inflammation associated with the metabolic syndrome. The choice of healthy sources of carbohydrate, fat, and protein, associated with regular physical activity and avoidance of smoking, is critical to fighting the war against chronic disease. Western dietary patterns warm up inflammation, while prudent dietary patterns cool it down.     

Insulin, glucose, insulin resistance, and incident colorectal cancer in male smokers.

BACKGROUND & AIMS: Hyperinsulinemia is a putative colorectal cancer (CRC) risk factor. Insulin resistance (IR) commonly precedes hyperinsulinemia and can be quantitatively measured by using the homeostasis model assessment-insulin resistance (HOMA-IR) index. To date, few studies have directly examined serum insulin as an indicator of CRC risk, and none have reported associations on the basis of HOMA-IR. METHODS: We performed a case-cohort study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study (n=29,133). Baseline exposure and fasting serum biomarker data were available for 134 incident CRC case and 399 non-case subjects. HOMA-IR was derived as fasting insulin x fasting glucose/22.5. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by using age-adjusted and multivariable-adjusted Cox proportional hazards regression models. RESULTS: Median (interquartile range) values for serum insulin, glucose, and HOMA-IR were 4.1 (2.9-7.2) mIU/L, 101 (94-108) mg/dL, and 0.99 (0.69-1.98) for case subjects and 4.1 (2.7-6.1) mIU/L, 99 (93-107) mg/dL, and 1.02 (0.69-1.53) for non-case subjects, respectively. On the basis of comparison of the highest versus lowest quartiles for each biomarker, insulin (HR, 1.84; 95% CI, 1.03-3.30) and HOMA-IR (HR, 1.85; 95% CI, 1.06-3.24) were significantly associated with incident CRC, whereas glucose was marginally associated with incident CRC (HR, 1.70; 95% CI, 0.92-3.13) in age-adjusted risk models. However, trends across biomarker quartiles were somewhat inconsistent (P trend=.12, .04, and .12, respectively), and multivariable adjustment generally attenuated the observed risk estimates. CONCLUSIONS: Data from this prospective study of male smokers provide limited support for hyperinsulinemia, hyperglycemia, and/or insulin resistance as CRC risk factors.