Elevated retinal zeaxanthin and prevention of light-induced photoreceptor cell death in quail

PURPOSE: Inferential evidence indicates that macular pigments (lutein and zeaxanthin) protect photoreceptors and/or retard age-related macular degeneration. These experiments tested the hypothesis that retinal zeaxanthin prevents light-induced photoreceptor cell death. METHODS: Retinal damage was assessed in quail fed a carotenoid-deficient (C-) diet for 6 months. Groups of 16 birds (8 male, 8 female) were fed a C- diet supplemented with 35 mg 3R,3'R-zeaxanthin for 1, 3, or 7 days; one group was continued on C- diets. Half of each group was exposed to intermittent 3200-lux white light (10 1-hour intervals separated by 2 hours in dark). After 14 additional hours in the dark, one retina of each quail was collected for HPLC analysis, and the contralateral retina was embedded in paraffin for counts of apoptotic nuclei. RESULTS: After 7 days' supplementation, concentrations of zeaxanthin in serum, liver, and fat had increased by factors of 50.8, 43.2, and 6.5, respectively (all P < 0.001). In contrast, retinal zeaxanthin fluctuated significantly upward on day 3, but there was no net change on day 7. The number of apoptotic rods and cones in light-damaged eyes correlated significantly and inversely with zeaxanthin concentration in the contralateral retina (r = -0.61; P < 0.0001 and r = -0.54; P < 0.002), but not with serum zeaxanthin. Similar correlations were observed with retinal lutein, which correlated strongly with retinal zeaxanthin (r = 0.95; P < 0.0001). CONCLUSIONS: Retinal zeaxanthin dose dependently reduced light-induced photoreceptor apoptosis; elevated serum levels did not. These data provide the first experimental evidence that xanthophyll carotenoids protect photoreceptors in vivo.     

Pharmaceutical Evaluation of Gas-Filled Microparticles as Gene Delivery System

Purpose. To produce and characterize a nonviral ultrasound-controlled release system of plasmid DNA (pDNA) encapsulated in gas-filled poly(D,L-lactide-co-glycolide) microparticles (PLGA-MPs). Methods. Different cationic polymers were used to form pDNA/polymer complexes to enhance the stability of pDNA during microparticle preparation. The physico-acoustical properties of the microparticles, particle size, pDNA integrity, encapsulation efficiency and pDNA release behavior were studied in vitro. Results. The microparticles had an average particle size of around 5 m. More than 50% of all microparticles contained a gas core, and when exposed to pulsed ultrasound as used for color Doppler imaging create a signal that yields typical color patterns (stimulated acoustic emission) as a result of the ultrasound-induced destruction of the microparticles. Thirty percent of the pDNA used was successfully encapsulated and approximately 10% of the encapsulated pDNA was released by ultrasound within 10 min. Conclusions. Plasmid DNA can be encapsulated in biodegradable gas-filled PLGA-MPs without hints for a structural disintegration. A pDNA release by ultrasound-induced microparticle-destruction could be shown in vitro.     

Hypovitaminosis D prevalence and determinants among African American and white women of reproductive age: third National Health and Nutrition Examination Survey, 1988-1994

BACKGROUND: Recent reports of rickets among African American children drew attention to the vitamin D status of these infants and their mothers. African American women are at higher risk of vitamin D deficiency than are white women, but few studies have examined determinants of hypovitaminosis D in this population. OBJECTIVE: We examined the prevalence and determinants of hypovitaminosis D among African American and white women of reproductive age. DESIGN: We examined 1546 African American women and 1426 white women aged 15-49 y who were not pregnant and who participated in the third National Health and Nutrition Examination Survey (1988-1994). Hypovitaminosis D was defined as a serum 25-hydroxyvitamin D concentration < or =37.5 nmol/L. Multiple logistic regression was used to examine the independent association of dietary, demographic, and behavioral determinants of hypovitaminosis D. RESULTS: The prevalence of hypovitaminosis D was 42.4 +/- 3.1% ( +/- SE) among African Americans and 4.2 +/- 0.7% among whites. Among African Americans, hypovitaminosis D was independently associated with consumption of milk or breakfast cereal <3 times/wk, no use of vitamin D supplements, season, urban residence, low body mass index, and no use of oral contraceptives. Even among 243 African Americans who consumed the adequate intake of vitamin D from supplements (200 IU/d), 28.2 +/- 2.7% had hypovitaminosis D. CONCLUSIONS: The high prevalence of hypovitaminosis D among African American women warrants further examination of vitamin D recommendations for these women. The determinants of hypovitaminosis D among women should be considered when these women are advised on dietary intake and supplement use.     

Nuclear translocation of endonuclease G and apoptosis-inducing factor during acetaminophen-induced liver cell injury.

Mitochondrial dysfunction and internucleosomal DNA fragmentation are well-recognized features of acetaminophen (AAP)-induced hepatocyte cell death. However, the endonucleases responsible for this effect have not been identified. Apoptosis-inducing factor (AIF) and endonuclease G are nucleases located in the intermembrane space of mitochondria. AIF is thought to trigger chromatin condensation and induce cleavage of DNA into high molecular weight fragments (50-300 kb), and endonuclease G can produce oligonucleosomal DNA fragments. Therefore, the objective of this investigation was to test the hypothesis that endonuclease G and AIF could be involved in AAP-induced nuclear DNA fragmentation. Using immunofluorescence microscopy, it was shown that in primary cultured mouse hepatocytes, endonuclease G and AIF translocated to the nucleus between 3 and 6 h after exposure to 5 mM AAP. In contrast, other mitochondrial intermembrane proteins such as cytochrome c or the second mitochondria-derived activator of caspases (Smac) did not accumulate in the nucleus. The translocation of AIF and endonuclease G correlated with mitochondrial dysfunction as indicated by the progressive loss of the mitochondrial membrane potential (measured with the JC-1 assay) and the appearance of nuclear DNA fragments in the cytosol (determined by an anti-histone ELISA). Pretreatment with 20mM N-acetylcysteine prevented mitochondrial dysfunction, the nuclear translocation of endonuclease G and AIF, and the nuclear DNA fragmentation. The data support the conclusion that endonuclease G and AIF translocate to the nucleus in response to AAP-induced mitochondrial dysfunction and may be responsible, at least in part, for the initial DNA fragmentation during AAP hepatotoxicity.     

Emergence of tics in children with attention deficit hyperactivity disorder treated with stimulant medications

The emergence of tics in children treated with stimulant medication for attention deficit hyperactivity disorder (ADHD) was investigated. A retrospective chart review of the medical records of 555 subjects was performed to examine the emergence of tics in relation to treatment with a stimulant medication, dosage, duration of treatment, and age of subjects. A total of 7.8% of the subjects treated with stimulants developed tics: 8.3% of subjects treated with methylphenidate, 6.3% with dextroamphetamine, and 7.7% with pemoline. The subjects who developed tics were significantly younger than those who did not. Subjects treated with higher doses of stimulant medication were not more likely to develop tics. While the emergence of tics was common, these subjects may have developed tics irrespective of stimulant medication. Controversy remains as to the long-term risk of tics in relation to stimulant medication and to appropriate practice should tics emerge during the course of stimulant medication treatment.     

Effects of feeding regimen on ethanol intake by guinea pigs

During daily two-hr sessions, guinea pigs licked a drinking tube filled with either 0 (tap water), 2, 4 or 8% (v/v) ethanol solution under three feeding regimens. Consumption of each solution was highest when sufficient food to maintain subjects at 90% of free-feeding weight was provided during sessions, lower when the same food ration was provided after sessions, and lowest when ad lib access to food was provided within and between sessions. However, this decrease in consumption across feeding regimens was inversely related to ethanol concentration. Under all feeding regimens, volume of solution consumed decreased with increasing ethanol concentration while milligrams ethanol consumed increased with ethanol concentration. These results are similar in some respects to previous findings with rats and monkeys, suggesting that further studies of oral ethanol self-administration by guinea pigs may be merited.     

Medicaid managed care for mental health services in a rural state

State governments throughout the country increasingly have turned to managed care for their Medicaid programs, including mental health services. We used ethnographic methods and a review of legal documents and state monitoring data to examine the impact of Medicaid reform on mental health services in New Mexico, a rural state. New Mexico implemented Medicaid managed care for both physical and mental health services in 1997. The reform led to administrative burdens, payment problems, and stress and high turnover among providers. Restrictions on inpatient and residential treatment exacerbated access problems for Medicaid recipients. These facts indicate that in rural, medically underserved states, the advantages of managed care for cost control, access, and quality assurance may be diminished. Responding to the crisis in mental health services, the federal government terminated New Mexico's program but later reversed its decision after political changes at the national level. This contradictory response suggests that the federal government's oversight role warrants careful scrutiny by advocacy groups at the local and state levels.     

Genetically engineered, live, attenuated vaccines protect nonhuman primates against aerosol challenge with a virulent IE strain of Venezuelan equine encephalitis virus

Two live, attenuated strains of Venezuelan equine encephalitis virus (VEE), IE1150K and V3526, were administered to macaques to determine if they could elicit protection against an aerosol challenge with virulent VEE virus of the IE variety (VEEV-IE). These viruses were rescued from full-length cDNA clones of 68U201 (VEEV-IE variety) and Trinidad donkey (VEEV-IA/B variety), respectively, and both have a furin cleavage site deletion mutation and a second-site resuscitating mutation. Both vaccines elicited neutralizing antibodies to viruses of the homologous variety but not to viruses of the heterologous variety. Eight weeks after vaccination, the macaques were challenged by aerosol exposure to virulent 68U201. Macaques vaccinated with V3526 were protected as well as macaques inoculated with IE1009, the wild-type infectious clone of 68U201. However, IE1150K failed to significantly protect macaques relative to controls. V3526 has now been shown to protect macaques against both IA/B [Pratt WD, Davis NL, Johnston RE, Smith JF. Genetically engineered, live attenuated vaccines for Venezuelan equine encephalitis: testing in animal models. Vaccine 2003;21(25-26):3854-62] and IE strains of VEE viruses.     

Drug effects on unconditioned light-avoidance in the rat

Rats avoid the brightly-illuminated arm of a Y-maze whose other arms are dark. This avoidance is unaffected by tranquillising drugs which reduce avoidance of an open sided, elevated arm, suggesting that these are two distinct behaviours which are probably under different motivational control.