Nitric oxide-induced release of acetylcholine in the nucleus accumbens: role of cyclic GMP, glutamate, and GABA

We have previously shown that the basal acetylcholine release in the ventral striatum is under the enhancing influence of endogenous nitric oxide (NO) and that NO donors cause pronounced increases in the acetylcholine release rate. To investigate the role of cyclic GMP, glutamate, and GABA in the NO-induced acetylcholine release, we superfused the nucleus accumbens, (Nac) of the anesthetized rat with various compounds through a push-pull cannula and determined the neurotransmitter released in the perfusate. Superfusion of the Nac with the NO donors diethylamine/NO (DEANO; 100 micromol/L), S-nitroso-N-acetylpenicillamine (SNAP; 200 micromol/L), or 3-morpholinosydnonimine (SIN-1; 200 micromol/L) enhanced the acetylcholine release rate. The guanylyl cyclase inhibitor 1H-(1,2,4)-oxodiazolo(4,3-a)quinoxalin-1-one (ODQ; 10 micromol/L) abolished the effects of DEANO and SIN-1. 6-(Phenylamino)-5,8-quinolinedione (LY-83583; 100 micromol/L), which also inhibits cyclic GMP synthesis, inhibited the releasing effects of DEANO and of SNAP, whereas the effect of SIN-1 on acetylcholine release was not influenced. The DEANO-induced release of acetylcholine was also abolished in the presence of 20 micromol/L 6,6-dinitroquinoxaline-2,3-dione (DNQX) and 10 micromol/L (+/-)-2-amino-5-phosphonopentanoic acid (AP-5). Simultaneous superfusion with 50 micromol/L quinpirole and 10 micromol/L 7-bromo-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SKF 83566) was ineffective. Superfusion with 500 micromol/L DEANO decreased the release of acetylcholine. The inhibitory effect of 500 micromol/L DEANO was reversed to an enhanced release on superfusion with 20 micromol/L bicuculline. Bicuculline also enhanced the basal release rate. These findings indicate that cyclic GMP mediates the NO-induced release of acetylcholine by enhancing the outflow of glutamate. Dopamine is not involved in this process. Only high concentrations of NO increase the output of GABA, which in turn decreases acetylcholine release. Our results suggest that cells that are able to release glutamate, such as glutamatergic neurons, are the main target of NO in the Nac.     

Effect of storage and heating on phytosterol concentrations in vegetable oils determined by GC/MS

Phytosterols can be of value in decreasing cardiovascular risk of coronary heart disease. β‐Sitosterol was the most abundant sterol in the three oils studied (sunflower, olive and ‘4 oil mixture’). The total phytosterol level was the highest in the ‘4 oil mixture’ compared with the other oils studied. Tests performed on the effect of aging (heating at 50 °C for several weeks and at 100 °C for 1 h) did not show any significant variation in the phytosterol content. In contrast, heating at 200 °C for 1 h led to a 50–60% decrease of phytosterol in the oils studied and in the standard solutions. Copyright © 2005 Society of Chemical Industry     

Effects of Food Storage and Handling on Blow Fly (Lucilia sericata) Eggs and Larvae

ABSTRACT: Flies can cause food-borne disease by transmitting pathogenic microorganisms into the food we eat or by being ingested themselves ("intestinal myiasis"), usually as eggs or larvae contaminating our food. Because eggs and larvae can easily contaminate our food during harvesting, handling, and preparation, this series of experiments was undertaken to define the food preparation conditions that would be necessary to kill contaminating blow fly eggs and larvae. Replicate samples of Lucilia (= Phaenicia) sericata (Meigen) eggs and larvae were exposed to increasing periods of freezing, refrigeration, baking, boiling, frying, and microwaving. Survivors were counted every 6 to 48 h thereafter, and the exposures that were lethal to 50% (LE₅₀), 90% (LE₉₀), and 99% of our samples (LE₉₉) were calculated. All of the tested food-preparation methods killed most or all of the eggs and larvae when exposed for durations typically associated with food preparation. These results indicate that the common methods of food preparation should adequately kill all L. sericata eggs and larvae that may be associated with raw meat. Freezing and extended refrigeration also killed all eggs and larvae. This supports the belief, hitherto unproven, that contamination of cooked meat products most likely occurs at or after the point of retail-consumer contact.     

Podiatric medical resources on the Internet

PURPOSE: To determine utility of polymerase chain reaction (PCR)-based urine screening for Chlamydia trachomatis in the care of adolescent females in an urban clinic. METHODS: Females > or = 15 years of age attending an adolescent clinic were approached consecutively. Each enrollee was interviewed to determine the primary reason(s) for the clinic visit and was queried about genitourinary symptoms. Nonsterile voided urine specimens were tested for C. trachomatis using PCR-based analysis. Endocervical C. trachomatis cultures were obtained from the subjects who had a pelvic examination. Main outcome measures were chlamydia infection rates in clinic attendees whether a pelvic examination was performed or not. RESULTS: A total of 315 (99.4%) of 317 patients approached agreed to participate. Overall, 47 (14.9%) patients had positive urine PCR tests. The chlamydia infection rate detected by urine PCR was 22.1% (19 of 86) among those who had pelvic examinations performed and 12.2% (28 of 229) among those who did not (p = .03; odds ratio 2.04; 95% confidence interval 1.02, 4.06). Sixty percent (28 of 47) of chlamydia infections identified during the study period were identified by the urine screening test. CONCLUSION: Urine screening was accepted by vast majority of female adolescents attending the clinic irrespective of reason for the clinic visit, and was highly effective in identifying unsuspected C. trachomatis infections, particularly among girls attending the clinic for reasons unrelated to reproductive health care and as an interim screening tool for adolescent family-planning clients.     

Longitudinal working models: Estimates of household energy consumption in Australia

The paper uses household expenditure survey data and alternative functional specifications of Engel's laws to establish an empirical pattern of disaggregate energy (ie electricity, gas, other fuels and gasoline) demand characterized by different demographic attributes for use in a combined panel data model of energy consumption and impact in Australia. The findings lend support, in terms of statistical efficiency and economic–theoretic plausibility, to the dominance of the Working form over the conventional linear Allen–Bowley function. Energy as a whole is a necessity while at the disaggregate level gasoline is considered a luxury. The findings indicate in this respect the existence of demand elasticity bias in aggregate energy models.     

Efficient Groebner walk conversion for implicitization of geometric objects

In this paper, the author uses recent theoretical results from the method of Groebner bases to improve the efficiency of algorithms for implicitization. The method of Groebner bases has some important advantages, namely it is reliable and it can solve the implicitization problem in full generality.

The main result of this paper is that we can significantly improve the efficiency of implicitization algorithms using the deterministic Groebner walk conversion while maintaining the reliability of the algorithms. More precisely, the calculation of the implicit equations will be partitioned into several smaller computations following a path in the Groebner fan of the ideal generated by the system of equations. This method works with ideals of zero-dimension as well as positive dimension. The author uses a deterministic method to vary the weight vectors in order to ensure that the computation involves polynomials with just a few terms. A new concept of ideal-specified term orders for elimination is introduced to further improve the efficiency. As the result, the improved algorithms overcome the bottle-neck of the traditional implicitization algorithms by avoiding unnecessary zero-reductions and coefficient swell. Furthermore, the improved algorithms are able to avoid many unnecessary walking steps during the calculation of the implicit equations.

Several test-suites such as the Newell's teapot are used to test the new approach. The average performance is many times faster than traditional Groebner basis based algorithms for implicitization.