Studies of aminochrome toxicity in a mouse derived neuronal cell line: is this toxicity mediated via glutamate transmission?

Summary. Aminochrome was found to be toxic in a mouse-derived neuronal cell line (CNh). The effect was concentration dependent (10–150 μM). The issue whether aminochrome toxicity involves glutamate transmission was studied with several glutamate receptors antagonists. Incubation of the cells with aminochrome (150 μM) in the presence of 100 μM of the AMPA an-tagonist, NBQX resulted in an increase of cell survival, from 52 to 73%. However, this protective effect did not seem to be related to activation of ionotropic glutamate receptors since incubation of CNh cells with 200 μM of glutamate resulted in only 10% decrease of cell survival. However, NBQX was found to inhibit in vitro the autoxidation process. One hundred μM AP-5 did not have any effect on aminochrome toxicity. The toxic effect of aminochrome on CNh cells seems to be dependent of extracellular activation since addition of dicoumarol, a specific inhibitor of DT-diaphorase, did not affect that toxicity, which can be explained perhaps by a lack of a transport system for aminochrome into the CNh cells. Received July 28, 1999, Accepted December 6, 1999     

Parvovirus-Derived Endogenous Viral Elements in Two South American Rodent Genomes

We describe endogenous viral elements (EVEs) derived from parvoviruses (family Parvoviridae) in the genomes of the long-tailed chinchilla (Chinchilla lanigera) and the degu (Octodon degus). The novel EVEs include dependovirus-related elements and representatives of a clearly distinct parvovirus lineage that also has endogenous representatives in marsupial genomes. In the degu, one dependovirus-derived EVE was found to carry an intact reading frame and was differentially expressed in vivo, with increased expression in the liver.     

Genetic diversity and population structure of a drought-tolerant species of <Emphasis Type="Italic">Eucalyptus</Emphasis>, using microsatellite markers

Given the impact of climate change on the availability of water resources, it becomes necessary the use of plant species well suited to planting on dryland sites. Eucalyptus cladocalyx, a native tree of South Australia, is capable of growing under relatively dry environments and saline soils. Two hundred twenty simple sequence repeat (microsatellites) markers, from a consensus linkage map of Eucalyptus, were selected to examine genetic diversity and population structure in a collection of E. cladocalyx introduced to southern Atacama Desert, Chile. A total of 130 microsatellites were successfully amplified, some of which are associated with quantitative traits of interest in Eucalyptus. Genetic analysis revealed a total of 457 alleles, ranging from 2 to 8 alleles per locus. A moderate level of genetic diversity (He = 0.492) and differentiation (FST = 0.086) was found among the populations. Mount Remarkable and Marble Range showed the highest and lowest level of genetic diversity, respectively. The Bayesian clustering analysis revealed three homogeneous genetic groups confirming that the individuals of E. cladocalyx from natural forest are highly and significantly structured. These results provide a novel information for the development of breeding strategies in E. cladocalyx by using marker-assisted selection in regions with low rainfall patterns.     

Temporal pattern of neuronal insulin release during Caenorhabditis elegans aging: Role of redox homeostasis

The insulin‐IGF‐1/DAF‐2 pathway has a central role in the determination of aging and longevity in Caenorhabditis elegans and other organisms. In this paper, we measured neuronal insulin secretion (using INS‐22::Venus) during C. elegans lifespan and monitored how this secretion is modified by redox homeostasis. We showed that INS‐22::Venus secretion fluctuates during the organism lifetime reaching maximum levels in the active reproductive stage. We also demonstrate that long‐lived daf‐2 insulin receptor mutants show remarkable low levels of INS‐22::Venus secretion. In contrast, we found that short‐lived mutant worms that lack the oxidation repair enzyme MSRA‐1 show increased levels of INS‐22::Venus secretion, specifically during the reproductive stage. MSRA‐1 is a target of the insulin‐IGF‐1/DAF‐2 pathway, and the expression of this antioxidant enzyme exclusively in the nervous system rescues the mutant insulin release phenotype and longevity. The msra‐1 mutant phenotype can also be reverted by antioxidant treatment during the active reproductive stage. We showed for the first time that there is a pattern of neuronal insulin release with a noticeable increment during the peak of reproduction. Our results suggest that redox homeostasis can modulate longevity through the regulation of insulin secretion, and that the insulin‐IGF‐1/DAF‐2 pathway could be regulated, at least in part, by a feedback loop. These findings highlight the importance of timing for therapeutic interventions aimed at improving health span.     

Relación entre el rendimiento en la prueba de estación unipodal y la velocidad del centro de presión en adultos mayores

Introduction

Frequent falls are one of the most important health problems in the elderly population. The unipedal stance test (UPST), asses postural stability and is used in fall risk measures. Despite this, there is little information about its relationship with posturographic parameters (PP) that characterizes postural stability. Center of pressure velocity (CoPV) is one of the best PP that describes postural stability. The aim of this study was to analyze the relation between UST score and CoPV in elderly population.

Materials and methods

A sample of 38 healthy elderly subjects where divided in two groups according to their UPST score, low performance (LP, n = 11) and high performance (HP, n = 27). The correlation between UPST score and COP mean velocity (CoPmV), recorded from a posturographic test, was analyzed between both groups.

Results

An inverse correlation between UPST score and CoPmV was found in both groups. However, this was higher in the LP group (r = −0.69, P = .02) compared to the HP (r = −0.39, P = .04).

Conclusions

Based on the results of this investigation, it may be concluded that the achievement on UPST has an inverse relationship with CoPmV, especially in subjects with low performance in the UPST.     

Oral elimination of strobila segments of Taenia saginata]

Within a 14-24 hours lapse after gynecological operative surgery, a 27-year-old woman eliminated with vomit two large taperworm pieces, measuring 3 and 2 meters respectively. At the laboratory they were identified as Taenia saginata strobila with immature, mature and gravid proglottids. The patient informed that she liked to eat raw beef. Treatment consisted in a single dose of praziquantel: 15 mg/kg body weight. Parasitological controls (two series of three fecal samples each), performed three months later, resulted negative for Taenia eggs.