Distinct genomic copy number in mitochondria of different mammalian organs

This study shows that mitochondria in liver, kidney, heart, and brain of the mouse have a distinct mitochondrial density. It also demonstrates that the mtDNA copy number per mitochondrion is organ-specific. A reliable method of determining mitochondrial density per organ is by stereological analysis of tissue sections while mtDNA quantitation is by the use of radiolabelled mtDNA probe. This is the first study in which a comprehensive examination of mitochondrial density and quantitation of mitochondrial genomes in mouse organs have been done. In summary the variability is not only in mitochondrial density but also in genomic copy number in mitochondria of various tissues.     

Developmental analysis of the cell recognition mechanism in the ciliate Euplotes raikovi

Euplotes raikovi, like other ciliates, passes through a postconjugal immaturity, operatively identified by an apparent cell inability to form mating pairs under experimental conditions that are the same as those used for inducing mating at maturity. In cells homozygous for the gene mat-2, which controls the pheromone Er-2, Er-2 mRNA synthesis and mature Er-2 secretion were shown to start from the very beginning of the life cycle and continue throughout immaturity, although to extents estimated to be 5- to 10-fold lower than at maturity. In addition, experiments of ¹²⁵ I-Er-2 binding and crosslinking provided evidence that autocrine pheromone-binding sites, showing values of the dissociation constant of the order of 10^?9 M, are on the surface of immature cells. The number of these sites per cell was estimated to increase from less than 10⁶ per cell of 5–7 fissions of age, to about 16 × 10⁶ at maturity. These results were taken to suggest that a pheromone-receptor production is stimulated during immaturity by autocrine pheromone binding to cells and that this production might be essential for the development of a pheromone-receptor density high enough to transform the cell from “immature” to “adult,” that is competent to respond as well to pheromones of conspecific, genetically different cells. © 1992 Wiley-Liss, Inc.     

Global asymptotic stability for a vector disease model with spatial spread

Summary We analyze the global behaviour of a vector disease model which involves spatial spread and hereditary effects. This model can be applied to investigate growth and spread of malaria. No immunization is considered. We prove that, if the recovery rate is less than or equal to a threshold value, the disease dies out, otherwise the infectious people density tends to a homogeneous distribution. Our results follow using contracting convexes techniques and agree with the results given by K. L. Cooke for the model without diffusion.Work supported by C.N.R., Grant No. 79.00696.01.     

The effects of ecolabels on environmentally- and health-friendly cars: an online survey and two experimental studies

The International Journal of Life Cycle Assessment - Given the increasing importance of political decision-making to reduce emission targets, the main purpose of the current paper is to identify...     

Glucose Accelerates Copper- and Ceruloplasmin-induced Oxidation of Low-density Lipoprotein and Whole Serum

Glucose at pathophysiological concentrations was able to accelerate copper-induced oxidation of isolated low-density lipoprotein (LDL) and whole serum. The efficiency of glucose was favored under the following circumstances: (a) when LDL oxidation was induced by low copper concentration, (b) when LDL was partly oxidized, i.e. enriched with lipid peroxides. The glucose derivative methyl- &#102 - d -glucoside was ineffective on Cu 2+ -induced LDL oxidation, pointing out the essential role of the reactivity of the aldehydic carbon for the pro-oxidative effect. When LDL oxidation was induced by a peroxyl radical generator, as a model of transition metal independent oxidation, glucose was ineffective. Glucose was found to stimulate oxidation of LDL induced by ceruloplasmin, the major copper-containing protein of human plasma. Thus, glucose accelerated oxidation of LDL induced by both free and protein bound copper. Considering the requirement for catalytically active copper and for the aldehydic carbon, the pro-oxidative effect of glucose is likely to depend on the increased availability of Cu + ; this is more efficient in decomposing lipid peroxide than Cu 2+ , accounting for acceleration of LDL oxidation. The possible biological relevance of our work is supported by the finding that glucose was able to accelerate oxidation of whole serum, which was assessed by monitoring low-level chemiluminescence associated with lipid peroxidation.     

Different Permeability of Potassium Salts across the Blood-Brain Barrier Follows the Hofmeister Series

The passage of ions across biological membranes is regulated by passive and active mechanisms. Passive ion diffusion into organs depends on the ion-pairing properties of salts present in the serum. Potassium ions could affect brain activity by crossing the blood-brain barrier (BBB) and its accumulation in the extracellular cerebral space could precipitate seizures. In the present study, we analyze passive diffusion of a series of potassium salts in the in vitro isolated guinea pig brain preparation. Different potassium counter-anions confer ion-pairing and lipophilicity properties that modulate membrane diffusion of the salt. Extracellular recordings in different cortical areas demonstrated the presence of epileptiform activities that strongly relate to anion identity, following the qualitative order of the Hofmeister series. Indeed, highly lipophilic salts that easily cross the BBB enhanced extracellular potassium concentration measured by ion-selective electrodes and were the most effective pro-epileptic species. This study constitutes a novel contribution for the understanding of the potential epileptogenicity of potassium salts and, more generally, of the role of counter-anions in the passive passage of salts through biological membranes.     

Phylogeographical pattern of Euplotes nobilii,a protist ciliate with a bipolar biogeographical distribution

Nuclear (18S and ITS) and mitochondrial (16S) ribosomal RNA gene sequences were determined from genetically distinct wild‐type strains of Antarctic (nine strains), Fuegian (four strains), Greenland (nine strains) and Svalbard (three strains) populations of the marine ciliate, Euplotes nobilii, and analysed for their nucleotide polymorphisms. A close genetic homogeneity was found within and between the Antarctic and Fuegian populations, while more significant levels of genetic differentiation were detected within and between the two Arctic populations, as well as between these populations and the Antarctic/Fuegian ones. The phylogeographical pattern that was derived from these data indicates that gene flow is not limited among Arctic populations; it equally connects the Arctic and Antarctic populations either directly, or through the Fuegian population. This indication reinforces previous evidence from laboratory assays of mating interactions between some of the strains analysed in this work that Southern and Northern polar populations of E. nobilii belong to a unique, panmictic population that substantially share the same gene pool.     

A meta-analysis of randomized controlled trials comparing endoscopic and open carpal tunnel decompression

Controversy exists regarding the benefit of endoscopic carpal tunnel release versus open carpal tunnel release in terms of grip/pinch strength, scar tenderness, pain, return to work, reversible/irreversible nerve damage, and adverse effects. Although a number of randomized controlled trials and systematic reviews have been published on the subject, to date, no large definitive randomized controlled trial or meta-analysis has been performed comparing endoscopic to open carpal tunnel release. This meta-analysis was undertaken to address the effectiveness of endoscopic carpal tunnel release relative to open carpal tunnel release. Key outcome measures from 13 randomized controlled trials were extracted and statistically combined. Heterogeneity was observed in three of the outcomes (i.e., grip strength, pain, and return to work), but the causes of heterogeneity could not be explained because of insufficient detail in the reported studies. Using the Jadad et al. scale, nine of 13 studies were of low methodologic quality. The effect sizes were compared between the studies that were rated as high quality and the studies that were rated as low quality on the Jadad et al. scale. Similarly, the studies that were rated as high quality on the Gerritsen et al. scale were compared with those that were rated as low quality. No clinically significant difference in effect sizes was apparent between studies of high and low methodologic quality. This meta-analysis supports the conclusion that endoscopic carpal tunnel release is favored over the open carpal tunnel release in terms of a reduction in scar tenderness and increase in grip and pinch strength at a 12-week follow-up. With regard to symptom relief and return to work, the data are inconclusive. Irreversible nerve damage is uncommon in either technique; however, there is an increased susceptibility to reversible nerve injury that is three times as likely to occur with endoscopic carpal tunnel release than with open carpal tunnel release.     

Decompression of the common peroneal nerve: experience with 20 consecutive cases

A retrospective review of 20 patients with common peroneal nerve palsy treated with decompression between 1986 and 1997 was undertaken. Subjects were evaluated preoperatively and postoperatively by electromyography, nerve conduction, and clinical measures. The mean interval between the onset of symptoms to surgery (operative delay) was 15.9 months. The mean postoperative follow-up was 32.2 months with a minimum follow-up of 1 year. Decompression was performed at the level of the fibular neck and slightly distally at the tendinous origin of the peroneus longus using a standard approach to release tight fascial structures or scar tissue. External neurolysis was performed using the operating microscope in two cases for which scarring of the nerve was identified intraoperatively. Postoperatively, 19 of 20 patients showed improvement in ankle dorsiflexion as assessed by the Medical Research Council scale. Electromyographic examination was useful in the preoperative evaluation and selection of patients for decompression surgery. In conclusion, decompression even after a 1-year delay may offer benefit and suggest early intervention in patients with a severe lesion.