Water-insoluble protein fractions increase in the brain cortical tissue and liver of rats during aging in both sexes. This suggests a possible increase in the cross-linking of proteins which may be due to the formation of, for example, hydroxyl free radicals during several metabolic processes. In vivo application of centrophenoxine causes a reversal of this phenomenon in old rats. In vitro experiments show that the generation of hydroxyl free radicals by chemical systems like homolysis of H2O2 by redox coupling with Fe2+ leads to Fe3+ conversion, results in the cross-linking of bovine serum albumin and the mixed proteins of liver or brain homogenates of young rats. The cross-linked proteins have a very much increased molecular weight, they become mostly insoluble even in 6 M urea. Dimethylaminoethanol, the effective part of the centrophenoxine molecules, is able to diminish the extent of cross-linking, acting most probably as a free-radical scavenger. The results are discussed in terms of the "membrane hypothesis of aging". A molecular basis is proposed for the anti-aging effect of centrophenoxine.

Aging↗

PubMedDate not supplied

Comments on review by G. E. Gibson and Ch. Peterson 'Calcium and the aging nervous system'.

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Aging↗

PubMedDate not supplied

A self-compartmentalizing protease in Rhodococcus: the 20S proteasome.

The 26S proteasome represents a major, energy-dependent and self-compartmentalizing protease system in eukaryotes. The proteolytic core of this complex, the 20S proteasome, is also ubiquitous in archaea. Although absent from most eubacteria, this multi-subunit protease was recently discovered in Rhodococcus and appears to be confined to actinomycetes. The eubacterial 20S proteasome represents an attractive complementary system to study proteasome assembly, quaternary structure, and catalytic mechanism. In addition, it is likely to contribute substantially to our understanding of the role of various self-compartmentalizing proteases in bacterial cells.

Adenosine Triphosphatases↗

PubMedDate not supplied

Applied aspects of Rhodococcus genetics.

Eubacteria of the genus Rhodococcus are a diverse group of microorganisms commonly found in many environmental niches from soils to seawaters and as plant and animal pathogens. They exhibit a remarkable ability to degrade many organic compounds and their economic importance is becoming increasingly apparent. Although their genetic organisation is still far from understood, there have been many advances in recent years. Reviewed here is the current knowledge of rhodococci relating to gene transfer, recombination, plasmid replication and functions, cloning vectors and reporter genes, gene expression and its control, bacteriophages, insertion sequences and genomic rearrangements. Further fundamental studies of Rhodococcus genetics and the application of genetic techniques to the these bacteria will be needed for their continued biotechnological exploitation.

Biotechnology↗

PubMedDate not supplied

Endocannabinoids and pain: spinal and peripheral analgesia in inflammation and neuropathy.

Analgesia is an important physiological function of the endocannabinoid system and one of significant clinical relevance. This review discusses the analgesic effects of endocannabinoids at spinal and peripheral levels, firstly by describing the physiological framework for analgesia and secondly by reviewing the evidence for analgesic effects of endocannabinoids obtained using animal models of clinical pain conditions. In the spinal cord, CB(1) receptors have been demonstrated in laminae of the dorsal horn intimately concerned with the processing of nociceptive information and the modulation thereof. Similarly, CB(1) receptors have been demonstrated on the cell bodies of primary afferent neurones; however, the exact phenotype of cells which express this receptor requires further elucidation. Local administration, peptide release and electrophysiological studies support the concept of spinally mediated endocannabinoid-induced analgesia. Whilst a proportion of the peripheral analgesic effect of endocannabinoids can be attributed to a neuronal mechanism acting through CB(1) receptors expressed by primary afferent neurones, the antiinflammatory actions of endocannabinoids, mediated through CB(2) receptors, also appears to contribute to local analgesic effects. Possible mechanisms of this CB(2)-mediated effect include the attenuation of NGF-induced mast cell degranulation and of neutrophil accumulation, both of which are processes known to contribute to the generation of inflammatory hyperalgesia. The analgesic effects of cannabinoids have been demonstrated in models of somatic and visceral inflammatory pain and of neuropathic pain, the latter being an important area of therapeutic need. Analgesia is one of the principal therapeutic targets of cannabinoids. This review will discuss the analgesic effects of endocannabinoids in relation to two areas of therapeutic need, persistent inflammation and neuropathic pain. The more general aspects of the role of cannabinoids, endogenous and exogenous, in analgesia have been recently reviewed elsewhere (Rice, Curr Opi Invest Drugs 2001; 2: 399-414; Pertwee, Prog Neurobil 2001; 63: 569-611; Rice, Mackie, In: Evers A. S, ed. Anesthetic Pharmacology: Physiologic Principles and Clinical Practice. St. Louis: Harcourt Health Sciences, 2002). Since a major goal in the development of cannabinoid-based analgesics is to divorce the antinociceptive effects from the psychotrophic effects, the discussion will focus on the antinociceptive effects produced at the spinal cord and/or peripheral level as these areas are the most attractive targets in this regard. A mechanistic discussion of the "framework" for analgesia will be followed by a description of studies examining the role of endocannabinoids in relieving pain; since the elucidation of these effects was undertaken using synthetic cannabinoids, reference will also be made to such studies, in the context of endocannabinoids.

Analgesia↗

PubMedDate not supplied

[The echographic diagnosis of intraocular tumors in children].

The echographic exam done on 14 children with leukocoria (white pupil) confirmed in 7 cases the retinoblastoma diagnosis. The exam differentiates the solid tumours from the cystic ones and points out the tumours with non-typical clinical aspect. Results from here the great importance of echography effectuation, especially in non-typical forms with difficult clinical diagnosis. The association of the echographic examination, together with the classical methods of investigation, contributes to the establishing of a correct diagnosis of the size and exact extension of the tumour.

Cataract↗