Effects of an Intraparenchymal Injection of Lidocaine in the Rat Cervical Spinal Cord

Lidocaine effects in the spinal cord have been extensively investigated over the years. Although the intrathecal route is usually used to treat insults occurring in the spinal cord, the local delivery drug via intraparenchymal infusions has gained increasing favor for the treatment of some neurodegenerative disorders. The aim of the present study was to evaluate the behavioral and tissue effects of the intraparenchymal injection of different concentrations of lidocaine into the rat cervical spinal cord. Young male Sprague–Dawley rats were intraparenchymally injected with 0.5%, 1% or 2% lidocaine at the C5 segment of the spinal cord. Other rats were injected with saline solution (sham group). Hot plate test was determined at 0, 1, 2, 3, 7 and 14 post-injection (pi) days. Rats of each experimental group were euthanized either at 1, 2, 3, 7 or 14 pi days. Intact animals were used as controls. Sections of the C5 segment were used for histological, immunohistochemical or immunofluorescence analysis. Injection of 0.5% lidocaine did not affect neuronal counting, did not evoke an inflammatory reaction, nor induce astrocyte activation. Therefore, a concentration of 0.5% lidocaine is suggested to promote anti-inflammatory effects after injury.     

Microbial biomass product from apple pomace in batch and fed batch cultures

Summary Apple pomace, a solid waste from ap-ple processing industries, was used as the raw ma-terial for production of a protein enriched pro-duct. The experiments were conducted on a small scale in Erlenmeyer flasks or 4-1 fermentors in batch and fed-batch processes usingSaccharo-mycopsis lipolytica and Trichoderma reesei in sin-gle and mixed cultures. The results obtained indi-cate the technical feasibility of the process for ob-taining products containing 13% to 15% protein, on dry basis, which is adequate for cattle feed-ing.     

Metabolic activity of phagocytes in experimental sporotrichosis

Phagocytosis plays an important role as a protective mechanism against infections, since polymorphonuclear leukocytes (PMN) and macrophages are the first cellular lines opposed to agressive microorganisms. In patients with sporotrichosis a diminished capability of killing engulfed yeast by their PMN has been described, but the origin of this deficiency remains unknown.In this work, partial aspects of the oxidative metabolism of PMN leukocytes and peritoneal macrophages of mongolian gerbils experimentally infected with sporotrichosis were studied. For this purpose the nitroblue tetrazolium (NBT) test as described by Baehner and Nathan (1) and myeloperoxidase activity measured according to Kaplow's method were utilized.The PMN and macrophages of mongolian gerbils infected with sporotrichosis showed increased reduction of NBT when compared with the phagocytic cells of normal ones, as is usually observed in most infections. Myeloperoxidase activity was diminished in both PMN and macrophages, but this diminution was statistically significant only in PMN leukocytes. These results show that part of the oxidative mechanisms of phagocytic cells can be impaired in experimental sporotrichosis, and could be correlated with the diminished fungicidal activity of PMN leukocytes obtained from patients infected with sporotrichosis.     

Interactions among phospholipids of guinea pig rough microsomes,effect of fat deficiency

Summary The fatty acid composition and the steady-state fluorescence anisotropy (r_s) of 1,6-diphenyl-1,3,5-hexatriene (DPH) were determined for each of the five major phospholipid (PL) classes present in the liver rough microsomes (RM) of guinea pigs fed with control and fat-deprived diets. In order to obtain information about PL-PL interactions and their contribution to the overall membrane fluidity the experimental r_s of phospholipid mixtures were compared to the molar weighed average values of the individual phospholipid r_s values. The PL ratios in the mixtures were the same to those found in the RM membranes. Binary mixtures of phosphatidylcholine (PC) with phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and sphingomyelin (SM) show higher values of r_s than those estimated from the individual component parameters indicating a rigidizing interaction. The rigidizing effect of PE was also observed when this phospholipid was sonicated with mixtures of PC with PS and PI. However, no rigidizing effect of PE was observed in the PC bilayers when SM was included in the composition suggesting that PE-SM interactions prevent rigidizing effects of PE. Besides, in spite that PC-PI and PC-PS mixtures have rigidizing interactions, the incorporation of PI and PS to PC-PS and PC-PI mixtures, respectively, have a fluidizing effect. In consequence, phospholipid polar head groups interact in RM membranes modifying the molecular packing and/or the rotational diffusion of acyl chains. The complexity and variety of constituent phospholipids could prevent major changes in the fluidity. The comparison of results obtained with PL mixtures of control and fat-deficient animals indicate that a change in the number of double bonds does not evoke a significant difference between either the rigidizing of fluidizing effects. However, there is a general tendency indicating that phospholipids with higher double bond index evoke lower rigidizing and fluidizing interactions. Moreover, PL of animals fed a fat-deficient diet have less fluidity than those of control animals.Member of the Carrera del Investigador Científico, Consejo Nacional de Investìgaciones Científicas y Técnicas, Argentina.     

Effect of nutritional factors on the culture of Nostoc sp. as a source of phycobiliproteins

Summary The effect of nutritional factors in a new culture medium (BW₃) is described for the cyanobacterium Nostoc sp. The growth of Nostoc sp. was higher in BW₃ than in control media currently used for cyanobacteria. With medium BW₃ the content of the pigment c-phycocyanin depended on the culture conditions employed, particularly the nature of the nitrogen and carbon sources. Higher amounts of c-phycocyanin amounting to 20.1% on a dry-weight basis were accumulated when both sources were supplied in the gas phase of the culture. The phycobiliproteins of Nostoc sp. were resolved into two components: c-phycocyanin (_max = 614 nm) and allophycocyanin (_max = 652 nm). The phycobiliprotein composition was 30% allophycocyanin and 70% c-phycocyanin. The culture of Nostoc sp. in BW₃ medium seems promising as a source of biomass for the production of natural dyes.     

Micro-determination of amino acid composition of proteins electroblotted onto polyvinylidene difluoride membranes

A method for determination of amino acid composition of proteins separated by SDS-polyacrylamide gel electrophoresis and transferred to polyvinylidene difluoride (PVDF) membranes is described. A single blotted band containing 50 to 200 pmoles of protein was cut out and submitted to acid hydrolysis with HCl followed by derivatization with phenylisothiocyanate. The amino acid derivatives were separated by reverse phase high-performance liquid chromatography. Bovine serum albumin, lysozyme, myoglobin, ovalbumin, soybean trypsin inhibitor and carbonic anhydrase were analyzed; the results revealed a good correspondence with reported values. This can be considered an analytical method to determine the amino acid composition of samples from microquantities of protein mixtures, particularly in those cases in which SDS-polyacrylamide gel electrophoresis is the most suitable separation system.     

Biosynthesis of cyclic β-(1–3),β-(1–6) glucan in Bradyrhizobium spp.

Inner membranes of Bradyrhizobium japonicum strain USDA 110 produced in vitro soluble and insoluble -(1–3),-(1–6) glucans. The reaction proceeded through a 90 kDa inner membrane intermediate protein; used UDP-glucose as sugar donor and required Mg²⁺. Gel chromatography of soluble glucans resolved a cyclic -(1–3) glucan with a degree of polymerization of eleven from a family of -(1–3),-(1–6) glucans with variable degree of polymerization higher than eleven. Bradyrhizobium strains BR4406 and BR8404 isolated from tree legume nodules in Southeast Brazil produce -(1–3),-(1–6) glucans very similar to that of B. japonicum. A 100 kDa protein was identified in these strains as intermediates in the synthesis of these glucans. Inner membranes of B. japonicum USDA110, B. japonicum I17, and Bradyrhizobium strains BR4406 and BR8404 incubated with UDP-glucose were unable to synthesize -(1–2) glucan and lacked the 235 kDa intermediate protein known to be involved in the synthesis of -(1–2) glucan in Agrobacterium tumefaciens, Rhizobium meliloti and Rhizobium loti.Abbreviations EPS= exopolysaccharides - CPS= capsular polysaccharides - LPS= lipopolysaccharides - AMA= Yeast extract-mannitol medium - TY= tryptone-yeast extract - PMSF= phenyl methyl sulfonil fluoride

---

     

The ultimate carcinogen of 4-nitroquinoline 1-oxide does not react with Z-DNA and hyperreacts with B-Z junctions.

DNA secondary and tertiary structures are known to affect the reaction between the double helix and several damaging agents. We have previously shown that the tertiary structure of DNA influences the reactivity of 4-acetoxyaminoquinoline 1-oxide (Ac-4-HAQO), the ultimate carcinogen of 4-nitroquinoline 1-oxide (4-NQO), being more reactive with naturally supercoiled DNA than with relaxed DNA. The relative proportion of the three main stable adducts and of an unstable adduct, that resulted in strand scission and/or AP sites, was also affected by the degree of supercoiling of plasmid DNA. In this study we examined the influence of Z-DNA structure on the reactivity of Ac-4-HAQO by mapping the distribution of the two main Ac-4-HAQO adducts, C8-guanine and N2-guanine, along a (dC-dG)16 sequence inserted at the BamHI site of pBR322 plasmid DNA. This insert adopted the left-handed Z and right-handed B structure depending on the superhelical density of the plasmid. Sites of C8-guanine adduct formation were determined by hot piperidine cleavage of Ac-4-HAQO modified DNA, while N2-guanine adducts were mapped by the arrest of the 3'-5' exonuclease activity of T4 DNA polymerase. The results showed that Ac-4-HAQO did not react with guanine residues when the (dC-dG)16 sequence was in Z conformation, while hyperreactivity at the B-Z junction was observed. These results indicate that Ac-4-HAQO can probe the polymorphism of DNA at the nucleotide level.