Loss of T-type Calcium Current in Sensory Neurons of Rats with Neuropathic Pain

Background: Pathophysiology in the primary sensory neuron may contribute to chronic neuropathic pain. Ca channels play a central role in neuronal processes, and sensory neurons are rich in low-voltage-activated calcium channels (LVACCs). However, the physiologic function of these channels is unknown. Their possible role in rebound burst firing makes them a candidate for increased excitability after neuropathic injury.

Methods: This study uses pharmacological methods to isolate LVACC in cells from the dorsal root ganglia of neuropathic and sham-operated rats, including the blockade of high-voltage-activated Ca channels with fluoride and selective toxins. LVACCs were examined with conventional whole cell patch clamp electrophysiology techniques.

Results: After chronic constriction injury of the peripheral axon, LVACC was significantly reduced compared to sham rats as shown by a 60% reduction in peak current density and an 80% reduction in total calcium influx. A depolarizing shift in the voltage dependence of activation and an increase in the rate of deactivation and inactivation appear to cause this reduction of LVACC. Either Ni2+ or mibefradil, blockers of LVACC, applied in the bath to normal dorsal root ganglion cells during current clamp significantly and reversibly increased excitability.     

Effect of Policosanol on Foam-cell Formation in Carrageenan-induced Granulomas in Rats

Policosanol is a new cholesterol-lowering drug isolated and purified from sugar-cane wax. which prevents the development of lipofundin-induced lesions and foam-cell formation in New Zealand rabbits and Wistar rats. This study was conducted to examine the effects of policosanol on foam-cell formation in carrageenan-induced granulomas in rats. Eighteen Wistar rats were randomly distributed in three experimental groups which received orally for 20 days Tween 20 H₂O as vehicle (control group) or policosanol at 2.5 or 25 mg kg^?1. At the 11th day. lipofundin was injected intrapcritoneally for 8 days to induce formation of foam cells in the granuloma. At day 13, carrageenan was injected subcutaneously for granuloma induction and seven days later animals were killed. A significant reduction of the foam-cell formation in granulomas of policosanol-treated rats was observed. It is concluded that policosanol prevents the development of foam cells in carrageenan-induced granulomas (extravascular medium) in rats.     

Ultrastructure of another spiral organism associated with human gastritis

Summary Campylobacter pylori may not be the only organism that causes active chronic gastritis in man. We report two cases of gastric infection with a spiral organism distinct fromC. pylori. The first patient is a 36-year-old female who presented with epigastric pain and abdominal colic present since childhood and who had 14 cats. Endoscopy was normal. The second patient kept two dogs. Histology of gastric mucosal biopsy specimens in both patients revealed active chronic gastritis, most severe in body mucosa. Giemsa stain revealed bacteria with four to eight spirals, 0.5 m in diameter and 3–7 m in length. The organisms had multiple sheathed flagella at the pole and smooth cell walls without axial filaments. The organisms resembled the gastric spirillum that has been seen in cats, dogs, and nonhuman primates. After antibacterial therapy with bismuth subsalicylate, amoxicillin, and metronidazole, the organisms disappeared in both patients and the gastritis healed.UnlikeC. pylori, this new spirillum prefers to colonize gastric mucosa containing parietal cells. Whereas this type of organism is a common commensal in other mammals, it appears to be associated with and a possible cause of gastritis in humans.     

HLA and Kaposi''s sarcoma in Sardinia

Twelve Sardinian patients affected by histologically defined classic Kaposi's sarcoma (KS) were HLA-A, B, C and DR typed. Compared to 220 age and ethnically matched healthy controls, KS patients showed a significant increase in HLA-DR5 (66.6 vs 23.1%, P less than 0.001) and a considerable decrease in HLA-DR3 (8.3 vs 53.6%, P = 0.0055). No definite association was observed for other HLA antigens. These results confirm the existence of an HLA associated genetic control of KS susceptibility and support the hypothesis that HLA-DR5 plays the role of a predisposition marker while HLA-DR3 bears a genetic resistance to the disease.     

Histopathology of mixed anaerobic intraabdominal infection in mice

Summary This study characterized acute peritonitis and chronic abscess formation resulting from experimental mixed anaerobic infection withBacteroides melaninogenicus andFusobacterium necrophorum. At intervals after infection liver and spleen samples were obtained, fixed, and processed for histological examination. An acute to chronic infection progressed in mice infected with this mixture of anaerobic bacteria, whereas, no infection resulted when either organism was injected alone. Acute inflammatory cell infiltrates were noted in tissue samples at 12 h postinfection. Small, discrete areas of liver cell necrosis with neutrophilic infiltrates were observed as early as 24 h. By 48 h after infection the liver parenchyma was infiltrated with both acute and chronic inflammatory cells, with moderate to severe hepatocyte degeneration recognized at 72 h. Large intrahepatic abscesses were present in the subphrenic (upper lobe) area 2 to 6 weeks after experimental infection.     

Enhancement of Bacteroides intermedius growth by Fusobacterium necrophorum.

Previous work from this laboratory has demonstrated the persistence of Bacteroides intermedius in the livers of mice receiving an intraperitoneal inoculum of B. intermedius and Fusobacterium necrophorum. This study was undertaken to determine whether F. necrophorum enhanced the in vitro growth of B. intermedius. Tryptose phosphate broth did not support the growth of B. intermedius alone, but the bacterium did survive in a tryptose phosphate broth culture of F. necrophorum. B. intermedius cultured in F. necrophorum-conditioned tryptose phosphate broth grew impressively, reaching maximal absorbance at 24 h after inoculation. The growth of B. intermedius in F. necrophorum-conditioned tryptose phosphate broth was proportional to the amount of conditioned medium present. The B. intermedius growth-stimulating factor was detectable in conditioned medium 8 h after inoculation with F. necrophorum and could be detected throughout the 96-h incubation period. Growth-factor-active fractions eluted from a Sephadex G-100 column did not absorb at 280 nm and were retained on the column until 4 column volumes were eluted. The growth factor was nondialyzable and stable to boiling, lyophilization, extraction with hot aqueous phenol, and trypsin digestion. The factor was inactivated by exposure to pH 2.0 in the pepsin digestion protocol. Significant amounts of hexose, methyl pentose, and 2-keto-3-deoxyoctonate were detected in pooled growth-factor-active fractions eluted from the Sephadex column. This pool was also active in the Limulus lysate endotoxin assay. These results suggest that the B. intermedius growth-stimulating factor produced by F. necrophorum is a lipopolysaccharide.     

A high-molecular-weight fraction of smooth lipopolysaccharide in Klebsiella serotype O1:K20 contains a unique O-antigen epitope and determines resistance to nonspecific serum killing

The lipopolysaccharide (LPS) O-antigen side chains of Klebsiella serotype O1 have been studied by using mutants selected by resistance to a Klebsiella bacteriophage designated O1-A. Two classes of LPS mutants were identified. The major group (90%) synthesized rough LPS. The remaining 10% of the mutants produced a novel LPS profile that lacked the highest-molecular-weight O-substituted molecules (HMW-LPS) but still produced lower-molecular-weight O-substituted species (LMW-LPS). By using antisera raised against mutant Klebsiella strains and antiserum specific for Pasteurella haemolytica serotype 4, it was demonstrated that HMW-LPS and LMW-LPS contain shared epitopes. HMW-LPS also contained an epitope absent in LMW-LPS. This unique epitope was recognized by a monoclonal antibody (O1-52.6) and appears to be responsible for the serological cross-reaction between the O antigens of Klebsiella O1 and Escherichia coli O19. This HMW-LPS epitope was present in eight other Klebsiella O1 isolates which were examined. Electron microscopy demonstrated that HMW-LPS excluded overlying capsular polysaccharide for a distance of 25 to 40 nm. The distance was reduced to 10 to 18 nm in strains which synthesized only LMW-LPS and to zero in rough LPS strains. The HMW-LPS of Klebsiella O1 was shown to be an important virulence determinant, since this molecule was responsible for the resistance of the bacterium to nonspecific, complement-mediated serum killing.     

SKALP/elafin gene polymorphisms are not associated with pustular forms of psoriasis

Psoriasis is a multifactorial skin disease characterised by epidermal abnormalities and infiltration by lymphocytes and polymorphonuclear leukocytes (PMN). Skin-derived antileukoproteinase (SKALP), also known as elafin, is a potent inhibitor of human leukocyte elastase and proteinase 3, two PMN-derived proteinases implicated in tissue destruction and leukocyte migration. We have shown that, at least at the protein level, SKALP is significantly decreased in lesional skin of patients with pustular psoriasis compared with plaque-type psoriasis. This finding raised the possibility that SKALP could be one of the candidate genes for pustular forms of psoriasis. We therefore performed single strand conformation polymorphism (SSCP) analysis on the SKALP gene to screen for mutations/polymorphisms in the exons of 30 patients with plaque-type psoriasis, 15 patients with pustular psoriasis and 48 healthy controls. In exon 1 a polymorphism was detected at position + 43 relative to the translation start site, resulting in a substitution of threonine for alanine in the signal peptide. In the promoter region a dinucleotide repeat polymorphism was identified. Both polymorphisms were not associated with pustular psoriasis, or psoriasis in general. Our data indicate that the decrease in SKALP activity in pustular psoriasis is not caused by mutations in the coding region of the gene, and that there is no allelic association between pustular psoriasis and SKALP gene polymorphisms.     

Functional Analysis of B-L (Ia-Like) Antigen-Bearing Chicken Peripheral Blood Cells

The functional of B-L (Ia-equivalent)-positive (B-L+) adn -negative (B-L-) chicken peripheral blood lymphocytes (PBL) was studied in vitro and in vivo. The PBL were first stained in direct immunofluorescence tests with a fluorescein isothiocyanate-labelled anti-B-L alloantiserum and then separated by means of a fluorescence-activated cell sorter. In agreement with our previous findings, B-L- cells showed functional properties of T lymphocytes, responding to concanavalin A and phytohaemagglutinin-P in vitro and inducing a graft-versus-host (GVH) reaction when injected into allogeneic embryos. Sorted B-L+ gave no responses in any of these assays. Neither B-L+ nor B-L- cells, when tested alone, responded significantly to pokeweed mitogen, but mixtures of the two restored the responsiveness to that of the original unsorted suspension. Of the B-L+ PBL, 10% were T cells, which may account for the low GVH reactivity given by this population.     

bcl-2 transgene expression promotes survival and reduces proliferation of CD3-CD4-CD8- T cell progenitors

Proliferative expansion and apoptotic cell death play prominent roles in T cell development. The molecular control of cell cycle progression and apoptosis appear to be inter-connected since the Bcl-2 protein can inhibit apoptosis and slow cell cycle progression in cortical thymocytes and mature T cells, particularly during the transition from the quiescent state into the cell cycle. Here the impact of bcl-2 transgene expression on CD3-CD4-CD8- T cell progenitors was assessed. Bcl-2 enhanced the survival of these progenitors at all of the four major differentiation stages, CD25- CD44+ (pro-T1), CD25 + CD44+ (pro- T2), CD25 + CD44- (pro-T3) and CD25-CD44- (pro-T4). However, it reduced cell cycling and slowed turnover only in the pro-T4 subset. From an analysis of bcl-2 transgenic mice expressing a TCR transgene or bearing a mutation in the scid or rag-1 gene we conclude that Bcl-2 inhibits proliferation only of T cell progenitors that are activated via the pre- TCR, not those stimulated via c-Kit and the IL-7 receptor.