Search

The thermodynamic behavior of mixed monolayers of cardiolipin-dipalmitoylphosphatidylcholine (CLP-DPPC) and cardiolipin-dipalmitoylphosphatidylethanolamine (CLP-DPPE) is investigated by studying their Langmuir surface pressure and surface potential isotherms at different cardiolipin molar fractions. The overall thermodynamic behavior is independent of mole fraction for the mixed CLP-DPPC monolayers while a critical fraction exists for the CLP-DPPE monolayers.

Three phospholipase-like myotoxins, Bothrops asper myotoxin II, Agkistrodon piscivorus piscivorus K49 and Vipera ammodytes ammodytin L, can bind to long-chain fatty acids in a spontaneous autocatalytic reaction without the presence of calcium ions as cofactors. A phospholipase A2, with lysine or serine at position 49 in the active site instead of the expected aspartate residue, is found in several snake venoms. Membrane leakage is caused by these myotoxins through a unique cytolitic mechanism despite their lack of catalytic activity or calcium binding.These myotoxins are the first protein group that undergo acylation spontaneously with free fatty acids.

Rufini, S., P. De Vito, N. Balestro, M. Pescatori, P. Luly, and S. Incerpi. PLA2 stimulation of [Na.sup.+]/[H.sub.+] antiport and proliferation in rat aortic smooth muscle cells. Am. J. Physiol. 277 (Cell Physiol. 46): C814-C822, 1999.--The proliferative properties and the ability to stimulate the [Na.sup.+]/[H.sup.+] antiport activity of a secretory phospholipase [A.sub.2] were studied in rat aortic smooth muscle cells in culture: The requirement of the enzymatic activity of phospholipase [A.sub.2] to elicit mitogenesis was assessed by the use of ammodytin L, a [Ser.sub.49] phospholipase [A.sub.2] from the venom of Vipera ammodytes, devoid of hydrolytic activity. We propose that the proliferative effect is mediated by the same transduction pathway for both proteins. In particular, 1) both secretory phospholipase [A.sub.2] and ammodytin L stimulated thymidine incorporation in a dose-dependent manner; 2) both proteins affected the cell cycle, as assessed by cell growth and fluorescence-activated cell sorting experiments; 3) both phospholipase [A.sub.2] and ammodytin L increased intracellular pH, a permissive factor for cell proliferation, through activation of the [Na.sup.+]/[H.sup.+] antiport; 4) ammodytin L was able to displace the [sup.125]I-labeled phospholipase [A.sub.2] from specific binding sites in a concentration range consistent with that capable of eliciting a cellular response; and 5) the inhibition by heparin was similar for both proteins, taking into account the ratio of heparin to protein. In conclusion, the enzymatic activity of phospholipase [A.sub.2] is not required for the stimulation of mitogenesis. The inhibitory effect of heparin combined with its therapeutic potential could help to clarify the role of phospholipase [A.sub.2] in the pathogenesis of several preinflammatory situations. phospholipases [A.sub.2]; snake venom; ammodytin L; [Na.sup.+]/[H.sup.+] antiport; growth factors; heparin

Recently, a study has shown that a polymorphism in the region of MIR1279 modulates the expression of the TRAF3IP2 gene. Since polymorphisms in the TRAF3IP2 gene have been described in association with systemic lupus erithematosus (SLE) susceptibility and with the development of pericarditis, our aim is to verify if the MIR1279 gene variability could also be involved. The rs1463335 SNP, located upstream MIR1279 gene, was analyzed by allelic discrimination assay in 315 Italian SLE patients and 201 healthy controls. Moreover, the MIR1279 gene was full sequenced in 50 patients. A case/control association study and a genotype/phenotype correlation analysis were performed. We also constructed a pericarditis genetic risk profile for patients with SLE. The full sequencing of the MIR1279 gene in patients with SLE did not reveal any novel or known variation. The variant allele of the rs1463335 SNP was significantly associated with susceptibility to pericarditis (P = 0.017 and OR = 1.67). A risk profile model for pericarditis considering the risk alleles of MIR1279 and three other genes (STAT4, PTPN2 and TRAF3IP2) showed that patients with 4 or 5 risk alleles have a higher risk of developing pericarditis (OR = 4.09 with P = 0.001 and OR = 6.04 with P = 0.04 respectively). In conclusion, we describe for the first time the contribution of a MIR1279 SNP in pericarditis development in patients with SLE and a genetic risk profile model that could be useful to identify patients more susceptible to developing pericarditis in SLE. This approach could help to improve the prediction and the management of this complication. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a systemic autoimmune disease resulting in chronic inflammation of the synovium and consequent cartilage and bone erosion. RA is associated strongly with the presence of rheumatoid factor (RF), and consists of clinical subsets of anti-citrullinated protein antibody (ACPA)-positive and -negative patients. This study was designed to evaluate whether relevant single nucleotide polymorphisms (SNPs) associated with RA and other autoimmune disorders are related to RF, ACPA and clinical phenotype in a cohort of biologic drugs naive Italian RA patients; 192 RA patients and 278 age-matched healthy controls were included. Clinical and laboratory data were registered. We analysed a total of 12 single nucleotide polymorphisms (SNPs) in signal transducer and activator of transcription-4 (STAT-4), interleukin (IL)-10, psoriasis susceptibility 1 candidate 1 (PSORS1C1), protein tyrosine phosphatase, non-receptor type 2 (PTPN2), endoplasmic reticulum aminopeptidase 1 (ERAP1), tumour necrosis factor receptor-associated 3 interacting protein 2 (TRAF3IP2) and microRNA 146a (MIR146A) genes by allelic discrimination assays. Case-control association studies and genotype/phenotype correlation analyses were performed. A higher risk to develop RA was observed for rs7574865 in the STAT-4 gene, while the rs1800872 in the IL-10 gene showed a protective effect. The presence of RF was associated significantly with rs1800872 variant in IL-10, while rs2910164 in MIR146A was protective. ACPA were associated significantly with rs7574865 in STAT-4. The SNP rs2233945 in the PSORS1C1 gene was protective regarding the presence of bone erosions, while rs2542151 in PTPN2 gene was associated with joint damage. Our results confirm that polymorphisms in STAT-4 and IL-10 genes confer susceptibility to RA. For the first time, we described that SNPs in PSORS1C1, PTPN2 and MIR146A genes were associated differently with a severe disease phenotype in terms of autoantibody status and radiographic damage in an Italian RA population. [ABSTRACT FROM AUTHOR]

Niemann-Pick type C disease is an autosomal recessive storage disorder, characterized by abnormal sequestration of unesterified cholesterol within the late endolysosomal compartment of cells and accumulation of gangliosides and other sphingolipids. Progressive neurological deterioration and insurgence of symptoms like ataxia, seizure, and cognitive decline until severe dementia are pathognomonic features of the disease. Here, we studied synaptic plasticity phenomena and evaluated ERKs activation in the hippocampus of BALB/c NPC1−/− mice, a well described animal model of the disease. Our results demonstrated an impairment of both induction and maintenance of long term synaptic potentiation in NPC1−/− mouse slices, associated with the lack of ERKs phosphorylation. We then investigated the effects of Miglustat, a recent approved drug for the treatment of NPCD. We found that in vivo Miglustat administration in NPC1−/− mice was able to rescue synaptic plasticity deficits, to restore ERKs activation and to counteract hyperexcitability. Overall, these data indicate that Miglustat may be effective for treating the neurological deficits associated with NPCD, such as seizures and dementia. [ABSTRACT FROM AUTHOR]

We studied the effects of ion cyclotron resonance (Seqex) magnetic therapy on the blood of thirty two healthy volunteers. They received 15 treatments each 27 minutes in length, distributed over 5 weeks. The concentrations of two blood components, malondialdehyde (MDA) and cholesterol were measured in each subject, immediately before and immediately after the 15 treatments as well as one month after the final treatment. Highly significant reductions in MDA concentrations, averaging 53.8% were noted just after the 15 treatments, tending to return to the original concentrations one month later. The effect on HDL and LDL cholesterol levels were not significant. The implication of this work is that this type of therapy may be useful in dealing with oxidative stress. [ABSTRACT FROM AUTHOR]

The current knowledge assigns a crucial role to the Rho GTPases family (Rho, Rac, Cdc42) in the complex transductive pathway leading to skeletal muscle cell differentiation. Their exact function in myogenesis, however, remains largely undefined. The protein toxin CNF1 was herein employed as a tool to activate Rho, Rac and Cdc42 in the myogenic cell line C2C12. We demonstrated that CNF1 impaired myogenesis by affecting the muscle regulatory factors MyoD and myogenin and the structural protein MHC expressions. This was principally driven by Rac/Cdc42 activation whereas Rho apparently controlled only the fusion process. More importantly, we proved that a controlled balance between Rho and Rac/Cdc42 activation/deactivation state was crucial for the correct execution of the differentiation program, thus providing a novel view for the role of Rho GTPases in muscle cell differentiation. Also, the use of Rho hijacking toxins can represent a new strategy to pharmacologically influence the differentiative process.Cell Death and Differentiation (2005) 12, 78-86. doi:10.1038/sj.cdd.4401522 Published online 29 October 2004 [ABSTRACT FROM AUTHOR]

Lysosomes play an important role in the immune system functioning and are involved in different aspects of inflammatory reaction, repair processes and tissue damage at various levels. Among various effects, it is known that physical exercise influences the release of different lysosomal components. The aim of this study was to evaluate enzyme activity and isoenzymatic profile of βN-acetylhexosaminidase both in kidney and urine of normal and trained rats. Enzyme activity was measured by fluorimetric assay while β-N-acetylhexosaminidase isoenzymes were separated using DEAE-cellulose chromatography. Hexosaminidase specific activity was significantly increased in urine of trained rats whereas there was no increase in the kidneys of trained rats. Indeed, no significant differences were observed in the isoenzyme profile of kidney and urine extracts from normal and trained rats. Our findings suggest the exerciseinduced release of lysosomal enzymes is a functional effect and not due to disruption of lysosomal membranes. [ABSTRACT FROM AUTHOR]

Zinc is involved in the biochemical processes supporting life, such as cellular respiration, DNA reproduction, maintenance of cell membrane integrity and free radical scavenging. Zinc is required for the activity of more than 300 enzymes, covering all 6 classes of enzyme activity. Zinc binding sites in proteins are often of distorted tetrahedral or trigonal bipyramidal geometry, made up of the sulphur of cysteine, the nitrogen of histidine or the oxygen of aspartate and glutamate, or a combination. Zinc in proteins can either participate directly in chemical catalysis or be important for maintaining protein structure and stability. The nutritional habits of elite athletes during training and competition are quite different from the recommended diet in the majority of the population. Endurance athletes often adopt an unusual diet in an attempt to enhance performance: an excessive increase in carbohydrates and low intake of proteins and fat may lead to suboptimal zinc intake in 90% of athletes. Mild zinc deficiency is difficult to detect because of the lack of definitive indicators of zinc status. In athletes, zinc deficiency can lead to anorexia, significant loss in bodyweight, latent fatigue with decreased endurance and a risk of osteoporosis. [ABSTRACT FROM AUTHOR]

The chemical composition of liver plasma membrane was studied in Wistar rats aged between 3 and 24 months. Results obtained indicate a significant age-dependent positive correlation of both the protein:phospholipid and cholesterol:phospholipid ratios, whereas the protein:cholesterol ratio seems to remain unaffected. Phospholipid analysis of liver plasma membrane reveals that only the phosphatidylcholine content has a significant negative correlation with age; all other phospholipid species remain basically unchanged. [ABSTRACT FROM AUTHOR]

Six species of Cratoxylum are found in Thailand. Whether the Cratoxylum formosum ssp. pruniflorum (CFP) has anticancer properties requires investigation. CFP exhibited cytotoxicity against hepatocellular carcinoma HepG2 cells. Based on FTIR microspectroscopy, CFP raised the respective lipid and nucleic acid content and β-pleated sheet in HepG2 cells, suggesting a change in the secondary protein structure. CFP induced apoptosis by increasing the activities of various caspases. Overexpression of TRAILR2 indicated the extrinsic pathway while expression of Bax/Bcl-2 ratio indicated the intrinsic pathway and decreased expression of Bid indicated cross-talk between the two. CFP alkylated the DNA and caused DNA damage, which may be the initial step in the intrinsic pathway. CFP indirectly and directly inhibited Top IB enzyme activity and decreased PARP—the protein-related DNA repair process. CFP could, thus, protect the resistance mechanism of cancer by reversing the effect of Top as confirmed by apoptosis induction in the resistant HepG2 cells. The phytochemical analysis suggested that the compounds playing an important role in the anticancer activity of CFP are a group of xanthones. [ABSTRACT FROM AUTHOR]