Cardiac autonomic regulation after lung exposure to carbon nanotubes.

The ultrafine (UF) component of airborne pollution may impair cardiovascular autonomic control, a high-risk condition for cardiovascular adverse events. Since engineered nanoparticles, such as single-walled carbon nanotubes (SWCNTs) share physicochemical properties with UF, they might have similar adverse effects. Aim of the study was to evaluate arterial baroreflex function (BRF) at baseline, 24 h after the first instillation, immediately before the second one, and 2 weeks later, in adult Wystar-Kyoto conscious rats undergoing two intratracheal instillations of SWCNT (eight rats) or phosphate buffer saline (PBS) (five rats) at 2-week interval. During each session, 30-min continuous recording of arterial pressure and pulse interval was performed by a telemetered catheter implanted in the abdominal aorta of the rats. BRF was studied by the sequence technique. SWCNTs dispersed in PBS (1 mg/ml) were administered immediately after sonication (1 microg/g body weight). A significant decrease in the number of baroreflex sequences (from 498 +/- 27.1 at baseline to 287 +/- 40.2 at the recording performed after 4 weeks; P < 0.05) was observed in SWCNT-instilled rats, whereas no significant change was detected in controls. These data suggest that SWCNTs may alter the BRF, thus affecting the autonomic cardiovascular control regulation.

A model of phenotypic susceptibility to tuberculosis: deficient in silico selection of Mycobacterium tuberculosis epitopes by HLA alleles.

HLA-DR allelic variants have been associated with tuberculosis (TB) susceptibility in different populations with risk ratios of 3.7 to 7.2. We hypothesized that the genetic susceptibility to TB depends upon the reduced capability of HLA-class II alleles of TB patients to bind and select peptide antigen from the Mycobacterium tuberculosis (MTB) expressed genome. To test this hypothesis, we developed a software that can predict HLA-DR restricted epitopes within the whole MTB genome based on quantitative peptide binding matrices. We analyzed the number of MTB epitopes recognized in two previously described populations of TB patients and matched controls and in a control population comprised of individuals affected by a sarcoid-like granuloma induced by beryllium and by healthy exposed controls. The number of putative epitopes within the whole MTB genome which could be bound by any HLA-DR allele (HLA-DR immunome of MTB) was 405,422 out of 1,304,277 possible 9-mers i.e., 31.08% of the global capability, instead of the expected 35%. When tested at an affinity level equivalent of the 1% of the best binder peptides, the HLA-DR alleles (HLA-DRB1*0801, *0802, *1401, *1501 and *1502) associated with TB susceptibility recognized a significantly lower mean number of MTB-epitopes (7,862 +/- 4,258) than the MTB-epitopes recognized by HLA-DR alleles (HLA-DRB1*0301, *0701, *1101, *1102, *1301 and *1302) negatively associated with TB (11,376 +/- 1,984, p<0.032). The number of epitopes bound at high affinity out of the whole MTB genome by the combination of the two HLA-DR alleles carried by each individual was lower in TB patients [TB-population 1: 11,341 +/- 908 (mean+SEM); TB-population 2: 15,303 +/- 657] than in matched healthy controls (CTR-population 1: 13,587 +/- 605, p<0.03 vs TB-population 1; CTR-population 2: 1,6841 +/- 555, p<0.04 vs TB-population 2). No difference was seen in individuals with the sarcoid-like granuloma induced by beryllium compared to the exposed healthy (beryllium-hypersensitivity: 17,593 +/- 447; controls 18,014 +/- 421; p=0.57). The data suggest that HLA-DR alleles associated with susceptibility to tuberculosis may be endowed with a reduced capability to bind at high affinity T-cell epitopes and select them for antigen presentation. The same alleles may contribute to determine the reaction to mycobacteria in non tuberculous granulomatous disorders.

M. avium binding to HLA-DR expressed alleles in silico: a model of phenotypic susceptibility to sarcoidosis.

Sarcoidosis is a systemic granulomatosis disease of unknown origin where a number of microbes, in particular M. tuberculosis and non-tuberculous mycobacteria, have been hypothesized to play a role in disease pathogenesis, possibly through bacterial antigen-driven hypersensitivity. To test this concept, we used bioinformatic tools allowing the identification of antigenic peptides in whole microbial genomes to analyze the interaction between the expressed HLA-DR gene allelic variants and the HLA-DR immunome of all pathogenic bacteria in a population of 149 sarcoidosis affected subjects and 447 controls, all HLA-typed at high resolution. We show here that patients with the Löfgren's syndrome, express HLA-DR alleles that recognize in silico a significantly higher number of bacterial antigen epitopes compared to the control population (18,496+9,114 vs 17,954+8,742; p<0.00001), and the chronic sarcoidosis affected population (17,954+8,742; p<0.00001 vs Löfgren's and controls). Further, the analysis of the ability of the HLA-DR allele combinations expressed by the Löfgren's and the chronic sarcoidosis affected subjects to recognize M. avium epitopes demonstrates that a significantly larger number of Löfgren's are capable of top affinity recognition, compared to chronic sarcoidosis (45% vs 17%, p<0.0037). Finally, both Löfgren's and chronic sarcoidosis subjects expressed HLA-DR allele combinations capable of M. tuberculosis and M. avium epitope recognition at higher affinity than tuberculosis affected subjects (p<0.01 all comparisons). In conclusion, we propose that - at least in a subgroup of affected subjects - sarcoidosis might be part of a spectrum of granulomatous responses to several agents where the Löfgren's syndrome represents the hyper-reactive end of the spectrum while pulmonary tuberculosis and atypical mycobacterial infections might represent the opposite end.

Neuroendocrine changes involved in the genesis of HD-induced orthostatic intolerance.

The aim of the present study was to analyze the role played by norepinephrine and epinephrine in Symptomatic (S) vs Non-Symptomatic (NS) subjects within a group of healthy volunteers undergoing a 4-hour-head-down bed rest study at -6 degrees.

A network of mitogen-activated protein kinases links G protein-coupled receptors to the c-jun promoter: a role for c-Jun NH2-terminal kinase, p38s, and extracellular signal-regulated kinase 5.

The expression of the c-jun proto-oncogene is rapidly induced in response to mitogens acting on a large variety of cell surface receptors. The resulting functional activity of c-Jun proteins appears to be critical for cell proliferation. Recently, we have shown that a large family of G protein-coupled receptors (GPCRs), represented by the m1 muscarinic receptor, can initiate intracellular signaling cascades that result in the activation of mitogen-activated protein kinases (MAPK) and c-Jun NH2-terminal kinases (JNK) and that the activation of JNK but not of MAPK correlated with a remarkable increase in the expression of c-jun mRNA. Subsequently, however, we obtained evidence that GPCRs can potently stimulate the activity of the c-jun promoter through MEF2 transcription factors, which do not act downstream from JNK. In view of these observations, we set out to investigate further the nature of the signaling pathway linking GPCRs to the c-jun promoter. Utilizing NIH 3T3 cells, we found that GPCRs can activate the c-jun promoter in a JNK-independent manner. Additionally, we demonstrated that these GPCRs can elevate the activity of novel members of the MAPK family, including ERK5, p38alpha, p38gamma, and p38delta, and that the activation of certain kinases acting downstream from MEK5 (ERK5) and MKK6 (p38alpha and p38gamma) is necessary to fully activate the c-jun promoter. Moreover, in addition to JNK, ERK5, p38alpha, and p38gamma were found to stimulate the c-jun promoter by acting on distinct responsive elements. Taken together, these results suggest that the pathway linking GPCRs to the c-jun promoter involves the integration of numerous signals transduced by a highly complex network of MAPK, rather than resulting from the stimulation of a single linear protein kinase cascade. Furthermore, our findings suggest that each signaling pathway affects one or more regulatory elements on the c-jun promoter and that the transcriptional response most likely results from the temporal integration of each of these biochemical routes.

[Intraoperative calibration of the Vater's papilla using Fogarty's biliary catheter]. / Calibratura intraoperatoria della papilla di Vater mediante catetere biliare di Fogarty.

The study included 20 patients affected by cholelithiasis and choledocholithiasis. Al patients underwent cholecystectomy; after choledochotomy, choledochal stones were removed using a Fogarty's biliary catheter (no. 5) and, subsequently, the papilla was calibrated by inserting the end balloon of the catheter, which and been filled with 0.3 cc of water, beyond the level of the papilla itself. The catheter was then withdrawn. No T-tubes were left in the common bile duct in any patient, no post-operative complications were observed and all patients were dismissed within seven days.