Non-life-threatening sepsis: report of two cases

Streptococcus bovis is one of the nonenterococcal species included among the streptococci group D. It is part of the normal bowel flora in humans and animals, but it is also responsible for infectious diseases (10-15% of all cases of bacterial endocarditis). Many cases of bacteremia and metastatic abscesses (spleen, liver, soft tissues, bone, meninges, endocardium) caused by S. bovis were reported as associated with digestive tract diseases, mainly colonic disease, and, in particular colonic neoplasms, or chronic liver diseases. A role in carcinogenesis has been suggested for this microorganism. The authors report two cases of S. bovis sepsis, one associated with colonic neoplasm and the other with liver cirrhosis and gastric carcinoma. Discussion is focused on probable mechanisms that favor gastric colonization and systemic diffusion of S. bovis from the gut in patients with gastrointestinal neoplasms or chronic liver disease and provides clinical recommendations for patients with S. bovis infections.     

Evaluation of contrast‐enhanced digital mammography (CEDM) in the preoperative staging of breast cancer: Large‐scale single‐center experience

One of the most important indications for contrast‐enhanced breast imaging is the presurgical breast cancer (BC) staging. This is a large‐scale single‐center experience which evaluates the role of CEDM in presurgical staging and its impact on surgical planning. The aims of this retrospective study were to define the diagnostic performance of CEDM in the presurgical setting and to identify which types of patients could benefit from having CEDM. We selected 326 patients with BC who underwent CEDM as preoperative staging and had breast cancer‐related surgery at our institution. We analyzed those cases in which CEDM led to additional imaging or biopsy and those in which it changed the type of surgery that was planned according to conventional breast imaging (CI) techniques (digital mammography, tomosynthesis and bilateral handheld ultrasound). CEDM sensitivity in identifying the index lesion and sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, and accuracy in the correct preoperative staging of BC of the whole population and in various subgroups were calculated. CEDM sensitivity for the index lesion was 98.8% (322/326), which led to additional breast imaging in 23.6% (77/326) of patients and additional biopsies in 17.5% (57/326). CEDM changed the type of surgery in 18.4% (60/326). In the preoperative breast cancer staging, CEDM sensitivity, specificity, PPV, NPV, and accuracy produced results of 93%, 98%, 90%, 98%, and 97%, respectively. CEDM performance was better in patients with palpable lesions. CEDM has an excellent diagnostic performance in the presurgical staging of BC. Symptomatic patients with palpable lesions benefitted most from preoperative CEDM, with a statistically significant difference compared with nonpalpable.     

CRAT missense variants cause abnormal carnitine acetyltransferase function in an early‐onset case of Leigh syndrome

Leigh syndrome, or subacute necrotizing encephalomyelopathy, is one of the most severe pediatric disorders of the mitochondrial energy metabolism. By performing whole‐exome sequencing in a girl affected by Leigh syndrome and her parents, we identified two heterozygous missense variants (p.Tyr110Cys and p.Val569Met) in the carnitine acetyltransferase (CRAT) gene, encoding an enzyme involved in the control of mitochondrial short‐chain acyl‐CoA concentrations. Biochemical assays revealed carnitine acetyltransferase deficiency in the proband‐derived fibroblasts. Functional analyses of recombinant‐purified CRAT proteins demonstrated that both missense variants, located in the acyl‐group binding site of the enzyme, severely impair its catalytic function toward acetyl‐CoA, and the p.Val569Met variant also toward propionyl‐CoA and octanoyl‐CoA. Although a single recessive variant in CRAT has been recently associated with neurodegeneration with brain iron accumulation (NBIA), this study reports the first kinetic analysis of naturally occurring CRAT variants and demonstrates the genetic basis of carnitine acetyltransferase deficiency in a case of mitochondrial encephalopathy.     

[N‐Methyl‐11C]choline by on‐column reaction: a study on [11C]CH3I incorporation and the residual amount of precursor in the product

[N‐Methyl‐¹¹C]choline has been synthesized at room temperature by the reaction of [¹¹C]CH₃I with 2‐dimethylaminoethanol (DMAE), with the latter directly loaded on a weak cation‐exchange cartridge. Most of the efforts have been directed to reduce the amount of residual precursor in the product's final solution in order to make this tracer more suitable to brain studies. In the process, radiochemical yields and residual DMAE have been placed in relation with both the starting amount of precursor and the rinsing conditions used and compared with the more ‘traditional’ loading of the precursor on either a C18 cartridge or a loop. Comments and indications on the most convenient analytical technique and conditions for quantitative analysis, with particular emphasis on the precursor, are also reported. Under what we believe to be a fair compromise, [¹¹C]CH₃I incorporation yields of ca. 90% were easily achieved with a residual amount of starting material in the 8‐ to 12‐ppm range. Copyright © 2010 John Wiley & Sons, Ltd.     

Functional topography of the secondary somatosensory cortex for nonpainful and painful stimulation of median and tibial nerve: an fMRI study

Functional magnetic resonance imaging (fMRI) was used to study the cortical activity of the bilateral secondary somatosensory cortex (SII) during nonpainful (motor threshold) and painful electrical stimulation of median and tibial nerves. fMRI recordings were performed in eight normal young adults. The aim was at evaluating the working hypothesis of a spatial segregation of nonpainful and painful populations not only in the "hand" representation of SII [Ferretti, A., Babiloni, C., Del Gratta, C., Caulo, M., Tartaro, A., Bonomo, L., Rossini, P.M., Romani, G.L., 2003. Functional topography of the secondary somatosensory cortex for nonpainful and painful stimuli: an fMRI study. NeuroImage 20, 1625-1638.] but also in its "foot" representation. Results showed that, in both "hand" and "foot" representations of bilateral SII, the activity elicited by the painful stimulation was localized more posteriorly with respect to that elicited by the nonpainful stimulation. A fine spatial analysis of the SII responses revealed a clear somatotopic organization in the bilateral SII subregion especially reactive to the nonpainful stimuli (i.e., segregation of the hand and foot representations). In contrast, it was not possible to disentangle the "hand" and "foot" representations of SII for painful stimuli. These results extended to the SII "foot" representation previous evidence of a spatial segregation in the SII "hand" representation of subregions for the painful and nonpainful stimuli. Furthermore, they suggest that noxious information is not somatotopically represented in human bilateral SII, at least as inferred from fMRI data at 1.5 T.     

Tubed Flap Interpolation in Reconstruction of Helical and Ear Lobe Defects

Background. A useful reconstructive tool, as a delayed method, for marginal defects of the ear of more than 2.5 cm wide with no deficit of the cartilaginous frame and low scapha involvement, consists of tubed flaps raised from neighboring areas. The patients treated with this technique sustained a dog bite in three cases, a human bite in one case, a motorcycle accident in one case, and finally, a burn trauma in two cases.
Objective. Three different cases of acquired marginal defects, namely ascending superior helix, descending helix, and cauda elicis with lobule involvement, are shown.
Methods. In the helix reconstruction, the tube width has not to be more than 15 mm, and the tube length has to be 1 cm longer than the defect. There was no conditioning of the flaps. No pedicle bridge was interposed along the major tube. The interval between two divisions was on average approximately 5 weeks.
Results. Seven patients were treated with this technique: In all cases, we had no infections or skin necrosis. To avoid a shrinkage of the tube, a correct ratio between flap dimensions and helical defect has to be estimated.
Conclusion. Although it is considered an old technique and it is a multistage reconstructive sequence, this procedure could be the first preference in cases of marginal defects more than 2.5 cm wide. This is because it restores naturally the anatomy of the helix.     

Lipid Raft Association Restricts CD44-Ezrin Interaction and Promotion of Breast Cancer Cell Migration

Cancer cell migration is an early event in metastasis, the main cause of breast cancer-related deaths. Cholesterol-enriched membrane domains called lipid rafts influence the function of many molecules, including the raft-associated protein CD44. We describe a novel mechanism whereby rafts regulate interactions between CD44 and its binding partner ezrin in migrating breast cancer cells. Specifically, in nonmigrating cells, CD44 and ezrin localized to different membranous compartments: CD44 predominantly in rafts, and ezrin in nonraft compartments. After the induction of migration (either nonspecific or CD44-driven), CD44 affiliation with lipid rafts was decreased. This was accompanied by increased coprecipitation of CD44 and active (threonine-phosphorylated) ezrin-radixin-moesin (ERM) proteins in nonraft compartments and increased colocalization of CD44 with the nonraft protein, transferrin receptor. Pharmacological raft disruption using methyl-β-cyclodextrin also increased CD44-ezrin coprecipitation and colocalization, further suggesting that CD44 interacts with ezrin outside rafts during migration. Conversely, promoting CD44 retention inside lipid rafts by pharmacological inhibition of depalmitoylation virtually abolished CD44-ezrin interactions. However, transient single or double knockdown of flotillin-1 or caveolin-1 was not sufficient to increase cell migration over a short time course, suggesting complex crosstalk mechanisms. We propose a new model for CD44-dependent breast cancer cell migration, where CD44 must relocalize outside lipid rafts to drive cell migration. This could have implications for rafts as pharmacological targets to down-regulate cancer cell migration.The membrane protein CD44 is a multifaceted molecule involved in many different cellular processes, including organ development, neuronal axon guidance, immune functions, hematopoiesis, and migration.^1–4 It acts as a receptor for the extracellular matrix component hyaluronic acid (HA)^5,6 and for the secreted extracellular protein osteopontin.⁷ CD44 is an important mediator of cellular adhesion and migration due to its active influence on the organization of the actin cytoskeleton. This occurs through direct interactions between CD44 and different actin-binding partners, of which the most common are proteins belonging to the ezrin-moesin-radixin (ERM) family. The ERM proteins form a bridge between CD44 and the actin cytoskeleton, mediating cell morphology changes that are important for cell migration. Ezrin interacts with CD44 and F-actin, respectively, through its conserved N-terminal band four-point-one, ezrin, radixin, moesin domain and C-terminal ERM Association Domain domain. In the inactive configuration of ezrin, both domains interact with each other and block the binding sites for CD44 and F-actin. Ezrin activation is mediated by phosphorylation-induced conformational changes,⁸ with phosphorylation on threonine-567 being necessary for binding to the F-actin cytoskeleton.⁹Phosphorylation of CD44 has also been shown to be important for its activation, particularly on serine residues in the C-terminal domain.^8,10 CD44 has been described to be enriched in cholesterol- and sphingomyelin-enriched membrane microdomains termed lipid rafts.¹¹ Much evidence has suggested the involvement of lipid rafts in regulating different cellular events, including migration.¹² Because some of these cellular events are frequently altered in cancer, it has been hypothesized that lipid rafts play a crucial role in regulating cancer progression.¹³ However, although alterations in CD44 expression have been associated with many cancers,¹⁴ how lipid rafts influence the subcellular localization (and thus migratory functions) of CD44 and its contribution toward cancer progression is not well understood.Whether or not CD44 and its binding partners localize to lipid rafts may in fact regulate several signaling cascades. CD44 is usually directed toward lipid rafts via posttranslational lipid modifications called acylation reactions, the most common of which is palmitoylation. Due to its dynamic and reversible nature, palmitoylation can have important functions in dictating protein fate such as protein trafficking, lateral segregation, and cellular localization. Palmitoylation plays an important role in CD44-HA turnover, with palmitoylated CD44 promoting CD44-HA endocytosis. Accordingly, lipid rafts have been described to play an important role in cellular endocytosis.¹⁵Ezrin localization to lipid rafts is controversial¹⁶ and the mechanisms regulating its affiliation with lipid rafts incompletely understood. Ezrin interactions with phosphatidylinositol 4,5-biphosphate (PIP2) may be important for its activation, causing the four-point-one and C-terminal ERM domains to open¹⁷ and permitting ezrin localization at the plasma membrane.¹⁸ Because PIP2 has been described to be enriched in lipid rafts,¹⁹ it is possible that ezrin localizes to lipid rafts through an interaction with PIP2.In this paper, we set out to investigate the role of lipid rafts in regulating CD44-dependent breast cancer cell migration. Our initial findings revealed that CD44 and ezrin localized to different membrane fractions in nonmigrating cells, biochemically characterized as lipid raft and nonraft domains, respectively. In response to migratory stimuli (either random or CD44-specific), the proportion of raft-affiliated CD44 decreased whereas that of ezrin did not change. Moreover, under migrating compared to nonmigrating conditions, immunofluorescence confocal microscopy revealed increased colocalization of CD44 with the nonraft marker transferrin receptor. Altogether, we present novel evidence that physical interactions between CD44 and ezrin occur in nonraft fractions of migrating cells. In support of our observations, pharmacological disruption of lipid rafts increased CD44-ezrin coprecipitation, whereas enhanced retention of CD44 within rafts abolished CD44-ezrin coprecipitation. Surprisingly, flotillin-1 or caveolin-1 transient knockdown alone did not affect cell migration in these cells, suggesting compensatory mechanisms that make up for the presumed loss of one or other raft compartment. In support of this assumption, coincident knockdown of flotillin-1 and caveolin-1 significantly impaired cell migration. Nonetheless, our data are consistent with a novel regulatory mechanism in which CD44 translocates outside lipid rafts to bind ERM binding partners such as ezrin and drive cell migration. Future exploration of the precise mechanisms regulating this translocation may reveal future targets for interfering with breast cancer cell migration during the early stages of metastasis.     

Approach to discover T- and B-cell antigens of intracellular pathogens applied to the design of Chlamydia trachomatis vaccines

Natural immunity against obligate and/or facultative intracellular pathogens is usually mediated by both humoral and cellular immunity. The identification of those antigens stimulating both arms of the immune system is instrumental for vaccine discovery. Although high-throughput technologies have been applied for the discovery of antibody-inducing antigens, few examples of their application for T-cell antigens have been reported. We describe how the compilation of the immunome, here defined as the pool of immunogenic antigens inducing T- and B-cell responses in vivo, can lead to vaccine candidates against Chlamydia trachomatis. We selected 120 C. trachomatis proteins and assessed their immunogenicity using two parallel high-throughput approaches. Protein arrays were generated and screened with sera from C. trachomatis-infected patients to identify antibody-inducing antigens. Splenocytes from C. trachomatis-infected mice were stimulated with 79 proteins, and the frequency of antigen-specific CD4(+)/IFN-γ(+) T cells was analyzed by flow cytometry. We identified 21 antibody-inducing antigens, 16 CD4(+)/IFN-γ(+)-inducing antigens, and five antigens eliciting both types of responses. Assessment of their protective activity in a mouse model of Chlamydia muridarum lung infection led to the identification of seven antigens conferring partial protection when administered with LTK63/CpG adjuvant. Protection was largely the result of cellular immunity as assessed by CD4(+) T-cell depletion. The seven antigens provided robust additive protection when combined in four-antigen combinations. This study paves the way for the development of an effective anti-Chlamydia vaccine and provides a general approach for the discovery of vaccines against other intracellular pathogens.     

Current trends and perspectives in interventional radiology for gastrointestinal cancers

Gastrointestinal (GI) cancers often require a multidisciplinary approach involving surgeons, endoscopists, oncologists, and interventional radiologists to diagnose and treat primitive cancers, metastases, and related complications. In this context, interventional radiology (IR) represents a useful minimally-invasive tool allowing to reach lesions that are not easily approachable with other techniques. In the last years, through the development of new devices, IR has become increasingly relevant in the context of a more comprehensive management of the oncologic patient. Arterial embolization, ablative techniques, and gene therapy represent useful and innovative IR tools in GI cancer treatment. Moreover, IR can be useful for the management of GI cancer-related complications, such as bleeding, abscesses, GI obstructions, and neurological pain. The aim of this study is to show the principal IR techniques for the diagnosis and treatment of GI cancers and related complications, as well as to describe the future perspectives of IR in this oncologic field.