Spontaneous subconjunctival orbital fat prolapse: presentation of four cases

BACKGROUND: Subconjunctival orbital fat prolapse is a benign entity characterized by orbital fat herniation through a dehiscence in Tenon's capsule, usually between the superior and lateral recti muscles. It is often associated with ocular trauma or surgery, although spontaneous cases have also been reported with a predilection for obese individuals. PATIENTS AND METHODS: A retrospective study of four subconjunctival orbital-fat prolapse cases with no history of ocular surgery or trauma was performed. A trans-conjunctival surgical approach with Tenon's capsule repair was offered to all subjects. Differential diagnosis is discussed. RESULTS: The diagnosis of subconjunctival orbital fat prolapse was confirmed in all cases by histopathological examination. Functional and aesthetic postoperative results were excellent, with no recurrences during follow-up, for all cases. CONCLUSIONS: Although rare, subconjunctival orbital fat prolapse should be recognized. Surgical management offers excellent results.

Current Molecular Imaging of Spinal Tumors in Clinical Practice.

Energy metabolism measurements in spinal cord tumors, as well as in osseous spinal tumors/metastasis in vivo, are rarely performed only with molecular imaging (MI) by positron emission tomography (PET). This imaging modality developed from a small number of basic clinical science investigations followed by subsequent work that influenced and enhanced the research of others. Apart from precise anatomical localization by coregistration of morphological imaging and quantification, the most intriguing advantage of this imaging is the opportunity to investigate the time course (dynamics) of disease-specific molecular events in the intact organism. Most importantly, MI represents one of the key technologies in translational molecular neuroscience research, helping to develop experimental protocols that may later be applied to human patients. PET may help monitor a patient at the vertebral level after surgery and during adjuvant treatment for recurrent or progressive disease. Common clinical indications for MI of primary or secondary CNS spinal tumors are: (i) tumor diagnosis, (ii) identification of the metabolically active tumor compartments (differentiation of viable tumor tissue from necrosis) and (iii) prediction of treatment response by measurement of tumor perfusion or ischemia. While spinal PET has been used under specific circumstances, a question remains as to whether the magnitude of biochemical alterations observed by MI in CNS tumors in general (specifically spinal tumors) can reveal any prognostic value with respect to survival. MI may be able to better identify early disease and to differentiate benign from malignant lesions than more traditional methods. Moreover, an adequate identification of treatment effectiveness may influence patient management. MI probes could be developed to image the function of targets without disturbing them or as treatment to modify the target's function. MI therefore closes the gap between in vitro and in vivo integrative biology of disease. At the spinal level, MI may help to detect progression or recurrence of metastatic disease after surgical treatment. In cases of nonsurgical treatments such as chemo-, hormone- or radiotherapy, it may better assess biological efficiency than conventional imaging modalities coupled with blood tumor markers. In fact, PET provides a unique possibility to correlate topography and specific metabolic activity, but it requires additional clinical and experimental experience and research to find new indications for primary or secondary spinal tumors.

Molecular detection and identification of zygomycetes species from paraffin-embedded tissues in a murine model of disseminated zygomycosis: a collaborative European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Fungal Infection Study Group (EFISG) evaluation.

The present study was performed to assess the interlaboratory reproducibility of the molecular detection and identification of species of Zygomycetes from formalin-fixed paraffin-embedded kidney and brain tissues obtained from experimentally infected mice. Animals were infected with one of five species (Rhizopus oryzae, Rhizopus microsporus, Lichtheimia corymbifera, Rhizomucor pusillus, and Mucor circinelloides). Samples with 1, 10, or 30 slide cuts of the tissues were prepared from each paraffin block, the sample identities were blinded for analysis, and the samples were mailed to each of seven laboratories for the assessment of sensitivity. A protocol describing the extraction method and the PCR amplification procedure was provided. The internal transcribed spacer 1 (ITS1) region was amplified by PCR with the fungal universal primers ITS1 and ITS2 and sequenced. As negative results were obtained for 93% of the tissue specimens infected by M. circinelloides, the data for this species were excluded from the analysis. Positive PCR results were obtained for 93% (52/56), 89% (50/56), and 27% (15/56) of the samples with 30, 10, and 1 slide cuts, respectively. There were minor differences, depending on the organ tissue, fungal species, and laboratory. Correct species identification was possible for 100% (30 cuts), 98% (10 cuts), and 93% (1 cut) of the cases. With the protocol used in the present study, the interlaboratory reproducibility of ITS sequencing for the identification of major Zygomycetes species from formalin-fixed paraffin-embedded tissues can reach 100%, when enough material is available.

Serum uric acid and gout: from the past to molecular biology.

Abstract Objectives: This review will briefly present the epidemiology and risk factors of gout, with a focus on recent advances. Methods: Key papers for inclusion were identified by a PubMed search, and articles were selected according to their relevance for the topic, according to authors' judgment. Results and conclusions: Gout therapy has remained very much unchanged for the last 50 years, but recently we have seen the approval of another gout treatment: the xanthine oxidase inhibitor febuxostat, and several new drugs are now in the late stages of clinical testing. Together with our enhanced level of understanding of the pathophysiology of the inflammatory process involved, we are entering a new era for the treatment of gout.

Role of the stress sigma factor RpoS in GacA/RsmA-controlled secondary metabolism and resistance to oxidative stress in Pseudomonas fluorescens CHA0.

In Pseudomonas fluorescens biocontrol strain CHA0, the two-component system GacS/GacA positively controls the synthesis of extracellular products such as hydrogen cyanide, protease, and 2,4-diacetylphloroglucinol, by upregulating the transcription of small regulatory RNAs which relieve RsmA-mediated translational repression of target genes. The expression of the stress sigma factor sigmaS (RpoS) was controlled positively by GacA and negatively by RsmA. By comparison with the wild-type CHA0, both a gacS and an rpoS null mutant were more sensitive to H2O2 in stationary phase. Overexpression of rpoS or of rsmZ, encoding a small RNA antagonistic to RsmA, restored peroxide resistance to a gacS mutant. By contrast, the rpoS mutant showed a slight increase in the expression of the hcnA (HCN synthase subunit) gene and of the aprA (major exoprotease) gene, whereas overexpression of sigmaS strongly reduced the expression of these genes. These results suggest that in strain CHA0, regulation of exoproduct synthesis does not involve sigmaS as an intermediate in the Gac/Rsm signal transduction pathway whereas sigmaS participates in Gac/Rsm-mediated resistance to oxidative stress.

Molecular pathology of colorectal cancer.

Colorectal cancer (CRC) is one of the most intensively studied cancer types, partly because of its high prevalence but also because of the existence of its precursor lesions, tubular or villous adenomas, and more recently (sessile) serrated adenomas, which can be detected endoscopically and removed. The morphological steps in the adenoma-carcinoma sequence have been elucidated at a molecular level, which has been facilitated by identification of the genes responsible for familial intestinal cancer. However, apart from early detection of familial forms of CRC and its use in genetic counseling, until recently such detailed molecular knowledge has had little impact on clinical management of the disease. This has dramatically changed in the last decade. With drugs specifically targeting the epidermal growth factor receptor (EGFR) having been shown effective in CRC, mechanisms responsible for resistance have been explored. The finding that KRAS mutated cancers do not respond to anti-EGFR treatment has had a profound impact on clinical management and on molecular diagnostics of CRC. Additional genetic tests for mutations in NRAS, BRAF and PIK3CA contribute to determining who to treat, and others will follow. New therapies effective in patients with advanced CRC are under investigation. Remaining burning questions for optimal management are which patients will relapse after resection of the primary tumor and which patients will respond to the standard 5FU-oxaliplatin adjuvant treatment regimen. Predictive tests to address these issues are eagerly awaited. New classifications of CRC, based on molecular parameters, are emerging, and we will be confronted with new subtypes of CRC, for which the definition is based on combinations of gene expression patterns, chromosomal alterations, gene mutations and epigenetic characteristics. This will be instrumental in designing new approaches for therapy but will also be translated into molecular diagnostics. Both will contribute to improved clinical management of CRC.

Molecular characterization and phenotypic expression of mutations in genes for gonadotropins and their receptors in humans.

Gonadotropin hormones undergo important dynamic changes during life. Their rise during puberty stimulates gonadal steroid secretion, triggering the development of secondary sexual characteristics and the acquisition of fertility. The full spectrum of possible mutations and polymorphisms in the human gonadotropins and in their receptor genes has been described in recent years. Patients harboring these mutations display a very wide range of phenotypes affecting all aspects of the reproductive axis. An important insight provided by the careful study of these patients lies in the striking gender differences in the phenotypes associated with a given mutation. As a result, the careful study of these rare patients has allowed us to better define the respective roles of luteinizing hormone and follicle-stimulating hormone in normal human pubertal development and in the achievement of full fertility potential in either males or females. In this work, we describe briefly the known mutations in the genes for both gonadotropins and their receptors, and discuss their genotype/phenotype correlations in light of these important gender differences.

Molecular characterization of chromosome termini of the arbuscular mycorrhizal fungus Glomus intraradices (Glomeromycota).

The minimum chromosome number of Glomus intraradices was assessed through cloning and sequencing of the highly divergent telomere-associated sequences (TAS) and by pulsed field gel electrophoresis (PFGE). The telomere of G. intraradices, as in other filamentous fungi, consists of TTAGGG repeats, this was confirmed using Bal31 nuclease time course reactions. Telomere length was estimated to be roughly 0.9 kb by Southern blots on genomic DNA and a telomere probe. We have identified six classes of cloned chromosomal termini based on the TAS. An unusually high genetic variation was observed within two of the six TAS classes. To further assess the total number of chromosome termini, we used telomere fingerprinting. Surprisingly, all hybridization patterns showed smears, which demonstrate that TAS are remarkably variable in the G. intraradices genome. These analyses predict the presence of at least three chromosomes in G. intraradices while PFGE showed a pattern of four bands ranging from 1.2 to 1.5 Mb. Taken together, our results indicate that there are at least four chromosomes in G. intraradices but there are probably more. The information on TAS and telomeres in the G. intradicies will be essential for making a physical map of the G. intraradices genome and could provide molecular markers for future studies of genetic variation among nuclei in these multigenomic fungi.

Methicillin-resistant Staphylococcus aureus infection after lung transplantation: 5-year review of clinical and molecular epidemiology.

BACKGROUND: Data on the epidemiology of MRSA infection in lung transplantation is limited. METHODS: We performed a 5-year retrospective study to assess the incidence and microbiologic and clinical characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in a cohort of 163 lung transplant recipients. RESULTS: Seventeen patients with MRSA colonization and/or infection were identified, for a calculated incidence rate of 76.1 cases per 1,000 transplanted-years. Pulsed-field gel electrophoresis identified 3 different distinct MRSA profiles, all of them consistent with hospital-associated MRSA infection. CONCLUSION: Despite negative polymerase chain reaction (PCR) for the virulence factor Panton-Valentine leukocidin, MRSA infections resulted in significant disease and morbidity.

Serrated polyps of the large intestine: a molecular study comparing sessile serrated adenomas and hyperplastic polyps.

AIMS: To compare the molecular profile of a series of sessile serrated adenomas (SSAs) and hyperplastic polyps (HPs), in order to distinguish these lesions, SSAs having a potential role in the genesis of serrated adenocarcinomas through a serrated pathway in which methylation plays a key role. METHODS AND RESULTS: Twelve HPs and sixteen SSAs of the right and left colon were investigated for microsatellite instability, DNA mismatch repair genes, p53, p16, and beta-catenin expression, MLH1 and p16 (CDKN2A) gene methylation, and KRAS and BRAF mutations. Both SSAs and HPs were microsatellite stable. MLH1 and MSH2 protein silencing, aberrant cytoplasmic expression and methylation of p16 were found to be exclusive to right-sided SSAs. The MLH1 promoter gene was frequently methylated in right-sided SSAs in contrast with HPs. Abnormal p53 and beta-catenin expression was present in both SSAs and HPs. BRAF and KRAS mutation were mutually exclusive, but KRAS mutation was present only in left-sided SSAs and HPs. CONCLUSIONS: HPs and SSAs may be related lesions. However, at least right-sided SSAs differ from left-sided SSAs and HPs in the occurrence of MLH1 and p16 methylation, supporting the hypothesis that SSAs could be precursors of serrated adenocarcinomas.

Fifteen years of molecular lymphangiogenesis - an interview with Kari Alitalo by Tatiana Petrova.

Kari Alitalo is one of the leaders in the field of lymphangiogenesis. Research from his laboratory has contributed to the transformation of a largely descriptive field into a dynamic discipline, which now holds promise for the treatment of cancer, inflammation and vascular dysfunction. The interview intends to provide historical insights into these changes and hopefully inspiration to the young generation of vascular biologists.

The complement inhibitor low molecular weight dextran sulfate prevents TLR4-induced phenotypic and functional maturation of human dendritic cells.

Low molecular weight dextran sulfate (DXS) has been reported to inhibit the classical, alternative pathway as well as the mannan-binding lectin pathway of the complement system. Furthermore, it acts as an endothelial cell protectant inhibiting complement-mediated endothelial cell damage. Endothelial cells are covered with a layer of heparan sulfate (HS), which is rapidly released under conditions of inflammation and tissue injury. Soluble HS induces maturation of dendritic cells (DC) via TLR4. In this study, we show the inhibitory effect of DXS on human DC maturation. DXS significantly prevents phenotypic maturation of monocyte-derived DC and peripheral myeloid DC by inhibiting the up-regulation of CD40, CD80, CD83, CD86, ICAM-1, and HLA-DR and down-regulates DC-SIGN in response to HS or exogenous TLR ligands. DXS also inhibits the functional maturation of DC as demonstrated by reduced T cell proliferation, and strongly impairs secretion of the proinflammatory mediators IL-1beta, IL-6, IL-12p70, and TNF-alpha. Exposure to DXS leads to a reduced production of the complement component C1q and a decreased phagocytic activity, whereas C3 secretion is increased. Moreover, DXS was found to inhibit phosphorylation of IkappaB-alpha and activation of NF-kappaB. These findings suggest that DXS prevents TLR-induced maturation of human DC and may therefore be a useful reagent to impede the link between innate and adaptive immunity.

Molecular determinants for membrane association of the hepatitis C virus NS2 protease domain

Background: Hepatitis C virus (HCV) nonstructural protein 2 (NS2) plays essential roles in particle assembly and polyprotein processing. It harbors an N-terminal membrane domain comprising three putative transmembrane s egments ( amino acids [aa] 1-93) a nd a C-terminal cysteine protease domain (aa 94-217). Given that the latter has been predicted to be membrane-associated, we aimed to identify molecular determinants for membrane association of the NS2 protease domain. Methods: A comprehensive panel of NS2 deletion constructs was analyzed by fluorescence microscopy, selective membrane extraction, and m embrane flotation assays. Candidate aa r esidues involved in membrane association were substituted by site-directed mutagenesis. Results: The NS2 protease domain alone was found to associate with membranes. Two N-terminal α-helices comprising aa 102-114 and aa 123-136 were found to m ediate this a ssociation, w ith c onserved hydrophobic and positively charged aa residues representing the key determinants. I nterestingly, m utagenesis analyses r evealed that electrostatic interactions involving a positively charged aa residue in α-helix aa 123-136 are required for membrane association. Mono- and bicistronic (i.e. NS2 c leavage-independent) HCV constructs were prepared to i nvestigate the effect o f these substitutions on RNA replication and infectious viral particle formation. Conclusions: T he NS2 protease d omain itself harbors m olecular determinants for membrane association within α-helices aa 102-114 and aa 1 23-136 which may contribute to p roper p ositioning of t he active site. These results provide new insights i nto the membrane topology and t he p oorly understood f unction of t his essential viral protease.

A molecular framework for light and gibberellin control of cell elongation.

Cell elongation during seedling development is antagonistically regulated by light and gibberellins (GAs). Light induces photomorphogenesis, leading to inhibition of hypocotyl growth, whereas GAs promote etiolated growth, characterized by increased hypocotyl elongation. The mechanism underlying this antagonistic interaction remains unclear. Here we report on the central role of the Arabidopsis thaliana nuclear transcription factor PIF4 (encoded by PHYTOCHROME INTERACTING FACTOR 4) in the positive control of genes mediating cell elongation and show that this factor is negatively regulated by the light photoreceptor phyB (ref. 4) and by DELLA proteins that have a key repressor function in GA signalling. Our results demonstrate that PIF4 is destabilized by phyB in the light and that DELLAs block PIF4 transcriptional activity by binding the DNA-recognition domain of this factor. We show that GAs abrogate such repression by promoting DELLA destabilization, and therefore cause a concomitant accumulation of free PIF4 in the nucleus. Consistent with this model, intermediate hypocotyl lengths were observed in transgenic plants over-accumulating both DELLAs and PIF4. Destabilization of this factor by phyB, together with its inactivation by DELLAs, constitutes a protein interaction framework that explains how plants integrate both light and GA signals to optimize growth and development in response to changing environments.