Testing Critical Slowing Down as a Bifurcation Indicator in a Low-Dissipation Dynamical System.

We study a two-dimensional low-dissipation nonautonomous dynamical system, with a control parameter that is swept linearly in time across a transcritical bifurcation. We investigate the relaxation time of a perturbation applied to a variable of the system and we show that critical slowing down may occur at a parameter value well above the bifurcation point. We test experimentally the occurrence of critical slowing down by applying a perturbation to the accessible control parameter and we find that this perturbation leaves the system behavior unaltered, thus providing no useful information on the occurrence of critical slowing down. The theoretical analysis reveals the reasons why these tests fail in predicting an incoming bifurcation.

Chiral x achiral multidimensional liquid chromatography. Application to the enantioseparation of dintitrophenyl amino acids in honey samples and their fingerprint classification.

Most HPLC enantiomer separations are performed with columns packed with a chiral stationary phase (CSP) operated with an achiral mobile phase. The intrinsically limited chemical selectivity of most CSPs to the simultaneous resolution of several pairs of enantiomers means that complex mixtures of diverse pairs of enantiomers cannot be resolved in a single run due to peak overlapping. Moreover, some drawbacks remain when the analyte is present in very complex samples containing other achiral compounds which can co-elute with the enantiomer peaks. Multidimensional chromatography becomes an option to increase peak capacity and resolve these samples. The aim of this work was to study an online fully comprehensive 2D-LC mode utilizing a combination of a chiral column in the first dimension and an achiral column in the second dimension. The 2D-LC system was built with an active flow splitter pump in order to easily adjust the volume of sample transferred into the second dimension and to independently optimize the flow rate in the first dimension. The present LCxLC method was optimized for the separation of amino acids present in honey samples, taking into account key parameters that influence the bidimensional peak capacity (orthogonality, sampling frequency, etc.). The amino acids have been preconcentrated on a cation-exchange column followed by derivatization. Several amino acids present in different honey samples have been identified and the data generated has been analyzed by principal component analysis.

High throughput method to characterize acid-base properties of insoluble drug candidates in water.

In drug design experimental characterization of acidic groups in candidate molecules is one of the more important steps prior to the in-vivo studies. Potentiometry combined with Yasuda-Shedlovsky extrapolation is one of the more important strategy to study drug candidates with low solubility in water, although, it requires a large number of sequences to determine pKa values at different solvent-mixture compositions to, finally, obtain the pKa in water (pwwKa) by extrapolation. We have recently proposed a method which requires only two sequences of additions to study the effect of organic solvent content in liquid chromatography mobile phases on the acidity of the buffer compounds usually dissolved in it along wide ranges of compositions. In this work we propose to apply this method to study thermodynamic pwwKa of drug candidates with low solubilities in pure water. Using methanol/water solvent mixtures we study six pharmaceutical drugs at 25 °C. Four of them: ibuprofen, salicylic acid, atenolol and labetalol, were chosen as members of carboxylic, amine and phenol families, respectively. Since these compounds have known pwwKa values, they were used to validate the procedure, the accuracy of Yasuda-Shedlovsky and other empirical models to fit the behaviors, and to obtain pwwKa by extrapolation. Finally, the method is applied to determine unknown thermodynamic pwwKa values of two pharmaceutical drugs: atorvastatin calcium and the two dissociation constants of ethambutol. The procedure proved to be simple, very fast and accurate in all of the studied cases.

Quercetin reduced inflammation and increased antioxidant defense in rat adjuvant arthritis.

Novel therapies for rheumatoid arthritis also include the use of naturally occurring compounds possessing antioxidant properties. In the present work, the effects of oral administration of quercetin were investigated in a rat model of adjuvant arthritis. Arthritis was induced by a single intradermal injection of heat-inactivated Mycobacterium butyricum in incomplete Freund's adjuvant. The experimental groups were treated with an oral daily dose of 150 mg/kg b.w. of quercetin for 28 days. Results indicated that quercetin was able to ameliorate all markers of inflammation and oxidative stress measured. Quercetin lowered levels of interleukin-1ß, C-reactive protein, and monocyte chemotactic protein-1 and restored plasma antioxidant capacity. In addition, quercetin inhibited the enzymatic activity of pro-inflammatory 12/15-lipoxygenase in lung and liver and increased the expression of heme oxygenase-1 in joint and lung of arthritic rats. Finally, quercetin inhibited the 2-fold increase of NF-қB activity observed in lung, liver and joint after induction of arthritis.

A novel patient-derived tumorgraft model with TRAF1-ALK anaplastic large-cell lymphoma translocation.

Although anaplastic large-cell lymphomas (ALCL) carrying anaplastic lymphoma kinase (ALK) have a relatively good prognosis, aggressive forms exist. We have identified a novel translocation, causing the fusion of the TRAF1 and ALK genes, in one patient who presented with a leukemic ALK+ ALCL (ALCL-11). To uncover the mechanisms leading to high-grade ALCL, we developed a human patient-derived tumorgraft (hPDT) line. Molecular characterization of primary and PDT cells demonstrated the activation of ALK and nuclear factor kB (NFkB) pathways. Genomic studies of ALCL-11 showed the TP53 loss and the in vivo subclonal expansion of lymphoma cells, lacking PRDM1/Blimp1 and carrying c-MYC gene amplification. The treatment with proteasome inhibitors of TRAF1-ALK cells led to the downregulation of p50/p52 and lymphoma growth inhibition. Moreover, a NFkB gene set classifier stratified ALCL in distinct subsets with different clinical outcome. Although a selective ALK inhibitor (CEP28122) resulted in a significant clinical response of hPDT mice, nevertheless the disease could not be eradicated. These data indicate that the activation of NFkB signaling contributes to the neoplastic phenotype of TRAF1-ALK ALCL. ALCL hPDTs are invaluable tools to validate the role of druggable molecules, predict therapeutic responses and implement patient specific therapies.

Automatized sspKa measurements of dihydrogen phosphate and Tris(hydroxymethyl) aminomethane in acetonitrile/water mixtures from 20 to 60°C.

We measured pKa values of Tris(hydroxymethyl)aminomethane and dihydrogen phosphate; both are commonly used to prepare buffers for reverse-phase liquid chromatography (RPLC), in acetonitrile/water mixtures from 0% to 70% (v/v) (64.6% (w/w)) acetonitrile and at 20, 30, 40, 50, and 60°C. The procedure is based on potentiometric measurements of pH of buffer solutions of variable solvent compositions using a glass electrode and a novel automated system. The method consists in the controlled additions of small volumes of a thermostated solution from an automatic buret into another isothermal solution containing exactly the same buffer-component concentrations, but a different solvent composition. The continuous changes in the solvent composition induce changes in the potentials. Thus, only two sequences of additions are needed: increasing the amount of acetonitrile from pure water and decreasing the content of acetonitrile from 70% (v/v) (64.6% (w/w)). In the procedure with homemade apparatus, times for additions, stirring, homogenization, and data acquisition are entirely controlled by software programmed for this specific routine. This rapid, fully automated method was applied to acquire more than 40 potential data covering the whole composition range (at each temperature) in about two hours and allowed a systematic study of the effect of temperature and acetonitrile composition on acid-base equilibria of two widely used substances to control pH close to 7. The experimental pKa results were fitted to empirical functions between pKa and temperature and acetonitrile composition. These equations allowed predictions of pKa to estimate the pH of mixtures at any composition and temperature, which would be very useful, for instance, during chromatographic method development.

Automated segmentation of tissue images for computerized IHC analysis.

This paper presents two automated methods for the segmentation of immunohistochemical tissue images that overcome the limitations of the manual approach as well as of the existing computerized techniques. The first independent method, based on unsupervised color clustering, recognizes automatically the target cancerous areas in the specimen and disregards the stroma; the second method, based on colors separation and morphological processing, exploits automated segmentation of the nuclear membranes of the cancerous cells. Extensive experimental results on real tissue images demonstrate the accuracy of our techniques compared to manual segmentations; additional experiments show that our techniques are more effective in immunohistochemical images than popular approaches based on supervised learning or active contours. The proposed procedure can be exploited for any applications that require tissues and cells exploration and to perform reliable and standardized measures of the activity of specific proteins involved in multi-factorial genetic pathologies.

Achieving the way for automated segmentation of nuclei in cancer tissue images through morphology-based approach: a quantitative evaluation.

In this paper we address the problem of nuclear segmentation in cancer tissue images, that is critical for specific protein activity quantification and for cancer diagnosis and therapy. We present a fully automated morphology-based technique able to perform accurate nuclear segmentations in images with heterogeneous staining and multiple tissue layers and we compare it with an alternate semi-automated method based on a well established segmentation approach, namely active contours. We discuss active contours' limitations in the segmentation of immunohistochemical images and we demonstrate and motivate through extensive experiments the better accuracy of our fully automated approach compared to various active contours implementations.

Retinoblastoma and mental retardation microdeletion syndrome: clinical characterization and molecular dissection using array CGH.

We describe three patients with retinoblastoma, dysmorphic features and developmental delay. Patients 1 and 2 have high and broad forehead, deeply grooved philtrum, thick anteverted lobes and thick helix. Patient 1 also has dolicocephaly, sacral pit/dimple and toe crowding; patient 2 shows intrauterine growth retardation and short fifth toe. Both patients have partial agenesis of corpus callosum. Patient 3 has growth retardation, microcephaly, thick lower lip and micrognathia. Using array-comparative genomic hybridization (CGH), we identified a 13q14 de novo deletion in patients 1 and 2, while patient 3 had a 7q11.21 maternally inherited deletion, probably not related to the disease. Our results confirm that a distinct facial phenotype is related to a 13q14 deletion. Patients with retinoblastoma and malformations without a peculiar facial phenotype may have a different deletion syndrome or a casual association of mental retardation and retinoblastoma. Using array-CGH, we defined a critical region for mental retardation and dysmorphic features. We compared this deletion with a smaller one in a patient with retinoblastoma (case 4) and identified two distinct critical regions, containing 30 genes. Four genes appear to be good functional candidates for the neurological phenotype: NUFIP1 (nuclear fragile X mental retardation protein 1), HTR2A (serotonin receptor 2A), PCDH8 (prothocaderin 8) and PCDH17 (prothocaderin 17).

Mortality from second tumour among long-term survivors of retinoblastoma: a retrospective analysis of the Italian retinoblastoma registry.

Survivors of retinoblastoma (Rb) are at high risk of dying from second malignant tumour. The occurrence of second malignant neoplasm (SMN) and related mortality in a cohort of 1111 cases from the Italian Retinoblastoma Registry was analysed, considering the possible role of both genetic and iatrogenic causes. Rb patients had a greater than 10-fold excess in overall mortality compared with the general population (standardized mortality ratio (SMR) 10.73, 95% CI 9.00-12.80). Their excess risk attributable to cancers other than Rb was 14.93 95% CI 10.38-21.49). Survivors of hereditary Rb had an SMR for all causes of 16.25 (95% CI 13.20-20.00), whereas their SMR for all cancers was 25.72 (95% CI 17.38-38.07). Survivors of unilateral sporadic Rb had an SMR of 4.12 from all cancers (95% CI 1.55-10.98) and a much higher excess for overall mortality (SMR 13.34, 95% CI 10.74-16.56). As expected, survivors of hereditary Rb had higher mortality from cancers of the bone (SMR 391.90, 95% CI 203.90-753.20) and soft tissue (SMR 453.00, 95% CI 203.50-1008.40), small intestine (SMR 1375.50, 95% CI 344.00-5499.70), nasal cavity (SMR 13.71, 95% CI 1.93-97.35) and cancers of the brain and central nervous system (SMR 41.14, 95% CI 13.2-127.55).

Cytotoxicity in vitro analysis of ceramic materials for ''metal free'' prosthetic substructures.

AIM: The aim of this study was to investigate the in vitro cytotoxicity of 5 ceramic materials for metal-free fixed prosthodontics: In-Ceram, Cergo, IPS Empress II, Cercon ZrO2, Finesse All Ceram compared each other and to commercially pure Titanium (CpTi). METHODS: The materials, prepared directly from manufacturers as 10 mm diameter and 3 mm thickness disks, have been tested following the ISO 10993-l guidelines, performing the in vitro cytotoxicity test with the use of mouse's cells, fibroblasts L-929, isolated by muscular tissue and cultured in an appropriate medium. The MTT test has been used to evaluate the cell viability through the succinate dehydrogenase enzyme activity. The originality of this investigation is that all the materials examined have been tested under the same conditions: the cytotoxicity test has been performed on these materials at the same time, in the same period, under the same conditions of temperature and humidity and by the same operator. RESULTS: Not all tested materials were free from cytotoxicity. Cercon, within the limits of this in vitro study, showed the lower cytotoxicity. CONCLUSIONS: This in vitro study suggested that ceramic materials for metal free prosthetic substructures are in competition with the CpTi which is very used in implant prosthodontics.

Nonsteroidal anti-inflammatory drugs in colorectal cancer: from prevention to therapy.

In this review, we discuss the available experimental evidences supporting the chemopreventive efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) on colorectal cancer and the biological basis for their possible role as anticancer agents. Although the comprehension of the mechanisms underlying the effects of these drugs on colon cancer cells is incomplete, research efforts in identifying the biochemical pathway by which NSAIDs exert their chemopreventive effect have provided a rationale for the potential use of NSAIDs alone or in combination with conventional and experimental anticancer agents in the treatment of colorectal cancer. In this paper, we review three main issues: (i) the role of COX-2 in colon cancer; (ii) the common death pathways between NSAIDs and anticancer drugs; and (iii) the biological basis for the combination therapy with COX-2 selective inhibitors and new selective inhibitors of growth factor signal transduction pathways.

Non-Hodgkin lymphoma in a child presenting with acute paraplegia: a case report.

Spinal cord compression is a rare presentation of non-Hodgkin lymphoma. Extradural location at onset is a rare but devastating event in pediatric oncology. The authors describe a girl with acute spinal cord compression due to epidural non-Hodgkin lymphoma, emphasizing the encouraging perspective for a complete recovery in children with this condition. A 5-year-old girl presented with pain followed by progressive hyposthenia and paraplegia after a trauma. CT scan and MRI showed homogeneous tissue extending from T2 to L4, occupying the entire vertebral canal and extending to the para- and peri-vertebral soft parts. Emergency surgical debulking was carried out through T6-L1 laminectomy. The patient began chemotherapy (LMB 89 Protocol) and the tumor quickly disappeared. The patient is maintaining a complete remission 42 months after diagnosis. Significant results may be obtained with the chemotherapy treatment of epidural non-Hodgkin lymphoma when the disease is promptly diagnosed. Considering the effectiveness of chemotherapy, the authors believe that a neuro-surgical approach should be employed only when rapid worsening of symptoms is observed or for diagnostic purpose.

Central precocious puberty in multisystem Langerhans cell histiocytosis: a case report.

The authors describe a girl with multisystem Langerhans cell histiocytosis (LCH) who developed central precocious puberty (CPP). At the age of 19 months she presented with otorrhea and polypoid formations in the ear canal; polyps were removed and LCH suspected. She subsequently developed diabetes insipidus with a documented lesion of the pituitary stalk; she received chemotherapy and began therapy with l-desamino-8-D-argininevasopressin. Growth hormone deficiency was diagnosed at the age of 4.4 years and GH replacement therapy started. The patient has been off therapy for LCH since the age of 6. Signs of pubertal development appeared at 7.5 years (bone age 8 years) and gonadotropin-releasing hormone analog (GnRHa) treatment was started. During the observation period she developed central hypothyroidism. Development of CPP during LCH is extremely rare; to the authors 'knowledge, no patient has been described so far. The authors believe that CPP was secondary to LCH and did not represent a casual finding, even in the absence of hypothalamic-pituitary axis involvement. The presence of preceding lesions producing excessive cytokine levels, with damage on the neurosecretory apparatus that inhibits the GnRH pulse generator, represents the most intriguing hypothesis. The possibility of CPP development should be considered during the follow-up of these patients.

Effect of non-steroidal anti-inflammatory drugs on colon carcinoma Caco-2 cell responsiveness to topoisomerase inhibitor drugs.

Numerous studies demonstrate that the chemopreventive effect of non-steroidal anti-inflammatory drugs on colon cancer is mediated through inhibition of cell growth and induction of apoptosis. For these effects non-steroidal anti-inflammatory drugs have been recently employed as sensitising agents in chemotherapy. We have shown previously that treatments with aspirin and NS-398, a cyclo-oxygenase-2 selective inhibitor, affect proliferation, differentiation and apoptosis of the human colon adenocarcinoma Caco-2 cells. In the present study, we have evaluated the effects of aspirin and NS-398 non-steroidal anti-inflammatory drugs on sensitivity of Caco-2 cells to irinotecan (CPT 11) and etoposide (Vp-16) topoisomerase poisons. We find that aspirin co-treatment is able to prevent anticancer drug-induced toxicity, whereas NS-398 co-treatment poorly affects anticancer drug-induced apoptosis. These effects correlate with the different ability of aspirin and NS-398 to interfere with cell cycle during anticancer drug co-treatment. Furthermore, aspirin treatment is associated with an increase in bcl-2 expression, which persists in the presence of the anticancer drugs. Our data indicate that aspirin, but not NS-398, determines a cell cycle arrest associated with death suppression. This provides a plausible mechanism for the inhibition of apoptosis and increase in survival observed in anticancer drug and aspirin co-treatment.

IGF-II/IGF-I receptor pathway up-regulates COX-2 mRNA expression and PGE2 synthesis in Caco-2 human colon carcinoma cells.

Nonsteroidal anti-inflammatory drugs reduce the risk of colon cancer and this effect is mediated in part through inhibition of type 2 prostaglandin endoperoxide synthase/ cyclo-oxygenase (COX-2). In the present study, we demonstrate that COX-2 expression and PGE2 synthesis are up-regulated by an IGF-II/IGF-I receptor autocrine pathway in Caco-2 colon carcinoma cells. COX-2 mRNA and PGE2 levels are higher in proliferating cells compared with post-confluent differentiated cells and in cells that constitutively overexpress IGF-II. Up-regulation of COX-2 expression by IGF-II is mediated through activation of IGF-I receptor because: (i) treatment of Caco-2 cells with a blocking antibody to the IGF-I receptor inhibits COX-2 mRNA expression; (ii) transfection of Caco-2 cells with a dominant negative IGF-I receptor reduces COX-2 expression and activity. Also, the blockade of the PI3-kinase, that mediates the proliferative effect of IGF-I receptor in Caco-2 cells, inhibits IGF-II-dependent COX-2 up-regulation and PGE2 synthesis. Moreover, COX-2 expression and activity inversely correlate with the increase of apoptosis in parental, IGF-II and dominant-negative IGF-I receptor transfected cells. This study suggests that induction of proliferation and tumor progression of colon cancer cells by the IGF-II/IGF-I receptor pathway may depend on the activation of COX-2-related events.

Vagal and hypoglossal Bell's palsy.

A 7-year-old boy was referred because of a sudden change to nasal speech, dysarthria for words with explosive consonants in speech, and nasal regurgitation of fluids. The symptoms arose over 1 week following a capricious episode of acute asthmatic bronchitis. Physical and neurologic examinations were normal except for a left deviation of the uvula, accompanied by a "curtain" movement of the posterior pharyngeal wall against the opposite side, and a left deviation of the protruded tongue. No vascular, traumatic, infectious, neoplastic, or neurologic causes could be identified. No therapy was administered. Full recovery occurred 4 months later. The diagnosis was idiopathic vagal and right hypoglossal nerve palsy (Bell's palsy).

Plasmapheresis in a child affected by acute disseminated encephalomyelitis.

We describe an eight year old girl with acute relapsing disseminated encephalomyelitis (ADEM) who began to improve concomitantly with plasmapheresis therapy. The patient had previously undergone high-dose intravenous methylprednisolone, intravenous immunoglobulins and Interferon beta-1b treatment which did not control the clinical course of the disease. The long term follow-up suggests that plasmapheresis is effective in this disorder and may give better results than steroids or IVIG.