Cell cycle analysis can differentiate thin melanomas from dysplastic nevi and reveals accelerated replication in thick melanomas

Cell replication integrates aberrations of cell cycle regulation and diverse upstream pathways which all can contribute to melanoma development and progression. In this study, cell cycle regulatory proteins were detected in situ in benign and malignant melanocytic tumors to allow correlation of major cell cycle fractions (G1, S-G2, and G2-M) with melanoma evolution. Dysplastic nevi expressed early cell cycle markers (cyclin D1 and cyclin-dependent kinase 2; Cdk2) significantly more (p?<?0.05) than common nevi. Post-G1 phase markers such as cyclin A, geminin, topoisomerase IIα (peaking at S-G2) and aurora kinase B (peaking at G2-M) were expressed in thin (≤1 mm) melanomas but not in dysplastic nevi, suggesting that dysplastic melanocytes engaged in the cell cycle do not complete replication and remain arrested in G1 phase. In malignant melanomas, the expression of general and post-G1 phase markers correlated well with each other implying negligible cell cycle arrest. Post-G1 phase markers and Ki67 but none of the early markers cyclin D1, Cdk2 or minichromosome maintenance protein 6 (Mcm6) were expressed significantly more often in thick (>1 mm) than in thin melanomas. Marker expression did not differ between metastatic melanomas and thick melanomas, with the exception of aurora kinase A of which the expression was higher in metastatic melanomas. Combined detection of cyclin A (post-G1 phase) with Mcm6 (replication licensing) and Ki67 correctly classified thin melanomas and dysplastic nevi in 95.9 % of the original samples and in 93.2 % of cross-validated grouped cases at 89.5 % sensitivity and 92.6 % specificity. Therefore, cell cycle phase marker detection can indicate malignancy in early melanocytic lesions and accelerated cell cycle progression during vertical melanoma growth.     

Pharmacological and computational analysis of alpha-subunit preferential GABA(A) positive allosteric modulators on the rat septo-hippocampal activity

Clinically most active anxiolytic drugs are positive allosteric modulators (PAMs) of GABA(A) receptors, represented by benzodiazepine compounds. Due to their non-selective profile, however, they potently modulate several sup-type specific GABA(A) receptors, contributing to their broad-range side effects. Based on observations in genetically altered mice, however, it has been proposed that anxiolytic action of benzodiazepines is predominantly mediated by GABA(A) alpha2/3 subunit-containing receptors. In the present study we analyzed the actions of the preferential GABA(A) alpha1 and alpha2/3 PAMs, zolpidem and L-838417, respectively on hippocampal EEG and medial septum neuronal activity in anesthetized rats. In parallel, a computational model was constructed to model pharmacological actions of these compounds on the septo-hippocampal circuitry. The present results demonstrated that zolpidem inhibited theta oscillation both in the hippocampus and septum, and profoundly inhibited firing activity of septal neurons. L-838417 also inhibited hippocampal and septal theta oscillation, however, it did not significantly alter firing rate activity of septal neurons. Our computational model showed that cessation of periodic firing of hippocampo-septal neurons, representing absence of hippocampal theta activity, disrupted oscillation of septal units, without altering their overall firing activity, similar to changes observed in our in vivo experiments following administration of L-838417. Understanding the correlation between changes in septo-hippocampal activity and actions of selective modulators of GABA(A) subtype receptor modulators would further advance design of anxiolytic drugs.     

The Representation of Suicide on the Internet: Implications for Clinicians

Background

Suicide is one of the major causes of death in the world, leading to approximately 1 million deaths per year. While much of what is said about suicide and its causes is still taboo in most contemporary societies and cultures, internet websites and discussion forums have become an important and controversial source of information on the subject. A great deal of ambivalence is discernible as to whether online communication about suicide primarily should be seen as an opportunity or a serious threat.

Objective

To investigate how the subject of suicide is represented on the Internet, based on hits generated by the search engine Google.

Methods

In an exploratory design, Google search results on the target word “suicide”, for the years 2005, 2009, and 2012 respectively, were systematically analyzed and compared.

Results

The study shows that web pages of institutional origin on the subject predominate, that the content provided by these institutions concerns primarily research and prevention, and that the form of communication used by these senders is almost exclusively monological. However, besides these institutional pages there are a substantial number of private senders and pages, often anti-medical and against treatment of depression and other mental problems, characterized by dialogue, confessions and narratives, and to a higher degree, an alternative pro-suicide stance.

Conclusions

To counteract the influence of anti-medical and pro-suicide information, the role of the Internet should be discussed with the patient in clinical practice. Dialogical and confessional communications provide an opportunity for the clinician to gain a deeper perspective into perceptions of patients, regarding both their afflictions and the role of medical treatment in their lives.     

Internet pathways in suicidality: a review of the evidence

The general aim of this study was to review the scientific literature concerning the Internet and suicidality and to examine the different pathways by which suicidal risks and prevention efforts are facilitated through the Internet. An online literature search was conducted using the MEDLINE and Google Scholar databases. The main themes that were investigated included pathological Internet use and suicidality, pro-suicide websites, suicide pacts on the Internet, and suicide prevention via the Internet. Articles were screened based on the titles and abstracts reporting on the themes of interest. Thereafter, articles were selected based on scientific relevance of the study, and included for full text assessment. The results illustrated that specific Internet pathways increased the risk for suicidal behaviours, particularly in adolescents and young people. Several studies found significant correlations between pathological Internet use and suicidal ideation and non-suicidal self-injury. Pro-suicide websites and online suicide pacts were observed as high-risk factors for facilitating suicidal behaviours, particularly among isolated and susceptible individuals. Conversely, the evidence also showed that the Internet could be an effective tool for suicide prevention, especially for socially-isolated and vulnerable individuals, who might otherwise be unreachable. It is this paradox that accentuates the need for further research in this field.     

Subcritical crack growth behavior and life data analysis of two types of dental Y-TZP ceramics

Objectives

The aim of this study was to evaluate the mechanical properties and the subcritical crack growth behavior of a presintered dental Y-TZP (Kavo Everest ZS) and a hot isostatic pressed Y-TZP (Kavo Everest ZH) and to perform life data analysis.

Methods

For each material 150 bending bars were produced. The initial fracture strength was determined in a four-point bending test. The subcritical crack growth parameters n and A were determined in a dynamic fatigue method at four decreasing loading rates from 110 MPa/s to 0.11 MPa/s in distilled water at 38 °C. For each loading rate Weibull statistics were performed and the Weibull moduli m and characteristic strengths σ₀ were calculated. Using these data, strength-fracture probability-life time (SPT) predictions were derived for 1 day, 1 year, 5 years and 10 years, based on a static crack growth mechanism.

Results

The “hipped” Y-TZP ceramic exhibited a higher initial strength (σ_c = 1618.18), characteristic strength (σ₀ = 837.15) and fracture toughness (K_IC = 4.52 MPa/m^1/2) than the pre-sintered ceramic (σ_c = 1431, σ₀ = 745.46 and K_IC = 3.17 MPa/m^1/2, respectively). Fatigue parameters, n and A, were 28.5 and 7.97 × 10⁻²⁴ for Everest ZH and 30.15 and 5.47 × 10⁻²⁰ for Everest ZS. The predicted fracture stress at 5% failure probability for a lifetime of 10 years was 259.34 MPa for Everest ZH and 263.2 MPa for Everest ZS.

Conclusions

Although the “hipped” Y-TZP showed favorable initial mechanical properties, no significant difference could be found in the susceptibility of both ceramics to subcritical crack growth and their long-term strength.     

Comparison of electrospun and extruded Soluplus®-based solid dosage forms of improved dissolution

Electrospinning (ES) and extrusion of a poorly water-soluble active pharmaceutical ingredient were used to improve its dissolution, which is a major challenge in the field of pharmaceutical technology. Spironolactone was applied as model drug and recently developed polyvinyl caprolactame-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus?) was used as carrier matrix and solubilizer. ES of the polymer matrix from ethanol solution was optimized at first without spironolactone and then the cosolution of the drug and the carrier was used for forming electrospun fibers. It resulted in real solid solution due to its very efficient amorphization effect. On the contrary, a low amount of crystalline spironolactone appeared in the extrudates according to Raman microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). Raman microspectrometry had the lowest detection limit of spironolactone crystals compared with XRD and differential scanning calorimetry. Both ES and extrusion techniques resulted in significantly improved dissolution. Electrospun ultrafine fibers increased the dissolution more effectively, owing to the formed solid solution and huge surface. The developed continuous technologies demonstrate great potential to tackle the challenge of inadequate dissolution of poorly water-soluble drugs in several cases.     

Diagnosis and successful management of calciphylaxis in a pancreas-kidney transplant patient

Nephrol Dial Transplant 2005 20: 1520–1521