Sol-gel synthesis of nano-scale, end-member albite feldspar (NaAlSi3O8)

Feldspars are the most abundant minerals in the Earth's crust, and are also important constituents of many lunar rocks and some stony meteorites. Albite (NaAlSi₃O₈) makes up the sodium corner of the feldspar ternary diagram (KAlSi₃O₈ - NaAlSi₃O₈ - CaAl₂Si₂O₈) and connects the alkali-feldspar and plagioclase binary joins. Synthesis of albite, however, has long been a problem, even at high temperatures and even at high pressures when dry. In fact, most successful syntheses require the combination of high-pressure, high-temperature, and hydrothermal environments. This paper presents a sol-gel method of albite synthesis that requires hydrothermal processing followed by high-temperature recrystallization, but no high-pressure environments. This has the advantage of allowing synthesis of relatively large amounts of material and controlled elemental substitutions.

[Preclinical models in head and neck tumors : Evaluation of cellular and molecular resistance mechanisms in the tumor microenvironment]

Because head and neck squamous cell carcinomas (HNSCC) are characterized by a distinct intertumorigenic and intratumorigenic heterogeneity, they often show substantial differences in the response to established therapy strategies. At present, a multitude of biologics and new pharmacological compounds for targeted therapies are available that allow more efficient and less toxic treatment. There is increasing pressure to establish predictive assays not only for ex ante analysis of the individual patient response to combined chemoradiotherapy and targeted therapies but also for investigation of the efficacy of new drugs. In this respect it is essential to maintain the pathophysiological tissue composition as it is known that paracrine tumor-stroma cell interactions may influence tumor reactivity to treatment. More complex models for individualized sensitivity testing have recently been described and the results are promising to pave the way for personalized cancer therapy. This review article focuses on different systems for maintaining the tumor microenvironment and hence the individual cellular composition, such as 3D organotypic models, organotypic multicellular spheroids, patient-derived xenografts and ex vivo tissue cultures and discusses the advantages and disadvantages in terms of translation into clinical application.

An open-label phase II study of sorafenib and dacarbazine as first-line therapy in patients with advanced melanoma

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Background: Sorafenib (SOR) exerts anti-tumor and anti-angiogenic effects via inhibition of VEGFR-1,-2,-3, PDGFR-a, -β and Raf. In a phase I, study SOR + dacarbazine (DTIC) as first-line therapy for advanced melanoma patients (pts) was well-tolerated and had activity. Methods: In this multicenter, phase II, open-label, uncontrolled, 2-stage study, eligibility criteria included: measurable disease by RECIST, ECOG performance status 0 or 1, no prior chemotherapy. Prior immunotherapy was allowed. Planned sample size was 82 pts based on a Simon 2-stage optimal design. Pts were treated with oral SOR 400 mg bid daily combined with repeated 21-day cycles of iv DTIC 1,000 mg/m2 given on day 1 of each cycle until occurrence of progressive disease or intolerable toxicity. The primary endpoint was overall tumor response rate using RECIST. Secondary endpoints included progression-free survival (PFS), overall survival (OS), safety and toxicity. Results: 30 and 53 pts were treated in Stages I and II, respectively. Baseline characteristics were as follows: median age 56 yrs; 60% male, 34% ECOG 1, 80% AJCC Stage IV M1c; 31% elevated LDH. Eight (10%) pts had partial responses, 34 (41%) had stable disease, 32 (39%) had progressive disease and 9 (11%) were not evaluable. The median PFS was 14 wks (95% CI 12, 19; 28% censored). PFS rates at 3 & 6 mos were 56% (45%, 67%; 13% censored) and 33% (22%, 45%; 24% censored), respectively. Median OS was 41 wks (28, 59, 63% censored). Grade 3/4 drug-related adverse events included: neutrophils 33%, platelets 22%, hand-foot skin reaction 8%, fatigue 7% and abdominal pain 6%. 1 patient had febrile neutropenia. To correlate treatment response with mutational status, melanoma samples from 20 pts were analyzed for mutations in B-RAF (exon 15) and PI3Kinase (exons 9 & 20). 3 of 20 samples had V600E mutations in B- RAF; no PI3Kinase alterations were detected. Conclusions: Addition of SOR to DTIC was well-tolerated and resulted in encouraging PFS and OS rates in this poor prognostic cohort of patients. The data are promising as compared with published results of DTIC alone in metastatic melanoma (RR 7.5%, PFS 6 wks; Bedikian et al. 2006). A recently completed randomized Phase II trial will provide additional information on the efficacy of this combination regimen.

[Table: see text]

Comparison of p16INK4a expression with p53 alterations in head and neck cancer by tissue microarray analysis

We investigated whether there is a relationship between loss of p16(INK4a) protein expression and p53 alterations in head and neck squamous cell carcinomas (HNSCCs). For this purpose, immunohistochemistry was performed on tissue microarrays of 664 tumours; this represents the largest HNSCC cohort studied for molecular biomarkers. Loss of p16(INK4a) protein expression was associated with aberrant p53 expression (negative or overexpressed) in the total cohort, and with TP53 mutations in 200 tumours analysed (p < 0.0001 each). Both loss of p16(INK4a) expression and p53 alterations differed significantly across both tumour sites and stages, being more prevalent in the hypopharynx than in the other tumour sites and in advanced tumour stages. As a possible link between p53 status and p16(INK4a) loss, we found that increased DNA methyltransferase 1 protein levels occurred preferentially in tumours with aberrant p53 (p = 0.001) and negative p16(INK4a) expression (p = 0.0004). In the total cohort, there was a borderline significant difference in patient survival across three p16(INK4a) expression levels (negative, positive, high), with loss of p16(INK4a) expression showing shortest survival. It is suggested that loss of p16(INK4a) expression and p53 alterations should be viewed as related events involved in the early carcinogenic process.

Detailed gene expression analysis but not microsatellite marker analysis of 9p21 reveals differential defects in the INK4a gene locus in the majority of head and neck cancers

The INK4a gene locus on chromosome 9p21 encodes two proteins, p16(INK4a) and p14(ARF), which influence cell cycle control regulated by pRb and p53. The objective of this study was to use different methods for the analysis of the incidence of changes at the INK4a locus in head and neck cancer (HNSCC). Primary tumours were analysed for allelic imbalances (AI) with microsatellite markers for chromosome 9, by immunohistochemistry (IHC) and IHC with enhanced sensitivity by tyramide signal amplification (TSA-IHC), and by RT-PCR. No homozygous deletions at 9p21 were detected. AI at 9p21, which was found in approximately 60% of the tumours, completely failed to indicate the functional inactivation of the two INK4a gene products. Immunostaining of normal squamous epithelia revealed very low levels of p16(INK4a), whereas p14(ARF) was readily detectable. In 160 tumours, IHC suggested a loss of p16(INK4a) expression in 90%. However, by TSA-IHC, only 53.7% showed loss of p16(INK4a) expression, and this was consistent with the RT-PCR analyses. In 100 tumours analysed for both proteins, selective loss of p16(INK4a) occurred in 37%; loss of p14(ARF) was found in only 15%, and selective loss in only 4%; 11% of the tumours had lost both proteins. We conclude that only IHC with high sensitivity and the combined expression analysis of mRNAs and proteins is suitable for studying the role of INK4a in HNSCC. The INK4a gene expression defects are frequent but not universal and primarily affect p16(INK4a). Their clinical impact is still not clear.

[Radiation exposure of teeth and temporomandibular joints by radiography]

According to a report by Poretti (1975) 21,4% of all medical diagnostic radiographs in Switzerland are dental. In order to determine the associated radiation doses to patients, phantom measurements of skin and gonad exposures were made utilizing modern dental x-ray equipment and techniques. Following procedures in accordance with federal safety regulations it was not possible to measure dose values at the gonad level by single dental or temporomandibular radiographs, even by the most sensitive measuring device. 50 cumulative exposures without lead apron resulted in a range of gonad doses from 3.1 to 199 microR for dental and temporomandibular joint x-rays. Results of skin surface doses ranged from 38 to 289 mR for single dental film exposure and from 64 to 494 mR for single TMJ exposures. Consistent use of parallel technique with long cone equipment, small diaphragms, high kilovoltage and use of the lead apron guarantee great safety against radiation hazard in dental radiography.