152 resultados para Classification of zeolites
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Lung cancer is characterized by the highest incidence of solid tumor-related brain metastases, which are reported with a growing incidence during the last decade. Prognostic assessment may help to identify subgroups of patients that could benefit from more aggressive therapy of metastatic disease, in particular when central nervous system is involved. The recent sub-classification of non-small cell lung cancer (NSCLC) into molecularly-defined "oncogene-addicted" tumors, the emergence of effective targeted treatments in molecularly defined patient subsets, global improvement of advanced NSCLC survival as well as the availability of refined new radiotherapy techniques are likely to impact on outcomes of patients with brain dissemination. The present review focuses on key evidence and research strategies for systemic treatment of patients with central nervous system involvement in non-small cell lung cancer.
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Constitutive activation of the nuclear factor-KB (NF-KB) transcriptional pathway is the main characteristic of the activated B-cell-like (ABC) subtype of diffuse large B- cell lymphoma (DLBCL). This has been attributed to oncogenic mutations in the CARMA1, CD79A/B, MyD88 or RNF31 signaling proteins, which control NF-kB activation at different levels. Since several of these mutations lead to a state that mimics chronically antigen receptor-stimulated B-cells, and since the antigen receptor also triggers other transcription pathways, these might be important in ABC DLBCL malignancy too. In this study we analyzed whether abnormal expression and activity of members of the AP-1 transcription factor family could contribute to the pathogenesis of ABC DLBCL. Here, we identified activation of Jun as well as ATF members of the dimeric AP-1 transcription factor family, as a hallmark of ABC but not of germinal center B- cell-like (GCB) DLBCL cell lines. ABC DLBCL cell lines harbored an upregulated expression of c-Jun, JunB, JunD and ATF3 proteins. We could show that the upregulation of c-Jun, JunB and ATF3 was dependent on constitutive BCR and MyD88 signaling. Since AP-1 transcription factors need to dimerize to be active, Jun binding partners were investigated and we could demonstrate the presence of several ATF/Jun heterodimers (including c-Jun/ATF2, c-Jun/ATF3, c-Jun/ATF7, JunB/ATF2, JunB/ATF3, JunB/ATF7, JunD/ATF2, JunD/ATF3 and JunD/ATF7 heterodimers). The disruption of ATF/Jun heterodimers by A-Fos, a dominant negative form of Jun members, was toxic to ABC but not to GCB DLBCL cell lines. Finally, ATF3 immunohistochemistry on DLBCL patient samples revealed that samples classified as non-GCB had more intense and preferentially nuclear staining of ATF3, which could be of diagnostic relevance since the histological classification of the ABC and GCB DLBCL subtypes is difficult in clinical practice. In conclusion, we could show that ABC DLBCL are not only addicted to NF-KB signaling, but also to signaling by some members of the AP-1 transcription factor family. Thus, the AP-1 pathway might be a promising therapeutic target for the treatment of ABC DLBCL. Additionally, monitoring ATF3 levels could improve the diagnosis of ABC DLBCL by IHC. -- L'activation constitutive du facteur de transcription NF-KB est l'une des caractéristiques principales des lymphomes B du type ABC-DLBCL. Cette addiction est dépendante de mutations oncogéniques de CARMA1, CD79A/B, MyD88 et RNF31 qui contrôlent NF-KB à différents niveaux. Etant donné que la plupart de ces mutations mène à un état d'activation chronique du récepteur des cellules B (BCR) et que le BCR active d'autres voies de signalisation, d'autres facteurs de transcription pourraient être impliqués dans la lymphomagénèse des ABC-DLBCL. Dans cette étude, nous nous sommes demandé si les membres de la famille du facteur de transcription AP-1 contribuaient à la pathogénèse de ce type de lymphome. Dans des lignées cellulaires de lymphomes du type ABC-DLBCL en comparaison avec le type GCB-DLBCL, nous avons pu identifier une activation anormale de plusieurs membres de la famille Jun et ATF, deux sous-familles du facteur de transcription AP-1. Les lignées cellulaires dérivées de lymphomes du type ABC-DLBCL surexpriment les facteurs de transcription c-Jun, JunB, JunD et ATF3. Leur surexpression dépend de l'activation constitutive de la voie du BCR et de MyD88. Etant donné qu'AP-1 requiert la formation de dimères pour être actif, nous nous sommes intéressés aux partenaires d'interactions de c-Jun, JunB et JunD et avons pu montrer la formation de plusieurs hétérodimères Jun/ATF (incluant les hétérodimères c-Jun/ATF2, c-Jun/ATF3, c-Jun/ATF7, JunB/ATF2, JunB/ATF3, JunB/ATF7, JunD/ATF2, JunD/ATF3 et JunD/ATF7). Lorsque l'on empêche la formation de ces hétérodimères avec A-Fos, un dominant négatif des membres Jun, la survie des lignées cellulaires du type ABC-DLBCL est diminuée, tandis que les lignées cellulaires GCB-DLBCL ne sont pas affectées. Pour finir, des immunohistochimies (IHC) pour ATF3 sur des échantillons de patients classifiés comme GCB et non-GCB ont pu montrer une coloration d'ATF3 nucléaire et beaucoup plus intense que les échantillons du type GCB. Ainsi, ATF3 pourrait être potentiellement utile en clinique pour différencier le sous type non-GCB des GCB. En conclusion, nous avons pu montrer que les lymphomes du type ABC- DLBCL ne présentent pas uniquement une addiction à NF-KB, mais également de certains membres de la famille de facteur de transcription AP-1. Par conséquent, AP- 1 pourrait être une cible thérapeutique prometteuse pour le développement de futures stratégies. En outre, la détermination des niveaux d'ATF3 par IHC pourraient améliorer le diagnostic des patients du type ABC DLBCL.
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PURPOSE: To analyze available evidence on the incidence of anatomical variations or disease of the maxillary sinuses as identified by cone beam computed tomography (CBCT) in dentistry. MATERIALS AND METHODS: A focused question was developed to search the electronic databases MEDLINE, EMBASE, the Cochrane Oral Health Group Trials Register, and CENTRAL and identify all relevant papers published between 1980 and January 19, 2013. Unpublished literature at ClinicalTrials.gov, in the National Research Register, and in the Pro-Quest Dissertation Abstracts and Thesis database was also included. Studies were included irrespective of language. These results were supplemented by hand and gray literature searches. RESULTS: Twenty-two studies were identified. Twenty were retrospective cohort studies, one was a prospective cohort study, and one was a case control study. The main indication for CBCT was dental implant treatment planning, and the majority of studies used a small field of view for imaging. The most common anatomical variations included increased thickness of the sinus membrane, the presence of sinus septa, and pneumatization. Reported sinus disease frequency varied widely, ranging from 14.3% to 82%. There was a wide range in the reported prevalence of mucosal thickening related to apical pathology, the degree of lumenal opacification, features of sinusitis, and the presence of retention cysts and polyps. More pathologic findings in the maxillary sinus were reported in men than in women, and the medial wall and sinus floor were most frequently affected. CONCLUSION: CBCT is used primarily to evaluate bony anatomy and to screen for overt pathology of the maxillary sinuses prior to dental implant treatment. Differences in the classification of mucosal findings are problematic in the consistent and valid assessment of health and disease of the maxillary sinus.
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Background: The Valais's cancer registry (RVsT) of the Observatoire valaisan de le santé (OVS) and the department of oncology of Valais's Hospital conducted a study on the epidemiology and pattern of care of colorectal cancer in Valais. Colorectal cancer is the third cause of death by cancer in Switzerland with about 1600 deaths per year. It is the third most frequent cancer for males and the second most frequent for females in Valais. The number of new colorectal cancer cases (average per year) increased between 1989 and 2009 for males as well as for females in Valais. The number of colorectal cancer death cases (average per year) slightly increased between 1989 and 2009 for males as well as for females in Valais. Age-standardized rates of incidence were stable for males and females in Valais and in Switzerland between 1989 and 2009, while age-standardized rates of mortality decreased for males and females in Valais and Switzerland. Results: 774 cases were recorded (59% males). Median age at diagnosis was 70 years old. Most of cancers were invasive (79%) and the main localization was the colon (71%). The most frequent mode of detection was a consultation for non emergency symptoms (75%), but almost 10% of patients consulted in emergency. 82% of patients were treated within 30 days from diagnosis. 90% of the patients were treated by surgery alone or with combined treatment. The first treatment was surgery, including endoscopic resection in 86% of the cases. The treatment was different according to the localization and the stage of the cancer. Survival rate was 95% at 30 days and 79% at one year. The survival was dependent on the stage and the age at diagnosis. Cox model shows an association between mortality and age (better survival for young people) and between mortality and stage (better survival for the lower stages). Methods: RVsT collects information on all cancer cases since 1989 for people registered in the communes of Valais. RVsT has an authorization to collect non anonymized data. All new incident cancers are coded according to the International Classification of Diseases for Oncology (ICD-O-3) and the stages are coded according to the TNM classification. We studied all cases of in situ and invasive colorectal cancers diagnosed between 2006 and 2009 and registered routinely at the RVsT. We checked for data completeness and if necessary sent questionnaires to avoid missing data. A distance of 15 cm has been chosen to delimitate the colon (sigmoid) and the rectal cancers. We made an active follow-up for vital status to have a valid survival analysis. We analyzed the characteristics of the tumors according to age, sex, localization and stage with stata 9 software. Kaplan-Meier curves were generated and Cox model were fitted to analyze survival. Conclusion: The characteristics of patients and tumors and the one year survival were similar to those observed in Switzerland and some European countries. Patterns of care were close to those recommended in guidelines. Routine data recorded in a cancer registry can be used, not only to provide general statistics, but also to help clinicians assess local practices.
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A precise classification and an optimal understanding of tibial plateau fractures are the basis of a conservative treatment or adequate surgery. The aim of this prospective study is to determine the contribution of 3D CT to the classification of fractures (comparison with standard X-rays) and as an aid to the surgeon in preoperative planning and surgical reconstruction. Between November 1994 and July 1996, 20 patients presenting 22 tibial plateau fractures were considered in this study. They all underwent surgical treatment. The fractures were classified according to the Müller AO classification. They were all investigated by means of standard X-rays (AP, profile, oblique) and the 3D CT. Analysis of the results has shown the superiority of 3D CT in the planning (easier and more acute), in the classification (more precise), and in the exact assessment of the lesions (quantity of fragments); thereby proving to be of undeniable value of the surgeon.
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Significant progress has been made in the molecular diagnostic subtyping of brain tumors, in particular gliomas. In contrast to the classical molecular markers in this field, p53 and epidermal growth factor receptor (EGFR) status, the clinical significance of which has remained controversial, at least three important molecular markers with clinical implications have now been identified: 1p/19q codeletion, O⁶-methylguanine methyltransferase (MGMT) promoter methylation and isocitrate dehydrogenase-1 (IDH1) mutations. All three are favorable prognostic markers. 1p/19q codeletion and IDH1 mutations are also useful to support and extend the histological classification of gliomas since they are strongly linked to oligodendroglial morphology and grade II/III gliomas, as opposed to glioblastoma, respectively. MGMT promoter methylation is the only potentially predictive marker, at least for alkylating agent chemotherapy in glioblastoma. Beyond these classical markers, the increasing repertoire of anti-angiogenic agents that are currently explored within registration trials for gliomas urgently calls for efforts to identify molecular markers that predict the benefit derived from these novel treatments, too.
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Dual-energy X-ray absorptiometry (DXA) is commonly used in the care of patients for diagnostic classification of osteoporosis, low bone mass (osteopenia), or normal bone density; assessment of fracture risk; and monitoring changes in bone density over time. The development of other technologies for the evaluation of skeletal health has been associated with uncertainties regarding their applications in clinical practice. Quantitative ultrasound (QUS), a technology for measuring properties of bone at peripheral skeletal sites, is more portable and less expensive than DXA, without the use of ionizing radiation. The proliferation of QUS devices that are technologically diverse, measuring and reporting variable bone parameters in different ways, examining different skeletal sites, and having differing levels of validating data for association with DXA-measured bone density and fracture risk, has created many challenges in applying QUS for use in clinical practice. The International Society for Clinical Densitometry (ISCD) 2007 Position Development Conference (PDC) addressed clinical applications of QUS for fracture risk assessment, diagnosis of osteoporosis, treatment initiation, monitoring of treatment, and quality assurance/quality control. The ISCD Official Positions on QUS resulting from this PDC, the rationale for their establishment, and recommendations for further study are presented here.
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BACKGROUND: Children and adolescents are at high risk of sustaining fractures during growth. Therefore, epidemiological assessment is crucial for fracture prevention. The AO Comprehensive Injury Automatic Classifier (AO COIAC) was used to evaluate epidemiological data of pediatric long bone fractures in a large cohort. METHODS: Data from children and adolescents with long bone fractures sustained between 2009 and 2011, treated at either of two tertiary pediatric surgery hospitals in Switzerland, were retrospectively collected. Fractures were classified according to the AO Pediatric Comprehensive Classification of Long Bone Fractures (PCCF). RESULTS: For a total of 2716 patients (60% boys), 2807 accidents with 2840 long bone fractures (59% radius/ulna; 21% humerus; 15% tibia/fibula; 5% femur) were documented. Children's mean age (SD) was 8.2 (4.0) years (6% infants; 26% preschool children; 40% school children; 28% adolescents). Adolescent boys sustained more fractures than girls (p < 0.001). The leading cause of fractures was falls (27%), followed by accidents occurring during leisure activities (25%), at home (14%), on playgrounds (11%), and traffic (11%) and school accidents (8%). There was boy predominance for all accident types except for playground and at home accidents. The distribution of accident types differed according to age classes (p < 0.001). Twenty-six percent of patients were classed as overweight or obese - higher than data published by the WHO for the corresponding ages - with a higher proportion of overweight and obese boys than in the Swiss population (p < 0.0001). CONCLUSION: Overall, differences in the fracture distribution were sex and age related. Overweight and obese patients seemed to be at increased risk of sustaining fractures. Our data give valuable input into future development of prevention strategies. The AO PCCF proved to be useful in epidemiological reporting and analysis of pediatric long bone fractures.
Complications of different ventilation strategies in endoscopic laryngeal surgery: a 10-year review.
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BACKGROUND: Spontaneous ventilation, mechanical controlled ventilation, apneic intermittent ventilation, and jet ventilation are commonly used during interventional suspension microlaryngoscopy. The aim of this study was to investigate specific complications of each technique, with special emphasis on transtracheal and transglottal jet ventilation. METHODS: The authors performed a retrospective single-institution analysis of a case series of 1,093 microlaryngoscopies performed in 661 patients between January 1994 and January 2004. Data were collected from two separate prospective databases. Feasibility and complications encountered with each technique of ventilation were analyzed as main outcome measures. RESULTS: During 1,093 suspension microlaryngoscopies, ventilation was supplied by mechanical controlled ventilation via small endotracheal tubes (n = 200), intermittent apneic ventilation (n = 159), transtracheal jet ventilation (n = 265), or transglottal jet ventilation (n = 469). Twenty-nine minor and 4 major complications occurred. Seventy-five percent of the patients with major events had an American Society of Anesthesiologists physical status classification of III. Five laryngospasms were observed with apneic intermittent ventilation. All other 24 complications (including 7 barotrauma) occurred during jet ventilation. Transtracheal jet ventilation was associated with a significantly higher complication rate than transglottal jet ventilation (P < 0.0001; odds ratio, 4.3 [95% confidence interval, 1.9-10.0]). All severe complications were related to barotraumas resulting from airway outflow obstruction during jet ventilation, most often laryngospasms. CONCLUSIONS: The use of a transtracheal cannula was the major independent risk factor for complications during jet ventilation for interventional microlaryngoscopy. The anesthetist's vigilance in clinically detecting and preventing outflow airway obstruction remains the best prevention of barotrauma during subglottic jet ventilation.
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Spatial data analysis mapping and visualization is of great importance in various fields: environment, pollution, natural hazards and risks, epidemiology, spatial econometrics, etc. A basic task of spatial mapping is to make predictions based on some empirical data (measurements). A number of state-of-the-art methods can be used for the task: deterministic interpolations, methods of geostatistics: the family of kriging estimators (Deutsch and Journel, 1997), machine learning algorithms such as artificial neural networks (ANN) of different architectures, hybrid ANN-geostatistics models (Kanevski and Maignan, 2004; Kanevski et al., 1996), etc. All the methods mentioned above can be used for solving the problem of spatial data mapping. Environmental empirical data are always contaminated/corrupted by noise, and often with noise of unknown nature. That's one of the reasons why deterministic models can be inconsistent, since they treat the measurements as values of some unknown function that should be interpolated. Kriging estimators treat the measurements as the realization of some spatial randomn process. To obtain the estimation with kriging one has to model the spatial structure of the data: spatial correlation function or (semi-)variogram. This task can be complicated if there is not sufficient number of measurements and variogram is sensitive to outliers and extremes. ANN is a powerful tool, but it also suffers from the number of reasons. of a special type ? multiplayer perceptrons ? are often used as a detrending tool in hybrid (ANN+geostatistics) models (Kanevski and Maignank, 2004). Therefore, development and adaptation of the method that would be nonlinear and robust to noise in measurements, would deal with the small empirical datasets and which has solid mathematical background is of great importance. The present paper deals with such model, based on Statistical Learning Theory (SLT) - Support Vector Regression. SLT is a general mathematical framework devoted to the problem of estimation of the dependencies from empirical data (Hastie et al, 2004; Vapnik, 1998). SLT models for classification - Support Vector Machines - have shown good results on different machine learning tasks. The results of SVM classification of spatial data are also promising (Kanevski et al, 2002). The properties of SVM for regression - Support Vector Regression (SVR) are less studied. First results of the application of SVR for spatial mapping of physical quantities were obtained by the authorsin for mapping of medium porosity (Kanevski et al, 1999), and for mapping of radioactively contaminated territories (Kanevski and Canu, 2000). The present paper is devoted to further understanding of the properties of SVR model for spatial data analysis and mapping. Detailed description of the SVR theory can be found in (Cristianini and Shawe-Taylor, 2000; Smola, 1996) and basic equations for the nonlinear modeling are given in section 2. Section 3 discusses the application of SVR for spatial data mapping on the real case study - soil pollution by Cs137 radionuclide. Section 4 discusses the properties of the modelapplied to noised data or data with outliers.
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Many people worldwide live with a disability, i.e. limitations in functioning. The prevalence is expected to increase due to demographic change and the growing importance of non-communicable disease and injury. To date, many epidemiological studies have used simple dichotomous measures of disability, even though the WHO's International Classification of Functioning, Disability, and Health (ICF) provides a multi-dimensional framework of functioning. We aimed to examine associations of socio-economic status (SES) and social integration in 3 core domains of functioning (impairment, pain, limitations in activity and participation) and perceived health. We conducted a secondary analysis of representative cross-sectional data of the Swiss Health Survey 2007 including 10,336 female and 8,424 male Swiss residents aged 15 or more. Guided by a theoretical ICF-based model, 4 mixed effects Poisson regressions were fitted in order to explain functioning and perceived health by indicators of SES and social integration. Analyses were stratified by age groups (15-30, 31-54, ≥55 years). In all age groups, SES and social integration were significantly associated with functional and perceived health. Among the functional domains, impairment and pain were closely related, and both were associated with limitations in activity and participation. SES, social integration and functioning were related to perceived health. We found pronounced social inequalities in functioning and perceived health, supporting our theoretical model. Social factors play a significant role in the experience of health, even in a wealthy country such as Switzerland. These findings await confirmation in other, particularly lower resourced settings.
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BACKGROUND: Mortality among HIV-infected persons is decreasing, and causes of death are changing. Classification of deaths is hampered because of low autopsy rates, frequent deaths outside of hospitals, and shortcomings of International Statistical Classification of Diseases and Related Health Problems (ICD-10) coding. METHODS: We studied mortality among Swiss HIV Cohort Study (SHCS) participants (1988-2010) and causes of death using the Coding Causes of Death in HIV (CoDe) protocol (2005-2009). Furthermore, we linked the SHCS data to the Swiss National Cohort (SNC) cause of death registry. RESULTS: AIDS-related mortality peaked in 1992 [11.0/100 person-years (PY)] and decreased to 0.144/100 PY (2006); non-AIDS-related mortality ranged between 1.74 (1993) and 0.776/100 PY (2006); mortality of unknown cause ranged between 2.33 and 0.206/100 PY. From 2005 to 2009, 459 of 9053 participants (5.1%) died. Underlying causes of deaths were: non-AIDS malignancies [total, 85 (19%) of 446 deceased persons with known hepatitis C virus (HCV) status; HCV-negative persons, 59 (24%); HCV-coinfected persons, 26 (13%)]; AIDS [73 (16%); 50 (21%); 23 (11%)]; liver failure [67 (15%); 12 (5%); 55 (27%)]; non-AIDS infections [42 (9%); 13 (5%); 29 (14%)]; substance use [31 (7%); 9 (4%); 22 (11%)]; suicide [28 (6%); 17 (7%), 11 (6%)]; myocardial infarction [28 (6%); 24 (10%), 4 (2%)]. Characteristics of deceased persons differed in 2005 vs. 2009: median age (45 vs. 49 years, respectively); median CD4 count (257 vs. 321 cells/μL, respectively); the percentage of individuals who were antiretroviral therapy-naïve (13 vs. 5%, respectively); the percentage of deaths that were AIDS-related (23 vs. 9%, respectively); and the percentage of deaths from non-AIDS-related malignancies (13 vs. 24%, respectively). Concordance in the classification of deaths was 72% between CoDe and ICD-10 coding in the SHCS; and 60% between the SHCS and the SNC registry. CONCLUSIONS: Mortality in HIV-positive persons decreased to 1.33/100 PY in 2010. Hepatitis B or C virus coinfections increased the risk of death. Between 2005 and 2009, 84% of deaths were non-AIDS-related. Causes of deaths varied according to data source and coding system.
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We present a method to automatically segment red blood cells (RBCs) visualized by digital holographic microscopy (DHM), which is based on the marker-controlled watershed algorithm. Quantitative phase images of RBCs can be obtained by using off-axis DHM along to provide some important information about each RBC, including size, shape, volume, hemoglobin content, etc. The most important process of segmentation based on marker-controlled watershed is to perform an accurate localization of internal and external markers. Here, we first obtain the binary image via Otsu algorithm. Then, we apply morphological operations to the binary image to get the internal markers. We then apply the distance transform algorithm combined with the watershed algorithm to generate external markers based on internal markers. Finally, combining the internal and external markers, we modify the original gradient image and apply the watershed algorithm. By appropriately identifying the internal and external markers, the problems of oversegmentation and undersegmentation are avoided. Furthermore, the internal and external parts of the RBCs phase image can also be segmented by using the marker-controlled watershed combined with our method, which can identify the internal and external markers appropriately. Our experimental results show that the proposed method achieves good performance in terms of segmenting RBCs and could thus be helpful when combined with an automated classification of RBCs.
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Background: Arundinarieae are a large tribe of temperate woody bamboos for which phylogenetics are poorly understood because of limited taxon sampling and lack of informative characters. Aims: This study assessed phylogenetic relationships, origins and classification of Arundinarieae. Methods: DNA sequences (plastid trnL-F; nuclear ITS) were used for parsimony and Bayesian inference including 41 woody bamboo taxa. Divergence dates were estimated using a relaxed Bayesian clock. Results: Arundinarieae were monophyletic but their molecular divergence was low compared to the tropical Bambuseae. Ancestors of the Arundinarieae lineage were estimated to have diverged from the other bamboos 23 (15-30) million years ago (Mya). However, the Arundinarieae radiation occurred 10 (6-16) Mya compared to 18 (11-25) Mya for the tropical Bambuseae. Some groups could be defined within Arundinarieae, but they do not correspond to recognised subtribes such as Arundinariinae or Shibataeinae. Conclusions: Arundinarieae are a relatively ancient bambusoid lineage that underwent a rapid radiation in the late Miocene. The radiation coincides with the continental collision of the Indo-Australian and Eurasian Plates. Arundinarieae are distributed primarily in East Asia and the Himalayas to northern Southeast Asia. It is unknown whether they were present in Asia long before their radiation, but we believe recent dispersal is a more likely scenario. Keywords: Arundinarieae; Bambuseae; internal transcribed spacer (ITS); molecular clock; phylogenetics; radiation; temperate bamboos; Thamnocalaminae; trnL-F
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Eight stomatitis papulosa (SP), four orf and two milker's nodes (MN) virus isolates were compared by restriction enzyme analysis. Considerable genetic heterogeneity was found not only between isolates belonging to the three different taxonomic groups but also between members of the same group. This heterogeneity precludes classification of parapoxviruses simply by comparison of their DNA cleavage patterns. Restriction maps were therefore prepared for 12 parapoxvirus DNAs. Fragments from defined regions of the genome were then selected and used as probes for cross-hybridizations to all other parapoxvirus DNAs. DNA fragments derived from an internal region of the genome hybridized strongly to all parapoxvirus isolates examined. In contrast, cross-hybridization of the end region of the DNA molecule was observed only between members of the same virus group. Molecular hybridization as a means of classifying parapoxvirus isolates is discussed.