4,106 research outputs found
Prognostic Markers in Pancreatic Cancer: the tumor and its environment
Incidence
Pancreatic cancer is not one of the most common types of cancer; however it is
most certainly one of the most devastating types, ranking fourth in the list of cancer
related deaths with a 5-year survival of only 6%. In 2010 there were an estimated
43.140 new cases whereas 36.800 patients were expected to die from this
disease in the United States. Worldwide, the expected numbers were 278.684
new cases and 266.669 deaths. In the Netherlands 2481 patients died of pancreatic
cancer in 2010. Interestingly, whereas for most cancers, death rates have
decreased over the years, those of pancreatic cancer have remained relatively
stable.
Pathogenesis
In order to effectively diagnose, prevent and treat pancreatic cancer, a detailed
understanding of the molecular biology of this disease is required. Like many
other cancers, pancreatic cancer results from the accumulation of genetic alterations.
It originates in the ductal epithelium and evolves from non-invasive precursor
lesions of which pancreatic intraepithelial neoplasias (PanINs) are the
best characterized. The progression from minimally dysplastic epithelium (PanIN
grade 1) to more severe dysplasia (PanIN grades 2 and 3) and finally to invasive
carcinoma is paralleled by the successive accumulation of genetic alterations of
which some appear earlier than others (figure 1).
A brief overview of the molecular mechanisms underlying the biology of pancreatic
cancer is given in chapter 2
The neurobiology of circadian rhythms
Purpose of review
There is growing awareness of the importance of circadian rhythmicity in various research fields. Exciting developments are ongoing in the field of circadian neurobiology linked to sleep, food intake, and memory. With the current knowledge of critical ‘clock genes’ (genes found to be involved in the generation of circadian rhythms) and novel techniques for imaging cyclic events in brain and peripheral tissue, this field of research is rapidly expanding. We reviewed only some of the highlights of the past year, and placed these findings into a mutual circadian perspective.
Recent findings
Recent findings on the organization of the circadian clock systems are addressed, ranging from the retina to the suprachiasmatic nucleus and peripheral organs. Novel developments in sleep, food intake, and memory research linked to circadian aspects are discussed.
Summary
The neurobiology of circadian rhythms is pivotal to the orchestration of the temporal organization of an individual’s physiology and behavior. Endogenous circadian timing systems underlie coupling and uncoupling mechanisms of many neuronal and physiological processes, the latter possibly inducing health risks to the organism. The integration of sleep, food intake and memory in a circadian setting has clear potential as a systems neurobiology line of research.
Impact and application of electron shuttles on the redox (bio)transformation of contaminants : a review
During the last two decades, extensive research has explored the catalytic effects of different organic molecules with redox mediating properties on the anaerobic (bio)transformation of a wide variety of organic and inorganic compounds. The accumulated evidence points at a major role of electron shuttles in the redox conversion of several distinct contaminants, both by chemical and biological mechanisms. Many microorganisms are capable of reducing redox mediators linked to the anaerobic oxidation of organic and inorganic substrates. Electron shuttles can also be chemically reduced by electron donors commonly found in anaerobic environments (e.g. sulfide and ferrous iron). Reduced electron shuttles can transfer electrons to several distinct electron-withdrawing compounds, such as azo dyes, polyhalogenated compounds, nitroaromatics and oxidized metalloids, among others. Moreover, reduced molecules with redox properties can support the microbial reduction of electron acceptors, such as nitrate, arsenate and perchlorate. The aim of this review paper is to summarize the results of reductive (bio)transformation processes catalyzed by electron shuttles and to indicate which aspects should be further investigated to enhance the applicability of redox mediators on the (bio)transformation of contaminants.F.P. van der Zee thanks the Portuguese Fundaicao para a Ciencia e a Tecnologia for financial support (Grant SFRH/BPD/39086/2007). F. J. Cervantes greatly acknowledges a grant from Council of Science and Technology of Mexico (Grant SEP-CONACYT-C02-55045)
Discontinuities without discontinuity: The Weakly-enforced Slip Method
Tectonic faults are commonly modelled as Volterra or Somigliana dislocations
in an elastic medium. Various solution methods exist for this problem. However,
the methods used in practice are often limiting, motivated by reasons of
computational efficiency rather than geophysical accuracy. A typical
geophysical application involves inverse problems for which many different
fault configurations need to be examined, each adding to the computational
load. In practice, this precludes conventional finite-element methods, which
suffer a large computational overhead on account of geometric changes. This
paper presents a new non-conforming finite-element method based on weak
imposition of the displacement discontinuity. The weak imposition of the
discontinuity enables the application of approximation spaces that are
independent of the dislocation geometry, thus enabling optimal reuse of
computational components. Such reuse of computational components renders
finite-element modeling a viable option for inverse problems in geophysical
applications. A detailed analysis of the approximation properties of the new
formulation is provided. The analysis is supported by numerical experiments in
2D and 3D.Comment: Submitted for publication in CMAM
Parent-reported problems in children with Cerebral Visual Impairment:Improving the discriminative ability from ADHD and dyslexia using screening inventories
Daily problems of children with Cerebral Visual Impairment (CVI) are often misinterpreted as symptoms of behavioural disorders or learning disabilities instead of higher order visual function (HOVF) deficits. It is difficult to differentiate between various paediatric clinical groups based on daily manifestations. We used two CVI inventories (V-CVI-I, HVFQI) and an ADHD questionnaire (AVL) to compare parent-reported visual and behavioural problems of children with CVI, ADHD, dyslexia and neurotypical children (Age 6–15, Verbal Intelligence > 70). Our results show a higher percentage of parent-reported visual problems in children with CVI compared to all other groups, which was not affected by their visual acuity levels. On most HOVF categories, a higher percentage of parent-reported visual problems was also found in children with ADHD or dyslexia compared to neurotypical children. Children with ADHD had significantly more parent-reported behavioural problems, but more behavioural problems were reported by the parents of children with CVI compared to neurotypical children as well. Our findings complicate using the existing inventories for initial screening and referral of children with potential CVI. We propose a shortened screening list to improve the potential differentiation between CVI and ADHD or dyslexia based on parent-reported visual problems in everyday life.</p
Whole body hyperthermia : the development of and experience with a clinical method
Whole body hyperthermia is one of the methods available for the treatment of
malignant turrours with heat. At the Rotterdam Radio-Therapeutic Institute this
method was investigated in 27 patients in a period of 3 1/2 years.
This thesis describes the results of this investigation.
The final conclusions from this study are:
the technique used for induction of WBHT is clinically useful and its efficiency
is comparable to the efficiencies mentioned by other authors Who
use a technique of transcutaneous energy input;
- WBHT at 41.8°C for 2 hours is effective, but has to be canbined with either
radiotherapy or cherrotherapy to obtain a valuable effect for the patient;
In sane cases the treatment may unexpectedly induce severe toxicity. Therefore
research should continue with regard to better alternatives such as
local hyperthennia and/or a safer method of WBHI'-induction
Способ профилактики и лечения послеоперационного гипотиреоза путем аутотрансплантации ткани щитовидной железы
Мета роботи - розробка ефективного способу хірургічного лікування й профілактики післяопераційного гіпотиреозу. Запропоновано спосіб профілактики та лікування післяопераційного гіпотиреозу методом аутотрансплантації щитоподібної залози. Наведені результати демонструють простоту, доступність і безпеку цього методу. Результати та обговорення. Ступінь гормональної компенсації після тиреоїдєктомії з аутотрансплантацією тиреоїдної тканини залежить від загальної маси аутографа, ваги пацієнта. Лікування післяопераційного гіпотиреозу методом аутотрансплантації оксігенованої тиреоїдної тканини щитоподібної залози є ефективним, простим, легким у виконанні, економічно доступним та доцільним.The aim - is to develop an affective method of surgical treatment of a postoperation hypothyroidism. Material and methods. The method of prophylaxis and treatment of a hypothyroidism by autotransplantation of a thyroid tissue worked out. For correction of postsurgical hypothyroidism the autotransplantation of oxygenated thyroid gland was performed with the following clinical-laboratory dynamics. Good results after autotransplantation of a thyroid tissue demonstrate the the simplicity,availability,safety and cheapness of this method of prophylaxis and treatment of a postoperation hypothyroidism. Completeness of hormonal compensation after thyroidectomy with autotransplantation of a thyroid tissue depends on weight of autografts, body weight of patient. Treatment of postoperation hypothyroidism by autotransplantation of a thyroid tissue is effective, simple, easy implemented and cost effective
Tres nuevas especies de killis (Cyprinodontiformes: Nothobranchiidae) de Guinea Ecuatorial
Two new Mesoaphyosemion species and one new species of the ’Aphyosemion’ herzogi group are described from the inland of Equatorial Guinea. The results of mtDNA analyses of most of the known phenotypes of the genus Mesoaphyosemion and the ‘Aphyosemion’ herzogi species group, respectively, are presented. Both new Mesoaphyosemion species have dark blotches on the posterior flanks and resemble M. maculatum from Gabon, yet they are not closely related to that species. Although the two new species occur in very close proximity, DNA results suggest no close relationship. The ‘Aphyosemion’ herzogi species group has a similar distribution as the genus Mesoaphyosemion, but with its northern boundary in southern Cameroon. Based on mtDNA the new ‘Aphyosemion’ from the Mitemele drainage in south west Equatorial Guinea is basal species to the remaining species group. It is distinguished from the two described congeners, ‘A.’ bochtleri and ‘A.’ herzogi by a diagnostic combination of colouration characters. Unpaired fins and flanks have a green background and caudal peduncle is often yellow to golden with dark red irregular dark red bars. The genetic dataindicate that the species group contains several additional, genetically and by colour pattern well separated, potentiallyundescribedspecies.
urn:lsid:zoobank.org:pub:2752DAEA-BEFE-4D6D-8D5C-FB3F0D265A4DSe describen para la parte continental de Guinea Ecuatorial dos nuevas especies de Mesoaphyosemion y una nueva especie del grupo de especies ‘Aphyosemion’ herzogi. También, se presentan los resultados de los análisis de DNAmt de casi todos los fenotipos conocidos del género Mesoaphyosemion y del grupo de especies ‘Aphyosemion’ herzogi. Ambas nuevas especies de Mesoaphyosemion tienen manchas oscuras en los flancos posteriores y se parecen a M. maculatum de Gabón, pero no están estrechamente relacionadas con esa especie. Aunque las dos nuevas especies son próximas, los resultados del ADN sugieren que no existe entre ellas una relación cercana. El grupo de especies ‘Aphyosemion’ herzogi tiene una distribución similar a la de Mesoaphyosemion, pero con su límite norte en el sur de Camerún. Basado en ADNmt, el nuevo ‘Aphyosemion’ de la cuenca del río Mitemele, en el suroeste de la parte continental de Guinea Ecuatorial, es una especie basal al resto de las especies estudiadas. Se distingue de los dos congéneres descritos, ‘A.’ bochtleri y ‘A.’ herzogi por una combinación de caracteres diagnósticos de la coloración. Las aletas impares y los flancostienen un fondo verde y el pedúnculo caudal suele ser de color amarillo a dorado con barras rojo oscuro irregulares. Los datos genéticosindicanque el grupo de especies contiene varias especies más, que están genéticamente y por patrón de coloración bien delimitadas, y que no han sido formalmente descritas
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