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Increased Chance (increased + chance)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

Repair of a Large Wound of the Back, Post-Mohs Micrographical Excision, Using Chronic Skin Expansion

DERMATOLOGIC SURGERY, Issue 6 2003
Ron M. Shelton MD
Background. Large defects not otherwise closed primarily may be closed after chronic skin expansion. Objective. If chronic expansion were deemed indicated for the closure of a proposed defect expected to result from Mohs micrographic surgery, can it be performed before Mohs surgery, avoiding the increased chance of expander extrusion via the defect when done postoperatively? Methods. A team approach of a Mohs surgeon and a plastic surgeon coordinated scheduling an insertion of and staged infiltration of a tissue expander before Mohs surgical removal of a large basal cell carcinoma on the back of a young woman. The reconstruction after Mohs surgery was scheduled for the immediate postoperative period. Results. The Mohs surgery completed removed the carcinoma, and the expander was removed, enabling the surgeon to perform a side-to-side closure. Conclusion. Provided that there is not a great probability of the neoplasm extending significantly deeper or wider than expected and that the skin expander is placed so as not to disturb the plane of Mohs excision, this is a useful technique to close large Mohs defects. [source]

CALORIE RESTRICTION AND AGING: A LIFE-HISTORY ANALYSIS

EVOLUTION, Issue 3 2000
Daryl P. Shanley
Abstract., The disposable soma theory suggests that aging occurs because natural selection favors a strategy in which fewer resources are invested in somatic maintenance than are necessary for indefinite survival. However, laboratory rodents on calorie-restricted diets have extended life spans and retarded aging. One hypothesis is that this is an adaptive response involving a shift of resources during short periods of famine away from reproduction and toward increased somatic maintenance. The potential benefit is that the animal gains an increased chance of survival with a reduced intrinsic rate of senescence, thereby permitting reproductive value to be preserved for when the famine is over. We describe a mathematical life-history model of dynamic resource allocation that tests this idea. Senescence is modeled as a change in state that depends on the resources allocated to maintenance. Individuals are assumed to allocate the available resources to maximize the total number of descendants. The model shows that the evolutionary hypothesis is plausible and identifies two factors, both likely to exist, that favor this conclusion. These factors are that survival of juveniles is reduced during periods of famine and that the organism needs to pay an energetic "overhead" before any litter of offspring can be produced. If neither of these conditions holds, there is no evolutionary advantage to be gained from switching extra resources to maintenance. The model provides a basis to evaluate whether the life-extending effects of calorie-restriction might apply in other species, including humans. [source]

Reproductive assurance through self-fertilization does not vary with population size in the alien invasive plant Datura stramonium

OIKOS, Issue 8 2007
Mark van Kleunen
Autonomous self-fertilization is suggested to be associated with invasiveness in plants because it offers reproductive assurance when there is a shortage of suitable mates or pollinators. Given that shortages of mates and pollinators are a common cause of Allee effects in small plant populations, we predict that the benefits of self-fertilization in terms of reproductive assurance should be greatest in small populations. We tested this idea for the invasive herb Datura stramonium, a self-fertilizing species which is also cross-pollinated to some extent by insects (mainly hawkmoths and honeybees). During two consecutive years, we studied 20 and 55 populations, respectively, of different sizes. Untreated flowers of D. stramonium showed high levels of fruit and seed set in all populations studied. Although, fruit and seed set were generally reduced by about 90% in flowers in which self-fertilization was prevented through emasculation, this effect did not vary according to population size. By using a natural color (anthocyanin) dimorphism in 12 populations, we showed that the average outcrossing rate was low (1.3%) and that there was no relationship between outcrossing rate and population size. Pollen removal from flowers also did not vary according to population size, suggesting that the pollinator visitation rate is not lower in small populations. However, decreasing deviations of observed from expected fruit set with population size imply that small populations may have an increased chance of extinction due to demographic stochasticity. Overall, our results suggest that reproductive assurance through self-fertilization in invasive plants may be important for all stages of population establishment, and not just in the founder population. [source]

Silicon-augmented resistance of plants to herbivorous insects: a review

ANNALS OF APPLIED BIOLOGY, Issue 2 2009
O.L. Reynolds
Abstract Silicon (Si) is one of the most abundant elements in the earth's crust, although its essentiality in plant growth is not clearly established. However, the importance of Si as an element that is particularly beneficial for plants under a range of abiotic and biotic stresses is now beyond doubt. This paper reviews progress in exploring the benefits at two- and three-trophic levels and the underlying mechanism of Si in enhancing the resistance of host plants to herbivorous insects. Numerous studies have shown an enhanced resistance of plants to insect herbivores including folivores, borers, and phloem and xylem feeders. Silicon may act directly on insect herbivores leading to a reduction in insect performance and plant damage. Various indirect effects may also be caused, for example, by delaying herbivore establishment and thus an increased chance of exposure to natural enemies, adverse weather events or control measures that target exposed insects. A further indirect effect of Si may be to increase tolerance of plants to abiotic stresses, notably water stress, which can in turn lead to a reduction in insect numbers and plant damage. There are two mechanisms by which Si is likely to increase resistance to herbivore feeding. Increased physical resistance (constitutive), based on solid amorphous silica, has long been considered the major mechanism of Si-mediated defences of plants, although there is recent evidence for induced physical defence. Physical resistance involves reduced digestibility and/or increased hardness and abrasiveness of plant tissues because of silica deposition, mainly as opaline phytoliths, in various tissues, including epidermal silica cells. Further, there is now evidence that soluble Si is involved in induced chemical defences to insect herbivore attack through the enhanced production of defensive enzymes or possibly the enhanced release of plant volatiles. However, only two studies have tested for the effect of Si on an insect herbivore and third trophic level effects on the herbivore's predators and parasitoids. One study showed no effect of Si on natural enemies, but the methods used were not favourable for the detection of semiochemical-mediated effects. Work recently commenced in Australia is methodologically and conceptually more advanced and an effect of Si on the plants' ability to generate an induced response by acting at the third trophic level was observed. This paper provides the first overview of Si in insect herbivore resistance studies, and highlights novel, recent hypotheses and findings in this area of research. Finally, we make suggestions for future research efforts in the use of Si to enhance plant resistance to insect herbivores. [source]

Implementation of a short-stay programme after breast cancer surgery,

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 2 2010
M. de Kok
Background: Short-stay breast cancer surgery (24 h or day case) is not common practice in Europe. This before,after comparative study was carried out to test the feasibility of systematically implementing a care programme incorporating short-stay admission using strategies tailored to individual hospital needs, and to assess safety and facilitating factors. Methods: Patients with breast cancer from four Dutch hospitals participated. The intervention concerned the programme developed by the Maastricht University Medical Centre. This was implemented through local multidisciplinary meetings and educational outreach visits. Results: Of 421 eligible patients, 324 (77·0 per cent) gave consent to participate. The proportion of patients who had short-stay treatment increased from 45·3 per cent before to 82·2 per cent after implementation of the programme (P < 0·001). No increase was observed in the rate of complications, readmissions, reoperations or number of visits to the emergency department. Factors associated with an increased chance of short-stay treatment were: breast-conserving surgery, having children and being employed. Being aged over 64 years showed a trend towards a decreased chance. Conclusion: Introducing a care programme incorporating short stay following breast cancer surgery in four hospitals was feasible and safe. Copyright © 2010 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source]

Clinical characteristics and outcomes for a modern series of primary gliosarcoma patients

CANCER, Issue 5 2010
Seunggu J. Han BS
Abstract BACKGROUND: Primary gliosarcoma (PGS) is a rare central nervous system tumor with limited experience reported in the literature. In the current study, the authors present a modern series of confirmed PGS cases treated in the era of magnetic resonance imaging (MRI), after the accepted glioblastoma management of resection, radiation, and temozolomide. METHODS: Using a retrospective review, patients with confirmed PGS were identified (1996-2008). Cases were determined to be PGS by central pathology review using the 2007 World Health Organization criteria. Extensive chart review was performed to gather clinical and pathologic data on these cases. RESULTS: All but 1 patient had undergone a preoperative MRI, with 1 patient receiving a computed tomography scan due to a cardiac pacemaker. A total of 10 patients received radiotherapy with concurrent and adjuvant temozolomide chemotherapy, and 8 patients received radiotherapy alone or in combination with other chemotherapeutic agents. In 2 patients, the history of adjuvant treatment could not be confirmed. The overall median survival was 13.9 months (range, 2.2-22.9 months). Patients with gliosarcomas resembling meningioma were found to have a significantly prolonged median survival compared with patients harboring gliosarcoma resembling glioblastoma multiforme (16 months vs 9.6 months; P = .011). However, no difference in survival was noted between patients who received concurrent radiotherapy and temozolomide compared with those who did not (10.4 months vs 13.9 months; P = .946). CONCLUSIONS: The results of the current study support previous hypotheses that there are 2 distinct types of PGS. The type mimicking the appearance of a meningioma appears to carry a significantly more favorable prognosis, most likely due to an increased chance at achieving macroscopic total resection. Cancer 2010. © 2010 American Cancer Society. [source]