The current focus of cancer research is still based on biological

The current focus of cancer research is still based on biological capabilities such as molecular genetics and gene signaling, but these approaches ignore the mechanical nature of the invasion

process of cancer cells. This review will focus on how structural, biochemical and mechanical properties of extracellular matrices (ECMs), and adjacent cells regulate the invasiveness of cancer cells. In addition, it presents how cancer cells create their own microenvironment by restructuring of the ECM and by interaction with stromal cells, which then further contribute to the progression of cancer disease. Finally, this review will point out that mechanical properties are a critical determinant for the efficiency of cancer cell invasion and the progression of cancer which might affect the future development of new buy MK-2206 cancer treatments.”
“This paper is devoted to the analysis of the effectiveness of the use of arable land. This is an issue, which is important for national-level decision makers. The particular

calculations are carried out for Hungary, but similar analysis can be made for each country having several parts with different geographical conditions.\n\nIn general the this website structure of the use of arable land has been developed in an evolutionary manner in each country. This paper is devoted to the evaluation of the effectiveness of this structure. Some main crops must be included in the analysis such that the land used for their production is a high percentage in the total arable land of the country. From agricultural point of view the question to be

answered is whether or not the same level of supply is achievable with high probability on a smaller area. As the agriculture is affected by stochastic factors via the weather, no supply can be guaranteed up to 100 per cent. Thus each production structure provides the required supply only with a certain probability. One inequality corresponding to each crop must be satisfied at the same time with a prescribed probability. The main theoretical difficulty here is that the inequalities are not independent from one another from stochastic point of view as the yields of the crops are highly selleck chemical correlated. The problem is modeled by a chance constrained stochastic programming model such that the stochastic variables are on the left-hand side of the inequalities, while the right-hand sides are constants. Kataoka was the first in 1963 who solved a similar problem with a single inequality in the probabilistic constraint. The mathematical analysis of the present problem is using the results of Kataoka. This problem is solved numerically via discretization.\n\4 nNumerical results for the optimal structure of the production are presented for the case of Hungary. It is shown that a much higher probability, i.e.

Design: Cross-sectional survey Setting:

Data for

\n\nDesign: Cross-sectional survey.\n\nSetting:

Data for 405 healthy free-living elderly Quebecers aged between 68 and 82 years with no major health problems were examined.\n\nSubjects: Men and women in age groups of 68-72, 73-77, and 78-82 years, in 2 seasons, participating in the NuAge cohort. Measurements: serum 25(OH)D assessed by radioimmunoassay AZD4547 (RIA), weight, height, smoking status, disease status, education, perception of income, Physical Activity Scale for the Elderly (PASE) questionnaire, and vitamin D supplement consumption.\n\nResults: The prevalence of vitamin D deficiency (25(OH)D <37.5 nmol/L) was 12.6% and 5.7% for men in winter and summer, and 8.7% and 1.9% for women, respectively. Over 50% of the participants had 25(OH)D concentrations

<75 nmol/L. Correlates of vitamin D status by multiple regression analysis indicated that the vitamin D level in summer was 13.8 nmol/L higher for participants measured in winter and 17.2 nmol/L higher for those using supplements. Age, sex, body mass index, and physical activity were not associated with 25(OH)D concentration.\n\nConclusion: Prevalence of vitamin D deficiency is low in healthy elderly men and women, especially in summer, but over 50% of the participants had suboptimal vitamin D concentrations. Vitamin D supplement consumption increased 25(OH)D concentrations substantially, particularly in the winter ABT-737 cell line months, and should be encouraged.”
“Introduction: Apolipoprotein E4 (ApoE

epsilon 4) polymorphism is a known genetic risk factor for Alzheimer’s disease (AD). Objectives: To evaluate the role of ApoE epsilon 4 on white matter structural integrity in AD. Methods: Subjects were 32 patients with probable AD (ApoE epsilon 4-positive: n = 15) and 18 matched controls (ApoE epsilon 4-positive: n = 6). All subjects were right-handed, evaluated using standard scales and genotyped at the ApoE locus. Diffusion tensor imaging was performed with a 3-tesla MRI scanner and analyzed using the tract-based spatial statistics method. Results: AD patients had significantly lower fractional anisotropy (FA) in bilateral temporoparietal, limbic and selleck compound parahippocampal regions in comparison to healthy comparison subjects. ApoE epsilon 4 carriers among both AD and healthy comparison subjects showed lower FA in limbic and medial temporal regions. Conclusions: There is a modest association between ApoE epsilon 4 carrier status and reduction in white matter tract integrity at medial temporal and limbic regions in both healthy and AD subjects. Copyright (C) 2012 S. Karger AG, Basel”
“New methods are required to increase our understanding of pathologic processes in wild mammals. We developed a noninvasive held method to estimate the body temperature of wild living chimpanzees habituated to humans, based on statistically fitting temperature decline of feces after defecation.

A challenging approach is the use of stem cells to repair the hea

A challenging approach is the use of stem cells to repair the heart, in itself an inspiring thought. In the past 10 years, stem cells from different sources have been under intense investigation and, BKM120 as a result, a multitude of studies have been published on the identification, isolation, and characterization, of cardiovascular progenitor cells and repair in different animal models. However, relatively few cardiovascular

progenitor populations have been identified in human hearts, including, but not limited to, cardiosphere-derived cells , cKit+ human cardiac stem cells , Isl1+ cardiovascular progenitors , and, in our lab, cardiomyocyte progenitor cells (CMPCs) . Here, we aim to provide a comprehensive summary of the past findings and present challenges for future therapeutic potential of CMPCs.”
“Ventricular oversensing remains a significant problem in modern implantable cardioverter-defibrillator (ICD) systems. The role of manufacturer-related differences

in device-based signal processing on the one hand and sensing lead properties on the other Vactosertib inhibitor is largely unknown. This retrospective study aimed to evaluate and compare the incidence and mechanisms of ventricular oversensing in single- or dual-chamber ICD systems from Biotronik (BTK), Guidant (GDT), and Medtronic (MDT).\n\nIn 245 consecutive patients, device function, stored episodes, and lead parameters were evaluated at BMS-777607 in vivo implant and during 243 +/- 18 days of follow-up. Oversensing occurred in 3.3% of the patients [four T-wave oversensing (TWO), three R-wave double-sensing,

and one diaphragmatic myopotentials]. The incidence of ventricular oversensing was generally low if an ICD device and an ICD lead were from one identical manufacturer (BTK: 2/68, GDT: 1/80, and MDT: 1/69; P = 0.67). In the subgroup of ICDs connected to leads from other manufacturers, however, ventricular oversensing was observed in none of 19 GDT and MDT ICDs but in 4 of 9 BTK devices (44.4%, P = 0.012). These four cases of oversensing (three R-wave double-sensing and one TWO) all occurred in BTK ICDs connected to integrated bipolar ICD leads from other manufacturers.\n\nSignificant manufacturer-related differences exist in the incidence of ventricular oversensing in single- and dual-chamber ICD systems. Biotronik devices connected to integrated bipolar ICD leads from other manufacturers have an increased risk for R-wave double-sensing.”
“The subcellular localization of NO generation in soybean cotyledons, and the relationship between NO synthesis and in vivo chloroplast performance were studied. Employing the NO probe 4-aminomethyl-2′,7′-difluorofluorescein diacetate (DAF-FM DA) and fluorescence microscopy, a strongly punctuated fluorescence was detected in mesophyll cells.

However, a more detailed analysis using population pharmacokineti

However, a more detailed analysis using population pharmacokinetic modeling is needed to fully investigate the differences found for some of the pharmacokinetic parameters, such as the terminal half-life.”
“Aims: C-type natriuretic peptide (CNP) is a local regulator of vascular tone and remodeling in many vascular beds. However, the role of CNP in modulating pulmonary arterial hypertensive and vascular remodeling responses is unclear. The purpose GDC-0973 mouse of this study was to determine if CNP is capable of preventing the

development of pulmonary hypertension (PH).\n\nMain methods: We used animal models of PH caused by chronic hypoxia alone or in combination with the vascular endothelial growth Vorinostat clinical trial factor (VEGF) receptor blocker SU5416. We measured pulmonary hemodynamics, right ventricular hypertrophy and vascular remodeling effects in response to a continuous infusion of low dose or high dose CNP or vehicle placebo.\n\nKey findings: Right ventricular hypertrophy and a marked elevation in right ventricular systolic pressure (RVSP) were seen in both models of PH. Rats treated with the combination of SU5416 and chronic hypoxia also developed pulmonary endothelial hyperproliferative lesions. Continuous intravenous infusion of CNP at either dose did not attenuate the development of PH, right ventricular hypertrophy or vascular remodeling

in either of the models of PH despite a three-fold increase in serum CNP levels.\n\nSignificance: CNP does not prevent the development of PH in the chronic hypoxia or SU5416 plus hypoxia models of pulmonary hypertension suggesting that CNP may not play an important modulatory role in human PH. Published by Elsevier Inc.”
“In the title complex, [Cd(C10H5O8)(2)(C10H9N5)(2)(H2O)(2)]center dot 2H(2)O, the Cd-II ion lies on an inversion center and

is coordinated by two N atoms from two symmetry-related 1-[(1H-benzimidazol-2-yl)methyl]-1H-1,2,4-triazole ligands and two O atoms from two monodeprotonated 2,4,5-tricarboxybenzoate anions in equatorial positions and by two water O atoms in axial positions, leading to a distorted octahedral environment. In the crystal, complex molecules and solvent water molecules are linked through intermolecular O-H center dot center dot center dot O, O-H center dot center dot center dot N and CA4P mw N-H center dot center dot center dot O hydrogen bonds into a three-dimensional network. Intramolecular O-H center dot center dot center dot O hydrogen bonds are also present.”
“We retrospectively measured IgG antibody levels to BKV in pretransplant sera and compared levels in children who developed BK viremia to a control group who remained free of infection after transplantation. Sera from 45 renal transplant patients were available for analysis (BK viremia = 23, controls = 22). Serum BKV PCR levels ranged from 3400 to 6.5 million DNA copies/mL (mean +/- s.d.: 978K +/- 1.

29 per year of use; 95% CI 1 07, 1 55) or enfuvirtide (OR 1 28; 9

29 per year of use; 95% CI 1.07, 1.55) or enfuvirtide (OR 1.28; 95% CI 1.08, 1.52).\n\nConclusions: Around 1 in 10 men in the SHCS reported often experiencing ED. We found no association between ED and any drug class, but those exposed to zalcitabine or enfurvitide (drugs no longer or rarely used) were more likely to report ED; this second association was probably not causal.”
“Background. The influence of obesity on airway responsiveness remains controversial. Objective. This study

was designed to investigate airway responsiveness, airway inflammation, and the influence of sleep apnea syndrome (SAS), in severely obese subjects, before and after bariatric surgery. Methods. A total of 120 non-asthmatic obese patients were referred consecutively for pre-bariatric surgery evaluation. Lung function, airway responsiveness to methacholine, exhaled nitric oxide measurement, learn more and sleep studies were performed. Airway hyperresponsiveness (AHR) was defined as a 50% or greater increase in respiratory resistance measured using the forced oscillation technique in response to a methacholine dose <= 2000 mu g. Forced expiratory volume in 1 second (FEV(1)) was measured after the last methacholine dose. Airway responsiveness was reevaluated after

weight loss in patients with a pre-surgery AHR. Results. AHR was found in 16 patients. The percent FEV(1) decrease selleck or percent respiratory resistance increase in response to methacholine was related to baseline expiratory airflow (forced expiratory flow at 50%) (r = 0.26, p < .006 and r = 0.315, p =.0005, respectively) but not to body mass index (BMI) or exhaled nitric oxide.

Both airway responsiveness parameters were significantly related to forced expiratory flow at 25-75%/forced vital capacity, a measure of airway 5-Fluoracil size relative to lung size (r = 0.27, p < .005 and r = 0.25, p < .007, respectively). Sleep apnea was not significantly associated with AHR or airway inflammation. About 11 patients with AHR were reevaluated 18 months to 2 years after surgery, with no change in AHR associated with weight loss. Conclusion. Airway responsiveness is not related to BMI or to SAS. AHR in severely obese patients might be related to distal airway obstruction or low relative airway size.”
“Objectives: To examine how exhaled nitric oxide (eNO) levels measured before and after treatment of asthma exacerbations relate to emergency department (ED) disposition.\n\nMethods: We enrolled children 6 to 17 years old treated for asthma exacerbations in a pediatric ED. Using an offline single-breath eNO sampling technique, we collected replicate initial samples before treatment and replicate final samples when disposition was decided.

Data were extracted using a standardized form and pooled odd rati

Data were extracted using a standardized form and pooled odd ratios with 95% confidence intervals were calculated to evaluate the strength of the association. A total of seven case-control studies involving 1912 PD cases and 1740 controls were included, concerning two polymorphisms (-1082A/G and -592C/A) of IL-10 gene. No significant associations were found in the overall analysis for both -1082A/G and -592C/A

polymorphisms with PD risk. Similar lacking associations were observed in subgroup analysis based on ethnicity and age of onset. In conclusion, there is no enough evidence for association between IL-10 polymorphisms AZD5582 price (-1082A/G and -592C/A) and risk of PD at present. Well-designed studies with larger sample size and multi-ethnicity eFT-508 studies are

warranted in the future.”
“Among the parameters that characterize a solar cell and define its power-conversion efficiency, the fill factor is the least well understood, making targeted improvements difficult. Here we quantify the competition between charge extraction and recombination by using a single parameter theta, and we demonstrate that this parameter is directly related to the fill factor of many different bulk-heterojunction solar cells. Our finding is supported by experimental measurements on 15 different donor: acceptor combinations, as well as by drift-diffusion simulations of organic solar cells in which charge-carrier mobilities, recombination rate, light intensity, energy levels and active-layer AZD9291 cost thickness are all varied over wide ranges to reproduce typical experimental conditions. The results unify the

fill factors of several very different donor: acceptor combinations and give insight into why fill factors change so much with thickness, light intensity and materials properties. To achieve fill factors larger than 0.8 requires further improvements in charge transport while reducing recombination.”
“Despite therapeutic advantages, double-donor (DD) HSCTs present technical problems for molecular chimerism (CHM) monitoring. These DD chimeras contain three matched DNAs, so that the genomes of donor(s) and recipient often share the same alleles. In the STR assay, shared recipient/donor alleles are common and have identical physico-chemical properties. As a consequence of the latter, they co-migrate in the same band (‘shared peak’), which prevents measuring each allele separately. Without individual allelic measurements, the direct calculation of the chimeric recipient/donor DNA ratio is precluded. This is the first study to document and systematically examine these problems. Its goal was to provide a validated framework for accurate, routine monitoring based on a stepwise analytic paradigm for approximating percent CHM (%CHM) from shared STR-alleles. Analysis of STR-DNA from DD loci showed that at least four of six alleles were typically shared.


“Objective-To assess the effects of oxygen insufflation ra


“Objective-To assess the effects of oxygen insufflation rate, respiratory rate, and tidal volume on fraction of inspired oxygen (F-IO2) in cadaveric canine heads attached to a lung model.\n\nSample-16 heads of canine cadavers.\n\nProcedures-Each cadaver head was instrumented with a nasal insufflation catheter through which oxygen was delivered. The trachea was attached to a sample collection port connected by means of corrugated tubing to a lung model. Eight treatment combinations that varied in respiratory rate (10 or 20 breaths/min), tidal volume (10 or 15 mL/kg), and

oxygen insufflation rate (50 or 100 mL/kg/min) were applied to each head in a replicated Latin square design. Gas samples were manually collected, and inspired oxygen concentrations were analyzed. The F-IO2 and end-tidal CO2 STI571 nmr concentration were determined and compared among sample groups.\n\nResults Estimated least squares mean F-IO2 for various treatment

selleck chemicals llc combinations ranged from 32.2% to 60.6%. The F-IO2 was significantly increased at the higher insufflation rate (estimated marginal least squares mean, 48.7% vs 38.6% for 100 and 50 mL/kg/min, respectively), lower respiratory rate (48.9% vs 38.3% for 10 and 20 breaths/min, respectively), and smaller tidal volume (46.8% vs 40.0% for 10 and 15 mL/kg, respectively).\n\nConclusions and Clinical Relevance-F-IO2 in the model was affected by oxygen insufflation rate, respiratory rate, and tidal volume. This information Crenolanib datasheet may potentially help clinicians interpret results of blood gas analysis and manage canine patients receiving oxygen insufflation via a nasal catheter.”
“To evaluate the prevalence

of extended-spectrum cephalosporin (ESC)-resistant Enterobacteriaceae in broiler chickens, 41 rectal samples taken from 4 commercial farms were examined. Desoxytholate hydrogen sulfide lactose agars, supplemented with either 4 mu g/m/ cefotaxime or 16 mu g/ml ceftazidime, were used to screen ESC-resistant bacteria. ESC-resistant bacteria were isolated from all samples. Of the 164 ESC-resistant bacteria (included 4 isolates per a sample), 163 were Escherichia coli, while 1 isolate was identified as Enterobacter cloacae. Extended-spectrum beta-lactamase (ESBL) genes and plasmid-mediated AmpC beta-lactamase genes in the isolates were determined by PCR and sequencing. One AmpC beta-lactamase gene, bla(CMY-2) (66%), and 4 ESBL genes, bla(CTX-M-1), (26%), bla(CTX-M-55) (10%), bla(SHV-5) (4%) and bla(CTX-M-2) (3%), were detected in the E. coli isolates. The epidemiological relationship of the CMY-2 and CTX-M beta-lactamase-producing isolates among the farms was analyzed by pulsed-field gel electrophoresis using the Xbal restriction enzyme. Forty-one (Y1-Y41) and 14 (X1-X14) clusters were found in the CMY-2 and CTX-M-carrying E. coli isolates, respectively. Some clusters included isolates derived from more than 1 farm, indicating some cross-contamination of clonal strains and spread of CMY-2 AmpC beta-lactamase or CTX-M ESBL among the farms.

The results of present study revealed hypolipidemic effect of Tri

The results of present study revealed hypolipidemic effect of Triticum aestivum CH in hypercholesterolemic selleckchem rats by increasing fecal cholesterol excretion. Fresh GJ could have potentially beneficial effect in atherosclerosis associated with hyperlipidemia.”
“Purpose To review a series of closed liability claims for

upper extremity conditions to guide improvements for upper extremity care and thereby reduce the frequency of paid claims.\n\nMethods The authors, a team of 3 orthopedic surgeons and 3 nonphysician investigators experienced in closed claims research, investigated 108 closed upper extremity liability claims from a large United States wide insurer for events that occurred between 1996 and 2009. We sought to determine the types of conditions, treatments, and surgeon factors common to claims made and claims paid.\n\nResults Liability claims were primarily for the care of common problems, GDC-0994 such as fractures (n = 52; 48%) or degenerative conditions (n = 24; 26%), rather than complex challenging

conditions or disorders, such as deficiencies treated with replantations or tissue transfers. The most common adverse outcomes in these claims were nonunion or malunion of fractures (n = 29; 27%), nerve injury (n = 20; 19%), and infection (n = 13; 12%). Most claims (n = 57; 53%) involved a permanent injury. The surgeon’s operative skills were more commonly an issue in paid claims (n = 13; 45%) than in claims without payment (n = 14; 19%). Claims for mismanagement of fractures (n = 52; 48% of all claims) were more likely to result in payment (n = 20; 38%) than nonfracture claims (n = 10; 18%).\n\nConclusions P5091 This analysis suggests

that the incidence of upper extremity claims made and claims paid may be reduced if surgeons acquire and maintain the knowledge and skills necessary for the care of the common conditions they encounter, including fractures. (J Hand Surg Am. 2014;39(1):91-99. Copyright (C) 2014 by the American Society for Surgery of the Hand. All rights reserved.)\n\nType of study/level of evidence Prognostic II.”
“The current demand for environmentally degradable copolymers has initiated the use of novel degradable copolyesters. One of them is a copolyester based on poly(ethylene terephthalate-co-glycolic acid) (PET-GLA). The copolymer was synthesized by the melt reaction of bis-2-hydroxyethyl terephthalate (BHET) with glycolic acid (GLA) oligomers in the presence of Sb(2)O(3) as a catalyst.\n\nHydrolytic degradation of the copolymer was carried out in two buffered Solutions at 45 degrees C: degradation was studied by incubating samples in powder form, in a concentrated Solution from 30 to 150 days. The copolymer before and after degradation was characterized by means of different analytical techniques.

In addition, patients with C reactive

protein level >

In addition, patients with C reactive

protein level > 5 mg/L achieved remission more significantly than patients with normal values, thus suggesting that the symptoms were probably caused by inflammation instead of by non-inflammatory causes. We also analyze the role of rifaximin against gut bacteria and the clinical situations that could obtain the best results from antibiotics. (C) 2013 Baishideng Publishing Group Co., Limited. All rights reserved.”
“Objective: Group training in communication see more skills [communication skills training (CST)] has become partly mandatory for oncology staff. However, so far, a comprehensive meta-analysis on the efficacy is lacking.\n\nDesign: Included studies either compare the efficacy of a specific training with a control group or look at the additional effect of booster sessions on communication behaviour, attitudes or patient outcomes.\n\nMethods: Four electronic databases were searched up to July 2008 without language restriction, and reference lists of earlier reviews were screened. Effect sizes (ESs) were extracted and pooled in random effects meta-analyses.\n\nResults:

We included 13 trials (three non-randomised), 10 with no specific intervention in the control group. Meta-analysis showed a moderate effect of CST on communication behaviour ES = 0.54. Three trials compared basic training courses with more extensive training courses selleck chemical and showed a small additional effect on communication skills ES = 0.37. Trials investigating participants’ attitudes ES = 0.35 and patient outcomes ES =

0.13 (trend) confirmed this effect.\n\nConclusions: Training health professionals by CST is a promising approach to change communication behaviour and attitudes. Patients might also benefit from specifically trained health professionals but strong studies are lacking. However, feasibility selleck screening library and economic aspects have to be kept in mind when considering providing a training of optimal length.”
“The synthesis of gentiooligosaccharides of genistein and glycitein using cultured cells of Eucalyptus perriniana as biocatalysts was investigated. The cells of E. perriniana glycosylated genistein and glycitein to give the corresponding 4′-O-beta-glucosides, 7-O-beta-glucosides, and 7-O-beta-gentiobiosides, which were two new compounds. The beta-glucosides of genistein and glycitein showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity and superoxide-radical scavenging activity. On the other hand, 7-O-beta-glucosides of genistein and glycitein and the 7-O-beta-gentiobioside of glycitein exerted inhibitory effects on IgE antibody production.

These results may be helpful in providing historical controls for

These results may be helpful in providing historical controls for understanding the efficacy of new treatment paradigms,

patient education, and guiding level of aggressiveness in treatment strategies. (DOI: 10.3171/2010.10.SPINE10189)”
“The ethnobotanical studies indicated that the inhabitants of Poonch Valley utilized 169 plant species for more than 30 domestic needs. The major usage include 68 medicinal plants, 35 fuel wood species, 35 fodder species, 24 vegetable and pot herbs, 10 veterinary medicinal plants, 24 fruit yielding plants, 14 spices and condiment species, 12 for construction and timber requirements, 13 ornamental species, 9 used as field fencing, 13 furniture making species, and 6 used as mouth wash (maswak). Other miscellaneous uses of plants included agricultural tools, thatching and roofing, basket making, cosmetics, dish cleaners, home decoration, narcotic, anti-snake and scorpion bite, soil binding, www.selleckchem.com/products/tariquidar.html selleck screening library stick/handles, shade tree, utensil making and pillow filling. Results of the survey conducted revealed that 72% of folk medicinal knowledge comes from people above the age of 50 years, while 28% of it comes from people

between the ages of 30 and 50. The survey also indicated that men especially old ones are more informative of traditional knowledge of medicinal plants than women in the area.”
“The bronchial involvement of diffuse large B-cell lymphoma (DLBCL) is an exceptional finding. Histological diagnosis is done with lung tissue samples. In these cases, the need for immunohistochemistry studies in order to establish the diagnosis requires obtaining SN-38 price tissue samples of adequate size and quality. Sometimes, endoscopic explorations may be repeated to obtain further biopsies.\n\nWe present the first documented

case of recurrent endobronchial DLBCL that was diagnosed from a bronchial biopsy taken with a cryoprobe. (C) 2012 SEPAR. Published by Elsevier Espana, S.L. All rights reserved.”
“Over two thirds of the world’s turtle species are in decline as a result of habitat destruction and harvesting. Quantitative methods for predicting the risk of extinction of turtle populations are essential for status assessments and recovery planning. Spotted turtles (Clemmys guttata (Schneider, 1792)) are considered vulnerable internationally, and endangered in Canada. We used population viability analysis to assess the risk of extirpation of a Georgian Bay, Ontario, population that has been under study since 1977 and of nine Ontario populations for which population size is known, and to examine the effects of dispersal between breeding ponds on population persistence. A simple stochastic model for the Georgian Bay population projected a 60% probability of extirpation in 100 years. A metapopulation model for the same study area projected an 18% probability of extirpation within 100 years, suggesting that dispersal between breeding ponds is important for population persistence.