Measuring Membrane Protein Dimerization Equilibrium in Lipid Bilayers by Single-Molecule Fluorescence Microscopy.

Dimerization of membrane protein interfaces occurs during membrane protein folding and cell receptor signaling. Here, we summarize a method that allows for measurement of equilibrium dimerization reactions of membrane proteins in lipid bilayers, by measuring the Poisson distribution of subunit capture into liposomes by single-molecule photobleaching analysis. This strategy is grounded in the fact that given a comparable labeling efficiency, monomeric or dimeric forms of a membrane protein will give rise to distinctly different photobleaching probability distributions. These methods have been used to verify the dimer stoichiometry of the Fluc F- ion channel and the dimerization equilibrium constant of the ClC-ec1 Cl-/H+ antiporter in lipid bilayers. This approach can be applied to any membrane protein system provided it can be purified, fluorescently labeled in a quantitative manner, and verified to be correctly folded by functional assays, even if the structure is not yet known.

Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station.

Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm(2) to 20 × 20 mm(2). This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

Fungal Planet description sheets: 214-280.

Novel species of microfungi described in the present study include the following from South Africa: Cercosporella dolichandrae from Dolichandra unguiscati, Seiridium podocarpi from Podocarpus latifolius, Pseudocercospora parapseudarthriae from Pseudarthria hookeri, Neodevriesia coryneliae from Corynelia uberata on leaves of Afrocarpus falcatus, Ramichloridium eucleae from Euclea undulata and Stachybotrys aloeticola from Aloe sp. (South Africa), as novel member of the Stachybotriaceae fam. nov. Several species were also described from Zambia, and these include Chaetomella zambiensis on unknown Fabaceae, Schizoparme pseudogranati from Terminalia stuhlmannii, Diaporthe isoberliniae from Isoberlinia angolensis, Peyronellaea combreti from Combretum mossambiciensis, Zasmidium rothmanniae and Phaeococcomyces rothmanniae from Rothmannia engleriana, Diaporthe vangueriae from Vangueria infausta and Diaporthe parapterocarpi from Pterocarpus brenanii. Novel species from the Netherlands include: Stagonospora trichophoricola, Keissleriella trichophoricola and Dinemasporium trichophoricola from Trichophorum cespitosum, Phaeosphaeria poae, Keissleriella poagena, Phaeosphaeria poagena, Parastagonospora poagena and Pyrenochaetopsis poae from Poa sp., Septoriella oudemansii from Phragmites australis and Dendryphion europaeum from Hedera helix (Germany) and Heracleum sphondylium (the Netherlands). Novel species from Australia include: Anungitea eucalyptorum from Eucalyptus leaf litter, Beltraniopsis neolitseae and Acrodontium neolitseae from Neolitsea australiensis, Beltraniella endiandrae from Endiandra introrsa, Phaeophleospora parsoniae from Parsonia straminea, Penicillifer martinii from Cynodon dactylon, Ochroconis macrozamiae from Macrozamia leaf litter, Triposporium cycadicola, Circinotrichum cycadis, Cladosporium cycadicola and Acrocalymma cycadis from Cycas spp. Furthermore, Vermiculariopsiella dichapetali is described from Dichapetalum rhodesicum (Botswana), Ophiognomonia acadiensis from Picea rubens (Canada), Setophoma vernoniae from Vernonia polyanthes and Penicillium restingae from soil (Brazil), Pseudolachnella guaviyunis from Myrcianthes pungens (Uruguay) and Pseudocercospora neriicola from Nerium oleander (Italy). Novelties from Spain include: Dendryphiella eucalyptorum from Eucalyptus globulus, Conioscypha minutispora from dead wood, Diplogelasinospora moalensis and Pseudoneurospora canariensis from soil and Inocybe lanatopurpurea from reforested woodland of Pinus spp. Novelties from France include: Kellermania triseptata from Agave angustifolia, Zetiasplozna acaciae from Acacia melanoxylon, Pyrenochaeta pinicola from Pinus sp. and Pseudonectria rusci from Ruscus aculeatus. New species from China include: Dematiocladium celtidicola from Celtis bungeana, Beltrania pseudorhombica, Chaetopsina beijingensis and Toxicocladosporium pini from Pinus spp. and Setophaeosphaeria badalingensis from Hemerocallis fulva. Novel genera of Ascomycetes include Alfaria from Cyperus esculentus (Spain), Rinaldiella from a contaminated human lesion (Georgia), Hyalocladosporiella from Tectona grandis (Brazil), Pseudoacremonium from Saccharum spontaneum and Melnikomyces from leaf litter (Vietnam), Annellosympodiella from Juniperus procera (Ethiopia), Neoceratosperma from Eucalyptus leaves (Thailand), Ramopenidiella from Cycas calcicola (Australia), Cephalotrichiella from air in the Netherlands, Neocamarosporium from Mesembryanthemum sp. and Acervuloseptoria from Ziziphus mucronata (South Africa) and Setophaeosphaeria from Hemerocallis fulva (China). Several novel combinations are also introduced, namely for Phaeosphaeria setosa as Setophaeosphaeria setosa, Phoma heteroderae as Peyronellaea heteroderae and Phyllosticta maydis as Peyronellaea maydis. Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

Development of a compact in situ polarized ³He neutron spin filter at Oak Ridge National Laboratory.

We constructed a compact in situ polarized (3)He neutron spin filter based on spin-exchange optical pumping which is capable of continuous pumping of the (3)He gas while the system is in place in the neutron beam on an instrument. The compact size and light weight of the system simplifies its utilization on various neutron instruments. The system has been successfully tested as a neutron polarizer on the triple-axis spectrometer (HB3) and the hybrid spectrometer (HYSPEC) at Oak Ridge National Laboratory. Over 70% (3)He polarization was achieved and maintained during the test experiments. Over 90% neutron polarization and an average of 25% transmission for neutrons of 14.7 meV and 15 meV was also obtained.

Effect of blood in the cerebrospinal fluid on the accuracy of cerebral oxygenation measured by near infrared spectroscopy.

Near infrared spectroscopy (NIRS) is an optical technique used to examine the oxygenation state of tissues such as the brain in patients, including those with brain injury. We have examined the effect of a cerebrospinal fluid (CSF) contaminant, specifically haemoglobin, on the sensitivity of cerebral NIRS signals through computer simulation. Previous models of light transport in the head have shown that the clear CSF layer has a profound effect on the sensitivity profile of the NIRS signal due to its low absorbing, low scattering qualities. In subarachnoid haemorrhage, which may accompany brain injury, the principal near infrared chromophore, haemoglobin, is released into the CSF. Sensitivity was measured through forward modeling and the presence of haemoglobin within the CSF was modeled by increasing the absorption coefficient of the layer, with sensitivity quantified in terms of the partial pathlength of light within the brain. The model demonstrated that increases in the CSF absorption led to a marked decrease in the sensitivity to changes in the brain layer. This suggests that blood or other contaminants in the CSF may have a significant effect on the utility of NIRS for measurement of cerebral oxygenation, and merits further investigation.

In vitro and numerical support for combinatorial irreversible electroporation and electrochemotherapy glioma treatment.

Irreversible electroporation (IRE) achieves targeted volume non-thermal focal ablation using a series of brief electric pulses to kill cells by disrupting membrane integrity. Electrochemotherapy (ECT) uses lower numbers of sub-lethal electric pulses to disrupt membranes for improved drug uptake. Malignant glioma (MG) brain tumors are difficult to treat due to diffuse peripheral margins into healthy neural tissue. Here, in vitro experimental data and numerical simulations investigate the feasibility for IRE-relevant pulse protocols with adjuvant ECT drugs to enhance MG treatment. Cytotoxicity curves were produced on two glioma cell lines in vitro at multiple pulse strengths and drug doses with Bleomycin or Carboplatin. Pulses alone increased cytotoxicity with higher pulse numbers and strengths, reaching >90% by 800 V/cm with 90 pulses. Chemotherapeutic addition increased cytotoxicity by >50% for 1 ng/mL concentrations of either drug relative to 80 pulses alone with J3T cells at electric fields ≥400 V/cm. In addition to necrosis, transmission electron microscopy visualizes apoptotic morphological changes and Hoescht 33342 staining shows apoptotic cell fractions varying with electric field and drug dose relative to controls. Numerically simulated treatment volumes in a canine brain show IRE combined with ECT expands therapeutic volume by 2.1-3.2 times compared to IRE alone.

Instrument performance study on the short and long pulse options of the second Spallation Neutron Source target station.

The Spallation Neutron Source (SNS) facility at the Oak Ridge National Laboratory is designed with an upgrade option for a future low repetition rate, long wavelength second target station. This second target station is intended to complement the scientific capabilities of the 1.4 MW, 60 Hz high power first target station. Two upgrade possibilities have been considered, the short and the long pulse options. In the short pulse mode, proton extraction occurs after the pulse compression in the accumulator ring. The proton pulse structure is thus the same as that for the first target station with a pulse width of ~0.7 µs. In the long pulse mode, protons are extracted as they are produced by the linac, with no compression in the accumulator ring. The time width of the uncompressed proton pulse is ~1 ms. This difference in proton pulse structure means that neutron pulses will also be different. Neutron scattering instruments thus have to be designed and optimized very differently for these two source options which will directly impact the overall scientific capabilities of the SNS facility. In order to assess the merits of the short and long pulse target stations, we investigated a representative suit of neutron scattering instruments and evaluated their performance under each option. Our results indicate that the short pulse option will offer significantly better performance for the instruments and is the preferred choice for the SNS facility.

Intramedullary spinal cord neoplasia in 53 dogs (1990-2010): distribution, clinicopathologic characteristics, and clinical behavior.

BACKGROUND: Intramedullary neoplasms of the canine spinal cord are infrequently reported. OBJECTIVE: To describe distribution, clinicopathologic characteristics, radiographic findings, and clinical features of canine intramedullary spinal tumors. METHODS: Retrospective series of histologically confirmed canine intramedullary spinal tumors. Contingency tables were generated for categorical variables (breed, sex, treatment, pain, chief complaint, localization, histology, imaging, and site). Associations were assessed by Fisher's exact, Wilcoxon rank sum test, t-test, and one-way ANOVA. RESULTS: Intramedullary spinal cord tumors comprised 16% (53/331) of all tumors of the spinal cord. Primary tumors were diagnosed in 66% (35/53) of cases, with neuroepithelial-origin tumors comprising 51% (18/35) of all primary neoplasms. Intraparenchymal metastases of transitional cell carcinoma and hemangiosarcoma accounted for 66% (6/18 each) of all secondary tumors. Primary tumors were more likely to affect younger dogs. Dogs with intramedullary metastases were most commonly presented for primary myelopathic signs (8/18, 44%). The majority of all tumors (52.8%) occurred in the T3-L3 spinal cord segments. All dogs with cervical neurolocalization had primary tumors. Dogs with metastatic lesions had a shorter duration of clinical signs before presentation, but there was no difference in survival time between dogs with primary as compared with secondary tumors. CONCLUSIONS: Intramedullary spinal cord tumors are uncommon. Primary intramedullary spinal cord tumors are more common than secondary intramedullary spinal cord tumors and tend to occur in the cervical spinal cord of younger dogs. Intramedullary metastases occur in older dogs, are rarely asymptomatic, and neurologic dysfunction is a common clinical presentation. Dogs with primary tumors may have a protracted clinical course compared with those with intramedullary metastases.

Spin exchange optical pumping based polarized 3He filling station for the Hybrid Spectrometer at the Spallation Neutron Source.

The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60° horizontal and 15° vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized (3)He filling station based on the spin exchange optical pumping method. It is designed to supply polarized (3)He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the (3)He pressure with respect to the scattered neutron energies. The depolarized (3)He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

Optimizing moderator dimensions for neutron scattering at the spallation neutron source.

In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter).

Multi-ion distributions in the cytoplasmic domain of inward rectifier potassium channels.

Inward rectifier potassium (Kir) channels act as cellular diodes, allowing unrestricted flow of potassium (K(+)) into the cell while preventing currents of large magnitude in the outward direction. The rectification mechanism by which this occurs involves a coupling between K(+) and intracellular blockers-magnesium (Mg(2+)) or polyamines-that simultaneously occupy the permeation pathway. In addition to the transmembrane pore, Kirs possess a large cytoplasmic domain (CD) that provides a favorable electronegative environment for cations. Electrophysiological experiments have shown that the CD is a key regulator of both conductance and rectification. In this study, we calculate and compare averaged equilibrium probability densities of K(+) and Cl(-) in open-pore models of the CDs of a weak (Kir1.1-ROMK) and a strong (Kir2.1-IRK) rectifier through explicit-solvent molecular-dynamics simulations in ~1 M KCl. The CD of both channels concentrates K(+) ions greater than threefold inside the cytoplasmic pore while IRK shows an additional K(+) accumulation region near the cytoplasmic entrance. Simulations carried out with Mg(2+) or spermine (SPM(4+)) show that these ions interact with pore-lining residues, shielding the surface charge and reducing K(+) in both channels. The results also show that SPM(4+) behaves differently inside these two channels. Although SPM(4+) remains inside the CD of ROMK, it diffuses around the entire volume of the pore. In contrast, this polyatomic cation finds long-lived conformational states inside the IRK pore, interacting with residues E224, D259, and E299. The strong rectifier CD is also capable of sequestering an additional SPM(4+) at the cytoplasmic entrance near a cluster of negative residues D249, D274, E275, and D276. Although understanding the actual mechanism of rectification blockade will require high-resolution structural information of the blocked state, these simulations provide insight into how sequence variation in the CD can affect the multi-ion distributions that underlie the mechanisms of conduction, rectification affinity, and kinetics.

In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source.

We report on the in situ polarized (3)He neutron polarization analyzer developed for the time-of-flight Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Using the spin exchange optical pumping method, we achieved a (3)He polarization of 76% ± 1% and maintained it for the entire three-day duration of the test experiment. Based on transmission measurements with unpolarized neutrons, we show that the average analyzing efficiency of the (3)He system is 98% for the neutron wavelength band of 2-5 Å. Using a highly polarized incident neutron beam produced by a supermirror bender polarizer, we obtained a flipping ratio of >100 with a transmission of 25% for polarized neutrons, averaged over the wavelength band of 2-5 Å. After the cell was depolarized for transmission measurements, it was reproducibly polarized and this performance was maintained for three weeks. A high quality polarization analysis experiment was performed on a reference sample of Fe/Cr multilayer with strong spin-flip off-specular scattering. Using a combination of the position sensitive detector, time-of-flight method, and the excellent parameters of the (3)He cell, the polarization analysis of the two-dimensional maps of reflected, refracted, and off-specular scattered intensity above and below the horizon were obtained, simultaneously.

Non-thermal irreversible electroporation (N-TIRE) and adjuvant fractionated radiotherapeutic multimodal therapy for intracranial malignant glioma in a canine patient.

Non-thermal irreversible electroporation (N-TIRE) has shown promise as an ablative therapy for a variety of soft-tissue neoplasms. Here we describe the therapeutic planning aspects and first clinical application of N-TIRE for the treatment of an inoperable, spontaneous malignant intracranial glioma in a canine patient. The N-TIRE ablation was performed safely, effectively reduced the tumor volume and associated intracranial hypertension, and provided sufficient improvement in neurological function of the patient to safely undergo adjunctive fractionated radiotherapy (RT) according to current standards of care. Complete remission was achieved based on serial magnetic resonance imaging examinations of the brain, although progressive radiation encephalopathy resulted in the death of the dog 149 days after N-TIRE therapy. The length of survival of this patient was comparable to dogs with intracranial tumors treated via standard excisional surgery and adjunctive fractionated external beam RT. Our results illustrate the potential benefits of N-TIRE for in vivo ablation of undesirable brain tissue, especially when traditional methods of cytoreductive surgery are not possible or ideal, and highlight the potential radiosensitizing effects of N-TIRE on the brain.

Enhanced ordering temperatures in antiferromagnetic manganite superlattices.

The disorder inherent to doping by cation substitution in the complex oxides can have profound effects on collective-ordered states. Here, we demonstrate that cation-site ordering achieved through digital-synthesis techniques can dramatically enhance the antiferromagnetic ordering temperatures of manganite films. Cation-ordered (LaMnO3)m/(SrMnO3)2m superlattices show Néel temperatures (TN) that are the highest of any La(1-x)Sr(x)MnO3 compound, approximately 70 K greater than compositionally equivalent randomly doped La(1/3)Sr(2/3)MnO3. The antiferromagnetic order is A-type, consisting of in-plane double-exchange-mediated ferromagnetic sheets coupled antiferromagnetically along the out-of-plane direction. Through synchrotron X-ray scattering, we have discovered an in-plane structural modulation that reduces the charge itinerancy and hence the ordering temperature within the ferromagnetic sheets, thereby limiting TN. This modulation is mitigated and driven to long wavelengths by cation ordering, enabling the higher TN values of the superlattices. These results provide insight into how cation-site ordering can enhance cooperative behaviour in oxides through subtle structural phenomena.

Cyclooxygenase-2 (COX-2) expression in canine intracranial meningiomas.

Meningiomas are the most common canine intracranial tumour. Neurologic disability and death from treatment failure remain problematic despite current surgical and radiotherapeutic treatments for canine intracranial meningiomas. Cyclooxygenase-2 (COX-2) over-expression has been demonstrated in multiple canine malignancies, and COX-2 inhibitory treatment strategies have been shown to have both preventative and therapeutic effects in spontaneous and experimental models of cancer. The purpose of this study was to evaluate COX-2 expression in canine intracranial meningiomas. Immunohistochemical and Western blot (WB) analyses showed COX-2 expression in multiple tissues of the normal canine brain, and 87% (21/24) of intracranial meningiomas studied were immunoreactive to COX-2. No significant associations between COX-2 immunoreactivity and tumour grade were identified. Further studies are required to elucidate the physiologic roles of constitutive COX-2 expression in the central nervous system as well as its participation in meningioma tumourigenesis.

Orientational distributions and nematic order of rodlike magnetic nanoparticles in dispersions.

Using small-angle neutron scattering (SANS), we have investigated the orientational order of iron nanoparticles dispersed in cyclohexanone. The particles have rodlike shape and size distributions with an average length of 200 nm and an average diameter of 25 nm. SANS shows an anisotropy, which is a measure of orientational order, in magnetic dispersions with a volume fraction of 3.2% and 3.9% iron particles in shear flow and/or magnetic field. The scattering anisotropy can be fitted by a model assuming an Onsager distribution of the orientation of the particles in shear flow. The orientational distribution of particles oriented by a magnetic field can be described by a different model assuming the Maier-Saupe orientational distribution for uniaxial ferromagnetic particles. The orientational distribution parameter m for the Maier-Saupe distribution or alpha for the Onsager distribution and the orientational order parameter S have been determined at shear rates gamma[over ] of to 0-4000 s(-1) and in magnetic fields of 0-18 mT. The S values indicate that the particles start to orient either in a shear flow of 100 s(-1) or in a magnetic field of 6 mT. Applying only shear results in an orientational order, with the dispersion returning to the disordered state when the shear rate is decreased to zero. In sharp contrast, application of magnetic fields greater than 6 mT results in orientational order in the field-increasing cycle, and two-thirds of the orientational order remains when the field is decreased to zero. This shows that the order in a magnetic field is different from the order in a shear flow, the action of magnetizing the particles along a certain direction is irreversible, and the orientational order parameter exhibits hysteresis.

Ferrimagnetism in EuFe4Sb12 due to the interplay of f-electron moments and a nearly ferromagnetic host.

We combine x-ray magnetic circular dichroism spectroscopy at Fe L2,3 edges, at Eu M4,5 edges, x-ray absorption spectroscopy (XAS) investigation of Eu valence, and local spin density calculations, to show that the filled skutterudite Eu0.95Fe4Sb12 is a ferrimagnet in which the Fe 3d moment and the Eu2+ 4f moment are magnetically ordered with dominant antiferromagnetic coupling. From Eu L3 edge XAS, we find that about 13% of the Eu have a formal valence of 3+. We ascribe the origin of ferrimagnetism at a relatively high transition temperature TC of 85 K in Eu0.95Fe4Sb12 to f-electron interaction with the nearly ferromagnetic [Fe4Sb12]2.2- host lattice.

Critical evaluation of the modified-adult immersion test with discriminating dose bioassay for Boophilus microplus using American and Australian isolates.

Similar adult immersion tests (AITs) for acaricide susceptibility of Boophilus microplus were done in Texas, USA (Muñoz strain) and in Queensland, Australia (N-strain and Ultimo isolates). Engorged adult female ticks were immersed in one of a series of dilutions of commercial acaricide in water and then incubated at room temperature for 7 days. Data on oviposition were collected 7 days after exposure to acaricide and subjected to probit analysis. For most data, we observed poor fit to the probit model. Substantial differences in both LC50 and LC99 for the susceptible strains occurred between the respective laboratories and confidence intervals for all acaricides and all strains were unacceptably wide. For amitraz, the discriminating concentration (double the LC99.9 or LC99) recommended by FAO was 0.25%, but our estimates ranged from 0.46% to 9000%. For cypermethrin, the recommended DD was 0.0050%, with our estimates ranging from 0.00022% to 0.74%. For coumaphos the recommended DD was 0.50% but our estimates ranged from 0.66% to 130%. Finally, for moxidectin, the recommended DD was 0.10%, while our estimates ranged from <0.0001% to 5.9%. The method does not provide a means to discriminate between amitraz-susceptible and -resistant, nor between cypermethrin-susceptible and -resistant B. microplus.

Endostatin and vascular endothelial growth factor concentrations in healthy dogs, dogs with selected neoplasia, and dogs with nonneoplastic diseases.

To evaluate the relationship between endostatin and vascular endothelial growth factor (VEGF) in cancers of dogs, circulating concentrations of these 2 tumor-associated markers were measured prospectively in healthy dogs (n = 44), dogs with tumors (n = 54), and dogs with nonneoplastic diseases (n = 42 for endostatin; n = 16 for VEGF). A canine-directed enzyme-linked immunosorbent assay kit was used for determination of endostatin, and a human-directed kit was validated for detection of canine VEGF. Concentrations of endostatin for all dogs were 28-408 ng/mL. Increasing serum endostatin concentration was associated with increasing age (P = .0396). Concentrations of endostatin were not different among groups of dogs (P = .1989) when adjusted for age. Mean endostatin concentrations for all dogs were higher in dogs (P = .0124) with detectable VEGF concentrations. Endostatin concentrations, when corrected for age, were related to decreasing PCV (P = .032) but not white blood cell count (P = .225) or platelet count (P = .1990). Measurable VEGF (> or = 2.5 pg/mL) was detected in 3 (7.0%) of 43 healthy dogs. Dogs with tumors had detectable VEGF in 24 (44%) of 54 dogs, with concentrations ranging from 2.5-274 pg/mL; only 1 dog with a nonneoplastic disease process had detectable VEGF. VEGF concentrations for all dogs after correcting for age, endostatin, and disease categories were associated with increased white blood cell count (P = .0032) and platelet counts (P = .0064) and decreased PCV (P = .0017). Linkage between increased endostatin and VEGF concentrations suggests that similar factors may influence concentrations of these markers. Further evaluation of endostatin and VEGF associations in dogs with tumors may provide information on the extent and progression of the disease.

Complexity, fractals, disease time, and cancer.

Despite many years of research, a method to precisely and quantitatively determine cancer disease state remains elusive. Current practice for characterizing solid tumors involves the use of varying systems of tumor grading and staging and thus leaves diagnosis and clinical staging dependent on the experience and skill of the physicians involved. Although numerous disease markers have been identified, no combination of them has yet been found that produces a quantifiable and reliable measure of disease state. Newly developed genomic markers and other measures based on the developing sciences of complexity offer promise that this situation may soon be changed for the better. In this paper, we examine the potential of two measures of complexity, fractal dimension and percolation, for use as components of a yet to be determined "disease time" vector that more accurately quantifies disease state. The measures are applied to a set of micrographs of progressive rat hepatoma and analyzed in terms of their correlation with cell differentiation, ratio of tumor weight to rat body weight and tumor growth time. The results provide some support for the idea that measures of complexity could be important elements of any future cancer "disease time" vector.