A model to calculate the induced dose rate around an 18 MV ELEKTA linear accelerator.

The dose rate due to activity induced by (gamma, n) reactions around an ELEKTA Precise accelerator running at 18 MV is reported. A model to calculate the induced dose rate for a variety of working practices has been derived and compared to the measured values. From this model, the dose received by the staff using the machine can be estimated.

Prediction of the benefits from dose-escalated hypofractionated intensity-modulated radiotherapy for prostate cancer.

Purpose: To estimate the benefits of dose escalation in hypofractionated intensity-modulated radiotherapy (IMRT) for prostate cancer, using radiobiologic modeling and incorporating positional uncertainties of organs.

Materials And Methods: Biologically based mathematical models for describing the relationships between tumor control probability (TCP) and normal-tissue complication probability (NTCP) vs. dose were used to describe some of the results available in the literature.

A new class of hybrid materials via salt inclusion: novel copper(II) arsenates Na(5)ACu(4)(AsO(4))(4)Cl(2) (A = Rb, Cs) composed of alternating covalent and ionic lattices.

Two novel copper(II) arsenates Na5ACu4(AsO4)4Cl2 (A = Rb, Cs) were synthesized by conventional solid-state methods using reactive molten salt media. These compounds are isostructural and crystallize in an orthorhombic lattice (Fmmm, No. 69; Z = 8).

Sarcocystis neurona: parasitemia in a severe combined immunodeficient (SCID) horse fed sporocysts.

Sarcocystis neurona was isolated from the blood of a 5-month-old Arabian foal with severe combined immunodeficiency. The foal had been inoculated approximately 3 weeks previously with 5 x 10(5) sporocysts that were isolated from the intestines of an opossum and identified by restriction enzyme analysis of PCR products as S. neurona.

Indexing artefacts using a tertiary collimator and a method to avoid them.

A tertiary, slotted grid collimator has been proposed as a method by which the spatial resolution of radiation fields shaped using a multileaf collimator (MLC) may be improved. The prototype device previously reported in the literature allowed each slot in the grid to be aligned with each pair of opposing leaves in the MLC. Irradiation through the collimator resulted in a regular pattern of high dose strips, with the width of each strip defined by the width of the slot and the length by the relative separation of the MLC leaf pair.

Cytokine induction in pulmonary airways of horses with heaves and effect of therapy with inhaled fluticasone propionate.

Work in humans and laboratory animals has identified a central role for cytokines and chemokines in development and persistence of lower airway inflammation. The objectives of this study were to determine interleukin (IL)-1 beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha induction in bronchoalveolar lavage (BAL) of control horses and horses with heaves both during remission and exacerbation of the disease, and to determine the effect of therapy with inhaled fluticasone propionate on the cytokine profile of horses with heaves. IL-1 beta and TNF-alpha mRNA expression was significantly higher in horses with heaves after exposure to moldy hay compared to either values obtained during clinical remission or to healthy controls.

Optimizing the indexing of a resolution-enhancing tertiary collimator for radiotherapy.

A method for improving the resolution of multileaf collimator (MLC) defined radiotherapy fields using a tertiary, slotted grid collimator has been investigated and developed further. The original concept was for each slot to be aligned with each leaf pair of opposing MLC leaves. The total treated area is composed of a series of sub-fields, a pattern of irradiated strips, with the width of each strip defined by the width of the slot and the length by the relative separation of the MLC leaf pair.

The required number of treatment imaging days for an effective off-line correction of systematic errors in conformal radiotherapy of prostate cancer--a radiobiological analysis.

Background And Purpose: To use radiobiological modelling to estimate the number of initial days of treatment imaging required to gain most of the benefit from off-line correction of systematic errors in the conformal radiation therapy of prostate cancer.

Materials And Methods: Treatment plans based on the anatomical information of a representative patient were generated assuming that the patient is treated with a multi leaf collimator (MLC) four-field technique and a total isocentre dose of 72 Gy delivered in 36 daily fractions. Target position variations between fractions were simulated from standard deviations of measured data found in the literature.

Type II tumour necrosis factor-alpha receptor (TNFR2) activates c-Jun N-terminal kinase (JNK) but not mitogen-activated protein kinase (MAPK) or p38 MAPK pathways.

The pleitropic actions of tumour necrosis factor-alpha (TNF) are transmitted by the type I 55 kDa TNF receptor (TNFR1) and type II 75 kDa TNF receptor (TNFR2), but the signalling mechanisms elicited by these two receptors are not fully understood. In the present study, we report for the first time subtype-specific differential kinase activation in cell models that respond to TNF by undergoing apoptotic cell death. KYM-1 human rhabdomyosarcoma cells and HeLa human cervical epithelial cells, engineered to overexpress TNFR2, displayed c-Jun N-terminal kinase (JNK) activation by wild-type TNF, a TNFR1-specific TNF mutant and a TNFR2-specific mutant TNF in combination with an agonistic TNFR2-specific monoclonal antiserum.

Efficacy of ponazuril 15% oral paste as a treatment for equine protozoal myeloencephalitis.

Equine protozoal myeloencephalitis (EPM) is a neurologic disease of horses most commonly caused by the protozoan parasite Sarcocystis neurona. Until recently the only treatment option was the combination of a sulfonamide with pyrimethamine. The present study was performed to assess the efficacy of ponazuril, an anticoccidial triazine-based compound, as a treatment for naturally occurring EPM.

The striped skunk (Mephitis mephitis) is an intermediate host for Sarcocystis neurona.

Striped skunks, initially negative for antibodies to Sarcocystis neurona, formed sarcocysts in skeletal muscles after inoculation with S. neurona sporocysts collected from a naturally infected Virginia opossum (Didelphis virginiana). Skunks developed antibodies to S.

The burden of symptoms of asthma, allergic rhinoconjunctivitis and atopic eczema in children and adolescents in six New Zealand centres: ISAAC Phase One.

Aim: To describe the burden of symptoms of asthma, allergic rhinoconjunctivitis and atopic eczema in children in six New Zealand centres.

Methods: The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One was undertaken in Auckland, Bay of Plenty, Hawke's Bay, Wellington, Nelson and Christchurch during 1992-1993. In each centre, approximately 3,000 six to seven year old children and 3,000 thirteen to fourteen year old adolescents were studied, a total of 37,592 participants.

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host for Sarcocystis neurona.

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host of at least three species of Sarcocystis, Sarcocystis dasypi, Sarcocystis diminuta, and an unidentified species; however, life cycles of these species have not been determined. Following feeding of armadillo muscles containing sarcocysts to the Virginia opossum (Didelphis virginiana), the opossums shed sporulated Sarcocystis sporocysts in their faeces. Mean dimensions for sporocysts were 11.

The nine-banded armadillo (Dasypus novemcinctus) is naturally infected with Sarcocystis neurona.

Sarcocysts were dissected from the tongue of a nine-banded armadillo (Dasypus novemcinctus). DNA was extracted and characterised by PCR amplification followed by restriction fragment length polymorphism analysis and nucleotide sequencing. A total of 1879 nucleotides were compared; the sarcocyst DNA sequence was identical to that reported for Sarcocystis neurona.

Development of Sarcocystis falcatula in its intermediate host, the Brown-headed Cowbird (Molothrus ater).

Sporocysts of Sarcocystis falcatula obtained from experimentally infected Virginia opossums (Didelphis virginiana) were inoculated orally to 60 wild-caught Brown-headed Cowbirds (Molothrus ater). Another 30 Brown-headed Cowbirds were not challenged and served as uninfected controls. Two inoculated and one control cowbird were necropsied every 2 weeks and the pectoral and thigh muscles were examined grossly for cyst development.

Viability of Sarcocystis neurona sporocysts and dose titration in gamma-interferon knockout mice.

Gamma-interferon knockout mice have become the model animal used for studies on Sarcocystis neurona. In order to determine the viability of S. neurona sporocysts and to evaluate the course of the disease in these mice, sporocysts were collected from opossums (Didelphis virginiana), processed, and stored for varying periods of time.

Immunoconversion against Sarcocystis neurona in normal and dexamethasone-treated horses challenged with S. neurona sporocysts.

Equine protozoal myeloencephalitis is a common neurologic disease of horses in the Americas usually caused by Sarcocystis neurona. To date, the disease has not been induced in horses using characterized sporocysts from Didelphis virginiana, the definitive host. S.

Equine protozoal myeloencephalitis.

Recent advances in the understanding of the parasite life cycle, epidemiology, clinical signs, diagnosis, treatment, and prevention of EPM are reviewed. The NAHMS Equine '98 study and a controlled retrospective study from The Ohio State University College of Veterinary Medicine identified a number of risk factors associated with development of the disease. The national annual incidence of EPM was 1% or less depending on the primary use of the animals.

Effect of eltenac in horses with induced endotoxaemia.

Ten horses were used in a crossover study to evaluate the effectiveness of eltenac against endotoxaemia. Eltenac (0.5 mg/kg bwt) or saline control was given i.

Patient positioning using detailed three-dimensional surface data for patients undergoing conformal radiation therapy for carcinoma of the prostate: a feasibility study.

Purpose: The increasing complexity of radiotherapy highlights the need for accurate setup. This paper assesses the potential of position corrections, derived from the three-dimensional (3D) surface of the patient, in reducing positioning errors in patients undergoing conformal radiation therapy of the prostate.

Methods And Materials: Twenty patients undergoing conformal radiation therapy for prostate cancer had planning computed tomography (CT) scans and then weekly treatment CT scans over the course of their treatment.

The application of magnetic resonance microimaging to the visible light curing of dental resins. Part 2. Dynamic imaging by the FLASH-MOVIE pulse sequence.

Objectives: To investigate the application of a rapid NMR imaging pulse sequence, FLASH-MOVIE, to the visible light curing of dental restorative materials.

Methods: The light guide was applied at one end of a cylindrical specimen of visible light curing unfilled resin and the light directed along the cylinder. During polymerisation an NMR imaging pulse sequence, FLASH-MOVIE, was run at 15s intervals with a 50 ms repetition time.