Collimator design for experimental minibeam radiation therapy.

PURPOSE: To design and optimize a minibeam collimator for minibeam radiation therapy studies using a 250 kVp x-ray machine as a simulated synchrotron source. METHODS: A Philips RT250 orthovoltage x-ray machine was modeled using the EGSnrc/BEAMnrc Monte Carlo software. The resulting machine model was coupled to a model of a minibeam collimator with a beam aperture of 1 mm. Interaperture spacing and collimator thickness were varied to produce a minibeam with the desired peak-to-valley ratio. RESULTS: Proper design of a minibeam collimator with Monte Carlo methods requires detailed knowledge of the x-ray source setup. For a cathode-ray tube source, the beam spot size, target angle, and source shielding all determine the final valley-to-peak dose ratio. CONCLUSIONS: A minibeam collimator setup was created, which can deliver a 30 Gy peak dose minibeam radiation therapy treatment at depths less than 1 cm with a valley-to-peak dose ratio on the order of 23%.

Fourier transform infrared spectromicroscopy and hierarchical cluster analysis of human meningiomas.

Limitations of conventional light microscopy in pathological diagnosis of brain tumors include subjective bias in interpretation and discordance of nomenclature. A study using mid-infrared (IR) spectromicroscopy was undertaken to determine whether meningiomas, a group of brain tumors prone to recurrence, could be identified by the unique spectral 'fingerprints' of their chemical composition. Paired, thin (5-microm) cryosections of snap-frozen human meningioma tumor samples removed at elective surgery were mounted on glass (hematoxylin and eosin-stained tissue section) and infrared (unstained tissue section) reflectance slides, respectively. Concordance of the tumor-bearing areas identified in the stained section by a pathologist with the unstained IR tissue section was ensured using a novel digital grid and tumor-mapping system developed in our laboratory. Compared with the normal control, tumor samples from four meningioma patients revealed a marked decrease in bands associated with unsaturated fatty acids, particularly in the bands at 3010, 2920, 2850, and 1735 cm(-1). Spectral datasets were subjected to hierarchical cluster analyses (HCA) using Ward's algorithm for comparison and grouping of similar data groups, and were converted into color-coded digital maps for matching spectra with their respective clusters. False color images of 5 and 6 clusters obtained by HCA identified dominant clusters corresponding to tumor tissue. Corroboration of these findings in a larger number of meningiomas may allow for more precise identification of these and other types of brain tumors.

Guidelines on the use of intravenous immune globulin for hematologic conditions.

Canada's per capita use of intravenous immune globulin (IVIG) grew by approximately 115% between 1998 and 2006, making Canada one of the world's highest per capita users of IVIG. It is believed that most of this growth is attributable to off-label usage. To help ensure IVIG use is in keeping with an evidence-based approach to the practice of medicine, the National Advisory Committee on Blood and Blood Products of Canada (NAC) and Canadian Blood Services convened a panel of national experts to develop an evidence-based practice guideline on the use of IVIG for hematologic conditions. The mandate of the expert panel was to review evidence regarding use of IVIG for 18 hematologic conditions and formulate recommendations on IVIG use for each. A panel of 13 clinical experts and 1 expert in practice guideline development met to review the evidence and reach consensus on the recommendations for the use of IVIG. The primary sources used by the panel were 3 recent evidence-based reviews. Recommendations were based on interpretation of the available evidence and where evidence was lacking, consensus of expert clinical opinion. A draft of the practice guideline was circulated to hematologists in Canada for feedback. The results of this process were reviewed by the expert panel, and modifications to the draft guideline were made where appropriate. This practice guideline will provide the NAC with a basis for making recommendations to provincial and territorial health ministries regarding IVIG use management. Specific recommendations for routine use of IVIG were made for 7 conditions including acquired red cell aplasia; acquired hypogammaglobulinemia (secondary to malignancy); fetal-neonatal alloimmune thrombocytopenia; hemolytic disease of the newborn; HIV-associated thrombocytopenia; idiopathic thrombocytopenic purpura; and posttransfusion purpura. Intravenous immune globulin was not recommended for use, except under certain life-threatening circumstances, for 8 conditions including acquired hemophilia; acquired von Willebrand disease; autoimmune hemolytic anemia; autoimmune neutropenia; hemolytic transfusion reaction; hemolytic transfusion reaction associated with sickle cell disease; hemolytic uremic syndrome/thrombotic thrombocytopenic purpura; and viral-associated hemophagocytic syndrome. Intravenous immune globulin was not recommended for 2 conditions (aplastic anemia and hematopoietic stem cell transplantation) and was contraindicated for 1 condition (heparin-induced thrombocytopenia). For most hematologic conditions reviewed by the expert panel, routine use of IVIG was not recommended. Development and dissemination of evidence-based guidelines may help to facilitate appropriate use of IVIG.

Adenovirus-mediated CD40 ligand gene-engineered dendritic cells elicit enhanced CD8(+) cytotoxic T-cell activation and antitumor immunity.

CD40L, the ligand for CD40 on dendritic cells (DCs), plays an important role in their activation and is essential for induction of antigen-specific T-cell responses. In the present study, we investigated the efficacy of antitumor immunity induced by vaccination with DCs engineered to express CD40L and pulsed with Mut1 tumor peptide. Our data show that transfection of DCs with recombinant adenovirus AdV-CD40L resulted in activation of DCs with up-regulated expression of proinflammatory cytokines (IL-1beta and IL-12), chemokines (RANTES, IP-10, and MIP-1alpha), and immunologically important cell surface molecules (CD54, CD80, and CD86). Our data also demonstrate that DCs transfected with AdV-CD40L (DC(CD40L)) are able to stimulate enhanced allogeneic T-cell proliferation and Mut1-specific CD8(+) cytotoxic T-cell responses in vitro. Vaccination of mice with Mut1 peptide-pulsed control virus-transfected DC (DC(pLpA)) could only protect mice from challenge of a low dose (0.5 x 10(5) cells per mouse, 8/8 mice), but not a high dose (3 x 10(5) cells per mouse, 0/8 mice) of 3LL tumor cells. However, vaccination of Mut1 peptide-pulsed AdV-CD40L-transfected DC(CD40L) induced an augmented antitumor immunity in vivo by complete protection of mice (8/8) from challenge of both low and high doses of 3LL tumor cells. Thus, DCs engineered to express CD40L by adenovirus-mediated CD40 ligand gene transfer may offer a new strategy in production of DC cancer vaccines.

A new approach to concordance in mid-infrared spectromicroscopy mapping of malignant tumors.

Mid-infrared spectromicroscopy studies on biological tissue sections require accurate identification of tumor-bearing areas in histology-stained and infrared-unstained tissue sections. Concordance was achieved as follows: paired stained and unstained thin (5 microm) human brain tumor cryosections mounted on slides were scanned with a Nikon Coolscan 4000 film scanner at 4000 dpi, edited with Adobe Photoshop CS2 software, and both digital images saved. A digital tractile grid, developed in our laboratory, was overlaid onto both images. Boundaries of tumor-containing areas in stained sections were identified by light microscopy, and a digital boundary map constructed. The map was transferred onto the unstained spectromicroscopy tissue image, and finally layered onto the gridded, equisized, spectromicroscope-generated overview image prior to Fourier transform infrared spectromicroscopy. Accurate identification of tumor-bearing areas, normal brain tissue and transitional zones allowed for meaningful interpretation of respective spectral patterns in detecting subtle differences within biochemical profiles. This is the first reported method of a standardized technique for ensuring concordance in mapping of malignant tumors by mid-infrared spectromicroscopy. This technique is applicable to all biological thin tissue sections, and serves to enhance accuracy of concordance between globar- and synchrotron-light generated infrared data with that obtained by conventional light microscopy.

Yogyakarta Pediatric Cancer Registry: an international collaborative project of University Gadjah Mada, University of Saskatchewan, and the Saskatchewan Cancer Agency.

INTRODUCTION: In July 2001, a 'twinning' project was undertaken between University Gadjah Mada, Indonesia, and the Saskatchewan Cancer Agency, Canada to create a computerised Pediatric Cancer Registry at Sardjito Hospital, Yogyakarta city. OBJECTIVES: To analyse information from the Yogyakarta Pediatric Cancer Registry (YPCR) in order to i) determine the prevalence of pediatric cancers in Yogyakarta Special Region and, ii) compare the demographics of pediatric malignancies in the Special Region (population: 3.3 million), with those of the Saskatchewan Cancer Registry in the province of Saskatchewan (population: 1 million). METHODOLOGY: In May 2001, a computer dedicated to the YPCR was installed at Sardjito Hospital. Bilingual (English/Indonesian) data capture forms were developed for data extraction from hospital health records. Data items were then entered into a data base using the Statistical Package For Social Sciences (SPSS) program. Two projects were initiated: i) a prospective study from 2000-2009 of pediatric cancer cases from the YPCR, and ii) a comparison of demographics from both Cancer Registries during the time period 1996-2003. Comparative data were obtained for age, sex, diagnoses, and referral patterns. Results were analysed using the SPSS software program. RESULTS: i) In the 10 year prospective study, 1,124 pediatriccancer cases were accrued in the Yogyakarta Registry, the majority being in the age group 0-5 years. Male:female: 7:1. Leukemias were the most common diagnosis, followed by retinoblastoma and neuroblastoma. The majority of patients (68%) were referred from outside the catchment area of Yogyakarta Special Region. ii) In the 8 year archival comparative analysis, the most striking contrasts were a higher proportion of children with retinoblastoma and negligible numbers of pediatric brain tumors in the Yogyakarta Registry. CONCLUSION: This is the first published report of a computerised pediatric cancer registry in Indonesia. The differences in diagnostic frequencies noted above may, in part, be due to comparisons between the population-based Saskatchewan Cancer Registry versus the hospital-based Yogyakarta Pediatric Cancer Registry. The contrasts in demographics are multifactorial, and require further investigation.

Biomolecular diagnosis of human glioblastoma multiforme using Synchrotron mid-infrared spectromicroscopy.

Glioblastoma multiforme (GBM) is one of the most malignant human tumors, with a uniformly poor outcome. One obstacle in curing malignant brain tumors is the limitation of conventional light microscopy in detecting microscopic residual tumor in biopsy samples from the perimeter of the surgically resected tumor. We further refined the identification of GBM tumor tissue at the sub-cellular level, utilising the technique of Synchrotron, sourced mid-infrared (mid-IR) spectromicroscopy. Paired, thin (5 microm) cryosections of snap-frozen human GBM tumor samples removed at elective surgery were mounted on glass slides (hematoxylin and eosin-stained tissue section) and calcium fluoride (CaF2) windows (unstained tissue section for transmission spectromicroscopy), respectively. Concordance of tumor bearing areas identified in the stained section with the unstained IR tissue section was confirmed by the pathologist of the study. Compared with molecular signatures obtained from normal control brain tissue, unique spectroscopic patterns were detected in GBM tumor samples from 6 patients. The identifying features of GBM were: i) high protein-to-lipid ratios (amide I+II/CH2 symmetric stretch; amide I+II/CH2+CH3 symmetric and asymmetric stretch), and ii) considerable enhancement of the intensities of characteristic peaks at 2,957 and 2,871 cm(-1) representing CH3 asymmetric and symmetric stretch, respectively. Spectral data sets were subjected to Ward's algorithm for assignment to similar groups, and then subjected to hierarchical cluster analysis (HCA) by means of false color digital maps. False color images of 5 clusters obtained by HCA identified dominant clusters corresponding to tumor tissue. Corroboration of these findings in a larger number of GBM may allow for more precise identification of these and other types of brain tumors.

Pain, distress, and adult-child interaction during venipuncture in pediatric oncology: an examination of three types of venous access.

This study examined pain and distress from needles in children undergoing blood sampling as a function of adult-child interaction and type of venous access (i.e., central external venous lines, internalized ports, or peripheral access via venipuncture). Participants were 55 pediatric oncology patients, aged 3-18 years, who were undergoing routine blood work. Pain ratings were obtained using the Faces Pain Scale-Revised (FPS-R) and conversation during the procedure was audio taped for coding using the Child-Adult Medical Procedure Interaction Scale-Revised (CAMPIS-R). Children's ratings of pain using the FPS-R were similar in the port (M=2.57/10, standard deviation [SD]=3.46) and peripheral (M=2.56/10, SD=3.24) groups, despite the fact that most children with internal ports were given a topical anesthetic. Similarly, there were no differences between port and peripheral groups in rates of child coping or distress, or parent and nurse observations of child pain. As would be expected, external line access was not associated with pain or distress, even among very young children, suggesting that they appropriately understood the pain rating scale. Results of the transcribed CAMPIS-R data indicate that the influences in adult-child interaction are bidirectional. Support was found for the well-established positive relationship between child distress and adult reassurance and empathy. Implications for intervention and selection of central venous access devices are discussed.

Clinical and genetic analysis of unclassifiable inherited bone marrow failure syndromes.

OBJECTIVE: Unclassified inherited bone marrow failure syndromes are a heterogeneous group of genetic disorders that represent either new syndromes or atypical clinical courses of known inherited bone marrow failure syndromes. The relative prevalence of the unclassified inherited bone marrow failure syndromes and their characteristics and the clinical and economic challenges that they create have never been studied. METHODS: We analyzed cases of inherited bone marrow failure syndrome in the Canadian Inherited Marrow Failure Registry that were deemed unclassifiable at study entry. RESULTS: From October 2001 to March 2006, 39 of the 162 patients enrolled in the Canadian Inherited Marrow Failure Registry were registered as having unclassified inherited bone marrow failure syndromes. These patients presented at a significantly older age (median: 9 months) than the patients with classified inherited bone marrow failure syndrome (median: 1 month) and had substantial variation in the clinical presentations. The hematologic phenotype, however, was similar to the classified inherited bone marrow failure syndromes and included single- or multiple-lineage cytopenia, severe aplastic anemia, myelodysplasia, and malignancy. Grouping patients according to the affected blood cell lineage(s) and to the presence of associated physical malformations was not always sufficient to characterize a condition, because affected members from several families fit into different phenotypic groups. Compared with the classified inherited bone marrow failure syndromes, the patients with unclassified inherited bone marrow failure syndromes had 3.2 more specific diagnostic tests at 4.5 times higher cost per evaluated patient to attempt to categorize their syndrome. At last follow-up, only 20% of the unclassified inherited bone marrow failure syndromes were ultimately diagnosed with a specific syndrome on the basis of the development of new clinical findings or positive genetic tests. CONCLUSIONS: Unclassified inherited bone marrow failure syndromes are relatively common among the inherited bone marrow failure syndromes and present a major diagnostic and therapeutic dilemma.

Chronic immune thrombocytopenic purpura in children: a survey of the canadian experience.

BACKGROUND: Immune thrombocytopenic purpura (ITP) in children is a common pediatric bleeding disorder with heterogeneous manifestations and a natural history that is not fully understood. To better understand the natural history of chronic ITP and detect response trends and outcomes of therapy, we conducted a 10-year retrospective survey of children from age 1 to 18 years with a diagnosis of chronic ITP. RESULTS: Data on 198 patients from 8 Canadian Pediatric Hematology/Oncology centers were analyzed. The majority of patients were female (58%), and were previously diagnosed with acute (primary) ITP (85%). The age at diagnosis of chronic ITP ranged from 1.1 to 17.2 years with a mean of 8.2+/-4.4 years. Ninety percent of patients received some form of treatment. Untreated patients had a higher mean platelet count at diagnosis of chronic ITP (P=0.009) despite similarities in mean age at first presentation and mean duration of follow-up. Thirty-four (17%) patients underwent splenectomy. Splenectomized patients tended to be significantly older, had a lower mean platelet count at diagnosis of chronic ITP, and had a longer duration of follow-up. CONCLUSIONS: The results from this study are consistent with published reports.

Expression of N-myristoyltransferase in human brain tumors.

N-myristoylation is a process of covalent irreversible protein modification that promotes association of proteins with membranes. Based on our previous findings of elevated N-myristoyltransferase (NMT) activity in colonic epithelial neoplasms that appears at an early stage in colonic carcinogenesis, together with elevated NMT expression in human colorectal and gallbladder carcinomas, we investigated NMT activity and protein expression of NMT1 and NMT2 in human brain tumors and documented elevated NMT activity and higher protein expressions. For the first time, we have demonstrated that NMT has the potential to be used as a marker of human brain tumors. However, further studies with larger number of patients are required to establish its role as a complementary diagnostic tool. This finding has significant implications for further understanding of biological mechanisms involved in tumorigenesis, as well as for diagnosis and therapy of human brain tumors.