Radial dose distribution, dose to water and dose rate constant for monoenergetic photon point sources from 10 keV to 2 MeV:EGS4 Monte Carlo model calculation

A comprehensive set of dose distributions from monoenergetic photon-emitting isotropic point sources in a medium can be used as a reference database for the dosimetry of photon emitter sources in that medium. Data of this type for water over the photon energy range from 15 keV to 2 MeV have been published based on calculations using a one-dimensional photon transport model. The present work, based on a previously published EGS4 Monte Carlo code, updates the classic data set of Berger and provides more extensive calculations than previously available. Air kerma strength per unit photon emission rate from an isotropic point emitter is obtained as a function of energy using published data for mass energy absorption coefficients. The TG-43 dose rate constant for water as a function of energy is calculated for monoenergetic photon emitters as the ratio of dose rate to water at 1 cm to air kerma strength for unit photon emission rate. Results for the radial dose distribution agree well with the data of Berger between 40 and 400 keV. For energies > or =500 keV, a previously undescribed buildup region for the radial dose function is identified. Thickness of the buildup region ranges from 1 mm at 500 keV to 8 mm at 2 MeV. Between 15 and 30 keV, the radial dose function within a few millimeters of the emitter is calculated to be 4%-5% higher than values derived from Berger's data. The maximum dose rate constant for monoenergetic photon emitters occurs at an energy of 60 keV, and has the value 1.355 cGy h(-1)U(-1), where U is the unit of air kerma strength, 1 microGy m2 h(-1). This would correspond to the maximum hypothetical dose rate constant for a brachytherapy photon source emitting photons of energy < or =2 MeV.     

EchoSeed Model 6733 Iodine-125 brachytherapy source: improved dosimetric characterization using the MCNP5 Monte Carlo code

This study primarily aimed to obtain the dosimetric characteristics of the Model 6733 (125)I seed (EchoSeed) with improved precision and accuracy using a more up-to-date Monte-Carlo code and data (MCNP5) compared to previously published results, including an uncertainty analysis. Its secondary aim was to compare the results obtained using the MCNP5, MCNP4c2, and PTRAN codes for simulation of this low-energy photon-emitting source. The EchoSeed geometry and chemical compositions together with a published (125)I spectrum were used to perform dosimetric characterization of this source as per the updated AAPM TG-43 protocol. These simulations were performed in liquid water material in order to obtain the clinically applicable dosimetric parameters for this source model. Dose rate constants in liquid water, derived from MCNP4c2 and MCNP5 simulations, were found to be 0.993 cGyh(-1)?U(-1) (±1.73%) and 0.965 cGyh(-1)?U(-1) (±1.68%), respectively. Overall, the MCNP5 derived radial dose and 2D anisotropy functions results were generally closer to the measured data (within ±4%) than MCNP4c and the published data for PTRAN code (Version 7.43), while the opposite was seen for dose rate constant. The generally improved MCNP5 Monte Carlo simulation may be attributed to a more recent and accurate cross-section library. However, some of the data points in the results obtained from the above-mentioned Monte Carlo codes showed no statistically significant differences. Derived dosimetric characteristics in liquid water are provided for clinical applications of this source model.     

Structure and organization of the histidine-rich protein gene of Plasmodium lophurae

Recombinant cDNA clones representing the carboxy-terminal portion of the histidine-rich protein of Plasmodium lophurae and the 3' untranslated region of the mRNA have been sequenced. Histidine accounts for 78% of the predicted amino acid sequence. The DNA and protein sequences in this region differ significantly from published sequences deduced from cloned genomic DNA of P. lophurae. Sequence data from two independent cDNA clones, comparison of restriction endonuclease sites present in genomic DNA, genomic and cDNA clones, gene titrations, S1 nuclease digestion of cDNA-mRNA hybrids and comparison of predicted and published data for the amino acid composition of the histidine-rich protein all suggest that P. lophurae contains one histidine-rich protein gene and that the sequence of the 3' coding region of this gene has been correctly deduced from the cDNA clones.     

Comparative analysis of multiple genome-scale data sets

The ongoing analyses of published genome-scale data sets is evidence that different approaches are required to completely mine this data. We report the use of novel tools for both visualization and data set comparison to analyze yeast gene-expression (cell cycle and exit from stationary phase/G(0)) and protein-interaction studies. This analysis led to new insights about each data set. For example, G(1)-regulated genes are not co-regulated during exit from stationary phase, indicating that the cells are not synchronized. The tight clustering of other genes during exit from stationary-phase data set further indicates the physiological responses during G(0) exit are separable from cell-cycle events. Comparison of the two data sets showed that ribosomal-protein genes cluster tightly during exit from stationary phase, but are found in three significantly different clusters in the cell-cycle data set. Two protein-interaction data sets were also compared with the gene-expression data. Visual analysis of the complete data sets showed no clear correlation between co-expression of genes and protein interactions, in contrast to published reports examining subsets of the protein-interaction data. Neither two-hybrid study identified a large number of interactions between ribosomal proteins, consistent with recent structural data, indicating that for both data sets, the identification of false-positive interactions may be lower than previously thought.     

HLA class II and TNF genes in African Americans from the Southeastern United States: regional differences in allele frequencies

Knowledge of population major histocompatibility complex gene frequencies is important for construction of organ donor pools and for studies of disease association. Human leukocyte antigen DRB1 (HLA-DRB1), HLA-DQB1, and TNFalpha -308 (G-A) promoter genetic typing was performed in 112 healthy, unrelated African Americans (AAs) from the southeastern United States. Allele frequencies were compared with published frequency data from other AA populations. Our AA population had the highest frequency of HLA- DRB1*09 (6.7%) reported in any AA population. The frequency of the TNF alpha -308A polymorphism was also high (14.4%), when compared with published frequencies in AAs. Significant regional differences in the distribution of most HLA-DRB1 and HLA-DQB1 alleles were observed in all AA populations examined. The AA HLA-DRB1 and -DQB1 frequencies also differed from published Caucasian frequencies. This is the first report describing the distribution of TNF alpha promoter alleles in the Southeastern United States. The high DRB1*09 and TNF alpha -308A allele frequencies of our population most resemble the frequencies of these alleles in certain West African populations. These varying major histocompatibility complex gene frequencies may reflect different regional population structures among AAs in the United States, which may be due to differences in ancestral origins, migration, and racial admixture.     

Glutathione S-transferase T1 status and gastric cancer risk: a meta-analysis of the literature

To clarify the risk of gastric cancer associated with glutathione S-transferase T1 (GSTT1) status, a meta-analysis of published studies was performed. Eligible studies included all reports investigating an association between GSTT1 status and gastric cancer published before October 31, 2005. A qualitative scoring of papers was applied to evaluate the quality of the published data. The principal outcome measure was the odds ratio (OR) for the risk of gastric cancer associated with GSTT1 deletion status using a random effects model. Eighteen case-control studies detailing a possible association between the GSTT1 null genotype and gastric cancer were selected. Combining data from these studies, totalling 2508 cases and 4634 controls, a non-statistically significant OR for gastric cancer risk associated with GSTT1 deficiency emerged [OR = 1.09; 95% confidence interval (CI): 0.97-1.21; I(2) = 0%]. When only high-quality scored studies were considered, a statistically significant increased risk appeared (OR = 1.23; 95% CI: 1.04-1.45; I(2) = 0%), as well as considering only Caucasians (OR = 1.23; 95% CI: 1.03-1.56; I(2) = 0%). By pooling data from seven studies (319 cases and 656 controls) that considered combinations of GSTT1 and GSTM1 genotypes, a statistically significant increased risk for gastric cancer (OR = 1.95, 95% CI: 1.42-2.67; I(2) = 0%) was detected for individuals with deletion mutations in both genes compared with wild-types. In conclusion, this meta-analysis suggests that the GSTT1 null genotype may slightly increase the risk of gastric cancer and that interaction between unfavourable GST genotypes may exist. Greater attention should, therefore, be paid to the design of future studies; the investigation of interactions among multiple genotypes and environmental exposures are justified to clarify GSTT1 null status influence on gastric cancer risk.     

A survey of transforms of the CIE 1931 chromaticity diagram with some new non-linear transforms and histological illustrations of their utility

Surveys are presented of the published data on colour matching, and of the published transforms of the CIE 1931 chromaticity diagram. All transforms are given in the form of standardized equations and tables of coefficients. Both linear and non-linear transforms are considered, although the latter are given special attention. The concept of a uniform chromaticity space (UCS) is discussed, and the published transforms are assessed for uniformity using the colour matching data. 2 series of new, non-linear transforms are presented, both based on 2-dimensional polynomial equations, and both derived using iterative optimization techniques. The 1st series attempts to approximate Farnsworth's (1961) diagram. The 2nd uses Nutting's colour matching points directly. The coefficients of these transforms are tabulated. It was found that increasing the number of coefficients in the 2-dimensional polynomial, beyond 15 each for x and y, does little to increase the uniformity of the resulting transform. The usefulness of UCS's in assessing stain performance is illustrated by examples drawn from the areas of azure B/eosin staining of blood cells and Papanicolaou staining of epithelial cells from the uterine cervix.     

Inhibition of constitutive and inducible cyclooxygenase activity in human platelets and mononuclear cells by NSAIDS and Cox 2 inhibitors

A range of NSAIDs and reported Cox 2 selective compounds were tested in human freshly isolated platelets and LPS-stimulated mononuclear cells to determine their potency and selectivity as inhibitors of constitutive (presumably Cox 1) and inducible (presumably Cox 2) cyclooxygenase respectively. All compounds tested were either equipotent at inhibiting constitutive and inducible cyclooxygenase or were selective for the inducible form. The most selective compound was Dup697 and the least selective, ketoprofen. Several compounds only produced a partial inhibition of constitutive cyclooxygenase as the maximum inhibitor concentration achievable in the assay was limited to 1 mM. With the exception of paracetamol, all compounds were able to produce full inhibition curves against the inducible form. Potency estimates against constitutive Cox compare closely with published data but most compounds were consistently more potent against the inducible isoform than in published data for human cloned, microsomal Cox 2. These data suggest that human mononuclear cells are either exquisitely sensitive to some NSAIDs or they may contain another Cox isoform as yet indistinguishable from Cox 2.     

What types of unintentional injuries kill our children? Do infants die of the same types of injuries? A systematic review

The objective of this study was to review mortality from external causes (accidental injury) in children and adolescents in systematically selected journals. This was a systematic review of the literature on mortality from accidental injury in children and adolescents. We searched the PubMed, Latin-American and Caribbean Health Sciences and Excerpta Medica databases for articles published between July of 2001 and June of 2011. National data from official agencies, retrieved by manual searches, were also reviewed. We reviewed 15 journal articles, the 2011 edition of a National Safety Council publication and 2010 statistical data from the Brazilian National Ministry of Health Mortality Database. Most published data were related to high-income countries. Mortality from accidental injury was highest among children less than 1 year of age. Accidental threats to breathing (non-drowning threats) constituted the leading cause of death among this age group in the published articles. Across the pediatric age group in the surveyed studies, traffic accidents were the leading cause of death, followed by accidental drowning and submersion. Traffic accidents constitute the leading external cause of accidental death among children in the countries under study. However, infants were vulnerable to external causes, particularly to accidental non-drowning threats to breathing, and this age group had the highest mortality rates for external causes. Actions to reduce such events are suggested. Further studies investigating the occurrence of accidental deaths in low-income countries are needed to improve the understanding of these preventable events.     

Gene frequencies of Gc and PGM subtypes

Allele frequencies are presented for subtypes of phosphoglucomutase locus 1 and the group-specific component (Gc) in samples from a number of human populations. Compared with each other and with published data, continental samples are very similar in gene frequency to their reported distributions in the literature, but the small island populations are much more variable.     

Erratum: Genetic and biochemical analyses of Israeli osteogenesis imperfecta patients

During the rendering of the .pdf version of this article, some data in Table 1 were removed. Please find the proper Table 1 published in the online version of the article. The original article to which this Erratum refers was published in Human Mutation 23:399–400 Human Mutation(2004) 23(2) 399–400     

A summary of cytogenetic studies on 534 cases of chronic myelocytic leukemia in Japan

Cytogenetic and clinical data on 534 patients with chronic myelocytic leukemia (CML) were collected from 10 institutions in Japan. The results of the analysis of the data were in substantial accord with those of the First International Workshop on Chromosomes in Leukemia and other published data, but certain differences were noted in the frequency of Philadelphia chromosome (Ph¹)-negative cases, unusual and complex Ph¹ translocations, and additional chromosome changes. Some of the findings are discussed with respect to the origin of unusual and complex Ph¹ translocations, the relationship between chromosome abnormalities and survival, and geographic differences in chromosome abnormalities.     

Cryptic translocation identification in human and mouse using several telomeric multiplex fish (TM-FISH) strategies

Experimental data published in recent years showed that up to 10% of all cases of mild to severe idiopathic mental retardation may result from small rearrangements of the subtelomeric regions of human chromosomes. To detect such cryptic translocations, we developed a "telomeric" multiplex fluorescence in situ hybridization (M-FISH) assay, using a set of previously published and commercially available subtelomeric probes. This set of probes includes 41 cosmid/PAC/P1 clones located from less than 100 kilobases to approximately 1 megabase from the end of the chromosomes. Similarly, a published mouse probe set, comprised of BACs hybridizing to the closest known marker toward the centromere and telomere of each mouse chromosome, was used to develop a mouse-specific "telomeric" M-FISH. Three different combinatorial labeling strategies were used to simultaneously detect all human subtelomeric regions on one slide. The simplest approach uses only three fluors and can be performed in laboratories lacking sophisticated imaging equipment or personnel highly trained in cytogenetics. A standard fluorescence microscope equipped with only three filters is sufficient. Fluor-dUTPs and labeled probes can be custom made, thus dramatically reducing costs. Images can be prepared using imaging software (Adobe Photoshop) and analysis performed by simple visual inspection.     

The nature and metabolism of potentially amyloidogenic carboxyl-terminal fragments of the Alzheimer beta/A4-amyloid precursor protein: some technical notes.

The proteolytic processing and secretion of APP are regulated by protein phosphorylation, especially via protein kinase C and protein phosphatases 1 and/or 2A. Our studies of these regulatory mechanisms have led us to perform extensive experimentation on the metabolism of APP carboxyl-terminal fragments, using as our system either untransfected, undifferentiated rat pheochromocytoma (PC12) cells or APP-baculovirus infected Sf9 cells. We have not assayed APP fragments for biological activity in either system. However, we have made potentially relevant observations regarding APP carboxyl-terminal fragment trafficking. In this note, we review our published and unpublished data in relation to published reports from other laboratories using related systems.     

Linkage analysis of five fibrillar collagen loci in a large French Marfan syndrome family.

Marfan syndrome consists of a group of dominantly inherited disorders of connective tissue with wide clinical variability. Using the candidate gene approach, we have attempted to map the gene defect in a large French Marfan syndrome family with no ocular manifestations. We performed linkage studies with polymorphic probes for five structural procollagen genes. The data obtained exclude linkage of Marfan syndrome to the two major fibrillar collagen (COL1A1, COL1A2, and COL2A1) genes. These results confirm previously published data obtained from smaller pedigrees. A small positive lod score (Z = 0.99, theta = 0.00) was obtained for the COL3A1-COL5A2 gene cluster located on chromosome 2.     

Distribution of alpha1-antitrypsin PI S and PI Z frequencies in countries outside Europe: a meta-analysis

The objective of the present study was to review published surveys on allelic frequencies S and Z in countries outside Europe to evaluate the validity of the reported data. Studies on the topic, published from 1965 to May 2001, were retrieved using MEDLINE and bibliographic reference consultations. The criteria for the selection of the studies were the following: 1) sample size >or=250 individuals; 2) alpha1-antitrypsin phenotype determination performed by means of crossed antigen-antibody, isoelectric focusing in polyacrylamide gels, or polymerase chain reaction (PCR); 3) PI type determination performed without any previous screening procedure; 4) S and Z 95% CI of the reported outcomes within the limits of a calculated coefficient of variation. Forty-three out of 85 studies comply with the established criteria for being analysed. Worldwide maps of geographical distributions of PI S and PI Z frequencies have been designed by the authors by adding the data provided by these 43 selected studies to the 70 reported in a recent European meta-analysis.     

Total scatter factors and tissue maximum ratios for small radiosurgery fields: comparison of diode detectors, a parallel-plate ion chamber, and radiographic film

Two p-type diode detectors, a parallel-plate ion chamber, and radiographic film were used to measure total scatter factors and tissue maximum ratios (TMRs) for a stereotactic radiosurgery system with circular fields ranging from 5 to 50 mm in diameter. One diode has a square detection diagonal of 2.3 mm and the other diode has a circular detection diameter of 1 mm. It is found that the two diodes measured essentially the same total scatter factors for all field sizes. Total scatter factors measured by film are within 3% of diode values. Our results also suggest that the parallel-plate ion chamber could underestimate total scatter factors for fields as large as 15 mm in diameter, although it is recommended for field diameters > or = 12.5 mm. The total scatter factors used in our clinic are combined from data measured with the ion chamber and the 2-mm-diam diode. The combined total scatter factors generally agree with published data. While film overestimates TMRs for the smallest fields at large depths because of energy dependence of the film, the measurements with the 1-mm-diam diode agree with published data measured with thermoluminescent dosimeters. It is demonstrated that the accurate measurements of total scatter factors and TMRs for small fields can be obtained by combining results of the commercially available detectors used in this study.     

Relationship of the recurrent laryngeal nerve to the inferior thyroid artery: A comparison of findings from two systematic reviews

Systematic reviews (SRs) of anatomical studies may include a meta‐analysis (MA) that provides weighted averages as pooled estimates of prevalence. The relationship of the recurrent laryngeal nerve (RLN) to the inferior thyroid artery (ITA) or its branches has been assessed in two published SRs, one without MA of 32 studies (SR1) and the other with MA of 79 studies (SR2). Both SRs reported differences in RLN–ITA patterns (in three categories) by side of the body, but the anterior pattern was less frequent in SR1 vs. SR2. The aim of this review was to explain the differences. The unweighted data from SR1 were found to be more affected (vs. SR2) by a single study with the largest number of RLNs and a low proportion anterior. In a MA using data from SR1, the pooled prevalence estimate for the anterior pattern was substantial (35%) on the right side (vs. 15% on the left) and close to the findings published in SR2. These consistent findings should be relevant to surgeons in attempting to avoid iatrogenic injury to RLNs. Comparison of methods and results from two or more SRs on the same anatomical relationships may be useful in evidence‐based anatomy. Clin. Anat. 30:318–321, 2017. © 2017 Wiley Periodicals, Inc.     

An empirical comparison of meta-analyses of published gene-disease associations versus consortium analyses

PurposeConsortia of investigators currently compile sufficiently large sample sizes to investigate the effects of low-risk susceptibility genetic variants. It is not clear how the results obtained by consortia comparewith those derived from meta-analyses of published studies.MethodsWe performed meta-analyses of published data for 16 genetic polymorphisms investigated by the Breast Cancer Association Consortium, and comparedsample sizes, heterogeneity, and effect sizes. PubMed, Web of Science, and Human Genome Epidemiology Network databases were searched for breast cancer case-control association studies.ResultsWe found that meta-analyses of published data and consortium analyses were based on substantially different data. Published data by nonconsortium teams amounted on average to 26.9% of all available data (range 3.0 –50.0%). Both approaches showed statistically significant decreased breast cancer risks for CASP8 D302H. The meta-analyses of published data demonstrated statistically significant results for five other genes and the consortium analyses for two other genes, but the strength of this evidence, evaluated on the basis of the Venice criteria, was not strong.ConclusionsBecause both approaches identified the same gene out of 16 candidates, the methods can be complimentary. The expense and complexity of consortium-based studies should be considered vis-à-vis the potential methodological limitations of synthesis of published studies.     

A comparison of high-energy accelerator depth dose data

Accurate depth dose information is necessary for the use of high-energy radiotherapy photon beam units. It would be useful, therefore, to have one set of published data available for each different type unit manufactured to which physicists can compare their measured data. Pertinent questions are raised regarding the similarity between accelerators and their central axis depth dose characteristics, the availability of adequate published central axis depth dose data, and the minimum amount of data needed to determine the applicability of published data to a particular machine. Data taken by the Radiological Physics Center (RPC) for 4-10 MV units are analyzed and compared with published data in an attempt to answer these questions.