bluuebunny/crossref_metadata_2025 huggingface dataset:
Steepest changes of a probability‐based cost function for delineation of mammographic masses: A validation study
Authors: Kinnard Lisa , Lo Shih‐Chung B. , Makariou Erini , Osicka Teresa , Wang Paul , Chouikha Mohamed F. , Freedman Matthew T.
Published: December 2004

Our purpose in this work was to develop an automatic boundary detection method for mammographic masses and to rigorously test this method via statistical analysis. The segmentation method utilized a steepest change analysis technique for determining the mass boundaries based on a composed probability density cost function. Previous investigators have shown that this function can be utilized to determine the border of the mass body. We have further analyzed this method and have discovered that the steepest changes in this function can produce mass delineations that include extended projections. The method was tested on 124 digitized mammograms selected from the University of South Florida's Digital Database for Screening Mammography (DDSM). The segmentation results were validated using overlap, accuracy, sensitivity, and specificity statistics, where the gold standards were manual traces provided by two expert radiologists. We have concluded that the best intensity threshold corresponds to a particular steepest change location within the composed probability density function. We also found that our results are more closely correlated with one expert than with the second expert. These findings were verifiedviaAnalysis of Variance (ANOVA) testing. The ANOVA tests obtainedp‐values ranging fromfor the single observer studies andfor the two observer studies. Results were categorized using three significance levels, i.e.,(extremely significant),(very significant), and(significant), respectively.
The impact of daily shifts on prostate IMRT dose distributions
Authors: Orton Nigel P. , Tomé Wolfgang A.
Published: December 2004

It is becoming common clinical practice to shift prostate patients daily based on transabdominal ultrasound (US) or imaging of implanted fiducial markers. This paper investigates the dosimetric impact of these shifts by looking at five patients shifted using an optically guided 3D US localization system and treated with IMRT. Treatment plans were generated for each patient for the following 3 cases: (1) the initial preplan, which represents the ideal case in which no shifts are necessary; (2) a postplan incorporating each day's actual shifts; and (3) a postplan in which no shifts were made but the internal organs move by the amounts indicated by daily US imaging. Results show that when daily shifts are made, doses to the target, rectal wall, and bladder wall are nearly identical to those in the preplan. Equivalent uniform dose (EUD) and tumor control probability (TCP) for these plans were also the same as for the preplans. When no shifts were made, however, the dose distributions were degraded, and the computed target EUD and TCP were lower for all five patients. The magnitude of these differences varied: for three patients, the TCP was only 1%–2% lower than for the preplan. For the other two patients, however, the EUD was reduced by more than 10%, resulting in TCP reductions of 6% and 11%. These results indicate that for a symmetric beam arrangement and properly chosen margins, shifting the patient each day and treating without recalculating the dose is unlikely to affect local control or the sparing of normal tissues.
Direct analysis of molybdenum target generated x‐ray spectra with a portable device
Authors: Stumbo S. , Bottigli U. , Golosio B. , Oliva P. , Tangaro S.
Published: December 2004

In routine applications, information about the photon flux of x‐ray tubes is obtained from exposure measurements and cataloged spectra. This approach relies mainly on the assumption that the real spectrum is correctly approximated by the cataloged one, once the main characteristics of the tube such as voltage, target material, anode angle, and filters are taken account of. In practice, all this information is not always available. Moreover, x‐ray tubes with the same characteristics may have different spectra. We describe an apparatus that should be useful for quality control in hospitals and for characterizing new radiographic systems. The apparatus analyzes the spectrum generated by an x‐ray mammographic unit. It is based on a commercial CZT produced by AMPTEK Inc. and a set of tungsten collimator disks. The electronics of the CZT are modified so as to obtain a faster response. The signal is digitized using an analog to digital converter with a sampling frequency of up to 20 MHz. The whole signal produced by the x‐ray tube is acquired and analyzed off‐line in order to accurately recognize pile‐up events and reconstruct the emitted spectrum. The energy resolution has been determined using a calibrated x‐ray source. Spectra were validated by comparison of the HVL measured using an ionization chamber.
Evaluation of radiobiological effects in intensity modulated proton therapy: New strategies for inverse treatment planning
Authors: Wilkens Jan J.
Published: December 2004

Currently, treatment planning for intensity modulated proton therapy (IMPT) usually disregards variations of the relative biological effectiveness (RBE). To investigate the potential clinical relevance of a variable RBE for beam scanning techniques, new strategies for the evaluation of radiobiological effects and for the incorporation of the RBE into the inverse planning process are presented. These strategies are based on a fast algorithm for three‐dimensional calculations of the dose averaged linear energy transfer (LET) as a measure of the local radiation quality, and on a simple phenomenological approach for the RBE as a function of dose, LET and tissue type. It was found that the biological effect depended strongly on the type of scanning technique used, mainly due to differences in the LET distributions. New objective functions that account for LET and RBE were integrated into an inverse planning software, which now allows simultaneous multifield optimization of the biological effect in a reasonable time. With these methods, unfavorable RBE effects can be identified and compensated for by direct optimization of the product of RBE and dose, which is demonstrated for several clinical examples. The proposed strategies are therefore valuable tools to evaluate and improve the quality of treatment plans in IMPT.
An algorithm for independent verification of Gamma Knife™ treatment plans
Authors: Beck James , Berndt Anita
Published: December 2004

A formalism for independent treatment verification has been developed for Gamma Knife™ radiosurgery in analogy to the second checks being performed routinely in the field of external beam radiotherapy. A verification algorithm is presented, and evaluated based on its agreement with treatment planning calculations for the first 40 Canadian Gamma Knife™ patients. The algorithm is used to calculate the irradiation time for each shot, and the value of the dose at the maximum dose point in each calculation matrix. Data entry consists of information included on the plan printout, and can be streamlined by using an optional plan import feature. Calculated shot times differed from those generated by the treatment planning software by an average of 0.3%, with a standard deviation of 1.4%. The agreement of dose maxima was comparable with an average of −0.2% and a standard deviation of 1.3%. Consistently accurate comparisons were observed for centrally located lesions treated with a small number of shots. Large discrepancies were almost all associated with dose plans utilizing a large number of collimator plugs, for which the simplifying approximations used by the program are known to break down.
The behavior of several microionization chambers in small intensity modulated radiotherapy fields
Authors: Stasi M. , Baiotto B. , Barboni G. , Scielzo G.
Published: December 2004

The aim of this work is to compare different ion chambers available for dose measurements in small fields used in intensity modulated radiotherapy. Some dosimetric aspects, related to these small radiation fields, i.e., lack of electronic lateral equilibrium and steep dose region, must be evaluated, in order to obtain an accurate technique implementation. Furthermore, the size of the sensitive volume of the chambers compared with the mapping of the beams or segments needs consideration. If the size of the chamber is too large for the flatness of the field, the measurement can deviate from the expected absorbed dose at a point. We propose a comparison of various dosimetric values between different microionization chambers with respect to a smaller dosimeter, such as the diamond detector.
Large efficiency improvements in BEAMnrc using directional bremsstrahlung splitting
Authors: Kawrakow I. , Rogers D. W. O. , Walters B. R. B.
Published: December 2004

The introduction into the BEAMnrc code of a new variance reduction technique, called directional bremsstrahlung splitting (DBS), is described. DBS uses a combination of interaction splitting for bremsstrahlung, annihilation, Compton scattering, pair production and photoabsorption, and Russian Roulette to achieve a much better efficiency of photon beam treatment head simulations compared to the splitting techniques already available in BEAMnrc (selective bremsstrahlung splitting, SBS, and uniform bremsstrahlung splitting, UBS). In a simulated photon beam ( field) photon fluence efficiency in the beam using DBS is over 8 times higher than with optimized SBS and over 20 times higher than with UBS, with a similar improvement in electron fluence efficiency in the beam. Total dose efficiency in a central‐axis depth‐dose curve improves by a factor of 6.4 over SBS at all depths in the phantom. The performance of DBS depends on the details of the accelerator being simulated. At higher energies, the relative improvement in efficiency due to DBS decreases somewhat, but is still a factor of 3.5 improvement over SBS for total dose efficiency using DBS in a simulated photon beam. Increasing the field size of the simulated beam to (broad beam) causes the relative efficiency improvement of DBS to decrease by a factor of but is still up to 7 times more efficient than with SBS.
Comparison of dose calculation algorithms in phantoms with lung equivalent heterogeneities under conditions of lateral electronic disequilibrium
Authors: Carrasco P. , Jornet N. , Duch M. A. , Weber L. , Ginjaume M. , Eudaldo T. , Jurado D. , Ruiz A. , Ribas M.
Published: December 2004

An extensive set of benchmark measurement of PDDs and beam profiles was performed in a heterogeneous layer phantom, including a lung equivalent heterogeneity, by means of several detectors and compared against the predicted dose values by different calculation algorithms in two treatment planning systems. PDDs were measured with TLDs, plane parallel and cylindrical ionization chambers and beam profiles with films. Additionally, Monte Carlo simulations by meansof the PENELOPE code were performed. Four different field sizes (, , , and) and two lung equivalent materials (CIRS, and St. Bartholomew Hospital, London, ) were studied. The performance of four correction‐based algorithms and one based on convolution‐superposition was analyzed. The correction‐based algorithms were the Batho, the Modified Batho, and the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system and the TMS Pencil Beam from the Helax‐TMS (Nucletron) treatment planning system. The convolution‐superposition algorithm was the Collapsed Cone implemented in the Helax‐TMS. The only studied calculation methods that correlated successfully with the measured values with a 2% average inside all media were the Collapsed Cone and the Monte Carlo simulation. The biggest difference between the predicted and the delivered dose in the beam axis was found for the EqTAR algorithm inside the CIRS lung equivalent material in a x‐ray beam. In these conditions, average and maximum difference against the TLD measurements were 32% and 39%, respectively. In the water equivalent part of the phantom every algorithm correctly predicted the dose (within 2%) everywhere except very close to the interfaces where differences up to 24% were found for photon beams. Consistent values were found between the reference detector (ionization chamber in water and TLD in lung) and Monte Carlo simulations, yielding minimal differences . The penumbra broadening effect in low density media was not predicted by any of the correction‐based algorithms, and the only one that matched the experimental values and the Monte Carlo simulations within the estimated uncertainties was the Collapsed Cone Algorithm.
Influence of x‐ray pulse parameters on the image quality for moving objects in digital cardiac imaging
Authors: Guibelalde Eduardo , Vano Eliseo , Vaquero Francisco , González Luciano
Published: December 2004

The image quality of a single frame in a modern cardiac imaging x‐ray facility can be improved by adjusting the automatic pulse exposure parameters. The effects of acquisition rate on patient dose and the detectability of moving objects have been fully described in scientific literature. However, the influence of automatic pulse exposure parameters is still to be determined. Images of a moving wheel (with lead wires) were acquired using an H5000 Philips Integris cardiac x‐ray system. Poly(methylmethacrylate) plastic samples and thick were employed as the build‐up phantom to simulate a patient. The images were obtained using preset clinical parameters for cardiac imaging procedures. The signal detectability and motion blur of a contrast bar at a transversal speed in the range of were evaluated with a cine pulse width of 3, 5, 7, and under automatic mA kV regulation. Two levels of exposure at the image intensifier entrance were included in this study. Signal detectability was analyzed in terms of the signal‐to‐noise ratio (SNR) and the value of /entrance surface dose. The blurring was modeled as a Gaussian‐shaped blurring function, and the motion blur was expressed in terms of the peak full width at half maximum and amplitude (apparent contrast) of the resolution functions. A contrast bar simulating a vessel in motion at the maximum velocities of typical cardiac structures was exposed. Severe loss of image quality occurred at pulse widths . It is also shown that below static nonlinearities, likely caused by the need to use a large focus for cine acquisition, dominate the blurring process.
Reduction of false positives on the rectal tube in computer‐aided detection for CT colonography
Authors: Iordanescu Gheorghe , Summers Ronald M.
Published: December 2004

Purpose: To eliminate false‐positive (FP) polyp detections on the rectal tube (RT) in CT colonography (CTC) computer‐aided detection (CAD). Methods: We use a three‐stage approach to detect the RT: detect the RT shaft, track the tube to the tip and label all the voxels that belong to the RT. We applied our RT detection algorithm on a CTC dataset consisting of 80 datasets (40 patients scanned in both prone and supine positions). Two different types of RTs were present, characterized by differences in shaft/bulb diameters, wall intensities, and shape of tip. Results: The algorithm detected 90% of RT shafts and completely tracked 72% of them. We labeled all the voxels belonging to the completely tracked RTs (72%) and in 11 out of 80 (14%) cases the RT voxels were partially labeled. We obtained a 9.2% reduction of the FPs in the initial polyp candidates' population, and a 7.9% reduction of the FPs generated by our CAD system. None of the true‐positive detections were mislabeled. Conclusions: The algorithm detects the RTs with good accuracy, is robust with respect to the two different types of RT used in our study, and is effective at reducing the number of RT FPs reported by our CAD system.
Incomplete skin representation in digital mammograms
Authors: Burgess Arthur E. , Kang Haejin
Published: December 2004

Flat‐panel digital detector systems have limited dynamic range and saturate at a particular x‐ray exposure. Hence some of the breast edge may not be represented in the displayed image. We developed a model to estimate the amount of skin loss. Model predictions agreed well with phantom measurements. In our database of 884 clinical digital mammograms, 98% had saturated backgrounds. The estimated skin loss exceeded 0.5 mm in 5% of images and 1.0 mm in 0.7% of images. Any skin thickening that is present should still be visualized, so we conclude that any skin‐line loss may not be of clinical significance.
Reproducibility of multi‐slice spiral computed tomography scans:An experimental study
Authors: van Straten Marcel , Venema Henk W. , Hartman Joris , den Heeten Gerard J. , Grimbergen Cornelis A.
Published: December 2004

In multi‐slice spiral computed tomography (CT) images interpolation artifacts are present. The relationship between the x‐ray tube rotation angle and these artifacts is demonstrated. A head phantom was repeatedly scanned with a four‐slice CT scanner at different pitch values. Two scans, made with identical scan parameters, nearly always have different x‐ray tube starting angles. Consequently, artifacts appeared differently and residual artifacts appeared when subtractions were made. We conclude that only if the x‐ray tube starting angle is equal for both scans or if a very low pitch is used, images are highly reproducible.
Determination of projection geometry from quantitative assessment of the distortion of spherical references in single‐view projection radiography
Authors: Schulze Ralf , Bruellmann Dan Dominik , Roeder Felix , d'Hoedt Bernd
Published: December 2004

A method is introduced, inferring the three‐dimensional (3‐D) location from the 2‐D radiographic shadow of an opaque spherical reference body of known radius by considering its elliptical distortion, the 2‐D shadow location and a known source‐to‐receptor distance. Three noncollinear spheres fixed to a rigid object constitute all possible degrees of freedom, i.e., the entire 3‐D imaging geometry. The method may be used (a) to determine the 3‐D imaging geometry from a single 2‐D view and (b) to correct for foreshortening of object distances coplanar with the plane defined by the sphere triplet. Apart from the mathematical background the article describes a small feasibility experiment, performed with four different sphere diameters and a commercial dental ccd‐receptor system (pixel length: ). The mouse‐cursor based image evaluation revealed an average underestimation of the critical depth‐ coordinate decreasing with increasing radius ( for to 2.8% for ). Intraobserver reliability (the standard deviation between three single cursor‐based assessments) ranged between 0% and 8% of the actual true depth. The main source of the input error is associated with the assessment of the amount of elliptical distortion, where subpixel accuracy is demanded. Consequently, software‐based automated image evaluation is required using available methods for pattern recognition and point‐spread correction. Provided sufficient accuracy, the method provides an important tool for foreshortening correction, depth assessment, motion analysis, and 3‐D reconstruction from two or more 2‐D views.
Adaptation of GEANT4 to Monte Carlo dose calculations based on CT data
Authors: Jiang H. , Paganetti H.
Published: December 2004

The GEANT4 Monte Carlo code provides many powerful functions for conducting particle transport simulations with great reliability and flexibility. However, as a general purpose Monte Carlo code, not all the functions were specifically designed and fully optimized for applications in radiation therapy. One of the primary issues is the computational efficiency, which is especially critical when patient CT data have to be imported into the simulation model. In this paper we summarize the relevant aspects of the GEANT4 tracking and geometry algorithms and introduce our work on using the code to conduct dose calculations based on CT data. The emphasis is focused on modifications of the GEANT4 source code to meet the requirements for fast dose calculations. The major features include a quick voxel search algorithm, fast volume optimization, and the dynamic assignment of material density. These features are ready to be used for tracking the primary types of particles employed in radiation therapy such as photons, electrons, and heavy charged particles. Re‐calculation of a proton therapy treatment plan generated by a commercial treatment planning program for a paranasal sinus case is presented as an example.
Dose enhancement close to platinum implants for the 4, 6, and stereotactic radiosurgery
Authors: Cheung Joel Y. C. , Ng Ben K. P. , Yu K. N.
Published: December 2004

Three photon interaction processes, namely, the photoelectric effect, Compton effect, and pair production, can occur when materials with high atomic numbers are irradiated by the high‐ and low‐energy bremsstrahlung photons from a linear accelerator. A dose enhancement, due to the photoelectric effect and pair production, near targets with platinum implants (with a high atomic number) in radiosurgery cannot be predicted by the radiosurgery treatment planning system. In the present work, Monte Carlo simulations using PRESTA EGS4 were employed to investigate the resulting dose enhancements from 4, 6, and energies commonly used in the stereotactic radiosurgery system. Dose enhancements from 32% to 68% were observed close to the platinum implant for the above energies when using a collimator. Comparatively higher dose enhancements were observed when using smaller collimators. It was found that this dose enhancement increased with beam energy but decreased as beam size increased.
Genomic relationships among diploid and hexaploid species of Andropogon (Poaceae)
Authors: Norrmann G , Hanson L , Renvoize S , Leitch I J
Published: December 2004

Andropogon is a pantropical grass genus comprising 100–120 species and found mainly in the grasslands of Africa and the Americas. While the genomic relationships between many Andropogon species have been resolved by studying chromosome behavior in interspecific hybrids, relationships between the North and South American diploids have remained elusive. Further, the genome composition of two hexaploid species (including the important forage grass Andropogon lateralis Nees) has been unclear because of the strong hybridization barriers that exist between species. Consequently, genomic in situ hybridization was applied to shed light on these issues. The results confirmed that (i) both the South American (Andropogon selloanus (Hack.) Hack., Andropogon macrothrix Trin.) and North American (Andropogon gyrans Michx.) diploid species shared a common S genome and (ii) the S genome comprises just one of the three genomes in the hexaploids A. lateralis Nees and Andropogon bicornis L. The evolutionary and taxonomic implications of these findings are discussed.Key words: Andropogon, polyploidy evolution, Poaceae, genomic in situ hybridization, taxonomy.
Chromosomal localization, genomic organization and evolution of the genes encoding human phosphatidylinositol transfer protein membrane-associated (PITPNM) 1, 2 and 3
Authors: Ocaka L. , Spalluto C. , Wilson D.I. , Hunt D.M. , Halford S.
Published: December 2004

Eukaryotic proteins containing a phosphatidylinositol transfer (PITP) domain can be divided into two groups, one consisting of small soluble 35-kDa proteins and the other those that are membrane-associated and show sequence similarities to the Drosophila retinal degeneration B (rdgB) protein. The rdgB protein consists of four domains, an amino terminal PITP domain, a Ca2+-binding domain, a transmembrane domain and a carboxyl terminal domain that interacts with the protein tyrosine kinase PYK2. Three mammalian phosphatidylinositol transfer protein membrane-associated genes (PITPNM1, 2 and 3) with homology to Drosophila rdgB have previously been described and shown to be expressed in the mammalian retina. These findings and the demonstration that the rdgB gene plays a critical role in the invertebrate phototransduction pathway have led to the mammalian genes being considered as candidate genes for human eye diseases. In order to facilitate the analysis of these genes we have used radiation hybrid mapping and fluorescence in situ hybridization to localize the PITPNM2 and 3 genes to human chromosomes 12p24 and 17p13 respectively and hybrid mapping to confirm the localization of PITPNM1 to chromosome 11q13. We have also determined the genomic organization of both the soluble and membrane-associated Drosophila and human PITP domain-containing genes. Phylogenetic analysis indicates that the two groups arose by gene duplication that occurred very early in animal evolution.
New insights into the karyotypic relationships of Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis)
Authors: Chi J. , Fu B. , Nie W. , Wang J. , Graphodatsky A.S. , Yang F.
Published: December 2004

To investigate the karyotypic relationships between Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis), a complete set of Chinese muntjac chromosome-specific painting probes has been assigned to G-banded chromosomes of these three species. Sixteen autosomal probes (i.e. 6–10, 12–22) of the Chinese muntjac each delineated one pair of conserved segments in the forest musk deer and gayal, respectively. The remaining six autosomal probes (1–5, and 11) each delineated two to five pairs of conserved segments. In total, the 22 autosomal painting probes of Chinese muntjac delineated 33 and 34 conserved chromosomal segments in the genomes of forest musk deer and gayal, respectively. The combined analysis of comparative chromosome painting and G-band comparison reveals that most interspecific homologous segments show a high degree of conservation in G-banding patterns. Eleven chromosome fissions and five chromosome fusions differentiate the karyotypes of Chinese muntjac and forest musk deer; twelve chromosome fissions and six fusions are required to convert the Chinese muntjac karyotype to that of gayal; one chromosome fission and one fusion separate the forest musk deer and gayal. The musk deer has retained a highly conserved karyotype that closely resembles the proposed ancestral pecoran karyotype but shares none of the rearrangements characteristic for the Cervidae and Bovidae. Our results substantiate that chromosomes 1–5 and 11 of Chinese muntjac originated through exclusive centromere-to-telomere fusions of ancestral acrocentric chromosomes.
Genotype/phenotype correlation in a patient with partial monosomy 15 and partial trisomy 14
Authors: Volleth M. , Stumm M. , Bürger J. , Muschke P. , Wieacker P.
Published: December 2004

We report on a girl with severe mental and psychomotor retardation caused by an unusual, unbalanced translocation t(14;15) of maternal origin. The unbalanced translocation in the patient resulted in trisomy 14pter→q13 and monosomy 15pter→q11.2. In addition to common features described in other patients with small proximal trisomies of chromosome 14, our patient presented with hypopigmented skin with light hair and eye color and severe speech impairment. Therefore the phenotype of the girl shows few similarities to that of Angelman syndrome patients, although the breakpoint in chromosome 15 in our patient was found to be proximal to the PWS/AS region.
Genetic evidence of a strong functional constraint of neurotrypsin during primate evolution
Authors: Xu H.L. , Su B.
Published: December 2004

Neurotrypsin is one of the extra-cellular serine proteases that are predominantly expressed in the brain and involved in neuronal development and function. Mutations in humans are associated with autosomal recessive non-syndromic mental retardation (MR). We studied the molecular evolution of neurotrypsin by sequencing the coding region of neurotrypsin in 11 representative non-human primate species covering great apes, lesser apes, Old World monkeys and New World monkeys. Our results demonstrated a strong functional constraint of neurotrypsin that was caused by strong purifying selection during primate evolution, an implication of an essential functional role of neurotrypsin in primate cognition. Further analysis indicated that the purifying selection was in fact acting on the SRCR domains of neurotrypsin, which mediate the binding activity of neurotrypsin to cell surface or extra-cellular proteins. In addition, by comparing primates with three other mammalian orders, we demonstrated that the absence of the first copy of the SRCR domain (exon 2 and 3) in mouse and rat was due to the deletion of this segment in the murine lineage.
First small supernumerary ring chromosome carrying 10q euchromatin in a patient with mild phenotype characterized by molecular cytogenetic techniques and review of the literature
Authors: Trimborn M. , Grueters A. , Neitzel H. , Tönnies H.
Published: December 2004

We report the identification and characterization of the first supernumerary ring chromosome 10 containing a considerable proportion of 10q euchromatin by microdissection and reverse painting in a female patient presenting with short stature. Fluorescence in situ hybridization studies showed that the marker chromosome originates from chromosome 10 and includes the euchromatic bands p11.2 and q11.2. The supernumerary marker chromosome 10 was found in 14% of the peripheral blood lymphocytes analyzed. This constitutional mosaic could be confirmed in oral mucosa cells as a second cell system (16%) by interphase FISH using an alphoid centromeric probe for chromosome 10. Parental karyotypes were normal, uniparental disomy for the normal chromosomes 10 could be excluded by microsatellite analysis. The karyotype of the patient detected in peripheral blood cells can be described as mos 47,XX,+mar.rev ish r(10)(p11.2q11.2)(wcp10+,cep10+)/46,XX.
Chromosome evolution of MMU16 and RNO11: conserved synteny associated with gene order rearrangements explicable by intrachromosomal recombinations and neocentromere emergence
Authors: Szpirer C. , Rivière M. , VanVooren P. , Moisan M.-P. , Haller O. , Szpirer J.
Published: December 2004

Comparative mapping between the rat and mouse genomes has shown that some chromosomes are entirely or almost entirely conserved with respect to gene content. Such is the case of rat chromosome 11 (RNO11) and mouse chromosome 16 (MMU16). We determined to what extent such an extensive conservation of synteny is associated with a conserved gene order. Therefore, we regionally localized several genes on RNO11. The comparison of the gene map of RNO11 and MMU16 unambiguously shows that the gene order has not been conserved in the Murinae lineage, thereby implying the occurrence of intrachromosomal evolutionary rearrangements. The transition from one chromosome configuration to the other one can be explained either by two intrachromosomal recombinations or by a single intrachromosomal recombination accompanied by neocentromere emergence.
Comparative sequence analysis and radiation hybrid mapping of two epidermal type II keratin genes in the dog: keratin 1 and keratin 2e
Authors: Credille K.M. , Guyon R. , André C. , Murphy K. , Tucker K. , Barnhart K.F. , Dunstan R.W.
Published: December 2004

In order to extend knowledge of the process of cornification across species and to be better able to recognize inborn errors in keratin synthesis in the dog, we describe the organization and chromosome mapping of canine KRT1 and KRT2E and compare these results to human and murine sequence data. The coding regions of KRT1 and KRT2E are 1,860 bp and 1,902 bp respectively, distributed over nine exons. Both genes are localized on the canine radiation hybrid map to chromosome 27 in the type II keratin gene cluster close to polymorphic markers. These genes are highly conserved across species and based on both genomic and amino acid sequences, canine KRT1 and KRT2E share greater homology with humans than with mice.
Sequencing and mapping hemoglobin gene clusters in the Australian model dasyurid marsupial Sminthopsis macroura
Authors: De Leo A.A. , Wheeler D. , Lefevre C. , Cheng J.-F. , Hope R. , Kuliwaba J. , Nicholas K.R. , Westerman M. , Graves J.A.M.
Published: December 2004

Comparing globin genes and their flanking sequences across many species has allowed globin gene evolution to be reconstructed in great detail. Marsupial globin sequences have proved to be of exceptional significance. A previous finding of a β(beta)-like ω(omega) gene in the α(alpha) cluster in the tammar wallaby suggested that the α and β cluster evolved via genome duplication and loss rather than tandem duplication. To confirm and extend this important finding we isolated and sequenced BACs containing the α and β loci from the distantly related Australian marsupial Sminthopsis macroura. We report that the α gene lies in the same BAC as the β-like ω gene, implying that the α-ω juxtaposition is likely to be conserved in all marsupials. The LUC7L gene was found 3′ of the S. macroura α locus, a gene order shared with humans but not mouse, chicken or fugu. Sequencing a BAC contig that contained the S. macroura β globin and Ε globin loci showed that the globin cluster is flanked by olfactory genes, demonstrating a gene arrangement conserved for over 180 MY. Analysis of the region 5′ to the S. macroura epsilon (Ε) globin gene revealed a region similar to the eutherian LCR, containing sequences and potential transcription factor binding sites with homology to eutherian hypersensitive sites 1 to 5. FISH mapping of BACs containing S. macroura α and β globin genes located the β globin cluster on chromosome 3q and the α locus close to the centromere on 1q, resolving contradictory map locations obtained by previous radioactive in situ hybridization.
Freemartinism in river buffalo: clinical and cytogenetic observations
Authors: Iannuzzi L. , Di Meo G.P. , Perucatti A. , Ciotola F. , Incarnato D. , Di Palo R. , Peretti V. , Campanile G. , Zicarelli L.
Published: December 2004

During the last five years forty phenotypic female river buffalos with reproductive problems and two phenotypic male co-twins of females, raised in the provinces of Caserta and Salerno (southern Italy) underwent cytogenetic investigation. Of the 42 animals studied, 10 freemartins (8 females and 2 males) were found with variable percentages of male and female blood cells, the majority however showing similar percentages of both. Of the eight females, six showed normal body conformation, vagina and clitoris, while two showed some male traits (tight pelvis). The two males were apparently normal with only a reduced size of one testicle in one animal. Clinical observations performed in the internal reproductive organs of the female carriers by both rectal palpation (5 females) and direct observation after mating (3 females) revealed serious damages varying from complete lack of internal sex adducts (closed vagina) to hypoplasia of Müllerian ducts and absence (or atrophy) of ovaries. All freemartin females were sterile. To our knowledge, this is the first detailed description of freemartinism in river buffalo by combining clinical and cytogenetic analyses.
Renal Cell Carcinoma: The Experience of Kuwait Cancer Control Center, Kuwait
Authors: Thotathil Z.S. , Varghese A. , Ragheb A.
Published: December 2004

Objectives: This retrospective study was undertaken to analyze the profile of patients presenting with renal cell carcinoma (RCC) and treatment outcomes. Subjects and Methods: Records of 49 patients (36 male, 16 female, 21–75 years) treated at the Kuwait Cancer Control Center, Kuwait for RCC during the period 1993–1998 were analyzed. Forty-one patients had a nephrectomy, 18 postoperative radiotherapy and 1 patient also received adjuvant immunotherapy with interferon. Patients with metastatic disease were treated with a variety of agents including interferon, chemotherapy (vinblastine) or a hormonal agent (megestrol acetate). Data analysis was performed using SPSS statistical software package. Overall survival and disease-free survival were calculated using the Kaplan-Meier method. Results: Twenty-nine patients presented with symptoms classically associated with RCC. Metastases at diagnosis were seen in 9 patients (18%), with lung being the most frequent site. The commonest tumor subtype was clear cell carcinoma (32.6%). Thirty-nine patients (80%) achieved a complete response to treatment and relapse was documented in 10 patients (26%). The majority of failures were distant, with lung metastases being the most common. Response to salvage treatment was poor. Overall survival was 83% at 2 years. The disease-free survival was 68 and 45% at 2 and 5 years, respectively. Conclusions: Although many patients presented with advanced local disease, a majority achieved complete response after radical surgery with or without postoperative radiation therapy. Salvage of metastatic disease proved difficult with interferon, chemotherapy.
Effect of Self-Medication with Antimalarial Drugs on Malaria Infection in Pregnant Women in South-Western Nigeria
Authors: Akanbi O.M. , Odaibo A.B. , Afolabi K.A. , Ademowo O.G.
Published: December 2004

Objective: To determine the effect of self-medication with chloroquine and pyrimethamine on malaria infection and anaemia during pregnancy. Subjects and Methods: The study involved 210 women who attended Ade Oyo Maternity State Hospital, Ibadan, Nigeria. Of these, 156 were pregnant women while 54 were not pregnant (controls). Of the pregnant women, 66 were primigravidae, while 90 were multigravidae. History of treatment of malaria with antimalarial drugs was obtained from the subjects. Gravidity and gestation period were also documented. Two millilitres of blood was withdrawn from each subject, for haematological parameters. Thin and thick films were prepared for malaria parasite identification and quantification. Results: Of the primigravidae and multigravidae 68 and 16.4%, respectively, had taken antimalarial drugs prior to booking. Among primigravidae, only18% of those with drugs compared with 32% without drugs were malaria-positive. The parasite density was significantly lower among those who took antimalarial drugs than among those who did not (976 ± 60 versus 2,421 ± 78, p < 0.05). Similarly, among multigravidae, only 16.4% of those who took antimalarial drugs compared with 34% of those who were not malaria-positive. The parasite density was also significantly lower in multigravidae with drugs than among those without drugs (350 ± 45 versus 1,000 ± 65, p < 0.05). The prevalence of anaemia (packed cell volume, PCV <33) was high, 89% in primigravidae and 70% in multigravidae. Severe anaemia (PCV <21) was more common in malaria-positive primigravidae and multigravidae than in malaria-negative women. Conclusion: The findings indicate that self-medication with chloroquine and pyrimethamine at booking was able to reduce the prevalence of malaria and anaemia in pregnancy.
Differences in the Location and Multiplicity of Mandibular Fractures in Kuwait, Canada and Finland during the 1990s
Authors: Oikarinen Kyosti , Thalib Lukman , Sàndor George K.B. , Schutz Petr , Clokie Cameron M.L. , Safar Slavek , Meisami Tina , Perheentupa Ulla
Published: December 2004

Objective: To compare the location and multiplicity of mandibular fractures in Kuwait, Canada and Finland during the 1990s. Subjects and Methods: Data were collected from several hospitals in Kuwait (1991–2000), Toronto General Hospital in Canada (1995–2000) and Oulu University Hospital in Finland (1990–1999). The data were analyzed statistically using chi-square test, ANOVA, t test and logistic regression. Results: Condylar fractures were more common in Finnish patients (41%) than Canadian (35%) or Kuwaiti patients (21%). Condylar fractures caused by falls were about 3.4 times more common in Kuwait and Finland compared to Canada. In Finland the risk of road traffic accidents caused by condylar fracture was about 4 times higher than those caused by other etiologies. In Canada male gender was about 2 times higher for the condylar fracture than female gender. Female patients often had more multiple injuries than men in all three countries and multiple fractures were observed especially in traumas caused by falling. Conclusion: Differences in location and multiplicity of mandibular fractures are due to differences in etiologies and demographic patterns.
Differences in Physician Compliance with Guideline on Lipid Profile Determination within 24 h after Acute Myocardial Infarction
Authors: Al Aqeel A. , Mojiminiyi O.A. , Al Dashti R. , Al Ozairi E.S.S.
Published: December 2004

Objective: To evaluate the American College of Cardiology/American Heart Association guidelines on blood lipid testing within 24 h of the onset of chest pain in patients with myocardial infarction. Subjects and Methods: This is a cross-sectional observational study on 83 patients (77 male, 6 female) admitted into the Coronary Care Units of the Al-Amiri and Mubarak Al-Kabeer Hospitals, Kuwait with myocardial infarction. The lipid profiles were obtained within 24 h of the onset of chest pain. Twenty patients were on treatment with statins prior to admission. Diagnosis of myocardial infarction in all patients was based on standard criteria. Total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, and triglycerides (Tg) were measured and low-density lipoprotein (LDL) cholesterol was calculated. Results: Twenty-three patients had normal cardiac markers on admission but later developed increased serum markers and ECG changes of acute myocardial infarction. Mean (95% confidence interval) TC, HDL, Tg and LDL were 5.1 (4.8–5.4); 0.93 (0.88–0.98); 1.85 (1.56–2.14), and 3.39 (3.13–3.65) mmol/l, respectively. 70% of the patients had normal or only mild elevations of LDL with low HDL and poor HDL:TC ratio (<20%). Thirty-eight patients had low HDL (<0.9 mmol/l) and only 22 (27%) patients met the National Cholesterol Education Program guideline of target LDL <2.6 mmol/l. Fifty-six patients were classified as having the metabolic syndrome according to the criteria of the WHO. Conclusion: The findings indicate that HDL appears to be the main lipid risk factor in patients presenting with AMI in Kuwait, therefore primary prevention strategies should focus on treatment modalities that increase HDL. We recommend that the lipid profile should be done within 24 h of admission and lipid-lowering therapy initiated as part of secondary prevention strategy.
Role of Magnetic Resonance Imaging in the Assessment of Perianal Fistulas
Authors: Al-Khawari H.A. , Gupta R. , Sinan T.S. , Prakash B. , Al-Amer A. , Al-Bolushi S.
Published: December 2004

Objective: This study was carried out to evaluate the role of magnetic resonance imaging (MRI) in preoperative assessment of fistula-in-ano. Subjects and Methods: Twenty-six patients (21 male and 5 female, age 19–65 years) were prospectively studied from July 1999 to December 2001 using a 1.0-tesla superconducting magnet. T1-weighted fast spin echo (T1W FSE) images before and after gadolinium injection and fat suppressed T2-weighted fast spin echo (T2W FSE) images were obtained in transverse and coronal planes. MRI findings were correlated with surgical findings. Results: Twenty-one of the 26 patients demonstrated active fistulas. The MRI findings were in accordance with the examination findings under anesthesia and/or surgery in 15 of 16 cases. Both coronal and transverse planes were useful in assessing the location and direction of tracts and abscesses. Both contrast-enhanced T1W FSE and fat-suppressed T2W FSE images were useful in assessing the activity of lesions and the course of tracts. Conclusion: MRI showed accurate correlation with surgical findings and aided in preoperative management and planning for surgery.
Rupture of Splenic Artery Aneurysm during Labor: A Case Report of Maternal and Fetal Survival
Authors: Al Asfar Fahad , Saber Mohamed , Dhar Piyaray M. , Al Awadhi Nema
Published: December 2004

Objective: To report a case of splenic artery aneurysm that ruptured during labor with both maternal and fetal survival. Clinical Presentation and Intervention: A 33-year-old primigravida at 42 weeks of gestation was admitted to Adan Hospital for induction of labor. Three days after induction, the patient suddenly collapsed and was found to be hypotensive. Abruptio placentae was mistakenly diagnosed, despite the absence of vaginal bleeding, and the patient was immediately taken to the operating room for emergency cesarean section. A female infant was delivered without any evidence of abruptio placentae but with 2,000 ml blood noted in the abdominal cavity. A vertical midline incision was performed and a ruptured splenic artery aneurysm was found. Proximal ligation of the splenic artery was performed followed by splenectomy. Both mother and newborn did well and were discharged on the 7th postoperative day. Conclusion: This case illustrates the need to consider ruptured splenic artery aneurysm as part of differential diagnosis of hemoperitoneum in pregnant women. Immediate surgical intervention is needed to ensure survival of both mother and fetus.
Listeria monocytogenes Meningitis in an Immunocompetent Adult Patient
Authors: Jamal W.Y. , Al-Shomari S. , Boland F. , Rotimi V.O.
Published: December 2004

Objective: To report an interesting case of meningitis caused by Listeria monocytogenes in an immunocompetent adult. Patient and Methods: A previously healthy 25-year-old man presented with typical clinical features of meningitis. Cerebrospinal fluid (CSF) was obtained on the day of admission for biochemical and microbiological investigations. In addition, blood was also taken for culture and hematological studies. Antibiotic susceptibility test was performed using the Etest method. Microscopic examination of the CSF showed pleocytosis, which was predominantly lymphocytic, while the biochemical investigation revealed raised concentrations of protein and lactic acid as well as decreased glucose concentration. A 24-hour culture yielded pure growth of gram-positive bacilli identified by standard methods as L. monocytogenes. It was susceptible to ampicillin and trimethoprim-sulfamethoxazole. The patient was treated with intravenous ampicillin combined with gentamicin and made a complete recovery. Conclusion: This presentation describes an unusual case of meningitis caused by L. monocytogenes in a previously healthy young adult with no risk factor. Only a few similar cases have been reported in the literature.
Clear Cell Adenocarcinoma of the Rectum
Authors: Mallik A.A. , Katchy K.C.
Published: December 2004

Objective: To document the first case of clear cell adenocarcinoma of the rectum (a rare entity) in Kuwait. Clinical Presentation and Intervention: A 36-year-old female presented with a 1-year history of constipation and bleeding per rectum. Colonoscopy revealed an ulcerated mass 2 cm above the anal verge. After multiple biopsies an abdomino-perineal resection was performed for the rectal mass. Gross examination of the resected specimen revealed an anorectal mass measuring 5 cm in its long axis. Histopathological examination showed the tumor to be composed of lobules of mostly clear polygonal cells with round vesicular nuclei. Glandular formation was occasional. The tumor was rich in glycogen, focally displayed luminal mucin, and was associated with regional lymph node metastasis. Conclusion: This report illustrates a case of intestinal clear cell adenocarcinoma with lymph node metastasis that suggested a poor prognosis.