bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of a novel collimator for high‐sensitivity brain SPECT
Authors: Fakhri Georges El , Ouyang Jinsong , Zimmerman Robert E. , Fischman Alan J. , Kijewski Marie Foley
Published: January 2006

We assessed improvements in performance in detection and estimation tasks due to a novel brain single photon computed tomography collimator. Data were acquired on the scanner using both new and standard collimators. The new variable focusing collimator samples the projections unequally, with central regions more heavily represented, to compensate for attenuation of counts from central brain structures. Furthermore, it utilizes more of the cylindrical crystal surface. Two phantom studies were performed. The first phantom was a 21‐cm‐diameter cylindrical background containing nine spheres ranging from 0.5 to in volume. sphere to background activity ratio was 10:1. Twenty‐nine 10‐min datasets were acquired with each collimator. The second phantom was the Radiology Support Devices (Long Beach, CA) striatal phantom with striatal‐background ratios of 10:1 on the left and 5:1 on the right. Twenty‐nine 4‐min datasets were acquired with each collimator. Perfusion imaging using ‐HMPAO was also performed in three healthy volunteers using both collimators under identical simulations. Projections were reconstructed by filtered backprojection with an unwindowed ramp filter. The nonprewhitening matched filter signal‐to‐noise ratio (NPW‐SNR) was computed as a surrogate for human performance in detecting spherical lesions. Sphere activity concentration, radius, and location coordinates were simultaneously estimated by fitting images to an assumed model using an iterative nonlinear algorithm. Resolution recovery was implicit in the estimation procedure, as the point spread function was incorporated into the model. NPW‐SNR for sphere detection was 1.5 to 2 times greater with the new collimator; for the striatal phantom the improvement in SNR was 54%. The SNR for estimating sphere activity concentration improved by 46 to for spheres located more than from the phantom center. Images acquired with the standard collimator were too noisy in the central regions to allow estimation of sphere activity. In ‐HMPAO human studies, SNR was improved by 21 to in the cortex, 66% in the basal ganglia, and 74% in the thalamus. The new collimator leads to substantially improved detection and estimation performance throughout the brain. The higher sensitivity will be particularly important for dynamic imaging.
The stability of mechanical calibration for a kV cone beam computed tomography system integrated with linear acceleratora)
Authors: Sharpe Michael B. , Moseley Douglas J. , Purdie Thomas G. , Islam Mohammad , Siewerdsen Jeffrey H. , Jaffray David A.
Published: January 2006

The geometric accuracy and precision of an image‐guided treatment system were assessed. Image guidance is performed using an x‐ray volume imaging (XVI) system integrated with a linear accelerator and treatment planning system. Using an amorphous silicon detector and x‐ray tube, volumetric computed tomography images are reconstructed from kilovoltage radiographs by filtered backprojection. Image fusion and assessment of geometric targeting are supported by the treatment planning system. To assess the limiting accuracy and precision of image‐guided treatment delivery, a rigid spherical target embedded in an opaque phantom was subjected to 21 treatment sessions over a three‐month period. For each session, a volumetric data set was acquired and loaded directly into an active treatment planning session. Image fusion was used to ascertain the couch correction required to position the target at the prescribed iso‐center. Corrections were validated independently using megavoltage electronic portal imaging to record the target position with respect to symmetric treatment beam apertures. An initial calibration cycle followed by repeated image‐guidance sessions demonstrated the XVI system could be used to relocate an unambiguous object to within less than of the prescribed location. Treatment could then proceed within the mechanical accuracy and precision of the delivery system. The calibration procedure maintained excellent spatial resolution and delivery precision over the duration of this study, while the linear accelerator was in routine clinical use. Based on these results, the mechanical accuracy and precision of the system are ideal for supporting high‐precision localization and treatment of soft‐tissue targets.
A high‐speed scintillation‐based electronic portal imaging device to quantitatively characterize IMRT delivery
Authors: Ranade Manisha K. , Lynch Bart D. , Li Jonathan G. , Dempsey James F.
Published: January 2006

We have developed an electronic portal imaging device (EPID) employing a fast scintillator and a high‐speed camera. The device is designed to accurately and independently characterize the fluence delivered by a linear accelerator during intensity modulated radiation therapy (IMRT) with either step‐and‐shoot or dynamic multileaf collimator (MLC) delivery. Our aim is to accurately obtain the beam shape and fluence of all segments delivered during IMRT, in order to study the nature of discrepancies between the plan and the delivered doses. A commercial high‐speed camera was combined with a terbium‐doped gadolinium‐oxy‐sulfide scintillator to form an EPID for the unaliased capture of two‐dimensional fluence distributions of each beam in an IMRT delivery. The high speed EPID was synchronized to the accelerator pulse‐forming network and gated to capture every possible pulse emitted from the accelerator, with an approximate frame rate of (fps). A 62‐segment beam from a head‐and‐neck IMRT treatment plan requiring to deliver was recorded with our high speed EPID producing approximately of imaging data. The EPID data were compared with the MLC instruction files and the MLC controller log files. The frames were binned to provide a frame rate of with a signal‐to‐noise ratio that was sufficient to resolve leaf positions and segment fluence. The fractional fluence from the log files and EPID data agreed well. An ambiguity in the motion of the MLC during beam on was resolved. The log files reported leaf motions at the end of 33 of the 42 segments, while the EPID observed leaf motions in only 7 of the 42 segments. The static IMRT segment shapes observed by the high speed EPID were in good agreement with the shapes reported in the log files. The leaf motions observed during beam‐on for step‐and‐shoot delivery were not temporally resolved by the log files.
Technical and dosimetric aspects of respiratory gating using a pressure‐sensor motion monitoring system
Authors: Li X. Allen , Stepaniak Christopher , Gore Elizabeth
Published: January 2006

This work introduces a gating technique that uses 4DCT to determine gating parameters and to plan gated treatment, and employs a Siemens linear accelerator to deliver the gated treatment. Because of technology incompatibility, the 4DCT scanner (LightSpeed, GE) and the Siemens accelerator require two different motion‐monitoring systems. The motion monitoring system (AZ‐773V, Anzai Med.) used for the gated delivery utilizes a pressure sensor to detect the external respiratory motion (pressure change) in real time. Another system (RPM, Varian) used for the 4DCT scanner (LightSpeed, GE) is based on an infrared camera to detect motion of external markers. These two motion monitoring systems (RPM and Anzai systems) were found to correlate well with each other. The depth doses and profile measured for gated delivery (with a duty cycle of 25% or 50%) were found to agree within 1.0% with those measured for ungated delivery, indicating that gating did not significantly alter beam characteristics. The measurement verified also that the MU linearity and beam output remained unchanged (within 0.3%). A practical method of using 4DCT to plan a gated treatment was developed. The duty cycle for either phase or amplitude gating can be determined based on 4DCT with consideration of set‐up error and delivery efficiency. The close‐loop measurement involving the entire gating process (imaging, planning, and delivery) showed that the measured isodose distributions agreed with those intended, validating the accuracy and reliability of the gating technique. Based these observations, we conclude that the gating technique introduced in this work, integrating Siemens linear accelerator and Anzai pressure sensor device with GE/Varian RPM 4DCT, is reliable and effective, and it can be used clinically to account for respiratory motion during radiation therapy.
Strategies for inner volume 3D fast spin echo magnetic resonance imaging using nonselective refocusing radio frequency pulsesa)
Authors: Mitsouras Dimitris , Mulkern Robert V. , Rybicki Frank J.
Published: January 2006

Fast spin echo (FSE) trains elicited by nonselective “hard” refocusing radio frequency (RF) pulses have been proposed as a means to enable application of FSE methods for high‐resolution 3D magnetic resonance imaging (MRI). Hard‐pulse FSE (HPFSE) trains offer short echo spacings, but are unfortunately limited to imaging the entire sample within the coil sensitivity thus requiring lengthy imaging times, consequently limiting clinical application. In this work we formulate and analyze two general‐purpose combinations of 3D HPFSE with inner volume (IV) MR imaging to circumvent this limitation. The first method employs a 2D selective RF excitation followed by the HPFSE train and focuses on required properties of the spatial excitation profile with respect to limiting RF pulse duration in the range. The second method employs two orthogonally selective 1D RF excitations (a pair) to generate an echo from magnetization within the volume defined by their intersection. Subsequent echoes are formed via the HPFSE train, placing the focus of the method on (a) avoiding spurious echoes that may arise from transverse magnetization located outside the slab intersection when it is unavoidably affected by the nonselective refocusing pulses and (b) avoiding signal losses due to the necessarily different spacing (in time) of the RF pulse applications. The performance of each method is experimentally measured using Carr‐Purcell‐Meiboom‐Gill (CPMG) multi‐echo imaging, enabling examination of the magnetization evolution throughout the echo train. The methods as implemented achieve 95% to 97% outer volume signal suppression, and higher suppression appears to be well within reach, by further refinement of the selective RF excitations. Example images of the human brain and spine are presented with each technique. We conclude that the SNR efficiency of volume imaging in conjunction with the short echo spacing afforded by hard pulse trains enables high‐resolution 3D HPFSE MRI of a small field‐of‐view (FOV) with minimal aliasing artifact.
Monte Carlo simulations of dose from microCT imaging procedures in a realistic mouse phantom
Authors: Taschereau Richard , Chow Patrick L. , Chatziioannou Arion F.
Published: January 2006

The purpose of this work was to calculate radiation dose and its organ distribution in a realistic mouse phantom from micro‐computed tomography (microCT) imaging protocols. CT dose was calculated using GATE and a voxelized, realistic phantom. The x‐ray photon energy spectra used in simulations were precalculated with GATE and validated against previously published data. The number of photons required per simulated experiments was determined by direct exposure measurements. Simulated experiments were performed for three types of beams and two types of mouse beds. Dose‐volume histograms and dose percentiles were calculated for each organ. For a typical microCT screening examination with a reconstruction voxel size of , the average whole body dose varied from (at ) to (at ), showing a strong dependence on beam hardness. The average dose to the bone marrow is close to the soft tissue average. However, due to dose nonuniformity and higher radiation sensitivity, 5% of the marrow would receive an effective dose about four times higher than the average. If CT is performed longitudinally, a significant radiation dose can be given. The total absorbed radiation dose is a function of milliamperes‐second, beam hardness, and desired image quality (resolution, noise and contrast). To reduce dose, it would be advisable to use the hardest beam possible while maintaining an acceptable contrast in the image.
Iterative regularization in intensity‐modulated radiation therapy optimization
Authors: Carlsson Fredrik , Forsgren Anders
Published: January 2006

A common way to solve intensity‐modulated radiation therapy (IMRT) optimization problems is to use a beamlet‐based approach. The approach is usually employed in a three‐step manner: first a beamlet‐weight optimization problem is solved, then the fluence profiles are converted into step‐and‐shoot segments, and finally postoptimization of the segment weights is performed. A drawback of beamlet‐based approaches is that beamlet‐weight optimization problems are ill‐conditioned and have to be regularized in order to produce smooth fluence profiles that are suitable for conversion. The purpose of this paper is twofold: first, to explain the suitability of solving beamlet‐based IMRT problems by a BFGS quasi‐Newton sequential quadratic programming method with diagonal initial Hessian estimate, and second, to empirically show that beamlet‐weight optimization problems should be solved in relatively few iterations when using this optimization method. The explanation of the suitability is based on viewing the optimization method as an iterative regularization method. In iterative regularization, the optimization problem is solved approximately by iterating long enough to obtain a solution close to the optimal one, but terminating before too much noise occurs. Iterative regularization requires an optimization method that initially proceeds in smooth directions and makes rapid initial progress. Solving ten beamlet‐based IMRT problems with dose‐volume objectives and bounds on the beamlet‐weights, we find that the considered optimization method fulfills the requirements for performing iterative regularization. After segment‐weight optimization, the treatments obtained using 35 beamlet‐weight iterations outperform the treatments obtained using 100 beamlet‐weight iterations, both in terms of objective value and of target uniformity. We conclude that iterating too long may in fact deteriorate the quality of the deliverable plan.
Ki-67 MIB1 labelling index and the prognosis of primary TaT1 urothelial cell carcinoma of the bladder
Authors: Quintero A , Alvarez-Kindelan J , Luque R J , Gonzalez-Campora R , Requena M J , Montironi R , Lopez-Beltran A
Published: January 2006

Aims:To evaluate whether ki-67 labelling index (LI) has independent prognostic value for survival of patients with bladder urothelial tumours graded according to the 2004 World Health Organisation classification.

Methods:Ki-67 LI was evaluated in 164 cases using the grid counting method. Non-invasive (stage Ta) tumours were: papilloma (n = 5), papillary urothelial neoplasia of low malignant potential (PUNLMP; n = 26), and low (LG; n = 34) or high grade (HG; n = 15) papillary urothelial carcinoma. Early invasive (stage T1) tumours were: LG (n = 58) and HG (n = 26) carcinoma. Statistical analysis included Fisher and χ2tests, and mean comparisons by ANOVA andt test. Univariate and multivariate survival analyses were performed according to the Kaplan–Meier method with log rank test and Cox’s proportional hazard method.

Results:Mean ki-67 LI increased from papilloma to PUNLMP, LG, and HG in stage Ta (p<0.0001) and from LG to HG in stage T1 (p = 0.013) tumours. High tumour proliferation (>13%) was related to greater tumour size (p = 0.036), recurrence (p = 0.036), progression (p = 0.035), survival (p = 0.054), and high p53 accumulation (p = 0.015). Ki-67 LI and tumour size were independent predictors of disease free survival (DFS), but only ki-67 LI was related to progression free survival (PFS). Cancer specific overall survival (OS) was related to ki-67 LI, tumour size, and p27kip1 downregulation. Ki-67 LI was the main independent predictor of DFS (p = 0.0005), PFS (p = 0.0162), and cancer specific OS (p = 00195).

Conclusion:Tumour proliferation measured by Ki-67 LI is related to tumour recurrence, stage progression, and is an independent predictor of DFS, PFS, and cancer specific OS in TaT1 bladder urothelial cell carcinoma.
Eosinophilia in the upper gastrointestinal tract is not a characteristic feature in cow’s milk sensitive gastro–oesophageal reflux disease. Measurement by two methodologies
Authors: Nielsen R G , Fenger C , Bindslev-Jensen C , Husby S
Published: January 2006

Background:An association between cow’s milk hypersensitivity (CMH) and gastro–oesophageal reflux disease (GERD) in childhood has been reported in the past decade.

Aim:To assess whether biopsies from the upper gastrointestinal tract of children with cow’s milk sensitive GERD have a specific allergic inflammatory pattern, and to compare two different techniques for measuring inflammatory cells in gastrointestinal biopsies.

Methods:GERD was diagnosed by means of endoscopy and oesophageal pH monitoring. Hypersensitivity to cow’s milk was determined by an elimination diet and cow’s milk challenge. Allergic inflammatory cells in upper gastrointestinal biopsies were identified by immunohistochemistry and their numbers were assessed by two different methods—counting the number of cells/high power field and using the computerised Cast-Grid system.

Results:Cow’s milk sensitive GERD was identified in 10 of 17 children with severe GERD (median age, 7.8 years). Biopsies from children with endoscopic oesophagitis had significantly increased numbers of mast cells and T cells. No differences in the number of eosinophils, mast cells, or T cells were found between children with CMH and those with primary GERD. Several differences were found between the two different histological quantification methods.

Conclusions:CMH was found not only in infants but also in school age children with GERD. Histology did not identify the cow’s milk sensitive GERD subgroup. The computerised histological method provides a more complete evaluation based upon total biopsy area, and helped to limit the bias of uneven biopsy size.
Seasonal variation in mortality from myocardial infarction and haemopericardium. A postmortem study
Authors: Biedrzycki O , Baithun S
Published: January 2006

Background:Seasonal variation in the incidence of and mortality from myocardial infarction (MI) has been well recognised for many years. Haemopericardium (HP) is usually a fatal complication of MI. No data exist in the literature with regard to the seasonal variation in mortality from HP.

Aims:To perform a necropsy based study to confirm seasonal variation in mortality from MI in a London population and to determine whether seasonal variation in mortality from HP can be established.

Methods:Postmortem causes of death issued by several pathologists, working in two public London mortuaries over a five year period from 1999 to 2004 were analysed. Deaths caused by HP secondary to traumatic or iatrogenic causes were specifically excluded, as were deaths caused by HP secondary to bicuspid aortic valve and aortic dissection. The results were subdivided into winter (1 November to 31 March) and summer (1 April to 31 October).

Results:In total, there were 2266 cases of MI and 135 cases of HP. Significantly more deaths from HP (83 of 135; 61.5%; p = 0.004) and MI (1051 of 2266; 46.4%; p = 0.016) occurred in the five month winter period. Furthermore, there was a significantly higher incidence of HP compared with MI during the winter (83/1051; 7.9%) than the summer (52/1215; 4.3%; p<0.001). There was no significant difference in the age or sex of patients dying in either the winter or summer.

Conclusion:There is seasonal variation in mortality from both MI and HP in the London population, as confirmed by a postmortem study.
Expression of osteoprotegerin (OPG), TNF related apoptosis inducing ligand (TRAIL), and receptor activator of nuclear factor κB ligand (RANKL) in human breast tumours
Authors: Van Poznak C , Cross S S , Saggese M , Hudis C , Panageas K S , Norton L , Coleman R E , Holen I
Published: January 2006

Background:Osteoprotegerin (OPG) is involved in the regulation of bone turnover through binding to the receptor activator of nuclear factor κB ligand (RANKL), and has also been reported to be a potential survival factor for several different cell types. The survival effects are mediated through inhibition of the activity of tumour necrosis factor related apoptosis inducing ligand (TRAIL). Both breast and prostate cancer cells produce sufficient amounts of OPG to be protected against the effects of TRAIL in vitro.

Aims:To investigate the spatial expression of OPG, RANKL, and TRAIL in non-neoplastic breast tissue and breast cancer, and its relation with oestrogen receptor (ER) expression.

Methods:Forty breast cancers (20 ER+, 20 ER−) and five non-neoplastic breast tissue samples were stained with antibodies against OPG, RANKL, and TRAIL.

Results:OPG was not expressed in non-neoplastic breast tissue except when colocalised with altered columnar epithelium. RANKL was expressed at the apical surface of luminal epithelial cells and TRAIL was expressed in myoepithelial cells. All three proteins were expressed in some breast cancers but showed no significant association with tumour type. OPG expression showed a significant positive correlation with ER expression (p = 0.011).

Conclusions:This is the first published study of the spatial expression of OPG, RANKL, and TRAIL in breast tissue and breast cancer. The localisation of each protein was specific and they were not colocalised. This specificity may provide a useful marker of functional differentiation in breast cancer; for example, TRAIL expression as a marker of myoepithelial differentiation.
Focal interstitial CC chemokine receptor 7 (CCR7) expression in idiopathic interstitial pneumonia
Authors: Choi E S , Pierce E M , Jakubzick C , Carpenter K J , Kunkel S L , Evanoff H , Martinez F J , Flaherty K R , Moore B B , Toews G B , Colby T V , Kazerooni E A , Gross B H , Travis W D , Hogaboam C M
Published: January 2006

Background/Aims:Idiopathic interstitial pneumonias (IIPs) are a diverse grouping of chronic pulmonary diseases characterised by varying degrees of pulmonary fibrosis. The triggers of the fibroproliferative process in IIP remain enigmatic but recent attention has been directed towards chemokine involvement in this process.

Methods:The expression of two chemokine receptors, CCR7 and CXCR4, and their respective ligands, CCL19, CCL21, and CXCL12, were examined in surgical lung biopsies (SLBs) from patients with IIP. Transcript and protein expression of these receptors and their ligands was compared with that detected in histologically normal margin SLBs.

Results:CCR7 and CXCR4 were detected by gene array and real time polymerase chain reaction analysis and CCR7, but not CXCR4, expression was significantly raised in usual interstitial pneumonia (UIP) relative to biopsies from patients diagnosed with non-specific interstitial pneumonia (NSIP) or respiratory bronchiolitis/interstitial lung disease (RBILD). CCR7 protein was expressed in interstitial areas of all upper and lower lobe UIP SLBs analysed. CCR7 expression was present in 50% of NSIP SLBs, and CCR7 was restricted to blood vessels and mononuclear cells in 75% of RBILD SLBs. Immune cell specific CXCR4 expression was seen in IIP and normal margin biopsies. CCR7 positive areas in UIP biopsies were concomitantly positive for CD45 (the leucocyte common antigen) but CCR7 positive areas in all IIP SLBs lacked the haemopoietic stem cell antigen CD34, collagen 1, and α smooth muscle actin.

Conclusion:This molecular and immunohistochemical analysis showed that IIPs are associated with abnormal CCR7 transcript and protein expression.
Reassessment of a simple chemical method using DCIP for screening for haemoglobin E
Authors: Chapple L , Harris A , Phelan L , Bain B J
Published: January 2006

Background:Haemoglobin E is a variant haemoglobin that can lead to considerable morbidity in compound heterozygous states with β thalassaemia. Therefore, its detection is important because it permits antenatal counselling. The parts of the world where haemoglobin E is prevalent are resource poor and detection can therefore be problematical. A simple visual test using 2,6-dichlorophenolindophenol (DCIP) has been developed in Thailand, but its use has not become widespread. This test has now become available in kit form.

Aims/Methods:To evaluate the new DCIP test kit for the detection of haemoglobin E.

Results:Seventeen of 18 samples from individuals with haemoglobin E gave positive results and one gave an equivocal result. False positive or equivocal results were seen in three of 21 individuals with other disorders of globin chain synthesis but were not seen in normal subjects.

Conclusions:This study evaluated the sensitivity, specificity, and reproducibility of the kit and confirmed the usefulness of the DCIP test as a screening test for haemoglobin E. In countries with limited health resources, its use would reduce the number of samples requiring referral to a central laboratory for definitive tests.
Postmortem bacteriology: a re-evaluation: Table 1
Authors: Morris J A , Harrison L M , Partridge S M
Published: January 2006

Aim:To assess the value of postmortem bacteriology in necropsy practice, with specific emphasis on bacterial invasion of blood and cerebrospinal fluid (CSF).

Methods:A review of published articles on postmortem bacteriology. Studies were selected to cover the full range of necropsy practice including adults, the perinatal period, and infancy. The review covers over 5000 necropsies, mainly in adults, but including 1108 perinatal cases and 468 cases of sudden unexpected death in infancy. Data are available on 4992 blood cultures, 1168 specimens of CSF, and 743 cultures of spleen.

Results:Studies in which careful precautions have been taken to reduce contamination show that approximately two thirds of blood cultures are negative, two in nine yield a single isolate, and one in nine have a mixed growth. The postmortem interval has only a small effect on the isolation rate. A pure growth of a known pathogen has a more than 50% likelihood of being found in association with genuine infection in adults and in the perinatal period.

Conclusions:The main postmortem artefact is contamination, but this can be considerably reduced by careful technique. Agonal spread is less common than is often assumed. Postmortem translocation is not a problem if the body is appropriately stored. A pure growth of a pathogen in blood or CSF should be regarded as a possible contributing factor to death at all ages.
Myopericytoma: a unifying term for a spectrum of tumours that show overlapping features with myofibroma. A review of 14 cases
Authors: Dray M S , McCarthy S W , Palmer A A , Bonar S F , Stalley P D , Marjoniemi V , Millar E , Scolyer R A
Published: January 2006

Background:Myopericytoma (MPC) is a recently proposed term to describe a group of tumours that originate from perivascular myoid cells and show a range of histological growth patterns. Only a small number of series describing MPC have been reported. MPC is frequently misdiagnosed as a sarcoma.

Aims:To document the clinical and histopathological findings of a series of MPCs, to describe the range of growth patterns and morphological spectrum, and to compare MPC with myofibroma (MF).

Patients/Methods:Fourteen patients with features of MPC and/or MF were identified from the archival files of the department of anatomical pathology, Royal Prince Alfred Hospital, Sydney, Australia.

Results:There were six female and eight male patients. The mean and median patient ages were 37 and 35.5 years, respectively. The tumours were located in the skin, subcutis, or superficial soft tissues of the distal extremities (13 patients) or the head and neck region (one patient), and showed a spectrum of morphological appearances. They were divided into two groups based upon the predominant growth pattern corresponding to MPC (seven cases) and MF (seven cases). The feature most suggestive of MPC was the presence of a concentric perivascular arrangement of plump spindle shaped cells. The presence of a zonation/biphasic appearance was most characteristic of MF.

Conclusions:MPC exhibits a spectrum of growth patterns that overlap with MF. Tumours can be designated as MPC or MF depending on the predominant growth pattern.
Pseudoactinomycotic radiate granules of the gynaecological tract: review of a diagnostic pitfall
Authors: Pritt B , Mount S L , Cooper K , Blaszyk H
Published: January 2006

The filamentous bacterium actinomyces can cause serious gynaecological tract infections, including pelvic inflammatory disease (PID) and tubo-ovarian abscess. Thus, definitive diagnosis of actinomycotic granules (AMGs) in gynaecological specimens is clinically important. Non-infectious pseudoactinomycotic radiate granules (PAMRAGs) can mimic the microscopic appearance of AMGs. PAMRAGs may be more common than actinomycotic infections in specimens from patients using intrauterine devices and may be seen in patients with PID. Although the composition and aetiology of PAMRAGs is unclear and variable, a panel of histochemical stains can aid in diagnosis. On haematoxylin and eosin (H&E) stained sections, AMGs show as distinct granules with basophilic peripheral radiating filaments and a dense central eosinophilic core, whereas H&E stained sections of PAMRAGs feature refractile granules with irregular club-like peripheral projections and no central dense core. The filaments of AMGs are Gram positive on Brown and Brenn (B&B) stain and are highlighted with Gomori methenamine silver stain (GMS). They stain negatively with a modified acid fast bacillus (AFB) stain, aiding in the distinction of actinomyces from nocardia. PAMRAGs show negative or non-specific staining with B&B, GMS, and AFB stains. Therefore, knowledge of these staining properties and the distinguishing characteristics of PAMRAGs and AMGs enables recognition of this important diagnostic pitfall.
ON THE GROWTH OF GROUPS AND AUTOMORPHISMS
Authors: BRIDSON MARTIN R.
Published: January 2006

We consider the growth functions βΓ(n) of amalgamated free products Γ = A *C B, where A ≅ B are finitely generated, C is free abelian and |A/C| = |A/B| = 2. For every d ∈ ℕ there exist examples with βΓ(n) ≃ nd+1βA(n). There also exist examples with βΓ(n) ≃ en. Similar behavior is exhibited among Dehn functions.
SUBGROUPS OF FINITELY PRESENTED GROUPS WITH SOLVABLE CONJUGACY PROBLEM
Authors: OLSHANSKII ALEXANDER YU. , SAPIR MARK V.
Published: January 2006

We prove that every countable group with solvable power problem embeds into a finitely presented 2-generated group with solvable power and conjugacy problems.
NONVANISHING OF ALGEBRAIC ENTROPY FOR GEOMETRICALLY FINITE GROUPS OF ISOMETRIES OF HADAMARD MANIFOLDS
Authors: ALPERIN ROGER C. , NOSKOV GENNADY A.
Published: January 2006

We prove that any nonelementary geometrically finite group of isometries of a pinched Hadamard manifold has nonzero algebraic entropy in the sense of M. Gromov. In other words it has uniform exponential growth.
THE FREQUENCY SPACE OF A FREE GROUP
Authors: KAPOVICH ILYA
Published: January 2006

We analyze the structure of the frequency spaceQ(F) of a nonabelian free group F = F(a1,…,ak) consisting of all shift-invariant Borel probability measures on ∂F and construct a natural action of Out(F) on Q(F). In particular we prove that for any outer automorphism ϕ of F the conjugacy distortion spectrum of ϕ, consisting of all numbers ‖ϕ(w)‖/‖w‖, where w is a nontrivial conjugacy class, is the intersection of ℚ and a closed subinterval of ℝ with rational endpoints.
TYPES OF GROWTH AND IDENTITIES OF SEMIGROUPS
Authors: SHNEERSON L. M.
Published: January 2006

In this paper we discuss the problem: how large can the intermediate growth of nilpotent and relatively free semigroups be. We construct a sequence {Sn} of finitely-generated semigroups such that the growth of the semigroup Sn+1 (n = 1,2,…) is intermediate and larger than or equal to the growth of exp (m/φn(m)), where φn(m) is the nth iteration of ln m. All semigroups Sn are nilpotent in the sense of Malcev. We also find the sequence of relatively free semigroups with the same types of growth.
MAXIMAL SUBGROUPS OF SOME NON LOCALLY FINITE p-GROUPS
Authors: PERVOVA E. L.
Published: January 2006

Kaplansky's conjecture claims that the Jacobson radical [Formula: see text] of a group algebra K[G], where K is a field of characteristic p > 0, coincides with its augmentation ideal [Formula: see text] if and only if G is a locally finite p-group. By a theorem of Passman, if G is finitely generated and [Formula: see text] then any maximal subgroup of G is normal of index p. In the present paper, we consider one infinite series of finitely generated infinite p-groups (hence not locally finite p-groups), so called GGS-groups. We prove that their maximal subgroups are nonetheless normal of index p. Thus these groups remain among potential counterexamples to Kaplansky's conjecture.
COMPLEXITY AND ASYMPTOTICAL BEHAVIOR OF A SIRS EPIDEMIC MODEL WITH PROPORTIONAL IMPULSIVE VACCINATION
Authors: ZENG GUANG-ZHAO , CHEN LAN-SUN
Published: January 2006

This paper considers an SIRS epidemic model with proportional impulsive vaccination, which may inherently oscillate. We study the ratio-dependent impulsive control and obtain the conditions about the basic reproductive number for which the epidemic-elimination solution is globally asymptotic. On the other hand, if the epidemic turns out to be endemic, we study numerically the influences of impulsive vaccination on the periodic oscillation of a system without impulsion and find sophisticated phenomena such as chaos in this case.
Effects of portal free fatty acid elevation on insulin clearance and hepatic glucose flux
Authors: Yoshii Hidenori , Lam Tony K. T. , Gupta Neehar , Goh Tracy , Haber C. Andrew , Uchino Hiroshi , Kim Tony T. Y. , Chong Victor Z. , Shah Keyur , Fantus I. George , Mari Andrea , Kawamori Ryuzo , Giacca Adria
Published: January 2006

We tested the hypothesis that, due to greater hepatic free fatty acid (FFA) load, portal delivery of FFAs, as in visceral obesity, induces hyperinsulinemia and increases endogenous glucose production to a greater extent than peripheral FFA delivery. For 5 h, 10 μeq·kg−1·min−1portal oleate ( n = 6), equidose peripheral oleate ( n = 5), or saline ( n = 6) were given intravenously to conscious dogs infused with a combination of portal and peripheral insulin to enable calculation of hepatic insulin clearance during a pancreatic euglycemic clamp. Peripheral FFAs were similar with both oleate treatments and were threefold greater than in controls. Portal FFAs were 1.5- to 2-fold greater with portal than with peripheral oleate. Peripheral insulin concentrations were greatest with portal oleate, intermediate with peripheral oleate ( P < 0.001 vs. portal oleate or controls), and lowest in controls, consistent with corresponding reductions in plasma insulin clearance and hepatic insulin clearance. Although endogenous glucose production did not differ between the two routes of oleate delivery, total glucose output (endogenous glucose production plus glucose cycling) was greater with portal than with peripheral oleate ( P < 0.001) despite the higher insulin levels. In conclusion, during euglycemic clamps in dogs, the main effect of short-term elevation in portal FFA is to generate peripheral hyperinsulinemia. This may, in the long term, contribute to the metabolic and cardiovascular risk of visceral obesity.
Effects of hyperglycemia on glucose metabolism before and after oral glucose ingestion in normal men
Authors: Rigalleau Vincent , Beauvieux Marie-Christine , Gallis Jean-Louis , Gin Henri , Schneiter Phillippe , Tappy Luc
Published: January 2006

The plasma glucose excursion may influence the metabolic responses after oral glucose ingestion. Although previous studies adressed the effects of hyperglycemia in conditions of hyperinsulinemia, it has not been evaluated whether the route of glucose administration (oral vs. intravenous) plays a role. Our aim was to determine the effects of moderately controlled hyperglycemia on glucose metabolism before and after oral glucose ingestion. Eight normal men underwent two oral glucose clamps at 6 and 10 mmol/l plasma glucose. Glucose turnover and cycling rates were measured by infusion of [2H7]glucose. The oral glucose load was labeled by d-[6,6-2H2]glucose to monitor exogenous glucose appearance, and respiratory exchanges were measured by indirect calorimetry. Sixty percent of the oral glucose load appeared in the systemic circulation during both the 6 and 10 mmol/l plasma glucose tests, although less endogenous glucose appeared during the 10 mmol/l tests before glucose ingestion ( P < 0.05). This inhibitory effect of hyperglycemia was not detectable after oral glucose ingestion, although glucose utilization was increased (+28%, P < 0.05) due to increased nonoxidative glucose disposal [10 vs. 6 mmol/l: +20%, not significant (NS) before oral glucose ingestion; +40%, P < 0.05 after oral glucose ingestion]. Glucose cycling rates were increased by hyperglycemia (+13% before oral glucose ingestion, P < 0.001; +31% after oral glucose ingestion, P < 0.05) and oral glucose ingestion during both the 6 (+10%, P < 0.05) and 10 mmol/l (+26%, P < 0.005) tests. A moderate hyperglycemia inhibits endogenous glucose production and contributes to glucose tolerance by enhancing nonoxidative glucose disposal. Hyperglycemia and oral glucose ingestion both stimulate glucose cycling.
Dose-responsive insulin regulation of glucose transport in human skeletal muscle
Authors: Pencek R. Richard , Bertoldo Alessandra , Price Julie , Kelley Carol , Cobelli Claudio , Kelley David E.
Published: January 2006

Glucose transport is regarded as the principal rate control step governing insulin-stimulated glucose utilization by skeletal muscle. To assess this step in human skeletal muscle, quantitative PET imaging of skeletal muscle was performed using 3- O-methyl-[11C]glucose (3-[11C]OMG) in healthy volunteers during a two-step insulin infusion [ n = 8; 30 and 120 mU·min−1·m−2, low (LO) and high (HI)] and during basal conditions ( n = 8). Positron emission tomography images were coregistered with MRI to assess 3-[11C]OMG activity in regions of interest placed on oxidative (soleus) compared with glycolytic (tibialis anterior) muscle. Insulin dose-responsive increases of 3-[11C]OMG activity in muscle were observed ( P < 0.01). Tissue activity was greater in soleus than in tibialis anterior ( P < 0.05). Spectral analysis identified that two mathematical components interacted to shape tissue activity curves. These two components were interpreted physiologically as likely representing the kinetics of 3-[11C]OMG delivery from plasma to tissue and the kinetics of bidirectional glucose transport. During low compared with basal, there was a sixfold increase in k3, the rate constant attributed to inward glucose transport, and another threefold increase during HI (0.012 ± 0.003, 0.070 ± 0.014, 0.272 ± 0.059 min−1, P < 0.001). Values for k3were similar in soleus and tibialis anterior, suggesting similar kinetics for transport, but compartmental modeling indicated a higher value in soleus for k1, denoting higher rates of 3-[11C]OMG delivery to soleus than to tibialis anterior. In summary, in healthy volunteers there is robust dose-responsive insulin stimulation of glucose transport in skeletal muscle.
Temporal Patterns of Field Potentials in Vibrissa/Barrel Cortex Reveal Stimulus Orientation and Shape
Authors: Benison Alexander M. , Ard Tyler D. , Crosby Allison M. , Barth Daniel S.
Published: January 2006

During environmental exploration, rats rhythmically whisk their vibrissae along the rostrocaudal axis. Each forward extension of the vibrissa array establishes rapid spatiotemporal contact with an object under investigation. This contact presumably produces equally rapid spatiotemporal patterns of population responses in the vibrissa representation of somatosensory cortex [the posterior medial barrel subfield (PMBSF)] reflecting features of a stimulus. We used extracellular mapping to identify object features based on spatiotemporal patterns of evoked potentials. Spatiotemporal modeling of evoked potential patterns accurately reconstructed linear versus curved stimuli and detected orientation changes as small as 5°. Whiskers forming arcs in the PMBSF, essential for this reconstruction, may represent a fundamental processing module. We propose that the PMBSF may function as a spatial frequency analyzer, with intrarow processing integrating a complementary set of spatial frequencies from the arcs in a single whisk.
From sequences to a functional unit
Authors: Sivakumar Ashwin , Wilton Christopher , Holm Liisa
Published: January 2006

Functional insights at the gene product level would help the drug discovery industry to effectively tap targets for therapeutics and biomedical applications. A complete functional unit can be multidomain, and it is the co-occurrence and interaction of these multiple domains that determine the function and functional diversity of their gene products. With at least 10% of genes from complete genomes existing in fused form, identifying gene fusion events helps us categorize the protein universe into distinct functional units with only sequence information.
Genetic dissection of proteinuria in the Sabra rat
Authors: Yagil Chana , Sapojnikov Marina , Wechsler Alexander , Korol Abraham , Yagil Yoram
Published: January 2006

The pathophysiology underlying proteinuria remains incompletely understood and warrants further research. We currently initiated the investigation of the genetic basis of proteinuria in the Sabra rat, a model of salt susceptibility that we showed previously to be also a model of spontaneous proteinuria that is unrelated to salt loading or development of hypertension. We applied the total genome scan strategy in 75 F2male animals derived from a cross between SBH/y, which are prone to develop proteinuria, and SBN/y, which are relatively resistant to the development of proteinuria. Animals were subjected to uninephrectomy (UNx) to accelerate the development of proteinuria and were provided chow with a low salt content, thus avoiding the development of hypertension. Urinary protein excretion was monitored before UNx and monthly thereafter for 8 mo. The genotype of F2was determined with microsatellite markers. The data were analyzed for cosegregation by ANOVA and for genetic linkage with a novel multifaceted statistical genetic paradigm. We detected three proteinuria-related quantitative trait loci (QTL) that were associated with the salt sensitivity (H) alleles from SBH/y: SUP2, SUP17, and SUP20 on rat chromosomes (Chr) 2, 17, and 20. We detected an additional QTL on Chr 3, SUP3, that was associated with the salt resistance (N) alleles from SBN/y. A temporal effect was noted: QTL SUP2 and SUP17 surfaced at months 7–8, QTL SUP20 at months 6–8, and QTL SUP3 at months 5–6. The QTL emerging from this study lead us a step closer to identifying the genes associated with and elucidating the pathophysiology of proteinuria.
Chromosome 2p Shows Significant Linkage to Antihypertensive Response in the British Genetics of Hypertension Study
Authors: Padmanabhan Sandosh , Wallace Chris , Munroe Patricia B. , Dobson Richard , Brown Morris , Samani Nilesh , Clayton David , Farrall Martin , Webster John , Lathrop Mark , Caulfield Mark , Dominiczak Anna F. , Connell John M.
Published: January 2006

There is a lack of consistently linked loci influencing blood pressure and hypertension status, and this may be because of genetic or phenotypic heterogeneity. We hypothesize that stratification of subjects by response to antihypertensive drug groups could be used to stringently define subsets that will have reduced genetic and etiologic heterogeneity, by partitioning contrasting mechanisms of hypertension and, thus, enhancing gene finding. We investigated the British Genetics of Hypertension Study population, which is composed of 2142 severely hypertensive white affected sibling pairs. Nonresponse to antihypertensive therapy was defined as an on-treatment blood pressure of >140/90 mm Hg or a difference between prediagnosis and on-treatment blood pressure of <20 mm Hg. Of the nonresponders, there were 89 sibling pairs (AB) who were both on antihypertensive therapy that inhibit the renin–angiotensin system (angiotensin-converting enzyme inhibitors, angiotensin II type-1 receptor blockers, or β-blockers), and 76 sibling pairs (CD) who were both on drugs that do not (calcium channel blockers or diuretics). Nonparametric linkage analysis carried out using markers from a 10-cM genome scan and additional “grid tightening” markers showed significant linkage in the AB group on chromosome 2p (logarithm of odds=4.84 at 90.68 Kosambi cM) and suggestive linkage for the CD group on chromosome 10q (logarithm of odds=2.83 at 125.96 Kosambi cM). The AB linkage locus attained genomewide significance after simulation using 10 000 replicates (
P
=0.005). This locus may contain a gene for the salt-sensitive form of hypertension and/or a pharmacogenetic locus affecting drug response. We have demonstrated for the first time identification of a significant locus by partitioning different pathways of hypertension using drug response.
Enhanced Endothelin Synthesis by Endothelial Cells Exposed to Sera From Pregnant Rats With Decreased Uterine Perfusion
Authors: Roberts Lyndsay , D. LaMarca B. Babbette , Fournier Lillian , Bain Jennifer , Cockrell Kathy , Granger Joey P.
Published: January 2006

The initiating event in preeclampsia is thought be to reduced uteroplacental perfusion. Although we have reported previously that chronic reductions in uterine perfusion pressure (RUPP) in pregnant rats results in hypertension and enhanced endothelin production, the factors linking placental ischemia and endothelial cell activation remain unclear. The purpose of this study was to determine the role of angiotensin II type-1 (AT
1
) receptor activation on endothelin production induced by serum from pregnant rats exposed to reductions in uterine perfusion. To achieve this goal, human umbilical vein endothelial cells were exposed to sera collected from RUPP rats or normal pregnant rats. Arterial pressure was significantly higher in RUPP rats (135±2 mm Hg) than in pregnant rats (106±1 mm Hg). Six hours after exposure to RUPP serum (n=17), cell media endothelin concentration was 18.4±2.7 pg/mL as compared with 9.22±1.3 pg/mL from cells exposed to serum from normal pregnant rats (n=9). Eighteen hours after exposure to RUPP serum (n=7), endothelin concentration was 30.5±3.8 pg/mL as compared with 12.8±5.3 pg/mL from cells exposed to normal pregnant rat serum (n=6). In contrast, serum from RUPP rats did not increase endothelin production in human umbilical vein endothelial cells pretreated with an AT
1
receptor antagonist, losartan (15 μmol/L). Eighteen hours after exposure to RUPP serum and losartan (n=14), endothelin concentration was 21.3±2.2 pg/mL as compared with 16.4±3.3 pg/mL from cells exposed to normal pregnant rat serum and losartan (n=10). These data indicate that serum from pregnant rats exposed to reductions in uterine perfusion enhances endothelin production by endothelial cells via by AT
1
receptor activation.