bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shoulder prostheses treating cuff tear arthropathy: A comparative biomechanical study
Authors: De Wilde L. F. , Audenaert E. A. , Berghs B. M. 
Published: May 2004

AbstractPainful cuff tear arthropathy (CTA) affects the independence of the elderly. Surgical treatment often consists of joint replacement, the functional outcome of which remains variable. Knowledge of the biomechanical properties of the different prosthetic designs can guide the orthopaedic surgeon in the choice of implant to predict its clinical result. A 3‐D computer model of the glenohumeral joint is used to analyse the moment of the deltoid muscle in the scapular plane.A geometrical 3‐D ball‐and‐socket model of the shoulder joint was used to calculate (1) the angle–force relationships, (2) the moment arm of the deltoid muscle and (3) the moment of the deltoid muscle components, for increasing degrees of arm elevation in the scapular plane. In this 3‐D model, a clinical thoraco‐scapular rhythm analysis was implemented, based on measurements in normal subjects, patients treated with an anatomical prosthesis and patients treated with an inversed delta III prosthesis®. These data were compared for 10 different prosthetic treatment options.Results. Muscle angle–force curves show a favourable slope in non‐anatomical prosthetic designs, where the centre of rotation of the glenohumeral joint is medialized, the deltoid muscle is elongated and the humeral shaft is lateralized. On the contrary, anatomical prosthetic designs do not perform well in this computer analysis.Conclusions. From a biomechanical point of view, a shoulder prosthesis which medializes the centre of rotation, lengthens the deltoid muscle and increases the deltoid lever arm, results in a significantly more powerful abduction of the shoulder, despite complete loss of rotator cuff function.Relevance. This study explains why a successful functional outcome can be expected in CTA with a reversed prosthesis. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Viable osteoblastic potential of cortical reamings from intramedullary nailing
Authors: Frölke Jan Paul M. , Nulend Jenneke Klein , Semeins Cor M. , Bakker Fred C. , Patka Peter , Haarman Henk J. Th. M. 
Published: May 2004

AbstractTo analyze the effect of intramedullary reaming on fracture healing, we investigated whether or not cortical reamings contain viable bone cells. There are several tissue components contained in medullary reamings including blood, bone marrow and cortical bone. This study is focused on the cortical reamings, which are produced during reaming of the medullary cavity. They may stimulate fracture healing but it is still unclear if they contain vital bone cells. We tested the hypothesis that these cortical reamings are a source of viable bone cells and compared cell cultures with cultivated cells from iliac crest biopsies. Responses of protein content and ALP activity to vitD stimulation in the cells were considered as properties of viability. Ten in tact living sheep femora were fully reamed and the cortical reamings were cultivated in a standard manner and compared with cultivated cells from ipsilateral iliac crest biopsies from the same animals. Cells started to grow from the reamings as well as the iliac crest within 2–5 days, and covered the entire culture flask within 9–13 days. Protein content and ALP activity in cells from both reamings and iliac crest were significantly responsive to vitD stimulation. Cortical reamings from intramedullary nailing have osteoblastic potential and contain living bone cells similar to bone cells from the iliac crest. These findings may further explain the superior healing of fractures, treated with reamed nailing. © 2004 Orthopaedic Research Society. Published y Elsevier Ltd. All rights reserved.
Effects of rotation on measurement of lower limb alignment for knee osteotomy
Authors: Kawakami Hideo , Sugano Nobuhiko , Yonenobu Kazuo , Yoshikawa Hideki , Ochi Takahiro , Hattori Asaki , Suzuki Naoki 
Published: May 2004

AbstractThe purposes of this study were to clarify the effects of rotation on two‐dimensional measurement of lower limb alignment for knee osteotomy using a three‐dimensional method and to determine whether this 3‐D simulation method could help with planning of knee osteotomy. We developed computer software to calculate femorotibial angle (FTA) and hip–knee–ankle angle (HKA) and simulate knee osteotomy from a CT‐based 3‐D bone model of the lower limb. Lower limb rotation on anteroposterior long‐standing radiographs was measured by superimposing the 3‐D bone models. Changes in alignment with limb rotation were calculated using the software. FTA after virtual closed‐wedged osteotomy was measured for a hypothetical case of a rotation error of the osteotomy plane in reattaching the proximal cutting surface to the distal cutting surface. For 31 varus knees in 20 patients with medial compartment arthritis, the mean rotation angle, relative to the epicondylar axis, with variable limb position was 7.4 ± 3.9° of internal rotation (mean ± SD), ranging from 8° of external rotation to 14° of internal rotation; the mean changes in FTA and HKA were 3.5 ± 2.2° (range, 0.4–8.6) and 1.6 ± 1.3° (range, 0.2–4.9), respectively. The FTA “flexion angle” (lateral view alignment from neutral AP) and the absolute HKA “flexion angle” correlated with the change in FTA and HKA with limb rotation, respectively (FTA, R = 0.999; HKA, R = 0.993). The mean change in FTA after virtual closed‐wedged osteotomy was 3.2° for internal and external 10° rotation errors in reattaching the osteotomy plane. Rotation may affect measurement of lower limb alignment for knee osteotomy, and 3‐D methods are preferable for surgical planning. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Diversity and Evolution of Mitochondrial RNA Editing Systems
Authors: Gray Michael 
Published: May 2004

Abstract'RNA editing' describes the programmed alteration of the nucleotide sequence of an RNA species, relative to the sequence of the encoding DNA. The phenomenon encompasses two generic patterns of nucleotide change, 'insertion/deletion' and 'substitution', defined on the basis of whether the sequence of the edited RNA is colinear with the DNA sequence that encodes it. RNA editing is mediated by a variety of pathways that are mechanistically and evolutionarily unrelated. Messenger, ribosomal, transfer and viral RNAs all undergo editing in different systems, but well‐documented cases of this phenomenon have so far been described only in eukaryotes, and most often in mitochondria. Editing of mRNA changes the identity of encoded amino acids and may create translation initiation and termination codons. The existence of RNA editing violates one of the long‐accepted tenets of genetic information flow, namely, that the amino acid sequence of a protein can be directly predicted from the corresponding gene sequence. Particular RNA editing systems display a narrow phylogenetic distribution, which argues that such systems are derived within specific eukaryotic lineages, rather than representing traits that ultimately trace to a common ancestor of eukaryotes, or even further back in evolution. The derived nature of RNA editing raises intriguing questions about how and why RNA editing systems arise, and how they become fixed as additional, essential steps in genetic information transfer. IUBMB Life, 55: 227‐233, 2003
DNA Damage Regulation of the RNA Components of the Translational Apparatus: New Biology and Mechanisms
Authors: Schultz Michael 
Published: May 2004

AbstractIt was shown more than 30 years ago that expression of ribosomal (r) RNAs processed from the large precursor rRNA is repressed when eukaryotic cells are exposed to genotoxic stress. More recently it has been found that other RNA components of the translational machinery, the tRNAs and 5S rRNA transcribed by RNA polymerase (pol) III, are also downregulated in cells that have experienced DNA damage. In other words, the DNA damage response involves coordinate repression of genes whose products comprise the heart of the translational machinery. This repression could be due to blockage of polymerase elongation, and indeed this mechanism was originally invoked to explain repression of pol I‐transcribed rRNAs under conditions of genotoxic stress. Recent work however reveals the existence of a DNA damage signaling pathway that directly contributes to downregulation of the pol III and probably the pol I transcription initiation machinery. This pathway involves a highly conserved protein kinase, CK2. Its likely target is the TATA Binding Protein, which in most eukaryotes is required for transcription by both pol I and pol III. Here I consider the implications of these findings for our understanding of the physiology of the DNA damage response, and for the prospect of developing a comprehensive molecular model of how cells cope with genotoxic stress. IUBMB Life, 55: 243‐247, 2003
Protein Insertion into the Inner Membrane of Mitochondria
Authors: Herrmann Johannes , Neupert Walter 
Published: May 2004

AbstractThe inner membrane of mitochondria harbours a large number of polypeptides, many of which have evolved from proteins of the prokaryotic progenitors of mitochondria. The sorting routes on which these proteins are integrated into the mitochondrial inner membrane reflect their phylogenetic origin: Proteins of eukaryotic descent typically reach their destination following arrest of import at the level of the inner membrane. In contrast, many proteins inherited from the prokaryotic progenitor cell are inserted into the inner membrane in an export step following translocation into the matrix. Recently, three different insertion pathways from the matrix into the inner membrane were identified which show considerable parallels to the protein insertion processes in bacteria and chloroplasts. Two of these pathways depend on the related inner membrane proteins Oxa1 and Cox18. A third route is less well defined and depends on the membrane‐associated matrix protein Mba1. IUBMB Life, 55: 219‐225, 2003
Target Selection and Determination of Function in Structural Genomics
Authors: Watson James , Todd Annabel , Bray James , Laskowski Roman , Edwards Aled , Joachimiak Andrzej , Orengo Christine , Thornton Janet 
Published: May 2004

AbstractThe first crucial step in any structural genomics project is the selection and prioritization of target proteins for structure determination. There may be a number of selection criteria to be satisfied, including that the proteins have novel folds, that they be representatives of large families for which no structure is known, and so on. The better the selection at this stage, the greater is the value of the structures obtained at the end of the experimental process. This value can be further enhanced once the protein structures have been solved if the functions of the given proteins can also be determined. Here we describe the methods used at either end of the experimental process: firstly, sensitive sequence comparison techniques for selecting a high‐quality list of target proteins, and secondly the various computational methods that can be applied to the eventual 3D structures to determine the most likely biochemical function of the proteins in question. IUBMB Life, 55: 249‐255, 2003
Mitochondrial DNA Replication: What We Know
Authors: Clayton David 
Published: May 2004

AbstractSince the isolation and physical characterization of mammalian mitochondrial DNA (mtDNA) over 35 years ago, numerous works have been published that have examined its physical structure and properties, including its mode of replication and transcription. The established replication model posits that leading‐strand replication of mammalian mtDNA begins at closely spaced, defined sites located downstream from a major transcription promoter and proceeds unidirectionally with displacement of the parental leading strand until approximately two‐thirds of the closed circular mtDNA has been copied. As a consequence, the replication fork passes a major origin for lagging‐strand synthesis, exposing it in single‐stranded form. Displacement as a single‐strand is thought to allow the characteristic secondary structure of this origin to occur, thereby permitting initiation of lagging‐strand synthesis. A natural consequence of the separate and distinct locations of the two origins is that the two segregated progeny mtDNA circles are of two types: one a duplex circle with a newly synthesized leading strand and the other a gapped circle with a partial newly synthesized lagging strand. In each case, the final steps of synthesis and ligation result in closed circular mtDNA products. Recently, mammalian mtDNA isolates have been subjected to 2D‐gel electrophoretic analysis in attempts to assign features to mtDNA molecules that, by virtue of their anomalous migration behavior, could infer them to be candidates for replication intermediates. This review will describe the essential features of the historical findings of mammalian mtDNA replication studies and integrate the more recent observations in developing a current model for this process. IUBMB Life, 55: 213‐217, 2003
Parallels in Genome Evolution in Mitochondria and Bacterial Symbionts
Authors: Burger Gertraud , Lang B Franz 
Published: May 2004

AbstractMitochondria, the energy‐producing organelles of the eukaryotic cell, originate from an endosymbiotic α‐proteobacterium. These organelles are believed to have arisen only once in evolutionary history, but despite their common ancestry, mitochondrial DNAs vary extensively throughout eukaryotes in genome architecture and gene content. New insights into early mitochondrial genome evolution come from the investigation of primitive mitochondriate eukaryotes, as well as the comparison between mitochondria and intracellular bacterial symbionts. IUBMB Life, 55: 205‐212, 2003
Early Cell Evolution, Eukaryotes, Anoxia, Sulfide, Oxygen, Fungi First (?), and a Tree of Genomes Revisited
Authors: Martin William , Rotte Carmen , Hoffmeister Meike , Theissen Ursula , Gelius‐Dietrich Gabriel , Ahr Simone , Henze Katrin 
Published: May 2004

AbstractGenomes contain evidence for the history of life and furthermore contain evidence for lateral gene transfer, which was an important part of that history. The geological record also contains evidence for the history of life, and newer findings indicates that the Earth's oceans were largely anoxic and highly sulfidic up until about 0.6 billion years ago. Eukaryotes, which fossil data indicate to have been in existence for at least 1.5 billion years, must have therefore spent much of their evolutionary history in oxygen‐poor and sulfide‐rich environments. Many eukaryotes still inhabit such environments today. Among eukaryotes, organelles also contain evidence for the history of life and have preserved abundant traces of their anaerobic past in the form of energy metabolic pathways. New views of eukaryote phylogeny suggest that fungi may be among the earliest‐branching eukaryotes. From the standpoint of the fungal feeding habit (osmotrophy rather than phagotrophy) and from the standpoint of the diversity in their ATP‐producing pathways, a eukaryotic tree with fungi first would make sense. Because of lateral gene transfer and endosymbiosis, branches in the tree of genomes intermingle and occasionally fuse, but the overall contours of cell history nonetheless seem sketchable and roughly correlateable with geological time. IUBMB Life, 55: 193‐204, 2003
Pedestrian excitation of bridges
Authors: Newl D E 
Published: May 2004

This paper reviews the evidence on dynamic bridge loading caused by moving pedestrians. The phenomenon of ‘synchronization’ by which people respond naturally to an oscillating bridge when this has a frequency close to their natural walking or running frequency is a feature of this phenomenon. By increasing modal damping, synchronization can be prevented, but how much damping is needed in any particular situation? If some simplifying assumptions about how people walk are made, it is possible to predict analytically the minimum damping required to ensure that synchronization does not lead to high vibration levels. The main assumption is that the movement of a pedestrian's centre of mass has two components. One is its natural movement when the person is walking on a stationary pavement. The other is caused by movement of the pavement (or bridge) and is in proportion to pavement amplitude but with a time delay that is arbitrary. When the time delay is a ‘worst case’, pedestrians act as a source of negative damping. This theory supports the adoption of a non-dimensional number which measures the susceptibility of a bridge to pedestrian excitation. Although currently there are not many good bridge response data, predictions using this non-dimensional number are compared with the data that are available and found to be in satisfactory agreement. Both lateral and vertical vibrations are considered.
Cerebral CT and MRI findings in cervicocephalic artery dissection
Authors: Pelkonen O. , Tikkakoski T. , Pyhtinen J. , Sotaniemi K. 
Published: May 2004

Purpose: To explore the frequency and patterns of brain infarction and other brain manifestations in cervicocephalic artery dissection (CCAD) and to evaluate the correlation between vessel wall findings and infarctions. Material and Methods: The medical records and films of 136 consecutive CCAD patients diagnosed in Oulu University Hospital during the 20‐year period since 1982 were reviewed. Five patients with no brain imaging were excluded. Results: One‐hundred‐and‐twenty‐seven patients underwent cerebral CT and four patients MRI. Brain infarction was detected in 73 patients (56%), 43 of whom had cerebral infarction associated with anterior circulation dissection and 30 cerebellar infarction associated with posterior circulation dissection. Occlusion of the dissected vessel was accompanied by infarction in 76%, irregular stenosis in 40%, and other findings in 12%. Of the anterior circulation infarctions, territorial and subcortical infarctions and territorial infarctions with fragmentation, which are considered embolic, accounted for 95%, while only 5% were in the watershed area and considered hemodynamic. Intracranial posterior circulation dissection rarely caused infarction (in 1/11 of the dissected vessels), whereas intracranial anterior circulation dissection resulted in infarction more commonly (9/12). Altogether 23% of patients with intracranial CCAD had subarachnoid hemorrhage. Hemorrhagic transformation was present in five patients. Conclusions: More than half of CCAD patients have cerebral or cerebellar infarction at CT or conventional MR imaging. Occlusion of the dissected vessel is accompanied by infarction more often than other vessel wall abnormalities. Most cerebral infarctions caused by arterial dissections are of embolic origin. Intracranial dissections cause subarachnoid hemorrhage in more than 20% of patients.
Comparison of intracranial 3D‐ToF‐MRA with and without parallel acquisition techniques at 1.5t and 3.0t: preliminary results
Authors: Gaa J. , Weidauer S. , Requardt M. , Kiefer B. , Lanfermann H. , Zanella F. E. 
Published: May 2004

Purpose: To evaluate the performance of four 3D‐ToF magnetic resonance angiography (MRA) sequences with and without integrated parallel acquisition techniques (iPAT) at 1.5T and 3.0T in imaging intracranial vessels. Material and Methods: Seven volunteers and 5 patients (4 aneurysms, 1 AVM) underwent 3D‐ToF‐MRA at 1.5T (Magnetom Sonata) and 3.0T (Magnetom Trio) with and without parallel acquisition techniques (iPAT) using similarly designed 8‐channel phased‐array head coils. Imaging time of the pulse sequences was set to 7.15 and 7.35 min, respectively. Images were analyzed quantitatively by calculating signal‐to‐noise (SNR) and contrast‐to‐noise (CNR) ratios of proximal M2 segments and qualitatively by using a 5‐point scale. Results: SNR and CNR were significantly higher for both 3D‐ToF sequences at 3.0T compared with both pulse sequences at 1.5T. The highest SNR and CNR were obtained at 3.0T without iPAT. However, because of a higher spatial resolution (matrix 512×640) visualization of small vessel details was best at 3.0T with iPAT. Conclusion: Intracranial 3D‐ToF‐MRA at 3.0T offers superior image quality compared with 1.5T, particular in the delineation of smaller vessels. In contrast to 1.5T, implementation of iPAT at 3.0T is of additional benefit since the high SNR available at 3.0T allows for higher spatial resolution without prolongation of measurement time.
Role of skeletal scintigraphy in advanced retinoblastomas
Authors: Barai S. , Bandopadhayaya G. P. , Raj P. , Julka P. K. , Kumar R. , Malhotra A. , Dhanpathi H. , Nainiwal S. , Haloi A. K. 
Published: May 2004

Purpose: To document the incidence of skeletal metastases exclusively in advanced cases of retinoblastoma and to rationalize the use of preoperative skeletal scintigraphy in such patients. Material and Methods: Preoperative bone scans of 36 consecutive patients with advanced retinoblastoma who underwent skeletal scintigraphy during 1998 to 2003 were analyzed retrospectively. Bone scans were classified as: Grade 1 (high probability scan for skeletal metastases), Grade 2 (equivocal malignant or benign abnormalities), or Grade 3 (normal or certainly benign lesions). Results: Grade 1 scan was found in 3 (8.33%) patients; bone metastases were confirmed by additional investigations. Grade 2 scan was found in 5 (13.88%) patients; bone metastases were excluded in all by additional investigations. Grade 3 scan was found in the remaining 28 (77.77%) patients. Extraorbital extension of disease was demonstrated by fine needle aspiration of lymph nodes in five patients, which included all three patients with Grade 1 scan. In addition to lymph node metastases, two patients had intracranial extension of the disease; demonstrated by contrast‐enhanced magnetic resonance imaging of the head. One patient had liver metastases detected on abdominal ultrasound. None of the patients had skeletal metastases only. Conclusion: Routine preoperative bone scan is not justified in patients with locally advanced retinoblastoma. Bone scan should only be performed in patients with documented extraocular metastatic disease.
Systemic‐to‐pulmonary venous shunt in superior vena cava obstruction: depiction on computed tomography venography
Authors: Kim H.‐C. , Chung J. W. , Park S. H. , Kim H. B. , Jae H. J. , Lee W. , Park J. H. 
Published: May 2004

Purpose: To describe computed tomography (CT) venographic appearances of systemic‐to‐pulmonary venous shunts with CT venography and three‐dimensional reconstruction images from patients with superior vena cava obstruction. Material and Methods: From January 1994 to April 2002, CT venography was performed in 45 patients with superior vena cava obstruction using a single‐detector helical CT scanner ( n=38) and four‐detector row CT scanner ( n=7). Analysis of CT scan data included the cause and degree of venous obstruction, the presence of pleural thickening and enhancement, and the attenuation of pulmonary veins. The causative factor for systemic‐to‐pulmonary venous shunt was evaluated using the Fisher exact test. Results: Systemic‐to‐pulmonary venous shunts were observed in four patients (9%) who had high‐attenuated pulmonary veins and pleural enhancement on CT venography. Pleural thickening ( P=0.01) and a history of pulmonary tuberculosis ( P=0.034) are statistically significant risk factors. Conclusion: CT venography showed strong pleural enhancement and high‐attenuated pulmonary veins indicating systemic‐to‐pulmonary venous shunts. Radiologists should study the earlier enhancement of pulmonary veins in patients with superior vena cava obstruction.