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Biomedical subjects

A L Jacob

Publications and source records attributed to A L Jacob.

At least 19 recordsLinked to original sources
PubMed2005

[Interdisciplinary emergency room management of trauma patients from the standpoint of coworkers].

INTRODUCTION: The purpose of this study was to examine whether staff questionnaire evaluation is useful for quality control in the emergency room (ER) setting. METHODS: Consecutive anonymous questionnaires (Likert scale 1-5) were filled out by the involved medical staff in all ER trauma cases in a university hospital from July 2002 to December 2003 (analysis of variance, P<0.05). RESULTS: In 171 ER cases, 844 staff members responded. Main criticisms concerned time management or satisfaction with personal ER training (Likert <4). Consultants rated the quality of their training significantly higher than younger doctors, two thirds of consultants vs one third of residents having passed an Advanced Trauma and Life Support course (P<0.001). Depending on responders' professional specialties and whether the situation concerned multiple trauma (Injury Severity Score >15), a significant systematic difference resulted. CONCLUSION: Our standardized staff questionnaire evaluation was revealed to be a discriminative instrument for quality management of trauma cases in the ER. To confirm these findings, correlation with clinical outcome data and further validation of the method are needed.

Attitude of Health Personnel↗
PubMed2005

Multiple-trauma management: standardized evaluation of the subjective experience of involved team members.

BACKGROUND AND OBJECTIVE: Staff attitude plays a pivotal role in quality management. The objective of the present study was to further define how interdisciplinary emergency hospital staff experience their daily work and the extent to which the professional speciality and training of an individual influences his/her assessment of multiple-trauma team performance. METHODS: The clinical staff involved in multiple-trauma emergency management of a university hospital was asked to answer a confidential questionnaire. Factorial analysis was used to identify 8 major dimensions from a total of 53 items. RESULTS: The questionnaire was returned by 128 team members. All professional groups were most dissatisfied with the dimensions 'education and training', 'work sequence between specialities' and 'communication between specialities'. Assessment of the quality of in-hospital emergency-trauma management differed significantly between professional specialities (ANOVA, F=5.2; P=0.028); surgeons gave the highest ratings for all but one dimension. Having taken an Advanced Trauma Life Support (ATLS) course influenced significantly the total rating of multiple-trauma treatments of anaesthetists and surgeons (F=5.5; P=0.024). CONCLUSIONS: The perceptions of interdisciplinary trauma team members without the completion of an ATLS training course were that they did not communicate enough with each other and that there were differences between their expectations and reality. The differences and the communication deficits were overcome in team members who had passed an ATLS course.

Anesthesia↗
PubMed2003

Adapting the fluoroscope to image-guided surgery.

Image-guided techniques have been well established in all surgical disciplines for years. To achieve an optimised work flow during image-guided surgery, the surgeon should be able to manipulate the visual feedback and therefore the imaging unit. C-arm fluoroscopy is the imaging modality routinely used for intraoperative imaging in orthopaedic surgery. The C-arm fluoroscope is positioned and handled by a radiographer on vocal commands, which means that the surgeon depends on external help to manipulate the visual feedback and the work flow is not optimised. The MEPUC interface adapts the C-arm fluoroscope to the needs of image-guided orthopaedic procedures. MEPUC is an acronym for Motorised Exact-Positioning Unit for C-arm. In the hardware component of the MEPUC a conventional C-arm fluoroscope is equipped with stepping motors. The software component allows the surgeon to control the motorised movements of the fluoroscope. The MEPUC interface enables the surgeon to position the C-arm fluoroscope independently in the operating room. Further advantages are achievable when the MEPUC interface is combined with surgical navigation, as this combination allows fully automatic reproduction of former projections. Clinical experience with the MEPUC interface suggests that the work flow for intraoperative imaging is improved and personal requirements reduced.

Fluoroscopy↗
PubMed2001

Acetylation of steroidogenic factor 1 protein regulates its transcriptional activity and recruits the coactivator GCN5.

Steroidogenic factor-1 (SF-1) is an orphan nuclear receptor that plays an essential role in the development of the hypothalamic-pituitary-gonadal axis in both sexes. SF-1 belongs to the hormone nuclear receptor superfamily and possesses an N-terminal DNA binding domain and a C-terminal ligand binding domain. Activation function domain 2 is located C-terminal of the ligand binding domain of SF-1 and is important for the transactivation of target genes. Coactivators with histone acetyltransferase activity such as cAMP response element-binding protein-binding protein and steroid receptor coactivator 1 interact and increase SF-1-mediated transcriptional activity. In this study we demonstrate that SF-1 is acetylated in vivo. Histone acetyltransferase GCN5 acetylates SF-1 in vitro. Moreover, we found that SF-1 recruited a novel coactivator GCN5, which can be a newly identified coactivator for SF-1. Acetylation of SF-1 stimulates its transcriptional activity. Inhibition of deacetylation by trichostatin A, a histone deacetylase inhibitor, increased SF-1-mediated transactivation and stabilized and induced the nuclear export of the SF-1 protein.

Acetylation↗
PubMed2001

Volumetric model determination of the tibia based on 2D radiographs using a 2D/3D database.

We present a new concept with mathematical background for the construction of a three-dimensional (3D) volumetric model of the human tibia based on two conventional orthogonal two-dimensional (2D) radiographic images. This approach is supported by a computer database containing a collection of 80 2D/3D image data sets of individual cadaveric tibiae. For each of these tibiae, the database contains digitized 2D orthogonal radiographic images in both anterior and lateral views, and the corresponding 3D CT data obtained by computerized tomography. To obtain a 3D model of a tibia for a given patient, shape matching is performed. The computer finds the most similar tibia to the patient's tibia among the 2D radiographic images in the database by applying a matching process. To improve accuracy, a 2D image warping procedure can be applied on the slices of the selected bone prior to 3D reconstruction. The warping process is controlled by the contour data of the two orthogonal views. We found that the 3D model thus achieved was useful for virtual preoperative planning and for simulation of the internal fixation of long bones.

Cadaver↗
PubMed2001

[Technology integration and process management. Concept and implementation of a new platform for simultaneous diagnosis and therapy of acutely ill and injured patients and for elective computer assisted surgery (CAS)].

Modern imaging and computer technology gain more and more importance in surgery. This is true for elective and emergency diagnosis and treatment. However integration of technology and optimization of process management is severely behind. A new diagnostic-therapeutic platform should balance this deficit. The platform is composed of a fully equipped operation room environment with integrated high end computer-tomography with navigation, a digital subtraction angiography and an OR- and imaging-table particularly developed for this set-up. The platform may be used for elective diagnosis, for diagnosis and therapy in polytraumatized patients in one and the same location (one stop shop) and for computer assisted surgery (CAS). Bringing the technology to the patient and not the patient to the technology can save time consuming and potentially dangerous transports and expensive personnel can be reduced. Navigation-technology and high quality intra-operative imaging expand the spectrum of minimally invasive surgery.

Diagnostic Imaging↗
PubMed2001

[Radiation exposure of the patient by intraoperative imaging of intramedullary osteosyntheses].

MATERIAL AND METHOD: 39 patients with pertrochanteric femur fracture (n = 32) or lower leg fracture (n = 7) were treated with closed intramedullary nailing. The related radiation exposure of the patients was calculated. RESULTS: Osteosynthesis of pertrochanteric fractures took less fluoroscopic time than osteosynthesis of lower leg fractures. The effective dose was 14 mSv for nailing osteosynthesis of proximal pertrochanteric fractures and less than 0.1 mSv for osteosynthesis of distal lower leg fractures. CONCLUSION: Radiation exposure of the patient due to intraoperative fluoroscopic imaging during osteosynthesis can be estimated based on the data given above. Intraoperative observations imply, consequent application of radiation protection by the orthopaedic surgeons may reduce intraoperative radiation exposure even more.

Female↗
PubMed2001

[Navigation systems for image-guided therapy: A review].

Navigation systems for image-guided therapy: A review. Navigation is visually interactive targeting based on the simultaneous display of instrument position and of the corresponding two- or three-dimensional image data sets. In this way it unifies anatomic information and therapeutic action. Medical navigation systems (MNS) can simulate realtime image guidance and thereby reduce radiation exposure as well as provide the full range of digital image processing during an intervention. Navigation is based on the tracking of medical instruments in space and the transformation of image, patient, and instrument coordinates into a common reference system. If the patient coordinate system is used as the common base, the process is called patient-based navigation (PBN). If, however, the imaging modality is present in the interventional suite and its reference system is used, modality-based navigation (MBN) results. MBN does not need pre-interventional registration and inherently provides intra-operative imaging. In neurosurgery MNS's have been well established since years. They are in use for frameless biopsies and for minimizing the access morbidity in deeply situated pathologies. Currently there is a fast expansion of navigation into other surgical disciplines, e.g., orthopaedic surgery. The clinical accuracy of an MNS is hard to determine since an independent method of measurement is mostly not available during surgery. Normally, a deviation of below one up to about 5 mm between the display of the MNS and the actual position of an anatomic structure is reported. So far there have been only very few prospective randomized clinical trials between conventional and navigated interventions.

Forecasting↗
PubMed2000

Surgical navigation based on fluoroscopy--clinical application for computer-assisted distal locking of intramedullary implants.

OBJECTIVE: Fluoroscopy is used to guide surgical instruments during orthopedic procedures. Radiation exposure and lack of spatial information are drawbacks of this method. Improvements are expected when fluoroscopy-based surgical navigation is used for intraoperative guidance, e.g., in computer-assisted distal locking of intramedullary implants. PATIENTS AND METHODS: The method was applied to 42 interlocking procedures during implantation of the short proximal femoral nail in 27 patients with pertrochanteric femoral fractures. Precision of interlocking, exposure time, operating time, and number of personnel required for computer-assisted distal locking were recorded. RESULTS: One misplaced interlocking screw was observed (2.3%), and contact between the drill bit and the nail during drilling was noticed in 8 cases (19%). The average exposure time was 16 seconds (range 4-42 seconds), and the procedure took an average of 43 min (range 20-70 min). The number of persons required for computer-assisted distal locking was reduced from three to one within the course of the study. CONCLUSIONS: Fluoroscopy-based surgical navigation provided precise intraoperative guidance for computer-assisted distal locking with minimal use of fluoroscopy. The complex system and related procedure times may be drawbacks in this application. Clinical studies are underway to define implants and surgical procedures where intraoperative guidance by fluoroscopy-based surgical navigation is beneficial for the patient and/or surgeon.

Computer Simulation↗
PubMed2000

The multifunctional therapy room of the future: image guidance, interdisciplinarity, integration and impact on patient pathways.

With few exceptions the interventional rooms of the present are either imaging suites or sterile operating rooms. Their users are restricted to either percutaneous procedures or to two-staged image-guided surgery without intra-operative imaging control. Since interventional therapy of the future will be minimally invasive and since minimally invasive therapy is essentially image-guided therapy, a new physical place for these activities has to be devised: the multifunctional therapy room of the future integrates sophisticated imaging and image guidance modalities together with advanced surgical and life-support equipment in a sterile environment [1, 2, 3]. Even given a high degree of integration, this will be a complex and costly piece of medical technology. These two factors--complexity and cost-- require interdisciplinary technological and medical collaboration to bring it into existence, distribute its cost and maximize usage and medical benefit. Yet another dimension of multifunctionality will be introduced and a significant impact on the care of vitally threatened patients will be exerted by using this room not only for elective image-guided therapy but also for emergent one-stop diagnosis and treatment. Motivation, technology, implementation strategies and funding of this image-guided, integrated and interdisciplinary therapy room, as well as a comprehensive approach combining emergency care and elective computer-assisted therapy (CAT), are discussed in this paper.

Critical Pathways↗
PubMed2000

A whole-body registration-free navigation system for image-guided surgery and interventional radiology.

RATIONALE AND OBJECTIVES: To develop and test an image-guided navigation system in which the base of reference is taken from the imaging modality, here, a helical CT scanner. METHODS: An optical digitizer together with a calibration device is used to measure the transformation matrix between the digitizer reference system and a CT reference system. During intervention, it tracks radiological and surgical tools with tool references. A specific software visually integrates the current tool position with the corresponding image information. In vitro accuracy tests were performed. RESULTS: With helical CT, freehand positioning accuracy was 1.9 +/- 1.1 mm (mean +/- SD) in vitro (n = 718). CONCLUSIONS: The navigation system developed by the authors appears to be feasible for radiological interventions as well as for minimally invasive surgery. It is not limited to a certain procedure, can be used in every region of the body, and is functional after imaging. Intraprocedural scans can be integrated immediately.

Equipment Design↗
PubMed1998

Mutations in the activation function-2 core domain of steroidogenic factor-1 dominantly suppresses PKA-dependent transactivation of the bovine CYP17 gene.

Steroidogenic factor-1 (SF-1) is a nuclear receptor that is essential for the proper development and function of steroid hormone-producing cells. The activation function-2 (AF-2) domain in SF-1 is a short alpha-helix in the C terminus that is conserved with respect to other nuclear receptors and is important for transactivation of target genes. In order to investigate the possible role of the AF-2 domain of SF-1 in cAMP-dependent transcriptional regulation of the bovine steroid hydroxylase gene CYP17, mutations were introduced and the effects were characterized. The mutant SF-1 proteins were expressed at comparable levels in nonsteroidogenic Cos-1 cells that lack SF-1, and their abilities to bind an SF-1 site from the CYP17 gene were not affected. Transient transfections of wild-type and mutant SF-1 in Cos-1 cells showed that the capacity to transactivate a reporter gene under the control of the SF-1 site from CYP17 was reduced by the mutations in the AF-2 domain of SF-1. A point mutation in the AF-2 region, E454A, resulted in a relative reporter gene activity that was 21% of that observed with wild-type SF-1. Co-transfections of adrenocortical Y-1 cells, which express endogenous SF-1, with the catalytic subunit of cAMP-dependent protein kinase (PKA-C) and the SF-1-dependent reporter gene showed on average a 16-fold increase in activity in the presence of PKA-C. Introduction of the AF-2 mutants of SF-1 into Y-1 cells completely abolished the PKA-C-mediated stimulation of the reporter gene. The transdominant negative effect of the mutant SF-1 proteins suggests that the AF-2 domain is essential for the activation of SF-1 by the cAMP-dependent protein kinase-dependent signaling pathway.

Animals↗
PubMed1996

Cloning of T-cell antigen receptor beta chain cDNAs from Atlantic salmon (Salmo salar).

Atlantic salmon (Salmo salar) cDNAs encoding the T-cell antigen receptor beta chain (TCRB) were isolated from leukocyte RNA by reverse transcription - polymerase chain reaction (RT-PCR). Twenty-five distinct cDNA fragments covering the variable (V) - diversity (D) - joining (J) junction and part of the constant (C) region were characterized; the sequences of which indicate interchangeable V/D/J usage and expression in the context of one TCRBC gene. Full-length TCRBC sequence information was derived from a leukocyte cDNA library. Key residues of the salmon TCRBC region are in good agreement with those of other species. One distinct exception is the absence of the hinge region cysteine residue which is involved in covalent bonding between the alpha and beta chain in mammalian TCRs. As in amphibian and avian species, the salmon TCRBC membrane proximal region is considerably shorter than the mammalian. An octamer sequence (GGACAGGG) very similar to amphibian, avian, and mammalian D sequences could be recognized in the VDJ junctions from salmon. The pattern of VDJ variability also indicates that mechanisms like trimming and addition occur in fish as in higher vertebrates. Compared with mammals, a relatively high frequency (32%) of the VDJ junctions in salmon were out of frame.

Amino Acid Sequence↗
PubMed1996

Lower extremity angiography: improved image quality and outflow vessel detection with bilaterally antegrade selective digital subtraction angiography. A blinded prospective intraindividual comparison with aortic flush digital subtraction angiography.

RATIONALE AND OBJECTIVES: To introduce routine bilaterally antegrade selective stationary digital subtraction angiography (DSA), and prospectively compare it with unselective stationary DSA in the detection of calf arteries and assess additional time and complication rate. METHODS: Twenty-five patients received one unselective and two separate antegrade selective studies of each calf. Images were evaluated for image quality, number of depicted run-off vessels, and potential crural bypass recipient arteries. RESULTS: Bilaterally antegrade selective DSA was significantly superior in image quality and motion artifacts (P < 0.01). The number of adequately depicted run-off arteries per calf increased from 79% (2.37 of 3) to 96% (2.89 of 3) for legs with advanced peripheral vascular disease (PVD). Seventy-nine instead of 62 potential bypass recipients were identified (P = 0.002). Mean procedure time needed for selective catheterizations was 7 minutes. No adverse events were seen. CONCLUSIONS: Bilaterally antegrade selective DSA clearly is superior to aortic run-off DSA depicting tibial arteries. It requires comparatively small additional effort. Outflow vessel detection essentially is independent of advanced PVD.

Aged↗