ABSTRACT
Until now, no reports exist on the existence of femoral bone loss after hip arthroplasty using long-stem cementless prostheses in elderly patients. In a prospective evaluation the amount of bone loss (stress-shielding) after implantation of a long stem hip prosthesis in patients with femoral neck fractures (group A) or pertrochanteric femoral fractures (group B) was examined. Eleven patients (five from group A and six from group B) were treated with a long-stem modular hip prosthesis (MHP). Change of bone mass was evaluated using quantitative computed tomographie (QCT) immediately following and at six months (group A and B) and twelve months (group A) after implantation of the prosthesis. Clinical results, expressed with the modified Harris Hip Score, and relative changes of bone mass were compared with mean periprosthetic bone mass of the femur after operation. After implantation of the MHP, the maximum decrease of mean femoral bone mass was 19.1% at six months and 20.2% at twelve months for group A and 29.5% at six months for group B. Bone loss in the proximal periprosthetic area was higher than in the distal part. There was no correlation between baseline values of bone mass and the amount of stress-shielding or clinical outcome.
Subject(s)
Bone Density/physiology , Bone Diseases, Metabolic/diagnostic imaging , Femoral Neck Fractures/surgery , Femur/diagnostic imaging , Hip Fractures/surgery , Hip Prosthesis , Postoperative Complications/diagnostic imaging , Aged , Aged, 80 and over , Bone Cements , Equipment Failure Analysis , Female , Femoral Neck Fractures/diagnostic imaging , Follow-Up Studies , Hip Fractures/diagnostic imaging , Humans , Male , Middle Aged , Prosthesis Design , Risk Factors , Tomography, X-Ray ComputedABSTRACT
The risk involved in partial liver resections depends mainly on tumor localization, invasion of central vascular structures, and parenchymal function. The imaging techniques available today (computed tomography, magnetic resonance imaging) allow us to detect precisely the extent of tumor invasion and their relationship to central vessels. The various three-dimensional reconstruction techniques are helpful with regard to a virtual planning of liver resections. The calculation of remaining liver volumes subsequent to partial hepatectomies are considered to be an essential predictive parameter in terms for the development of postoperative liver failure. In a retrospective and a later consecutive, prospective clinical study we analyzed the postoperative risk in a series of 570 patients. In an univariate analysis 13 of 31 parameters showed significant values. In multivariate analysis only three parameters (partial hepatic resection rate, PHRR), gamma-glutamyltranspeptidase, and prothrombin activity) were independent parameters for predicting liver failure, generating the most significant values for the PHRR. In our experience the most comfortable and precise technique for evaluating PHRR is the b-spline technique.
Subject(s)
Image Processing, Computer-Assisted , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/surgery , Tomography, X-Ray Computed , Female , Hepatectomy/adverse effects , Humans , Liver Failure/etiology , Liver Neoplasms/enzymology , Liver Neoplasms/pathology , Logistic Models , Male , Patient Care Planning , Postoperative Complications , Predictive Value of Tests , Prospective Studies , Prothrombin Time , Retrospective Studies , Risk Assessment , Risk Factors , gamma-Glutamyltransferase/metabolismABSTRACT
With multislice spiral computed tomography (MSCT), existing indications for performing CT of the chest are strengthened and new applications are emerging. The high speed of MSCT improves efficiency, image quality and patient comfort of "routine" imaging of the chest. The ability to cover large volumes with thin slices improves the evaluation of mediastinal lymph nodes and pulmonary nodules and allows for high-quality secondary reconstruction. If a comprehensive diagnosis of the mediastinal structures and the pulmonary parenchyma is desired, MSCT for the first time allows reconstruction of contiguous and high-resolution (HRCT) sections from the same set of thin-collimation raw data. This way, contiguous chest images of superior and HRCT sections of equal image quality compared to conventional CT scanning can be obtained. Vascular protocols greatly benefit from the high speed of MSCT: For imaging the thoracic aorta or pulmonary emboli (PE), the amount of contrast material can be substantially reduced. Owing to thin collimation, the detection rate of small peripheral emboli can be significantly increased. If indicated, the entire subphrenic venous system can be evaluated during the same session, without additional contrast material.
Subject(s)
Radiography, Thoracic/methods , Tomography, X-Ray Computed/methods , Adult , Aorta, Thoracic/diagnostic imaging , Contrast Media/administration & dosage , Diagnostic Tests, Routine/methods , Electrocardiography , Female , Humans , Lung Diseases/diagnostic imaging , Male , Middle Aged , Thoracic Arteries/diagnostic imagingABSTRACT
Band 4.1 provides, besides ankyrin, the main linkage between the erythrocyte membrane and its cytoskeleton. Its predominant binding sites in the membrane are located on the glycophorins. However, the cytoplasmic domain of band 3 can also bind band 4.1. We have studied which of the different band 3 oligomers observed (monomers, dimers, tetramers) can act as band 4.1 binding sites, by equilibrium sedimentation experiments on mixtures of purified band 3 and dye-labelled band 4.1 in solutions of a nonionic detergent. At low molar ratios of band 4.1 and band 3, the sedimentation equilibrium distributions obtained could all be perfectly fitted assuming that only two dye-labelled particles were present: uncomplexed band 4.1 and a complex formed between one band 4.1 molecule and one band 3 tetramer. The presence of small amounts of complexes containing band 3 monomers or dimers could not be completely ruled out but is unlikely. On the other hand, stabilized band 3 dimers effectively bound band 4.1. At higher molar band 4.1/band 3 ratio, the band 3 tetramer apparently could bind up to at least four band 4.1 molecules. The band 4.1/band 3 tetramer complex was found to be unstable. The results described, together with those reported previously, point at a prominent role of tetrameric band 3 in ligand binding.
Subject(s)
Anion Exchange Protein 1, Erythrocyte/metabolism , Cytoskeletal Proteins , Cytoskeleton/metabolism , Erythrocyte Membrane/metabolism , Membrane Proteins/metabolism , Neuropeptides , Binding Sites , Detergents , Humans , SolutionsABSTRACT
Vitreoretinal proliferation (PVR) is an important cause of severe visual loss in eyes with penetrating injuries. The aim of this work was to study the occurrence of early signs of PVR in eyes with penetrating injuries and no indication for vitrectomy within the first 14 days and to identify the factor that correlates most with high incidence and early onset of PVR. Furthermore, the aggressiveness of PVR in this group of patients was studied. We examined 51 patients (mean age 36 years) with penetrating ocular injuries using indirect ophthalmoscopy and B- and A/B-scan-echography. The mean follow-up interval was 24 months. The factor that correlated most with high incidence and early onset of PVR was a scleral laceration length of > 6 mm. The incidence of PVR was at any time significantly higher in eyes with a scleral laceration length of > 6 mm than in eyes with a scleral laceration length of < 6 mm (P < 0.0313). A negative correlation was shown between the length of the scleral laceration and the time of onset of PVR (r = 0.3441; P = 0.0006). Four eyes (8%) underwent vitrectomy because of aggressive development of PVR. A scleral laceration length of > 6 mm is the most important risk factor for high incidence and early onset of PVR in eyes with penetrating injuries with no indication for vitrectomy within the first 14 days.
