Difference between type I autoimmune inhibitors of fibrin stabilization in two patients with severe hemorrhagic disorder.

Inhibitors of fibrin stabilization of apparently autoimmune origin, found in two severely bleeding unrelated patients (W. G. and G. A.), were compared with regard to their biological target specificities, potencies and immunological characteristics. Both interfered only with the activation of fibrin stabilizing factor (coagulation Factor XIII) and, while totally preventing the conversion of this zymogen to the functional transamidating enzyme, fibrinoligase (Factor XIII(a)), they showed very little inhibition toward the enzyme itself. Thus, according to the classification of Lorand concerning biological specificities, both can be characterized as Type I inhibitors of fibrin stabilization. Potencies of the two inhibitors were quite similar when measured in conjunction with the plasma zymogen, but they differed remarkably in tests with platelet Factor 13. The inhibitor of patient W. G. prevented the activation of the zymogen from platelets, but that of G. A. had no effect on the platelet factor. It may therefore be concluded that the inhibitor of W. G. is directed exclusively against the a subunit which is a common constituent of plasma as well as platelet factors. The inhibitor of G. A., however, must be targeted against determinants uniquely characteristic for the ab ensemble of the plasma zymogen including the b subunit. On the basis of this difference in target specificity, the inhibitor of W. G. is designated as Type I-1 and that of G. A. as Type I-2. The inhibitors of both patients were isolated as immunoglobulins, and neutralization tests revealed that the antibody of W. G. comprised mainly heavy chains of the IgG1 and light chains of the kappa class. The antibody of G. A. proved to be considerably more heterogeneous and contained IgG1 and IgG3 heavy chains as well as kappa- and lambda-light chains. The finding that the antibody of W. G. inhibited conversion of platelet Factor 13 and also its thrombinmodified form, but had no effect on the thrombin and Ca(2+)-activated factor, is an indication that antigenic determinants existing both on the native zymogen and on its hydrolytically modified form become buried in the Ca(2+)-dependent step of activation. This is clear evidence for the occurrence of a significant conformational change in the protein structure attendant to the process of unmasking of its enzymic activity.

The effect of clinical history on chest radiograph interpretations in a PACS environment.

The effect that accompanying patient information has on diagnostic accuracy in radiologic interpretation has been studied by many researchers but remains a matter of contention. Experiments in the past emphasized the chest film because this procedure is the one done most frequently in radiology. However, with the increasing importance of digital imaging, the role of patient history in these procedures should be assessed. The use of a model computerized patient history in the interpretation of digitized chest images that were displayed on a high-resolution workstation was studied. Two hundred forty-seven selected posteroanterior chest images that indicated disease and that indicated no disease were interpreted in random sequence by five board-certified radiologists, with and without accompanying patient histories. Readers were prompted by the response forms to evaluate images for the possible occurrence of interstitial diseases, nodules, or pneumothorax. No significant differences (P = .05) in the detection of these abnormalities were noted between case readings with and without history for any of the radiologists or for the group as a whole. However, this methodology reflects a direct interpretation approach. The results of this study may not necessarily be applicable to individual prompts, different imaging procedures, or other abnormalities.

Effect of two rating formats in multi-disease ROC study of chest images.

ROC methodology has been expanded in recent years to include multi-disease experiments. To accommodate these changes, different rating formats, general or disease specific, can be used. No experimental data are available concerning the possible effects of the rating format on the results of these studies. We performed a multi-observer, multi-disease study in which 196 chest images were rated using a format where each disease was evaluated individually and one in which the cases were evaluated without scoring a specific disease. The results indicate that for our data set, the overall assessment of accuracy was not significantly affected by the study format used. Thus, in spite of the difficulties in selecting appropriate controls and the necessity of reassessing sample size considerations, the disease-specific format appears to produce an assessment of accuracy equivalent to that produced by the general format. This equivalence permits the use of the disease-specific approach since it more closely simulates the readers' true environment and is more appropriate for comparing imaging systems that may have a relative accuracy that is disease specific.

Effect of observer instruction on ROC study of chest images.

Receiver-operating characteristic (ROC) analysis has been used in many medical imaging applications during the past decade. In order to ensure that reader-confidence ratings are analyzable (well distributed to meet convergence requirements of curve-fitting algorithms) and meaningful (limit extrapolation of the data), many investigators train readers specifically for this purpose. No experimental data are available concerning the possible effects of such training on the results of ROC studies. We performed a multi-observer, multi-disease study in which 300 chest images were rated by four radiologists before and after they were trained to provide well-distributed confidence ratings. The results indicate that for our data set, reader and disease-specific accuracy was not significantly affected by the training process for interstitial disease and pneumothoraces. However, the accuracy of two readers was significantly affected for the detection of nodules (P less than 0.05), and the overall accuracy of one reader was significantly affected for the classification of normal versus abnormal images (P less than 0.01). Thus, in spite of the difficulties associated with the performance of ROC studies in a free-reading environment, one should carefully consider the possible effects of any intervention on the results prior to conducting ROC studies.

Acetabular anatomy and the transacetabular fixation of screws in total hip arthroplasty.

An anatomical and radiographic study was undertaken to determine the safest zones in the acetabulum for the transacetabular placement of screws during uncemented acetabular arthroplasty. To avoid injury to intrapelvic structures, which are not visible to the surgeon during placement of the screws, cadavera were studied to define the location of these structures with respect to fixed points of reference within the acetabulum. Four clinically useful acetabular quadrants were delineated. The quadrants are formed by drawing a line from the anterior superior iliac spine through the center of the acetabulum to the posterior fovea, forming acetabular halves. A second line is then drawn perpendicular to the first at the mid-point of the acetabulum, forming four quadrants. The posterior superior and posterior inferior acetabular quadrants contain the best available bone stock and are relatively safe for the transacetabular placement of screws. The anterior superior and anterior inferior quandrants should be avoided whenever possible, because screws placed improperly in these quadrants may endanger the external iliac artery and vein, as well as the obturator nerve, artery, and vein. The acetabular-quadrant system provides the surgeon with a simple intraoperative guide to the safe transacetabular placement of screws during primary and revision acetabular arthroplasty.

Fractures and vertebral bone mineral density in patients with renal osteodystrophy.

We investigated the relationship of CT determined vertebral bone mineral density (BMD), type of renal osteodystrophy, N terminal PTH levels and fracture history in 31 dialysis patients. BMD for patients with bone biopsy documented osteitis fibrosa was 1.6 standard deviation (SD) above the normal value for age and sex matched controls, while those patients with low turnover osteodystrophy had a mean BMD 1.2 SD below normal (p less than 0.0001). Three patients with osteitis fibrosa who had previously been treated with prednisone had a low BMD (1.8 SD below normal, different than O, p = 0.0015). There was no correlation between BMD and time on dialysis (r = 0.1). An N terminal PTH level greater than 150 pg/ml was a sensitive (94%) and specific (100%) method of separating those patients with osteitis fibrosa from those with low turnover osteodystrophy, while BMD was much less useful in this differentiation. A low BMD was not predictive of fracture history but the type of renal osteodystrophy was. Patients with low turnover osteodystrophy had a fracture rate of 0.2 fractures/dialysis year in comparison to those with osteitis fibrosis who had 0.1 fractures/dialysis year. Patients with the former bone disease fractured mainly axial rather than appendicular bones in contrast to those patients with osteitis fibrosa. In conclusion we found that patients with osteitis fibrosa had increased BMD compared to normal while those with low turnover osteodystrophy had decreased BMD, but that the N terminal PTH level was a better predictor of the type of bone disease present than was BMD.

Plantar medial subluxation of the medial cuneiform: case report of an uncommon variant of the Lisfranc injury.

An uncommon injury of plantar medial subluxation of the medial cuneiform as a variant of the Lisfranc fracture subluxation is presented. The mechanism of injury is discussed and a comparison is made to previous case reports of variants of medial cuneiform injury.

Three-dimensional angio-computed tomography. New technique for imaging the acetabulum and adjacent vessels in a patient with acetabular protrusio.

An arterial injury is an infrequent but potentially lethel occurrence after primary or revision total hip arthroplasty complicated by an acetabular protrusio. Frequently, a plain radiograph and an arteriogram are used to assess the major arteries around the hip. The limitations of these techniques are well documented. A novel technique for documenting the spatial relationships of the external iliac and common femoral arteries to the acetabulum employs an arterial study combined with a three-dimensional computed scan. An angiocatheter is inserted by conventional radiographic technique and a standard computed scan with 3-mm sections is obtained and reconstructed to a three-dimensional image. The scan provides an accurate three-dimensional image of the osseous architecture and arterial images around the acetabulum. Even in the presence of a metallic arthroplastic component, the resolution of the three-dimensional angio-computed scan is sufficient to identify the external iliac artery adjacent to the pelvis.

A subluxing arthropathy associated with the anti-Jo-1 antibody in polymyositis/dermatomyositis.

Of 180 patients with polymyositis/dermatomyositis (PM/DM) seen at the University of Pittsburgh and affiliated hospitals since 1975, 21 of 100 tested positive for the anti-Jo-1 antibody. Sixteen of the 21 patients were women and 18 were white. Fifteen had adult PM, 4 had myositis in overlap with scleroderma, and 2 had adult DM. Evidence of interstitial lung disease was found in 12 of 18 anti-Jo-1 positive patients (67%), but in only 15 of 79 anti-Jo-1 negative patients (19%) (P less than 0.0002). The 21 anti-Jo-1 positive patients were divided into 3 separate groups based on the observed articular findings. Four patients had a deforming, predominantly nonerosive arthropathy with subluxations of the distal interphalangeal joints, especially the thumbs. Eight patients had a nondeforming arthropathy primarily affecting the small joints of the hands, wrists, shoulders, and knees. Those with deformities had a longer duration of arthritis compared with those with nondeforming arthropathy (mean 14.5 years versus 3.3 years). Nine anti-Jo-1 positive patients had no joint arthropathy. Three of 4 patients with deformities have required articular reconstructive surgery for subluxation, with 2 having associated subcutaneous calcinosis.

Clinical and radiographic improvement of bone of the second lumbar vertebra in Paget's disease following therapy with etidronate disodium: a case report.

Paget's disease of bone is most commonly seen in the spine; it may either be asymptomatic or may cause pain and neurologic impairment. We describe a patient with back pain due to Paget's disease of the second lumbar vertebra and spinal stenosis. The patient had a dramatic clinical and radiographic response to 2 courses of etidronate disodium, which was evidenced by resolution of the back pain and improvement in bony spinal stenosis. Etidronate may be effective in reversing bony spinal stenosis due to Paget's disease.

Groin and hip pain due to fractures at or near the pubic symphysis.

Three patients with fractures at or near the pubic symphysis presented with groin pain simulating hip fracture or arthritis. A 71-year-old osteoarthritic woman was treated with a nonsteroidal antiinflammatory drug (NSAID) and exercises for right-sided sciatic pain after a minor fall, but developed left groin pain and tenderness over the pubic symphysis after two days of exercise. She had an impacted fracture of the left pubic symphysis which responded to use of a cane. The second patient was a 90-year-old woman with rheumatoid arthritis (on steroids) who complained of right hip pain after a series of falls in her home. Initially treated with Buck traction for a presumed hip fracture, she was later treated with heat and exercises after negative hip x-rays were obtained. Retrospective analysis of pelvic films and bone scan revealed a right pubic symphysis fracture. The third patient was an 83-year-old rheumatoid arthritic woman with inability to walk secondary to left groin pain. Pubic tomograms revealed disruption of the superior aspect, and bone scan showed increased uptake of the left pubic bone. She was treated with moist heat, rest, and NSAID. Twenty-four cases of os pubis fractures without major trauma or symphysis disruption have been reported. All patients had osteoporosis, and six had rheumatoid arthritis. Our three cases are presented to increase awareness of pubic symphysis fractures as a cause for groin pain, especially in patients with osteoporosis and rheumatoid arthritis.

Acetabular fractures: three-dimensional computer tomographic imaging and interactive surgical planning.

Three-dimensional imaging can provide a valuable perceptual link between conventional radiographs and axial computed tomographic scans in the evaluation of complex acetabular fractures. With the 3D83 computer program, three-dimensional images can be generated to correlate with standard radiographic views. Unique images can also be created that offer perspectives unobtainable by conventional radiography. More sophisticated interactive techniques allow computer simulation of surgical approaches.

Three-dimensional computed tomography of acetabular fractures.

Computer programs that produce 3D surface reformations from sets of contiguous axial CT scans were used in evaluating a variety of acetabular fractures in 20 patients. The 3D images were easily correlated with plain radiographs, and new views were produced that provided a unique perspective not obtainable by conventional radiography. The 3D images were useful in complex displaced fractures in cases in which the interpretation of plain radiographs was difficult. Plain radiographs and conventional CT scans were more sensitive than the 3D images in detecting undisplaced fractures.

Adult-onset Still's disease. Clinical course and outcome.

We reviewed the long-term natural history of 21 adult-onset Still's disease patients. Patient subsets were identified according to clinical course patterns. These included monocyclic systemic disease in 4, polycyclic systemic disease in 2, chronic articular monocyclic systemic disease in 10, and chronic articular polycyclic systemic disease in the remaining 5 patients. Functional outcome differed according to course patterns and the extent of articular involvement. Systemic manifestations, per se, did not contribute to poor functional prognosis. Chronic articular disease had the worst outcome: 27% evolved to functional class III status, compared with none in the cyclic systemic groups. Those patients who had a chronic articular pattern or a polyarticular onset and course were at higher risk to develop disabling arthritis. An aggressive approach to therapy, including the early use of remittive agents, should be considered in these patient subsets.

Storage phosphor radiographs vs conventional films: interpreters' perceptions of diagnostic quality.

We compared storage phosphor images with high-quality conventional film-screen images by evaluating physicians' perceptions of image quality and their levels of confidence in making diagnostic interpretations. Eight physicians each examined 11 posteroanterior storage phosphor chest images (obtained with an experimental high-resolution storage phosphor system) side by side with conventional film images of the same patients. The storage phosphor images were obtained only minutes after the conventional radiographs were obtained. Storage phosphor images were digitally printed onto films in two different formats: a full-size (12 X 14 in. [30.5 X 35.6 cm]) and a half-size format of four computer-processed, minified images (6 X 7 in. [15.2 X 17.8 cm] each). Most of the responses rated the quality and resolution/sharpness of conventional images, as well as their ability to display the complete lung field, as either "excellent" or "good"; however, the storage phosphor images received significantly better ratings (p less than .05). Computer-processed minified versions of the storage phosphor images also received better ratings than did the conventional images. When the physicians were asked to rate their confidence level in making diagnoses with each of the two techniques, in 74 of 88 cases they indicated that their level of confidence would be at least as high when using the storage phosphor images as when using the conventional images.

Synchronous multicentric osteosarcoma: the case for metastases.

OBJECTIVE: There is a current debate whether multicentric osteosarcoma represents synchronous multiple primary osteosarcomas or metastatic disease. The purpose of this report is to evaluate the etiology, presentation, and classification of this entity. DESIGN AND PATIENTS: Six patients ranging in age from 7 to 29 years were studied. The clinical, radiographic, and pathologic findings are reported. In addition, a review of the literature was undertaken. RESULTS: The clinical courses of our six patients as well as a review of the literature suggest that multicentric osteosarcoma represent one extreme of a continuous scale of metastatic osteosarcoma rather than multiple synchronous primary tumors. The presentation is unusual and the clinical behavior distinctive, but the mechanism of spread remains the same: blood-borne and lymphatic-borne. CONCLUSIONS: Our experience with these six patients supports the concept in the recent literature that synchronous osteosarcoma is one extreme of the spectrum of metastatic osteosarcoma. Its unique features are: (1) multiple radiodense lesions that present simultaneously with or without pulmonary metastases; (2) a single "dominant" lesion with multiple smaller lesions; and (3) a uniformly rapid, fatal prognosis. Osteosarcoma should be regarded as a metastatic disease, even when only a single primary lesion is found at the initial presentation.

Effect of low-dose calcitriol and calcium therapy on bone histomorphometry and urinary calcium excretion in osteopenic women.

We evaluated low-dose calcitriol (0.25 microgram b.i.d.) in combination with 1 g of supplemental calcium therapy as treatment for osteopenic women over 60 years of age (n = 4). Control patients (n = 6) received ergocalciferol (50,000 units twice a week) and 1 g of supplemental calcium. Bone biopsies and CT-determined bone mineral density were done initially and after 1 year of therapy. Bone mineral density increased from 77 +/- 18 to 88 +/- 9 mg/ml (NS) in the calcitriol-treated group and from 87 +/- 13 to 112 +/- 30 mg/ml (NS) in the ergocalciferol-treated group. There was also no significant change in bone volume, as determined by bone biopsy in either group. No compression fractures occurred in either treatment group. After 1 year of therapy, urinary calcium excretion was increased significantly above that observed in age-matched untreated women. Creatinine clearance did not change significantly. Hypercalcemia was rare. In summary, we found calcitriol was not superior to ergocalciferol in preventing progressive bone loss and fractures. Both therapies were associated with significant hypercalciuria.

Pelvic and acetabular fractures: examination by angled CT scanning.

A new technique of direct angled CT scanning of pelvic and acetabular fractures is presented that allows visualization of the entire ring on a single image or two adjacent images.

Serum sex hormones and severity of osteoarthritis of the hand.

OBJECTIVE: To examine the relationship of endogenous sex hormones to the severity of radiographic hand osteoarthritis (ROA) in 229 white women, mean age 74 years. METHODS: Hand ROA was graded according to the Kellgren-Lawrence scale and according to individual features of OA: osteophytes, joint space narrowing, subchondral sclerosis, lateral deformity and joint collapse. Two measures of hand ROA were considered: the worst joint score assigned to any one of 10 hand joints and the sum of the scores for the 10 joints. RESULTS: Comparison of the age and obesity adjusted sex hormone concentrations by the worst Kellgren-Lawrence score or the worst score of the individual features of OA revealed little difference. There were no trends in the sex hormone concentrations with increasing severity of hand ROA. CONCLUSIONS: Our results do not support an association between endogenous hormone levels and severity of hand ROA.