Characterization of a plasminogen activator inhibitor induced by glucocorticoids in immature bovine Sertoli cell-enriched cultures.

Plasminogen activation has been shown to be inhibited by the cell-specific production of a number of protease inhibitors belonging to the serine protease inhibitor family. In the bovine testis this inhibitor production is induced by glucocorticoids. Monospecific antibodies raised against the three known classes of plasminogen activator inhibitor were used to identify which type of inhibitor was secreted by bovine Sertoli cell-enriched cultures. Immunoblot analysis and [35S]methionine labelling of newly synthesized proteins revealed that a novel protein with an apparent molecular weight of 49 kDa, which shares antigenic determinants with placental and macrophage PAI and fibroblast protease nexin, is secreted in response to dexamethasone stimulation. This protein was shown by immunoadsorption to be a functionally active inhibitor of both tissue-type and urokinase-type plasminogen activators.

Only tissue-type plasminogen activator is secreted by immature bovine Sertoli cell-enriched cultures.

Two molecular variants of plasminogen activator (PA): urokinase (uPA) and tissue-type plasminogen activator (tPA), have been reported to be synthesized in the rat testis. Data obtained in this study using monospecific antibodies raised against uPA and tPA in immunoblotting and bioimmunoassay protocols consistently demonstrate that only tPA (and not uPA) is synthesized by bovine Sertoli cell-enriched cultures, and is induced by bovine FSH. Zymographic analysis of conditioned medium on gels containing plasminogen and casein showed a dominant PA proteolytic band (72 kDa) which co-migrated with human tPA. A proteolytic band (43 kDa), which was also secreted by FSH-stimulated cells, was not present when protection was afforded from auto-proteolysis by aprotinin, and was therefore concluded to be a proteolytic fragment of tPA, and not uPA.

Modulation of plasminogen activation by glucocorticoid hormones in the rat granulosa cell.

Granulosa cells from immature rats primed with diethylstilbestrol (DES) showed a fivefold rise in the activity of secreted plasminogen activator (PA) in response to human FSH. The dose giving 50% of the maximum response (ED50) was 10 ng/ml. Glucocorticoid hormones significantly suppressed PA activity in both control cells and cells stimulated with FSH (ED50 = 50 nmol dexamethasone/l; 1 mumol corticosterone/l). Cortexolone (2.5 mumol/l) significantly ameliorated this suppression, indicating that the response to glucocorticoids is receptor-mediated. These data, together with the time delay required for glucocorticoids to take effect (5 h), suggest that glucocorticoids induce the production of a specific PA inhibitor in granulosa cells.

Small bilateral renal cell carcinomas.

A case of multicentric bilateral small renal cell carcinomas is presented. The two largest tumors were detected by computerized tomography (CT) and the diagnosis confirmed by ultrasound and fine needle biopsy.

Magnetic resonance imaging differentiation of compression spine fractures or vertebral lesions caused by osteoporosis or tumor.

STUDY DESIGN: This study reviewed the magnetic resonance imaging characteristics of atraumatic compression fractures or vertebral lesions caused by osteoporosis of tumor. OBJECTIVES: The purpose of this study was to evaluate the magnetic resonance imaging characteristics that will allow differentiation of compression fractures or vertebral lesions due to osteoporosis or tumor. SUMMARY OF BACKGROUND DATA: Previous reports have identified several magnetic resonance imaging characteristics of benign and malignant compression fractures. However, diagnosis has been confirmed primarily by clinical follow-up and not pathologic biopsy specimen. METHODS: Thirty-four cases of atraumatic compression fractures or vertebral lesions that had undergone magnetic resonance imaging evaluation followed by biopsy were retrospectively reviewed. Conventional magnetic resonance imaging with T1- and T2-weighted images were obtained in all cases and gadolinium was used in 21 cases. Each case was evaluated for magnetic resonance imaging characteristics of the compression fractures or vertebral lesions that included decreased T1 and increased T2 signal, marrow preservation on the T1 image, gadolinium lesion enhancement, multiple level involvement, associated soft tissue mass, posterior vertebral expansion, and pedicle involvement. RESULTS: Eighteen of the compression fractures or vertebral lesions were confirmed as tumor and 16 were confirmed as osteoporosis by biopsy. Decreased T1- weighted and increased T2-weighted signals are sensitive but not specific for tumor involvement. Normal marrow preservation of the compressed vertebral body on T1 imaging is consistent with an osteoporotic fracture or lesion. Gadolinium enhancement, multiple level involvement, and posterior vertebral expansion are not useful for differentiation of osteoporotic from tumor fractures or lesions. Pedicle involvement or an associated soft tissue mass are specific for a tumor compression fracture or vertebral lesion. CONCLUSIONS: There are characteristic magnetic resonance imaging findings of compression fractures or vertebral lesions that allow sensitive and specific differentiation of osteoporosis from tumor.

Mathematical precision in rotational corrective osteotomy of the femur.

We used a mathematical model to determine whether the approach to derotation of the malrotated femur can be improved for use in corrective osteotomy of the femur. Rotational corrective osteotomy of the femur (RCOF) is a procedure performed by orthopedic surgeons to correct congenital femoral torsion deformities and posttraumatic femoral shaft malunions. In the conventional technique, osteotomy is performed at the malrotation site, and correction is achieved by rotating the distal segment of the femur so that the patella and toes point upward, symmetric with the normal leg when the patient is in the supine position. This approach does not ensure the rotational position of the proximal segment of the femur, and malrotation can still persist. Intraoperative muscle spasm or preoperative soft tissue contracture may alter the proximal segment rotation immediately after osteotomy. Although marked improvement in the accuracy of measuring the malrotation angle for RCOF has been made possible by the computed tomography and magnetic resonance imaging, the orthopedic surgeon does not have a defined approach for transforming this value from degrees to millimeters so that derotation of the femur can be achieved intraoperatively with precision. We carried out studies using ten cadaver femurs with malrotation angles of 15 to 44 degrees to see if this surgical technique can be improved by a mathematical model that converts the malrotation angle value (in degrees) to an equivalent value on the circle circumference (in millimeters). Our results show errors of 0.5 to 4.5 degrees in the rotation angle and virtually eliminate the error of malrotation associated with RCOF. We suggest that our model is clinically applicable and that its definitive value will arise from clinical applications.

Percutaneous computed-tomography-stabilization of pelvic fractures: preliminary report.

The authors performed percutaneous computed-tomography (CT)-guided stabilization of reproduced pelvic fractures in eight cadaver studies and in three additional clinical cases. The details of the technique are illustrated in this article. The authors conclude that percutaneous CT-guided stabilization of pelvic fractures in selected cases can be performed safely, rapidly, and with less associated morbidity than conventional open methods presently used. Clinical studies are currently being expanded.

Magnetic resonance imaging of hepatic adenoma.

A case of hepatic adenoma imaged by magnetic resonance imaging (MRI) as well as with angiography, computed tomography, and radionuclide imaging is presented. Pathological correlation is also presented. Review of the literature of MRI of hepatic adenoma and related tumors is discussed.

A 45-year-old woman with right shoulder pain.

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Percutaneous computed tomography stabilization of moderate to severe slipped capital femoral epiphysis.

A percutaneous computed tomography (CT) guided pinning of experimentally reproduced slipped capital femoral epiphysis in five cadavers and one patient--who had bilateral pinning for moderate and severe grade chronic slip--was conducted. Prior investigations of cadavers revealed that this procedure can be performed in selected cases. The details of the technique are illustrated in this article.

Sacral chordoma with unusual posterior radiographic presentation.

Chordoma is a malignant neoplasm believed to arise from notochordal remnants. It is most often found in the midline of the sacrococcygeal region (50%), skull base (35%), and the mobile spine (15%). When present in the sacral region, chordomas most often grow anteriorly. We present an unusual case of sacral chordoma with posterior extension.

CT presentation and staging accuracy of pancreatic adenocarcinoma.

In a retrospective study of 56 patients with surgically confirmed adenocarcinoma of the pancreas, the authors analyzed the efficacy of contrasted CT examination in the staging of tumor resectability and unresectability. Resectability was defined as strictly intrapancreatic disease; unresectability as locally invasive or metastatic disease. Of the 56 patients, 49 (88%) were found to be unresectable, and only seven (12%) were considered potentially resectable on the basis of CT evaluation. When these findings were compared to surgical findings, only one of the 49 CT unresectable patients was considered surgically resectable; all others showed advanced disease, with 30 of 49 (61%) having surgical findings comparable to CT findings, and 18 of 49 (37%) having more extensive disease at surgery than at CT. Of the 7 patients judged resectable by CT, only two (29%) were found to have local disease at surgery; three were locally invasive, one had positive nodes, and one had liver metastases. This study would suggest that CT can be very reliable in distinguishing advanced disease from confined intrapancreatic lesions (unresectability), but is not reliable for predicting locally confined disease (resectability). In particular, CT seems to be ineffective in demonstrating the full extent of pancreatic carcinoma, either unresectable or resectable, because of its inability to demonstrate microscopic local and nodal invasion and surface metastases.

Normal magnetic resonance anatomy of the tarsal tunnel.

Images of five cadaver ankles and three normal volunteers were obtained in an attempt to delineate magnetic resonance (MR) anatomy of the tarsal tunnel. Multiplanar T1-weighted (TE 20 msec, TR 600 msec) scans were obtained of the cadaver specimens while T1 and T2 weighted (TE 20, 80 msec, TR 2000 msec) scans were obtained of the volunteer ankles. After imaging, the cadaver ankles were frozen, sectioned, photographed, and compared to the MR images in the transverse plane. The anatomical structures seen on the MR images correlated closely with the cadaver sections. The bony and soft tissue boundaries and contents of the tarsal tunnel could be imaged with detail easily sufficient to delineate all the major structures within it, including the posterior tibial nerve and its branches.