Biomedical subjects
M Schwimmer
Publications and source records attributed to M Schwimmer.
Synovial cysts of the knee: CT evaluation.
Eight patients with synovial cysts about the knee were studied by computed tomography (CT). Six of the eight patients had cysts in atypical locations, four medial and two anterior. Knee arthrography, performed on five patients, demonstrated the cyst in only two cases. In all patients CT defined the location and extent of the cyst, demonstrating the following benign features: a well-defined homogeneous mass with attenuation values approximating that of water, preservation of adjacent soft-tissue planes, and absence of bone involvement. The authors conclude that CT is useful in the evaluation of a suspected synovial cyst when its position is atypical or when arthrography fails to demonstrate or completely delineate the cyst. CT provided diagnostic accuracy and determination of the optimal operative approach.
Postoperative hysterosalpingogram: radiographic-surgical correlation.
The hysterosalpingograms of 46 patients who underwent previous uterine or tubal surgery were reviewed. Surgical procedures performed included cesarean section, myomectomy, uterine septal repair, tubal reimplantation and reanastomosis, and fimbrioplasty/cuff salpingostomy. The procedures and their resulting hysterosalpingographic appearances are discussed.
Cyclic adenosine 3':5-monophosphate receptor proteins in hormone-dependent and -independent rat mammary tumors.
The molecular species of cyclic adenosine 3':5'-monophosphate (cAMP) receptor proteins (high-affinity-binding proteins) present in hormone-dependent and -independent rat mammary carcinomas were identified and characterized. Three major types of cAMP receptor proteins, with molecular weights of 39,000, 48,000, and 56,000, specifically incorporated the photoaffinity label, 8-azido-cyclic adenosine 3':5'-[32P]monophosphate and were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the tumor cytosols. The M.W. 48,000 and 56,000 receptor proteins appeared to be the regulatory subunits of cAMP-dependent protein kinase types I and II, respectively, and the M.W. 39,000 receptor protein was the proteolytic fragment of the M.W. 56,000 receptor protein. The relative amounts of these cAMP receptor proteins varied from one tumor type to another and showed no correlation with respect to the hormone dependency of tumors. Under two-dimensional gel electrophoresis, however, the M.W. 56,000 receptor protein from hormone-dependent tumors migrated as a doublet and shifted to either a more acidic or more basic charge than that of the receptor protein of hormone-dependent tumors. The alteration of the charge of the receptor did not affect the affinity for cAMP binding, because both hormone-dependent and hormone-independent tumor cytosols exhibited the dissociation constant for cAMP of approximately 10(-8) M. The M.W. 56,000 cAMP receptor protein from hormone-dependent tumors exhibited self-phosphorylation, but that from hormone-independent tumors did not. The diethylaminoethyl cellulose elution profiles of cAMP receptor proteins also differed between hormone-dependent and -independent tumors; cAMP binding activity from hormone-dependent tumors coeluted with cAMP-dependent protein kinase activity, whereas most of the cAMP binding activity from hormone-independent tumors eluted at a higher ionic strength than did cAMP-dependent protein kinase activity. These results suggest that the charge alteration of cAMP receptor proteins, which appears to occur at a site remote from that of cAMP binding, may be associated with the hormone independency of mammary tumors.
Probabilistic behavior of DNA segregation in Escherichia coli.
The pattern of segregation of DNA in Escherichia coli B/rK was analyzed by using the Methocel technique for forming chains of cells and the membrane binding elution method. Strain B/rK was shown to have a relatively high degree of nonrandom segregation and was used in a critical experiment to test the proposal that only one DNA strand acts nonrandomly during segregation. Thymidine-labeled cells were bound to a nitrocellulose membrane, and newly dividing cells were eluted from the membrane for six generations. The segregation of DNA in the eluted cells as well as in the cells bound to the membrane was examined by the Methocel technique. No difference in segregation was found between the two populations of cells, a result which indicates that the two strands are equivalent in segregation and that the pattern of segregation is not the result of a permanent binding of any strand to a pole of a cell.