Paraganglioma of the cauda equina with associated intramedullary cyst: MR findings.

The MR imaging features of a paraganglioma of the cauda equina with associated spinal cord cysts are presented. MR imaging showed the tumor to be isointense with the spinal cord on all pulse sequences and to enhance homogeneously. The intramedullary cysts had increased signal intensity on proton density- and T2-weighted images, and involved the cervical and thoracic regions.     

Malignant fibrous histiocytoma of the temporal bone with endocranial extension.

Cranial malignant fibrous histiocytomas are rare tumors. Most are hypervascular, destructive masses that are similar to other malignant lesions and to malignant fibrous histiocytomas found elsewhere in the body. We describe a myxoid malignant fibrous histiocytoma of the temporal bone, possibly of dural origin, with features that more closely resembled a meningioma at CT, MR imaging, and angiography.     

Deep Granuloma Annulare (Pseudorheumatoid Nodule) in Children: Clinicopathologic Study of 35 Cases

Deep granuloma annulare (DGA) is one of several lesions of skin and superficial soft tissues whose histologic character is a palisading granuloma with a small central focus of necrosis or necrobiosis. Unlike the other palisading necrobiotic lesions, DGA has a predilection for children in the first 5 to 6 years of life. A painless subcutaneous nodule(s) in the lower anterior tibial region or foot and the scalp, typically in the occiput, was the most common presenting feature in this study of 35 cases. Additional or recurrent lesions were reported in approximately 70% of cases with clinical follow-up. All lesions showed the presence of necrobiosis; however, one of the characteristic features was the multinodular character of the predominantly mononuclear cellular aggregates. The presence of vascular spaces at the periphery of the nodular profiles served as a clue to the diagnosis of DGA. The palisading arrangement of the mononuclear cells was evident only in those foci with central necrobiosis. A histiocytic disorder or fibrohistiocytic process was a common consideration in the differential diagnosis, especially in those cases with less apparent foci of necrosis. Palisading histiocytes with prominent eosinophilic cytoplasm and some nuclear atypism were problematic with regard to possible epithelioid sarcoma. Our study failed to identify any underlying or predisposing factors in the development of DGA. Despite the fact that DGA is a well-documented lesion in children, it occurs sufficiently infrequently that it is often not considered clinically when it presents as a subcutaneous mass or masses in a child. Its recognition by the pathologist is especially important as the occurrence of additional lesions in a high proportion of children can be anticipated without undue concern. Received June 16, 1997; accepted October 28, 1997.     

Rheo-optical fourier transform infrared spectroscopy of polyurethanes and their blends with polyolefins

Rheo-optical Fourier transform infrared spectroscopy was used to analyze the orientational behavior of hard and soft segments of thermoplastic poly(ether urethane)s (TPU-Et) and poly(ester urethane)s (TPU-Es) and their blends with a 20 mass-% contribution of either polyethylene (PE) or polypropylene with an amorphous rubber phase (PP). The blends show a reduced stress level, lower elongation-to-break and a lower degree of orientation of the segments — especially for the TPU-Es blends — compared to those of pure TPU's when uniaxially elongated. Blends of TPU-Et with PP show reduced stress but increased strain compared to pure films of TPU-Et. This is caused by an improved adhesion of the rubber phase in the polypropylene and the polyether phase of TPU-Et. Optical micrographs visualize deformed polyolefin particles in elongated films of TPU-Et/PP blends. In the TPU-Et/PP blend we could achieve equivalent orientation for the polyolefin phase and the segments of TPU-Et caused by this higher phase adhesion compared to the other blends. Orientation functions (OF's) of absorption bands which specifically represent hard or soft polyurethane segments or which are characteristic of the polyolefin phase have been calculated to monitor the molecular alignment due to the mechanical treatment.     

Pharmacokinetics of orally administered norethisterone enanthate in rabbit, monkey, and women

Norethisterone enanthate (NET-En), an established intramuscular long-acting contraceptive agent, has previously been shown to be effective in inhibiting fertility in two rodent species even 4 days after oral ingestion. Pharmacokinetics of NET and NET-En were studied after oral and intramuscular doses in two animal species and a few women. The results suggest that the NET-En was absorbed within a day in all the species after oral dose. The estimates of relative bioavailability ranged from 13 to 51% in rabbits, monkeys, and women. The elimination half-life was 5–10 days. The presence of the active component, NET, in the circulation over the experimental period of 15 days suggests that NET-En could be useful as a long-acting oral pill. The suppression of progesterone levels during the luteal phase of menstrual cycle in women also supports this finding.