Mesenchymal chondrosarcoma of the ethmoid sinus

Mesenchymal chondrosarcoma arising from primitive mesenchymal cells is a distinctive type of chondrosarcoma that exists in both skeletal and extraskeletal forms. The tumor is composed of undifferentiated cells with focal areas of cartilaginous or chondroid matrix. An extremely rare case of mesenchymal chondrosarcoma of the anterior and middle ethmoid sinuses in a 16-year-old girl is presented. Magnetic resonance imaging provided more anatomic information about the tumor than computerized tomography and aided in surgical planning.     

Cranioplasty with hydroxylapatite ceramic plates that can easily be trimmed during surgery

Summary The author has designed new cranioplastic materials to reconstruct a skull defect of moderate size in both the convexity and the suboccipital region. A domed and elliptic plate measuring 50×75 mm in diameter, 12 mm in the maximum height and 5 mm in thickness was made from hydroxylapatite ceramics. The latter comprise Ca₁₀(PO₄)₆(OH)₂ as mammalian bone minerals and are characterized by an excellent biocompatibility and biostability resulting in bony fusion. Hydroxylapatite ceramic plates can be easily trimmed during surgery to closely fit the skull defect. There were no adverse reactions nor resorption of the implants.     

Anatomical variations of the straight sinus on magnetic resonance imaging in the infratentorial supracerebellar approach to pineal region tumors.

Anatomical variations of the straight sinus (SS) were examined on magnetic resonance imaging (MRI) in 108 control cases and five cases with a pineal region tumor. The data of the latter were compared with the operative findings in the infratentorial supracerebellar approach. In the 108 control cases, the length of the SS was 51 +/- 5.2 mm. The angle of the SS to the nasion-tuberculum sellae line, the tuberculum sellae-inion line, and the nasion-inion line was 51 +/- 6.7 degrees, 44 +/- 5.0 degrees, and 47 +/- 5.0 degrees, respectively. The SS was inclined 1.4 +/- 4.5 degrees posteriorly to the bregma-inion line. The anatomical relationship between the SS and the corpus callosum was subgrouped into three types: in the common type (63%), the extended line of the slope of the SS is tangential to the upper aspect of the splenium of the corpus callosum; in the high-angle type (26%), the extended line is far above the tangent line; and in the low-angle type (11%), the extended line is far below the tangent line. The operative field was restricted by the steeply inclined tentorium in the case of the high-angle type, and the tumor was located much lower than the direction of the operative approach. In contrast, the tumor was easily exposed in the center of the wide operative field in the cases of low-angle type. The present study suggests that the preoperative MRI analysis of the angle of the SS is indispensable before taking the infratentorial supracerebellar approach to the pineal region tumors.     

An electron microscopic study of cerebral vasospasm with resultant myonecrosis in cases of subarachnoid haemorrhage,meningitis and trans-sylvian surgery

Summary Electron microscopic data on the development of myonecrosis following cerebral vasospasm associated with subarachnoid haemorrhage, meningitis and trans-sylvian surgery are presented. The basic feature of myonecrosis was dissolution of myofilaments with resultant fine granular or filamentous material. The disintegrating cytoplasm often contained numerous glycogen granules, dense bodies, autophagic vacuoles and myelin-like membranous bodies. A well-developed sarcoplasmic reticulum was preserved despite myofilament dissolution, while mitochondria showed marked sweling. The nuclei showed either dilution of chromatin or pyknotic change. The basal lamina was remarkably thickened and maintained an irregular outline of the necrotic smooth muscle cells. Enlarged intercellular space contained abundant cellular debris, vesicular structures and connective tissue fibres. The pathogenesis of these changes is discussed.     

Immunohistochemical study of folliculo-stellate cells in humna pituitary adenomas

Summary Folliculo-stellate (FS) cells were studied in 102 human pituitary adenomas by immunohistochemical techniques using antibodies to S-100 protein and intermediate filaments protein. In most pituitary adenomas there were few S-100-positive cells, in contrast, numerous FS cells were found in four of the 54 cases of non-functioning adenomas. Among glial fibrillary acidic protein (GFAP), keratin and vimentin, FS cells showed greatest affinity to vimentin. Stains for desmin or neurofilaments were always negative. Counterstains with GFAP and keratin could demonstrate a small number of double-labelled cells, but mainly disclosed two types of FS cells positive for either GFAP or keratin. Accordingly, FS cells were grossly subdivided into two types: GFAP-positive cells which might be neuroectodermal or glial in origin and keratin-positive cells which might be oral ectodermal or derive from the Rathke's pouch.     

Histological,ultrastructural and chromatographical discrimination of phospholipids in meningiomas

Summary Phospholipids in meningiomas were studied by light and electron microscopy, and by high-performance liquid chromatography. They were microscopically demonstrated in six of the ten cases by Sudan III staining after the fixation with potassium dichromate. However, the conventional ultrastructural fixation with glutaraldehyde and osmium tetroxide failed to confirm phospholipids, as most of them were dissolved during dehydration. In contrast, the specimens pretreated with tannic acid before osmication ultrastructurally retained phospholipids which were represented by multilamellar bodies or ribbon-like rings. Both were found in 23 of the 30 cases within the cytoplasm, among the plasma membranes and in the extracellular matrices. The outermost lamella or ribbon showed a direct continuity from the neighbouring plasma membranes of the cytoplasm or the mitochondria. The multilamellar bodies showed an overall distribution, while the ribbon-like rings were predominantly distributed around the psammoma bodies. Precipitation of hydroxyapatite crystals within the ribbon-like rings resulted in matrix minerals of psammoma bodies. Chromatographical analyses of meningiomas disclosed phospholipids including phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, sphingomyelin and phosphatidyl inositol in that order. Psammomatous meningiomas contained a higher percentage of phosphatidyl serine than non-psammomatous tumors. Ultrastructural study of synthetic phospholipids adequately treated with tannic acid showed that the multilamellar bodies were similar to phosphatidyl choline, while the ribbon-like rings were similar to phosphatidyl serine. The role of phospholipids in meningiomas is discussed.     

Postictal blockade of ischemic hippocampal neuronal death in primates using selective cathepsin inhibitors

This paper is to study the participation of cathepsin in ischemic neuronal death of the monkey hippocampal cornu ammonis (CA) 1 sector and also to clarify whether its selective inhibitor epoxysuccinyl peptides such as CA-074 and E-64c can inhibit the neuronal death or not. In the preceding reports, we demonstrated mu-calpain activation and subsequent rupturing of the lysosomal membrane of postischemic CA1 neurons and also increase of enzyme activity of cathepsins B and L in monkeys undergoing a complete 20-min whole brain ischemia. Here, morphological, immunohistochemical and enzymatical analyses were performed to examine the efficacy of two selective cathepsin inhibitors in the postictal blockade of delayed neuronal death in the monkey hippocampus. Both inhibitors could significantly decrease enzyme activities of cathepsins B and L in all hippocampal sectors. When CA-074 was intravenously administered immediately after the ischemic insult, approximately 67% of CA1 neurons were saved from delayed neuronal death on day 5 after ischemia. In contrast, when E-64c was similarly administered, approximately 84% of CA1 neurons were saved from delayed neuronal death on day 5. The surviving neurons showed mild central chromatolysis and negligible immunoreactivity for cathepsins B and L. These observations indicate that the use of cathepsin inhibitors may become novel strategy for prevention of ischemic delayed neuronal death in the primate hippocampus.     

Meningothelial rosettes in the canine subarachnoid space

Summary A previously unrecognized type of rosette consisting of meningothelial cells is reported. Meningothelial clusters with a formation of numerous rosettes were incidentally observed in the canine subarachnoid space after single subarachnoid, injection of 0.2 mg/kg of epinephrine. Light microscopy revealed that the cell clusters with distinct rosettes occurred in the extensive cords and nests, surrounding the small subarachnoid arteries or adhering to the arachnoid epithelium. There were scattered mast cells adjacent to the cell clusters. Electron microscopy revealed that the resettes usually consisted of four to 12 tightly packed cells which were arranged like spokes and contained concentrations of tonofilaments. The rosette cells were knitted together by numerous junctional devices, such as desmosomes and desmosome-like junctions as well as a small number of interdigitations at the lateral surfaces toward the central core. The latter measured approximately 0.77–12.72 m in long diameter, containing electrondense, coarsely granular material. Both intracytoplasmic and extracellular inclusions with projecting microvilli were reminiscent of hyaline inclusions in certain meningiomas.