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Biomedical subjects

T Yamashima

Publications and source records attributed to T Yamashima.

At least 91 records · Page 5Linked to original sources
PubMed1989

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.

Adolescent↗
PubMed1989

Ultrastructural immunogold labelling of vimentin filaments on postembedding ultrathin sections of arachnoid villi and meningiomas.

An immunoelectron microscopic technique for the labelling of vimentin intermediate filaments on postembedding ultrathin sections is reported. Arachnoid villi obtained at autopsy and meningiomas at surgery were fixed in 1% paraformaldehyde for 30 minutes, embedded without postfixation in Epon-Araldite mixture and polymerized at 37 degrees C for 3 weeks. Ultrathin sections were etched in 2% KOH for 3 minutes and incubated with anti-vimentin monoclonal antibodies which were subsequently labelled with goat anti-mouse IgG coupled to colloidal golds. All of these labelling procedures were consistently performed within 4 hours. In both arachnoidal and meningioma cells, immunogolds preferentially decorated the intermediate filaments in proportion to the concentration. Very few gold particles were seen over the nucleus, Golgi zone, mitochondria and the extracellular connective tissue fibres. The present technique may be applied to the immunogold labelling of intermediate filaments on postembedding ultrathin sections.

Antibodies, Monoclonal↗
PubMed1989

Enlarging fundal hemorrhage in Terson's syndrome.

Serial photographs of an enlarging fundal hemorrhage were taken in a 44-year-old man with a subarachnoid hemorrhage. Although clipping surgery was done successfully 17 hours after onset, the patient developed impaired vision on the third postoperative day. Funduscopic examination can document the exact moment when enlarging subhyaloid hemorrhage extends into the vitreous cavity.

Adult↗
PubMed1988

Immunohistochemical study of folliculo-stellate cells in human pituitary adenomas.

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.

Adenoma↗
PubMed1988

Reconstruction of surgical skull defects with hydroxylapatite ceramic buttons and granules.

This paper is to report a new method of reconstructing surgical skull defects with hydroxylapatite ceramics. The latter consist of Ca10(PO4)6(OH)2 which has a biological affinity with mammalian bone minerals. The author has designed two cranioplastic materials using hydroxylapatite ceramics: apatite buttons for burr hole skull defects and apatite granules for linear skull defects. The bone defects during 100 cases of standard craniotomy were successfully reconstructed with these materials with satisfactory cosmetic results. Hydroxylapatite ceramics are characterized by the excellent biocompatibility and biostability with a resultant bony fusion.

Aged↗
PubMed1988

Functional ultrastructure of cerebrospinal fluid drainage channels in human arachnoid villi.

The functional ultrastructure of the human arachnoid villi was studied to clarify drainage channels of cerebrospinal fluid (CSF). The apical portion of each villus was usually covered by the arachnoid cell layer alone with no endothelial investment, whereas most of the stromal central core was further encompassed by a fibrous capsule with an endothelial investment. Accordingly, the CSF-blood interface was assumed to be in both the endothelial cells and the arachnoid cell layer. The former were characterized by abundant micropinocytotic vesicles and occasional intracytoplasmic vacuoles, whereas the latter was characterized by numerous extracellular cisterns measuring 10 micron in maximal diameter. There were no free communications such as endothelial open junctions or endothelium-lined tubules. In the villi affected by subarachnoid hemorrhage, endothelial cells were intact and continuous despite the erythrocyte-packed subendothelial space, which appeared to be on the verge of rupturing. Intracytoplasmic vacuoles, measuring less than 1 micron diameter, sometimes contained serum protein-like substance. Furthermore, the extracellular cisterns were distended by intact or disintegrating erythrocytes that served as a natural tracer, suggesting CSF drainage channels. It is conceivable that, in human arachnoid villi, the extracellular cisterns of the arachnoid cell layer contribute to the passive transport of CSF, whereas micropinocytosis and vacuolization mechanisms of the endothelial cells are available for active transport.

Adolescent↗
PubMed1988

A light and electron microscopic and immunohistochemical study of human arachnoid villi.

The structure of human arachnoid villi was investigated by light and electron microscopy with the aid of immunohistochemical techniques. The human arachnoid villi examined were basically composed of four portions: a fibrous capsule, an arachnoid cell layer, a cap cell cluster, and a central core. The arachnoid cell layer encompassing the central core was mostly covered by the thin fibrous capsule with an endothelial investment. However, the fibrous capsule was often absent at the apical portion of the villus and a factor VIII-related antigen stain failed to confirm the investment of endothelial cells. Instead, the arachnoid cell layer abutted directly upon the lumen of a lateral lacuna or the sinus. The arachnoid cell layer was thickened in places, forming cap cell clusters; it usually consisted of outer and inner zones. On vimentin staining, the former was slightly positive while the latter was strongly positive. The central core contained a network of arachnoid cells intermingled with connective tissue fibers and was in continuity with the cranial subarachnoid space. Electron microscopy showed that the arachnoid cells contained a larger number of intermediate filaments in the inner zone than the outer zone. Ultrastructural immunohistochemical localization showed that vimentin was localized at the intermediate filaments and desmosomal plaques of the arachnoid cells. The arachnoid cells showed a marked variety in both the cell forms and the number of intermediate filaments or desmosomes, depending on their location.

Adolescent↗
PubMed1988

Previously unreported "hemidesmosomal junctions" between folliculo-stellate cells and pituitary adenoma cells.

Thirty-eight non-functioning pituitary adenomas were ultrastructurally investigated with particular attention to the Folliculo-Stellate (FS) cells. A large number of FS cells were found in four cases, one of which disclosed a new type of intercellular junction between FS cells and surrounding adenoma cells. These junctions were characterized by 1) the presence of plasmalemmal attachment plaques only in FS cells, 2) the cytoplasmic filaments assembling in parallel to the attachment plaques, 3) the parallel plasma membranes being separated by the intercellular amorphous material and 4) the intercellular space of approximately 25 nm width. They were similar to hemidesmosomes, but were quite different from hemidesmosome-like intercellular specializations which have been described in the normal meninges and human meningiomas. Accordingly, we designated these new junctions as "hemidesmosomal junctions" which appeared to be one of the ultrastructural features characterizing FS cells.

Adenoma↗
PubMed1988

[A case of von Hippel-Lindau disease associated with bilateral renal cell carcinoma].

A case of von Hippel-Lindau disease associated with bilateral renal cell carcinoma is presented. A 27-year-old female noticed myodesopsia and underwent laser coagulation of right retinal hemangioma in 1973. In addition, cerebellar hemangioblastomas were removed in 1977, 1978, 1983 and 1987. The patient was referred to the department of urology for further examination of bilateral renal masses which were incidentally found on abdominal computed tomography (CT) and magnetic resonance-CT. Fine needle biopsy performed and microscopic examination revealed the presence of clear cell type renal cell carcinoma (grade 1). Renal arteriography demonstrated multiple neovascularity in the bilateral masses. Complete tumor excision was impossible to retain the minimum of renal function, the patient was conservatively subjected to a follow-up study.

Adult↗
PubMed1988

Ultrastructural comparison of arachnoid villi and meningiomas in man.

An ultrastructural comparison of arachnoid villi and meningiomas was made in man. Human arachnoid villi basically consisted of four portions: fibrous capsule; arachnoid cell layer; cap cell cluster; and central core. Arachnoid cells had many characteristic structures in common with meningioma cells: plasmalemmal interdigitations; desmosomes; hemidesmosome-like junctions; and cytoplasmic filaments. Both arachnoid villi and meningiomas were characterized by the numerous extracellular cisterns which appeared to form outflow channels of cerebrospinal or serum fluid. Differences between arachnoid villi and meningiomas pertained to cytoplasmic components reflecting the states of permeability of endothelial cells, junctional complexes, and matrix substances of psammoma bodies. Endothelial cells investing the fibrous capsule contained a number of micropinocytotic vesicles and intracytoplasmic vacuoles, but showed no fenestrations. In contrast, meningiomas not only contained numerous micropinocytotic vesicles and intracytoplasmic vacuoles but also exhibited numerous fenestrations. Furthermore, there were a larger number of junctional complexes between arachnoid cells than meningioma cells. Arachnoid villi contained abundant matrix granules while meningiomas contained only a few matrix granules but a larger number of matrix minerals and vesicles, as the presumptive precursors of psammoma bodies.

Adolescent↗
PubMed1987

Fine structure of myonecrosis following adrenalin-induced cerebral vasospasm.

Frank necrosis of the media (myonecrosis) which could be confirmed by light microscopy was previously produced by the authors after the injection of adrenalin into the canine chiasmatic cistern. It is the purpose of this paper to report ultrastructural features of myonecrosis following adrenalin-induced cerebral vasospasm. The latter was induced in 10 dogs by a single subarachnoid injection of 0.2 mg/kg of adrenalin. Two dogs died of cerebral vasospasm 3 and 6 days respectively after the experiment, whereas eight other dogs were killed between 2 and 90 days. Microscopically, the circle of Willis showed coagulation necrosis and fibrosis of the media. The fine structure of myonecrosis was characterized by six dynamic changes of vacuolation, dissolution of myofilaments, focal cytoplasmic necrosis, fragmentation, coagulation necrosis and intercellular fibrosis. Despite a simple experimental procedure, the present models disclosed myonecrosis with a marked similarity to humans and contained all of the previously reported ultrastructural features of experimental myonecrosis. It is suggested that sustained contraction of smooth-muscle cells beyond their metabolic capability results in the mechanical destruction of myofilaments.

Actin Cytoskeleton↗
PubMed1987

Numerous Weibel-Palade bodies in a calcified chronic subdural haematoma.

A 75-year-old man who had a calcified chronic subdural haematoma is reported with reference to the role of Weibel-Palade (W-P) bodies. He developed progressive dementia and a disturbance of gait. Computerized tomography demonstrated a large subdural haematoma bordered by a calcified rim. A frontoparietal craniotomy was performed to reveal approximately 100 g of paste-like, muddy blood clot. The thick capsule consisted microscopically of fibrous tissue with deposits of calcium, haemosiderin and cholesterin. The calcified outer membrane contained a small number of proliferating capillaries which conceivably contributed to the leakage of blood. The fine structure of these capillaries showed endothelial sprouts with numerous W-P bodies. This finding suggested some correlation between W-P bodies and vascular proliferation. It is noteworthy that an active vascular proliferation was observed even in the healed tissue with calcification.

Aged↗
PubMed1987

Ultrastructural study of calcification process in the ligamentum flavum of the cervical spine.

The ultrastructure of the formation of calcified nodules in three cases of symptomatic calcification of the cervical ligamentum flavum were studied. In some areas of the ligament, extracellular plasma membrane-invested matrix vesicles and thick wall-bound matrix giant bodies with or without mineralized deposits were present. These calcified vesicles and bodies were also encountered in the wide mineralized areas among the collagen and elastic fibers in the ligament. The mineralization process of the calcified nodules in the ligamentum flavum implies that matrix vesicles and matrix giant bodies acquire mineralized precipitates; then some gather in clusters. Calcified deposits may spread to collagen and elastic fibers contiguous with the calcified vesicles and bodies, and some eventually coalesce to make a calcified nodule.

Aged↗