Search PubMed⌕ Search

Biomedical subjects

K Hirohata

Publications and source records attributed to K Hirohata.

At least 73 records · Page 4Linked to original sources
PubMed1988

A clinicopathologic study of bony spurs on the pes anserinus.

Nineteen cases of exostoses located on part of the pes anserinus were studied clinically and histologically. All lesions were resected during surgery between 1965 and 1985. In these 19 cases, 14 had involvement of the tibia only at the insertion of the pes anserinus. Five had multiple exostoses with pes anserinus involvement. All exostoses occurring only in pes anserinus showed an icicle appearance in roentgenography and had no detectable cartilage cap. On the other hand, exostoses in patients with multiple exostoses (osteochondromas) showed varying appearances in roentgenography and had cartilage caps on their surfaces. Exostoses occurring only in the pes anserinus may or may not be osteochondromata and could be classified as pes anserinus bony spurs.

Adolescent↗
PubMed1988

An electron microscopic study of early pathology in chondromalacia of the patella.

For a study of the ultrastructural pathology of chondromalacia patellae, we studied biopsy specimens that had been obtained at operation in twelve young patients who had pain in the anterior aspect of the knee due to mechanical derangement and also had the pathological changes in articular cartilage that are characteristic of chondromalacia. The initial pathological finding was swelling of the superficial matrix associated with breakdown of the collagen fiber network, especially at matrix streaks in the superficial and transitional zones. Fibrillated cartilage contained surface fissures that penetrated the middle layers. Amorphous electron-dense material was found covering the internal surfaces of the fissures; this appeared to contain degraded components of the matrix. In association with these changes, there were formation of nests of cells (clusters of chondrocytes) and increased numbers of organelles in the chondrocytes. A limited repair reaction also was observed in some specimens; this was characterized by the migration of fibroblast-like cells over the surface of the cartilage. The ultrastructural observations on these specimens from patients who had chondromalacia were compatible with a pathogenesis resulting from mechanical overload.

Adolescent↗
PubMed1987

Changes in bone marrow blood flow with aging.

We investigated changes in bone marrow blood flow and histology with aging in rabbits. Bone marrow blood flow was measured by the hydrogen washout method, which was performed in the proximal tibia of Japanese white rabbits, 3-42 months of age. Bone marrow blood flow was found to decrease with age. Histological observations of the proximal tibia identified a decrease in the number of osteoblasts and hematopoietic cells, an increase of the number of empty lacunae, a reduction in bone formation rate, and a degeneration of marrow fat with aging. These results suggest that the decrease of bone marrow blood flow is related to histological changes found with aging.

Aging↗
PubMed1987

Dumbbell-shaped spinal extradural hemangioma.

A case of recurrent extradural cavernous hemangioma is presented. In contrast to secondary extension of a vertebral hemangioma to the epidural space, pure epidural hemangioma is rare. The location of this case was at the level of the 7th thoracic vertebra, and the tumor showed unusual dumbbell-like growth through an intervertebral foramen. The rarity of these lesions, as well as their clinical and radiological features, the diagnostic procedure, and the treatment are discussed.

Hemangioma, Cavernous↗
PubMed1987

Interaction of polymorphonuclear leukocytes with calcium pyrophosphate dihydrate crystals deposited in chondrocalcinosis cartilage.

Electron microscopy was used to investigate the characteristics of calcium pyrophosphate dihydrate (CPPD) crystals in chondrocalcinosis (pseudogout syndrome). Crystals in midzone cartilage were frequently seen adjacent to chondrocytes. Great variation in crystal size and shape was observed. Most of the pyrophosphate crystals that had been phagocytosed by polymorphonuclear leukocytes of synovial fluid from patients with acute pseudogout were small (less than or equal to 1 micron), indicating that small crystals can cause intense inflammation. Large numbers of polymorphonuclear leukocytes became attached to the eroded articular surface and phagocytosed microcrystals. Interaction of polymorphonuclear leukocytes with CPPD crystals in the superficial region of articular cartilage may stimulate the release of inflammatory mediators.

Aged↗
PubMed1986

An autoradiographic study of the distribution of sensory nerve endings in the knee joint of the rat.

The distribution of sensory nerve endings of the knee joint in rats has been investigated by autoradiography of 3H-leucine. Sections were made and each section was examined by autoradiography and silver impregnation staining. Free nerve endings were found only in the synovial membrane, the menisci and their synovial junction. In the joint capsule, capsulated sensory nerve endings were sparsely distributed. Numerous sensory nerve endings were found at the insertion of the patellar ligament, the collateral ligament and the cruciate ligament. These resembling Golgi-Mazzoni nerve endings or capsulated sensory nerve endings are thought to be proprioceptors. Radioactivity, which would indicate the presence of sensory nerve endings, was not recognized in the osseous tissue. It is hypothesized that proprioceptor at the insertion of ligaments plays an important role as monitor of joint motion by the reflex pathway.

Animals↗
PubMed1986

Long-term results of synovectomy in rheumatoid patients.

Seventy-eight knees in fifty-five rheumatoid patients were evaluated clinically and radiographically at an average of 14.1 years (range, ten to twenty-three years) after synovectomy. The functional result was excellent in seventeen, satisfactory in thirty-one, unsatisfactory in eighteen, and poor in twelve knees. Pain and recurrent effusions were significantly reduced after synovectomy, but the range of motion of the knee remained unchanged. Radiographs demonstrated progressive changes of degenerative joint disease but apparent arrest of inflammatory disease changes in about 67 per cent of the knees. We believe that synovectomy of the knee is a good treatment alternative for selected patients with early stage-I rheumatoid arthritis that has proved resistant to standard medical therapy.

Adult↗
PubMed1985

Old rupture of the patellar tendon. A case report.

A 46-year-old man with pain and instability in the right knee and a long-neglected rupture of the patellar tendon was treated by means of tendon reconstruction. External skeletal fixation between the patella and the tibial tubercle allowed for early exercise of the knee joint, resulting in a favorable range of knee motion. This method is considered to be helpful in the reconstruction of old and disabling patellar tendon ruptures.

Humans↗
PubMed1985

Steroid-induced accumulation of lipid in the osteocytes of the rabbit femoral head. A histochemical and electron microscopic study.

A high dose of methylprednisolone was administered intramuscularly to rabbits, and we studied the accumulation of lipid in the osteocytes of the femoral head by histochemical methods and electron microscopy. Advanced hyperlipidemia and a fatty liver were observed in four weeks. Electron microscopy was used to define the ultrastructural changes in osteocytes, which showed small lipid droplets that gradually enlarged, finally resulting in the formation of vacuolated vesicles. An increase in the size of the lipid droplets caused them to compress the nucleus to one side of the lacuna, resulting in discontinuities of the cell membrane followed by cell disintegration. These observations demonstrate the effect on osteocytes of a disturbance in lipid metabolism caused by the administration of large doses of steroids.

Animals↗
PubMed1984

Pathogenesis of chronic inflammation in experimental ferritin-induced arthritis. V. Electron microscopic localization of specific antibodies in the synovial membrane.

Antibody synthesis by the arthritic synovium of rabbits with antigen-induced arthritis has been demonstrated, but knowledge of the details of the specific localization of antibody in the membrane is limited. Specific antibody in the synovium of ferritin-induced arthritis was detected by electron microscopic observation of bound ferritin. The specific antibodies were localized in the cisternae of the endoplasmic reticulum and perinuclear spaces within plasma cells. In the extracellular matrix, specific antibody was found distributed as a network within collagen bundles and in the basement membrane of the subsynovial small blood vessels.

Animals↗