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Biomedical subjects

G Niwayama

Publications and source records attributed to G Niwayama.

At least 37 records · Page 2Linked to original sources
PubMed1977

The sesamoid bones of the hands and feet: participators in arthritis.

The sesamoids generally appear as small ovoid bones adjacent to articulations or at sites where tendons are angled about osseous surfaces. At either location they participate in joint afflictions, the pattern of abnormality being remarkably constant and predictable. Sesamoids may demonstrate osseous erosion in rheumatoid arthritis, bony proliferation or "whiskering" in rheumatoid variants, joint space narrowing and bony ankylosis in septic arthritis, and eburnation and osteophyte formation in osteoarthritis and diffuse idiopathic skeletal hyperostosis. These changes become particularly important when they occur in the absence of significant adjacent articular disease. In these instances, recognition of sesamoid abnormalities allows accurate radiographic diagnosis.

Arthritis↗
PubMed1977

Intra-articular calcification in scleroderma.

Two patients with scleroderma demonstrated intra-articular calcification, which is rarely observed in this disease. The authors suggest that intra-articular calcification and erosion of adjacent cartilage and bone are related.

Adult↗
PubMed1977

Calcaneal abnormalities in articular disorders. Rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and Reiter syndrome.

The calcaneus of normal control patients, and those with rheumatoid arthritis, ankylosing spondylitis, psoriasis, and Reiter syndrome was studied. Pathological abnormalities of the plantar aponeurosis, Achilles tendon, and retrocalcaneal bursa account for the radiographic alterations. In normal individuals, lateral radiographs show the thickness of the Achilles tendon to be not greater than 8 mm; the retrocalcaneal bursa creates a radiolucency which extends at least 2 mm below the superior surface of the calcaneus. In patients with any of these 4 articular disorders, Achilles tendinitis produces thickening of the tendon, and retrocalcaneal bursitis obliterates the normal radiolucency.

Adult↗
PubMed1977

Comparison of radiographic abnormalities of the sacroiliac joint in degenerative disease and ankylosing spondylitis.

Degenerative disease of the sacroiliac joint is common in middle-aged and elderly patients. Its radiographic features simulate those of ankylosing spondylitis. Interosseous space narrowing, subchondral sclerosis, and osteophytosis are apparent. Although intraarticular bony ankylosis is generally absent, anterior paraarticular bridging osteophytes resemble true osseous fusion of the joint cavity on frontal radiographs. Focal sclerosis in degenerative disease is most common on the superior and inferior margins of the articular cavity and can usually be differentiated from that accompanying ankylosing spondylitis and osteitis condensans ilii.

Adult↗
PubMed1977

Subchondral cysts (geodes) in arthritic disorders: pathologic and radiographic appearance of the hip joint.

A comprehensive study of femoral heads of patients and cadavers with osteoarthritis, rheumatoid arthritis, osteonecrosis, and calcium pyrophosphate dihydrate deposition disease allows insight into the radiographic and pathologic appearance of subchondral radiolucencies in these disorders. The term geode, rather than cyst or pseudocyst, may be a more appropriate decription of these lesions. In osteoarthritis, goedes occur on the pressure segment of the femoral head in association with loss of articular space; in rheumatoid arthritis, they are initially noted at the chondro-osseous junction and subsequently involve the entire femoral head. In osteonecrosis, geodes appear in the necrotic segment of the femoral head. In calcium pyrophosphate deposition disease, geodes resemble those in osteoarthritis but are larger, more numerous, and more widespread.

Arthritis↗
PubMed1977

Angiographic aspects of experimental nonocclusive intestinal ischemic injury.

An experiment was designed to fulfill the following aims: (1) to develop a model of nonocclusive intestinal ischemic injury compatible with survival for several days; (2) to determine the accuracy of angiography in diagnosing the presence and extent of intestinal ischemic injury; and (3) to determine the therapeutic and diagnostic value of intraarterial papaverine infusion. Experimental shock models were developed in the dog, and efficacy of the hypovolemic and normovolemic models was confirmed by gross and histologic evidence of intestinal injury in surviving dogs. No reliable angiographic signs of intestinal mucosal injury could be elicited. Angiographic abnormalities associated with the experiment were attributable to the shock itself and disappeared with the relief of shock. Infusion of papaverine into the superior mesenteric artery within 2 hr of the onset of shock prevented or ameliorated intestinal injury.

Angiography↗
PubMed1977

On the nature and significance of bony proliferation in "rheumatoid variant" disorders.

Radiographic and pathologic abnormalities of the peripheral joints in a cadaver with ankylosing spondylitis are described. Bony proliferation about involved articulations is is characteristic of all "rheumatoid variant" disorders and results from subchondral bony hyperplasia and periosteal new bone formation. Such proliferation may be related to the presence of the histocompatibility antigen B27 in these diseases.

Arthritis, Rheumatoid↗
PubMed1976

Subchondral resorption of bone in renal osteodystrophy.

In a radiographic-pathologic study of the spine and several axial joints in a cadaver with renal osteodystrophy, subchondral resorption of bone is described as an important mechanism of osseous abnormality. Widening and irregularity of the sacroilliac and sternoclavicular joints and symphysis pubis are related predominantly to trabecular destruction beneath cartilage surfaces, substitutive fibrosis, and new bone formation. Subperiosteal abnormalities at these locations produce juxta-articular erosions. The presence of osteitis fibrosa cystica about multiple Schmorl's nodes within the thoracic vertebral bodies suggests that subchondral resorption beneath the cartilage end-plates of the spine may be associated with disk protrusions and represents one further example of hyperparathyroid joint disease.

Aged↗
PubMed1976

Radiographic and pathologic features of spinal involvement in diffuse idiopathic skeletal hyperostosis (DISH).

The vertebral involvement of DISH is described from an evaluation of 215 cadaveric spines and 100 patients with the disease. Radiographic features include linear new bone formation along the anterolateral aspect of the thoracic spine, a bumpy contour, subjacent radiolucency, and irregular and pointed bony excrescences at the superior and inferior vertebral margins in the cervical and lumbar regions. Pathologic features include focal and diffuse calcification and ossification in the anterior longitudinal ligament, paraspinal connective tissue, and annulus fibrosis, degeneration in the peripheral annulus fibrosis fibers, L-T-, and Y-shaped anterolateral extensions of fibrous tissue, hypervascularity, chronic inflammatory cellular infiltration, and periosteal new bone formation on the anterior surface of the vertebral bodies.

Cervical Vertebrae↗
PubMed1976

Resorption of the undersurface of the distal clavicle in rheumatoid arthritis.

An elongated erosion on the undersurface of the distal clavicle, adjacent to the coracoid process, may be seen in the shoulder of a patient with rheumatoid arthritis. This finding is apparently related to inflammatory changes in the coracoclavicular ligament. Such an erosion may occur with or without additional radiographic alterations and, although not entirely specific, suggests rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1976

Bilateral pulmonary hilar lymphadenopathy. An unusual manifestation of metastatic renal cell carcinoma.

Four patients with bilateral pulmonary hilar adenopathy secondary to lymphangitic spread from renal cell carcinoma were examined. Two additional cases had adenopathy secondary to nasopharyngeal carcinoma. Patients may initially present with bilateral pulmonary lymphadenopathy or as late as 3 1/2 years after the discovery of the primary renal tumor. The mechanism of lymphangitic spread probably is related to reflux of tumor emboli from the thoracic duct into the bronchomediastinal trunks because of incompetent lymphatic valves. In one case gallium imaging demonstrated bilateral hilar isotopic uptake as well as periaortic uptake.

Adenocarcinoma↗
PubMed1976

Comparison of androgen metabolites in benign prostatic hypertrophy (BPH) and normal prostate.

5 alpha-Dihydrotestosterone (DHT) and androstanediols (diols) have been measured in human prostate tissue. DHT levels in surgical specimens of prostate from 8 patients with BPH averaged 5.6 +/- 0.93 S.E. ng/g and were significantly greater than (P less than 0.01) values of 2.1 +/- 0.32 S.E. ng/g in 6 normal prostates obtained post-mortem from males less than 50 yrs old. Androstanediols averaged 2.3 +/- 0.35 S.E. ng/g in the BPH specimens compared to values of 10.2 +/- 2.4 S.E. ng/g in the normal prostates (P less than 0.01). This significantly higher (P less than 0.001) ratio of diols/DHT in the normal (5.1 +/- 0.93 S.E.) compared to the BPH prostate (0.45 +/- 0.08 S.E.) suggests that a decrease in 3-hydroxysteroid oxido-reductase, which converts DHT to diol, may be an important clue to the pathogenesis of BPH.

Androstane-3,17-diol↗
PubMed1976

Localized nodular synovitis of the knee: a report of two cases with abnormal arthrograms.

The arthrographic appearance in two cases of localized PVS of the knee involving the region of the infrapatellar fat pad is reported. Lesions in this area may present with confusing symptomatology, and the true abnormality may be overlooked in a search for meniscal lesion. The arthrographic picture is non-specific and a number of entities must be considered.

Adolescent↗
PubMed1975

Functional evaluation of the porcine heterograft in the mitral position.

In vivo function of glutaraldehyde-fixed porcine heterografts used for mitral valve replacement was evaluated by cardiac catheterization in 14 of our first 33 patients who have undergone mitral valve replacement with this prosthesis. Diastolic gradients were present in each patient. Average mean diastolic gradient was 6.5 mm Hg for the group, and average end-diastolic gradient was 3.0 mm Hg. Calculated mitral valve orifice areas ranged from 0.92 cm2 to 3.39 cm2, the average being 2.15 cm2. With rapid pacing (heart rate approximately 140), average mean gradient increased by 6 mm Hg. No patient had mitral regurgitation. Two patients had calculated mitral valve areas of 1 cm2 or less; one of these was found at postmortem examination to have thrombus adherent to the ventricular aspect of 2 of the 3 valve leaflets, rendering them immobile.

Adult↗
PubMed1975

Sacro-iliac joint in renal osteodystrophy: roentgenographic-Pathologic correlation.

A detailed roentgenographic and pathologic study of the sacro-iliac joint in a cadaver with renal osteodystrophy revealed subchondral abnormalities, particularly in the ilium, which consisted of resorption of bone, substitutive fibrosis, and thickening of remaining trabeculae. Overlying articular cartilage degeneration was also apparent. The "pseudo-widening" of the joint space noted in ante and post-mortem radiographs in this patient simulated the findings in early ankylosing spondylitis.

Aged↗
PubMed1974

Combined immunodeficiency presenting as the Letterer-Siwe syndrome.

Four infants with skin rash, hepatosplenomegaly, lymphocytosis, eosinophilis, and histiocytic infiltration of the lymph nodes and skin are described; in each of these infants an initial diagnosis of the Letterer-Siwe syndrome was made. Postmortem findings of thymic dysplasia and poorly differentiated, lymphopenic peripheral lympoid tissue in each of the four infants, as well as antimortem clinical findings in one, established a diagnosis of severe combined immunodeficiency. From these and similar cases in the literature, we postulate that the Letterer-Siwe syndrome may not be an unusual presentation of combined immunodeficiency. Appropriate immunologic studies will help to differentiate the two disorders.

Autopsy↗