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Biomedical subjects

R Shiba

Publications and source records attributed to R Shiba.

At least 55 records · Page 3Linked to original sources
PubMed1989

Mandible and tongue-splitting approach for giant cell tumor of axis.

In two cases with a giant cell tumor of the axis, the mandible and tongue-splitting approach permitted excision of the tumor and anterior fusion of the spine from the atlas to the third cervical vertebra. With this approach, there is no need to extend or rotate the cervical spine during the operation. In addition, the operative field extends from the clivus to the fourth cervical vertebra, and safe and sufficient anterior decompression is possible. Although this approach has some disadvantages, contemporary techniques of intravenous hyperalimentation and postoperative respiratory management provide a solution to these problems. Thus, this approach should always be considered for patients requiring extensive anterior decompression of the craniovertebral junction or upper cervical spine.

Adolescent↗
PubMed1988

Geometry of the humeroulnar joint.

Clinical results with elbow prostheses have been disappointing. A detailed knowledge of elbow joint geometry and mechanics is necessary to improve prosthetic design. In this study, the humeroulnar articulation of four human cadaver elbows was examined using surface analytic methods. In this article, the location of the transverse axis of elbow flexion-extension is suggested in relation to well-defined landmarks, the medial and lateral epicondyles, and subsequently to the line connecting their most lateral points--the transepicondylar line. The geometry of the structures responsible for the carrying angle is discussed, as is the extent of cartilage-covered bearing areas of the lower humerus and upper ulna. Implications pertaining to prosthetic design and surgical technique resulting from this study are discussed.

Cartilage, Articular↗
PubMed1987

[An experimental study of bone remodeling influenced by mechanical stress].

Bone remodeling influenced by mechanical stresses was studied using ambulatory chickens. They were divided into four groups with the different mechanical forces applied to the leg. I: running along a circular track, II: walking or standing on one leg, III: control, IV: casting. The animals were sacrificed after 12 weeks and undecalcified cross-sections of femurs and tibias were examined using a tetracycline labeling method. Bone formation was evident at both metaphyses of the femur and at the proximal metaphysis of the tibia. More bone formation was observed at the medial quarter of both femur and tibia than in comparison with the lateral quarter. There was, however, no difference in the membraneous ossification between the medial and lateral quarters in Group II. The lack of significant cortical drift at the medial side of the femur and tibia suggests that no bending moment is generated by standing on one leg.

Animals↗
PubMed1986

The development of a surface arthroplasty for the elbow.

Complex kinematics, anatomical features, and load distribution have contributed to the poor function of constrained and semiconstrained cemented arthroplasties of the elbow. Resurfacing by porous-coated components has the potential, by reproduction of normal joint geometry and restoration of ligament balance, to re-create relatively normal kinematics and load-bearing and provide relief of pain. A method was developed to provide information on the geometry of the lower humeral joint surface and olecranon fossa. The information gained was used to design components to resurface the trochlea, capitellum, and olecranon fossa. A technique was also developed to remove a minimal amount of subchondral bone from the ulna and humerus in a precisely directed fashion for exact fit of the porous-coated components.

Elbow Joint↗
PubMed1985

Diseases of the hip. A comparative study of Japanese Oriental and American white patients.

Pelvic radiographs of 200 consecutive Japanese Oriental patients who were admitted for hip surgery at the Hospital of Kobe University in Japan were compared with those of 199 consecutive American white patients who were admitted for the same purpose to a New England hospital over a similar four and a half-year period between 1972 and 1976. One hundred and fifty-three Japanese Oriental and 157 American white patients had either primary or secondary osteoarthritis. The remainder had other types of hip pathology, such as avascular necrosis, rheumatoid arthritis, and ankylosing spondylitis. The radiographs of five Japanese Oriental and seven American white patients showed evidence of previous Legg-Calvé-Perthes disease, coxa vara, or slipped capital femoral epiphysis. With only two exceptions, the osteoarthritis in the remainder of the Japanese Oriental patients was secondary, caused by antecedent congenital hip disease: twenty-eight had one or two congenitally dislocated hips, ninety-two had acetabular dysplasia, and twenty-six had superolateral osteoarthritis. In contrast, only nine of the American white patients clearly had a diagnosis of acetabular dysplasia, and twenty-six had superolateral osteoarthritis. Twenty-one American white men had a femoral head-tilt deformity. Among the Americans, the largest group (sixty-five patients) had superomedial osteoarthritis. Nine had non-rheumatoid protrusio acetabuli and twenty had axillary or concentric osteoarthritic involvement. The majority of American white patients, therefore, had a type of osteoarthritis that was not seen in the Japanese Oriental patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Traumatic myositis ossificans in the masseter muscle.

Traumatic myositis ossificans in the left masseter muscle of a 25-year-old man is described. The lesion, which extended intramuscularly from the lateral surface of the zygomatic bone to the mandibular angle, was resected by an intraoral approach. The specimen was composed of mature cortical bone in the outer portion and spongy bone, including degenerated muscle fibers and marrow spaces, in the inner portion. At the lower end of the specimen was a sequence of bone formation involving fibrous connective tissue, cartilage, woven bone, and mature lamellar bone with many osteoblasts. Clinicopathologic features of 26 reported cases of traumatic myositis ossificans of the maxillofacial region are reviewed, and the pathogenesis of the disease is discussed.

Adult↗
PubMed1984

[The relationship between electrical callus formation and the amount of electricity].

Electrical stimulation to enhance callus formation has been in use for some time now. This experiment was undertaken to find the relationship between electrical callus formation and the amount of electricity. In this experiment, the long bones of canines were stimulated by direct current and observed microscopically for callus formation. Moreover, distribution patterns of electric potential and current density were calculated theoretically by finite element method. The results are summarized as follows: Electrical callus formation was observed in the medullary canal with 8.7-20 microA direct current. Electrical callus is fibrous ossification and the peak of callus formation is from fourteen to twenty one days. There is no difference in volume and/or speed of callus formation between the simple and the constant direct current. Using platinum electrodes, the amount of callus formed around the cathode and anode is the same. To prevent electrolysis of the tissues, distance between electrodes must be kept at a minimum. On the other hand, the surface area of the electrodes must be widen to keep the electric potential at the minimum level. The area of callus formation is related to 5-10 microA/cm2 of electric current density.

Animals↗
PubMed1984

[Fatigue performance of Hoffmann-Vidal external fixator].

The question concerning reusability of the Hoffmann-Vidal frame has been widely discussed, but no definite recommendation can be made on scientific data. The present study was designed to investigate the change of frame stiffness and fatigue life of the components in a Hoffmann-Vidal quadrilateral fixator. Failures were found at the base of the pin fixation bracket rod. They can be classified into 3 types: complete rod fracture, incomplete rod fracture and loosening of the rod. Only complete fractures of the rod caused a significant reduction of frame stiffness. Strength and loosening torque were proportional to the initial tightening torque for both the universal ball joint and articulation coupling. The mean reduction of screw fixation strength was 16% after 2.5 million cycles. As a result of repeated tightening, two retaining screws from three universal ball joints were severely deformed and the threads flattened. Two fixation screws on the pin bracket and two square-headed screws on the adjustable connecting rods fractured at the 5th to 6th tightening sequence. Significant wear debris were observed during repeated tightening of the articulation coupling. No gross material defects were observed on the fracture surfaces of the failed components. The Hoffmann-Vidal external fixation apparatus may be safely used for four to five sequential applications provided that all critical components be carefully inspected and the fixation screws replaced after each application. The screws should be tightened appropriately using only the T-wrench in order to prevent overloading. These screws should be retightened periodically to maintain incorporated to minimize the screw and rod fractures and to avoid the wear problem after repeated tightening of the screws.

Biomechanical Phenomena↗
PubMed1983

Peripheral ameloblastoma.

Peripheral ameloblastoma is a rare odontogenic neoplasm, which arises in the tooth-bearing gingiva or other oral soft tissues and has no invasive character as compared with an intraosseous ameloblastoma. A new case of the neoplasm has been presented, and the literature concerning behavior, histogenesis, and treatment of this entity has been evaluated.

Adult↗
PubMed1983

The oral manifestations of 4p- syndrome.

The oral manifestations of 80 reported cases of 4p- syndrome are analyzed and a new case is reported. Results indicate that the common pattern of cheilognathopharyngeal disorders in 4p- syndrome is an isolated cleft palate or a high-arched palate with micrognathia. Cases of cleft lip are only about 10% of the total. The significance of other reported aberrant phenomena cannot yet be estimated.

Abnormalities, Multiple↗
PubMed1983

Lymphoepithelial cyst of oral cavity. Report of a case and review of the literature.

A rare case of the oral lymphoepithelial cyst in the ventral surface of the tongue is reported. Histological findings show the same appearance as reported previously, and the continuity of the cyst wall to the oral mucosa in the specimen is suspected. Some aspects of the lesion are reviewed, and its pathogenesis, as reported in the literature, is discussed.

Adult↗
PubMed1982

Histologic and histochemical investigation of Gaucher cells.

Electron microscopic investigations suggest that morphologically, Gaucher cells and histiocytes are very similar. The fact that there are tubular elements in the lysosomes strongly suggests the possibility of lysosomes as the precursors of Gaucher bodies. By means of the lectin staining methods, the localization of glucocerebroside is clearly demonstrable in Gaucher cells. Lectin staining is the significant diagnostic feature of both Gaucher's and Krabbe's diseases.

Biopsy↗
PubMed1981

Cementifying fibroma of the maxilla. Report of a case.

A case of cementifying fibroma growing into the right maxillary sinus is reported. Clinical and histopathological findings are presented. The differentiation from central fibro-osseous lesions in jaw bones is discussed.

Humans↗
PubMed1981

[A study on the stress analysis of the pelvis by means of the three-dimensional photoelastic experiments (author's transl)].

The processes are as follows: 1) Life-sized photoelastic models molded from a cadaver pelvis are made of Epoxy resin. 2) In order to practice the stress freezing process, the models are set to our original loading apparatus in the electric heater. The forces exerted on the hip models are both body weight and four kinds of muscular forces, those of the abductor, adductor, rectus femoris and gluteus maximus. 3) After the stresses are frozen in the models, they are cut off into slices to observe isochromatic and isoclinic lines. 4) In the stress analysis both the shear difference method and the double slice method are utilized to obtain more accurate stress distributions. And the results have been summarized as follows: 1) In the ring-shaped slices large stresses are observed especially at four areas; namely the central area of the iliac bone, the acetabulum proximal to the ilium, the pubic ramus and the area adjacent to the sacroiliac joint. The specific areas where hydrostatic pressure works are seen at two points in the deep acetabular cavity. 2) The principal stress lines of almost all slices tend to flow smoothly and monotonously along the ilium, the sacrum and the pubic bone, but as they approach the acetabulum they run in complex patterns and make some singular points. 3) Around the acetabulum the principal stress lines of one group run in concentric circles and those of the other group radiate in all directions from the center of the acetabulum at the upper half of the dome which supports the load. The stress here was 5 to 6 times greater than in the lower half of the dome. 4) The acetabulum is stretched vertically and deformed into an oval shape. The horse shoe-shaped articular facet is deformed as both beaks approach each other. 5) As for the slices of the pelvic ring the normal acetabulum tends to be obviously deformed as it holds or embraces the femoral head. As a result of this deformity the stability between the acetabulum and the head increases. On the other hand the dysplastic acetabulum shows none of those phenomena. 6) The iliac bone of the pelvic ring is deformed into the "S" shape and the pubic ramus the "C" shape, the "S" shape, or the "Z" shape depending on the limb position. The pelvic ring tends to be deformed into a heart shape during abduction.

Acetabulum↗
PubMed1979

[The effect of calcitonin on contractile function of skeletal muscles (author's transl)].

The analgesic effect of calcitonin in osteoporosis has been considered to originate from its actions on bone metabolism. However, the author assumed a possible presence of other mechanism, since the analgesic effect of calcitonin manifests in an extremely early phase in which an increase in bone mass is hardly conceivable. Namely, the author postulated that its analgesic effect is due to its actions on body trunk muscles, and investigated experimentally the effect of calcitonin on skeletal muscles. The following results were obtained. 1) Recovery from decreased twitch contraction of M. triceps surae was shown in vivo in rats treated with calcitonin, with dose-response relationship. 2) Calcitonin exerted no effect on partial blockade by dTc, in neuro-muscular junction. Therefore, the neuro-muscular junction is probably not the site of the actions of calcitonin. 3. In an in vitro study on isolated M. soleus, the decrease contraction was recovered after treatment with calcitonin. A correlation was found between this recovery and the dose of calcitonin. 4) In the calcitonin treated muscle, a pronounced persistence of normal contraction was demonstrated in contrast to the control group. 5) Calcitonin appears to facilitate Ca release through exerting actions on Ca transport system in the sarcoplasmic reticulum. From these results, it was shown that calcitonin appears to possess an activity to elevate contractile ability of skeletal muscles. This activity is considered to be derived from its effect on sarcoplasmic reticulum. This activity of calcitonin on contractile function of skeletal muscles indicates the presence of a mechanism relating to skeletal muscles in the analgesic effect on low back pain in osteoporosis.

Animals↗