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Biomedical subjects

T Ohira

Publications and source records attributed to T Ohira.

At least 127 records · Page 7Linked to original sources
PubMed1989

Ultrastructural study of articular cartilage in experimental pyogenic arthritis.

Ultrastructural changes of the articular cartilage at the early stage of experimental pyogenic arthritis were studied by electron microscopy. The superficial zone of the cartilage at the site of the cartilage-synovium junction demonstrated far more changes than those at the site of the free surface of the articular cartilage. Changes were observed at the cartilage-synovium junction as early as four hours after the intraarticular injection of the infecting organism. The most interesting finding was migration of erythrocytes and polymorphonuclear leucocytes into the superficial zone of the cartilage at the early stage. The pericellular matrix in the middle zone became so loose in some areas that collagen fibrils were partially exposed after three days. The naked collagen fibrils were tapered, nicked and irregular in size after seven days.

Animals↗
PubMed1988

Histologic localization of lipid in the articular tissues in calcium pyrophosphate dihydrate crystal deposition disease.

We demonstrated the histologic localization of lipid in the articular cartilage, meniscus, and synovium in calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, by staining with Sudan III. Almost all the sites of tophus-like deposits of CPPD crystals and the degenerated matrix containing low concentrations of scattered CPPD crystals stained strongly with Sudan III. Transmission electron microscopy demonstrated round or oval lipid droplets in more than half of the chondrocytes around the crystals in each of these tissues. Small lipid droplets were also seen on or around the crystals. These findings suggest that lipids are abundant at the site of CPPD crystal deposition and may be involved in CPPD crystal formation.

Aged↗
PubMed1988

Persistent hemarthrosis of the shoulder joint with a rotator-cuff tear in the elderly.

Three elderly patients developed persistent hemarthrosis of the shoulder joint without having suffered injury. Complete tears of the rotator cuff, attrition of the undersurface of the acromion, and instability were noted in the affected shoulders. Synovial fluids examined from two patients contained many alizarin red S-positive microspheroids. The synovium obtained at surgery from two patients showed hypervascularity, vasodilatation, and severe degenerative changes of collagenous tissues. The tendon of the m. supraspinatus showed infiltrations of multinucleated giant cells around calcified deposits consisting of hydroxyapatite crystals. Anatomical and mechanical derangements, and possible biological reactions following phagocytosis of hydroxyapatite crystals, may have contributed to the persistent hemorrhage in the shoulder joints.

Acromion↗
PubMed1988

A modified extended middle cranial fossa approach for acoustic nerve tumors. Results of 125 operations.

During the past 10 years, 125 operations for acoustic nerve tumors were performed on 114 patients at the authors' institution using a modified extended middle cranial fossa approach. This approach is based on a combination of King and Morrison's translabyrinthine-transtentorial approach and on the extended approach through the middle cranial fossa described by Bochenek and Kukwa. There were two hospital deaths (operative mortality 1.6%). In 102 operations on the initial tumor, total removal was performed in 89 cases (87%), and in 71 (80%) of these the facial nerve was anatomically preserved. Intracranial end-to-end anastomosis was performed on five of the 18 sacrificed facial nerves; a facial-hypoglossal anastomosis was carried out in the remaining 13 patients and in five (7%) of the 71 patients whose anatomically preserved facial nerve functioned poorly. In seven (39%) of the 18 patients in whom an attempt to preserve hearing was made, postoperative hearing was saved. In 23 operations on 17 patients for recurrent tumors, most of which had previously been removed subtotally via the suboccipital approach, total removal was accomplished in 13 (57% of the 23 reoperations and 76% of the 17 patients). At reoperation, the facial nerve was preserved in six (55%) of the 11 patients in whom the facial nerve had not been sacrificed. Postoperative leakage of cerebrospinal fluid occurred in 11 cases (8.8%), with rhinorrhea in 10 cases and otorrhea in one. Five of the fistulas were corrected by surgery and the rest healed spontaneously. Other complications were not significant.

Adolescent↗
PubMed1988

[Intraoperative electrophysiological monitoring for hearing preservation in acoustic neurinoma surgery].

Five acoustic neurinomas have been operated with hearing preservation as a goal. We monitored intraoperative brainstem auditory evoked potentials (BAEP) in all five cases, electrocochleogram (ECoG) using needle electrode in external auditory meatus in four, and compound action potentials directly recorded from the cochlear nerve (CAP VIII) in three. In all five cases the tumor was totally resected and cochlear nerve was anatomically preserved. However, in only one case useful hearing was preserved with preservation of all wave forms of the BAEP. Another patient with preservation of all wave forms of BAEP and the ECoG showed postoperative severe hearing loss. Other three patients showed postoperative severe hearing loss: only Wave I of BAEP and ECoG were preserved without preservation of the CAP VIII in one whose cochlear nerve was thought to be damaged in cerebellopontine angle cistern; Wave I of BAEP, ECoG and CAP VIII were preserved in one in whom it was suggested cochlear nerve near brainstem or cochlear nucleus was damaged; none of the BAEP, ECoG and CAP VIII was preserved in one in whom it was suggested distal cochlear nerve, or internal auditory artery was damaged. These different patterns of changes suggested that different causes for the hearing loss and difficulties in hearing preservation during acoustic neurinoma surgery. Having identified the putative mechanism of the hearing loss by monitoring those potentials, suggestions are made about how such hearing loss might be avoided. For preservation of the hearing in acoustic neurinoma surgery, all of those potentials including all wave forms of BAEP, ECoG and CAP VIII should be preserved during surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1988

[Clinicophysiological study of multimodality evoked potentials and computed tomographic findings in persistent vegetative state].

The auditory brainstem response (ABR), short latency somatosensory evoked potential (SSEP) and visual evoked potential (VEP) of patients in the persistent vegetative state (PVS) are reported, and the correlations between the electrophysiological findings and the CT scan findings with the three clinical grades of the PVS (transitional, incomplete and complete vegetative syndromes) are discussed. Twenty two patients in a vegetative state caused by subarachnoid hemorrhage (3), hypertensive intracerebral hemorrhage (5), cerebral infarction (6), head injury (3), cerebral anoxia (4) and brain tumor (1). Each evoked response was evaluated for the presence or absence of abnormalities and assigned a grade ranked I to III. Briefly an evoked response was assigned a grade I, II, III if it satisfied the respective criteria of normal, moderately abnormal and severely abnormal or absent electrical activity. On the other hand CT scan findings in the PVS were evaluated for abnormal low density areas, ventricular dilatation and enlargement of the sulci and cisterns indicative of atrophy of the brain parenchyma. SSEP and VEP were better correlated with the clinical grade than ABR, and upper brainstem atrophy and abnormal low density area in CT scan findings were more valuable as an index to expresses the clinical features than ventricular dilatation. On the basis of these results, it is concluded that studies of ABR, SSEP and VEP associated with CT scan findings in the PVS could be a useful diagnostic aid to evaluate the lesions of these patients.

Adult↗
PubMed1987

Hydroxyapatite deposition in osteoarthritic articular cartilage of the proximal femoral head.

Hydroxyapatite crystal deposition in the articular cartilage of the proximal femoral head was examined by using light and electron microscopy and electron probe microanalysis. The hydroxyapatite deposition was significantly more frequent in patients with osteoarthritis (40.7%, 22 of 54) than in control subjects (6.0%, 3 of 50) (P less than 0.001). Initial deposition of needle-like crystals was always seen on or within the electron-dense, amorphous material around the degenerating hypertrophic chondrocytes. Matrix vesicles were rarely seen in the calcifying areas.

Cartilage, Articular↗
PubMed1987

[Monitoring of antidromic facial nerve action potentials in cerebello-pontine angle tumor operations].

A method of recording the antidromic facial nerve compound potential (AFNAP) is presented. When the facial nerve is stimulated, a compound action potential is propagated in both directions from the stimulating site. We recorded AFNAP's in 6 cases of cerebello-pontine angle (CP angle) tumors (5 acoustic neuromas and one epidermoid) using a bipolar silver ball-type electrode directly put on the facial nerve in CP angle by stimulation of the peripheral facial nerve at the stylomastoid foramen. It was necessary to use needle electrodes instead of surface ones for stimulation to keep the artefacts from stimulating currents within reasonable bounds. Good contact of the electrode tips with facial nerve was required to get clear action potential. By stimulation with needle electrodes AFNAP's were recorded without averaging and had a good reproducibility. AFNAP's were typical triphasic potentials and the major negative peak latencies were observed from 1.5 to 3.4 msec except one case of recurrent epidermoid whose major negative peak latency was 7.6 msec. It was verified that these potentials were the results of facial activity, because they were recorded exclusively on the facial nerve, they could not be recorded at the proximal end of the sectioned facial nerve, and alterations of latency were observed with changing the position of recording electrode along the facial nerve. A calculated conduction velocity was about 50 m/sec. It was thought that recording AFNAP facilitated the identification of the facial nerve on the surface of the CP angle tumor, because the amplitude of AFNAP decreased immediately when the recording electrodes were off from the facial nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1986

Echocardiographic detection and treatment of intraoperative air embolism.

A real-time two-dimensional echocardiogram was used to detect the presence of an air embolism in patients undergoing neurosurgical procedures in the sitting position. The technique could with good sensitivity detect the appearance of a single air bubble intraoperatively, thus allowing early intervention to prevent development of further air emboli. Two types of air embolism could be differentiated; the single-bubble type and the "stormy-bubble" type. The single-bubble type was observed during skin and muscle incisions, craniotomy, and brain lesion excision. Further embolism development was prevented by electrocoagulation and application of bone wax. The stormy-bubble type occurred during dura and muscle incisions and was prevented by electrocoagulation, reflection of the dura, or suturing the affected muscle. The routine use of a Swan-Ganz catheter for removal of air embolism by suction proved effective for the treatment of the stormy-bubble type of air embolism. Masking the operative field with saline-soaked cotton strips was of moderate benefit in the stabilization of the single-bubble type of air influx, but proved to be of little value in controlling the entrance of the stormy-bubble type.

Echocardiography↗
PubMed1986

Hydroxyapatite deposition in articular cartilage by intra-articular injections of methylprednisolone. A histological, ultrastructural, and x-ray-microprobe analysis in rabbits.

The mineral deposits in rabbit articular cartilage induced by intra-articular injections of glucocorticoid were studied by light and electron microscopy, using histochemical techniques and x-ray-probe microanalysis. This study demonstrated that the mineral deposits consisted of hydroxyapatite crystals. The initial deposition of hydroxyapatite crystals was seen around degenerating chondrocytes, where a halo-like pericellular space contained a large amount of electron-dense amorphous material. The initial precipitation of the crystals with a low ratio of calcium to phosphorus and the subsequent growth of crystals were seen only on or within the electron-dense amorphous material until the crystals formed mature, calcified nodules. The electron-dense amorphous material frequently coexisted with proteoglycans and degenerated collagen fibers. Digestion studies using chondroitinase ABC, papain, or chloroform and methanol suggested that the electron-dense amorphous material consisted of some protein and a small amount of lipid. Matrix vesicles were rarely seen in the calcifying areas. In addition, there was a correlation between sulphur, calcium, and phosphorus in the calcifying areas, where the relative element concentrations were: S (estimation counts of sulphur) = -0.862 X (calcium counts) + 1.472 X (phosphorus counts) + 102.146. This study demonstrated that electron-dense amorphous material, proteoglycans, and degenerated collagen fibers are present in loci where the hydroxyapatite crystals are formed in articular cartilage.

Animals↗
PubMed1985

Experimental study on postlaminectomy deterioration of cervical spondylotic myelopathy. Influences of intradural surgery and persistent spinal block.

This experiment studied the postoperative changes around the dural tube at the site of cervical laminectomy, which are influenced by intradural operative procedures and the flow of cerebrospinal fluid. Forty dogs were divided into four groups in accordance with the type of decompressive procedure done, and three types of dural surgery were added: none (laminectomy alone), dura resection, or arachnoid resection. While the scar tissue did not adhere to the spinal cord after arachnoid resection in normal dogs, adhesion of scar to spinal cord was seen to a small extent after arachnoid resection with sufficient posterior decompression in dogs whose spinal cord was compressed anteriorly by a screw through the vertebral body. In the cases with insufficient posterior decompression adherence was observed much more extensively.

Animals↗