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Biomedical subjects

I Aoyama

Publications and source records attributed to I Aoyama.

At least 37 records · Page 2Linked to original sources
PubMed1997

Stimulation of bone formation by intraosseous application of recombinant basic fibroblast growth factor in normal and ovariectomized rabbits.

The effect on intraosseous bone formation of a single local injection of recombinant human basic fibroblast growth factor into the distal femur was examined in normal and ovariectomized rabbits. In normal rabbits, basic fibroblast growth factor increased bone mineral density around the injected site in a dose-dependent manner at 4 weeks, with significant effects at concentrations of 400 micrograms and greater. Doses of 400 and 1,600 micrograms of basic fibroblast growth factor increased bone mineral density by 8 and 9%, respectively, compared with the opposite control femur. Histological examination showed that basic fibroblast growth factor (400 micrograms) induced the proliferation or recruitment of undifferentiated mesenchymal cells around the existing trabeculae at 3 days after the injection. For the first 2 weeks, osteoid formation was strongly stimulated, and this was followed by mineral apposition for another 2 weeks, at which time the femurs were harvested. Consequently, basic fibroblast growth factor stimulated intraosseous bone formation at 4 weeks. We speculate that the direct action of basic fibroblast growth factor on bone formation may be to stimulate proliferation or recruitment of minimally differentiated mesenchymal cells and to initiate the cascade of events in later stages of bone formation. In ovariectomized rabbits, basic fibroblast growth factor (400 micrograms) also increased bone mineral density, histomorphometrical bone formation markers, and trabecular connectivity to levels similar to those in rabbits who had received sham operations.

Animals↗
PubMed1997

Stimulation of endosteal bone formation by local intraosseous application of basic fibroblast growth factor in rats.

We investigated the effects of local intraosseous application of basic fibroblast growth factor under physiologic conditions. An aqueous solution containing 0 (vehicle), 25, 100, or 400 micrograms of basic fibroblast growth factor was injected via a needle into the ilium of rats. Two weeks later, bone mineral density of the ilium was significantly increased (P < 0.01) with all three doses, and a dose-effect relationship was apparent. Light microscopy revealed proliferation of undifferentiated mesenchymal cells on the endosteal and trabecular surfaces, as well as apposition of newly formed bone on existing trabeculae. Intraosseous injection of basic fibroblast growth factor may be of use for the treatment of osteoporosis.

Administration, Topical↗
PubMed1996

Local application of basic fibroblast growth factor into the bone increases bone mass at the applied site in rabbits.

The effect of basic fibroblast growth factor (bFGF) applied locally into the bone under physiological conditions was investigated. An aqueous solution containing 0 microgram (vehicle), 100 micrograms or 400 micrograms recombinant human bFGF was percutaneously applied through a needle into the right ilium in rabbit, and the ilia were harvested 4 weeks after the application. Compared with vehicle-treated animals, bone mineral density measured by dualenergy X-ray increased in the 400 micrograms bFGF group. The width of trabeculae in the bFGF-treated groups was greater than in the vehicle group. These results showed that bFGF applied locally into the bone under physiological conditions affected bone formation, and suggested that such an application might have potential for increasing bone.

Absorptiometry, Photon↗
PubMed1994

Histological studies on the rheumatoid synovial membrane irradiated with a low energy laser.

The beneficial effects of low energy laser irradiation on rheumatoid arthritis (RA) joints have been reported, but the mechanisms of action of low energy lasers in RA are unclear. The synovial membrane in cases of RA was studied histologically to observe the effects of low energy laser irradiation. Fourteen knee joints of RA cases, which had been scheduled for arthroplasty, were irradiated with a gallium-aluminium-arsenide (Ga-Al-As) laser (790 nm in wavelength and 10 mW of output power) prior to the surgical operation, at six points of the external aspect of the knee joint for 80 seconds at each points once a day for 6 days. On the day following the last irradiation, pieces of synovial membrane from the lateral irradiated area and from the median nonirradiated area as a control were resected during the arthroplasty. The histological findings of the irradiated synovial membrane showed flattening of epithelial cells, decreased villous proliferation, narrowed vascular lumen, and less infiltration of inflammatory cells compared with those of nonirradiated synovia. The evaluation of slides was done in a blinded manner, and significant differences was seen by Wilcoxon's t-test (P < 0.01). Histological findings suggested that the low energy laser irradiation induced suppression of inflammation in the synovial membrane of RA.

Arthritis, Rheumatoid↗
PubMed1994

Germinoma in siblings: case reports.

We present the first reported cases of germinoma occurring in siblings of different genders. One tumor occurred in the left basal ganglia of a 7-year-old boy and the other in the suprasellar region of his 9-year-old sister. Both tumors were diagnosed as germinoma of two-cell pattern based on light and electron microscopic studies. Possible genetic factors responsible for this phenomenon are discussed.

Adolescent↗
PubMed1991

Pneumocephalus associated with benign brain tumor: report of two cases.

Two cases of spontaneous pneumocephalus, which developed after ventriculoperitoneal shunt procedures for severe hydrocephalus caused by benign brain tumors, are reported. In both cases there was no previous history of cerebrospinal fluid leakage. Operation revealed that both patients had many small defects of the dura mater and the bone in the middle cranial fossa, which were plugged by necrotic brain tissue. These defects were remote from the sites of the original tumors but may have been produced by long-standing raised intracranial pressure, and they presumably allowed air to enter after intracranial pressure was reduced by shunting. Repair of the defects prevented further intracranial air retention.

Adult↗
PubMed1991

Effects of fluorine emission on agricultural products surrounding an aluminum factory.

The F concentrations of precipitate dust, agricultural products, and fingernail and hair at the surrounding Al factory were investigated. The F content of dust ranged from 15400 to 42500 micrograms/g dry weight, 190,000 to 380,000 micrograms/g Al. Rice grain contained about 3.4 times more F than that in the control area, but some kinds of agricultural products, egg plants (S. melongena L.), mulberry plants (M. japonica Bailey non Sieb.), and soy beans (G. max (L.) Merrill) were almost equal to that of controls. Also, the high F concentration in the hair and nails of some workers was affected by available F contents in the emission from the factory as well as food and water surrounding the aluminum factory compared with those of control area.

Air Pollutants↗
PubMed1991

Role of hydrosulfide ions (HS-) in methylmercury resistance in Saccharomyces cerevisiae.

Methylmercury-resistant mutants were obtained from Saccharomyces cerevisiae. They were divided into two complementation groups, met2 (homoserine O-acetyltransferase deficiency) and met15 (enzyme deficiency unknown), as reported previously. It was found that met15 was allelic to met17 (O-acetylserine and O-acetylhomoserine sulfhydrylase deficiency). Methylmercury toxicity was counteracted by exogenously added HS-, and both met2 and met17 (met15) mutants overproduced H2S. On the basis of these results, we conclude that met2 and met17 (met15) cause accumulation of hydrosulfide ions in the cell and that the increased level of hydrosulfide is responsible for detoxification of methylmercury.

Drug Resistance, Microbial↗
PubMed1991

Trigeminal neuralgia caused by compression from arteries transfixing the nerve. Report of three cases.

The authors present three patients with trigeminal neuralgia due to compression by an artery that transfixed the sensory root of the fifth cranial nerve. These cases represented 0.8% of 384 patients with trigeminal neuralgia treated by microvascular decompression at the authors' clinic during the past 12 years. In the remaining 381 cases, the compressing vessels were successfully removed from the trigeminal nerve without much difficulty, for an initial cure rate of 94.3%. In the three cases reported, however, the compressing artery penetrating the nerve could not easily be maneuvered away from the nerve. In the first two cases, partial rhizotomy perpendicular to the axis of the nerve at the site of arterial transfixion made it possible to separate the artery from the nerve. However, these two patients developed postoperative facial sensory impairment. In the third case, rhizotomy was performed longitudinal to the axis of the nerve at the site of arterial transfixion, making it possible to reposition the artery peripherally beyond the root entry zone of the nerve without causing any postoperative sensory deficits of the face. No recurrent pain has developed in more than 2 1/2 years since surgery in any of these three cases. When performing microvascular decompression surgery on patients in whom the compressing artery penetrates the nerve, the technique used in our third patient is the procedure of choice.

Aged↗
PubMed1991

[Anterior decompression surgery of aged patients with cervical myelopathy].

One hundred and thirty-nine patients with cervical myelopathy who underwent anterior decompression surgery were reviewed to determine the characteristics and surgical outcome in 26 elderly patients over the age of 65. The mean age of the aged group was 69.7 and that of the remaining 113 patients was 50.0. Extensive spur removal and interbody fusion with iliac bone graft were performed in all patients. Evaluation of clinical grades was based on the Japan Orthopedic Association Score (JOA score) on admission, at discharge and at the time of follow-up (mean 26.8 months). The improvement rate was calculated from Hirabayashi's formula at each point. Preoperatively, the mean duration of illness was longer and the mean JOA score was significantly lower in the aged group. Furthermore, low incidence of soft disc and multi-level lesions were characteristic for the aged. Final JOA score increased from 8.2 to 13.0 in the aged group, while that in the non-aged group increased from 10.5 to 14.8. These differences were statistically significant at each point. Excellent and good results which were designated as an improvement rate of 50% or more were obtained in 73.1% of the aged group, and in 79.6% of the non-aged group. Postoperative complications were slightly more frequent in the aged group, all of which, however, were dislocation of bone graft seen in 3 patients. As compared with the non-aged group, poorer surgical outcome in the aged group was attributed to preoperative poor clinical condition, long duration of preoperative symptoms, low incidence of soft disc herniation and multi-level lesions which were characteristic features for the aged patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

The critical levels and the maximum metal uptake for wheat and rice plants when applying metal oxides to soil.

Wheat is more sensitive to CdO and ZnO compared with rice plant. The yield of wheat decreased by 30% in the presence of 30 ppm Cd, but that of rice plants by only 8%. The critical levels of meal uptake by wheat and rice plants for applying metal oxides to soil (CdO, ZnO, PbO) were determined. The highest concentration obtained for wheat grain was 141 micrograms/g Cd at the Cd 10,000 ppm in soil. This value is higher than the value of 4.97 micrograms/g for unpolished rice and higher than any other we have seen in the reports for treatment with CdO. Also, concentration of more than 1.0 micrograms/g Cd in wheat was observed at 5 pm Cd, while similar concentrations for rice plants were observed at 30 ppm Cd in soil.

Cadmium↗
PubMed1990

Calcified metastatic brain tumor.

The case of a 57-year-old woman with a calcified metastatic brain tumor, histologically confirmed to be a squamous cell carcinoma, is reported. This patient is unusual because this metastatic squamous cell carcinoma contained an extraordinary huge conglomerated calcification, that was well-defined radiographically. This case is documented with a discussion of the pathogenesis of the calcification.

Brain Neoplasms↗
PubMed1990

Subarachnoid hemorrhage possibly caused by a saccular carotid artery aneurysm within the cavernous sinus. Case report.

Aneurysms arising from the intracavernous portion of the internal carotid artery very rarely rupture. A patient is presented in whom rupture of an aneurysm wholly within the cavernous sinus caused a subarachnoid hemorrhage. The aneurysm was successfully clipped via a direct surgical approach. The possible mechanism by which subarachnoid hemorrhage occurred is briefly discussed.

Aneurysm↗
PubMed1989

Primary interosseous meningioma associated with pregnancy--case report.

The authors present the case of a 32-year-old female with a hard, bony mass on her left forehead, present for several years, which rapidly increased in size after she became pregnant. Neuroradiologically, the tumor appeared to have originated in the interosseous space, and it invaded the subgaleal and intracranial spaces as the pregnancy advanced. The tumor was explored and removed after delivery. Light and electron microscopic studies verified that it had the characteristics of a typical meningotheliomatous meningioma. Interosseous meningiomas are biologically and morphologically similar to intracranial meningiomas and must be followed carefully during pregnancy because of their potential for rapid growth at this time.

Adult↗
PubMed1988

Calcification of a ventriculoperitoneal shunt tube. Case report.

A 16-year-old boy who had undergone a ventriculoperitoneal (VP) shunt because of hydrocephalus at 8 years of age complained of pain around the right neck and chest. He concomitantly had a slight fever of unknown etiology, which had been lasting for several years. Skull and chest roentgenograms revealed an unusual calcified shadow around the shunt tube. After removal of the shunt apparatus, his pain and fever disappeared. Silicone tubes used in a VP shunt apparatus may induce fibrous connective tissue proliferation around the tubes in both children and adults, but no reports of radiologically verified calcification of a VP shunt tube are found in the literature, to the best of our knowledge. The possible mechanism of calcification of the VP shunt tube is discussed.

Adolescent↗
PubMed1988

[A case of spontaneous superficial temporal artery aneurysm].

A rare case of a 14-year-old boy with a spontaneous (true) aneurysm of the superficial temporal artery is presented. The mass in the right parietal region was pulsatile and gradually enlarged in size for the last several months without any notable history of head trauma. The mass was successfully removed by surgery and has proved histopathologically to be a true aneurysm. While almost all cases of the superficial temporal artery aneurysm reported are traumatic ones, the true aneurysm of this artery which is verified by angiography is extremely rare. The pathology, etiology and treatment of this true aneurysm of the superficial temporal artery were discussed.

Adolescent↗