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Biomedical subjects

Y Horikawa

Publications and source records attributed to Y Horikawa.

At least 145 records · Page 8Linked to original sources
PubMed1990

Effects of atrial natriuretic peptide on ischaemic brain oedema evaluated by the proton magnetic resonance method.

The effect of atrial natriuretic peptide (ANP) on cerebral oedema in rats was examined by magnetic resonance (MR). After occlusion of the left middle cerebral artery (MCA) to induce cerebral ischaemia, rats received continuous infusion of ANP for 24 h at a total dose of 120 micrograms/kg or 150 micrograms/kg. Proton relaxation times (T1 and T2) of excised oedematous tissue were measured in vitro and the area of the oedematous region was determined in vivo by the use of magnetic resonance imaging (MRI). The administration of ANP was found to decrease the lengthening of both T1 and T2 in the oedematous tissues and shown by MRI to decrease the area of the oedematous region, compared with group receiving saline. The topographic observations in vivo suggest that ANP suppress the development of the oedematous region.

Animals↗
PubMed1990

Lewy bodies in the lower sacral parasympathetic neurons of a patient with Parkinson's disease.

Lewy bodies were observed incidentally in the neurons of the dorsal group of nucleus intermediolateralis of the 3rd sacral segment of the spinal cord in a 74-year-old male with Parkinson's disease. The findings indicate the degeneration of the preganglionic parasympathetic neurons innervating the internal anal sphincter. The correlation between the findings and the mechanism of constipation in this disease are discussed.

Aged↗
PubMed1990

Demyelination and remyelination in spinal cord lesions of human lymphotropic virus type I-associated myelopathy.

We describe postmortem findings in a patient with human T lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). The patient developed the disease 8 years after blood transfusion and showed good response to corticosteroid treatment but died of cardiac failure. Histologically, chronic, mild meningoencephalomyelitis was noted predominantly involving the bilateral lateral and anterior columns of the middle to lower thoracic segments. The spinal cord lesions showed obvious loss of myelinated nerve fibers and fibrillary gliosis with minimal inflammatory cell infiltration. Electron microscopy of the lesion revealed disintegration of the myelin sheaths, regular separation of the minor dense line of the myelin sheaths, and completely demyelinated axons. In addition, remyelinated fibers with thin central myelin sheaths and disproportionately large axons were seen frequently. These findings indicate that primary demyelination and remyelination by oligodendrocytes occur in the spinal cord lesions of HAM.

Aged↗
PubMed1989

Evidence for sequential degeneration of the neurons in the intermediate zone of the spinal cord in amyotrophic lateral sclerosis: a topographic and quantitative investigation.

To elucidate the degenerating mechanism of the neurons in the intermediate zone of the spinal cord in classical amyotrophic lateral sclerosis (ALS), the spinal neurons in a patient with ALS, whose muscular strength was fairly well preserved up to death, were examined quantitatively and topographically, and compared with the data of advanced ALS patients and age-matched control subjects reported previously. In advanced ALS patients, anterior horn cells completely disappeared and the medium-sized (nuclear area; 71-150 microns 2) and large (nuclear area; greater than 151 microns 2) neurons in the intermediate zone were severely reduced. In the present case, however, the loss of anterior horn cells was severe but the degree was not equal to that of advanced ALS patients, and the neurons in the intermediate zone were quite well preserved. The finding indicates that the primary degeneration may occur in the anterior horn cells and the neurons in the intermediate zone degenerate sequentially in the spinal gray matter in ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1989

Magnetic resonance imaging of brain contusion.

In this study we investigated the time course of brain contusions using magnetic resonance imaging and compared the findings with those of a computed tomography scan. The lesions, which were demonstrated as homogeneous density areas on the computed tomography scan were demonstrated as different intensity areas in the magnetic resonance image. The intensity of the images varied according to the time at which the images were obtained. The findings indicated changes in the nature of the contusions including hematoma hemoglobin, perifocal edema extension, and so on. In conclusion, magnetic resonance imaging is important in the follow-up of chronological change as well as in original diagnosis of brain contusions.

Adolescent↗
PubMed1989

Nonacute subdural hematoma: fundamental interpretation of MR images based on biochemical and in vitro MR analysis.

Few reports have described the nature of the appearance of nonacute subdural hematoma on magnetic resonance (MR) images. The authors analyzed MR images in 39 cases of nonacute subdural hematoma and subdural effusion by measuring in vitro proton relaxation times and the biochemical variables of hematoma fluids. T1 became proportionally shorter than T2 with an increase in hematocrit but the direct cause of the variation in T1 and T2 was the amount of methemoglobin. The free iron content, not the bound iron content, was another main cause for shortened T1 and T2. Paradoxical findings in the correlation between the total protein or albumin concentration and relaxation times were noted. It is possible that as the protein level in the supernatant increased, more free iron was bound to the protein, decreasing the influence of the free iron on the relaxation times.

Adult↗
PubMed1988

The investigation of experimental brain tumours using 31P-MRS and 1H-MRI.

In vivo 31P-magnetic resonance spectra (MRS) were obtained by the surface coil method from rat glioma, human glioblastoma, and human neuroblastoma inoculated subcutaneously in CD Fisher rats and hamsters, and the effects of chemotherapy, photoradiation therapy, and radiofrequency hyperthermia as well as 60Co-irradiation were evaluated by sequentially observing spectral changes. In the 31P-spectra of tumour tissue, the nucleoside triphosphate (NTP), phosphomonoesters (PME) peaks were high and the phosphocreatine peak was low compared to those of normal brain. When the antitumour agents were given and were effective, NTP peaks decreased, and inorganic phosphate increased remarkably within several hours after the treatment. 1H-magnetic resonance imaging (MRI) were also obtained in some cases. Necrotic regions was detected by the 1H-MRI as image changes which appeared later than those detected by MRS. It proved practical to monitor the effect of therapy by employing either 31P-MRS or 1H-MRI. However, the image changes which demonstrated the effect of the therapy used closely resembled those changes which occurred with the onset of necrosis in tumour tissue during tumour growth. Several problems for future application of these techniques to human brain tumours are also mentioned.

Animals↗
PubMed1988

Pathophysiological investigation of experimental cerebral ischaemia using in vivo 31P-NMR spectroscopy and 1H-MRI.

The cerebral energy metabolism and brain oedema were investigated in three experimental cerebral ischaemia models using 31P-NMR spectroscopy (MRS) and 1H-NMR imaging (MRI) in the same subject animal. These measurements were performed also in experimental brain oedema models and the findings were compared with each other. 31P-MRS showed an ischaemic pattern in all of the cerebral ischaemia models, that is, ATP and PCr peaks decreased, and the Pi peak increased and shifted to a higher resonant frequency. However, 31P-MRS did not show any remarkable change in the brain oedema models. On the other hand, 1H-MRI clearly demonstrated brain oedema in the brain oedema model. In the cerebral ischaemia models, 1H-MRI findings differed depending upon the type of model, namely the most marked brain oedema was detected in the unilateral middle cerebral arterial occlusion model and no marked change was detected in the temporary four vessel occlusion model. It was thought that this difference depended on the severity of the ischaemic insult. Accordingly, the fundamental pathophysiological problem of cerebral ischaemia was the energy metabolism disturbance with the brain oedema being associated with this disturbance but occurring secondarily. However, in the brain oedema model the main pathological change was the increase in tissue water.

Animals↗
PubMed1988

[The usefulness of intracavitary brachytherapy in esophageal cancer].

Two different irradiation methods for the treatment of esophageal cancer have been compared and analyzed. One group of 146 patients were treated by external irradiation alone at the Aichi Cancer Center Hospital, while another group, consisting of 76 patients, were treated by external irradiation combined with booster intracavitary brachytherapy utilizing Radium-226 tubes at the National Sapporo Hospital. The patients that were treated by the addition of booster intracavitary brachytherapy showed a better response than the patients treated by external irradiation alone, with respect to the local control rate and survival. Booster intracavitary brachytherapy was found to be a more effective method for patients with esophageal smaller lesions and/or patients manifesting the serrated spiral, or funnel type lesions in their X-rays.

Brachytherapy↗
PubMed1987

Laser scanning microscope: differential phase images.

A beam-deflection type laser scanning microscope for differential phase contrast images using the split-detector technique is developed and the images are obtained in real time (30 images/s). The special optical design allows transfer of the pupil information necessary to the imaging of the differential phase contrast images during beam deflection and the use of acousto-optic deflectors with the associated correction system enables real time imaging. Differential phase images of surface details of crystals are simply obtained without silver coating or etching, which are indispensable in a normal DIC. Biological specimens are also observed.

Crystallization↗
PubMed1987

[The use of CT in the treatment of lung cancer with radiation therapy].

In this study, the extent to which CT accuracy in the diagnosis of regional lymph node metastasis of non-small cell lung cancer contributed to treatment results with radiation therapy was examined. The long-termed survival rate of 133 cases examined by CT scanning was superior to that of 154 cases diagnosed by conventional radiological method alone. The difference was statistically significant in N2 cases. When the mediastinal lymph node metastasis was detected on the ipsilateral side of the primary tumor or when the mediastinal lymph node swelling was smaller than 3 cm in diameter, the prognosis became better.

Carcinoma, Non-Small-Cell Lung↗
PubMed1987

[Clinical experience of 8MHz RF hyperthermia with radiotherapy of cancer of the uterine cervix].

During the period from September, 1983 to December, 1985, 12 patients with cancer of the uterine cervix were treated with 8MHz RF local hyperthermia, combined with radiotherapy. Out of 7 advanced cases, 3 achieved CR, 3 PRa (80-100% regression) and 1 PRb (50-80% regression) and out of the 5 cases with the recurrent cases, the results were: 3 PRa, 1 PRb, and 1 NC. It is worth noting that CR was obtained in huge tumors which are unable to be controlled by radiotherapy alone. In 3 cases, pain was experienced on the pubic bone, and in 3 other cases, skin burns, Grade II or III, occurred as complications.

Aged↗
PubMed1987

[Traumatic posterior fossa hematoma].

The traumatic posterior fossa hematoma was regarded as relatively rare thing, but recently, as the result of the prevalence of CT scanners, the number of reported cases is increasing. We report nine cases of traumatic posterior fossa hematoma. We divided into two categories: one was the acute epidural hematoma, the other was the acute subdural hematoma with cerebellar contusion. Five were cases of the acute epidural hematoma, three were cases of the acute subdural hematoma with cerebellar contusion and a case had both an epidural and a subdural hematoma. All the cases had struck the occipital region and had the occipital bone fracture. The prognosis of the five cases of the acute epidural hematoma was excellent, but that of the four cases of the acute subdural hematoma with cerebellar contusion was poor and they all died inspite of the removal of the hematoma executed in three cases. We estimated that the hitting forth was extremely strong in cases of the subdural hematoma with cerebellar contusion, and that the momentary deformity of the occipital bone might injure the cerebellum directly. Once a hematoma was produced in the posterior fossa, it oppresses the brainstem and causes the acute hydrocephalus, so the state of consciousness and respiration deteriorate suddenly. In cases of the acute epidural hematoma, appropriate surgical intervention could save the patients and resulted in good outcome. But in some cases of the fulminant type acute epidural hematoma of the posterior fossa caused by tearing the sinuses, though we have not experienced, patients die before the diagnosis and treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗