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Biomedical subjects

T Hanamura

Publications and source records attributed to T Hanamura.

At least 37 records · Page 2Linked to original sources
PubMed1987

A novel concept on the pathogenetic mechanism underlying ischaemic brain oedema: relevance of free radicals and eicosanoids.

A survey on literature reports and our own experimental studies on the pathogenetic mechanisms underlying ischaemic brain oedema is given and a new concept proposed. In regional incomplete ischaemia the lipoxygenase activity is enhanced, presumably caused by an increase of free radicals and hydroperoxides, leading to an enhancement of endothelial Na+, K+-AtPase and increased sodium and water transport from blood to brain. The aggravation of brain oedema and post-ischaemic hypoperfusion following recirculation appears to be mainly due to an activation of the cyclo-oxygenase pathway with release of oxidants from PGG2, which causes non-specific but detrimental damage to the endothelial and parenchymal cells. This new concept may open future perspectives in treatment which are briefly discussed.

Animals↗
PubMed1987

Human colony-stimulating factor-producing lung cancer tissue releases a differentiation-inducing factor for human leukemic cells.

Human lung cancer that induced marked granulocytosis in both the patient and tumor-transplanted nude mice (G2 mice) and from which conditioned medium (G2-T-CM) exhibited human and mouse active colony-stimulating activity (CSA) has been reported (K. Ikeda et al. Cancer Res 1985; 45:4144-4249). Recently, we found differentiation-inducing activity (DIA) in G2-T-CM, which differentiated human promyelocytic leukemic cells (HL-60) to macrophage-like cells. Differentiated HL-60 cells were considered to be mature macrophages as judged by the positivity of butyrate esterase activity, the acquisition of Fc receptor, and the increment in capacity of phagocytosis and nitroblue tetrazolium reduction. The DIA in G2-T-CM was not attributed to interferons known to have DIA, because interferon activity was not found in G2-T-CM by bioassay (less than 4 U/ml) and by radioimmunoassay for gamma-IFN (less than 0.1 U/ml). Molecular weight of DIA was 36,000 Da and separated from CSA of which molecular weight was 22,000 Da by gel filtration on Sephadex G-150. DIA and CSA were also separated on chromatofocusing chromatography, because isoelectric point of DIA was mainly less than 4.0 and that of CSA was 4.3-5.7. This DIA was stable after heat treatment (56 degrees C for 30 min or 100 degrees C for 10 min) and in acidic condition (pH 2.0 for 24 hr). G2-T-CM is a good source of differentiation-inducing factor for further purification and molecular cloning.

Biological Products↗
PubMed1987

[Mechanism of deafferentation pain--experimental research using spinal root resection model].

In rats, autotomy of the digits following dorsal root resection has been observed by many researchers and is considered as an animal model of deafferentation pain. Using C5-Th 1 root resection model of rats, we investigated the role of the ventral roots and pain experience given before deafferentation in the development of autotomy. Male Sprague-Dawley rats of eight weeks old, weighing about 200 g, were used. Animals were divided into two major groups; dorsal root resection group and total (both ventral and dorsal) root resection group. Each group was further divided into several sub-groups, according to the use of formalin injection, before or after surgery, and to the side of formalin injection, the forearm of the affected (root resection) side or unaffected side or of both sides. In pre-injection groups, 0.1 ml of 5% formalin was given subcutaneously on the forearm one hour before surgery. In the postinjection groups, formalin was given within one hour after surgery. Dorsal root resection group without formalin injection was used as control. Under anesthesia with intraperitoneal injection of nembutal, left C 5-Th 1 dorsal root resection was performed by C 4-Th 1 laminectomy and left C5-Th 1 total root resection by opening of the corresponding vertebral foramen. After surgery, we checked neurological findings, systemic condition and local changes of all the extremities everyday during the first week and once a week thereafter for at least three months. In control groups, autotomy was not observed at all during the observation period of three months.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1987

Differentiation-inducing factor for a human leukemic cell line produced by colony-stimulating factor producing human lung cancer tissue.

We have found that medium conditioned by a colony-stimulating factor producing tumor derived from a granulocytosis case with lung cancer contained a factor to differentiate a human promyelocytic leukemic cell line (HL-60) to macrophage-like cells that were butyrate esterase-positive and had phagocytosing activity and membrane Fc receptors. This differentiation-inducing factor was not active for a human myeloblastic cell line (KG-1), and was separated from a colony-stimulating factor by its molecular weight and isoelectric point. The conditioned medium did not contain a detectable amount of gamma interferon when tested by bioassay as well as by radioimmunoassay. This is the first report that a human lung cancer tissue produces not only a colony-stimulating factor, but also a differentiation-inducing factor. The conditioned medium is considered to be a good source of differentiation-inducing factor.

Animals↗
PubMed1986

[A case of growth hormone-producing adenoma presenting as a non-functioning tumor at recurrence].

The authors report a case of recurrent pituitary adenoma, which changed its endocrinological function from GH producing to non-functioning. A 37-year-old woman was admitted to our hospital complaining of headaches, amenorrhea and acromegalic features. Skull X-rays showed marked ballooning of the sella turcica and mild thickening of the calvarium. X-rays of the hands and feet revealed moderate acromegalic changes. On pneumoventriculography, the tumor elevated the floor of the third ventricle. The serum GH level was 29.3 ng/ml, which did not respond to insulin induced hypoglycemia. Radical removal of the tumor was performed through a right frontal craniotomy. Histologically, it was diagnosed as a pituitary eosinophilic adenoma. Immunostains revealed the presence of many GH positive cells in the adenoma. Since the post-operative GH levels were still high (12-16 ng/ml), irradiation to the sellar region was carried out. The serum GH concentration gradually decreased to the normal level in one year after the irradiation. At that time no sellar tumor could be found on CT scans. The patient had been well for six years until she noticed hearing impairment of her right ear. She was re-admitted about seven years after the first admission because of cerebellar ataxia and hearing loss. CT scans revealed a recurrent tumor extending from the sellar region to the right cerebello-pontine angle. Serum GH levels on admission were within normal range (3-4 ng/ml). The tumor was partially removed by suboccipital craniectomy. Pathologically, the tumor was reported as a pituitary chromophobe adenoma. With immunostains, no GH positive cells could be found in the adenoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗
PubMed1984

[Experimental study of acrylic resin coated gentamicin tablets for local antibiotic therapy].

Gentamicin tablets were prepared and evaluated for local antibiotic therapy. Two types of tablet were used. One, a slow release tablet, was coated with acrylic resin (Eudragit R.S.) and another was non-coated. The release of gentamicin from the coated tablets can be controlled by changing the thickness of the film coating. The thickness of the film coating was adjusted to release gentamicin within three weeks when placed in Ringer's solution. Coated tablets were inserted into the bone marrow of rabbits. Thereafter, daily excretion of gentamicin was measured in the urine for three weeks. Constant excretion of gentamicin was seen for ten to fourteen days, which suggests the release of gentamicin from the bone marrow. Plasma concentrations were very low, thus precluding side effects. Non-coated tablets were inserted to the bone marrow by the same method as above. Plasma concentrations of gentamicin peaked in one hour and then rapidly decreased. This pattern is similar to that seen with intramuscular administration. As acrylic resin was non-absorbable material in vivo, the tissue reactions around coated tablets were examined. Histological findings at three weeks, six weeks and six months after insertion, respectively, did not show any severe tissue reactions. The possible use of local therapy by coated antibiotic tablets for bone infections is discussed.

Acrylic Resins↗
PubMed1983

Bragg-peak proton-beam therapy for arteriovenous malformations of the brain.

Patients with arteriovenous malformations of the brain, who are subject to disabling or fatal recurrent hemorrhage, seizures, severe headache, and progressive neurologic deficits, may be considered unsuitable for conventional therapies (craniotomy with excision or embolization), usually because of the location, size, or operative risk of the lesion. We have treated such patients with stereotactic Bragg-peak proton-beam therapy and report the follow-up of 74 of the first 75, 2 to 16 years after treatment. Proton-beam therapy is intended to induce subendothelial deposition of collagen and hyaline substance, which narrows the lumens of small vessels and thickens the walls of the malformation during the first 12 to 24 months after the procedure. Two deaths from hemorrhage occurred in the first 12 months after treatment, but no lethal or disabling hemorrhages occurred after this interval. Seizures, headaches, and progressive neurologic deficits were in most cases arrested or improved. Bragg-peak proton-beam therapy appears to be a useful technique for treatment of intracranial arteriovenous malformations, especially those that are unsuitable for treatment by other methods.

Adolescent↗
PubMed1983

[The migration of cefotiam to cerebrospinal fluid].

The concentration of cefotiam (CTM), a newly synthesized cephem derivative antibiotic in serum and cerebrospinal fluid after single intravenous treatment was determined and its utility in the field of cerebral neurosurgery was studied. 1. One gram or 2 g of CTM was intravenously administered for 1 time to 10 patients admitted to our department. Dose dependency was observed in the progress of the mean serum concentration. There was no difference in the specific rate of constant, and the ratio of AUC between the group treated with 1 g and the one with 2 g was 1:1.9. The biological half-lives of the elimination phase for both dose levels were about 1.1 hours. 2. Disparity was recognized in the cerebrospinal fluid concentration in spite of the dose dependency. Although a case with comparatively high value of 1.37 micrograms/ml at 60 minutes after administration were seen in the 1 g treatment group, generally the migration concentration was low. Good cerebrospinal fluid concentration was attained in all of the cases in the 2 g treatment group, and the peak values ranged from 0.59 to 10.16 micrograms/ml. 3. The concentration ratio of cerebrospinal fluid to serum in the 2 g treatment group elevated till 360 minutes after administration, and the maximum values ranged from 15.8 to 89.8%. 4. The migration to the cerebrospinal fluid was faster in cases with slight inflammation than those without inflammation in the 2 g treatment group. 5. It was assumed that the prophylactic effect of CTM 2 g administration against staphylococci, streptococci and Klebsiella pneumoniae which are the major causative organisms can be expected in postoperative infection in the field of cerebral neurosurgery.

Adult↗
PubMed1978

A case of epidermoid of the fourth ventricle.

The case of woman, aged 52, who had a fourth ventricular epidermoid, which eluded definite diagnosis for six years because of spontaneous remissions, is reported. Computed tomography may be misleading in such cases with spontaneous remission of symptoms because of the low electron density of the tumor which is not enhanced by intravenous contrast medium. Other diagnostic means such as ventriculography should not be neglected.

Cerebral Ventricle Neoplasms↗
PubMed1978

Boron-neutron capture therapy in relation to immunotherapy.

The essential feature of tumour therapy rests upon host-tumour interaction. To achieve therapeutic effects, a prerequisite to immunotherapy is the reduction of tumour cells in the host's body. Such measures should not be immunosuppressive. Cytotoxic chemotherapy is not appropriate in this regard. Supraradical surgery and non-specific radiotherapy are not desirable for preservation of nervous function, if their immunosuppression is not as severe as cytotoxic substances. Boron-neutron capture therapy is a highly specific and least immunosuppressive means of reducing tumour cells of the central nervous system. A brief introductory review of basic research is presented. The interim clinical results are: (i) Treatment of recurrent glioblastoma: Survival extension obtained by neutron capture therapy is 21.9 +/- 7.2 mos in contrast to that obtained by conventional treatments of 6.7 +/- 0.6 mos (p less than 0.001), (Total survival 26.3 +/- 6.7 mos); and (ii) only three patients including two glioblastoma cases were treated with neutron by the same surgeon who, by performing the first tumour operation, had the advantage in topographic knowledge for determining the radiation field. They survived 4, 5, and 6 years in almost fully active conditions. The new Musashi Institute of Technology Reactor Thermal Neutron Therapy Facility and the increased domestic production of boron-10 isotope have enlarged the therapeutic capacity to two dozen patients a year.

Adolescent↗