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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 649 records · Page 36Linked to original sources
PubMed1987

Independent protein kinases associated with the rat cerebral synaptic junction: comparison with cyclic AMP-dependent and Ca2+/calmodulin-dependent protein kinases in the synaptic junction.

Independent protein kinases in the synaptic junction (SJ) isolated from rat cerebrum were characterized. SJ showed a protein kinase activity, phosphorylating intrinsic proteins, even in the absence of cyclic AMP or Ca2+ plus calmodulin (CaM) exogenously added. The activity was affected neither by Ca2+ concentrations in the physiological fluctuation range nor by the addition of specific ligands such as glutamate, aspartate, acetylcholine, and concanavalin A. The activity was not due to cyclic AMP-dependent protein kinase in SJ, since the activity was not inhibited by an inhibitor protein for cyclic AMP-dependent protein kinase, and since synapsin I was not specifically phosphorylated whereas cyclic AMP-dependent kinase appeared to phosphorylate selectively the protein in SJ. Phosphorylation of SJ proteins by the independent kinases was about one-third of that of the Ca2+/CaM-dependent protein kinase intrinsic to SJ. The apparent Km for ATP was estimated to be 700 microM. Proteins of 16K Mr and 117K Mr were specifically phosphorylated under the basic condition (in the absence of the substances known to activate specifically protein kinases), as well as six other proteins both under the basic conditions and in the presence of Ca2+ and CaM. The phosphorylation of 150K Mr, 60K Mr, 51K Mr, and 16K Mr SJ proteins was enhanced after prephosphorylation of SJ proteins by intrinsic kinase in the presence of Ca2+ and CaM.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Follow-up study of 582 liver cirrhosis patients for 26 years in Japan.

A long-term follow-up study of liver cirrhosis (LC) was performed in 582 patients diagnosed by peritoneoscopy and liver biopsy in the 26 years from 1958 to 1984. The etiology of LC consisted of hepatitis B virus (HBV) in 21%, alcoholic in 39% and cryptogenic in 39%. Fifty-nine percent of patients had died. Causes of death were hepatocellular carcinoma (HCC 44%), liver failure (30%), rupture of esophageal varices (14%), gastrointestinal bleeding (4%) and non-liver-related causes (8%). HCC accounted for increasing percentages (68%) since 1980. In all groups classified by the etiology, the causes of death had the same order in incidence. The age of onset of LC increased by 10 years from 42 to 52 years old and the age of death by 15 years from 43 to 58 in the 26-year period. The cumulative survival rate improved over the period. The 50% survival year was 7.9 in total patients, and 7.0, 8.5 and 10.0 in the three periods 1958-64, 1965-74 and 1975-84, respectively. It was 9.5, 6.3 and 9.8 in HBV, alcoholic and cryptogenic, respectively. LC patients survived 40-44% of the life expectancy of the general population in Japan in all age groups. Cox's multiregression life-table method selected three important prognostic factors from 7 parameters: a poor prognosis with a history of heavy alcohol consumption and old age at onset, and a better prognosis with recent onset.

Actuarial Analysis↗
PubMed1987

Radiofrequency hyperthermia for malignant brain tumors: preliminary results of clinical trials.

Local hyperthermia by 13.56-MHz radiofrequency (RF) capacitive heating was evaluated in 16 patients with malignant brain tumors. Intracranial heating during operation was performed in 4 patients. RF applicators with a cooling system were placed on the cerebral convexity and medial brain surface with the tumor between them. RF power was controlled to maintain the brain temperatures under 40 degrees C. Under this condition, the highest temperature of each tumor varied from 44 to 49 degrees C. After heating for about 60 minutes, 2 tumors showed regression on computed tomographic (CT) scans. Extracranial heating was performed in 12 patients with cerebral glioblastoma. RF applicators were placed on the lateral sides of the scalp and applied to diametrically opposite sides of the tumor. To avoid the influence of the skull on RF conduction, we performed a bilateral craniectomy slightly larger than the applicator at the initial operation. Heating was performed for approximately 60 minutes at each session and was repeated twice a week for a total of 4 to 10 times in combination with radiation and ACNU chemotherapy. No anesthetic agent was used during heating. Brain temperatures were maintained under 42 degrees C. The scalp under the applicators remained at 28-35 degrees C during heating, and no heat injury of the scalp was observed after repeated heating. The highest temperatures of the tumor or cavity after tumor removal were 45-46 degrees C in 3 cases, 43-44 degrees C in 3 cases, 42-43 degrees C in 4 cases, and 40-41 degrees C in 2 cases, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Neoplasms↗
PubMed1987

Functional analysis of interleukin-2 in immune surveillance against brain tumors.

We studied the capacity of peripheral blood lymphocytes (PBLs) from patients with malignant brain tumors to produce interleukin-2 (IL-2) and to respond to IL-2. The role of IL-2 in the generation of T cells cytotoxic against tumor cells was also studied. PBLs from the patients with malignant brain tumors tended to produce a level of IL-2 lower than that in normal controls because of the decreased number of IL-2-producing T cells. Phytohemagglutinin activated PBLs from normal controls and the patients, however, responded equally well to IL-2. This indicates that the expression of IL-2 receptors is abundant in PBLs of these patients, although IL-2 production may be depressed. Furthermore, after incubation with IL-2, PBLs from the patients with malignant glioma exhibited higher natural killer activity and strong cytotoxicity against glioma cells. This increased cytotoxicity was evident by Day 3 of culture in IL-2 and remained effective for at least 2 days. These observations of antitumor cytotoxicity make IL-2 a likely candidate for use in adoptive immunotherapy.

Brain Neoplasms↗
PubMed1987

Long term results of ruptured aneurysms treated by coating.

We report the long term results of the treatment of 23 intracranial ruptured aneurysms by coating. Twenty-three patients treated by coating were followed for a mean period of 11.2 years. The mean interval between the last hemorrhage and the operation was 22.4 days. Ten aneurysms underwent total coating, 9 with Biobond and 1 with Aron Alpha. Thirteen aneurysms underwent partial coating, 11 with Biobond and 2 with Aron Alpha. Six aneurysms were reinforced partially by other materials, but no aneurysm was wrapped totally with these materials. Rebleeding occurred in 6 patients, of whom 5 died. The mean interval between coating and rebleeding was 4 years. All patients suffering rebleeding had been treated with Biobond, and 3 patients had undergone total coating of aneurysms. The risk of recurrent hemorrhage after total coating with Biobond was 33%. One rebleeding patient underwent a second operation 10.5 years after total coating of the aneurysm. Biobond was found only at the tip of the aneurysmal sac. From these results, reinforcement of ruptured aneurysms with Biobond seems to be of little value, and a more reliable method must be developed for aneurysms that cannot be clipped.

Adult↗
PubMed1987

[Immunohistological analysis of infiltrating lymphocyte subpopulations in gliomas and metastatic brain tumors].

Subpopulations of infiltrating lymphocytes were studied by immunohistological method using monoclonal antibodies in gliomas and metastatic brain tumors. Thirteen specimens from 8 glioma patients, and 7 specimens from 3 metastatic brain tumor patients were used. No special therapy for brain tumor had been performed in these cases, but 3 glioma patients and all metastatic brain tumor patients had received steroid hormone. Frontal lobe obtained from the autopsy case of chest trauma was served as a normal control. Frozen sections were stained with avidin-biotin peroxidase complex method using Leu-series monoclonal antibodies for pan T-cells (Leu-1), cytotoxic/suppressor T-cells (Leu-2 a), helper/inducer T-cells (Leu-3 a) and B-cells (Leu-12). Lymphocyte infiltrates were quantitated by counting positively stained cells in 13 glioma and 7 metastatic brain tumor specimens. In normal frontal lobe, only a few T-cells infiltrated around several blood vessels in the parenchyma and subarachnoid space. But in the cases of glioma, many perivascular lymphocytic infiltrates were found and in the cases of metastatic brain tumor, many lymphocytes were found diffusely in the interstitial area between nests of tumor cells. Most of these lymphocytes were T-cells and B-cells were scarce, and Leu-2 a and Leu-3 a positive cells intermingled with each other. Len-3 a/2 a ratio ranged from 0.2 to 0.9 in the half of gliomas and 1.5 to 3.6 in another half of gliomas, three of which were treated with steroid hormone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Suppression of acute experimental allergic encephalomyelitis in Lewis rats with cerebral contusion].

We previously reported that the thymolysis was observed in acute experimental allergic encephalomyelitis (EAE) rats immunized with brain tissue homogenates in complete Freund adjuvant. This observation has led us to suppose that the central nervous system (CNS) has high antigenicity for self. To keep from the high antigenicity of CNS, the blood brain barrier (BBB) and cerebrospinal fluid (CSF) which maintain CNS in isolated state are essential for self. If the BBB is destroyed and brain tissue is disseminated in CSF, is oneself sensitized by CNS? In this experiment, we produced cerebral contusion in rats and the BBB was partially destroyed and brain tissue was disseminated in CSF. No clinical signs of EAE were observed by cerebral contusion was exposed to encephalitogen one week later, EAE was remarkably suppressed compared with those in controls or sham operated groups (p less than 0.001). Almost 80% of the rats with cerebral contusion showed no response to EAE. These results seen to show that self is sensitized by autologous brain tissue and CNS has high antigenicity.

Acute Disease↗
PubMed1987

[Clinical significance of beta 2-microglobulin and carcinoembryonic antigen in intracranial tumors].

Beta 2-microglobulin (beta 2-MG) levels were determined in serum, cerebrospinal fluid (CSF), and tumor cyst fluid obtained from patients with a variety of intracranial tumors. In addition, a simultaneous determination of the carcinoembryonic antigen (CEA) was carried out in some patients. The beta 2-MG levels were elevated in 11/101 intracranial tumors, including glioma (4/34), non-glial tumors (1/18), malignant lymphoma (2/18), and metastatic brain tumors (4/31). There were no significant differences in the beta 2-MG levels of serum among the different patient groups. On the other hand, the beta 2-MG levels in CSF were significantly higher in patients with malignant lymphoma and metastatic brain tumors than in those with glioma and non-glial tumors. Fifteen (83.3%) of 18 patients with malignant lymphoma and 6(25.0%) of 24 patients with metastatic brain tumors showed increased the levels of beta 2-MG in CSF. The beta 2-MG levels in the tumor cyst fluid of 11 intracranial tumors exceeded normal serum levels in all but two patients. When the CEA levels in the serum and CSF were measured simultaneously, meaningful differences between malignant lymphoma and metastatic brain tumors were clearly observed. The highest incidence and highest levels of the CEA in serum and CSF were only noted in patients with metastatic brain tumors. Conversely, the serum CEA was slightly raised in 11.8% of malignant lymphoma and the levels of CEA in CSF were within normal range in all these patients. Serial determination of CSF beta 2-MG in patients with malignant lymphoma correlated well with their clinical findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Neoplasms↗