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T Mitani

Publications and source records attributed to T Mitani.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Measurement of small bowel transit time in dogs with acetaminophen and indocyanine green].

We developed an experimental method to measure the gastric and the small bowel transit times in dogs without using X-ray nor radioisotopes. The dog with the ileostomy was given food containing acetaminophen (APAP) and indocyanine green (ICG), then we sampled blood and ileal contents of the dog. We could measure the gastric transit time by detecting plasma APAP and the small bowel transit time by detecting ICG in the intestinal contents. Using this experimental system, we examined the times after feeding milk or solid meal. The gastric transit time after taking solid meal was longer than that after taking milk, but this difference was not significant, and the small bowel transit time after taking solid meal was significantly shorter than that after taking milk.

Acetaminophen↗
PubMed1991

[Dynamic MRI of hepatocellular carcinoma with portal vein tumor thrombus].

Dynamic MRI with injection of Gd-DTPA was performed in 7 patients with hepatocellular carcinoma associated with portal vein tumor thrombus. A portal vein tumor thrombus was clearly visualized as a low intense structure. The segment supplied with this portal vein shows high intensity, probably due to the decrease in portal blood flow and compensated arterial blood flow. A tumor itself, located in this segment, was shown as a low intense area. Thus dynamic MRI is a useful method for differentiating the tumor from the surrounding nontumorous tissue with decrease in portal flow.

Aged↗
PubMed1990

[Dynamic MRI of liver tumors--evaluation by inversion recovery snap shot FLASH MR imaging].

We have studied 20 patients with liver tumor (hepatoma 12, hemangioma 6, metastatic tumor 2) using inversion recovery snap shot FLASH dynamic MR imaging. After intravenous injection of Gd-DTPA, serial 17 images were obtained during 7 minutes. Hepatoma showed central enhancement on early phase (0-20 sec) in 11 patients and absent or less enhancement than surrounding liver parenchyma on late phase (1-3 min) in 12 patients. Hemangioma showed peripheral enhancement on early phase in 6 patients, and slight to moderate enhancement on late phase in 5 patients. Peripheral slight enhancement were seen on late and delayed (5-7 min) phase in two patients with metastatic liver tumor. These characteristic enhancement patterns should facilitate differential diagnosis of liver tumors.

Aged↗
PubMed1990

A platelet membrane glycoprotein (GP) deficiency in healthy blood donors: Naka- platelets lack detectable GPIV (CD36).

It has recently been shown that the Naka antigen, which is absent in 3% to 11% of Japanese blood donors, is expressed on platelet glycoprotein IV (GPIV; CD36) (Tomiyama et al, BLOOD, 75:684, 1990). In the present studies, flow cytometry was used to distinguish differences in the reactivity of Naka+ and Naka- platelets with both OKM5, a monoclonal antibody that recognizes an epitope on GPIV, and with polyclonal anti-GPIV antibody. OKM5 was also used to screen 871 platelet concentrates prepared from healthy US blood donors. Three of these showed markedly deficient binding of 125I-OKM5 or an incidence of 0.34%. Two of these donors were re-accessed and showed less than 1% binding of 125I-OKM5 as compared with 10,300 +/- 1,500 binding sites per platelet in controls (n = 4). Platelets from these two US donors were radiolabeled (125I, 3H) and compared with control platelets and with platelets from Japanese Naka+ and Naka- donors by crossed immunoelectrophoresis, protein blots, immunoprecipitation, and two-dimensional gel electrophoresis. GPIV could not be detected by any of these techniques in the Naka- platelets nor in the donors whose platelets showed deficient binding of OKM5. These results suggest that GPIV functions as an isoantigen rather than an alloantigen in immunizing Naka- platelet recipients. This is the first report of the absence of a major platelet membrane GP in healthy blood donors.

Antibodies, Monoclonal↗
PubMed1990

Identification of the platelet-specific alloantigen, Naka, on platelet membrane glycoprotein IV.

We describe the membrane localization of a new platelet-specific alloantigen, designated Naka, that is involved in refractoriness to HLA-matched platelet transfusions. By indirect immunoprecipitation, anti-Naka antibody precipitated a single, radiolabeled platelet membrane protein with a molecular weight (mol wt) of 91 Kd from Naka-positive platelets. When radiolabeled Naka-negative platelets were used as a source of target antigens, no radiolabeled proteins were precipitated. The analyses using nonreduced-reduced two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and using rabbit antiglycoprotein (GP)IV demonstrated that this protein corresponds to GPIV (alternatively GPIIIb). Furthermore, in dot immunobinding, anti-Naka antibody bound to purified GPIV. Our results provide definitive evidence that the Naka alloantigen is carried on GPIV. These results also demonstrate that, on occasion, antibodies against GPIV may play an important role in refractoriness to platelet transfusions.

Antigens, Surface↗
PubMed1990

The tonsillar immune system: its response to exogenous antigens.

The palatine tonsil is the only lymphoid organ directly exposed to the outside environment. This characteristic anatomical feature appears to be immunologically significant with the defence activity primarily directed against exogenous antigens. However, the palatine tonsil is also often the site of secondary diseases, such as focal infections. This study investigated how the tonsil responds to horseradish peroxidase (HRP) dropped into the crypts and the effects of this response on the regional lymph node and the kidney as a distant organ. HRP entered through the microcrypts was phagocytosed by macrophages, gathered mostly around the vessels and emigrated to the regional lymph nodes. Anti-HRP antibody-producing cells were observed not only in the tonsil but also in the regional lymph node. In this long-term study with repeated immunization, fusion of the epithelial foot process and reduction of the anionic charge in the glomerulus were often found electron microscopically. This investigation suggests that the tonsil has important roles in the defence activity in relation to the general immune system; otherwise it becomes a primary site for focal infections.

Animals↗
PubMed1990

Effects of proxigermanium on interferon production and 2',5'-oligoadenylate synthetase activity in the lung of influenza virus-infected mice and in virus-infected human peripheral blood mononuclear cell cultures.

Proxigermanium (SK-818) is a synthesized organic germanium compound having various biological activities. The effects of proxigermanium on interferon (IFN) production in mice infected with influenza virus and virus-infected human peripheral blood mononuclear cells (hPBMC) were investigated. Proxigermanium alone did not induce IFN production in normal mice or in hPBMC without viral infection. On the other hand, proxigermanium enhanced alpha/beta IFN production in viral-infected mice and hPBMC. Since proxigermanium is known to have antiviral activity in vivo but not in vitro, it is likely that the IFN production augumenting activity of proxigermanium is involved in its antiviral activities.

2',5'-Oligoadenylate Synthetase↗
PubMed1989

Recognition of rat liver and kidney nuclear T3 receptors by an antibody against c-erb A peptide.

It has been reported that c-erb A encodes nuclear T3 receptors (NT3R). Based on the sequence of c-erb A cDNA, we synthesized a polypeptide consisting of 15 amino acids, the sequence of which has high homology between c-erb A alpha 1 and beta. The antibody against this c-erb A peptide not only immunoprecipitated rat liver and kidney NT3R but also inhibited T3 binding to NT3R. In a displacement study, the inhibition of [125I]T3-binding by the antibody was parallel to that by T3 in terms of the concentration of the competitor added in the incubation mixture. Scatchard analysis revealed that the antibody decreased the value for the association constant in a dose dependent manner. The antibody did not bind T3 itself. The results show that the antibody against c-erb A peptide recognizes rat liver and kidney NT3R and that the sequence encoding this peptide, the closest carboxyl-terminal of c-erb A may be critical or at least closely related to the hormone binding.

Animals↗
PubMed1989

A new platelet-specific antigen, Naka, involved in the refractoriness of HLA-matched platelet transfusion.

Serum from a thrombocytopenic patient who was refractory to the transfusions of HLA-matched platelets contained a platelet-specific alloantibody, anti-Naka. Immunofluorescence analyses revealed that the Naka antigen defined by the serum was expressed exclusively on platelets and its distribution was different from P1A1, Baka, Yuka or Yukb. Analysis by Dr. von dem Borne's group revealed the Naka was also different from Koa, Kob or Zwb. Family studies showed that the Naka antigen was inherited as an autosomal codominant trait. Its antigen frequency in the Japanese population was over 97%. The results of the enzyme immunoassay using monoclonal antibodies for antigen immobilization showed that the Naka epitope did not appear to reside on GPIIb/IIIa or Ib. The transfusions of Naka-compatible platelets improved the patient's thrombocytopenia.

Adult↗
PubMed1989

[Analysis of recurrences of meningiomas following neurosurgical resection].

A clinical and pathological study of 124 surgically treated patients with intracranial meningiomas was carried out to evaluate factors influencing recurrence. The patients ranged in age from 8 years to 75 years. Thirty-five (28.2%) were males and 89 (71.8%) were females. Recurrences occurred in 18 patients, once in eleven, twice in six, four times in one. The period from first surgery to recurrence ranged from 5 months to 84 months (mean 29.9 months). Age, sex, site of tumor, surgical grading, and histology were selected as analytic factors. Simpson's classification was used as surgical grading. All the patients with recurrences were younger than 60 years old, and particularly in the patients who were younger than 40 years the recurrence rate was high. Mean age of the group with recurrence was 41.8 years, which was significantly younger than that of the group without recurrence (52.0 years). In the group with recurrence, ten were males and eight were females. The recurrence rate was 28.6% in males, and was 9.0% in females. Thus the recurrence rate was significantly higher for males than for females (p = 0.016). It also seemed that the period from first surgery to recurrence was earlier for males than for females. The patients with meningiomas at posterior fossa or sphenoid ridge often had recurrences, and the recurrence rate was 29.4% and 21.7%, respectively. But these recurrence rates were not significantly higher than those at other sites. On the contrary, no recurrences occurred at convexity, intraventricle, and olfactory groove.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Intracerebral hemorrhage immediately following the operation of chronic subdural hematoma].

Complications following the operations for chronic subdural hematoma include recurrence of the hematoma, infection, seizure, and failure of the brain to expand due to cerebro-cranial disproportion. This report presents cases with intracerebral hemorrhage which is relatively rare complication. In case 1, a 35-year-old man developed status epilepticus immediately after the operation for chronic subdural hematoma. An emergency CT scan revealed acute brain swelling, and still, after the external decompressive craniotomy, CT scan showed severe brain swelling with subcortical diapedetic hemorrhage. In case 2, a 78-year-old woman whose CT scan had shown bilateral CSH and brain herniation, demonstrated intracerebral hemorrhage in the medial occipital lobe when examined post-operatively by CT scan. It is possible that the mechanisms of intracerebral bleeding following the operation for CSH are 1) diapedesis through increased permeability of parenchymal blood vessels due to the sudden increase in cerebral blood flow following the existence of longstanding extracerebral mass, and 2) hemorrhagic infarction due to recanalization of posterior cerebral artery compressed by the herniating medial temporal lobe. We should therefore avoid sudden decompression in the management of the cases which showed pre-operative consciousness disturbance or abnormal low or high density on CT scan, because these findings may be preoperative indications of brain fragility.

Adult↗