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Biomedical subjects

T Tanabe

Publications and source records attributed to T Tanabe.

At least 451 records · Page 25Linked to original sources
PubMed1989

Combined method of fluorescence tracer technique and PAP immunohistochemistry for discrimination of the transplanted cells.

The retrograde fluorescence tracer, True Blue (TB), was injected into the forebrain septal area of neonatal rats. After 3 to 6 days the brains of these animals were carefully removed and placed in ice-cold sterilized physiological saline containing 1% glucose. Under the surgical microscope, one or two pairs of mesencephalic tissue samples, each containing a dorsal raphe nucleus, were punched out and transplanted into the third ventricle of a 5,6-DHT-pretreated adult rat. One month after transplantation, all animals were perfused and their brains sectioned using a cryostat. The sections were examined using a fluorescence microscope, and then processed for serotonin immunohistochemistry. The grafts were found to be successfully implanted and connected with the middle portion of the third ventricle. Four types of neurons, i.e., TB-labeled, serotonin-labeled, both TB- and serotonin-labeled, and non-labeled neurons, were detected in the grafts. This double-labeling method is considered to be a useful technique in characterizing the neurons in grafts which consist of a heterogeneous cell population.

Animals↗
PubMed1989

Leukotriene A4 hydrolase from guinea pig lung: the presence of two catalytically active forms.

Leukotriene A4 hydrolase was purified to apparent homogeneity from the guinea pig lung. The molecular weight was determined to be 70 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme exhibited two active forms with different pI values (5.7 and 5.4) depending on the presence or absence of SH-reducing reagents during purification procedures. No significant differences were observed between both forms of the enzyme as regards the catalytic properties. The N-terminal 20 amino acid sequence (PEVVDTXSLASPATVXRTKH) showed a 90% identity to the human enzyme with a constitutive substitution of Ile-3 and Ser-14 (human) by Val-3 and Thr-14 (guinea pig), respectively.

Amino Acids↗
PubMed1989

Immunohistochemical study of ras p21 expression in human gastric cancers and benign lesions.

Expression of ras p21 in human gastric cancers, benign lesions and normal tissues was immunohistochemically evaluated by the avidin-biotin peroxidase complex (ABC) method with anti-ras p21 monoclonal antibody rp-28. Positive p21 immunoreactivity was shown in 23 (77%) of 30 gastric cancers, in 13 (48%) of 27 benign lesions and in 10 (22%) of 46 normal mucosa cases. Among them, strong staining was demonstrated only in 11 (37%) of 30 gastric cancers, but not in benign lesions and normal tissues. Cases showing more than 20% positive cell ratio were observed in 22 (73%) gastric cancers, in 11 (41%) benign lesions and 6 (13%) normal mucosa cases. Further, intracellular distribution of ras p21 is heterogeneous in gastric cancers, while it is homogeneous in benign lesions or normal tissues. The ABC method with rp-28 could be helpful for clinical differential diagnosis between gastric cancers and benign lesions by investigating three factors: staining intensity, positive cell ratio and intracellular distribution of ras p21.

Adenocarcinoma↗
PubMed1989

Possible roles of partial sequences at N- and C-termini of amelogenin in protein-enamel mineral interaction.

The purpose of this study was to assess the functional significance of homologous sequences of mammalian amelogenins at their N- and C-termini. A porcine 5-kDa fragment corresponding to the N-terminal 45 residues of amelogenins was purified from the secretory enamel. The decapeptide TDKTKREEVD corresponding to the C-terminal 10 residues of amelogenins was synthesized according to conventional solid-phase procedures. The inhibitory activity of both moieties on apatite crystal growth was determined in a supersaturated solution having an ionic composition similar to that of the fluid phase separated from porcine secretory enamel. The 5-kDa amelogenin fragment was sparingly soluble in neutral solutions and (in condensed forms because of aggregation) showed no significant inhibition of crystal growth, whereas the fragment molecules pre-adsorbed onto the seed crystals yielded modest inhibition of hydroxyapatite precipitation. However, their inhibitory activity was significantly lower than that of parent porcine amelogenin (25-kDa molecular mass). The high solubility of synthesized decapeptide allowed us to determine the adsorption isotherm onto hydroxyapatite at 37 degrees C, at an ionic strength similar to that of the enamel fluid. The obtained adsorption isotherm was described by a Langmuir model; the adsorption affinity and the maximum adsorption sites were 6.2 mL/mumol and 0.53 mumol/m2, respectively. As expected from the low adsorption affinity, the peptide showed a much weaker inhibition of apatite crystal growth than the parent amelogenin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMed1989

Development of a ceramic heart valve.

A durable and thromboresistant ceramic heart valve comprised of a single crystal alumina disk and titanium nitride (TiN) valve ring has been developed. Blood compatibility was examined by scanning electron microscopy (SEM) examinations of the valves implanted in sheep for 35 (#1), 26 (#2), 20 (#3), 23 (#4), and 26 (#5) days. The single crystal alumina and TiN surfaces were free of platelet aggregation or fibrin networks, except for some depositions of fibrin and platelets on the outflow TiN ring in #3, and isolated red cells on the outflow TiN ring in #5. Durability testing under high pressure (1750 mmHg = 233 KPa) pulsatile conditions showed that the safety factor of the ceramic valve was more than seven times greater than anticipated. The ceramic valve is promising as an artificial heart valve.

Animals↗
PubMed1989

A trial of the 21-aminosteroid U74006F in a primate model of chronic cerebral vasospasm.

The efficacy of U74006F in the prophylaxis of chronic cerebral vasospasm (VSP) was evaluated in a randomized, double-blind, placebo-controlled trial. Forty cynomolgus monkeys were divided by restricted randomization into 2 treatment groups of 20. Five animals from each treatment group were randomized into subgroups 1 and 2. The animals of subgroup 1 were studied pathologically. Brain biopsies of the animals in subgroup 2 were performed and studied with high-performance liquid chromatography (HPLC). The remaining 20 animals supplemented the number studied angiographically. Significant VSP (P less than 0.05) was detected in the majority of vessels from the clot site (right) of both treatment groups. Electron microscopy results showed positive correlation with the angiographic data. When comparing the effects of U74006F to those of the placebo at day 7, there was a significant difference (P less than 0.05) in the degree of VSP in the right extradural internal carotid and right middle cerebral arteries. This resulted from a greater degree of VSP in placebo animals. Two animals developed delayed ischemic deficits, one from each group. The infarct of the U74006F animal was smaller than the infarct in the placebo animal. Although overall changes in phosphagen levels did not reach statistical significance, HPLC analysis of the cortical biopsies did show a decrease in the ATP/ADP +/- AMP ratio of 54% in placebo animals and only 7% in animals receiving U74006F. The middle cerebral arteries of 2 animals were also studied with HPLC.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Long-term prognostic assessment of ventricular tachycardia with respect to sudden death in patients with and without overt heart disease.

The purpose of this study is to investigate the long-term prognosis of ventricular tachycardia (VT) mainly with respect to sudden death (SCD) in patients with ischemic heart disease (IHD), idiopathic cardiomyopathy (ICM), miscellaneous heart disease (MHD) and idiopathic ventricular tachycardia (IVT). The study included 117 patients with VT (80 male, 37 female). The number of patients with IHD, ICM, MHD and IVT were 40, 18, 26 and 33, respectively. Follow-up was conducted by means of a mailed standardized questionnaire. The mean follow-up period was 46.8 +/- 32.0 months (range from 6 to 125 months). In 24 out of the 117 patients the cause of death was SCD, in 9 there was no sudden cardiac death and in 5 no cardiac death. The other 76 were surviving. The number of SCD in IHD, ICM, MHD and IVT was 14/40 (35%), 4/17 (24%), 6/25 (24%) and zero (0%), respectively. The number of having had syncope in IHD, ICM, MHD and IVT was 19/40 (48%), 7/18 (39%), 6/26 (23%) and 6/33 (18%), respectively. Out of the 19 IHD patients with syncope, 15 had had ventricular fibrillation (VF). As for IVT with syncope, only one of the 6 had VF, which was induced by a disopyramide injection. In IVT, the patients with syncope had a significantly higher VT rate than those without syncope (p less than 0.01). There were no significant differences in the electrocardiographical high risk parameters for SCD, the age, follow-up periods, the presence or absence of VF and ejection fraction between the SCD and the surviving groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Immunocytochemical localization of amelogenins in the deciduous tooth germs of the human fetus.

The immunocytochemical localization of amelogenins in the developing deciduous tooth germs of 6-month-old human fetuses was investigated by the protein A-gold method using an antiserum against porcine 25K amelogenin. The inner enamel epithelial cells and underlying matrix showed no amelogenin-like immunoreactivity. Distinct immunoreactivity was initially shown by fine fibrils found beneath the intact basal lamina of preameloblasts at the early differentiation stage. At the late differentiation stage, amelogenin-like immunoreactivity was shown by a fine granular material within the extracellular matrix as well as by the Golgi apparatus, secretory granules, lysosomal structures, coated vesicles, and coated pits of preameloblasts with a disrupted basal lamina. At the formative stage, the localization of immunoreactivity in secretory ameloblasts was similar to that in preameloblasts during the late differentiation stage. However, immunopositive coated vesicles and coated pits were only found at the early stage of matrix formation. The calcified enamel matrix and stippled material showed intense immunoreactivity. Immunocytochemical labeling of the enamel matrix appeared as a gradient, decreasing from the enamel surface to the dentinoenamel junction. No maturation stage of ameloblasts existed in the tooth germs examined. In predentin and dentin, amelogenin-like immunoreactivity was occasionally detected on odontoblasts and their processes, but odontoblasts and cells of the stratum intermedium contained no immunoreactive elements. These findings confirmed that the secretory ameloblast in the human deciduous tooth germ is responsible for the synthesis and secretion of enamel proteins.

Amelogenin↗
PubMed1989

Immunohistochemical studies on the development of tyrosine hydroxylase- and serotonin-immunoreactive neurons in fetal dorsal raphe tissue transplanted into the anterior eye chamber of adult rats.

Pieces of tissue containing dorsal raphe nuclei of fetal rat brains were transplanted into the anterior eye chambers of adult rats. The differences between the developmental patterns of catecholaminergic and serotonergic neurons--especially the extension of their axonal processes--in the grafts were immunohistochemically examined using tyrosine hydroxylase (TH) and serotonin antisera. At an early stage after transplantation (3 days), TH-positive neurons appeared in grafts that had and had not been pretreated with a monoamine oxidase inhibitor (MAOI, Nialamide), while serotonin-positive neurons were demonstrated only in the grafts that had undergone MAOI pretreatment. Morphological differences in the growth pattern in the experimental milieu between the TH and serotonin neurons were also demonstrated: at this early stage, the somata of the TH neurons were multipolar and stellate shaped and possessed several distinct processes, while the serotonin neurons were ovoid shaped and lacked such processes. One week to 1 month after transplantation, the number of TH-positive fibers gradually increased, but their distribution was restricted to the area surrounding the cell bodies of the TH neurons in the graft. However, the processes of the serotonin neurons formed a dense plexus in the graft, and a small number of these fibers extended into the host iris 1 week after transplantation. By one month after the operation, the density of the serotonin fibers had gradually increased throughout the graft, and protruding serotonin fibers formed a network of varicose fibers in the host uveal tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Adjuvant chemotherapy for gastric cancer--the third study. First report: central randomization by telephone method and analysis of patients' background factors].

JFMTC conducted the third adjuvant chemotherapy study for gastric cancer patients after curative surgery from 1982 to 1983. Patients were randomly allocated to one of the three arms by telephone method controlled at the headquarters of the foundation. This method resulted in the marked reduction of ineligible cases (253 cases, 6.0% of 4,236 cases), compared with those in the first study (18.3%). Main reasons of ineligibility were the violation of entry criteria due to the misjudgment of noncancer, duplicate cancers and operative curability. Telephone method for random allocation seems to contribute to the improvement in the data quality of a clinical trial.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

[Multi-institutional cooperative study of adjuvant immunochemotherapy in gastric cancer--five-year survival rate].

The Gastric Cancer Immunochemotherapy Study Group, constituted of 412 institutions, carried out six independent trials simultaneously from 1978 to 1981. A total of 4,456 cases were subjected to the study, from which 826 cases (18.5%) were excluded due to the violence of entry criteria. Curative gastrectomy, followed by a combination of mitomycin C (MMC), Ftorafur (FT)and Krestin (PSK) produced better postoperative survivals than either combination of MMC and FT, or MMC and PSK (5-year survival rate: 71.7% in MMC + FT + PSK, 64.1% in MMC + PSK, and 58.5% in MMC + FT). In the subset of patients with negative nodes (n(-)), and with involved serosa by histological examination (ps(+)), a combination of FT and PSK after gastrectomy seemed to be more favorable for the post-operative survivals than the single use of either drug. Four drug combinations of MMC, FT, PSK and Picibanil (OK-432) also had a clinical benefit in the group of patients with poorly differentiated adenocarcinoma, compared with chemotherapy alone. These results, though there are biases due to excluding 18.5% of cases, suggest some clinical benefits in the control of cancer relapse after surgery. The conclusion should be confirmed by a further elaborate trial.

Adjuvants, Immunologic↗
PubMed1989

[A case of benign fibrous histiocytoma of the lung in a child].

A case of benign fibrous histiocytoma of the lung in a 8 years old boy was presented. He was first admitted in May, 1983, with recurrent pneumonia. Chest X-ray showed a ill-defined mass in the right lower lobe. Bronchoscopy revealed a round tumor, 1 cm. in maximum diameter, with complete obstruction of the Truncus Intermedius. Endoscopic resection was performed and partial obstruction of the Truncus Intermedius remained. He was re-admitted with pneumonia of the right middle lobe in March, 1986. Bronchoscopy showed severe stenosis of the Truncus Intermedius. Right middle and lower lobectomy was performed. The 4 X 4 X 3 cm tumor was located in the median of the Truncus Intermedius. Microscopically, the lesion composed of fibroblast-like cells and histiocyte-like cells. The patient's post-operative course was uneventful. He has no signs of local recurrence or metastasis. We believe, this is the first reported primary benign fibrous histiocytoma of the lung in a child in Japan.

Bronchial Neoplasms↗
PubMed1989

Cystadenoma and cystadenocarcinoma of the pancreas.

During the period 1963 to 1988, we treated 45 patients with cystic neoplasms of the pancreas. The patients were divided into group 1, which included 26 patients treated between 1963 and 1983, and group 2, which included 19 patients treated between 1984 and 1988. The rate of resection for cystadenoma was 67% for group 1 (n = 15) and 100% for group 2 (n = 11). The operative mortality rate was 0% for both groups. Pathologically, 17 patients (69%) had serous cystadenoma and nine (31%) mucinous adenoma. Except for 5 of the 15 patients from group 1 who died of other causes, all patients are healthy. The resection rate for cystadenocarcinoma was 36% for group 1 (n = 11) and 100% for group 2 (n = 8). In 2 patients from group 1 and 1 patient from group 2, the tumors had been diagnosed previously as benign by operative biopsy of the cyst wall. There was no operative mortality in either group. Cystic neoplasm was suspected from the results of ultrasonography and computed tomography in 70% of the patients in group 2. In 2 patients (25%), the preoperative diagnosis of pseudocyst associated with chronic pancreatitis was made. Adenocarcinoma was diagnosed in 3 patients by needle biopsy and cytologic examination of pancreatic juice. Eighty-two percent (9 patients) of group 1 died of recurrent carcinoma; 2 patients were alive without disease at 5 and 8 years. Thirty-eight percent (3 patients) of patients in group 2 died of recurrent carcinoma, two patients died of other causes, and 3 patients are still alive.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[The value and limitation of two-dimensional transesophageal echocardiography in diagnosis of dissecting aortic aneurysm].

The diagnostic value of two-dimensional transesophageal echocardiography (TEE) was evaluated in 29 patients with dissecting aortic aneurysm (DeBakey type I; 4, type II; 1, type IIIa; 6, type IIIb; 18) who were studied consecutively from May 1987 to August 1988. An intimal flap was demonstrated in all 29 cases. DeBakey type classification could be recognized in 26 of 29 patients (89.7%). The entry of aortic dissection could be identified in 26 of 29 patients (89.7%). The differentiation between true and false lumen could be performed in all 29 cases. The introduction of color Doppler and pulsed Doppler echocardiography has opened up an additional possibility, in particular an analysis of flow pattern of the lumen was valuable in differentiation between true and false lumen. TEE was also valuable in evaluation of operative procedure by means of intraoperative-TEE. The capability to visualize the lesion of descending aorta was superior to any other conventional diagnostic method such as CT, MRI, AOG. However, there were difficulties in scanning the distal part of the ascending aorta and aortic arch, and in identifying the reentry of arotic dissection except for DeBakey type IIIa dissection. Since transthoracic echocardiography was valuable in diagnosis of cardiac tamponade, aortic regurgitation, and DeBakey type I dissection, the diagnostic method of a combination of transthoracic and transesophageal echocardiography seems to be more valuable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗