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Biomedical subjects

T Tsuda

Publications and source records attributed to T Tsuda.

At least 469 records · Page 26Linked to original sources
PubMed1989

Establishment of an osteoinductive murine osteosarcoma clonal cell line showing osteoblastic phenotypic traits.

A clonal cell line, BFO-6, was established in culture from a Dunn osteosarcoma cell line (BFO) and characterized on the basis of bone-inducing activity, alkaline phosphatase activity, PTH sensitive cAMP production and tumorigenicity. Lyophilized pellets of devitalized cells, when implanted into the back muscles of allogenic host mice, consistently elicited heterotopic bone formation at 3 weeks postimplantation. BFO-6 cells were found to be rich in alkaline phosphatase activity and showed a significant response to h-PTH stimulation. The doubling time in the logarithmic phase was 17.2 h and the cells revealed an acrocentric karyotype. Subcutaneous transplantation of cells (1 x 10(7) cells) into a C3H mouse resulted in the production of a tumor with histological features of osteosarcoma. This tumor also retained bone-inducing activity and high alkaline phosphatase activity.

Alkaline Phosphatase↗
PubMed1989

Inhibitory effects of tumor necrosis factor alpha on fracture healing in rats.

Fracture healing, which involves a cascade of biological tissue responses, may be affected by various biochemical substances. One of these substances is tumor necrosis factor alpha (TNF). Studies were made on the effects of TNF on healing of fractured ribs of rats. Fracture healing was inhibited by daily administration of recombinant human TNF (400 micrograms/kg body weight per day, intraperitoneally) after fracture. The rate of union on day 20 was significantly lower in the TNF-treated group (4/18, 22.2%) than in the control group (14/18, 77.8%) (p less than 0.001 by Chi-square test). Histological examination showed that TNF inhibited cartilagenous callus formation. On day 10, cartilage was seen in the gap zone and under the periosteum in the control group, but no cartilage formation was observed in the gap zone in 9 of 12 specimens from the TNF-treated group. On day 20, the fracture ends were united by newly formed bone in the control group, but mature fibrous tissue was seen in the gap zone, and bony or cartilagenous union was not achieved in the TNF-treated group. These results show that TNF inhibits cartilage formation in the early phase of bone induction in fracture healing and suggest that this effect of TNF is due to its inhibition of differentiation of mesenchymal cells into chondroblasts.

Animals↗
PubMed1989

Angiotensin II stimulation of vascular smooth muscle cells. Secondary signalling mechanisms.

Activation of vascular smooth muscle by angiotensin II results in the phospholipase C-mediated generation of two second messengers, inositol trisphosphate (IP3) and diacylglycerol (DG). IP3 is responsible for mobilizing calcium from endoplasmic reticulum whereas DG activates protein kinase C and ultimately Na+/H+ exchange, leading to intracellular alkalinization. The IP3/calcium signal is transient, most likely serving to initiate calcium-mediated events leading to contraction, and is attenuated by activation of protein kinase C. DG formation/protein kinase C activation is sustained and may be enhanced by the concurrent intracellular alkalinization. The delay in induction of the sustained response appears to be related to cellular processing of the angiotensin II-receptor complex. Phospholipase C activity is also modulated by a cholera toxin-sensitive, pertussis toxin-insensitive guanine nucleotide regulatory protein. This guanine nucleotide regulatory protein, movement of the receptor-ligand complex, and the signals generated by the two second messengers, IP3 and DG, interact in a complex manner to cause an integrated response of vascular smooth muscle to angiotensin II stimulation.

Angiotensin II↗
PubMed1989

Coexpression of platelet-derived growth factor (PDGF) A-chain and PDGF receptor genes in human gastric carcinomas.

In this study we examined the expression of platelet-derived growth factor (PDGF) A-chain and PDGF receptor genes in seven human gastric carcinoma cell lines and 15 gastric carcinoma tissues. Expression of mRNA for PDGF A-chain was found in all gastric cell lines and all gastric carcinoma tissues. Two of the seven gastric carcinoma cell lines expressed PDGF receptor mRNA. Out of the 15 gastric carcinoma tissues, eight showed enhanced expression of PDGF receptor mRNA and all of them demonstrated prominent fibrous stroma. Moreover, the incidence of enhanced expression of PDGF receptor mRNA was higher in scirrhous carcinoma than in well differentiated adenocarcinoma. These results strongly suggest that PDGF produced by tumor cells acts as a paracrine growth factor for production of fibrous stroma in gastric carcinomas.

Adult↗
PubMed1989

Angiotensin II-stimulated protein synthesis in cultured vascular smooth muscle cells.

To investigate the role of vasoconstrictor hormones in vascular smooth muscle cell growth we have studied the effects of the potent vasoconstrictor angiotensin II on cell growth in a cultured rat aortic cell model. Angiotensin II was not mitogenic for these cells, as assessed by determining cell number, nor was it synergistic in this regard with 10% calf serum. However, 24-hour exposure to 100 nM angiotensin II caused an 80% increase in protein synthesis (compared with 0.4% increase with serum control) as measured by tritiated leucine incorporation. This was a "hypertrophic" response as indicated by a 30% increase in protein content and a 45% increase in cell volume. Angiotensin II-induced smooth muscle cell hypertrophy was maximal at 100 nM, had an ED50 of 1 nM, and was inhibited by the competitive antagonist [Sar1, Ile8]angiotensin II. The increase in protein synthesis required continuous presence of angiotensin II for 6 hours and required messenger RNA (mRNA) synthesis as suggested by complete inhibition after exposure to actinomycin D. Angiotensin II-stimulated protein synthesis was dependent on a rise in intracellular Ca2+ concentration evidenced by a 70% decrease in tritiated leucine incorporation after chelation of Ca2+ with 25 microM quin 2-AM. This treatment did not alter protein synthesis induced by 10% calf serum. Decreasing extracellular Na+ to prevent Na+/H+ exchange and intracellular alkalinization did not inhibit the angiotensin II response but decreased the 10% calf serum-stimulated protein synthesis by 35%. Downregulation of protein kinase C by 24-hour treatment with phorbol 12,13-dibutyrate did not inhibit angiotensin II-induced protein synthesis, while phorbol 12-myristate 13-acetate-stimulated protein synthesis was abolished. These findings suggest that angiotensin II-induced hypertrophy, acting via a Ca2+ mechanism, may play an important role in abnormal vascular smooth muscle cell growth in certain forms of hypertension.

Angiotensin II↗
PubMed1989

Experimental encephalomyocarditis virus infection in Mongolian gerbils (Meriones unguiculatus).

Two strains of Mongolian gerbils (Meriones unguiculatus), Tumble Brook (TUM) and Japan Medical Science (JMS), were intraperitoneally inoculated with the D variant of encephalomyocarditis virus (EMC-D) and killed 3 days later. Mortality was significantly higher in females than in males. Evidence of viral replication was detected in the heart of both strains and in the pancreas of the TUM strain. Histopathological alterations were found in the heart and pancreas. Heart lesions involved foci of necrosis with inflammatory cell infiltration and calcification in both strains. Pancreatic lesions were restricted to the exocrine glands; islets of Langerhans were rarely and secondarily involved in the extensive destruction of exocrine glands. Severe acinar cell necrosis with marked inflammatory edema was conspicuous in TUM, whereas only slight acinar cell involvement was detected in JMS gerbils. Immunoperoxidase staining showed viral antigens in intracytoplasmic vacuoles in damaged acinar cells.

Animals↗
PubMed1989

Presence and activity of alkaline phosphatase in two human osteosarcoma cell lines.

The presence and activity of alkaline phosphatase in SAOS-2 and TE-85 human osteosarcoma cells grown in culture were examined at the ultrastructural level. A monoclonal antibody raised against purified human bone osteosarcoma alkaline phosphatase was used to localize the enzyme in cultures of the osteosarcoma cells. Similar cultures were analyzed for alkaline phosphatase activity using an enzyme cytochemical method with cerium as the capture agent. Alkaline phosphatase was immunolocalized at the light microscopic level in an osteogenic sarcoma and ultrastructurally on the SAOS-2 cell membrane and the enclosing membrane of extracellular vesicular structures close to the cells. In contrast, the TE-85 cells were characterized by the absence of all but a few traces of immunolabeling at the cell surface. Enzyme cytochemical studies revealed strong alkaline phosphatase activity on the outer surface of the SAOS-2 cell membrane. Much lower enzyme activity was observed in the TE-85 cells. The results support biochemical data from previous studies and confirm that SAOS-2 cells have a significantly greater concentration of alkaline phosphatase at the plasma membrane.

3,3'-Diaminobenzidine↗
PubMed1989

Angiotensin II stimulation of vascular smooth muscle.

Angiotensin II (Ang II) stimulation of vascular smooth muscle results in a myriad of intracellular signals that interact to produce the final physiologic response of the cell. One of the earliest documented events following incubation of these cells with Ang II is the rapid, phospholipase C-mediated hydrolysis of phosphatidylinositol-4,5-bisphosphate to yield two second messengers, inositol trisphosphate and diacylglycerol. Inositol trisphosphate releases calcium from nonmitochondrial intracellular storage sites, while diacylglycerol activates protein kinase C. Ang II also stimulates calcium influx and increases calcium efflux for the duration of the stimulus, as well as causing a biphasic change in intracellular pH. The delayed alkalinization is a consequence of enhanced Na+/H+ exchange. These signals then interact to modify the targets of phospholipase C, and result in phosphorylation of numerous cytoplasmic and cytoskeletal proteins. Thus, the signaling events induced by Ang II are complex, and dynamically interact to produce a constantly changing response for the duration of the stimulus.

Angiotensin II↗
PubMed1989

Establishment of a cell line producing bone morphogenetic protein from a human osteosarcoma.

A human osteosarcoma cell line was established from a biopsy specimen from a 13-year-old girl. The osteosarcoma tissue was maintained in athymic nude mice (Balb C nu/nu) by serial transplantation for three years. The tumor was excised from a host mouse and digested with collagenase. The isolated cells were cultured by 98 passages in 14 months, and clones of osteosarcoma cells were obtained by limiting dilution. A clone named human osteosarcoma cell 6 (H-OS-6) that showed the osteoblastic phenotypes of productions of bone morphogenetic protein (BMP) and alkaline phosphatase and a response to human parathyroid hormone (h-PTH 1-34) was selected. The morphology of its chromosomes indicated its human origin. This human osteosarcoma cell line is unique in producing BMP under in vitro conditions.

Adolescent↗
PubMed1989

[DNA analysis for the kininogen gene of patients with kininogen deficiency in Japan].

The kininogen (KGN) gene status was examined in 4 families with both high molecular weight (HMW) and low molecular weight (LMW) KGM deficiency and one family with only HMW-KGN deficiency reported in Japan. No abnormal HMW-KGN or LMW-KGN was detected in those with these deficiencies by immunoblot analysis using monoclonal antibodies (HKG-H12, HKG-L7, HKG-L17) for human HMW-KGN. HMW-DNA prepared from peripheral blood leucocytes was digested with endonuclease, EcoRI, Bam HI, Hind III, Sca I, Bg1II, Xba I, Msp I, Pst I, Hpa I, PvuII, HaeIII, Rsa I, Alu I, or Taq I, and studied by Southern blot analysis with human LMW prekininogen cDNA (phKG 36) as a probe. A gross deletion or insertion of the KGN gene was not detected in those with both HMW- and LMW-KGN deficiencies. On the other hand, partial defect in intron 7 (G) was found in those with only HMW-KGN deficiency, suggesting that this defect might be related to abnormality of the alternative RNA splicing events for HMW-prekininogen mRNA.

DNA Probes↗
PubMed1989

[DDAVP administration in a case of congenital combined factor V and factor VIII deficiency].

Combined deficiency of factor V and factor VIII, a rare bleeding disorder, was found in a 43 year-old male. He had often presented manifestations of easy bruising since childhood, but none of his family had shown evidence of a bleeding tendency. We examined him and his family as far as we could and his abnormality of blood coagulation was apparent, but the members of his family were normal. The prothrombin time and activated partial thromboplastin time of this patient were prolonged, but his thrombin time was normal. Factor V and factor VIII coagulant activity were low, but von Willebrand factor antigen and activity (ristocetin cofactor activity) levels were normal. Protein C and Protein C inhibitor antigen and activity levels were also found to be normal. Following 1-deamino-8-D-arginine vasopressin (DDAVP) injection, he had immediate increases in factor VIII coagulant activity, but both von Willebrand factor antigen, activity levels and factor V coagulant activity remained low. Moreover, there was no rapid decline in factor VIII complex activity. These findings suggest that the endogenous factor VIII in this patient is metabolized normally and that at least the deficiency of factor VIII does not result from accelerated degradation in plasma.

Adult↗
PubMed1989

[Diagnostic 99mTc-labeled red blood cells scintigraphy in gastrointestinal tract bleeding from an intestinal pyogenic granuloma].

99mTc-labeled red blood cells (RBCs) scintigraphy was useful to detect the site of gastrointestinal (GI) tract bleeding in a 30-year-old woman. Other examinations, double-contrast barium meal study, fiberscopy and conventional contrast arteriography were unsuccessful in diagnosis. A surgical treatment was performed and GI tract bleeding from ileal pyogenic granuloma was proved. In this case the patient had no other obvious hemangioma or pyogenic granuloma. Pyogenic granuloma occurs most commonly on the exposed skin areas and very rare on the intestine.

Adult↗
PubMed1989

[A case of remarkable bronchial stenosis due to aspiration of delayed-release iron tablet].

This report describes a rare case of bronchial mucosal injury caused by aspiration of a delayed-iron tablet. A 44-year-old woman had been taking delayed-iron tablets (Feto-Gradumet) regularly because of iron deficiency anemia, and accidentally aspirated a tablet into her bronchus. After this accident, she had complained of wheezing and shortness of breath. On bronchoscopy, the bronchial mucosa of left lower lobe initially showed remarkable swelling and redness, and became corroded and narrowed gradually by iron toxicity over several months, although we tried to remove some fragments of tablet as completely as possible. While we had examined her bronchi repeatedly by bronchoscopy, the bronchial mucosa gradually normalized during 15 months, but moderate stenosis of the left basal bronchus remained. The pathological findings showed infiltration of inflammatory cells, edema and granuloma formation in the submucosal region. This report suggests that the bronchial injury was due to the toxicity of persistent ferrous sulfate eluted from the iron tablet which had adhered firmly to the wet bronchial wall for a long time.

Adult↗
PubMed1989

[Cardiac involvement of alcoholics and the effect of total abstinence].

Echocardiographic features of 221 alcoholics after total abstinence were investigated. At the time of admission, none demonstrated left ventricular (LV) enlargement. Noticeably, 26% patients out of the total showed LV wall thickening more than 1.4 cm in the interventricular septum. On the other hand, 19% of the alcoholics illustrated hypokinetic LV wall without chamber dilatation which was either less than 55% in ejection fraction or 30% in fractional shortening. Three months later, the LV wall thickness reduced significantly from 1.6 to 1.4 cm in average and the LV wall motion improved significantly from 27 to 31% in fractional shortening. In the cases with wall thickening, the change was well correlated with a decrease both in heart rate and in LV muscle volume, but not with a decrease in systemic blood pressure. No significant correlated factors could be detected in the hypokinetic cases.

Adult↗
PubMed1989

Rapid development of renal lesions in diabetic DBA mice infected with the D-variant of encephalomyocarditis virus (EMC-D).

Marked hyperglycaemia and renal lesions developed rapidly in DBA mice infected with 10 plaque-forming units of the D-variant of encephalomyocarditis virus (EMC-D). Renal alterations were demonstrated in the glomeruli, tubular epithelium and small vessels 2 months after infection. Glomerular changes were characterized by mesangial thickening due to an increase of basement membrane-like material in the mesangial matrix. Nodular glomerular lesions were commonly observed 3 months after infection, whereas distinct thickening of the glomerular basement membrane was rarely seen. Besides these glomerular changes, glycogen inclusions in the distal tubular epithelium and medial degeneration in the arterioles were also noticed. The EMC-D-infected DBA mouse appears to be a useful experimental model for the study of human diabetic nephropathy.

Animals↗
PubMed1989

[Pulmonary nodule confirmed by rib consolidation on thoracic computed tomography].

Coin lesions in the thoracic cavity, skin, muscle and connective tissue are clearly observed by computed tomography (CT). However, it is very difficult to detect abnormal shadows in the ribs by thoracic CT at the mediastinal level. We describe 3 cases of pulmonary nodules that were not detected by CT at the mediastinal or lung field level, however, but could be detected at the bone level. When pulmonary nodules cannot be detected by thoracic CT at the mediastinal or lung field level, it is recommended to change the window to the bone level.

Adult↗
PubMed1989

[Evaluation of left ventricular function in the patients with aortic regurgitation following aortic valve replacement by radionuclide cardiography].

Twenty patients undergoing AVR were subjected to this study and divided into the early and the late groups. 6 healthy adults were dealt as the control group. The EF, PER, 1/3 EF, TPE were compared among these three groups both at rest and during exercise. The detailed responses to the exercise were measured by %delta between at rest and during exercise. Furthermore, the LV function in the filling period were examined by the 1/3 FF and RFR at rest. This study suggests that although the left ventricular function and contractile reserve to the exercise remained insufficient in the early postoperative phase, nearly complete recovery of the reserve could be obtained in the later phase, while the left ventricular function in the rapid filling period was significantly decreased in both early and late postoperative phase.

Adolescent↗