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Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 523 records · Page 29Linked to original sources
PubMed1992

Stage I malignant lymphoma of Waldeyer's ring: frequent relapse after radiation therapy.

The natural history and therapeutic results of 26 patients with stage I malignant lymphoma of Waldeyer's ring (ML-WR) were analyzed retrospectively. Complete response was achieved in all 26. Relapse occurred in 9 of 21 (43%) patients treated with radiation therapy (RT) alone, while no relapse was seen in those treated with a combination chemotherapy consisting of cyclophosphamide, adriamycin, vincristine, and prednisolone (CHOP therapy). Relapse occurred within 1 year in 8 of the 9 patients. Relapse-free survival in the patients treated with RT alone was considered suboptimal.

Adult↗
PubMed1992

Heat-induced aggregation of recombinant erythropoietin in the intact and deglycosylated states as monitored by gel permeation chromatography combined with a low-angle laser light scattering technique.

Aggregate formation of recombinant human erythropoietin (r-EPO) on heat-treatment was followed by gel permeation chromatography combined with a low-angle laser light scattering technique under various conditions with respect to pH and salt concentration in order to provide basic knowledge about the change strictly required to be monitored for medicinal proteins. When heated at 60 degrees C at neutral pH, an aggregate with a limited size consisting of about 20 r-EPO molecules was formed. On heating at 50 degrees C at acidic pH, aggregation was unlimited. The aggregation proceeded non-covalently in acidic pH, but in alkaline pH covalent bond formation was also involved. Increase in salt concentration enhanced the aggregation. Deglycosylation of the N-linked oligosaccharides made r-EPO remarkably susceptible to aggregation on heat-treatment, indicating that the carbohydrate chains are essential to the stability of r-EPO.

Animals↗
PubMed1992

Prolonged QT interval in alcoholic autonomic nervous dysfunction.

QT prolongation on electrocardiography is related to sudden cardiac death and is frequently found in alcoholics. We studied QT prolongation in relation to the function of cardiac autonomic nerves assessed by the coefficient of variation of the R-R interval (CVRR) in three age-matched groups of men: 32 alcoholics with autonomic nervous dysfunction (AN), 32 alcoholics without AN, and 32 healthy controls. The QTc interval and CVRR were measured at rest on the 30th day of abstinence, when electrolyte imbalance had disappeared. Subjects with arrhythmia, conduction abnormality, cardiomegaly, ischemic heart disease or diabetes mellitus were excluded. A CVRR of less than 80% of standard predicted value was judged to represent AN. In alcoholics, QTc correlated negatively with the ratio of CVRR to its standard value (r = -0.49, p < 0.0001). The incidence of QTc prolongation was higher in alcoholics with AN (46.9%) than in alcoholics without AN (21.9%, p < 0.05). QTc prolongation was not observed in healthy controls. The QTc interval was significantly (p < 0.01) longer in alcoholics with AN (444 +/- 20 msec) than in alcoholics without AN (426 +/- 17) and in healthy controls (398 +/- 18). These results suggest that alcoholism causes dysfunction of the autonomic nerves as well as worsening QT prolongation, and this may predispose such patients to sudden cardiac death.

Adult↗
PubMed1992

Interdigestive gastric blood flow: the relation to motor and secretory activities in conscious dogs.

Blood flow in the left gastric artery was measured with an electromagnetic flowmeter in nine conscious beagle dogs. In the fasting state gastric motility and secretion exhibited periodical changes with an average cycle interval of 115.4 +/- 9.7 min. During a quiescent period, when gastric motility and secretion were minimal, the mean blood flow was stable at 33.9 +/- 3.8 ml/min. During the contracting phase each peristaltic contraction was coupled with a rapid fall and rise in blood flow (from 10.5 +/- 1.9 ml/min below to 21.2 +/- 3.8 ml/min above the precontraction levels) in 20-30 s. In addition there was a sustained elevation in blood flow (58.6 +/- 6.4 ml/min at the peak) lasting for 29.1 +/- 2.8 min. The onset of sustained blood flow elevation was preceded by that of motility in 63% of the cycles. In 23% of the cycles blood flow started to rise before the contracting phase began. Pepsin peaks coincided with blood flow peaks in two dogs and preceded the latter in the others. Feeding abolished periodic increases in motility and blood flow. It is concluded that left gastric arterial blood flow is not steady but exhibits dynamic changes in phase with periodic motor and secretory activities of the stomach in fasting conscious dogs.

Animals↗
PubMed1992

Complex formation of human T-cell leukemia virus type I p40tax transactivator with cellular polypeptides.

We examined cellular components which associate with p40tax, the viral transactivation molecule of human T-cell leukemia virus type I. Such molecules were searched by immunoprecipitation with polyclonal and monoclonal antibodies specific for p40tax. Two cellular proteins with molecular masses of 95 kDa (p95) and 60 kDa (p60) were specifically coprecipitated with p40tax from extracts of all p40tax-producing cell lines but not from p40tax-negative cell lines. The p60 component was also shown to associate with p40tax in vitro, by using radiolabel-chase experiments. Rabbit antisera specific for p60 and p95 were prepared by immunization with electrophoretically purified molecules. While anti-p95 antiserum coprecipitated p40tax, no p40tax could be identified in immunoprecipitates by using a polyclonal anti-p60 antiserum. The partial amino acid sequence of p60 demonstrated that p60 is identical to the human 60-kDa heat shock protein (a member of the chaperonin family of proteins). Although the biological significance of the complex formation of p40tax with p95 and p60 has yet to be determined, it may be that the complex formation is one of the mechanisms by which the biological activity of p40tax can be regulated.

Amino Acid Sequence↗
PubMed1992

Effects of mechanical vibration on left ventricular diastolic properties during global ischemia.

To examine the effect of mechanical vibration on ventricular relaxation and diastolic chamber stiffness under global ischemia, we studied eight coronary perfused, isolated, isovolumic canine left ventricles (LV). To produce varying degrees of impaired relaxation, graded coronary flow reduction and paced tachycardia were imposed. A mechanical 50-Hz, 2-mm-amplitude vibration was applied during diastole and was turned off during systole. Without diastolic vibration, the relaxation time constant of LV pressure (tau) increased with the severity of ischemia. The chamber stiffness index (K) from the diastolic pressure-volume relationship showed a slight increase during ischemia; tau decreased with diastolic vibration. The change in tau with vibration increased with ischemia and was dependent on vibration amplitude but not heart rate. The ratio of tau to the diastolic interval (DI, the time from peak negative rate of LV pressure change to end diastole) always decreased with vibration and was linearly correlated with K (r = 0.93; P less than 0.01). K decreased with vibration when tau/DI was greater than 0.3. We conclude that diastolic vibration improves impaired relaxation and chamber stiffness under myocardial ischemia.

Analysis of Variance↗
PubMed1992

Ultrastructural observation of calcification preceding new bone formation induced by demineralized bone matrix gelatin.

Demineralized bone matrix gelatin (BMG) was implanted into the skeletal muscle of Sprague-Dawley rats, and the resulting ultrastructural changes of the BMG were examined 3, 5, 7, 10, 15 and 20 days later. Most of the implanted BMG became calcified 7-20 days after implantation. Calcification ('acellular mineral deposition') was first observed as needle-shaped crystalline deposits in the BMG matrix on day 7 after implantation, which gradually increased in size and fused with one another in some deposits. They appeared to be divided into small partitions consisting of denatured collagen fibers unlike those of noncalcified BMG. Some deposits had electron-lucent areas in their center adjacent to well-calcified peripheral areas, and the central area contained many collagen-like fibers and spherical vacuoles. Osteoblast-like cells were not present around these calcified deposits 7 days after implantation. After that, new bone formation was often seen near the area of acellular mineral deposition, and the fused calcified deposits remained until day 15 after implantation. The noncalcified BMG was mainly absorbed by macrophages, and the sites of acellular mineral deposition were absorbed by multinucleated cells resembling osteoclasts which were considered to be activated by the implants. Acellular mineral deposition probably started as calcium and phosphate deposits on some materials in the BMG matrix, and by heterogenic nucleation without osteoblasts or matrix vesicles, inducing bone formation. Thus the BMG may be not only a carrier of bone morphogenetic protein, gradually supplying it to the surrounding tissue but also a storage site for minerals that are indispensable for bone formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1992

Appearance of adipose cells in connective tissue at the implantation site of bone matrix gelatin and bupivacaine injection.

Two types of adipose cells were found in the connective tissue on day 7 after bone matrix gelatin (BMG) implantation and an injection of bupivacaine: mature adipose cells with a large lipid droplet (2-140 microns) and immature adipose cells with many small lipid droplets (0.1-2 microns). On day 10 after BMG implantation, typical adipose tissue was observed near the implant. The immature adipose cells had small, spherical mitochondria, glycogen granules and cytoplasmic microvesicles, and they might differentiate from undifferentiated mesenchymal cells in the connective tissue or the peripheral cells around the vessels as a white adipose tissue. These findings suggest that the differentiation of adipose cells in the connective tissue near heterotopic bone formation might be induced not only by mechanical and/or bupivacaine injury, but also by some factor or factors of the BMG.

Adipocytes↗
PubMed1992

Diastolic vibration improves systolic function in cases of incomplete relaxation.

BACKGROUND: Incomplete relaxation of the left ventricle (LV) affects LV filling, but the subsequent effect on LV systolic function remains unclear. We attempted to improve relaxation by applying oscillatory mechanical perturbation during diastole (diastolic vibration) and examined the extent to which systolic function improved. METHODS AND RESULTS: Using 10 open-chest canine preparations, pacing tachycardia and administration of propranolol were imposed to induce various levels of incomplete relaxation. Myocardial length perturbation was induced with an oscillator attached to the LV surface (50 Hz, 1-mm amplitude) and was restricted to the period from the beginning of isovolumic relaxation to end diastole. At resting heart rates, diastolic vibration caused an immediate decrease in the time constant (T) of LV pressure fall without any influence on heart rate, LV peak systolic pressure (peak LVP), stroke volume (SV), LV peak positive dP/dt, and total systemic vascular resistance. With pacing tachycardia, diastolic vibration increased both peak LVP and SV at 160 beats per minute (before) and 120 beats per minute (after propranolol), simultaneously decreasing both T and LV diastolic pressures and increasing end-diastolic segment length. The increase in peak LVP and SV caused by diastolic vibration correlated with the T/diastolic interval (r = 0.82), the assumed index of severity of incomplete relaxation. CONCLUSIONS: These results suggest that diastolic vibration accelerates the LV relaxation rate and that this increased relaxation improves systolic function through the Frank-Starling mechanism.

Animals↗
PubMed1992

Intravascular ultrasound imaging--in vitro and vivo validation.

Intravascular ultrasound imaging is a new technique for visualizing arterial structures. The purpose of this study was twofold; first, to assess the ability of this intravascular ultrasound catheter to generate cross-sectional images of human artery segments in vitro and second, to determine the reliability of intravascular ultrasound technique in the evaluation of human arteries in vivo. For the vitro study, ultrasound images of the arteries were presented as a two-dimensional, 360 degrees display of vessel cross-section perpendicular to the long-axis of the probe. The ultrasound scanning provided an accurate description with high resolution of lumen structure and lumen-intima interface in all vessel specimens. There was a good correlation between the planimetric luminal area on the ultrasound images and the area obtained from histologic images (r = 0.92). There was also a good correlation in the plaque thickness between ultrasound and histological examination (r = 0.88). In the in vivo study, the ultrasound catheter was easily introduced, readily manipulated, and images were successfully obtained in all patients. No untoward effects were noted during manipulation of the catheter. There was a good correlation in the arterial dimension between ultrasound and angiographic measurements (r = 0.93). Thus, intravascular ultrasound imaging appears to be useful for characterizing and quantitating arterial lesions.

Carotid Arteries↗
PubMed1992

Ventricular contractility evaluated by mechanical perturbation of the myocardium--experimental and clinical approach adopting small amplitude vibration input.

Small amplitude mechanical vibration has been reported to depress the function of the isolated left ventricle in an amplitude dependent manner. We examined, 1) contractility and preload dependency of the magnitude of functional depression (VID) by applying 50 Hz, 2 mm amplitude vibration to the epicardium of the canine left ventricle and 2) whether VID is present in the failing human ventricle. The magnitude of VID was independent of preload in the physiological range of LV volume showing peak LV pressure greater than 75 mmHg, and VID was correlated with Emax at each inotropic state. In the in-situ condition, VID appeared only in the failing condition with a sensitive increase at a mild level of heart failure. In a study during routine cardiac catheterization (n = 27), the presence of VID has been demonstrated in the human ventricle (n = 18). The magnitude of VID was correlated with ejection fraction (EF) as, VID in peak LV pressure (mmHg) = 80.6 - 110 x EF, r = 0.84, p less than 0.01 in patients with EF less than or equal to 0.7 (n = 14). Therefore, we concluded that VID could be a clinical tool for evaluation of mild heart failure.

Animals↗
PubMed1992

Calcification preceding new bone formation induced by demineralized bone matrix gelatin.

Demineralized bone matrix gelatin (BMG) was implanted into the skeletal muscle of Sprague-Dawley (S.D.) rats, and histological changes were examined 3, 5, 7, 10 and 15 days later. Before bone formation, a specific calcification process was found in most of the BMG from day 5 and 7 after implantation. The heterotopic calcified sites were not always consistent with the sites of the alkaline phosphatase activity. It was considered that this calcification progresses without any cellular components, and we distinguished this type of calcification as "acellular mineral deposition" from the calcification which occurs in new bone formation. This "acellular mineral deposition" was first observed as small spherical calcified deposits in the BMG on day 7 after implantation; these deposits then gradually grew and fused with each other. Some multinucleated cells appeared near the site of calcification on day 7 after implantation, but osteoblasts or osteoblast-like cells were scarcely observed around the calcified deposits in BMG until day 7. Vascularization was often observed near the "acellular mineral deposition" and the new bone formation. Fourier transform infrared spectroscopy showed that the calcified deposits in BMG were composed of hydroxyapatite, carbonateapatite and other calcium phosphate components, and that the first two components became prominent with time. It is believed that the "acellular mineral deposition" is due to the deposition of calcium and phosphate into the BMG by a process of heterogenic nucleation that does not involve osteoblasts or matrix vesicles. Bone formation induced by the BMG occurred after the "acellular mineral deposition." The experimental calcification shown in this paper seems a useful model for the study of biocalcification.

Alkaline Phosphatase↗
PubMed1992

Anti-centromere antibody and CREST syndrome in patients with primary biliary cirrhosis.

Anti-centromere antibodies (ACA) in 41 sera from patients with primary biliary cirrhosis (PBC) were analyzed by an immunoblotting method and the correlation between the presence of ACA and the clinical features in these PBC patients was studied. In 10 of 16 ACA-positive PBC patients, one or more clinical features of CREST syndrome (PBC-CREST) were found. Statistical differences were observed in age at disease onset, serum levels of IgM and total bilirubin and titer of anti-M2 antibody, between PBC-CREST patients and the PBC patients without CREST symptoms (PBC-non CREST). By immunoblotting analysis, three major epitopes of ACA were identified at 18 kD, 80 kD and 140 kD polypeptides. The 18 kD polypeptides were detected in all 16 ACA-positive PBC patients. From these results, it is suggested that ACA-positive PBC-CREST patients can be separated from ACA-negative PBC-CREST and PBC-non CREST patients.

Adult↗
PubMed1992

[Effects of intra-arterial infusion chemotherapy with radiation therapy for advanced hepatocellular carcinoma].

Eight cases were treated with periodic arterial infusion therapy from reservoir and four cases with arterial infusion therapy plus 30 Gy's radiation therapy for hepatocellular carcinoma (HCC). The anatomical extent of the tumor was E3 and E4, respectively. We evaluated these forms of therapy from the viewpoint of tumor characteristics, survival time and therapeutic effects. There was no effective case of life prolongation and most of the reservoir only treated cases died a short time after therapy. But no severe complication was observed in reservoir plus radiation cases. One case showed a response, and another case tumor necrosis. The results indicate that this method is effective for advanced HCC.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

[THP-adriamycin-based combination chemotherapy in the treatment of non-Hodgkin's lymphoma].

Thirty patients with non-Hodgkin's lymphoma were treated with THP-adriamycin-based combination chemotherapy. Complete remission was obtained in eighteen (72%) of 25 evaluable patients. Nine of 18 patients are still alive in complete remission lasting 9 to 34 months (median 24 mo). Severe side effects such as bone marrow suppression, gastrointestinal symptoms and cardiotoxicity were rare. It was concluded that THP-adriamycin-based combination chemotherapy is relatively mild and safe, so this regimen is useful for elderly patients or patients with complications.

Adult↗