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Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 703 records · Page 39Linked to original sources
PubMed1988

Subretinal precipitates of retinal detachments associated with intraocular tumors.

Yellowish white precipitates are sometimes observed clinically in the subretinal area of the retinal detachments. We investigated retinal detachments observed in a 47-year-old man associated with choroidal malignant melanoma and in a 1-year-old girl with retinoblastoma. Yellowish white precipitates were foam cells located around degenerated outer and inner segments of photoreceptor cells. They were more abundantly present associated with malignant melanoma than with retinoblastoma. They exhibited abundant lipid droplets, abundant lysosomes with phagocytosed materials including inner segments, fibrin, melanin and lipofuscin, abundant glycogen particles, indented nuclei, and cytoplasmic processes without intercellular junctional apparatus. They appeared to be macrophages.

Choroid Neoplasms↗
PubMed1988

Dependence of instantaneous transfer function on regional ischemic myocardial volume.

To obtain the instantaneous left ventricular transfer function curve (instantaneous TFC) under conditions of regional ischemia, sinusoidal accelerations ranging from 30 to 150 Hz were applied to a small area of the epicardium of cross-circulated isovolumic canine left ventricle, and the contralateral acceleration was measured under control and during regional coronary occlusion (n = 11). The TFC is the ratio of the output to input acceleration amplitudes. The instantaneous TFC was characterized as a single-peaked configuration under control coronary perfusion. However, TFCs progressively changed from a single-peaked to a double-peaked configuration during regional ischemia. To quantify this change in instantaneous TFC, we defined an index D as the mean squared difference of TFC during ischemia from TFC during control. Index D was linearly related to the percent mass of the ischemic region at 40 minutes after onset of ischemia. We conclude that 1) transfer function curves are sensitive measures of myocardial heterogeneity and 2) the fractional ischemic weight of the ventricle is a major factor in determination of the deformation in instantaneous TFC at the later stages of regional ischemia.

Animals↗
PubMed1988

The amino acid sequence, immunofluorescence and microinjection studies on the 15 kDa calcium-binding protein from sea urchin egg.

The 15 kDa protein is the most abundant low molecular weight Ca2+-binding protein, different from calmodulin, in eggs of sea urchin, Hemicentrotus pulcherrimus. The data from the amino acid sequence demonstrated that the 15 kDa protein belonged to the troponin C superfamily. Based on immunofluorescent and immunomicroscopic observations, we showed that the 15 kDa protein localized in the nuclei of fertilized eggs and mitotic apparatus of dividing eggs. Microinjection of the antibody against 15 kDa protein into sea urchin blastomeres resulted in the arresting of cell division. These results suggest that the 15 kDa protein plays an important role in mitosis of sea urchin egg.

Amino Acid Sequence↗
PubMed1988

Cardiovascular disease in the aged: overview of an autopsy series.

As an overview of cardiovascular disease in the aged, 3657 autopsy cases were analyzed for the frequency and age-wise incidence of cardiovascular disease. The three major categories, ischemic heart disease, valvular heart disease, and aortic aneurysm and dissection were described. 1. The incidence of overall cardiovascular disease increases sharply between the ages of 60 and 75. Prevention and treatment could be effectively directed at this age group. 2. The incidence of organic cardiovascular disease was: myocardial infarction 19.8 percent; valvular disease 10.0 percent; arteriosclerosis obliterans 3.5 percent; aortic aneurysm and dissection 3.3 percent; pericarditis 2.1 percent; cardiomyopathy 1.6 percent; cor pulmonale 1.4 percent; congenital heart disease 0.7 percent; and others 0.8 percent. 3. As coronary sclerosis progresses, death from ischemic heart disease increases; however, 7 out of 10 patients with 3 vessel disease still die of causes other than ischemic heart disease (pneumonia, malignancy etc.). The general management of infection and malignant neoplasms is important in addition to treatment of cardiovascular disease. 4. Except for mitral stenosis, valvular heart disease, the etiology of which is mostly non-rheumatic, increases with advancing age. 5. In aortic aneurysm, the rupture rate is relatively high in the thoracic aorta; however, this may be caused by the successful surgical repair of abdominal aneurysms. An aneurysm below 6 cm in diameter is not absolutely safe from rupture. 6. In aortic dissection, the interval from onset to the death of the patient is often too short to consider surgery.

Age Factors↗
PubMed1988

Anti-cancer therapy with valine-depleted amino acid imbalance solution.

For the purpose of developing amino acid imbalance solution applicable to cancer treatment, we prepared seven kinds of amino acid imbalance solutions based on a 10% balanced amino acid solution and investigated the anti-tumor effects of each solution. The administration of valine-depleted amino acid solution for 8 days at a daily dose of 53 ml/rat (79.5 kcal/rat) resulted in the most significant inhibitory effects on the growth of hepatoma (AH109A) and mammary tumors (MRMT-1), the rate being 82.8% and 90.8%, respectively. Side effects observed were inhibition of increases in host body weight, weight loss of the spleen and thymus, loss of hair, and a decrease in the amounts of total plasma protein and albumin. When the daily dosage of valine-depleted amino acid solution was reduced to 40 ml/rat (58.3 kcal/rat), anti-tumor effects were still noticed, while side effects were abated. These findings indicate that side effects accompanying the use of this solution can be alleviated by controlling the ingredients of the solution as well as the amount administered. It is thus suggested that valine-depleted amino acid imbalance solution is a valuable tool in the treatment of cancer.

Amino Acids↗
PubMed1988

The left ventricular vibration mode in the ventricular transfer function method and at the moment of the first heart sound.

Several investigators have aimed to clarify the patient's left ventricular (LV) physical properties by free vibration analysis of heart sound. Recently we have developed a transfer function (TF) method to calculate the LV viscoelasticity. To clarify whether this TF method and a clinical first heart sound (1 HS) analysis are based on the identical ventricular vibration mode analysis, we examined (1) the visualized LV vibration image in the TF method and (2) the quantitative relationship between the peak frequency of the 1 HS spectrum and that of TF curve in the early and late phase of the 1 HS. Isolated isovolumic potassium arrested canine left ventricles were used to visualize the vibration mode in describing the TF (N = 2). Examination of stroboscopically illuminated, slow-motion images revealed the oscillation of the ventricle to be of mode 2 behavior. To analyze the quantitative relation between the TF method and 1 HS analysis we used ten open-chest dogs. The correlation was good (r = 0.917) when the peak frequency of the TF curve at the early phase of the 1 HS was compared to the peak frequency of the 1 HS. We concluded that both the TF method and 1 HS analysis were based on the common, second-order ventricular vibration mode. Therefore, some information on the ventricular physical properties suggeted by the TF method could also be included in the clinical data obtained by 1 HS analysis.

Animals↗
PubMed1988

Molecular weight of tumor necrosis factor determined by gel permeation chromatography alone or in combination with low-angle laser light scattering.

The molecular weight of human recombinant tumor necrosis factor was determined at neutral pH by gel permeation chromatography alone or in combination with low-angle laser light scattering. Mean values of 39,200 +/- 800 and 48,800 +/- 900, respectively, were obtained by the two analyses. The results resolve the apparent discrepancy in the reported values of the molecular weight of this cytokine, confirming that it exists as a trimer in neutral solution with a molecular weight of about 50,000.

Chromatography, Gel↗
PubMed1987

Intracellular calcium concentration during pentylenetetrazol-induced bursting activity in snail neurons.

To clarify the role of intracellular free calcium in the provocation of bursting activity, the intracellular calcium concentration was measured using calcium-sensitive microelectrodes during pentylenetetrazol (PTZ)-induced bursting activity in snail neurons. In the PTZ-sensitive neurons of the snail, Euhadra peliomphala, the intracellular calcium concentration was higher than that in the normal state during PTZ-induced bursting activity, but lower than that which induced the calcium-activated potassium conductance elevation. By application of 50 microM calcium ionophore, A23187, a slight increase in intracellular calcium concentration with a slight depolarization occurred. Then a greater increase of intracellular calcium concentration with bursting activity was observed. By application of 100 microM A23187, a rapid and intense increase of intracellular calcium concentration with hyperpolarization was observed. These findings suggest that, for the provocation of bursting activity, sustained elevation of the intracellular calcium concentration, higher than that in the normal state but lower than that which evokes calcium-activated potassium conductance elevation, is required.

Action Potentials↗