Biomedical subjects

M Fukuda

Publications and source records attributed to M Fukuda.

At least 1,423 records · Page 79Linked to original sources

PubMed1978

Kinetics of biphasic reconstitution of tobacco mosaic virus in vitro.

The kinetics of the in vitro reconstitution of tobacco mosaic virus from its RNA and protein were studied by measuring the increase in turbidity, the development of ribonuclease-resistant infectivity, the emcapsidation of the terminal ends of the RNA, and the growth of rod length. The results showed that the reconstitution reaction consists of two processes in which the direction, timing, and rate of assembly are different. Rapid elongation of particles toward the 5' end of the RNA proceeds in the first 5-7 min to give intermediate particles of 260 nm in length in which only the 5' terminus of the RNA is encapsidated. The subsequent process requires 30-50 min, is accompanied by a slow increase in turbidity, and gives rise to rods of the full length, 300 nm. The 3' terminus becomes RNase resistant by this process with concomitant development of ribonuclease-resistant infectivity, showing that the 3'-distal portion of the RNA is encapsidated in the direction of 5' to 3'. The rate of rod elongation by the second process is less than 1/10 of that by the first process.

Capsid↗

PubMed1978

Preferential association of newly synthesized H3 and H4 histones with newly replicated DNA.

The assembly of newly synthesized histones into chromatin during replication of MH-134SC cells was studied. Cells pulse-labeled with iododeoxyuridine and [3H]lysine were mixed with an equivalent number of normal cells labeled with [14C]lysine. Nuclease chromatin obtained from pooled cells was fractionated by buoyant-density centrifugation in a gradient containing Metrizamide and 3-iodo-1,2-propanediol. Histones extracted from heavy and normal chromatin regions of the gradient were fractionated by acid-urea gel electrophoresis, and 3H/14C ratios of individual histones were compared. The results showed highly preferential association of newly synthesized H3 and H4 with newly replicated DNA.

Cell Line↗

PubMed1978

Changes in cell population kinetics during epidermal carcinogenesis.

The changes in cell population kinetics in response to a mechanical stimulation by wounding were studied in a hyperplastic epidermis, papilloma and a squamous cell carcinoma of the mouse dorsal skin induced by repeated treatments with 20-methylcholanthrene. The G0 cell population, which consists of about 66% of the basal cells in the dorsal epidermis of the normal mouse, disappeared in hyperplastic epidermis, papilloma and carcinoma. The zone of proliferating cells enlarged in the papilloma, including several supra-basal layers, in contrast to its strict localization in the basal layer in hyperplastic epidermis. Proliferating cells were distributed in almost all areas in the carcinoma without localization. The normal responses to wounding were preserved in the hyperplastic epidermis, except for the absence of G0 cells, while the papilloma and carcinoma showed no increase in proliferating cells or shortening of the cell cycle time. From the view-point of cell population kinetics, papilloma and carcinoma are regarded as the tissues in which the flexible control mechanisms of irreversible cell differentiation to mature cells and of the length of cell cycle time are lacking.

Animals↗

PubMed1978

Chondroectodermal dysplasia (Ellis--van Creveld syndrome) with dysplasia of renal medulla and bile ducts.

A case of a 28-month-old boy with chondroectodermal dysplasia (Ellis-van Creveld syndrome) is reported. Besides polydactyly, ectodermal dysplasia, acromelic dwarfism and congenital heart defect, which are characteristic morphologic features of the syndrome, additional dysplastic developmental defects were discovered in the kidneys, liver, and lungs. Detailed histopathologic studies of the growth plates of tibia, femur and ribs disclosed an irregular, partly hyperplastic, partly dystrophic appearance of the epiphyseal cartilage, which was not resorbed properly by the invading blood vessels. Focal areas of necrosis occurred and barriers of tongue-shaped cartilaginous peninsulas persisted. Regular enchondral ossification was hindered and compensatory membrane ossification was found in the fibrosing metaphyseal bone marrow adjacent to the cartilage. Dysplasia and fibrosis of the renal medulla plus interstitial fibrosing nephritis in the cortex resulted in kidney contraction and renal failure. Hepatomegaly, portal fibrosis and bile duct hyperplasia and dysplasia were detected at autopsy, but did not have any clinical significance. These findings once again emphasize that derivatives of all three germ layers are involved in the Ellis-van Creveld syndrome. The possibility that a single metabolic or structural abnormality of the mesenchymal tissues could be responsible for the various organ dysplasias is discussed.

Bile Ducts↗

PubMed1978

Annulate lamellae in erythroblasts in the mice splenic colonies.

Lethally irradiated mice received a transfusion of normal bone marrow cells from the same strain mice. The transfused colony-forming cells (stem cells) were settled in the spleen of the recipient and proliferated in it into erythroblast colonies. Some of these mice were given chloramphenicol or thiamphenicol for 7 days after marrow cell transfusion. Annulate lamellae were frequently observed exclusively in the erythroblasts of the mice received a injection of thiamphenicol.

Animals↗

PubMed1978

Diagnosis of persistent truncus arteriosus by two-dimensional echocardiography: a case study.

Two-dimensional echocardiography of a patient revealed overriding of the large aortic trunk which bifurcated above the semilunar valve, suggesting persistent truncus arterious. This diagnosis was confirmed by cardiac catheterization and angiocardiography. Surgery and autopsy also confirmed the accuracy of the two dimensional echocardiographic findings. Two-dimensional echocardiography is thus valuable in diagnosing persistent truncus arteriosus.

Angiocardiography↗

PubMed1978

Enflurane-induced hypotension modifies transmural blood flow distribution in the canine left ventricle.

Coronary and systemic circulations, and contractility and oxygen consumption of the left ventricular myocardium were depressed as arterial enflurane concentration increased in acute experiments with 22 adult mongrel dogs. Uneven transmural blood flow in the left ventricular free wall did not appear and the inner/outer ratio remained near 1.0 until a very deep stage of the anesthesia was attained and as far as diastolic aortic pressure was maintained above 40 mmHg, according to the microsphere injection study. Once diastolic pressure fell below 35--40 mmHg, the ratios started to be reduced significantly. When arterial enflurane content reached 53.0 +/- 2.1 mg/100 ml (mean +/- s.e.), the ratio became 0.84 +/- 0.08 (p less than 0.001), and simultaneously calculated DPTI/TTI ratio also showed a significant redution from the control (0.79 +/- 0.03, p less than 0.001). The I/O and DPTI/TTI ratios, however, did not correlate significantly with each other until very deep enflurane anesthesia was attained. The lower limit of autoregulation of coronary vascular bed was suggested to be near 35--40 mmHg of diastolic aortic pressure during deep enflurane anesthesia in the dog. Among systolic time intervals measured directly during the study, PEP and ICT showed significant negative correlations with Vmax and LV dp/dt max, while LVET neither changed nor correlated significantly with stroke volume or other parameters representing myocardial contractility during the course of enflurane anesthesia.

Animals↗

PubMed1978