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H Miyazawa

Publications and source records attributed to H Miyazawa.

At least 145 records · Page 8Linked to original sources
PubMed1988

Small pustules in Kawasaki disease. A clinicopathological study of four patients.

We report the clinical and histological changes of small pustules that developed in four patients with Kawasaki disease (KD). The small pustules were superimposed on the urticarial erythema and symmetrically arranged on the genital area, buttocks, axillae, and extensor surface of the extremities. These lesions showed spongiform pustules histologically and were different from miliarial pustules. Reviewing previous reports, the clinical and histological characteristics of pustules in KD are summarized herein. This study indicates that small pustules underwent the consecutive changes related to the generalized polymorphous exanthem in KD.

Adult↗
PubMed1988

Glomerulonephropathy with amyloid-stain-negative microfibrillar glomerular deposits.

A 44-year-old man demonstrated proteinuria, microhematuria and renal dysfunction during the course of hyperthyroidism. Neither cryoglobulinemia nor paraproteinemia including light chains was found. No systemic signs suggestive of amyloidosis appeared. Histological findings showed a diffuse mesangial matrix increase with slight mesangial proliferation and diffuse granular depositions of IgG, IgA, C3, C4, Clq, kappa and lambda light chains. Ultrastructurally, microfibrils of about 20 nm in width were seen to be deposited diffusely in mesangial areas and in glomerular basement membranes. Congo red and thioflavin T staining were negative. These findings support the possible existence of a specific glomerular disease different from amyloidosis.

Adult↗
PubMed1987

Characterization of revertants derived from a mouse DNA temperature-sensitive mutant strain, tsFT20, which contains heat-labile DNA polymerase alpha activity.

One spontaneous and four N-methyl-N'-nitro-N-nitrosoguanidine-induced revertants of a mouse FM3A mutant, tsTF20, which has heat-labile DNA polymerase alpha activity and cannot grow at 39 degrees C, were isolated and characterized with respect to the thermolability of their DNA polymerase alpha activity, the intracellular level of enzyme activity, growth rate, cell cycle progression, and frequency of initiation of DNA replication at the origin of replicons. DNA polymerase alpha activity in the extracts from the revertant cells showed partial recovery of heat stability. The intracellular level of enzyme activity of the revertant cells was lower than that of wild-type cells even at 33 degrees C. The level of enzyme activity in the revertant cells decreased considerably after a temperature upshift to 39 degrees C, but the DNA synthesizing ability of these cells did not decrease as much as the level of enzyme activity. The growth rates of the wild-type and revertant lines were almost the same at 33 degrees C. At 39 degrees C, the rate for the wild-type increased considerably compared to that at 33 degrees C, while little difference in the growth rates of the revertant lines was observed at the two temperatures. Therefore, the doubling times of the revertant cells were relatively increased compared to those of wild-type cells cultured at the restrictive temperature. Flow microfluorometric analysis and cell cycle analysis to measure labeled mitosis revealed that the increase in the doubling time was due mainly to the increase in the duration of the S phase. Analysis of the center-to-center distance between replicons by DNA fiber autoradiography indicated that the frequency of replicon initiation per unit length DNA at a given time was reduced in the revertant cells growing at 39 degrees C.

Animals↗
PubMed1986

Identification of a DNA segment containing the human DNA polymerase alpha gene.

We isolated a temperature-sensitive mutant from mouse FM3A cells, designated as tsFT20, the DNA polymerase alpha activity of which is heat-labile. A hybrid clone (M6-39 cells) between human cells and tsFT20 cells contained one or two human chromosomes. M6-39 cells (primary hybrid) were exposed to gamma-ray and re-fused with tsFT20, after which we isolated two temperature-resistant secondary hybrids, both of which retained an identical minute portion of the human chromosome, 400-500 kilobase pairs (kbp). Immunological studies demonstrated that this secondary hybrid expressed human DNA polymerase alpha. Thus, the human DNA polymerase alpha gene was located within a DNA region of 400-500 kbp.

Animals↗
PubMed1986

Further characterization of a murine temperature-sensitive mutant, tsFT20 strain, containing heat-labile DNA polymerase alpha-activity.

tsFT20 cells, which have temperature-sensitive DNA polymerase alpha-activity, were characterized mainly at the cellular level. The cells lost their ability to synthesize DNA immediately after a shift to non-permissive temperature. The extent of decrease in the activity of DNA polymerase alpha in whole-cell extracts was the same as that of the decrease in the DNA replication ability determined by [3H]thymidine incorporation. At 39 degrees C, tsFT20 cells lost most of their colony-forming ability in one doubling time (16 h). The cells could not grow at higher than 38 degrees C, but could grow at 37 degrees C. When tsFT20 cells were synchronized at the G1/S boundary and incubated at 39 degrees C, they could not complete the S phase, ceasing cell cycle progression in mid-S phase. A temperature shift (33 degrees C----39 degrees C) experiment indicated that the whole S phase was temperature-sensitive, whereas the G2 and M phases were not. These results confirmed that DNA polymerase alpha plays a key role in DNA replication in mammalian cells.

Animals↗
PubMed1986

[Histochemical studies on skeletal muscle atrophy, with reference to the relationship between atrophy and muscle tension, and to the effect of electrical stimulation].

To clarify the significance of muscle tension and the effect of electrical stimulation on the immobilized muscle, two experiments were performed. First, the ankle joint of rat was fixed by a Kirschner-wire in two ways. After fixation at a strained position for one to twelve weeks, wet weight of soleus had decreased less than after fixation at a relaxed position. Histochemical investigation revealed the fiber type transformation of soleus from type 1 to type 2 at relaxed position, which was not observed at a strained position. The result confirmed the importance of muscle tension not only in the nutrition but also in the differentiation of the muscle. Secondly, electrical stimulation was given to the immobilized soleus for two weeks. Under the experimental procedure, the electrical stimulation prevented the transformation of muscle fiber type, but not muscle atrophy. This result suggested that the nutrition and the differentiation of muscle could be regulated independently.

Animals↗