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Biomedical subjects

Y Higuchi

Publications and source records attributed to Y Higuchi.

At least 307 records · Page 17Linked to original sources

Lymphocyte chemotaxis in inflammation. III. Demonstration of lymphocyte chemotactic activity in extract from PPD-induced delayed hypersensitivity skin reaction site in the guinea-pig.

Various skin extracts from inflammatory lesions in guinea-pigs were assayed for chemotactic activity for guinea-pig lymphocytes; distinct chemotactic activity was shown in extract from PPD-induced delayed hypersensitivity reaction sites, and the time-course of chemotactic activity almost paralleled the intensity of lymphocyte reaction in skin sites. However, extracts obtained from various control sites or passive Arthus reaction sites exhibited little chemotactic activity for the cells. It is therefore suggested that lymphocyte chemotactic factor(s) was produced in the soluble form in the delayed hypersensitivity reaction.

Animals↗

The structure of cytochrome c3 from Desulfovibrio vulgaris Miyazaki at 2.5 A resolution.

The structure of tetraheme cytochrome c3 isolated from Desulfovibrio vulgaris Miyazaki has been determined at 2.5 A resolution by an X-ray diffraction method. Protein phases were computed by the multiple isomorphous replacement method using the native and four heavy atom derivatives, anomalous scattering measurements of the latter being considered. The mean figure of merit was 0.77. Four heme groups are exposed on the surface of the molecule. There are some short helical segments in the polypeptide chain, and hair-pin turns are often observed at glycine and alanine residues.

Amino Acid Sequence↗

On cytochrome c3 folding.

The structure of cytochrome c3 from Desulfovibrio vulgaris Miyazaki (DvM) is considered in detail by scrutinizing main chain folding together with the structure of the protein from D. desulfuricans Norway (DdN). The relative arrangement of the four heme groups in this molecule is similar to that of DdN and the disposition of alpha-carbon atoms of cysteine and histidine residues binding to heme groups is also similar. Structural differences between the two proteins occur in the shape of some specific loops of the chain on the molecular surface. As a result of a careful comparison of structures and sequences in both cytochromes c3, the reported sequence alignment of the cytochrome c3 family has been revised. Our new proposal of a sequence alignment based on the three-dimensional structures contains 24 evolutionarily conservative residues. All these conservative residues may play an important role in the folding pattern of cytochromes c3.

Amino Acid Sequence↗

Morphological observations of peripheral nerves by the scanning electron microscope.

In order to observe a normal peripheral nerve and a changed peripheral nerve by means of a scanning electron microscope, the present study was carried out. In the changed nerve fibers, they were enveloped by many processes of hypertrophied Schwann cells, and the processes of the Schwann cells seemed to make a pseudosyntitium-like structure with each other. From this finding, it was speculated that these Schwann cells seemed to follow the reverse process in the development of normal peripheral nerve fibers.

Animals↗

[Counterclockwise rotation of the heart: a correlative study with tomographic echocardiography].

On the long-axis view of tomographic echocardiography, the aorto-septal angle (AS angle) of cases with straight back syndrome was wide and was thought to be due to clockwise rotation of the heart rather than right ventricular enlargement. In the present study, the AS angle of 21 cases with counterclockwise rotation of the heart (CCW) was measured on the long-axis view. The counterclockwise rotation of the heart defined here as having a shift of the transitional zone to the right with a small septal q wave at V2 and/or V3 to V6 in the precordial leads. Every case of CCW was found to have an absence of main pulmonary artery shadow on posteroanterior projection of the chest X-ray film. The control groups consisted of 40 normal individuals and 14 cases of straight back syndrome. The AS angle of normals ranged from 120 degrees to 158 degrees with a mean of 142 degrees. The AS angle of the latter varied from 140 degrees to 165 degrees with a mean of 150 degrees. On the other hand, the 21 cases with CCW showed the AS angle from 80 degrees to 129 degrees with a mean of 102 degrees. Since every CCW showed dilatation and/or elongation of the thoracic aorta on their radiographs, the narrowed AS angle was probably due to rightward twist of left ventricular outflow tract with some posterior retraction of the aorta. This causes the rightward twist of upper portion of the septum and results in a shift of the transitional zone to the right with a small q wave at V2 and/or V3 to V6 in the precordial leads. When normally visible main pulmonary artery shadow disappears on the postero-anterior chest X-ray film, the CCW is indicated radiographically. The narrowing of the AS angles on the long-axis views of tomographic echocardiography also indicates the CCW and correlate with both electrocardiographic and radiographic findings of CCW. The cause of CCW has not been well delineated. In the previous paper, we have suggested that the left ventricular overloading has little influence in producing CCW. In the present study, the 21 cases with CCW did not show either the left ventricular hypertrophy or the dilatation on their echocardiograms further supporting our hypothesis.

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