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Biomedical subjects

A Kodama

Publications and source records attributed to A Kodama.

At least 91 records · Page 5Linked to original sources
PubMed1984

Studies on structure and function of rhodopsin by use of cyclopentatrienylidene 11-cis-locked-rhodopsin.

The photochemical reaction of cyclopentatrienylidene 11-cis-locked-rhodopsin derived from cyclopentatrienylidene 11-cis-locked-retinal and cattle opsin was spectrophotometrically studied. The difference absorption spectrum between the cyclopentatrienylidene 11-cis-locked-rhodopsin and its retinal oxime had its maximum at 495 nm (P-495). Irradiation of P-495 at -196 degrees C with either blue light or orange light caused no spectral change, supporting the cis-trans isomerization hypothesis for formation of bathorhodopsin. Upon irradiation of P-495 at 0 degree C with orange light, however, its absorption spectrum shifted to a shorter wavelength owing to formation of a hypsochromic product. The difference absorption spectrum between this product (P-466) and its retinal oxime showed its maximum at 466 nm. Analysis of retinal isomers by high-performance liquid chromatography showed that this spectral shift was not accompanied by photoisomerization of the chromophore. P-466 could almost completely be photoconverted to the original pigment (P-495) by irradiation at 0 degree C with blue light with little formation of the other isomeric form of its chromophore. The alpha-band of the circular dichroism spectrum of P-495 was very small in comparison with that of rhodopsin, while that of P-466 was comparable to it. These facts suggest that P-495 has a planar conformation in the side chain of the chromophore and that P-466 has a twisted one, probably at the C8-C9 single bond. Cyclic-GMP phosphodiesterase in frog rod outer segment was activated by neither P-495 nor P-466. This result suggests that the isomerization of the retinylidene chromophore of rhodopsin is indispensable in the phototransduction process.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1982

Severe middle ear anomaly with underdeveloped facial nerve. A temporal bone histopathologic case report.

The temporal bone histopathologic condition of a 9-year-old patient with unilateral congenital facial palsy and an auricular anomaly is described. The major pathologic findings were an extremely underdeveloped facial nerve, abnormal course of the facial nerve, an abnormally large middle ear artery that was suspected to be a persistent stapedial artery, absence of a pneumatized tympanic cavity, a severe ossicular anomaly, and an enlarged Eustachian tube. We believe that this child had a severe type of developmental anomaly of the middle ear, possibly caused by changes that occurred in early embryonal life. We reviewed the literature for similar cases in which the facial nerve is anomalous. We present a classification of such anomalies in the temporal bone in this case and in eight others and discuss the clinical implications of such anomalies.

Adolescent↗
PubMed1980

Early heart failure as a cause of growth and tissue disorders in children with congenital heart disease.

Height, weight, total body fat, lean body mass, size of fat cells and total number of lipid-containing fat cells were compared in two groups of children, ages 2-6 years, with congenital heart disease. Twelve children who developed heart failure in infancy made up one group and 14 asymptomatic patients made up the other. No patient was cyanotic or had undergone surgical repair. Patients with heart failure were shorter and lighter than asymptomatic patients. Whereas both fat and lean tissues were less in the heart failure group, reduction in body fat was more important in producing underweight. Although there was no difference in the size of fat cells, the number of lipid-laden fat cells was diminished in the children who had early heart failure. Thus hypocellularity of fat cells appeared to be the major determinant of diminished body fat with heart failure. Because shortness and decreased lean tissue were associated with these adipose tissue abnormalities, it is likely that widespread changes are caused by early heart failure. As previously reported with hypoxemia, the early development of heart failure seems to produce tissue changes that handicap growth.

Adipose Tissue↗
PubMed1979

Photochemical reaction of 9-cis-retro-gamma-rhodopsin at low temperatures.

9-cis-Retro-gamma-rhodopsin (lambda max = 420 nm) was prepared from 9-cis-retro-gamma-retinal and cattle opsin. After cooling to liquid nitrogen temperature (77 K), the pigment was irradiated with light at 380 nm. The spectrum shifted to the longer wavelengths, owing to formation of a batho product. This fact indicates that the conjugated double bond system from C-5 to C-8 of the chromophoric retinal in rhodopsin was not necessary for formation of bathorhodopsin. Reirradiation of the batho product with light at wavelengths longer than 520 nm yielded a mixture composed of presumably 9- or 11-cis forms of retro-gamma-rhodopsin. These three isomers are interconvertible by light at liquid nitrogen temperature. Thus the retro-gamma-rhodopsin system is similar in photochemical reaction at 77 K to cattle rhodopsin system. Each system has its own batho product. Based on these results, it was infered that the formation of batho-rhodopsin is due to photoisomerization of the chromophoric retinal of rhodopsin and is not due to translocation of a proton on the ring or on the side chain from C-6 to C-8 of the chromophoric retinal to the Schiff-base nitrogen.

Animals↗
PubMed1979

Nerve supply to the inner sensory cells in a human cochlea.

A choclear apical turn taken from a 66-year-old woman showed an area with marked decrease in number of the inner sensory cells. After observation by scanning electron microscope, the same specimen was thin-sectioned tangentially to the osseous spiral lamina. Numbers of myelinated nerve fibers were counted and the thickness of the fiber was measured by computed measuring equipment. Compared to the area with inner sensory cells intact, the area without inner sensory cells showed a 70% decrease in number of myelinated fibers. These degenerated fibers might have had intimate relationship with the inner sensory cells, probably being the afferent nerve supply to the inner sensory cells.

Aged↗
PubMed1979

Pores of the palatine tonsillar crypt and pharyngeal tonsillar recess--a scanning electron microscopic study--.

The crypt of the palatine tonsil and the recess of the human pharyngeal tonsil were studied using a scanning electron microscope. Many pores, ranging in diameter from 10 to 100 microns, were observed on the luminal surface of the crypts. All of the crypt surface except at the sites of pores was covered by epithelial cells. Non-epithelial round cells, mostly lymphocytes, were exposed directly to the crypt lumen through these pores. In the lumen of palatine tonsillar crypts, numerous round cells were present which evidently pass through these pores from the parenchyma. This finding indicates that the tonsillar parenchyma is directly open to the crypt. Similar findings were obtained in the recess of the pharyngeal tonsil.

Child↗
PubMed1978

Electrocyclization reaction of higher conjugated polyenals: photochemical behaviors of retinal (vitamin A1 aldehyde) homologues.

During the studies on a photoreaction of retinal, involving various kinds of (Z)-(E) isomerization, a heretofore unknown photoproduct of retinal was isolated in a pure state and was characterized unambiguously. Thus, direct irradiation of all-(E)-retinal (I) and of all-(E)-beta-ionylidenecrotonaldehyde (II) in acetonitrile solution gave the corresponding 6e-electrocyclized photoproducts, (III) and (IV), both via the possible 7-(Z)-isomer intermediates of the parent conjugated polyenals. Unlike the lower members in the retinal series, it was also confirmed that sigmatropic rearrangement or photo-Diels-Alder reaction hardly proceeds in these higher members of the series mentioned above.

Acetonitriles↗
PubMed1977

Simultaneous determination of cis-trans isomeric retinals by high-performance liquid chromatography.

A high-performance liquid chromatographic method for the simultaneous determination of geometric isomers of retinal in a mixture has been developed. The method can be applied to problems such as determination of optimal conditions for the preparation of a particular isomer, or the investigation of novel photoproducts from retinal. Aprotic solvent effects on cis-trans isomerization are discussed.

Chromatography, High Pressure Liquid↗