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Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 523 records · Page 29Linked to original sources
PubMed1976

Polarographic studies in presence of Triton X-100 on oxidation-reduction components bound with chromatophores from Rhodospirillum rubrum.

Polarographic studies on oxidation-reduction components bound with chromatophores from Rhodospirillum rubrum were carried out at 24 degrees. 1. Using a carbon-paste electrode as the working electrode, polarographic waves characteristic of oxidation-reduction components were observed in the presence, but not in the absence of Triton X-100; these waves were therefore measured in the presence of the detergent. 2. At least two kinds of oxidation-reduction components were detectable, having different half-wave potentials (E1/2); at pH 7, one had an E1/2 value of +275 mV (POC+275) and the other had a value of +60 mV (POC+60). 3. POC+275 was reduced by succinate and by NADH. Both reductions were almost completely inhibited by antimycin A, which hardly affected the reductions of ubiquinone-10 by succinate and by NADH. Most POC+275 molecules were not reduced by the substrates when quinones were extracted from the chromatophores, and the reductions were mostly restored when ubiquinone-10 was re-added. This indicates that POC+275 is functional between ubiquinone-10 and cytochrome c2 in the electron transport system. 4. POC+60 was reduced by succinate, but hardly at all by NADH. The reduction of POC+60 was not influenced either by the addition of antimycin A or by the extraction of quinones. This suggests that POC+60 is functional in the process from succinate dehydrogenase [EC 1.3.99.1] to ubiquinone-10 in the electron transport system. 5. Of the POC+275 reducible by dithionite, approximately 70% could be reduced in the absence of Triton X-100, provided that the potential of the working electrode immersed in chromatophore suspensions was set at potentials of 0 mV or lower and that the electrochemical reaction was carried out at pH 7.5. When the potential of the electrode was set at +50 mV (the same as the E1/2 value of ubiquinone-10 bound with chromatophores), and the suspension was allowed to stand for various lengths in the presence of the detergent, it was found that approximately half of the electrochemically reducible POC+275 was rapidly reduced, followed by a slow reduction. The discrepancy in the oxidation-reduction equilibrium on the basis of the E1/2 values of ubiquinone-10 and POC+275 is discussed.

Antimycin A↗
PubMed1976

[Peripheral arterial aneurysm of the brain occurring after brain abscess extirpation and healing spontaneously-report of a case and review of the literature (author's transl)].

In 33 year-old man an aneurysm of a pheripheral branch of the right middle cerebral artery was disclosed by angiography 8 days after extirpation of a parietotemporal brain abscess. The aneurysm was absent in the preoperative angiogram. Since the site of the aneutysm coincided with the operative field, it is sure that the etiology of the aneurysm was related to operative trauma and/or arteritis. Although inflammatory or mycotic factor could not be excluded from its etiology, it seems reasonable that traumatic factor was major one. The aneurysm was found to have disappeared eventually in the angiogram made on 372th postoperative day. Traumatic aneurysms arising from peripheral branches of the intracranial arteries are very rare. The first case was reported by Krauland in 1949. We collected 32 such cases from the literature. Of the 33 cases including the present one, 5 are iatrogenic. In more than half of the 33 cases, aneurysms were formed within 14 days following head injury. Posttraumatic delayed hemorrhage was found in 15 cases, the hemorrhage occurring within one month following injury in 12 cases. Of 31 cases with known prognosis, 11 died, 6 of them dying of delayed hemorrhage. Aneurysm operation was performed in 21 cases and 15 of them survived. In the present case, aneurysm luckily healed spontaneously. There are two cases including the present one, of spontaneous healing in the 33 cases. We believe surgical treatment is one of choice whenever possible.

Adult↗
PubMed1975

Extraneural metastasis of pineal tumor.

The case of an eight-year old male with a pineal tumor is reported, in which metastases occurred to extraneural organs. The pineal tumor consisted of portions of benign teratoma, malignant ependymoma and embryonal carcinoma. Only the embryonal carcinoma metastasized. The intracanial and spinal subarachnoid space alos was invaded by disseminated embryonal carcinoma. There have been seven other similar cases reported. All patients were males from five to 34 years of age.

Brain Neoplasms↗