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Biomedical subjects

K Ueda

Publications and source records attributed to K Ueda.

At least 1,603 records · Page 89Linked to original sources
PubMed1979

The mechanism of the riboflavin sensitized photodestruction of mitomycin C.

A detailed in vitro study was made of the riboflavin sensitized photodestruction of mitomycin C. The dependences of the quantum yield in the system were examined on the introduction of various amounts of quenchers, such as halogen ion, paramagnetic ion, 1,4-diazabicyclo[2,2,2]octane, 2,6-di-tert-butyl-p-cresol, and p-hydroquinone. The results are consistent with a mechanism involving oxygen molecule in the excited singlet state as the photochemically reactive species. The rate constant of the reaction between the excited singlet oxygen and mitomycin C was calculated to be 8.9 x 10(9) M-1.S-1.

Cations, Divalent↗
PubMed1979

The specialized junctions between Merkel cell and neurite: an electron microscopic study.

Longitudinal serial sections of one half of the entire sinus hair of a mouse were examined by the electron microscope. Three neurites entering the outer root sheath from the perifollicular blood sinus were encountered. These were separate nerve trunks from those connected with perifollicular tactile nerve endings and exclusively innervated intrafollicular Merkel cells. Two types of specialized junctions were observed at the contact regions between Merkel cell plasma membrane and neurite plasma membrane: (i) desmosome-like structures in which small clear vesicles and/or the large cored vesicles of neurite and thicker membrane (post-synaptic?) of apposed Merkel cell were found ant (ii) synapse-like structures in which Merkel cell granules were concentrated near the plasma membrane and the membrane of the apposed neurite was usually thicker (post-synaptic?). In some of the synapse-like junctions the limiting membrane of Merkel cell granules fused with the Merkel cell plasma membrane and its content seemed to be discharged into the intercellular space. This suggested actual exocytotic secretion of Merkel cell granules. Juxtaposition of 2 types of junctions, i.e. (i) and (ii) above, was also found. This suggested the possibility that the reciprocal synapse would be present between Merkel cells and afferent neurites.

Animals↗
PubMed1979

Runaway pacemaker. A case report with a runaway rate of 2100 ppm.

A case of runaway pulse generator is described. A Vitalith C-23 developed runaway on the 13th postoperative day, without any preceding changes in the rate or amplitude of the pulse generator spike. The rate of runaway was 2100 pulses per minute (ppm), one of the highest rates ever reported. The ventricle was not captured by the runaway pulse generator, but was paced effectively by a temporary demand pacemaker (Medtronic 5880A) which was left in case of displacement of the implanted pacing lead. The reasons why the temporary pacemaker was not inhibited are discussed.

Aged↗
PubMed1979

Disseminated epidermolytic acanthoma.

A 65-year-old Japanese male suffered from numerous brownish papules on his back for 6 months. Clinical appearance resembled seborrheic keratosis, but light microscopic examination revealed epidermolytic hyperkeratosis. Electron findings were the same as those of epidermolytic hyperkeratosis and systemic nevus verrucosus. It may be concluded that this type of skin disease is an acquired epidermolytic hyperkeratosis.

Aged↗
PubMed1979

Suppression of tuberculin reactivity during natural rubella. Observations with 54 patients.

Fifty-four patients with previously positive tuberculin reactions were followed for tuberculin sensitivity, between the incubation period of natural rubella and the 40th day after the onset of rash. In many instances, tuberculin sensitivity was partially or completely depressed beginning in the incubation period and extending for up to 4 weeks after rash onset. Two of 3 cases of subclinical rubella infection also showed this phenomenon. The highest incidence of negative reactions was 83% in the first 3 days after rash onset. A few subjects had a larger skin reaction to tuberculin than the baseline reading during the 2 to 5 weeks after rash onset.

Adolescent↗
PubMed1979

Salicylate intoxication and influenza in ferrets.

A model of salicylate intoxication was developed in ferrets to permit the evaluation of the interaction with viruses isolated from patients with Reye's syndrome. Salicylate intoxication produced a mild elevation of the serum glutamic oxaloacetic transaminase and fatty changes in the liver, but these changes differed from those seen in Reye's syndrome on light and electron microscopy. Salicylates were associated with decreased activity of hepatic phosphorylase and a slight depression of activity or ornithine transcarbamylase, a mitochondrial urea cycle enzyme. Infection with influenza viruses produced mild fatty changes in the liver, but did not significantly potentiate the effects of salicylate intoxication on the over-all mortality, the degree of fatty changes, or the hepatic enzymes. Influenza infection alone was not associated with decreased hepatic phosphorylase activity, but was associated with decreased activity of ornithine transcarbamylase. Influenza A was isolated from the livers of two of four animals cultured in embryonated eggs.

Animals↗
PubMed1979

Carotid and vertebrobasilar transient ischemic attacks: clinical and angiographic correlation.

Carotid and vertebrobasilar transient ischemic attacks (TIAs) were clinically and angiographically correlated in 85 patients who had four-vessel angiography within 2 weeks after a TIA. The patients were divided into carotid and vertebrobasilar groups by clinical criteria. In the correlations of symptoms with arteriography, lesions of the contralateral internal carotid artery were observed in 54 percent of the patients. Of 39 patients with vertebrobasilar symptoms, 34 percent also had one carotid lesion and six patients had combinations of symptoms of both carotid and vertebrobasilar disease. In correlation with carotid bruits of the 85 patients, bruits were heard over one carotid artery in 42 percent. Subclavian bruits were heard in 47 percent of the patients with vertebrobasilar symptomatology. TIAs owing to arteriosclerosis of the cervical arteries occurred in 85 percent of the patients, but there was no significant difference in the incidence of atherosclerosis-induced TIA in the carotid and vertebrobasilar systems. For accurate population surveys of the prevalence of TIAs, and for clinical decisions, proper categorization of patients is necessary.

Adolescent↗
PubMed1979

Electrophysiologic study and prognosis of chronic bifascicular block.

Thirty patients (22 males and 8 females, aged 64 to 89 years) with chronic bifascicular block were studied electrophysiologically and prognosis was assessed. Three had RBBB with LPH, 17 had RBBB with LAH, and 10 had LBBB. AH interval was prolonged in 12 (43%) of 28 patients and HV interval was prolonged in 11 (37%) of 30 patients. Of 16 patients with first or second degree AV block, 11 (69%) had prolonged AH interval and 8 (50%) had prolonged HV interval. Effective refractory period of the right atrium was prolonged in 8 (50%) of 16 patients and that of atrioventricular node was prolonged in 9 (64%) of 14 patients. Second degree AV block was observed at lower rates of atrial pacing (130 beats/min or less) in 14 (74%) of 19 patients. Sinus node dysfunction was present in 16 (62%) of 26 patients. During the follow-up period (37.1 +/- 6.1 months), advanced or complete AV block developed in 2 of 27 patients (2.4% per year) and a patient died of acute myocardial infarction (1.1% per year). The present study showed that prolongation of AH interval was observed more frequently than that of HV interval, and the presence of widespread lesions in the conduction system was suggested in chronic bifascicular block, and in spite of these facts prognosis was not so unfavorable as reported previously.

Aged↗