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M Samejima

Publications and source records attributed to M Samejima.

77 records · Page 5Linked to original sources

Embolotherapy for persistent hemoptysis: the significance of pleural thickening.

Elective embolotherapy for recurrent hemoptysis was evaluated for its effectiveness. Forty embolotherapeutic procedures were performed in 30 patients. In the short term, complete hemostasis was achieved in 16 of 40 procedures (40%) and significant improvement in another 16 procedures (40%). Long-term, complete hemostasis was achieved in 14 of 34 procedures (41%) and significant improvement in 12 (35%). Embolotherapy was consistently more effective in patients who had no pleural abnormalities compared with those with pleural thickening. Long-term complete hemostasis was achieved in 7 of 10 procedures (70%) for the patients without pleural thickening and only 7 of 24 (29%) in patients with pleural thickening. Thus, pleural abnormalities negatively influence long-term effectiveness of embolotherapy.

Adult↗

Effects of cGMP and cAMP on light responses of the photosensory pineal neurons in the lamprey, Lampetra japonica.

We examined in this study how external cyclic nucleotides affect the light response mechanism of the pineal photoreceptors and explored the existence of parietal eye type of photoreceptor of which the internal cGMP concentration increased during the light response. Pineal organs of river lampreys, Lampetra japonica, were treated with 8-bromo guanosine 3',5'-cyclic monophosphate (8Br-cGMP) or 8-bromo adenosine 3',5'-cyclic monophosphate (8Br-cAMP) before light stimuli, and the light responses were recorded from the second order neurons, chromatic or achromatic-type neurons. Excitatory and inhibitory light responses of the chromatic-type neuron became obscure by 9 and 3 mM 8Br-cGMP without changing the spontaneous spike discharge in the dark. 8Br-cAMP (3 mM) increased the frequency of spontaneous spike discharge, though it did not inhibit the light responses themselves. The inhibitory light response of the achromatic-type neuron decreased after adding 3 mM 8Br-cGMP, and it was unchanged by 3 mM 8Br-cAMP. The spontaneous spike discharge of the neurons in the dark was not affected by the cyclic nucleotides. The mechanism of these results can be explained if cGMP is an intracellular second messenger of light responses in the pineal photoreceptors and the blocking effect on photoresponses by externally applied 8Br-cGMP is caused by compensating for the reduction in intracellular cGMP by light. However, it does not indicate that the parietal eye type of photoreceptor found in lizard participates in the chromatic and achromatic-type responses in the lamprey pineal organ.

8-Bromo Cyclic Adenosine Monophosphate↗

Three-dimensional reconstruction of serotonin-immunoreactive photoreceptors in the pineal organ of the river lamprey, Lampetra japonica.

Serotonin-immunoreactive (5-HT IR) photoreceptors are present in the pineal complex (pineal and parapineal organ) of the river lamprey, Lampetra japonica. They are so-called modified pineal photoreceptors and have been regarded as photoneuroendocrine cells which secrete melatonin. We reconstructed 5-HT IR cells with a computer to demonstrate their three-dimensional structures from optical sections taken by a confocal laser scanning microscope. The 5-HT IR cell possesses a basal process, and it appears that the process does not branch out. These processes contact each other at the basal region of the end vesicle, and a process extends to the soma of the neighboring 5-HT IR cell. These findings were obtained by three-dimensional analysis with a computer, which is a useful technique to demonstrate the interaction between cells. We suggest that the 5-HT IR photoreceptors interact with one another.

Animals↗

Melatonin excretion rhythms in the cultured pineal organ of the lamprey, Lampetra japonica.

Pineal organ of the lamprey, Lampetra japonica, is essential to keep the circadian locomotor activity rhythm as previously reported. In this paper, we tried to show that an endogenous oscillator is located and is working in the pineal organ. When the pineal organs were excised and cultured in a plastic tube with M199 medium at 20 degrees C, melatonin secretion rhythms were clearly observed under both light-dark and continuous dark conditions. The circadian secretion of melatonin continued for more than five cycles under the continuous dark condition. This indicates that the pineal organ has an endogenous oscillator and that the melatonin secretion rhythm is controlled by this oscillator. These findings suggest the possibility that the locomotor activity rhythm of the lamprey is under the control of the oscillator in the pineal organ.

Animals↗