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Biomedical subjects

H Seto

Publications and source records attributed to H Seto.

At least 181 records · Page 10Linked to original sources

Diurnal rhythms in calcium and phosphate metabolism in rodents and their relations to lighting and feeding schedules.

Diurnal fluctuations in serum Ca, inorganic phosphorus, Mg, and alkaline phosphatase activity and their relations to lighting and feeding schedules were investigated in nocturnal rats and diurnal asiatic chipmunks. The following results were obtained: all parameters in the animals fed ad libitum and adapted to a regulated light-dark cycle (with light from 7.00 to 19.00 h) showed diurnal rhythms; under the same experimental condition, the patterns of the rhythms in the nocturnal rat and the diurnal asiatic chipmunk were nearly 180 degrees out of phase with each other; under the continuous lighting condition for more than 10 days, the diurnal rhythms of the parameters in rats decreased in their amplitudes, and phase shifts or marked modulations in the diurnal curves occurred when the time of availability of food was restricted from 9.00 to 17.00 h without altering the lighting schedule. The above findings support an idea that the rhythmicity is one of the essential features involved in the Ca metabolism. It is demonstrated that the environmental photofraction is one of the essential factors in generating or in maintaining the circadian rhythm of Ca metabolism as in other physiological processes and that the feeding time also could have a marked effect on the diurnal rhythm in the Ca metabolism.

Alkaline Phosphatase

[Internal carotid aneurysmal formation following spontaneous regression of the dural arteriovenous malformation in the posterior fossa--a case report].

The patient was first admitted on August 19, 1975 with 5 years' headache and tinnitus. Physical examination revealed bruit over the left mastoid area. Left angiography, performed in August, 1975, revealed a dural arteriovenous malformation, which was supplied by enlarged left middle meningeal artery, occipital artery, meningohypophyseal artery and superior cerebellar artery and was draining into the left sigmoid sinus. At the first operation, the left external carotid artery was ligated at the neck, and then coagulation of dural vessels was performed through left temporo-occipital craniotomy. Tinnitus and bruit were disappeared after operation. Postoperative right angiogram showed no residual dural AVM, however, ligation of the right external carotid artery was required to reduce symptomes. In June, 1979 the left brachial arteriography was performed, and revealed a dural AVM around the left sigmoid sinus supplied by anastomotic vessels between external carotid artery and cervical artery arising from the vertebral artery. Because of subarachnoid hemorrhage, repeated angiography in April, 1982, revealed progressively enlarging dural AVM, although no aneurysm was seen in the left internal carotid arterial system. The patient readmitted on October, 28, 1983 with severe headache and confusion. CT scan showed slightly high density in the left basal cistern. Angiogram showed no dural AVM and a saccular aneurysm arising from the left internal carotid artery at C2 portion, which was successfully clipped by surgery. Only two cases of spontaneous regression of dural AVM in the posterior fossa were reported previously, and the authors added a case, which showed a newly developed aneurysm after spontaneous regression of the posterior fossa dural AVM.

Carotid Artery Diseases

Glycolipid composition of ascitic fluids from patients with cancer.

The glycolipid composition of ascitic fluids from nine patients with cancer and one pleural effusion from a hepatoma patient was studied. Glucosylceramide, lactosylceramide, globotriaosylceramide, and globotetraosylceramide were found in all samples and also in normal human serum. These glycolipids accounted for more than 90% of the neutral glycolipid fraction and the composition in ascitic fluids was similar to that in normal human serum. From ascitic fluids, several minor glycolipids, which could not be detected in normal human serum, were isolated and characterized by exoglycosidase treatment. Lactoneotetraosylceramide was found in eight samples of ascitic fluids, and globopentaosylceramide was detected in two samples from hepatoma and one from pancreatic cancer. A fucolipid which was converted to lactoneotetraosylceramide by alpha-L-fucosidase treatment was recognized in two samples from hepatoma patients. In the ganglioside fraction, GM3 was the predominant component both in normal human serum and in ascitic fluid. The GM2 content in ascitic fluids was much higher than that in normal human serum. From these results, lactoneotetraosylceramide and GM2 are possible candidates as cancer markers, because they seemed to be derived from cancer tissues by shedding.

Ascites