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Biomedical subjects

Y Seki

Publications and source records attributed to Y Seki.

At least 163 records · Page 9Linked to original sources
PubMed1988

The prognostic significance of resection of primary tumor in gastric and colorectal cancer patients with synchronous liver metastasis.

The significance of primary tumor resection in gastric and colorectal cancer patients with liver metastasis (H(+)) was evaluated in terms of operative mortality and survival rate by dividing the materials [293 gastric cancer and 80 colorectal cancer patients (53 colon and 27 rectum) with synchronous liver metastasis] into the following groups: Firstly, with or without peritoneal dissemination (P), secondly, with or without resection of the primary tumor and thirdly, with or without postoperative adjuvant chemotherapy. The following results were obtained: (1) The direct operative death rate of primary tumor resection, excluding death from other causes, showed an absence of statistically significant differences between the P0H(+) and P(+)H(+) gastric and colorectal cancer patients. (2) There was no significance in the prognosis between the primary tumor resection + postoperative chemotherapy group and the non-resectable group in the P(+)H(+) gastric and colorectal cancer patients, revealing no prognostic value of the primary tumor. (3) In the P0H(+) gastric and colorectal cancer patients, the primary tumor resection + postoperative chemotherapy group was significantly more favorable in prognosis than was the primary tumor resection alone group or the non-resectable group, showing the value of primary tumor resection.

Adult↗
PubMed1988

[Bacterial intracranial aneurysms associated with infectious endocarditis--report of 3 cases].

Three cases of bacterial intracranial aneurysms associated with infective endocarditis are reported. All of the patients were successfully treated by various combinations of cardiac surgery, neurosurgery and chemotherapy with antibiotics. Case 1: A 39-year-old female was admitted with the complaint of sudden onset of severe headache following persistent fever of several month's duration. CT scan revealed a left frontal old hematoma and angiography detected an aneurysm located in the frontal ascending branch of the left middle cerebral artery. After 2 weeks' antibiotic therapy, the second angiography showed the aneurysm to be decreased in size. The third angiography, performed 2 weeks after cardiac valve replacement for infective endocarditis, demonstrated complete resolution of the aneurysm. Case 2: A 19-year-old male entered hospital with high fever and chills. In addition to infective endocarditis, CT scan and angiography revealed an aneurysm arising from the distal portion of the left posterior cerebral artery. The patient was treated with high dose antibiotics and then his general condition improved. However, angiography examined 4 weeks after the initial study demonstrated the aneurysm to be apparently enlarged. Therefore, the aneurysm was excised before cardiac surgery. Repeated angiography after valve replacement showed no further aneurysm. Case 3: A 30-year-old female was admitted on the diagnosis of infective endocarditis and meningitis. CT scan showed abnormal density areas in the right frontal lobe and the left temporal lobe.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Role of inhibition of uroporphyrinogen decarboxylase in PCB-induced porphyria in mice.

The oral administration of 3,4,5,3',4',5'-hexachlorobiphenyl for 3 weeks to mice caused a marked accumulation of porphyrins in the liver of C57BL/6 and C57Bl/10 mice but not in the liver of ddY mice. The time course of induction of delta-aminolevulinic acid synthetase (ALA-S), cytochrome P-450, and mixed function oxidases and inhibition of uroporphyrinogen decarboxylase (URO-D) in the liver of C57BL/6 mice and ddY mice fed a diet containing 500 ppm of a commercial PCB (Kanechlor-500) were investigated to clarify the sole factor in inducing porphyria. The activity of URO-D in the liver of C57BL/6 mice was depressed approximately 80% at 3 weeks when a large amount of uroporphyrin accumulated. Male ddY mice showed only a slight increase in uroporphyrin accumulation in the liver and a moderate decrease of URO-D activity even at the 10th week. ALA-S, cytochrome P-450, and mixed function oxidases were induced in both strains of mice, although the magnitude of these inductions in C57BL/6 mice was greater than that in ddY mice. No differences were detected between the two strains in the content and gas chromatographic pattern of PCB remaining in liver cytosol (6 weeks). In addition there was no relationship between the time of onset of porphyria and that of the maximal induction of drug-metabolizing function in C57BL/6 mice. These results indicate that the development of porphyria is causally related to the inhibition of URO-D rather than the induction of drug-metabolizing function. The hypothesis that porphyria first develops when the ratio of hepatic URO-D and ALA-S activities decreases to less than 1.0 is presented.

5-Aminolevulinate Synthetase↗
PubMed1987

A comparison of the melanocyte response to narrow band UVA and UVB exposure in vivo.

The visible cutaneous pigmentary response to ultraviolet-A (UVA) is immediate and, following sufficient exposure, may persist, whereas ultraviolet-B (UVB)-induced pigmentation appears after a delay of several days. We compared the in vivo response of melanocytes to single and multiple exposures of narrow band UVA and UVB irradiation which produced visibly equal increases in pigmentation. Using a xenon-mercury source matched to a monochromator, human volunteers were exposed to 304 (+/- 5) and 365 (+/- 10) nm radiation. Biopsies were performed 1, 7, and 14 days after irradiation. For each biopsy, the number of melanocytes per square millimeter of epidermis was determined using L-3,4-dihydroxyphenylalanine (dopa)- and tyrosine-incubated split epidermal preparations. Vertical sections were also examined. At days 7 and 14, after both 304 and 365 nm radiation, melanocytes were more intensely dopa-positive than in unirradiated controls, and demonstrated enlarged perikarya and a greater number of enlarged dendrites. Following both 304 and 365 nm radiation the number of dopa-positive melanocytes was increased at days 7 and 14 by 44% and 58%, respectively. Tyrosine positivity, an indicator of enhanced tyrosinase activity and increased melanin formation, was absent in controls and at day 1, and became positive in all but one sample at day 7 and day 14. Therefore, one day after UVA exposure, visible pigmentation but not tyrosinase activity was increased. At day 7, the number of tyrosine-positive melanocytes approximately equaled the number of dopa-positive melanocytes. Although UVA and UVB induce different pigmentary responses, their effects on melanocyte number and function were indistinguishable.

Adult↗
PubMed1987

Mechanism of PCB-induced porphyria and yusho disease.

PCBs are known to be potent inducers of chemical porphyria. We studied the structure-activity relationship of synthetic PCBs as porphyrin inducers and found that 3,4,3',4'-tetrachlorobiphenyl, 3,4,3',4',5'-pentachlorobiphenyl, and 3,4,5,3',4',5'-hexachlorobiphenyl were the most active inducers. The structural requirement for potent porphyrinogenic activity of PCB isomers was the substitution of chlorine atoms at the para and meta positions. Isomers fulfilling this requirement had more highly conjugated and nearly coplanar conformations. In addition, it was demonstrated that inhibition of UROD by the most active porphyrin inducers occurred in vitro using purified enzyme. These findings could explain how porphyrinogenic PCBs, by primarily inhibiting UROD and hence depleting heme, ultimately increase ALAS synthesis. The outbreak of yusho disease in Japan (which was caused by PCB-contaminated rice oil) and a similar episode of food poisoning in Taiwan (which was also related to PCB contamination) were discussed, particularly with reference to urinary porphyrin levels and clinical response.

5-Aminolevulinate Synthetase↗