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Biomedical subjects

Y Seki

Publications and source records attributed to Y Seki.

At least 127 records · Page 7Linked to original sources
PubMed1992

Intracranial seeding following surgery for spinal cord astrocytoma--case report.

We report a case of intracranial dissemination developing approximately 6 months after partial removal of a spinal cord astrocytoma in a 40-year-old male. The clinical course and postmortem findings indicate that the tumor originated in the cervical cord and extended into the subarachnoid space, first the spinal canal and later intracranially. Spinal cord glioma dissemination through the cerebrospinal fluid is more common than previously considered and indicates a dismal prognosis. An aggressive approach, including radical surgery, entire neuraxis irradiation, and adjuvant chemotherapy, is suggested as the initial treatment for malignant spinal cord glioma to prevent subsequent dissemination.

Adult↗
PubMed1992

An occupational hygiene survey in a Chinese viscose rayon factory.

The retinopathy (microaneurysm/small dot hemorrhage) is an early and specific biological indicator to quantitatively evaluate the CS2 exposure. The appearance of retinal lesions was observed among Yugoslavian, German and American workers exposed to CS2. However, among Finnish CS2 workers a positive result was not obtained. We suggested a different response to CS2 exposure between two ethnic populations. We had an opportunity to do a cross-sectional medical and occupational hygiene survey in a Chinese rayon staple plant. Cross-sectional medical examinations failed to show any chronic CS2 effects on the Chinese workers.

Adult↗
PubMed1992

Behaviour of tissue plasminogen activator, plasminogen activator inhibitor 1 and their complex in various disease states.

Plasma levels of tissue plasminogen activator (t-PA) antigen, plasminogen activator inhibitor 1 (PAI-1) antigen and t-PA/PAI-1 complex were measured in plasmas from 18 healthy subjects and 75 patients with various diseases (28 patients with haematological malignancies, 20 with thrombotic diseases, five with infectious diseases, four with liver diseases, ten with bleeding disorders and eight miscellaneous conditions). In addition, we studied ten patients with bleeding disorders after DDAVP infusion and 18 healthy subjects after venous occlusion. Plasma levels of t-PA antigen, PAI-1 antigen and t-PA/PAI-1 complex were increased in the patients compared with the healthy subjects. t-PA/PAI-1 complex levels correlated well with t-PA antigen levels and molar concentrations of t-PA antigen were similar to those of the t-PA/PAI-1 complex. Venous occlusion induced an increase in both t-PA antigen and PAI-1 antigen and the molar concentration of the t-PA/PAI-1 complex was equivalent to that of t-PA antigen. Following DDAVP infusion, the levels of t-PA antigen and t-PA/PAI-1 complex increased but PAI-1 antigen levels decreased, and the increase of t-PA antigen was greater than that of t-PA/PAI-1 complex. These findings indicate that PAI-1 antigen exceeds t-PA antigen in healthy subjects and in patients with various diseases. We conclude that part of the t-PA/PAI-1 complex is rapidly cleared from the circulation and that free t-PA increases after DDAVP infusion.

Adult↗
PubMed1992

[Discrepancy between 123I-IMP SPECT and X-ray CT in chronic cerebrovascular disease].

The discrepancy between the low accumulation area (LAA) seen on 123I-IMP SPECT and the low density area (LDA) on X-ray CT was evaluated in 76 cases with chronic cerebrovascular disease. In 19 patients, LAA was larger than LDA beyond the vascular territory. Brain angiogram showed either obstruction or stenosis of the major arteries in as many as 59 percentages of this discrepancy group. In many patients of this group, cortical neurological symptoms were observed. In 37 patients in which the size of LAA was equal to that of LDA, abnormality of the major arteries was observed in only 7 percentages. These results indicated that the discrepancy mainly reflected the infarction due to irreversible ischemic change of perforate artery with the cortical low perfusion caused by the major artery disease. In some patients, the discrepancy was believed to show the remote effect caused by neurological pathway disturbance.

Adult↗
PubMed1992

[On the fenestration of the vertebral and basilar arteries].

The fenestration of the vertebral and basilar arteries was investigated macroscopically in 370 human cases. Altogether 43 fenestrations were found in 32 (8.6%) out of 370 cases. The fenestrations could be divided in three groups according to the position where the fenestration appeared. Group I was the fenestration observed along the vertebral artery (Fig. 1), and 7 such fenestrations were found in 6 (1.6%) out of 370 cases; 3 fenestrations among them were located on the right side, 2 were located on the left side and 1 was found on the bilateral vertebral arteries. In 4 out of 7 fenestrations in this group, the hypoglossal nerve was found passing through the fenestration. Group II was the fenestration observed along the basilar artery (Fig. 2), and 26 fenestrations of this type were found in 20 (5.4%) out of 370 cases: 23 fenestrations (88.5%) were located at the caudal half, 3 (11.5%) were located on the rostral half of the basilar artery (Fig. 5). A close relation was indicated between the side on which the fenestration appeared in the basilar artery and the largeness in caliber of the vertebral artery of either side. Group III was the fenestration observed at the lateral area of the vertebral and basilar arteries (Fig. 3), and 10 fenestrations of this type were found in 9 (2.4%) out of 370 cases; all the fenestrations were located on the right side. In this group, the hypoglossal nerve was observed passing through the fenestratin in 4 out of the 10 fenestrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Recovery functions of fast frequency potentials in the initial negative wave of median SEP.

Following far-field potential of P14 after median nerve stimulation, we identified several small wavelets, designated here as fast frequency potentials or FFP, over the ascending and descending phases of the major negative wave of 'N20.' In 10 normal subjects who had well defined FFP, namely N16, N17, N18 and N19, we studied recovery functions of FFP by applying paired (condition and test) stimuli of various interstimulus intervals (ISIs) ranging from 3 to 150 msec. Recovery of FFP was determined by the difference wave forms, i.e., subtracting the response of conditioning stimuli from the response to paired stimuli. Measuring latencies and amplitude of FFP and also of the far-field potential of P14, we found recoveries of P14 and each FFP to be different; P14 recovered with the shortest ISI while progressively longer ISIs were required for full recovery of the later FFP. This finding suggests the existence of progressively increased number of interspersed synapses from the early to late FFP. It is unlikely that FFP represents passage of the afferent volley from one anatomical site to the next, but rather that they are cortically generated via a closely situated polysynaptic network. The polysynaptic nature of FFP is consistent with the observation that they disappear in sleep and also during anesthesia. The study indicates that FFPs represent different physioanatomical systems from the primary negative wave of 'N20' that results from specific sensory input to the primary sensory cortex.

Adolescent↗
PubMed1991

Lipid peroxidation and concentration of glutathione in erythrocytes from workers exposed to lead.

Lipoperoxide concentration in erythrocytes from workers occupationally exposed to lead (mean blood lead concentration 57.1 (SD 17.6) micrograms/dl) was significantly higher than that in controls. It was not different in plasma from the two groups. The activity of superoxide dismutase (SOD) and catalase in erythrocytes from workers exposed to lead was significantly lower than that of control subjects. The effect of lead was also seen in the glutathione concentration of erythrocytes from lead exposed workers, which was reduced to 69% of that found in erythrocytes from control workers. The increase in methaemoglobin content of erythrocytes from workers exposed to lead was less than expected and not significantly different from that of controls. A positive correlation between lipoperoxide concentration in erythrocytes and lead concentration in blood and a negative correlation between glutathione concentration in erythrocytes and blood lead concentration were found. Incubation of erythrocytes for 24 hours at 37 degrees C in the presence of lead (100 micrograms/dl) produced no changes in glutathione and lipoperoxide concentrations, although there was inhibition of activity of SOD (14.3%), catalase (10.1%), and glutathione peroxidase (35.1%). A similar experiment with heparinised whole blood showed increased haemolysis with no changes in membrane lipid peroxidation of erythrocytes. It is postulated that the lowered concentration of glutathione and decreased activity of SOD, catalase, and glutathione peroxidase in erythrocytes from workers exposed to lead may play a part in the increased membrane lipid peroxidation. Furthermore, the results suggest the possibility that leucocytes, or platelets, or both, may induce haemolysis in the presence of lead.

Catalase↗
PubMed1991

Primary intracranial amelanotic melanoma--report of an autopsy case.

Primary intracranial amelanotic melanoma was verified at autopsy in a 38-year-old male. Correct diagnosis of amelanotic melanoma needs electron microscopy or immunohistochemistry, since Masson staining is negative due to the absence of melanin pigment. We adopted the following criteria for clinical use: macroscopically not dark and microscopically negative for Masson staining, but ultrastructurally various melanoma types present. Although the clinical profile of this case is consistent with melanotic melanoma, the more detailed features of primary intracranial amelanotic melanoma require future study.

Adult↗
PubMed1991

Evaluation of methyl bromide exposure on the plant quarantine fumigators by environmental and biological monitoring.

The study was undertaken to assess the potential risk of exposure to methyl bromide (MB) gas of plant quarantine fumigators who wore full facepiece gas masks with respirator canisters. The mean ambient concentrations of MB determined by a personal sampling device exceeded the TLV-ACGIH level of 5 ppm in the degassing processes at three fumigation sites except at the silos. The mean urinary bromine concentration of 379 non-MB workers was 6.3 +/- 2.5 mg/l with 95% confidence limits of 10 mg/l. There were 44.6% of 251 MB workers whose urinary bromine levels exceeded the 10 mg/l. There was a significantly positive correlation between the urinary bromine concentrations of the MB workers and the ambient MB concentrations in the degassing process. The MB levels in the workers' exhalation were positive in the degassing process, while those were below the detection limit in the dispersion process. Three possible routes through which the workers are exposed to MB gas are considered to exist: leakage through the interstice between the facepiece of a gas mask and the wearer's face, breakthrough of MB gas in the respirator canister, and percutaneous absorption of MB gas. Biological monitoring of urinary bromine and exhalatory MB as well as environmental monitoring of the ambient MB provided useful information for evaluating exposure of workers to MB.

Air Pollutants↗
PubMed1991

[Combination cancer chemotherapy using a DNA topoisomerase inhibitor CPT-11, as a core agent--the in vitro evaluation].

CPT-11, a derivative of camptothecin, has drawn attention to cancer chemotherapy because of the specific mode of action, and the clinical study is now under progress. Liu et al. proved that camptothecin was a DNA topoisomerase I inhibitor, and some kinds of antitumor agents have been recognized as DNA topoisomerase II inhibitors. Based on these findings, DNA topoisomerases have emerged as target enzymes of antitumor agents in cancer chemotherapy. This paper dealt with investigation on the cytotoxic effects induced by combined use of DNA topoisomerase targeting antitumor agents, especially using CPT-11 as a core antitumor agent. Synchronous administration of CPT-11 with other antitumor agents induced cytotoxic effects less than metachronous administration of CPT-11 with other antitumor agents, especially preceding use of CPT-11. Dose of antitumor agents was not necessarily correlated to the cytotoxic effects. In some instances, small doses of the agents showed better therapeutic effects than large doses. The cytotoxic effects of vincristine, vindesine, and hydroxyurea were reduced by combination with CPT-11. On the other hand, non-cytotoxic agents such as aphidicolin, novobiocin, propentofylline, pentoxifylline, norfloxacin, and tosufloxacin enhanced the cytotoxic effects of CPT-11. Hypothetical consideration of cell killing and acquisition of drug resistance was proposed.

Antineoplastic Agents, Phytogenic↗
PubMed1991

Taxonomic properties of five Kitasatosporia strains isolated by a new method.

Kitasatosporia strains were found to be resistant to an antibiotic, novobiocin. By a new method using novobiocin-containing agar medium, five Kitasatosporia strains, SK-3255, OM-5023, SK-3406, SK-3412 and SK-3421 were efficiently isolated from soils. These five strains were characterized in common by Rectiflexibiles, spores cylindrical with smooth surfaces, and no melanin formation. Two strains, SK-3255 and OM-5023 were taxonomically different from known species of the genus Kitasatosporia, while the two strains, SK-3406 and SK-3412 and the remaining strains SK-3421 were identified with K. phosalacinea and K. papulosa, respectively.

Actinomycetales↗
PubMed1991

[Catheter-in-catheter replacement technique for bronchial arterial continuous infusion therapy for pulmonary malignancies].

The purpose of this study was to improve tumor effects and to reduce side effects caused by one shot bronchial arterial infusion therapy for pulmonary malignancies. The catheter-in catheter replacement technique in proper bronchial artery was introduced for infusion therapy for several hours for this purpose. Three kinds of combination of catheters were selected and the duration of replacement in bronchial artery was either eight or 24 hours. In eight patients of 12 patients with pulmonary malignancies superselective bronchial arterial infusion was carried out through the inner small catheter. No significant complications developed either at the time of replacement or during continuous infusion.

Adult↗
PubMed1990

Lichen planus pemphigoides: case report and results of immunofluorescence and immunoelectron microscopic study.

A Japanese woman with lichen planus pemphigoides is reported. Immunologic characteristics of lichen planus pemphigoides antigen in the patient were investigated by indirect immunofluorescence and compared with those of bullous pemphigoid antigen or epidermolysis bullosa acquisita antigen. Ultrastructural localization of lichen planus pemphigoides antigen was studied with the use of immunoelectron microscopic techniques. Lichen planus pemphigoides antigen showed localization similar to that of bullous pemphigoid antigen but different from that of epidermolysis bullosa acquisita antigen. The antigenic stability of lichen planus pemphigoides antigen was different from that of bullous pemphigoid antigen or epidermolysis bullosa acquisita antigen. Thus this study demonstrates that lichen planus pemphigoides antigen is different from bullous pemphigoid antigen.

Aged↗
PubMed1990

Collateral drug sensitivity induced in CPT-11 (a novel derivative of camptothecin)-resistant cell lines.

Collateral drug sensitivity was induced in CPT-11-resistant cell lines (CPT-K and T). Ten of the 19 kinds of antineoplastic agents (especially, 5 of 6 kinds of DNA topoisomerase II inhibiting agents) were effective in inducing collateral drug sensitivity. Alteration of DNA topoisomerase I seemed to be unrelated to acquisition of multidrug resistance.

Antineoplastic Agents, Phytogenic↗
PubMed1990

Transcranial magnetic stimulation of the facial nerve: recording technique and estimation of the stimulated site.

We compared transcranial magnetic and conventional electrical stimulation in 20 facial nerves of 10 normal subjects. A magnetic coil was placed tangentially over T5 or T6 (10-20 electroencephalogram electrode placement system) and electrical stimulation was applied 1 cm below the anterior tragus. Compound muscle action potentials recorded from the ipsilateral nasalis muscle showed onset latencies (mean +/- SD) of 4.48 +/- 0.50 ms with magnetic stimulation and 3.15 +/- 0.40 ms with electrical stimulation, a mean difference of 1.33 +/- 0.14 ms. Stimulation of the extracranial facial nerve at two sites yielded a conduction velocity of 59.6 +/- 4.5 m/s. Based on these findings, the magnetically stimulated site was estimated to fall 79.0 +/- 8.6 mm proximal to the point of electrical stimulation. Taking the average length of the nerve trunk and histological specificity of the root exit zone into consideration, evidence indicates that the root exit zone of the facial nerve is the most likely initiating site of excitation with magnetic stimulation.

Action Potentials↗