Biomedical subjects

K Shouji

Publications and source records attributed to K Shouji.

8 recordsLinked to original sources

PubMed2001

Therapeutic effects of simultaneous intraluminal irradiation and intraluminal hyperthermia on oesophageal carcinoma.

An applicator enabling simultaneous intraluminal radiotherapy and intraluminal hyperthermia delivery was developed to improve the treatment results for locally advanced oesophageal carcinoma. Eight inoperable cases were treated by this method. Six cases received 40 Gy external irradiation followed by simultaneous intraluminal hyperthermia and radiotherapy (3 Gy and 4 Gy in three cases each) once weekly for 3 weeks; the remaining two cases received 50 Gy external irradiation followed by simultaneous intraluminal hyperthermia and radiotherapy (4 Gy) once weekly for 2 weeks. Hyperthermia was delivered by a radiofrequency current thermotherapy instrument for 30 min at an output that raised the oesophageal mucosal surface temperature to 42-43 degrees C. Intraluminal radiotherapy was delivered with a microSelectron to a submucosal depth of 5 mm after the first 15 min of hyperthermia. Four cases achieved complete response, with all demonstrating local control. Partial response was obtained in four cases, and three of these patients died of local recurrence. There were no significant adverse side effects apart from fistula in one case. In conclusion, simultaneous intraluminal radiotherapy and hyperthermia may improve the current treatment results for locally advanced oesophageal carcinoma.

Aged↗

PubMed1998

Platelet-activating factor is a key mediator of pulmonary vasoconstriction and bronchoconstriction after antigen challenge in the perfused sensitized rabbit lung.

Exposure of sensitized perfused rabbit lungs to human O-N type erythrocytes leads to pulmonary vasoconstriction and bronchoconstriction. To investigate whether platelet-activating factor (PAF) is a mediator of pulmonary vasoconstrictive and bronchoconstrictive responses after antigen challenge, we administered antigenic erythrocytes after the administration of PAF antagonist (.1 mg/kg; CV6209). Pulmonary arterial and airway pressures significantly increased after antigen challenge in the sensitized rabbit lungs, but not in the nonsensitized rabbit lungs. CV6209 significantly inhibited these pulmonary vasoconstrictive and bronchoconstrictive responses after antigen challenge. We concluded that PAF, at least in part, plays an important role in pulmonary vasoconstriction and bronchoconstriction after antigen challenge in rabbits.

Animals↗

PubMed1997

High dose rate endobronchial brachytherapy using a new applicator.

BACKGROUND AND PURPOSE: To obtain adequate spatial dose distribution for endobronchial brachytherapy, we applied reference dose points according to the bronchial diameter. For this purpose, we devised a new applicator of which the source transfer tube is contained in the center of the lumen for high dose rate (HDR) brachytherapy. MATERIALS AND METHODS: Thirty-nine patients with endobronchial cancer underwent endobronchial brachytherapy using an HDR afterloading machine with an Ir-192 source. In the nine patients treated with curative intent, treatment consisted of external beam radiotherapy with 40-60 Gy for 4-6 weeks and endobronchial brachytherapy with three fractions of 6 Gy. The 30 patients treated with palliative intent received one fraction of 10 Gy with or without external beam irradiation. The reference dose points were prescribed according to bronchial diameter, which was measured by the applicator's radiopaque wing expansion reflecting the bronchial caliber. RESULTS: The new applicator could be placed at the intended site in 37 lesions. Of 12 lesions which were treated with curative intent, eight (67%) disappeared after brachytherapy. The overall survival at 3 years of all patients and of the patients treated with curative intent was 22 and 64%, respectively. CONCLUSIONS: The source should be positioned in the center of the lumen; this technique is helpful in reducing side-effects caused by inhomogeneous dose distribution of endobronchial brachytherapy.

Adult↗

PubMed1996

[Endobronchial brachytherapy with high dose rate 192Ir afterloading technique using a new applicator].

Recently, high dose rate endobronchial brachytherapy has been carried out for the treatment of lung cancer. We devised a new applicator for Ir-192 high dose rate brachytherapy that can position the source in the center of the bronchial lumen, and tried to set up reference points according to bronchial diameter, for optimal dose distribution. Treatment consisted of external beam radiotherapy (40-60 Gy in 4-6 weeks) and endobronchial brachytherapy (6 Gy x 3 fractions for curative intent, 10 Gy x 1 fraction for palliative intent). Reference dose points were 3, 5, 7 and 10 mm from the center of the source according to bronchial diameter. We treated 19 patients with endobronchial brachytherapy and used the new applicator in 13 of them. We could place the applicator in all 13 patients, and no remarkable side effects were observed during the observation period. Our newly designed applicator will help to reduce radiation side effects caused by irradiation overdose due to adherence of the source to the bronchial wall. The reference point should be set according to bronchial diameter not only for curative intent but also palliative intent.

Brachytherapy↗

PubMed1995

Inhibition of pulmonary hypertensive response after antigen challenge.

By adding antigen cells into perfusate circulation, a great increase in pulmonary arterial pressure was observed in isolated perfused lung from rabbits previously immunized with human O-N type erythrocytes. To investigate whether thromboxane A2 is the main mediator in pulmonary vasoconstrictive response, we injected antigen erythrocytes into the reservoir after administration of putative inhibition as follows: indomethacin (5 mg/kg, thromboxane A2 synthetase inhibitor), KT2-962 (.1 mg/kg, thromboxane receptor blocker), and pyrilamine (.1 mumol, H1 blocker). Pulmonary vasoconstrictive response after antigen challenge was significantly blocked by both indomethacin and KT2-962, but not by H1 blocker. Although the H1 blocker, pyrilamine, did not significantly block the pulmonary vasoconstrictive response, it did significantly block the bronchoconstrictive response after antigen challenge; however, the bronchoconstrictive response was not blocked by either indomethacin or KT2-962. We conclude that thromboxane is the main mediator in the pulmonary vasoconstrictive response, and histamine is the main mediator in the bronchoconstrictive response.

Animals↗

PubMed1995

[Pulmonary hypertensive responses to erythrocytes components in sensitized rabbits].

Antigen erythrocytes cause a transient pulmonary hypertension in sensitized rabbits. We investigated the main responsible component in the antigen erythrocytes. Eleven rabbits were immunized intravenously with human O-N type erythrocytes every ten days until the agglutinin titer = 1:8,000 was obtained. Another ten rabbits without immunization served as a control group. Human erythrocytes were osmolitically hemolyzed and then separated into hemoglobin and membrane components by centrifugation. In sensitized rabbits, a bolus injection of human hemoglobin 0.7 ml.kg-1 caused increases in pulmonary arterial and airway pressures within 3-4 min. Increase in pulmonary arterial pressure after injection of hemoglobin component was significantly higher than that after injection of membrane component in sensitized rabbits. However, in nonsensitized rabbits both components were ineffective. Leukocytes counts decreased by 73-62% in sensitized rabbit, while they decreased by 16-37% in nonsensitized rabbits 5 min after injection of hemoglobin or membrane component. Platelets decreased by 54-61% in sensitized rabbits, while they decreased by 24-9% in nonsensitized rabbits 5 min after injection of hemoglobin or membrane component. We conclude that hemoglobin is the responsible component in the antigen erythrocytes and chemical mediators, such as thromboxane and platelet activating factor, may not be released from platelets and leukocytes.

Airway Resistance↗

PubMed1995

[Simultaneous intraluminal irradiation and hyperthermia treatment for esophageal carcinoma].

The combination of radiotherapy and thermotherapy has the greatest antitumor effect when delivered simultaneously. We developed and have clinically used an applicator that enables simultaneous intraluminal irradiation and hyperthermia delivery for the treatment of locally invasive esophageal carcinoma. In a phase 1 study, 40 Gy of external irradiation was delivered followed by simultaneous intraluminal hyperthermia and radiotherapy once weekly for three weeks. Intraluminal hyperthermia was delivered to the mucosal surface at 42 to 44 degrees C for 30 minutes. Intraluminal irradiation (3 Gy) was delivered to a submucosal depth of 5 mm after the first 15 minutes of hyperthermia. This treatment may increase current treatment results for locally invasive esophageal carcinoma, which have otherwise been maximized.

Aged↗

PubMed1991

[Effect of isoflurane on muscle relaxation in a patient with myotonic dystrophy].

We did anesthetic management by isoflurane for total thyroidectomy under the neuromuscular transmission monitoring in a patient with myotonic dystrophy. In three patients without neuromuscular disorders, T1 was 85% of control and fade was not observed, while in this case T1 was 40% of the control and TOFR was decreased to 50%. We conclude that isoflurane has a good muscle relaxation effect in this disease and, we could manage without administering any muscle relaxants.

Adult↗