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Biomedical subjects

K Miyagi

Publications and source records attributed to K Miyagi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Management of the heart rate during coronary artery bypass grafting on the beating heart: newly devised methods of decreasing heart rate--a preliminary report-.

BACKGROUND: To develop new methods for achieving bradycardia, we studied the feasibility of producing transient, reversible bradycardia with atrial stimulation and cooling of the sinoatrial node. METHODS: In an animal study, the atrium was stimulated electrically during the refractory period of the atrioventricular node. Alternatively, an area of the sinoatrial node was cooled regionally. The two methods were also performed in combination. In a clinical study, atrial stimulation was applied in seven consecutive patients who underwent coronary artery bypass grafting (CABG). RESULTS: In the animal study, atrial stimulation was effective only when 2 mg/kg of diltiazem was administered. Such atrial stimulation decreased heart rate (beats/minute) from 95.8+/-16.9 to 64.2+/-20.0 (the average reduction from the control value 66.1+/-10.3%). Cooling the sinoatrial node decreased heart rate, and was effective with or without administration of diltiazem. Heart rate was decreased from 156.6 31.7 to 110.7+/-21.7 (average reduction from control value 71.3+/-9.2%) before using diltiazem and from 102.0+/-11.9 to 63.5+/-13.9 (average reduction from control value 62.0+/-10.4%) after administration of diltiazem. By combining the two methods, heart rate was decreased from 102.0+/-12.3 to 44.6+/-9.1 (average reduction from control value 43.5+/-6.3%). In our clinical study, the atrial stimulation method was effective. CONCLUSION: Atrial stimulation or regional cooling of the sinoatrial node slowed the heart rate. By combining the two methods, the heart rate was slowed to 40. Clinically, atrial stimulation was effective in CABG patients.

Aged↗
PubMed2000

Cytotoxic effect through fas/APO-1 expression due to vitamin K in human glioma cells.

Congeners of vitamin K have been found to inhibit growth in various rodent and human tumor cells, but the mechanisms of the inhibitory action are still not well understood. To investigate the modes of actions of vitamin K, we used several vitamin K analogs and examined their cytotoxic effect for human glioma cell lines RBR17T and U251. The analogs included vitamin K1 (VK1), vitamin K2 (VK2), vitamin K3 (VK3), and geranylgeraniol (GGO) which form an unsaturated side chain of VK2. Cell viability was estimated by MTT assay. DNA fragmentation was demonstrated by gel electrophoresis and flow cytometry. In order to study the mechanism of apoptosis, we measured the changes of intracellular reactive oxygen intermediates (ROI) and Fas/APO-1 expression by flow cytometry. The results showed: (1) VK2, VK3, and GGO inhibited cell growth; (2) VK3 had a more potent cytotoxic effect than VK2, and VK3 enhanced the cytotoxic effect of antitumor agents (ACNU and IFN-beta) in RBR17T cells; (3) VK2, VK3, and GGO induce apoptosis: (4) VK3 increased the expression of Fas/APO-1 although VK2 and GGO did not increase its expression in glioma cells; (5) VK3 increased the production of intracellular ROI. Catalase and reduced glutathione (GSH) inhibited production of intracellular ROI and antagonized inhibition of cell-growth induced by VK3, but failed to antagonize that of VK2 and GGO. We hypothesize that VK3 induces apoptosis by promoting the generation of intracellular ROI and Fas/APO-1 expression. On the other hand, VK2 and GGO induce apoptosis but most likely by some other unknown pathway.

Antifibrinolytic Agents↗
PubMed2000

Comparison of contractile responses relative to protein between isolated diabetic and non-diabetic rat aortae to KCl and alpha-adrenoceptor agonists in different extracellular calcium concentrations.

The influence of extracellular Ca2+ concentration on contractile responses of aortae isolated from diabetic rats to KCl and alpha-adrenoceptor agonists was compared with that of non-diabetic rat aortae. Diabetic rats 6 weeks after administration of streptozotocin showed significantly lower body weight and higher plasma glucose concentration, but the protein content per each aortic ring preparation was not significantly different from that of non-diabetic preparation. Both diabetic and non-diabetic aortae showed concentration-dependent contractile responses to norepinephrine, which were concentration-dependently inhibited by prazosin. On the other hand, clonidine induced small contractions in both aortae, which tended to be more inhibited by prazosin than yohimbine. In non-diabetic aortae, the contractile responses to KCl, norepinephrine, methoxamine and clonidine were significantly greater with 2.5 mmol/l of extracellular Ca2+ than 1.25 mmol/l. In diabetic aortae, however, the contractile responses were not significantly influenced by changes in extracellular Ca2+ concentration. Additionally, the contractile responses to each agonist were markedly greater in non-diabetic aortae than diabetic ones. The present results indicate that the contractions of diabetic vasculature do not respond to changes in extracellular Ca2+ concentration, suggesting that there may be some impairment of Ca2+ related mechanisms.

Adrenergic alpha-Agonists↗
PubMed2000

Brain metastasis of epithelioid sarcoma--case report.

A 20-year-old-female first presented with an epithelioid sarcoma of the right thumb, and the right thumb was amputated. Five years later, a metastasis was found in the right lower lung and a partial lobectomy was performed. Three years later, computed tomography showed a metastatic brain tumor in the left frontal lobe, which was removed surgically. Adjuvant radiotherapy and chemotherapy were given after all operations. Histological examination showed all resected tumors were epithelioid sarcoma. She has maintained a good activity of daily living level as an outpatient for 2 years, although subcutaneous metastases and bronchial lymph node metastases have been observed. Such intensive treatment of slowly growing tumors often prolongs survival time, even in patients with multiple metastases.

Activities of Daily Living↗
PubMed2000

[Relapse of small cell carcinoma of the lung with metastasis to iris].

We reported a case of small cell carcinoma of the lung with metastasis to the iris during a stage of complete remission obtained with chemotherapy and radiation therapy. The patient was a 55-year-old man hospitalized for hoarseness and abnormal chest radiographs in August 1996. Small cell carcinoma of the lung had been diagnosed, and the stage was limited disease. Treatment consisted of 3 cycles of chemotherapy with cisplatin and etoposide, together with radiation therapy. The patient achieved complete remission and was discharged. In mid-December, he visited an eye clinic with the complaints of blurred vision and congestion in the right eye. Metastatic tumor of the iris was diagnosed. At that time, neither local recurrence of the lung cancer nor metastasis to other organs were observed. The patient was treated with cisplatin and etoposide again, resulting in a reduction of the iris tumor's size. After chemotherapy, the right eye was treated with electron irradiation, and the iris tumor and other clinical signs almost entirely disappeared. The patient retained normal vision during the clinical course.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Surgical treatment of traumatic aneurysm of the ascending aorta.

Traumatic aneurysm of the ascending aorta is a rare event. This case describes a patient with such an aneurysm, resulting from injuries received in a motorcycle accident. The patient was admitted to the emergency room of a local hospital complaining of chest pain, and was subsequently referred to our institution. On admission, a chest x-ray showed mediastinal widening. Computed tomography and aortography revealed an ascending aortic aneurysm and contusion of the upper lobe of the right lung. Due to concerns about bleeding from the lung contusion, surgery was delayed for one week. During surgery, intimal tears were detected at two sites in the ascending aorta. The wall of the ascending aorta was subsequently resected and a prosthetic graft inserted. The postoperative period was uneventful and a postoperative aortogram showed that the graft had molded well.

Accidents, Traffic↗
PubMed1999

Successful surgical treatment of impending rupture of thoracoabdominal aortic aneurysm in an elderly patient with severe pulmonary emphysema.

In a case of successful surgery for impending thoracoabdominal aortic aneurysmic rupture, an 83-year-old man with severe pulmonary emphysema was transferred to our hospital diagnosed with impending aneurysmic rupture. The aneurysm had been pointed out 2.5 years ago but surgical repair was not undertaken due to the patient's severe pulmonary emphysema. After admission, computed tomography showed an enlarging saccular thoracoabdominal aortic aneurysm. Emergency surgery was conducted because of severe pain below the left costal margin. We resected the wall of the saccular aortic aneurysm and reconstructed the aorta with an on-lay patch under femoro-femoral bypass and selective visceral organ perfusion. Tracheostomy provided respiratory care on the day following surgery. The patient was weaned from respiratory support 6 days after surgery. Postoperative aortography showed that the reconstructed thoracoabdominal aorta functioned satisfactorily. The patient remains in good health 18 months after surgery.

Aged↗
PubMed1999

[Bacteriological studies of traveller's diarrhoea (6). Analysis of enteropathogenic bacteria at Kansai Airport Quarantine Station from September 4th, 1994 through December 1996].

During the period of investigation from Sept. 4, 1994 to Dec, 1996, a total of 11,446,534 overseas travellers were quarantined at Kansai Airport Quarantine Station, and 22,187 voluntarily reported of episodes suffering from diarrhoea. Bacteriological examination of the stools a total of 9,299 individuals' was performed, and the following results were obtained. 1) Various enteropathogenic bacteria were isolated from 33.3% of the stools examined. Bacterial species isolated were as follows: Plesiomonas shigelloides, 2,066 cases (66.7%); Vibrio parahaemolyticus, 358 cases (11.6%); Aeromonas sobria, 360 cases (11.6%); Shigella spp., 291 cases (9.4%); Salmonella spp., 183 cases (5.9%); A. hydrophila, 126 cases (4.1%); and V. cholerae non-O1, 121 cases (3.9%). However, ETEC was not done with an object of test. 2) In 502 cases (16.2%), plural enteropathogenic bacteria were isolated from single patient, suggesting high frequency of a mixed infections. 3) From Feb. to Mar. 1995, thirteen cases cholera were found from patients who had travelled to Bali, Indonesia. Cases with enteropathogenic bacteria other than V. cholerae O1 were found without any seasonal variation. 4) The major regions where the travellers were infected with the pathogens are as follows: Vibrio spp., were from only Asia; Shigella, widely distributed but especially in India and Indonesia; P. shigelloides and Salmonella, widely distributed. 5) Among the Shigella strains, S. sonnei were isolated the most, followed by S. flexneri, S. boydii and S. dysenteriae. A strain of S. boydii provisional serovar E 16553 was isolated from a patient infected in India. 6) Among the Salmonella serovars, Salmonella Enteritidis was isolated the most frequently (49 cases, 25.7%). 7) 265 (89.2%) of 297 Shigella strains, 52 (27.2%) of 19] Salmonella strains, and 19 (95.0%) of 20 V. cholerae O1 were resistant to one or more drugs tested (SM. CP. TC. KM. ABPC. NA. OFLX). 8) All of the 20 V. cholerae O1 strains were Ogawa, E1 Tor. All of them were toxigenic strains. 9) The most frequently isolated serovar of V. parahaemolyticus was O3: K6. 89.8% of all V. parahaemolyticus strains were positive for thermostable direct hemolysin (TDH) gene, and 14.6% of them were positive for TDH-related hemolysin (TRH) gene by DNA-probe or PCR method.

Asia, Southeastern↗
PubMed1999

[Proliferation inhibition of glioma cells by vitamin K2].

The antitumor effects of vitamin K2 were studied using three glioma cell lines: C6 (rat glioma cell), RBR17T and T98G (human glioma cell). The antitumor effects were estimated by count assay. The results was that vitamin K2 induced growth inhibition in a dose-dependent manner. The RBR 17T cells exposed to vitamin K2 for 72 hours resulted in oligonucleosomal DNA fragmentation and formed a ladder on agarose gel electrophoresis. Furthermore, the RBR17T cells exposed to vitamin K2 for 24 hours were significantly accumulated in the G0G1 phase of the cell cycle. Those results suggested that vitamin K2 can inhibit the proliferation of cells through the induction of cell cycle arrest and apoptosis for tumor cells. The combined treatment of vitamin K2 with ACNU or 5-FU or INF-beta or 1,25-dihydroxyvitamin D3 enhanced growth inhibition significantly. In conclusion, vitamin K2 can be a useful drug for the treatment of glioma.

Animals↗
PubMed1999

A new devised skirted elephant trunk technique.

A simple and effective new elephant trunk technique was devised and applied to two patients with a successful result. In advance before the operation, an arch graft with a skirted elephant trunk was made. This was done by inserting a smaller, 22 mm diameter sized graft into the arch graft at the distal end and suturing it so as to leave a skirt extending over the smaller graft. This configuration facilitates the distal anastomosis and effectively shortens anastomotic time.

Adult↗
PubMed1999

Two-stage operation for multiple aneurysms of the thoracic aorta, abdominal aorta, and left common iliac artery in an octogenarian.

Multiple aortic aneurysms are well described in the surgical literature. However, there are many problems related to surgical treatment of elderly patients with such aneurysms. This report presents the case, an octogenarian with multiple aortic aneurysms that were successfully treated by graft replacement. An 82-year-old man with a descending aortic aneurysm was referred to our institution for surgery. In addition to the previously diagnosed aneurysm, computed tomography and aortography showed an abdominal aortic aneurysm and a left common iliac aneurysm. Since the patient was an elderly man with chronic obstructive pulmonary disease, a two-stage operation was performed. The abdominal aortic aneurysm and left common iliac aneurysm were resected first due to the risk of thromboembolism from the abdominal aortic aneurysm during surgery involving replacement of the descending aorta under femoro-femoral (F-F) bypass. Fifty-two days after the first operation, a second operation was performed to repair the descending aortic aneurysm. The postoperative course was uneventful. Angiography after the operation showed satisfactory replacement of the multiple aortic aneurysms. The patient was discharged 25 days after the second operation.

Aged↗
PubMed1999

Reversible peritoneal calcification in a patient treated by CAPD.

The patient, a female, aged 65 years, developed diffuse peritoneal calcification nine years after commencing CAPD therapy. No abdominal symptoms or evidence of peritonitis were discovered during this period. Before peritoneal calcification was detected, a dialysate with a high glucose concentration (3.86%) had been used once daily for 16 months. In the case of this patient, it was not possible to discover any of the previous indicated etiologies of peritoneal calcification such as significantly elevated values for the product Ca x P, overt secondary hyperparathyroidism, or relapsing peritonitis. It was realized that the use of a high-glucose dialysate in a patient on long-term CAPD treatment had been one causative factor. After peritoneal calcification had been confirmed, the calcium concentration of the dialysate changed from 3.5 mEq/l to 2.5 mEq/l and the patient was put on a regime of 2.0 g alumigel (aluminum-containing phosphate binders) a day. Eight months later, a CT scan was taken. The peritoneal calcification has clearly been mitigated. At present, CAPD therapy is being continued in the absence of any abdominal symptoms.

Aged↗
PubMed1998

Successful treatment of bilateral deep femoral aneurysms and multiple iliac aneurysms associated with severe aortic valve disease: report of a case.

We report herein the case of a patient in whom aneurysms of the bilateral deep femoral arteries (DFA) and multiple iliac aneurysms associated with severe aortic valve disease were successfully treated by a two-staged operation. The patient was a 74-year-old man who had dense calcification of the ascending aorta and aortic arch. Prior to aortic valve replacement (AVR), the aneurysms of the DFA and internal iliac arteries were resected. The terminal end of the abdominal aorta and bilateral common iliac arteries were then reconstructed with a Y graft to be used as a possible alternative arterial input route in place of the ascending aorta for extracorporeal circulation during the AVR. The inferior mesenteric artery (IMA) was well developed, and the external iliac arteries and their branches were preserved at aneurysmectomy. Postoperatively, there was no ischemia of the pelvic organs or the hip muscles. The AVR was subsequently performed 5 weeks after the first operation, and the patient was discharged after an uneventful postoperative course.

Aged↗
PubMed1998

Improvement in esophageal varices and liver histology postoperatively in Budd-Chiari syndrome.

BACKGROUND: In the past 17 years, 32 patients with Budd-Chiari syndrome were treated by reconstruction of the occluded inferior vena cava and reopening of the hepatic veins under femoro-femoral normothermic extracorporeal partial bypass. The mean follow-up was 8 years (range, 1.5 to 17 years). METHODS: To evaluate the benefits of our operative procedure, we compared the preoperative, early postoperative, and late postoperative endoscopic appearance of the esophageal varices and the histologic findings of the liver tissue obtained intraoperatively and at a later date. RESULTS: The esophageal varices found preoperatively in 29 patients (90.6%) had disappeared in 7 patients by the time of discharge, and in 2 patients they disappeared 4 to 7 years after surgery. In the remaining 20 patients, the grade of the esophageal varices was reduced markedly. Histologic examination of the liver showed cirrhosis in 22 patients, fibrosis in 9 patients, and severe congestion in 1 patient. Inspection of the liver in the late postoperative period (in 10 patients) showed improvement in centrilobular congestion and no increase in interlobular fibrosis. CONCLUSIONS: Gradual and steady improvement of esophageal varices and hepatic fibrosis can be achieved after our operative procedure.

Adult↗
PubMed1998

A ruptured syphilitic descending thoracic aortic aneurysm. The characteristic findings on computed tomography for the etiological diagnosis of aneurysm.

We report the case of a 72-year-old man with a ruptured syphilitic descending thoracic aneurysm who underwent an emergency operation and successful graft replacement. Preoperative physical examination showed a pulsative mass on the left back. Preoperative computed tomography showed bone destruction in the TH6 to TH10 thoracic vertebrae and ribs and penetration (or rupture) of the aneurysm into the subcutaneous tissue. During the period of preoperative evaluations, free wall rupture of the aneurysm occurred and emergency operation for graft replacement was performed. The microscopical examination of the aneurysmal wall revealed the syphilitic changes. In literature, the vertebral destruction by atherosclerotic aneurysm is usually located at the TH12 to L3 of vertebral bodies. From the findings of this patient and a study of existing literature, we concluded that the finding of vertebral bone beyond TH12 to L3 region on CT examination of the aneurysm could be a etiological characteristic finding for syphilitic aortic aneurysm.

Aged↗
PubMed1997

Quantitative evaluation of blood flow distribution to exercising and resting skeletal muscles in patients with cardiac dysfunction using whole-body thallium-201 scintigraphy.

BACKGROUND AND HYPOTHESIS: Decreased blood flow to working muscles makes an important contribution to exercise intolerance in patients with chronic heart failure. This study was undertaken to examine whether maldistribution of skeletal muscle blood flow is closely related to exercise intolerance in patients with cardiac dysfunction. METHODS: Whole-body thallium scintigraphy was performed during one-leg exercise in 11 patients with left ventricular (LV) dysfunction (LV ejection fraction < 45%). Blood flow distribution to the exercising and resting legs was quantified by expressing regional thallium counts as a percentage of the whole-body counts at rest, at the level of anaerobic threshold, and at peak exercise. RESULTS: At anaerobic threshold, the thallium activity of exercising muscle increased from 4.2 +/- 0.7 to 14.0 +/- 2.5% (p < 0.05) in the thigh and from 1.7 +/- 0.3 to 4.1 +/- 0.9% (p < 0.05) in the calf, compared with the resting value. Consequently, the ratio of thallium activity between exercising and resting legs increased to 2.7 +/- 0.7 (p < 0.05) in the thigh and to 2.3 +/- 0.7 (p < 0.05) in the calf. When plotted as a function of anaerobic threshold, thallium activity of the exercising thigh (r = 0.78, p < 0.05) and the thallium ratio between exercising and resting thigh (r = 0.69, p < 0.05) declined with the reduction of exercise tolerance. These correlations were not observed in calves. CONCLUSION: Whole-body thallium scintigraphy demonstrated a maldistribution of leg blood flow in patients with reduced aerobic exercise capacity, suggesting that this abnormality could play an important role in exercising intolerance in these patients.

Adult↗