Biomedical subjects

T Misaki

Publications and source records attributed to T Misaki.

At least 127 records · Page 7Linked to original sources

PubMed1994

Scintigraphic findings of the thyroid in hypothyroid patients with blocking-type TSH-receptor antibodies.

The present study was designed to analyse the scintigraphic appearance of the thyroid in hypothyroid patients with blocking-type TSH receptor antibodies (TRAbs). Eleven hypothyroid patients with autoimmune thyroiditis positive for TSH binding inhibitor immunoglobulins (TBII) [80% +/- 12 (SD)%; normal < 11%] and for thyroid stimulation-blocking antibodies (TSBAbs) (90% +/- 9%: normal < 32%) were studied. Thyroid scanning was performed using technetium-99m or iodine-123, when the patients were hypothyroid. Analysis of the scan images revealed the presence of localized functioning areas in six patients (group 1), and no visualization of the thyroid in the remaining five patients (group 2). Patients in group 1 showed significantly higher uptake of 99mTc than those in group 2 (P < 0.05). Interestingly, three patients in group 1 were positive for thyroid-stimulating antibodies (TSAbs) (249% +/- 17%; normal < 145%), which were not detected in the remaining eight patients. Antibodies against thyroglobulin and microsomal antigens were detected in nine nine (81.8%) and 11 (100%) patients, respectively, but neither of these titres correlated with the scan image. Three patients in group 1 underwent scintigraphy again after treatment with thyroxine, at which time the functioning lesion was not noted. Fourteen hypothyroid patients with negative TBII displayed no such scintigraphic findings. Chronic stimulation of the thyroid by TSAbs and/or TSH might be responsible for the presence of the functioning lesion, but clarification of the mechanism requires further studies. In summary (1) TSAbs were detected in three (27.3%) of 11 hypothyroid patients with blocking TRAbs; (2) thyroid scintigraphy revealed the presence of localized functioning area(s) in approximately half of these cases.

Adolescent↗

PubMed1994

Omental transfer for the treatment of sternal infection after cardiac surgery: report of three cases.

Sternal infection is an uncommon but serious complication following cardiac surgery. We report herein three cases of postoperative sternal osteomyelitis successfully treated by omental transfer. Two patients had undergone valve surgery and the other underwent division of an accessory pathway for Wolff-Parkinson-White syndrome. Gram-positive organisms were identified in cultures of the exudate in all three patients, as Staphylococcus epidermidis in two and Methicillin-resistant Staphylococcus aureus in one, and concomitant mediastinitis was demonstrated by computed tomography in two cases. Each patient initially underwent sternal debridement and closed irrigation with 0.5% povidone-iodine solution, following which the cultured exudate from two of the patients was negative. The omentum was transferred in two of the patients because they had poor granulation tissue and in the third patient to fill a large dead space, and the postoperative course was uneventful in all three patients. Thus, we conclude that omental transfer is a useful technique for the treatment of postoperative sternal osteomyelitis.

Adolescent↗

PubMed1994

Reconstruction with free jejunal autograft after pharyngolaryngoesophagectomy.

Twenty-four patients with hypopharyngeal or cervical esophageal carcinoma were treated surgically. All had squamous cell carcinoma, and none had intrathoracic lymph node involvement by preoperative computed tomography. Endoscopy in 18 patients confirmed there was no intramural spread into the thoracic esophagus. The patients underwent pharyngolaryngoesophagectomy and bilateral modified radical neck dissection. Reconstruction of the cervical esophagus was performed with transplantation of a free jejunal autograft. Postoperative complications included anastomotic leak in 2 patients (8.3%), wound infection in 3 (12.5%), and intussusception in 4 (16.7%). Reconstruction of the cervical esophagus was successful in 23 (95.8%) of the 24 patients. The operative mortality rate was 4.2%, and the 5-year survival rate was 39.7%. We emphasize that pharyngolaryngoesophagectomy followed by transplantation of a free jejunal graft is suitable for cervical esophageal carcinoma or hypopharyngeal carcinoma when the disease is limited to the cervical region.

Adult↗

PubMed1994

Development of a new intraoperative radiofrequency ablation technique using a needle electrode.

We studied a new intraoperative technique for radiofrequency ablation using a needle electrode. The ventricles of 12 mongrel dogs were ablated. The needle electrode was inserted to a depth of 3 mm through the epicardium. Macroscopically, tissue defect was found only at the needle insertion site. The degenerated area had a well-demarcated bullet shape with microscopical coagulation necrosis. This characteristic shape allows the ablation of deeper areas of the myocardium by deeper insertion of the ablation needle. Compared with conventional epicardial surface ablation, this new method could be used to achieve deeper coagulation. For any given energy level and conductance, the ratio between the volume and the depth of the lesion with this new method is smaller than that of lesions made by the conventional radiofrequency ablation method. With this new method, the energy spreads vertically, a characteristic suitable for deep ablation. This may result from the shape of the needle electrode itself. For ablation of deep targets, this new method is superior to the conventional approach because less myocardium is coagulated and the target can be ablated with greater efficiency, requiring the destruction of less tissue. In conclusion, the needle electrode procedure can achieve a narrower ablation for deeper targets than can the conventional technique.

Animals↗

PubMed1994

Internal thoracic artery graft holder for coronary artery bypass grafting.

An internal thoracic artery graft holder, designed for use during coronary artery bypass grafting, is described. This new holder is atraumatic and holds the internal thoracic artery graft securely during anastomosis. The use of this instrument facilitates the use of an arterial graft for coronary artery bypass grafting.

Coronary Artery Bypass↗

PubMed1994

Surgical treatment of Wolff-Parkinson-White syndrome in infants and children.

Electrophysiologic features and surgical results were examined in 55 pediatric patients who underwent surgical accessory pathway division for Wolff-Parkinson-White syndrome. There were 31 male and 24 female patients ranging in age from 4 months to 15 years (mean age, 9.8 +/- 4.2 years; 25 patients were less than 10 years old; 4 patients were less than 12 months). Eleven of these patients had associated congenital heart disease and underwent concomitant surgical procedures to treat those conditions. Preoperative effective refractory period of antegrade accessory pathways, the right atrium, atrioventricular node, and cycle length during reentrant tachycardia were shorter in pediatric patients than in adult patients. Antegrade accessory pathways showed right predominance more frequently in the pediatric group than in the adult group. Surgical techniques included an endocardial approach (an epicardial approach was used in 1 patient) and concomitant operation for combined heart disease. The early mortality rate was 3.6%, whereas no late deaths occurred during the follow-up period of 96.8 +/- 54.9 months (maximum follow-up, 205 months). The absolute cure rate was 92%. There were no significant differences in early and late mortality between pediatric and adult patients. Surgical treatment of the Wolff-Parkinson-White syndrome in pediatric patients is as safe and effective as in adults. Considering the potential complications from prolonged fluoroscopic exposure during catheter ablation, surgical division of accessory pathways in children is a promising modality for the treatment of Wolff-Parkinson-White syndrome in selected cases.

Adolescent↗

PubMed1994

Surgical treatment of arrhythmogenic right ventricular dysplasia: long-term outcome.

Eight male patients ranging from 15 to 51 years old (mean age, 36.3 years) underwent surgical treatment of ventricular tachycardia (VT) associated with arrhythmogenic right ventricular dysplasia. One patient had an associated left ventricular aneurysm. The earliest activation site was detected for 15 lesions, and delayed potentials were recorded during sinus rhythm in all patients. On the basis of the epicardial mapping, the origins of the VT foci in the right ventricle were resected. Cryoablation on the surrounding myocardium was performed. There were no surgical deaths or postoperative fatal complications. During long-term follow-up, there has been no recurrence of VT and no congestive heart failure in the 6 patients without left ventricular involvement. The 2 patients with LV involvement died late of either congestive heart failure or development of VT originating from the left ventricle. In conclusion, a surgical approach consisting of myocardial excision and cryocoagulation offers a curative treatment of VT associated with arrhythmogenic right ventricular dysplasia and yields excellent long-term results when the VT origin is well identified in the right ventricle.

Adolescent↗

PubMed1994

Stimulated iodide uptake in FRTL-5 cells preincubated with Graves' immunoglobulins in NaCl-free medium: a sensitive assay for thyroid-stimulating antibodies.

The present study was designed to increase the sensitivity of iodide uptake assay for detecting thyroid-stimulating antibodies (TSAb). Based on the previous observations that TSAb are more active to increase cAMP levels in the NaCl-free condition, we improved the assay procedure and defined the optimum conditions: FRTL-5 cells were incubated with immunoglobulin (IgG) in NaCl-free medium for 3 days, and then 125I uptake in the cells was determined after 60 min. The sensitivity of iodide uptake assay for TSAb increased 3-fold by the modification, when assessed by the IgG concentration required to elicit the same response. The described assay is as sensitive as that using cAMP measurement in NaCl-free buffer. Thus, it could detect TSAb in all 21 patients with active Graves' disease and in 7 of 8 with ophthalmic Graves' disease but not in 29 of 30 control subjects. Thyroid stimulating activities assessed by these two assays correlated with each other (n = 29, r = 0.707, p < 0.001). False positive results obtained in 4 hypothyroid patients with Hashimoto's thyroiditis (serum TSH concentrations, 11-171 mU/L) could be prevented using anti-TSH antibodies. In summary, the described assay allows evaluation of stimulated thyroid function directly without affecting the detection of TSAb.

Animals↗

PubMed1994

Therapy of Graves' ophthalmopathy with intravenous high-dose steroid followed by orbital irradiation.

We investigated the effects of intravenous high-dose steroid therapy followed by orbital irradiation for Graves' ophthalmopathy in eight patients. All patients presented with diplopia or fixed globes. Extraocular muscle dysfunction showed excellent improvement after the combined therapy; diplopia disappeared completely in five of them, and one patient with fixed globes showed normal eye movement. Two other patients also exhibited great improvement, although their diplopia persisted. Their ophthalmopathy index was decreased from (mean +/- SD) 4.25 +/- 0.82 to 0.75 +/- 1.48. Extraocular muscle enlargement, assessed by magnetic resonance imaging study after the radiotherapy, was also reduced after the combined therapy, although two patients did not show remarkable enlarged extraocular muscles. There was no change in extraocular muscle thickness 6-9 months after the therapy, and the ophthalmopathy index did not show change in a long follow-up (maximum 37 months after the therapy). These results suggest that high-dose methylprednisolone followed by orbital radiotherapy is a good therapeutic design for Graves' ophthalmopathy and justify a prospective randomized trial.

Adult↗

PubMed1994

Induction in vitro of 72-kD heat shock protein in a continuous culture of rat thyroid cells, FRTL5.

In Graves' disease and Hashimoto's thyroiditis, the presence of 72-kD heat shock protein (hsp-72) on thyrocytes has been reported. To clarify the significance of this phenomenon, we induced the antigen in thyroid cell culture in vitro. In the FRTL5 rat cell line, which had been heated at 42.5 degrees C or treated with sodium arsenite, expression of hsp-72 was examined with immunoperoxidase staining and immunoprecipitation of the metabolically labelled protein using a specific MoAb. In the cells cultured either with or without thyrotropin (TSH), heat and chemical stresses reproducibly and dose-dependently induced hsp-72 antigen, whereas unstimulated controls had no significant immunoreactivity. Unlike in Graves' retrocular fibroblasts, hydrogen peroxide was not an effective stress in FRTL5, and the induction was not suppressed by methylmercaptoimmidazole and propylthiouracil, nor enhanced by interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha). These data could not support the hypotheses that suppression of thyroid autoimmunity by thionamides is due to their modulatory action on hsp-72 expression, or that presence of that antigen in the thyroid tissues affected by autoimmunity is secondary to cytokine secretion from infiltrating immunocytes. On the other hand, coculture experiments of stressed FRTL5 cells and syngeneic Fisher rat splenocytes suggest that aberrantly expressed hsp may activate part of the thyroid-infiltrating lymphocytes and thereby aggravate autoimmune processes. The induction and detection systems of hsp-72 using FRTL5 cells would facilitate future studies, possibly utilizing human materials as well, to explore possible relations between stress proteins and thyroid autoimmunity.

Animals↗

PubMed1994

Metastatic thyroid cancer presenting as thyrotoxicosis: report of three cases.

Three patients with metastatic thyroid follicular carcinoma developed thyrotoxicosis. Two had mild T3 toxicosis without detectable TSH binding inhibitor immunoglobulins (TBII) or thyroid stimulating antibodies (TSAb). Considerable concentration of 131I by tumours occurred, although serum TSH was undetectable. The third patient developed thyrotoxicosis several months after treatment with 131I had commenced and this was associated with concurrent increase in both TBII (90%; normal, less than 11%) and TSAb (2100%). We conclude that thyrotoxicosis in patients with metastatic thyroid carcinoma may result from a large bulk of tumour functioning either autonomously or after stimulation by TSH receptor antibodies.

Adenocarcinoma, Follicular↗

PubMed1994

Myocardial coagulation by intraoperative Nd:YAG laser ablation and its dependence on blood perfusion.

To investigate whether the efficacy of intraoperative laser ablation therapy is affected by myocardial blood perfusion, we irradiated 11 canine hearts through the epicardium with a Nd:YAG laser (10, 20, and 30 J/mm2) using air as the medium. Compared coagulated myocardial depth, width, and volume obtained in the red beating heart was compared with those in the white nonbeating heart infused with 0 degrees C saline (cardioplegic model) via the coronary artery. Histologically, the macro- and microscopical findings were very similar. At each level of energy, the width and volume of red myocardium coagulated were significantly larger than those of white myocardium (P < 0.01). At 30 J/mm2, the depth of coagulation of red myocardium was significantly larger than that of white myocardium (P < 0.01). The coagulated volume of the white myocardium was about 60% of that of the red myocardium. Nd:YAG laser energy was absorbed by blood (red color = hemoglobin), and more energy was transferred in the higher temperature myocardium. During intraoperative Nd:YAG laser ablation, the presence of blood perfusion in cardiac tissue is thought to be an important factor affecting safe irradiation.

Animals↗

PubMed1994

Surgical treatment of ventricular tachycardia after surgical repair of tetralogy of Fallot. Relation between intraoperative mapping and histological findings.

BACKGROUND: The mechanism of ventricular tachycardia (VT) after correction of tetralogy of Fallot (TF) is poorly understood. The purpose of this study was to examine the histopathology of the arrhythmogenic area detected by intraoperative mapping. METHODS AND RESULTS: The patients were three men who underwent radical surgery for TF at age 3, 3, or 5 years, respectively. VT developed at 8, 9, or 11 years, respectively, after surgery, and shock developed during VT in every case. The ECG revealed monomorphic VT in two cases and polymorphic VT in one case. Induction of VT resulted in a wide left-axis deviation-pattern QRS with cycle lengths varying between 260 and 330 milliseconds. The VT origin was identified at the right ventricular outflow tract (RVOT). A radical operation was performed with the patient under cardiopulmonary bypass. On epicardial mapping, delayed activation of the RVOT was recorded during sinus rhythm, and clockwise circus movement of the macroreentry current during VT on the right ventricular free wall was documented in each case. The VTs were treated successfully by surgical resection and cryoablation of the myocardium. In every patient, histology of the myocardial specimens showed degeneration, adiposis, fibrosis, inflammatory cell infiltration, and scattered myocyte islets. These lesions corresponded anatomically to the area of myocardium in which delayed activation was evident during epicardial mapping. CONCLUSIONS: The results of this study indicate that patients with VT after radical correction of the TF have abnormal histopathological findings at the site of the prior right ventriculotomy scar. These lesions were noted within the region of delayed activation found during epicardial mapping and were found to be a part of the reentrant circuit.

Adult↗

PubMed1994

[A new one-step, labeled-antibody assay for measuring free thyroid hormone concentrations].

We describe one-step labeled-antibody assays for measuring free T4 and free T3 concentrations in serum, based on a novel principle (Amerlex-MAB). Free T4 or free T3 in the sample competes with a molar excess of a cross-reactant (T3 or T2, respectively), chemically coupled to magnetizable polymer particles, for binding to 125I-labeled monoclonal anti-T4 or anti-T3 antibody, respectively. 125I radioactivity bound to the solid phase is inversely proportional to the serum free T4 or free T3 concentration. This one-step assay apparently proceeds to equilibrium after 30 min at 37 degrees C. Within- and between-assay precision (CV) was < 5.7% for free T4 or 6.2% for free T3. The reference range was between 0.98 and 1.77 ng/100 ml for free T4 and between 2.8 and 4.6 pg/ml for free T3. The measurement of free T4 and free T3 concentrations could clearly discriminate hyperthyroid and hypothyroid patients from euthyroid subjects. These values correlated closely to those obtained by an analog radioimmunoassay (Amerlex-M). This method is free from interference by major T4-binding proteins in serum, showing improved performance, compared to the analog radioimmunoassay, with sera from NTI patients with low serum albumin concentrations or anti-thyroid hormone antibodies. We expect these assays to be clinically useful for the evaluation of thyroid functions.

Antibodies, Monoclonal↗

PubMed1994