Biomedical subjects
Publications and source records attributed to T Mitsui.
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Q10 values of the protein phosphatases that can dephosphorylate the regulatory light chain of smooth muscle myosin were determined. Six phosphatases were examined, i.e. skeletal muscle protein phosphatase 1c; protein phosphatase 2Ac; smooth muscle phosphatases (SMP) I, II, and IV; and myosin-associated protein phosphatase (MAP phosphatase). Among them, SMP-IV and MAP phosphatase, which can dephosphorylate intact smooth muscle myosin, showed extremely high Q10 values (5.3 and 5.2, respectively). On the other hand, the Q10 values of other tested phosphatases were within the range of the normal enzyme reaction (Q10 = 2.0). The rate of dephosphorylation of the myosin light chain in alpha-toxin-skinned strips was measured at different temperatures. The results provided a Q10 of 5.1, which was quite similar to those values obtained for SMP-IV and MAP phosphatase. These results suggest that the physiological myosin light chain phosphatases are SMP-IV and/or MAP phosphatase, i.e. type 1 protein phosphatases. The temperature dependence of maximum force, the steady-state extent of myosin light chain phosphorylation, and the relaxation rate of alpha-toxin-permeabilized rabbit portal vein smooth muscle strips were measured. Both maximum force and the extent of myosin light chain phosphorylation were significantly higher at lower temperature (15 degrees C) than at higher temperature (25 degrees C) under all pCa conditions tested, i.e. > 8, 6.3, and 5. The temperature dependence of the relaxation rate was much steeper (decreased 4 times by lowering the temperature from 25 to 15 degrees C) than that of the initial rate of increase in force development (decreased 1.4 times by lowering the temperature from 25 to 15 degrees C). These results are consistent with the Q10 values of myosin light chain phosphatases (Q10 = 5) and myosin light chain kinase (Q10 = 1.7) and further show that the smooth muscle type 1 phosphatases are responsible for the dephosphorylation of smooth muscle myosin in situ.
The aims of this study are to evaluate the diagnostic ability of chest computed tomography (CT) in the early detection of pleural disease and to analyze the results of surgical treatment for lung cancer with pleural dissemination. Twenty-three non-small cell lung cancer patients with pleural dissemination, but without distant metastasis, underwent pleuropulmonary resection during the past 15 years. Chest CT scans were obtained preoperatively in 21 of those patients. In eight patients without pleural effusion, small pleural nodules, about 3-5 mm in size, were found in their chest CT. However, during surgery, small nodules were more frequently observed on the parietal pleura than on the visceral pleura in five of them. Therefore, early detection of the dissemination by chest CT seemed limited to only those of the visceral pleura. In the survival curve after resection, there was no difference among the patients with n2 disease, but there was a significant difference between the patients without n2 disease and those with it (P < 0.05). The presence of n2 disease appeared to be a poor prognostic sign in this form of advanced lung cancer.
Expression of the myoglobin (Mb) gene in skeletal muscle was studied in patients with Duchenne muscular dystrophy (DMD), polymyositis (PM), or amyotrophic lateral sclerosis (ALS) by measuring Mb concentration by radioimmunoassay and Mb messenger ribonucleic acid (RNA) (MbmRNA) levels by Northern blot analysis. Mb concentrations in the muscle cells (Mb/noncollagenous protein) were decreased in patients with DMD, PM, or ALS. However, while Mb concentrations per MbmRNA content (Mb/MbmRNA) were decreased in DMD and PM patients, these values were normal in ALS patients. These results suggest that Mb synthesis is increased in muscles of DMD and PM patients, but is not sufficient to compensate for the excessive loss of Mb from the affected muscles, and that the synthesis is decreased in the muscles of ALS patients.
The intracellular localization of myoglobin mRNA in the skeletal muscles of normal subjects was examined by in situ hybridization using a biotin-labeled cDNA probe. By phase-contrast microscopy, myoglobin mRNA signals were demonstrated to be located preferentially on the A-band. Two different methods of tissue preparation, i.e., pre-embedding method and post-embedding method, were used for the electron microscopic study. With the pre-embedding method, only a few gold particles were found to be associated with cytoskeletal filaments in the intermyofibrillar space. With the post-embedding method, superior preservation of sections and higher signal intensities were obtained. Although most of the gold particles were localized on the A-band, some were seen in other regions; i.e., in the intermyofibrillar space, perinuclear space, or the I-band, where myoglobin is localized. These findings suggest that myoglobin is primarily synthesized on the A-band, where ribosomes predominantly exist, although myoglobin is also localized on the I-band. The predominant localization of myoglobin mRNA on the A-band may aid in the mRNA transcription and may be related to the regulation of myoglobin synthesis in skeletal muscle cells.
Four patients who developed intractable supraventricular tachycardia (SVT) after open heart surgery were treated using a new therapeutic method of creating a pharmacological atrioventricular block by the continuous infusion of verapamil with ventricular pacing. Both the initial dose and the effective dose, being the verapamil dose necessary to maintain pharmacological atrioventricular block to prevent the recurrence of SVT, were surveyed with clinical results. The verapamil-induced hemodynamic changes observed 4 h and 8 h after treatment, as indicated by systolic arterial blood pressure, mean arteral blood pressure, heart rate, cardiac index, and urine volume, were compared with the values 1 h before treatment. After an initial low dose infusion of 0.07 +/- 0.02 mg/kg.h had been given, an effective and safe dose of 0.11 +/- 0.05 mg/kg.h was determined. Good hemodynamic and clinical results were achieved in all four patients who are now leading an active life. These results therefore encourage us to apply this therapeutic method for treating patients with intractable and recurrent SVT after open heart surgery.
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Two siblings who exhibited hereditary parkinsonism with pyramidal signs and cerebellar ataxia are reported. Anticholinergics had a dramatic beneficial effect in both cases, but levodopa did not. This responsiveness, which is similar to that reported in patients with Joseph's disease, suggests dysfunction of an "indirect pathway" involving the globus pallidus and the subthalamic nucleus, in addition to that of the nigrostriatal system. We propose a new hereditary variant of early onset Parkinson's disease distinct from the levodopa sensitive forms of juvenile Parkinson's disease.
Activation-associated antigens such as CD11b, CD14 and CD64 of neutrophils have been reported. Although CD48 is an activation antigen of lymphocytes and monocytes, whether it is an activation antigen of neutrophils has not previously been examined. Herein, using FACS analysis, we examined the expression of surface CD48 on neutrophils activated in vivo by G-CSF administered for the treatment of idiopathic aplastic anemia. CD48 expression was increased 24 h after the initial G-CSF infusion and peaked within 1 week. Within a few days after discontinuation of G-CSF administration, it returned to the pretreatment level. This indicates that CD48 is an activation antigen of neutrophils.
A 76-year-old woman with abdominal aortic aneurysm was referred to our hospital with a complaint of abdominal pulsatile mass. CT and angiogram revealed infrarenal abdominal aortic aneurysm (AAA) with right common iliac aneurysm. AAA was replaced with the bifurcated Dacron graft and iliac aneurysm was resected concomitantly. A focal perforation of intima and medial wall hematoma were found in the iliac aneurysm. These findings corresponded with penetrating atherosclerotic ulcer (PAU). PAU in the abdominal aorta may form the abdominal aortic false aneurysm, and may cause the rupture of aneurysm. It is an critical sign of "aortic catastrophe".
Prosthetic valve thrombosis is associated with high mortality. Thrombolytic therapy is a promising alternative to valve replacement in the management of prosthetic valve thrombosis. To determine the efficacy and safety of thrombolytic therapy for thrombosed Björk-Shiley aortic valve prosthesis, 4 patients who received urokinase intravenously for this disorder were analyzed. In 3 patients, the successful outcome was sustained in that they remained asymptomatic and did not require operative intervention during follow-up, which ranged from 17 to 101 months. In one patient clinical signs of mild congestive heart failure occurred. This patient was surgically treated by thrombectomy and debridement of the prosthetic valve. Failure of urokinase treatment to resolve the thrombus after 1 week indicates that tissue overgrowth or fibrous, organized thrombus is the cause of prosthetic malfunction. Surgical intervention for this problem should be considered only after thrombolytic therapy has been tried and has failed. Our experience with urokinase treatment of thrombosis of aortic Björk-shiley prostheses indicates that this form of treatment should always be applied before surgical intervention. We also attempted to define the optimum protocol of fibrinolytic therapy by clinical evaluation. A protocol for the safe treatment of thrombosed valve is urokinase in initially administered in the doses as 960,000 units for 24 hours, then followed by a maintenance infusion at the half dose every 24 or 48 hours later. Thrombolytic therapy should be continued for 1 week at least to prevent rethrombosis even normalization of valve function was documented clinically. Simultaneous heparin infusion of 10,000 units for 24 hours is then started to replaced by warfarin treatment adjusted to obtain optimal prothrombin times.(ABSTRACT TRUNCATED AT 250 WORDS)
Accurate repair of postinfarction ventricular septal perforation (VSP) has mainly depended on the technique for friable septal reinforcement. Modified closure of VSP with Xenomedica patch was performed in 63-year-old male. Friable border of the septum was successfully sandwiched between horse-shoe shape prejett (right side) and main patch (left side). The advantages of this modified surgical procedure are as follows: (1) septum can be seen through horse-shoe shape patch (even when tying the mattress sutures; (2) Xenomedica patch is flexible enough for avoiding the cutting for friable septum, and is strong enough for sandwiching the septum.
A 59-year-old man underwent CABG with left internal thoracic artery (LITA) to the first diagonal branch and saphenous vein graft (SVG) to the right coronary artery (RCA). Pump off was quite uneventful, but re-anastomosis was done because bypass graft flow measured before the closure of chest was 6 ml/min, which was most likely due to sclerotic right coronary artery and technical error. After re-anastomosis, bypass flow of SVG to RCA was measured 95 ml/min. Root mean square total (RMST) immediately after aortic declamp for the first time was 39% compared with that measured prior to operation, but improved to 49% after aortic declamp at the second time. It recovered to 127% 2 days after operation, and 137% at 7th postoperative day. RMST indicates the total electropotential per unit time from the beginning to the end of QRS. It has the specificity to predict VT and postoperative pump failure. In this case, it is suspected that RMST may be a predictor that revascularization would be complete or incomplete in operations for ischemic heart disease.
Changes of serum ionized calcium concentration (Ca2+) during cardiopulmonary bypass (CPB) were analyzed in 30 pediatric cardiac patients less than 15 kg body weight. Ca2+ decreased suddenly after the start of CPB, and it gradually increased to the normal value. Citrate added to the stored blood for priming and its metabolism might play a role in these changes of Ca2+. Addition of adequate volume of calcium chloride to the priming prevented sudden decrease of Ca2+. Although addition of citrate before aortic declamp effectively decreased Ca2+ and may prevent reperfusion cardiac injury associated with hypercalcemia, there were no correlation between predeclamp level of Ca2+ and serum CPK and GOT levels.
Coronary artery bypass grafting (CABG) was performed using saphenous vein grafts anastomosed in reversed Y-shaped in two patients because of the atherosclerotic ascending aorta. Postoperative course was uneventful, however, the common part of reversed Y-shaped grafts was occluded in both patients within two years after operations. The arms of reversed Y-shaped grafts were patent, and played a role of major collateral between LAD and RCA. They were treated successfully with reoperation in one patient and PTCA in another.