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Biomedical subjects

S Komatsu

Publications and source records attributed to S Komatsu.

At least 109 records · Page 6Linked to original sources
PubMed1996

Mitosis-specific phosphorylation of smooth muscle regulatory light chain of myosin II at Ser-1 and/or -2 and Thr-9 in sea urchin egg extract.

We analyzed the kinase activities capable of phosphorylating the regulatory light chain of myosin-II (MRLC) from chicken gizzard in unfertilized and fertilized sea urchin egg extracts. Total kinase activity phosphorylating MRLC in vitro did not fluctuate throughout the first cell cycle. Phosphopeptide mapping analysis showed that MRLC was phosphorylated at two different sites corresponding to myosin light chain purified from chicken gizzard (MLCK) and protein kinase C (PKC) phosphorylation sites, namely MLCK and PKC sites, respectively. The activity of the kinase(s) responsible for phosphorylation of MRLC at PKC sites showed a significant increase at metaphase. Phosphoamino acid analysis revealed that this increase in MRLC phosphorylation was due to phosphorylation at serine residue (Ser-1 and/or Ser-2) and a threonine residue (Thr-9). This increase in phosphorylation at PKC sites is occurred concomitantly with an increase in histone H1 kinase activity. In contrast, MRLC phosphorylation at MLCK sites showed no significant changes during the first cell cycle. Butyrolactone I, a selective inhibitor of p34cdc2 kinase, inhibited the activity of the kinase(s) responsible for phosphorylation of MRLC at PKC sites at metaphase. These results suggest that the increase in MRLC phosphorylation at PKC sites (Ser-1 and/or -2, and Thr-9) at metaphase may be induced by p34cdc2 kinase. Thus, p34cdc2 kinase may be involved in the regulation of MRLC phosphorylation during cell division.

4-Butyrolactone↗
PubMed1996

Epidermal growth factor binding proteins in rice (Oryza sativa L.) leaves.

A ligand blotting experiment using [125I]epidermal growth factor (EGF) showed that there are EGF binding proteins in rice leaves. EGF binding proteins have isoelectric points and relative molecular masses of 5.5/35 kDa, 7.5/50 kDa and 8.3/40 kDa, respectively. The amino acid sequences of the N-terminal and internal regions of the EGF binding proteins were determined. The amino acid sequences of 35 kDa protein and 40 kDa were found to be homologous with those of the photosystem II oxygen-evolving complex. The amino acid sequence of the 50 kDa protein was homologous with that of riburose bisphosphate carboxylase/oxygenase. The presence of proteins capable of binding to EGF suggests the possibility of EGF-like regulation in plants.

Amino Acid Sequence↗
PubMed1996

Effect of maternal adrenalectomy and corticosterone therapy on the early development of B-cells in the fetal pancreatic islet in the rat.

Pregnant Wistar rats were divided into 3 groups, non-operated control, adrenalectomized, and adrenalectomized and corticosterone-treated. Maternal adrenalectomy was performed on day 6 of gestation. Corticosterone therapy was made from the day at operation to the day at observation. The growth pattern of insulin-producing B-cells was observed immunohistochemically and histometrically from days 12 to 16. The results obtained were as follows: From day 12 to day 15, maternal adrenalectomy resulted in a significant retardation of the growth of insulin-positive B-cells in terms of the collective volume of the cells. Maternal corticosterone therapy prevented this retardation. On day 16, however, the growth of B-cells in collective volume overcame the suppressive effect of maternal adrenalectomy. These results suggest that the lack of adrenocortical hormones causes a retardation of B-cell growth in early development, and that, when once developed well, B-cells can grow independently of the hormones.

Adrenalectomy↗
PubMed1996

Fine structures of perikaryal myelin sheaths on statoacoustic ganglion cells in 3-day-old chicks.

Perikaryal myelin sheaths on statoacoustic ganglion cells in 3-day-old chicks were studied by electron microscopy. The fixation method with a high-concentrated warm fixative helped in successful demonstrations of perikaryal myelin structures. The sheaths were composed of loose and compact myelin mixed by various arrangements. Twenty-seven percent of perikarya were entirely encircled by compact myelin, 71% were partly wrapped by compact myelin, and 2% were wrapped by just loose myelin. The perikaryal myelin was composed of 3 to 16 layers of loose and compact lamellae, whereas the axonal myelin of 10 to 28 of compact lamellae. Since no unmyelinated perikarya, which are covered by a single layer of Schwann cell cytoplasm, were detected, it is suggested that the perikarya myelination on all the ganglion cells has started before 3 days after hatching.

Animals↗
PubMed1996

[Depression of cellular immunity after aortic arch replacement].

Multiple organ failure due to infection is now one of the most serious postoperative complications following aortic arch replacement. We therefore evaluated the postoperative changes of cellular immunity using four parameters, 1) peripheral lymphocyte subsets 2) mitogen responsiveness 3) the activity of natural killer (NK) cells 4) interleukin-2 (IL-2) production. Patients were divided into two groups: group A (n = 5) with aortic arch replacement and group B (n = 10) with coronary artery bypass grafting. All variables were measured the day before, the day after, 3 days after, 7 days after, and 14 days after surgery. CD3 positive cells in group A were significantly lower than in group B throughout the postoperative course. CD4 positive cells in group A were significantly lower than in group B on the day after 3 days after the operation. IL-2 production in group A was markedly depressed the day after (all patients 0.8 U) and 3 days after (1.5 +/- 1.6 U) as compared to the preoperative level (7.7 +/- 4.4 U) and the levels on the same days in group B. The activity of NK cells in group A was significantly impaired the day after (10.6 +/- 6.7%) and 3 days after (10.0 +/- 6.7%) as compared to the preoperative level (28.6 +/- 16.7%) and the levels on the same days in group B. IL-2 production in group A was significantly correlated to CD3 and CD4 positive lymphocyte levels. These results clearly showed that patients who underwent aortic arch surgery suffered functional depression of cellular immunity, in particular IL-2 production and the activity of NK cells. These depressions may be a result of massive blood transfusion, tissue trauma under hypothermic cardiopulmonary bypass.

Aged↗
PubMed1996

[Maze operation for chronic atrial fibrillation with valvular heart diseases].

Between July 1994 and August 1995, 14 patients underwent combined modified maze procedure and valvular surgery including 5 patients having reoperation. Associated procedures were performed with mitral valve operation (n = 13), tricuspid annuloplasty or valve replacement (n = 9) and aortic valve replacement (n = 4). Duration of atrial fibrillation (AF) varied from 1 to 18 years (mean 8.0 +/- 5.8 year), the f-wave voltage ranged from 0.05 to 0.5 mV (0.21 +/- 0.13 mV), left atrial dimension (LAD) ranged from 35.6 to 66.3 mm (49.0 +/- 9.3). One patient died 2 months after undergoing combined maze procedure and MVR + TAP due to pulmonary infection and sepsis, but the other 13 patients survived. Nine patients (69%) regained atrial rhythm, two patients (15%) had junctional rhythm and another two (15%) remained in AF at follow-up periods between 1 to 11.5 months (6.3 +/- 3.1). The nine patients who recovered to normal sinus rhythm had preoperative f-wave for a significant higher voltage than the patients with AF and JR (0.27 +/- 0.12 vs 0.13 +/- 0.05 mV, p < 0.05) and a smaller left atrial dimension (44.5 +/- 0.7 vs 54.8 +/- 6.9 mm, p < 0.05). These data suggest that the maze operation is effective and should be considered for patients with chronic AF indicated for surgical valvular diseases.

Adult↗
PubMed1996

[Pseudoxanthoma elasticum with pulmonary calcification].

A woman born in 1920 had had multifocal, yellowish nodules on her skin since childhood and had been given a diagnosis of pseudoxanthoma elasticum. When she was 59-year-old, a diffuse granular shadow was seen on a chest radiograph. When she was 74-year-old, she presented with dyspnea on exertion. A thoracoscopic lung biopsy was done. Histologic examination of the lung tissue revealed small calcified nodules scattered in the alveolar septa. Pseudoxanthoma elasticum is a systemic, hereditary disorder that usually affects elastic fibers of the skin, eye, and cardiovascular system. It's incidence is quite low: 1 out of 160,000-1,000,000 population. Very few cases of pseudoxanthoma elasticum with pulmonary involvement have been reported, and we know of no previous case in Japan in which pulmonary microcalcification was confirmed histologically.

Aged↗
PubMed1996

[Surgical results of two cases of simultaneous carotid endarterectomy and coronary artery bypass grafting].

Reports on simultaneous revascularization operations for concomitant stenoses of the carotid and coronary arteries are many in Europe and America but few in Japan. Herein we report two cases of successful combined carotid endarterectomy and coronary artery bypass grafting. The first case was a 56-year-old male who had effort angina and a right carotid bruit with tinnitus. He was revealed to have severe stenosis of the right internal carotid artery as well as significant lesions of the right coronary artery. The second case was a 69-year-old male who had unstable angina and a left carotid bruit with a history of transient ischemic attack. Coronary angiography revealed three vessel disease and carotid digital subtraction angiography also revealed critical stenosis of the left internal carotid artery. In both cases, simultaneous carotid endarterectomy with an internal shunt and coronary artery bypass grafting were performed with a successful outcome. The use of internal shunt on reconstruction of the carotid artery was effective for protecting the brain.

Angina Pectoris↗
PubMed1996

[Late arrhythmias after the Fontan operation].

To study the incidence of late postoperative arrhythmias and to assess the possible risk factors related to such arrhythmias after the Fontan operation, we retrospectively reviewed standard 12-lead electrocardiogram (ECG) and Holter monitoring (Holter) of 21 patients who survived the Fontan operation between September 1982 and December 1992. Late postoperative supraventricular arrhythmias were detected in 7 of 21 patients by ECG, and in 10 of 17 patients by Holter. Older patients undergoing the Fontan operation had greater incidence of late postoperative supraventricular arrhythmias than younger patients. Patients undergoing superior vena cava-pulmonary artery anastomosis to prevent the right atrial distension had less incidence of late supraventricular arrhythmias detected by Holter. Thus, supraventricular arrhythmias are common in patients after the Fontan operation and may cause morbidity and mortality. Therefore, it is important to prevent the development of late arrhythmias by procedures designed to reduce atrial pressure at younger age.

Adolescent↗
PubMed1996

[A case report of coronary artery bypass grafting in a patient with Sjögren's syndrome].

There have been very few reports on coronary artery bypass grafting (CABG) during collagen disease. This paper reports a 49-year-old female suffering angina after myocardial infarction who revealed preoperatively findings such as arthralgia, thrombocytopenia and positive anti-nuclear antibody. She underwent CABG and was definitely diagnosed as Sjögren's syndrome after the surgery. The coronary artery lesion in this case was mainly attributed to coronary arteritis due to Sjögren's syndrome because she was comparatively young and no other coronary artery risk factors such as hypertension, hyperlipidemia, thickened intima or angitis had been found by aortic pathology. Moreover, anticardiolipin antibody, which is highly related to the myocardial infarction in juveniles, was positive in this case.

Angina Pectoris↗
PubMed1996

[Investigation on 19 operated cases of intrathoracic thyroid tumors].

We investigated in this paper nineteen patients who had undergone removal of intrathoracic thyroid tumors. They were 4 males and 15 females, aged 22-73 years, on the pathological classification, 4 with follicular adenomas, 4 with adenomatous goiters, 6 with papillary carcinomas, 1 with follicular carcinoma, 3 with papillary and follicular mixed carcinomas and 1 with anaplastic carcinoma. A 10-year survival rate of carcinomas is 77.1%, and there were 4 cases that had long term interval (6-30 years) between removal of cervical thyroid carcinoma and finding out of intrathoracic thyroid carcinoma. One case of follicular adenomas gave rise to metastasis to lung after four years from removal of intrathoracic tumor, and so it is necessary to do a long term observation after removal of thyroid tumors.

Adenocarcinoma, Follicular↗
PubMed1996

[Experimental study of safe limits of retrograde cerebral perfusion].

Safe limits of retrograde cerebral perfusion (RCP) which is now used as an adjunctive method in the surgical treatment of the aortic arch aneurysm were examined experimentally using adult mongrel dogs. After the brain was cooled to 20 degrees C by extracorporeal circulation, RCP was performed from the bilateral maxillary veins, and later, the brain was warmed up to the initial temperature. Experimental groups were divided into two groups; Group I (n = 5) were subjected to cerebral perfusion for 60 minutes, and Group II (n = 8) for 90 minutes. Cerebral function was evaluated using somatosensory evoked potentials (SEP). Cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) were measured, and histopathological examination was conducted SEP disappeared immediately after the initiation of RCP. In Group I, all the wave forms were recovered by rewarming in every animals, but the amplitude was only 35.0 +/- 16.6% of the preoperational value. In Group II, wave forms were not recovered in 3 animals of 8. CBF during RCP was minimal and about 2% of CBF observed before operation in either group. CMRO2 after being rewarmed up in Group II was lower than that in Group I, but this difference was statistically insignificant. In the histopathological examination, no ischemic change was found in Group I, while many cells indicating ischemic change were found in Group II. These findings indicate that RCP at 20 degrees C could not supply sufficient blood to brain tissues, and the brain can be injured irreversibly when the RCP exceeds more than 60 minutes.

Animals↗
PubMed1995

Thrombosed tricuspid valves presenting some 20 years after the surgical correction of Ebstein's anomaly: report of two cases.

We present herein the cases of two patients who were diagnosed as having thrombosed tricuspid valves by electrocardiography after undergoing valve replacement with Starr-Edwards caged ball valves for Ebstein's anomaly 19 and 27 years earlier. In both patients, the valves were found to be attached to the right ventricular septum and covered with massive thrombus, the balls being completely jammed in a half-open position in the cages. Re-replacement of the valves was successfully performed with Hancock II porcine heterograft prostheses and both patients are now classified as being in Functional Class I or II.

Adolescent↗
PubMed1995

Mid-term surgical results after valve replacement with the CarboMedics valve prosthesis.

We present herein a review of 95 patients who underwent valve replacement with the CarboMedics (CM) valve prosthesis between April 1990 and December 1992. The operative mortality for the entire group was 4.2%: 0% following aortic valve replacement (AVR), 2.7% following double valve replacement (DVR). All patients were prescribed warfarin and bucolome for anticoagulation, and were followed up for a mean period of 29.9 months. Late mortality was 8.4%; 3.1% following AVR, 10.8% following MVR, and 12.5% following DVR. There were no cases of mechanical prosthetic valve failure, significant hemolysis, infective prosthetic valve endocarditis, or bleeding complications. After 44 months of follow-up, the actuarial freedom from complications was calculated as: thromboembolism, 97.8 +/- 1.6%; valve thrombosis, 97.8 +/- 1.1%; paravalvular leak, 96.7 +/- 1.9%; and reoperation, 98.9 +/- 1.1%. The overall survival rate was 84.3 +/- 6.3% and all survivors showed a significant improvement in NYHA functional class, from 81% in classes III and IV preoperatively to 99% in classes I and II postoperatively. The CM valve exhibited no significant differences in hemolytic parameters or hemodynamic performance after isolated AVR or MVR compared with the similar type of St. Jude Medical bileaflet valve. The evidence provided by the present study therefore suggests that the CM valve prosthesis can achieve excellent mid-term clinical results and hemodynamic performance with a low incidence of thromboembolism and valve thrombosis.

Adolescent↗
PubMed1995

Experimental study on the optimum flow rate and pressure for selective cerebral perfusion.

The optimum flow rate and pressure for selective cerebral perfusion during moderate hypothermia (25 degrees C) were investigated in 36 mongrel dogs. Cerebral perfusion was performed for 90 minutes at a flow rate of 100% (the physiologic flow rate), 50%, 25%, and 0%, or no flow (cerebrocirculatory arrest). Somatosensory evoked potentials were monitored to assess brain function. An excess lactate level was considered an index of anaerobic cerebral metabolism, and histopathologic evaluation was performed. Somatosensory evoked potentials showed no abnormalities at flow rates of 100% and 50%, but became abnormal in some dogs at 25% and in all dogs under no-flow conditions. The excess lactate level only increased at a no-flow rate, but not significantly. Histopathologic evaluation showed no ischemic changes at flow rates of 100% and 50%, but there were slight ischemic changes at 25% and severe ischemic damage at no flow. The mean carotid arterial pressure was 63.1 +/- 5.9, 39.8 +/- 6.2, 24.9 +/- 6.0, and 11.3 +/- 3.5 mm Hg at a flow rate of 100%, 50%, 25%, and no flow, respectively. These results suggest that the safe range of flow rates for cerebral perfusion during moderate hypothermia is more than 50% of the physiologic level with a carotid arterial pressure of about 30 mm Hg or more.

Animals↗
PubMed1995

[Aortic arch aneurysm: new modification of aortic arch reconstruction and selective cerebral perfusion].

Selective cerebral perfusion (SCP) has been widely used as the method for cerebral protection during aortic arch repair in the treatment of aortic arch aneurysms in our institution. Recently, we modified our technique of aortic arch reconstruction and SCP in order to reduce the neurological complication. Following institution of SCP into both innominate and left common carotid arteries at 22 degrees C, the distal graft anastomosis and left subclavian reconstruction were performed while the descending aorta was left opened. Then the antegrade perfusion with rewarming was started via the fourth limbs attached to the main graft instead of the femoral artery. The aortic arch was completely replaced with the graft with three limbs for arch vessels. During one-year period from December 1993 to November 1994, 30 patients were operated on for aortic arch aneurysms using this technique. The etiology of aneurysms was true aneurysms in 16 patients, and aortic dissection in 14 including 8 cases of acute dissection. The concomitant procedures included descending graft replacement in 11 patients, composite graft replacement in 5, CABG in 3, and AVR in 1. The hospital mortality was 3.3% (1 of the 30 patients). There was no neurological complication. We conclude that the present techniques are useful methods for preventing the neurological complication in the treatment of aortic arch aneurysms.

Adult↗