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Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 163 records · Page 9Linked to original sources
PubMed1998

Sequential changes in cardiac structure and function in patients with Duchenne type muscular dystrophy: a two-dimensional echocardiographic study.

BACKGROUND: Most patients with progressive muscular dystrophy of the Duchenne type (DMD) die of respiratory failure at approximately 20 years of age. However, some patients with DMD die of heart failure in relatively short periods of time. We investigated the long-term progression of cardiac impairment in patients with DMD by two-dimensional echocardiography. METHODS: We monitored 74 patients for 4 years with two-dimensional echocardiography. Patients were classified into four groups according to the 8-grade Swinyard-Dever system. We also evaluated the echocardiographic features of 22 other patients with DMD with studies performed within 1 year before their deaths. RESULTS: During the 4-year follow-up the left ventricle expanded, and regional left ventricular wall motion abnormalities developed in the posterior wall and apex. Almost all patients had myocardial dysfunction that progressed in parallel with their Swinyard-Dever stage. However, in a few patients who died of congestive heart failure, left ventricular dilation and circumferential left ventricular wall motion were severely impaired. CONCLUSIONS: Myocardial impairment is accelerated in patients with DMD who died of heart failure. Two-dimensional echocardiography is a useful tool for the early diagnosis of left ventricular dysfunction and provides useful information for the treatment of patients with DMD.

Adult↗
PubMed1998

Angiographic follow-up of internal thoracic artery for free bypass grafting.

BACKGROUND: The use of free internal thoracic artery (ITA) grafts in patients with smaller body surface areas has been questioned because of technical difficulties and inadequate graft flow. METHODS: To evaluate postoperative changes in the diameter of free ITA grafts, we performed coronary angiography immediately after coronary artery bypass grafting and then again at a mean of 42 +/- 6 months later. In 20 consecutively treated patients, 21 free ITAs were used as bypass conduits. Two ITA grafts that were patent at the time of the first angiography had closed at the second angiography. Postoperative changes in ITA graft diameter were measured in the 19 patent ITA grafts. RESULTS: At the first angiography, the mean diameters of the proximal, middle, and distal ITA grafts were 2.28 +/- 0.45 mm, 2.34 +/- 0.39 mm, and 2.12 +/- 0.38 mm, respectively. At the second angiography, the mean diameters of the proximal, middle, and distal ITA grafts were 2.85 +/- 0.50 mm, 2.89 +/- 0.53 mm, and 2.72 +/- 0.53 mm, respectively. All segments of the ITA grafts had dilated significantly between the first and second angiographic evaluations (p < 0.01). The percentage change in graft diameter was greater when the initial ITA diameter was less than 2.3 mm (32.0% +/- 28.0%) than when it was 2.3 mm or more (18.8% +/- 11.3%) (p < 0.05). CONCLUSIONS: The postoperative increase in free ITA graft diameter depends on coronary blood flow requirements.

Adult↗
PubMed1998

Remnant-like particle cholesterol is a major risk factor for myocardial infarction in vasospastic angina with nearly normal coronary artery.

We investigated the association of remnant-like particle cholesterol (RLP-C), with vasospastic angina (VSA). We selected 66 subjects with nearly normal coronary artery as a control group, and 74 VSA with nearly normal coronary artery, of whom 19 had prior myocardial infarction (MI). Coronary risk factors, triglyceride, lipoproteins and apolipoproteins were evaluated using stepwise discriminant analysis, smoking was the only discriminator of the control group from VSA and RLP-C was the only discriminator of VSA with MI from VSA without MI. In comparison between VSA with and without MI, using stepwise logistic regression analysis, the only significant variable was RLP-C, and odds ratio of RLP-C for MI was 1.59. Thus, RLP-C is a major discriminator of VSA with MI and appears to be a major risk factor for MI in VSA.

Adult↗
PubMed1998

Intradural extension of mucocele complicating frontoethmoid sinus osteoma: case report.

BACKGROUND: Osteomas of the paranasal sinus are often asymptomatic and are sometimes complicated by mucoceles, but intradural extension of such a mucocele has rarely been reported. CASE DESCRIPTION: This 67-year-old man with complaint of headache was diagnosed as having an intradural extension of a mucocele complicating an osteoma of the frontoethmoid sinus. A right frontobasal craniotomy was performed and a mucocele in the frontal sinus extending into the frontal lobe through two dural defects and the osteoma was removed completely. The patient was successfully treated without recurrence. CONCLUSION: The importance of radical surgery for such lesions and the relationship between osteomas and mucoceles are discussed.

Aged↗
PubMed1998

Comparison of effects of enalapril and nitrendipine on cardiac sympathetic nervous system in essential hypertension.

OBJECTIVES: The purpose of this study was to assess the effects of enalapril and nitrendipine on the cardiac sympathetic nervous system. BACKGROUND: Angiotensin-converting enzyme inhibitors and long-acting calcium channel blockers have been widely used in the treatment of cardiovascular diseases, in some of which sympathetic overactivity plays a major role in the pathophysiology and prognosis. However, little information is available on the effects of these drugs on the cardiac sympathetic nervous system. METHODS: 123I-metaiodobenzylguanidine (MIBG) cardiac imaging was performed before and 3 months after drug administration in 46 patients with mild essential hypertension. Twenty-two patients were treated with 5 to 10 mg of enalapril once a day, and the other 24 with 5 to 10 mg of nitrendipine once a day. For comparison, 20 normotensive subjects were also studied. RESULTS: There were no significant differences between the basal characteristics in the 2 hypertensive groups. In both hypertensive groups, both systolic and diastolic blood pressures were significantly reduced to similar levels after the 3-month drug treatment. Before the drug treatment, the 2 hypertensive groups had a significantly higher washout rate and lower MIBG uptake than the normotensive subjects. The heart-to-mediastinum ratio significantly increased (p < 0.0001), with decreased (p < 0.002) washout rate after drug treatment in the enalapril group, but with no significant changes in the nitrendipine group. CONCLUSION: Enalapril could suppress cardiac sympathetic activity and nitrendipine had no effect on it. The knowledge of antihypertensive drugs on the cardiac sympathetic nervous system appears to be helpful in selecting appropriate treatment in cardiovascular diseases.

3-Iodobenzylguanidine↗
PubMed1998

Nine-year follow-up study of heart rate variability in patients with Duchenne-type progressive muscular dystrophy.

OBJECTIVES: The purpose of this study was to investigate the progression of autonomic dysfunction in patients with Duchenne-type progressive muscular dystrophy (DMD) over time by using heart rate variability. BACKGROUND: Although previous studies suggest the presence of autonomic dysfunction in patients with DMD, the precise cause is not known. On the other hand, it is well known that analysis of heart rate variability provides a useful, noninvasive means of quantifying autonomic activity. High frequency power is determined predominantly by the parasympathetic nervous system, whereas low frequency power is determined by both the parasympathetic and sympathetic nervous systems. METHODS AND RESULTS: Frequency and time domain analyses of heart rate variability during ambulatory electrocardiographic monitoring were performed in 17 patients with DMD over a 9-year period. At the time of entry, the mean patient age was 11 years and the mean Swinyard-Deaver stage was 4. In the first year, high frequency power was significantly lower and the ratio of low frequency to high frequency was significantly higher in patients with DMD than in the normal control subjects. These differences become significantly greater as the disease progressed. At the time of entry, low and high frequency powers increased at night in both groups. However, over time, high and low frequency powers at night tended to decrease. All of the time domain parameters were significantly lower in the patients with DMD at all time points compared with the normal control subjects. CONCLUSIONS: We concluded that DMD patients have either a decrease in parasympathetic activity, an increase in sympathetic activity, or both as their disease progresses.

Adolescent↗
PubMed1998

Diagnosis and treatment of malignant lymphoma of the parotid gland.

BACKGROUND: To correlate the imaging and pathological features and to discuss therapeutic modalities and the prognosis of malignant lymphoma originating in the parotid gland, which is relatively rare. METHODS: The subjects were five patients with malignant lymphoma originating in the parotid gland. Three and two patients were stage I and stage II, respectively. CT examination was applied to all, whereas only one case was examined by MRI. All were treated with radiotherapy following surgery or chemotherapy. Three patients underwent combination chemotherapy, such as with MACOP-P or VEPA, following surgery. RESULTS: Although malignant lymphoma originating in the parotid gland is histologically described as low-grade non-Hodgkin's lymphoma, two and one of the cases were classified as intermediate and high grade in the present series, respectively. These three exhibited a tendency for infiltration into the adjacent tissue and tumor inhomogeneity in the imaging findings, suggesting a correlation with histologically intermediate or high-grade non-Hodgkin's lymphoma. It was successfully controlled by radiotherapy, with dosages ranging from 40 to 44 Gy. The patients were followed for 2-8 years. No relapse was found in the three patients with stage I. However, both stage II patients had relapses and were subjected to additional radiotherapy combined with chemotherapy. Since then, no tumor relapse has been noted at either this or other sites. CONCLUSIONS: Malignant lymphoma including intermediate or high grade originating in the parotid gland indicated satisfactory prognosis following radiotherapy and chemotherapy.

Aged↗
PubMed1998

Mucoepidermoid carcinoma of the larynx: a case which responded completely to radiotherapy and a review of the literature.

Most laryngeal cancers are squamous cell carcinomas, and adenocarcinomas account for < 1% of cancers of the larynx. Among them, mucoepidermoid carcinoma is extremely rare and there is little agreement about the treatment of this carcinoma. We encountered one patient with mucoepidermoid carcinoma of the bilateral vocal cords (T1bN0M0, Stage 1). For this, most investigators recommended a surgical procedure. However, because of his old age, the early stage and low grade of histopathology, we treated this patient with radiotherapy alone, delivered by accelerated hyperfractionation, which is a more effective strategy for treating radioresistant tumors than conventional irradiation. Following radiotherapy, the tumor disappeared and the patient has been alive and well for more than six years. An old patient with mucoepidermoid carcinoma of the larynx was successfully treated with radiotherapy alone.

Aged↗
PubMed1998

Radiotherapy in the management of Graves' ophthalmopathy.

BACKGROUND: To report the results of radiotherapy for patients with failure, adverse reactions or relative contraindications to the use of steroids or immunosuppressants, by using newly developed quantitative indexes. METHODS: Fourteen female and six male patients with Graves' ophthalmopathy were treated with radiotherapy between 1989 and 1996. Prior to radiotherapy, eight patients received treatment with prednisone, four received immunosuppressants and four received a combination of both. Four patients with contraindications to steroids were initially managed with radiotherapy. Most of the patients received a dose of 24-28 Gy in 2 Gy fractions. We used the newly developed motility limitation index to assess extraocular motility. RESULTS: Treatment was well tolerated. There have been no late complications. All 12 patients with soft tissue signs such as edema, irritation, tearing and pain were improved. Proptosis did not improve or improved only slightly, 3 mm at best. However, proptosis in all but two has been stabilized and has not deteriorated in the follow-up period. Most of the patients have experienced an improvement of eye-muscle motility. Extraocular muscles that work for elevation were impaired more severely than the other muscles and this tended to remain. Of the 16 patients using steroids before or when radiotherapy was initiated, 15 were tapered off and only one patient required additional steroids, thus sparing the majority from steroid adverse reactions. CONCLUSION: Radiotherapy was effective in preventing exacerbations of active inflammatory ophthalmopathy in patients with Graves' disease with minimal morbidity and thus eliminated the adverse reactions associated with protracted corticosteroid use. The newly developed motility limitation index was useful in detecting delicate changes in motility of individual extraocular muscles.

Adult↗
PubMed1998

Relationship between spontaneous aminoglycoside resistance in Escherichia coli and a decrease in oligopeptide binding protein.

Changes in the amount of oligopeptide binding protein (OppA) in spontaneous kanamycin-resistant mutants of Escherichia coli were investigated. Among 20 colonies obtained from 10(8) cells cultured in the presence of 20 microgram of kanamycin/ml, 1 colony had no detectable OppA and 7 colonies were mutants with reduced amounts of OppA. Sensitivity of wild-type cells to kanamycin increased slightly by transformation of the oppA gene, but the sensitivity of the mutants increased greatly by the transformation. A mutant with no OppA was found to be a nonsense mutant of the oppA gene at amino acid position 166. In a mutant having a reduced level of OppA, the reduction was due to the decrease in OppA synthesis at the translational level. These mutants were also resistant to other aminoglycoside antibiotics, including streptomycin, neomycin, and isepamicin. Isepamicin uptake activities decreased greatly in these two kinds of mutants. The results support the proposition that aminoglycoside antibiotics are transported into cells by the oligopeptide transport system, and that transport is an important factor for spontaneous resistance to aminoglycoside antibiotics.

Amino Acids↗
PubMed1998

Comparison of filled-in myocardial segments after early and late reinjection of thallium-201--influence of the timing of reinjection on fill-in.

Thallium-201 (201Tl) late reinjection after stress-redistribution imaging improves the detection of viable myocardium. Recently, early reinjection of 201Tl immediately after stress imaging was proposed as a new method for distinguishing ischemic myocardium, hibernating myocardium, and myocardial scar. However, there are no data on the influence of the timing of reinjection on "fill-in." This study was designed to assess whether the reinjection time influences "fill-in" in chronic coronary artery disease. Thirty-three patients with chronic coronary artery disease were studied. All patients underwent exercise 201Tl tomography. Immediately after stress imaging, 37 MBq of thallium was reinjected earlier than usual and early reinjection delayed image (ERDI) was acquired 3 h later. With the same protocol, all patients also underwent a second study involving late reinjection of 201Tl within 1 week. An additional 37 MBq of thallium was reinjected 3 h after stress imaging, and late reinjection delayed image (LRDI) was obtained 10 min later. All images were analyzed qualitatively using a 4-point grading uptake score. Of the 72 hypoperfused segments on stress images, 66 segments showed fill-in and 6 showed persistent defects on ERDI, and of the same 72 segments 55 segments displayed fill-in and the remaining 17 showed persistent defects on LRDI (p<0.05). The delta uptake score (the uptake score of the delayed image minus that of stress image) in early reinjection was 1.60+/-0.80, which was significantly higher than that in late reinjection (1.24+/-0.94, p<0.01). A small dose of thallium reinjected immediately after stress imaging with delayed images obtained 3 h later is convenient and might provide another technique for determining myocardial viability.

Aged↗
PubMed1998

One additional mutation at exon A amplifies thermolability of androgen receptor in a case with complete androgen insensitivity syndrome.

We have previously demonstrated a substitutional mutation (glycine to alanine at position 820) of the androgen receptor (AR) gene in a patient with complete androgen insensitivity syndrome (CAIS). We first examined whether the mutation could lead to a disorder in AR binding activity in in vitro expression experiments. In a luciferase assay, the effect of the mutant AR on a target's gene was definitely impaired. However, the mutant AR had less thermal instability compared to that of the patient's fibroblast cell lines established in a whole-cell binding assay. In order to analyze the cause of the thermal instability, a further analysis of exon A in the AR gene was performed because the previous study had been performed only between exon B and H encoding the DNA-binding domain and the hormone-binding domain. The second mutation (leucine to proline at position 257) was newly identified. In in vitro expression experiments, the AR with both mutations showed marked thermal instability, whereas the AR with a mutation in exon A had no effect on thermal stability. The results show that the N-terminal domain might also play an important role in amplifying or modifying the AR binding activity.

Androgen-Insensitivity Syndrome↗
PubMed1998

Shortage of glutamine (CAG) homopolymeric repeats suppresses the expression of the androgen receptor in familial cases with complete androgen insensitivity syndrome.

The androgen receptor gene of two familial cases with complete androgen insensitivity syndrome was analyzed. The shortage of glutamine homopolymeric repeats (13 repeats) in the N-terminal domain of the androgen receptor of the patients was identified by DNA sequence analysis. In vitro transfection experiments with the patients' androgen receptor gene indicated that the expression of the androgen receptor in transfected COS-7 cells was decreased by 10% as compared to that of the wild type androgen receptor gene. The thermal stability of the 5 alpha-dihydrotestosterone-androgen receptor complex was also partially impaired. The capacity of the androgen receptor to activate target gene transcription was partially disturbed in a luciferase assay. The shortened glutamine homopolymeric repeats might therefore be related to the pathogenesis of complete androgen insensitivity syndrome.

Adult↗
PubMed1998

The effects of the hypothermic management of brain dead dogs on preserving graft viability in heart transplantation.

The effect of hypothermic management for brain dead dogs on preserving graft viability was evaluated through preservation and transplantation. After the occurrence of brain death, 43 dogs were divided into two groups; the normothermic group (37.2+/-0.3 degrees C) and the hypothermic group (31.8+/-0.3 degrees C) according to the esophageal temperature. After the 6-hour management of brain dead donors, the heart beat was arrested using a cardioplegic solution followed by coronary vascular bed washout. The donor heart was then harvested and preserved for 12 hours with simple immersion into the University of Wisconsin solution. Following preservation, orthotopic transplantation was performed in six grafts randomly selected from each group. During the 6-hour management of brain dead dogs; 1) heart rates, rate-pressure products, and the total amount of catecholamine were significantly (p<0.05) lower in the hypothermic group than in the normothermic group, and 2) lactate contents collected from the coronary sinus blood and O2-extraction rates of the heart tended to be lower in the hypothermic group than in the normothermic group. During 12 hours of preservation, intracellular pH and creatine phosphate contents were higher in the hypothermic group than in the normothermic group. Following orthotopic transplantation, the animals in the hypothermic group showed a significantly (p<0.05) higher recovery rate of left ventricular (LV) pressure and the maximum rate of the rise of LV pressure compared with normothermic group animals. We conclude that the hypothermic management of brain dead dogs may be effective in preserving graft viability and may provide a clinical application for heart transplantation with acceptable outcomes.

Adenosine↗
PubMed1998

Physiological fluctuation of the human left ventricle sympathetic nervous system assessed by iodine-123-MIBG.

UNLABELLED: It has been proposed that sympathetic nervous system pathophysiology is involved in the development of cardiovascular disorders. Since cardiac adrenergic activity has been difficult to assess in humans, physiological changes in the sympathetic nervous system in the human left ventricle remain unclear. METHODS: To determine if age and gender influence the sympathetic nervous function of the left ventricle, 300 angiographically normal subjects (170 men, 130 women; age range 40-79 yr) had 123I-metaiodobenzylguanidine (MIBG) cardiac imaging. Regional quantitative analysis of MIBG uptake and washout rate was performed. RESULTS: Men and women had prominent age-related decreases in MIBG uptake in the inferior and lateral walls (r2 = 0.34, p <0.0001 for both). Both genders had a significant positive correlation between regional washout rate and age in each region. In contrast to men, women had strong positive correlations in all regions (r2 = 0.54, p <0.0001 in the anterior wall, r2 = 0.56, p <0.0001 in the lateral wall and r2 = 0.44, p <0.0001 in the inferior wall). According to the decade-by-decade analysis of washout rate, women had a significantly lower washout than men under 50 yr in every region and a significantly higher washout in the lateral wall than men over 70 yr. CONCLUSION: The sympathetic nervous system in the human left ventricle showed age- and gender-related regional changes. The findings suggested that men have high sympathetic nerve activity from a younger age, and women have a progressive increase in sympathetic nerve activity with aging. These changes may contribute to the age and gender differences in the incidence and development of cardiac disorders.

3-Iodobenzylguanidine↗