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Genjiro Kimura

Publications and source records attributed to Genjiro Kimura.

At least 19 recordsLinked to original sources
PubMed2006

Lack of inertia force of late systolic aortic flow is a cause of left ventricular isolated diastolic dysfunction in patients with coronary artery disease.

OBJECTIVES: We investigated whether a lack of inertia force of late systolic aortic flow and/or apical asynergy provoke early diastolic dysfunction in patients with coronary artery disease (CAD). BACKGROUND: Left ventricular (LV) isolated diastolic dysfunction is a well-recognized cause of heart failure. METHODS: We evaluated LV apical wall motion and obtained left ventricular ejection fraction (LVEF) by left ventriculography in 101 patients who underwent cardiac catheterization to assess CAD. We also computed the LV relaxation time constant (Tp) and the inertia force of late systolic aortic flow from the LV pressure (P)-first derivative of left ventricular pressure (dP/dt) relation. Using color Doppler echocardiography, we measured the propagation velocity of LV early diastolic filling flow (Vp). Patients with LVEF > or =50% (preserved systolic function [PSF], n = 83) were divided into 2 subgroups: patients with inertia force (n = 53) and without inertia force (n = 30). No patient with systolic dysfunction (SDF) (LVEF <50%) had inertia force (n = 18). RESULTS: The Tp was significantly longer in patients with SDF (85.7 +/- 21.0 ms) and with PSF without inertia force (81.1 +/- 23.6 ms) than in those with PSF with inertia force (66.3 +/- 12.8 ms) (p< 0.001). The Vp was significantly less in the former 2 groups than in the last group. In patients with PSF, LV apical wall motion abnormality was less frequently observed in those with inertia force than in those without (p < 0.0001). CONCLUSIONS: An absence of inertia force in patients with PSF is one of the causes of isolated diastolic dysfunction in patients with CAD. Normal LV apical wall motion is substantial enough to give inertia to late systolic aortic flow.

Aged↗
PubMed2006

Hypothesis on renal mechanism of non-dipper pattern of circadian blood pressure rhythm.

In some patients with sodium sensitive type of hypertension or kidney disease, blood pressure (BP) fails to dip during night and they have been called "non-dipper", whereas those with a normal nocturnal dip are called "dipper". Many investigators reported that non-dippers were certainly exposed to greater risks of cardiovascular complications. We have recently proposed that kidneys play an important role in determining the circadian rhythm of BP, in addition to long-term BP regulation. When sodium intake is high, the defect in sodium excretory capability of kidneys becomes evident, making BP during night elevated, that is non-dipper, in order to compensate for diminished natriuresis during daytime and to enhance pressure-natriuresis during night. Therefore, as renal function deteriorates, longer duration may be required before BP begins to dip during night. Non-dipping may be one mechanism causing cardiovascular events in chronic kidney disease.

Blood Pressure↗
PubMed2006

Polynocturia in chronic kidney disease is related to natriuresis rather than to water diuresis.

BACKGROUND: Nocturnal polyuria has been well known in renal insufficiency. Recently, we found that as renal function deteriorated in chronic kidney disease (CKD), natriuresis was enhanced during the night with nocturnal blood pressure elevation. In the present study, we investigated whether nocturnal polyuria in CKD was due to the inability to concentrate urine, as previously proposed, or based on osmotic diuresis mainly by natriuresis. METHODS: In 27 CKD patients, circadian rhythms of urinary sodium, potassium, urea and osmolar excretion rates (U(Na)V, U(K)V, U(urea)V, U(osm)V) as well as of urinary volume (V) and free-water clearance (C(H(2)O)) were estimated during both daytime (6:00 to 21:00) and nighttime (21:00 to 6:00). Then, the night/day ratios of these parameters were analysed in relation to creatinine clearance (C(cr)) as a marker of glomerular filtration rate. RESULTS: C(cr) had significantly negative relationships with night/day ratios of V (R = -0.69; P < 0.0001), U(osm)V (R = -0.54; P = 0.004) and U(Na)V (R = -0.63; P = 0.0005), but no correlation with night/day ratios of C(H(2)O) (R = -0.33; P = 0.1), U(K)V (R = -0.29; P = 0.1) or U(urea)V (R = -0.31; P = 0.1). Linear and multiple regression analysis identified nocturnal natriuresis rather than urea excretion as an independent determinant of nocturia. CONCLUSION: As renal function deteriorated, nocturnal polyuria was seen, being consistent with classical recognition. Furthermore, this increase in nocturnal urine volume seemed related to osmotic diuresis mainly by natriuresis rather than to water diuresis or urea excretion.

Blood Pressure↗
PubMed2006

Proposal for mapping renal failure in Japan and its application for strategy to arrest endstage renal disease.

Remarkable regional differences in the annual incidence of endstage renal disease (ESRD) was found within Japan, which has a relatively homogeneous ethnic composition. In addition, there existed no regional difference in the incidence of ESRD due to polycystic kidney disease, the major genetic disorder of the kidneys. These findings suggest that the presence of factors other than genetic disposition contribute to the differences. On the other hand, there were similar regional variations in the incidences of ESRD between two causes of ESRD: chronic glomerulonephritis and diabetic nephropathy. Because it is unlikely that the regional distribution of underlying disease incidence and the disease-specific progression rate would be similar for two different causes, this observation suggests that factors governing the progression rate, which operate commonly for all causes of ESRD but differ among regions, may play an important role in generating the regional differences. Finally, we examined regional differences in the amounts of inhibitors of the renin-angiotensin system used, especially angiotensin-converting enzyme (ACE) inhibitors, in our search for an explanation of the regional differences in ESRD dynamics. Among antihypertensive agents examined, only ACE inhibitors were negatively correlated with the annual incidence of ESRD. The renal protective effects of ACE inhibitors have been established by results with animal models of progressive nephropathy and by large-scale clinical trials. Our epidemiological results for Japan as a whole show the same protective effects still more convincingly from a different approach. It is not completely clear yet at present, however, how regional variations in the incidence of ESRD are generated. If we could identify in future the factors that contribute to the regional differences, strategies for the treatment of renal disease will become available from different angles. Thus, much effort will be encouraged for the further analysis of regional differences in ESRD dynamics.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2006

Enhanced sodium sensitivity and disturbed circadian rhythm of blood pressure in essential hypertension.

OBJECTIVE: To assess whether an association between sodium-sensitive hypertension and metabolic syndrome exists; and whether, in patients with metabolic syndrome, the nocturnal fall of blood pressure decreases and salt restriction affects the circadian blood pressure rhythm. METHODS: Japanese patients with essential hypertension, who were treated without any antihypertensive agent, were maintained on a high-sodium diet and a low-sodium diet for 1 week each. On the last day of each diet, the 24-h blood pressures were measured. A diagnosis of metabolic syndrome was made according to the International Diabetes Foundation definition RESULTS: Among the 56 patients with essential hypertension, 15 patients were complicated with metabolic syndrome while 41 patients were not. The nocturnal blood pressure fall was significant in patients without metabolic syndrome, while it was not so in patients with metabolic syndrome. Only in patients with metabolic syndrome was the nocturnal blood pressure fall enhanced by sodium restriction. The prevalence of sodium-sensitive hypertension in patients with metabolic syndrome was significantly higher than in those without metabolic syndrome (70.6 versus 36.0%, respectively; P = 0.017). A multiple logistic regression analysis revealed central obesity to be an independent risk factor for sodium-sensitive hypertension (odds ratio, 1.41; 95% confidence interval, 1.04-1.91). CONCLUSIONS: In patients with essential hypertension, an inter-relationship exists among metabolic syndrome, enhanced sodium sensitivity of the blood pressure and non-dipping. The elevated risk of cardiovascular diseases in patients with metabolic syndrome may be related to sodium-sensitive hypertension and non-dipping.

Adult↗
PubMed2005

Usefulness of plasma brain-type natriuretic peptide level to differentiate left ventricular diastolic dysfunction from preserved diastolic function in patients with systolic dysfunction.

The extent of left ventricular (LV) diastolic dysfunction is related to the finding that some patients with cardiomegaly due to LV systolic dysfunction have good exercise tolerance, although others have limited tolerance. A brain-type natriuretic peptide level of >/=104 pg/ml reliably enables the detection of relatively worse LV diastolic function in patients with systolic dysfunction, and this value may provide clinically useful information for the management of patients with cardiomegaly.

Biomarkers↗
PubMed2005

Impaired gastric motility and its relationship to gastrointestinal symptoms in patients with chronic renal failure.

BACKGROUND: Gastrointestinal (GI) symptoms are common in patients with chronic renal failure (CRF), but the pathogenesis of these symptoms is unclear. Gastric motor function in CRF patients remains controversial, and the correlation between GI symptoms and gastric motility is also unclear. The aim of this study was to elucidate the relationship between gastric motility and GI symptoms in patients with CRF. METHODS: Gastric motility was evaluated with cutaneously recorded electrogastrographs (EGGs) and gastric emptying of a solid meal, using 13C-octanoic acid breath testing, in 21 patients with predialysis endstage CRF and in 21 matched healthy controls. GI symptom severity was quantified in all patients. RESULTS: The CRF patients had a significantly lower incidence of normogastria postprandially and a lower power ratio than did healthy controls on the EGGs, with the CRF patients showing delayed gastric emptying. Three patients with normal gastric motility had no GI symptoms, and ten patients with both abnormal EGG and delayed gastric emptying had significantly higher GI symptom scores than the patients without abnormalities. CONCLUSIONS: The patients with CRF showed gastric hypomotility, including impaired gastric myoelectrical activity and delayed gastric emptying. Gastric hypomotility appears to be an important factor in the generation of GI symptoms in patients with CRF.

Adult↗
PubMed2005

Glomerular function reserve and sodium sensitivity.

In clinical nephrology, the glomerular filtration rate (GFR) has been recognized as the golden standard to assess renal function. However, a normal GFR does not necessarily mean normal filtration capability of the kidneys, because impaired filtration capability can be compensated for by elevating glomerular hydraulic pressure. Therefore, an early phase of glomerular dysfunction cannot be detected by the baseline GFR alone. On the other hand, glomerular capillary hypertension is widely recognized as one of the strong risk factors for the progression of nephropathies. Now, it is very important to imagine glomerular hemodynamics in each patient with nephropathy for detecting early dysfunction, as well as for evaluating risk factors. Here, I would like to summarize the current status of how an early phase of renal dysfunction can be detected in clinical practice. I truly anticipate that new methods to assess glomerular hemodynamics in humans will be developed in the near future.

Animals↗
PubMed2005

Thiazide diuretics enhance nocturnal blood pressure fall and reduce proteinuria in immunoglobulin A nephropathy treated with angiotensin II modulators.

OBJECTIVE: We examined whether thiazide diuretics could restore nocturnal blood pressure (BP) decline and reduce urinary protein excretion in patients with glomerulopathy treated with angiotensin II modulators (angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers). METHODS: Twenty-five Japanese outpatients (11 men, 14 women; mean age 43 +/- 12 years) with biopsy-proven immunoglobulin (Ig)A nephropathy, preserved renal function (serum creatinine concentration </=1.2 mg/dl), stable non-nephrotic proteinuria (0.5-3 g daily), and treatment with angiotensin II modulators were studied. The patients received a diuretic, trichlormethiazide (2 mg daily) for 4 weeks after a baseline period lasting for 4 weeks. RESULTS: Diuretic therapy significantly reduced conventional, 24-h, daytime and night-time blood pressures. Nocturnal blood pressure fall was significantly enhanced by diuretic therapy and a significant interaction existed between diuretic therapy and nocturnal fall in mean arterial pressure, which indicated that the degree of nocturnal blood pressure fall was affected by diuretic therapy. The urinary protein excretion rate was significantly reduced from 1.10 +/- 0.62 to 0.63 +/- 0.39 g/day by diuretic therapy. Diuretic/baseline ratio of urinary protein excretion rate was not correlated with diuretic/baseline ratio of conventional, 24-h and daytime mean arterial pressures, but with diuretic/baseline ratio of night-time mean arterial pressure (r = 0.54, P = 0.006). CONCLUSIONS: Diuretics enhanced nocturnal BP decline and reduced urinary protein excretion in patients with IgA nephropathy treated with angiotensin II modulators. The combination of angiotensin II modulators and diuretics may have additional therapeutic advantages in relieving the renal and cardiovascular risks by reducing nocturnal high blood pressure.

Adult↗
PubMed2005

QTc dispersion in haemodialysis patients with cardiac complications.

BACKGROUND AND AIMS: QTc dispersion (Maximum - Minimum QTc interval on a standard 12-lead electrocardiogram (ECG)) is a useful predictor of tachyarrhythmic events and related sudden cardiac death. Recent studies have reported that QTc dispersion is prolonged in patients receiving haemodialysis (HD), and it is often further prolonged following HD treatment. In the present study, we examine whether the patients who are susceptible to prolongation of QTc dispersion by HD are prone to life-threatening cardiovascular events and related deaths. METHODS: Forty-eight patients with cardiac symptoms such as chest pain (n = 32), arrhythmia (n = 2) or heart failure (n = 14) and receiving chronic HD treatment (40 males and eight females) were subjected to the present study. Twenty-six of a total 48 patients were given a diagnosis of ischaemic heart disease (IHD) by coronary angiography. Ten patients had cerebrovascular accidents and 11 patients had peripheral vascular disease. After the ECG recording, a prospective follow up was conducted for 37 +/- 24 months. RESULTS: During the follow-up period, 30 patients had cardiac events, and 23 including 18 cardiovascular deaths occurred as outcomes. Throughout the total period, patients who showed prolongation of QTc dispersion after HD had cardiovascular deaths with higher incidence than those did not show the prolongation. CONCLUSIONS: We consider that prolongation of QTc dispersion after HD treatment can predict the prognosis of patients with renal failure bearing cardiac complications. Great care is necessary for such patients if they show longer QTc dispersion and/or susceptibility for further prolongation after HD treatment.

Adult↗
PubMed2005

Different regional dynamics of end-stage renal disease in Japan by different causes.

BACKGROUND: We recently showed that there were clear regional differences in the dynamics of end-stage renal disease (ESRD) within Japan, which has an ethnically homogenous population. We speculate on the reason for these regional differences by correlating the regional distributions in the incidence of ESRD due to each of the following individual causes of ESRD: chronic glomerulonephritis (CGN), diabetic nephropathy (DMN) and polycystic kidney disease (PKD). METHODS: The number of ESRD patients entering maintenance dialysis therapy due to individual causes of renal disease in each prefecture was reported annually for a 6-year period by the Japanese Society for Dialysis Therapy. After combining data from several prefectures into 11 geopolitical regions in Japan, the mean annual incidence of ESRD across the 11 regions was correlated among the three causes of ESRD. RESULTS: There were significant regional differences in the incidence of ESRD due to CGN (P<0.0001) and DMN (P=0.0015), the distributions of which were similar to each other across the 11 regions. In contrast, no regional differences were found in the incidence of ESRD due to PKD (P=0.6) as the major genetic disorder of the kidneys, suggesting that genetic backgrounds are relatively uniform throughout Japan. The regional distributions due to PKD were not correlated with those due to other causes: CGN and DMN. CONCLUSION: Risk factors common to nephropathy progression, rather than an underlying disease incidence and genetic predisposition, might contribute to regional differences in the overall ESRD incidence in Japan. Other possibilities such as the prevalence of underlying diseases, and acceptance or rejection rates into treatment programmes must be considered further for better explanations.

Chronic Disease↗
PubMed2005

Evaluation of fatty acid beta-oxidation in patients with prior myocardial infarction in relation to myocardial blood flow, total oxidative metabolism, and left ventricular wall motion.

BACKGROUND: Fatty acid metabolism in patients with myocardial infarction (MI) who undergo coronary reperfusion has not been fully elucidated and was investigated in the present study using positron emission tomography. METHODS AND RESULTS: The clearance rate constant of 11C-acetate (acetate-Kmono) and that of 11C-palmitate (palmitate-Kmono) from the myocardium were calculated using a monoexponential equation in 14 patients with MI. A total of 155 regions of interest were classified based on coefficient of determination (R2) values of monoexponential curves for 11C-palmitate clearance: well fitted regions (R2>or=0.5) and poorly fitted regions (R2<0.5). Regional relative myocardial blood flow calculated from the initial distribution of 11C-acetate and left ventricular (LV) wall motion were also evaluated. Peak 11C-palmitate uptake (14,434+/-3,052 vs 12,016+/-3,088 counts/s, p<0.001) and percent clearance during acquisition (38.2+/-10.1 vs 23.6+/-11.4%, p<0.001) were significantly greater in the well fitted regions (n=111) than in the poorly fitted regions (n=44). Acetate-Kmono was significantly higher in the former than in the latter (0.0641+/-0.0099 vs 0.0476+/-0.0103 min-1, p<0.001). LV wall motion and regional relative blood flow were also significantly greater in the former regions. Palmitate-Kmono in the well fitted regions was significantly higher in normal LV wall motion areas than in hypokinesis areas (0.0363+/-0.0062 vs 0.0274+/-0.0057 min-1, p<0.001) CONCLUSIONS: Maintenance of myocardial fatty acid beta-oxidation with better myocardial blood flow is substantial in the preservation of total myocardial oxidative metabolism and LV wall motion in patients with MI. The finding that the early-phase clearance of 11C-palmitate is fitted with a monoexponential curve may provide important information in the evaluation of myocardial fatty acid beta-oxidation.

Aged↗
PubMed2005

Circadian blood pressure rhythm is disturbed by nephrectomy.

We recently illustrated a close relationship between glomerular filtration rate and circadian rhythm of blood pressure (BP) in patients with chronic kidney disease. However, it remains undetermined from such cross-sectional findings which occurs first, the loss of kidney function or the lack of nocturnal BP fall. In the present study, we examined whether circadian rhythm of BP is affected by unilateral nephrectomy for kidney donation to clarify this important issue. Fifteen healthy subjects (4 men, 11 women; aged 33 to 65 years; mean age 55 +/- 2 years) who underwent unilateral nephrectomy for kidney donation were studied. Ambulatory BP was monitored for 24 h, while serum and urinary samples were collected to estimate creatinine clearance before and on the 8th day after nephrectomy. Then, changes in the night/day ratios of mean arterial BP were analyzed in relation to the decrease in 24-h creatinine clearance as a marker of glomerular filtration rate by nephrectomy. Creatinine clearance was reduced by 29% in average from 84 +/- 6 to 60 +/- 4 ml/min by nephrectomy, while 24-h mean arterial BP values were 91 +/- 3 and 94 +/- 4 mmHg (p=0.08) before and after nephrectomy. Although mean BP (daytime, nighttime or night/day ratio) was not altered significantly by nephrectomy, the decrease in creatinine clearance was positively correlated with the increase in the night/ day ratio of mean BP (r=0.61, p=0.017). The decrease in creatinine clearance was not correlated with changes in either 24-h, daytime or nighttime mean BP. Our results suggest that unilateral nephrectomy disturbs the circadian rhythm of BP as a function of renal dysfunction without affecting absolute levels of BP. Non-dipping of BP seems the consequence of the loss of renal function, rather than the cause.

Adult↗
PubMed2005

Both HDL3 and HDL2 exert a powerful anti-oxidative and protective effect against acceleration of oxidative modification of LDL by ascorbic acid.

The objective of the present study was to establish whether high-density lipoprotein 3 (HDL3) or high-density lipoprotein 2 (HDL2) might show an anti-oxidative effect on the acceleration of the oxidative modification of low-density lipoprotein (LDL) by ascorbic acid from measurement of the agarose gel electrophoretic mobility of LDL. LDL was incubated without adding transitional-metal ions for 48 or 96 h in phosphate-buffered saline (PBS) alone, with ascorbic acid (20 microg/mL), or with both ascorbic acid (20 microg/mL) and HDL3 (200 microg protein/mL). The LDL autoxidation occurred in PBS alone. Although ascorbic acid significantly suppressed oxidative modification of LDL after incubation for 48 h, the opposite was true after 96 h. However, since the anti-oxidative ability of HDL2 shows a weaker tendency than that of HDL3, both HDL3 and HDL2 significantly inhibited this acceleration of oxidative modification of LDL by ascorbic acid as assessed by electrophoretic mobility. If there is an augmented oxidative modification of LDL due to ascorbic acid in vivo, HDL3 or HDL2 may thus have an important role in inhibiting this ascorbic acid-accelerated oxidation of LDL.

Antioxidants↗
PubMed2005

Solitary fibrous tumor of the uterus producing high-molecular-weight insulin-like growth factor II and associated with hypoglycemia.

We report a case of solitary fibrous tumor of the uterus producing high-molecular-weight insulin-like growth factor II (big IGF-II). A 78-year-old woman presented with a massive uterine tumor and worsening hypoglycemia. Endocrine and metabolic investigations revealed that her serum contained big IGF-II. Pathologic examination of the myometrial tumor showed spindle cells separated by thick collagen fibers. The tumor cells were immunoreactive for CD34 and IGF-II (inclusive of big IGF-II) but not smooth muscle actin or desmin. Postoperatively the hypoglycemia and the serum big IGF-II disappeared with recovery of suppressed insulin and growth hormone levels. Western blotting of the tumor extract revealed the presence of big IGF-II, the molecular weight of which was similar to that of aberrant serum IGF-II. To our knowledge, this is the first case of uterine solitary fibrous tumor.

Aged↗
PubMed2005

[Pathogenesis of edema and its classification].

Pathogenesis of edema is in depth considered based on Starling's rule on capillary fluid dynamics. Edema can be divided into 4 types based on the mechanisms causing edema: increased capillary hydrostatic pressure, decreased plasma oncotic pressure, enhanced hydraulic permeability of capillary walls, and lymphatic obstruction. Each of the types can be further divided into generalized and local forms. Edema, defined as the expansion of interstitial fluid compartment, is initiated by imbalance of Starling forces across capillary walls between plasma and interstitium, but is maintained by enhanced sodium reabsorption from renal tubules.

Edema↗