Biomedical subjects
F Marumo
Publications and source records attributed to F Marumo.
[Filtration--hemofiltration and peritoneal diafiltration].
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Concentrations of brain natriuretic peptide in treated congestive heart failure.
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[Postoperative changes in immunoreactive plasma endothelin concentrations].
We investigated postoperative changes in immunoreactive plasma endothelin (ET-1) concentrations using a highly specific and sensitive radioimmunoassay developed for this purpose. The patients were divided into two groups: 10 patients underwent subtotal-esophagectomy by combined right thoracotomy and celiotomy (EC-group), and an other 10 underwent total gastrectomy via celiotomy only (GC-group). Before operation, plasma ET concentrations in both groups were within the normal range. After operation, the mean plasma ET-1 concentration in the EC group was significantly higher than the preoperative concentration (p less than 0.01). But in the GC-group, there were no significant change. A significant correlation existed between the change in plasma ET-1 concentration and the amount of intraoperative hemorrhage (p less than 0.05). Additionally in the EC group, a significant correlation existed between plasma ET-1 concentrations after operation and the change in the atrial-natriuretic-peptide (ANP) concentration during operation (p less than 0.05). There was no correlation between ET-1 concentrations and blood pressure. We believe that the increase in the ET-1 concentration was attributable to endothelial cell injury and may increase ANP secretion. We speculate that the plasma ET-1 concentration may be a reliable index of surgical stress.
Endothelin and renal failure.
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[Doppler hemodynamic evaluation of bioprosthetic valve failure in the mitral position].
M-mode and two-dimensional echocardiography (2DE) allows the accurate assessment of primary tissue degeneration of bioprosthetic valves. The Doppler method permits quantitative evaluation of the pressure gradient across the prosthetic valve or detection of regurgitant flow. The present study summarized our clinical experiences of serial cases of mitral valve replacement (MVR) with bioprostheses at the mitral position, and clarified the clinical usefulness and limitations of Doppler and 2DE examinations for the early detection of primary valve dysfunction. Consecutive 65 patients undergoing single mitral valve replacement from April, 1977 to November, 1979 were listed for the study. A survey of the present clinical status was carried out from July, 1988 to July, 1990 (a follow-up period ranged from 84 to 127 months) for all patients, and the information was available from 53 patients (47 adults and six infants). Twenty-four survived patients without re-MVR were examined by Doppler and 2DE. Among the 53 patients, 34 were alive and 19 dead, and the total survival rate was 64.2%. The reasons for death in 19 patients were perioperative death in seven (including four infants with severe calcification of bioprostheses), chronic heart failure in three, cerebral infarction in two, post blood transfusion hepatitis in two, endocarditis in one, and non-cardiac death such as cancers in four. During the long-term observation of 47 adult patients, 14 cases (30%) had re-MVR (one for a stenotic lesion with massive calcification, and 13 for torn leaflets). Thickening and/or torn leaflets were noted in 13 (54%) of the 24 survived patients without re-MVR.2+ suggests that bioprosthetic valve replacement at the mitral position may not be recommended.
[The prevalence and clinical features of pathologically abnormal mitral valve leaflets (myxomatous mitral valve) in the mitral valve prolapse syndrome: an echocardiographic and pathological comparative study].
We studied the prevalence and clinical features of pathologically abnormal mitral valve leaflets (myxomatous mitral valve: MMV) in consecutive 142 patients with the mitral valve prolapse syndrome (MVP). Our echocardiographic criteria for MMV were 1) thick leaflets 3 mm or greater, 2) redundant leaflet-motion, and 3) echo-density lower than that of the aortic walls. The echocardiographic measurements of left ventricular diastolic dimensions (LVDd), percent fractional shortening (%FS), mitral annular diameter (MAD), and LV mass were compared between MMV and non-MMV groups. Twelve patients (8%) were referred for surgery because of congestive heart failure, and two patients died during the observation periods. Gross morphology of the MMV was characterized by increased surface area, dome formation of the leaflet-body, and non-uniform leaflets in thickness, and histologic findings of the MMV were the infiltration of spongiosa layer into the fibrosa layer. The diagnostic accuracy of echocardiography for the MMV was examined in 14 patients underwent either surgery or autopsy, and it was high (78% in sensitivity and 80% in specificity). The progression of mitral regurgitation (MR) from mild to moderate grade or mild to severe grade was found in five of 26 patients during follow-up studies over 12 months (mean = 36 months). All of the five patients were aged 50 years and older. While, MR completely disappeared in a 17-year-old boy with marked physical development within three years of the observation period. Mitral annular diameter significantly increased in MMV with MR when compared to non-MMV with MR (4.1 +/- 0.7 vs 3.5 +/- 0.4). But no significant changes were noted in LVDd and LV mass between non-MMV with MR and MMV with MR. Of the 142 patients with MVP, 96 patients were non-MMV and 46 patients were MMV. Ruptured chordae tendineae were associated in 5/96 patients (5%) with non-MMV and 22/46 patients (48%) with MMV. Intracardiac vegetations were seen in four of the 96 patients (4%) with non-MMV. The prevalence of MMV in MVP was greater in older patients, and it reached nearly as high as 50% of MVP patients aged 60 years and older. In conclusion, the echocardiographic diagnostic criteria for MMV are reliable with high sensitivity and specificity, and are useful to predict the high risk patients in the MVP syndrome. MMV may be a potential etiology causing aggravation of mitral regurgitation and/or ruptured chordae tendineae.
Transcellular chloride transport in the proximal tubules: mechanisms and physiological significance.
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[Studies on plasma immunoreactive human brain natriuretic peptide (hBNP) levels in patients with congestive heart failure and present forms of hBNP in human cardiac ventricle].
By using a specific radioimmunoassay (RIA) for human brain natriuretic peptide (hBNP), we measured immunoreactive hBNP (ir-hBNP) in plasma from patients with congestive heart failure (CHF). There appeared to be relationship between the enhanced ir-hBNP secretory activity and the severity of the failing heart as well as that of immunoreactive human atrial natriuretic peptide (ir-hANP). However, the secretion of ir-hBNP was augmented much more than that of ir-hANP in sever CHF patients. Gel permeation chromatography coupled with the RIA revealed that ir-hBNP in human ventricle is composed with gamma-hBNP and hBNP (1-32) as well as that of human atrium. However, we found differences of the gamma-hBNP/hBNP (1-32) ratio in atrial and ventricular tissues. These findings suggest that the hBNP secretion mechanism differ in the two areas of human heart.
Intraoperative hemorrhage affects endothelin-1 concentrations.
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[Levels of endothelin-1 in maternal and cord plasma during pregnancy and delivery].
In order to elucidate the possible involvement of endothelin-1 (ET-1) in the development of the feto-placental unit, plasma concentrations of immunoreactive ET-1 during pregnancy and delivery were measured in the current study. Forty-four pregnant women (8 in the 1st trimester, 8 in the 2nd trimester, 12 in the 3rd trimester and 16 at delivery), 6 at 1 month postpartum and 14 non-pregnant women volunteered to participate in this study. Plasma levels of immunoreactive ET-1 in all subjects were measured by specific radioimmunoassay. Plasma cortisol, prolactin and oxytocin levels during delivery were also measured by RIA. Although plasma ET-1 levels did not change during the 1st (1.3 +/- 0.4 pg/ml, mean +/- S.E.M., n = 8) or 2nd (1.7 +/- 0.3 pg/ml, n = 8) trimester, they were significantly (p less than 0.05) higher in the 3rd trimester (2.6 +/- 0.3 pg/ml, n = 12) than those of the non-pregnant controls (1.7 +/- 0.3 pg/ml, n = 14) and returned to the control levels within 1 month post-partum (1.8 +/- 0.1 pg/ml, n = 6). Maternal ET-1 levels before labor onset (2.3 +/- 0.4 pg/ml, n = 16), at delivery (3.0 +/- 0.7 pg/ml) and 24 hours post-partum (2.7 +/- 0.5 pg/ml) showed no significant differences among them. On the other hand, ET-1 levels in cord plasma (7.0 +/- 1.2 pg/ml) were significantly higher (p less than 0.05) than those in maternal plasma. Furthermore, there were no significant correlations between plasma ET-1 levels and those of other hormones (cortisol, prolactin and oxytocin) during delivery. From these results, we concluded that maternal plasma ET-1 levels significantly increased in the last trimester and returned to non-pregnant levels within one month post-partum.
Production of endothelin-1 by rat cultured mesangial cells.
We investigated whether ET-1 is synthesized by and released from mesangial cells. ET-1-like immunoreactivity (LI) released into medium increased time-dependently under a serum-free condition. The amounts of ET-1-LI released into the medium was augmented in the presence of fetal calf serum. Reverse-phase HPLC profile of the conditioned media revealed a major component coeluting with standard ET-1. Northern blot analysis of poly(A) +RNA extracted from mesangial cells showed a single major band corresponding to the size of preproET-1 mRNA (2.3 kb). These findings demonstrate that ET-1 is synthesized by and released from rat mesangial cells and suggest a possibility that it acts on their own cells as an autocrine factor.
Cytokine-induced release of endothelin-1 from porcine renal epithelial cell line.
To elucidate the mechanism by which endothelin-1 (ET-1) is released from renal epithelial cells, we have investigated the effects of several compounds on release of ET-1-like immunoreactivity (LI) from LLCPK1 cell line. Thrombin, transforming growth factor-beta, cytokines (tumor necrotizing factor-alpha, interleukin-1 beta), and phorbol ester stimulated ET-1-LI release in a time- and dose-dependent manner. The cytokine-induced ET-1-LI release was not affected by indomethacin. Northern blot analysis using cDNA for porcine preproET-1 as a probe revealed a single major band corresponding to the size of ET-1 mRNA in LLCPK1. These data indicate that the preproET-1 gene is also expressed in renal epithelial cells and the release of ET-1 from renal cells is regulated by the similar mechanism to that from endothelial cells.
Plasma von Willebrand factor and thrombomodulin as markers of vascular disorders in patients undergoing regular hemodialysis therapy.
Increased plasma levels of von Willebrand factor antigen (vWF:Ag) are regarded as reflecting the release reaction by vascular endothelial cells and/or endothelial cell injury, and increased levels of thrombomodulin (TM) antigen as reflecting damage to endothelial cells. We investigated changes in plasma vWF:Ag and TM antigen levels during the course of regular hemodialysis treatment (RDT) in 14 patients undergoing RDT in order to evaluate the effect of hemodialysis (HD) on endothelial cells. vWF:Ag and TM were both measured by the sandwich EIA method. Predialysis levels of vWF:Ag and TM in RDT patients were both significantly higher than normal control values. Neither patient age nor blood pressure was not correlated with predialysis vWF:Ag and TM levels. Both vWF:Ag and TM levels significantly increased during a single HD session. There was a positive correlation between predialysis TM levels and duration of HD and an inverse correlation between the amount of vWF:Ag released during HD and duration of HD. It appears that HD procedures induce stimulation and damage of endothelial cells and that long-term, recurrent HD treatment may predispose to vascular disorders.
Specific receptors for endothelin-3 in cultured bovine endothelial cells and its cellular mechanism of action.
Among three endothelin (ET) isopeptides, ET-3 shows the most potent initial depressor response through the endothelium-dependent mechanism. We studied the presence of specific binding sites for ET-3 in cultured bovine endothelial cells (EC) and its cellular mechanism of action. Binding studies revealed the presence of two distinct subclasses of ET-3 receptors with high and low affinities. ET-3 dose-dependently (10(-10)-10(-7) M) increased both intracellular Ca2+ levels ([Ca2+]i) and inositol trisphosphate (IP3) formation. The ET-3-induced increase in [Ca2+]i was not affected by either removal of extracellular Ca2+ or Ca2(+)-channel blockers. These data suggest that ET-3 induces phosphoinositide breakdown and increase in [Ca2+]i in ECs, possibly resulting from intracellular Ca2+ mobilization, thereby leading to vasodilatation.
Presence of endothelin-1-like immunoreactivity in human cerebrospinal fluid.
By use of radioimmunoassay (RIA) specific for endothelin-1 (ET-1), we have studied whether ET-1-like immunoreactivity (LI) exists in human cerebrospinal fluid (CSF). Human CSF from patients with old cerebrovascular disease contained far greater amounts of ET-1-LI (28 +/- 1.3 pg/ml, n = 9) than normal human plasma. Reverse-phase HPLC coupled with ET-1 RIA revealed a single major ET-1-LI component in human CSF extract coeluting with standard ET-1. These data suggest ET-1 is a neuropeptide secreted from neural tissues in humans.
[Physiopathology and treatment of chronic kidney failure].
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