Biomedical subjects
N Yoshiyama
Publications and source records attributed to N Yoshiyama.
[Filtration--hemofiltration and peritoneal diafiltration].
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[Biofiltration, short-time dialysis].
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Unilateral renal agenesis associated with various metabolic disorders in three siblings.
Unilateral renal agenesis with impaired renal function was found in all 3 siblings of a single family, in association with various metabolic disorders such as diabetes mellitus, hyperuricemia and hyperbilirubinemia with gallstones. The present report suggests that unilateral renal agenesis could occur as a manifestation of a genetic disorder.
Effects of kinin on electrolytes transport and regulation of kininase activity in distal nephron segments of the rat.
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Effects of mineralocorticoid on kininase activity along the distal nephron segments of the rat.
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Leukotriene D4 inhibits atrial natriuretic factor-dependent cGMP production in rat glomerulus.
The effects of leukotriene D4 (LTD4) on guanosine 3',5'-cyclic monophosphate (cGMP) production induced by atrial natriuretic factor (ANF) or sodium nitroprusside (SNP) were investigated in isolated rat glomeruli. First, the isolated glomeruli were preincubated in Krebs-Ringer buffer containing 3-isobutyl-1-methylxanthine for 10 min, then incubated with varying concentrations of ANF, SNP, and LTD4 for 3 min. cGMP content was determined by radioimmunoassay. cGMP production (fmol.glomerulus-1.3 min-1) was not increased by LTD4. cGMP accumulation was increased by ANF (1 microM) and SNP (100 microM) remarkably from 0.19 +/- 0.09 to 3.24 +/- 0.21 (n = 7, mean +/- SE), and from 0.19 +/- 0.09 to 3.67 +/- 0.47 (n = 4), respectively. The increase in cGMP production by ANF was significantly and dose-dependently inhibited by LTD4 (P less than 0.05). Maximum suppression was observed at the concentration of 100 nM (from 3.06 +/- 0.33 to 1.43 +/- 0.09; P less than 0.05). However, LTD4 caused no significant change in the level of cGMP production induced by SNP. Second, particulate or soluble guanylate cyclase from glomeruli were similarly investigated. ANF selectively activated particulate guanylate cyclase and the response was selectively inhibited by LTD4 from 9.07 +/- 1.79 fmol.micrograms-1.3 min-1 (n = 6) to 4.70 +/- 0.70 (n = 6, P less than 0.05). These results suggest the site where LTD4 has effect on cGMP production induced by ANF was the particulate guanylate cyclase system, but not the soluble guanylate cyclase system.
Intraglomerular deposition of coagulation-fibrinolysis factors and a platelet membrane antigen in various glomerular diseases.
The intraglomerular location of coagulation-fibrinolysis factors (CFF) and a platelet membrane antigen (glycoprotein IIb-IIIa; GPIIb-IIIa) was determined in 101 patients with various glomerular diseases. Renal biopsy specimens were examined by immunofluorescence microscopy, using antisera against fibrinogen/fibrin reactive antigen (FRA), cross-linked fibrin degradation products (XL-FDP), fibronectin (FN), factor XIII-subunit a (F-XIIIa), plasminogen (Plg), alpha 2-plasmin inhibitor (alpha 2-PI) and GPIIb-IIIa. Intraglomerular deposits of the CFF were found at high rates in patients with IgA glomerulonephritis (GN), membranous nephropathy (MN) and lupus GN. The coexistence of deposits of these factors was ascertained by the double-staining method. The deposition rates of XL-FDP and GPIIb-IIIa were very low in patients with minimal-change nephrotic syndrome and focal glomerulosclerosis. Some cases of diabetic glomerulosclerosis (DGS) showed CFF deposition. FRA deposits associated with F-XIIIa and FN may indicate the presence of the cross-linked fibrin. Furthermore, the presence of Plg deposits together with alpha 2-PI and XL-FDP suggests the deposition of fibrin followed by fibrinolysis, but not of fibrinogen, and the coexistence of GPIIb-IIIa suggests the involvement of platelets in the reactions. These studies provide evidence that stabilized fibrin deposition with subsequent fibrinolysis and platelet activation take place in glomeruli in a fairly large proportion of patients with IgA GN, MN and lupus GN and in some cases of DGS.
Intracellular chloride activity of rabbit proximal straight tubule perfused in vitro.
To examine the cellular mechanism of Cl- transport in the proximal tubule, cell Cl- activity (aiCl) was measured with double-barreled Cl(-)-selective microelectrodes in the rabbit proximal straight tubules (PST) perfused in vitro. When tubules were perfused and bathed with ultrafiltrate-like solution, aiCl (corrected for the interference from undetermined intracellular anions, 4.2 mM) was 17.8 +/- 0.5 mM (n = 90), and this value was 1.3 times higher than that predicted from passive distribution (basolateral membrane potential, Vbl = -51.9 +/- 0.8 mV). Reducing either luminal or bath Cl- indicated that the basolateral membrane plays a more important role as a determinant of aiCl. aiCl reduction rates induced by luminal Cl- removal was inhibited by 75% by 1 mM SITS added to the lumen but was not inhibited by furosemide (0.1 mM). Application of SITS in the lumen in the control condition, however, did not change aiCl appreciably. Reducing the luminal HCO3- from 25 to 5 mM did not significantly change aiCl or Vbl. Replacing luminal Na+ with choline decreased aiCl but these effects were still present when luminal Cl- was absent. We conclude that in the rabbit PST: 1) Cl- is taken up into the cell against the electrochemical gradient, 2) the basolateral membrane plays a more important role in the regulation of aiCl, and 3) luminal Cl- transport is SITS sensitive and Na+ independent.
Plasma levels of human atrial natriuretic factor in patients treated by hemodialysis and continuous ambulatory peritoneal dialysis.
We measured plasma levels of immunoreactive human atrial natriuretic factor (ANF) in chronic renal failure patients treated by hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). Predialysis plasma ANF was significantly higher in HD patients (271.8 +/- 173.4 pg/ml) as compared to CAPD patients (81.8 +/- 80.5 pg/ml) and healthy subjects (31.5 +/- 19.8 pg/ml). Plasma volume was higher in HD patients than in CAPD patients. Plasma ANF and plasma volume showed a significant positive correlation. In HD patients, high plasma ANF value decreased significantly to a value comparable with that of CAPD patients after each dialysis. The removal rates of ANF by HD and CAPD were comparable. Ultrafiltration corresponding to 2% of body weight without dialysis also reduced plasma ANF. Thus, the difference in plasma ANF values between HD and CAPD patients seems to be mostly due to the difference in plasma volume, indicating that plasma ANF is sensitive to volume status even in chronic dialysis patients.
KCl co-transport across the basolateral membrane of rabbit renal proximal straight tubules.
Mammalian renal proximal tubules reabsorb large amounts of chloride. Mechanisms of the transcellular chloride transport are poorly understood. To determine whether KCl co-transport exists in the basolateral membrane of mammalian renal proximal tubule, isolated rabbit proximal straight tubules (S2 segment) were perfused in vitro, and intracellular activities of potassium and chloride (aKi, aCli) were measured by double-barreled ion-selective microelectrodes. aCli did not change when basolateral membrane voltage was altered by application of a direct current through perfusion pipette. aCli changes in response to bath chloride elimination were not affected by current application as well, indicating that the basolateral chloride transport is electroneutral. An increase in potassium concentration of the bath fluid from 5 to 20 mM reversibly increased aCli by 10 mM. This response of aCli to a change in the bath potassium concentration was also observed when luminal chloride was removed, or ambient sodium was totally removed. aKi significantly decreased by 5 mM when chloride was removed from the bath. These data demonstrate the existence of an electroneutral Na+-independent KCl co-transport in the basolateral membrane of the rabbit proximal tubule. Calculated electrochemical driving force was favorable for the movement of KCl from the cell to the peritubular fluid.
Interaction of chloride and bicarbonate transport across the basolateral membrane of rabbit proximal straight tubule. Evidence for sodium coupled chloride/bicarbonate exchange.
The existence of chloride/bicarbonate exchange across the basolateral membrane and its physiologic significance were examined in rabbit proximal tubules. S2 segments of the proximal straight tubule were perfused in vitro and changes in intracellular pH (pHi) and chloride activity (aCli) were monitored by double-barreled microelectrodes. Total peritubular chloride replacement with gluconate increased pHi by 0.8, and this change was inhibited by a pretreatment with an anion transport inhibitor, SITS. Peritubular bicarbonate reduction increased aCli, and most of this increase was lost when ambient sodium was totally removed. The reduction rates of pHi induced by a peritubular bicarbonate reduction or sodium removal were attenuated by 20% by withdrawal of ambient chloride. SITS application to the bath in the control condition quickly increased pHi, but did not change aCli. However, the aCli slightly decreased in response to SITS when the basolateral bicarbonate efflux was increased by reducing peritubular bicarbonate concentration. It is concluded that sodium coupled chloride/bicarbonate exchange is present in parallel with sodium-bicarbonate cotransport in the basolateral membrane of the rabbit proximal tubule, and it contributes to the basolateral bicarbonate and chloride transport.
Giant serpentine aneurysm in a long-term hemodialysis patient.
A long-term hemodialysis patient with a giant intracranial vascular channel, which has been called a giant serpentine aneurysm, is presented. A 50-year-old man with an eight-year history of hemodialysis treatment was admitted because of headache, nausea and double vision. Computed tomographic scans and nuclear magnetic resonance revealed intracranial abnormal shadow. The left vertebral arteriography showed that the distal portion of the left vertebral artery was dilated to 17 mm in diameter. The basilar artery showed a large tortuous vascular channel and globular aneurysms over 25 mm in diameter. This giant serpentine aneurysm is a rather rare disease. To our knowledge, it has not been reported as a complication in a hemodialysis patient, although fourteen cases have been reported in the literature. In our case, several conditions such as long-term hypertension, hyperlipidemia, hypercalcemia, atherosclerosis and abnormal blood flow due to arteriovenous fistula for hemodialysis treatment might be considered to play a role in the formation of the giant serpentine aneurysms.
Generation of pH gradient across the rabbit collecting duct segments perfused in vitro.
Ability of pH gradient generation was examined in three segments of rabbit collecting duct, cortical collecting duct (CCD), outer medullary collecting duct (OMCD) and inner medullary collecting duct (IMCD). These segments were perfused in vitro, and the steady-state luminal pH in stop-flow condition (pHs) and the electrochemical potential difference of H+ (EH) were determined using double-barreled liquid membrane pH microelectrode punctured into the lumen. In CCD, pHs was 7.71 +/- 0.08 in normal rabbits, 7.72 +/- 0.08 in DOCA-treated rabbits and 7.27 +/- 0.05 in starved rabbits, while peritubular fluid was kept at pH 7.5 EH (positive value means H+ accumulation in the lumen above electrochemical equilibrium) was -15.3 +/- 5.2, -31.3 +/- 3.7 and 10.3 +/- 3.1 mV, respectively. Peritubular acidification (peritubular pH 6.8) by reducing HCO3-concentration decreased pHs, but increased its negativity of EH in all groups. In OMCD pHs was 6.57 +/- 0.08 in normal, 6.58 +/- 0.11 in DOCA-treated and 6.47 +/- 0.12 in starved animals. EH was 54.5 +/- 4.6, 57.7 +/- 6.8 and 64.2 +/- 6.9 mV, respectively. Peritubular acidification lowered pHs further, 5.51 +/- 0.07, 5.67 +/- 0.16 and 5.41 +/- 0.19, respectively. EH was enhanced in all groups. In IMCD pHs was 7.36 +/- 0.04 with EH being 6.8 +/- 2.9 mV, and peritubular acidification did not generate pH gradient. These data suggest that the generation of a steep acid pH gradient is mainly due to OMCD. Luminal alkalinization predominated in CCD except in starved rabbits. IMCD did not generate appreciable pH gradient.(ABSTRACT TRUNCATED AT 250 WORDS)
Effect of vasopressin on Na+-K+-ATPase activity in rat cortical collecting duct.
Vasopressin (V) causes a sustained increase in Na reabsorption and K secretion in isolated cortical collecting ducts (CCD) from rats. Because increased Na reabsorption may be associated with increased Na+-K+-ATPase activity, we investigated effects of V, given either in vivo or in vitro, on Na+-K+-ATPase activity in isolated nephron segments of rats. Na+-K+-ATPase activities were measured by coupling the hydrolysis of ATP to the production of a fluorescent nucleotide. In addition to CCD, other microdissected structures were medullary thick ascending limbs of Henle's loop, cortical thick ascending limbs of Henle's loop, and outer medullary collecting duct. To determine the time course of the response, Na+-K+-ATPase activities were measured in CCD 1 h, 3 h, 1 day, 3 days, and 7 days after intramuscular administrations of V. There was a significant increase in Na+-K+-ATPase activity in CCD after in vivo V administration for 7 days but not in any other segment. The activities increased after 3 days of administration of V. For in vitro experiments, CCD were incubated with 10(-6) M V for 1-3 h. Na+-K+-ATPase activities did not change after 1- or 3-h exposure of V in CCD in vitro. We conclude that prolonged V administration in vivo increases Na+-K+-ATPase activity in CCD. Because, in vitro exposure to V does not increase Na+-K+-ATPase activity, we conclude that rapid V-dependent increases in Na and K transport previously demonstrated in isolated perfused tubules are not dependent on a change in maximal Na+-K+-ATPase activity.
Ten years' survey of dialysis-associated tuberculosis.
Tuberculosis associated with dialysis was studied at the Renal Unit of the Tokyo Medical and Dental University and Yokosuka Mutual Aid Hospital Kidney Center, in both of which the treatments of chronic renal failure are the same. There are 12 tuberculosis patients out of 367 patients on maintenance hemodialysis from January 1967 to December 1976, an incidence of 3.3%. This was 6-16 times greater than that in the general population of this country according to yearly statistics. The characteristics of dialysis-associated tuberculosis include a high incidence of miliary tuberculosis, especially in aged patients and difficulty in establishing the diagnosis before death. Clinical features which are helpful in the early diagnosis are intermittent high fever of unknown origin, weight loss, anorexia, abnormalities of the central nervous system, erythrocyte sedimentation rate over 100 mm/h, leukocytosis and high value of the C-reactive protein. With the increasing number of dialysis patients, an increase of dialysis-associated tuberculosis is expected and this will be one of the major problems of dialysis patients in future.
Reduction of unfavourable effects of heparin with use of gabexate mesilate in dialysis.
Gabexate mesilate (GM), a potent synthetic proteinase inhibitor has been evaluated as an alternative anticoagulant to heparin for haemodialysis. GM haemodialysis was achieved at a dose of 1,600mg/hr. GM was found to be dialysable and so rapidly degraded that dialysis with GM anticoagulation was analogous to regional heparinisation. Although heparin induced considerable lipolytic activity, GM showed no particular effect on lipids. Some patients reported mild nausea and there was evidence of slight clot formation around the top of the venous drip chamber. GM anticoagulation is easier than the conventional unreliable techniques of regional heparinisation.
[Appropriate dialysis for individual patient - on the "dialysis minimum"].
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