Yoshiaki Kondo

Nihon University, Edo, Tōkyō, Japan

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Publications (35)116.77 Total impact

  • Nephrology 05/2013; 18(5):390-1. · 1.69 Impact Factor
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    ABSTRACT: Clinicians often need access to electronic information resources that answer questions that occur in daily clinical practice. This information generally comes from publicly available resources. However, clinicians also need knowledge on institution-specific information (e.g., institution-specific guidelines, choice of drug, choice of laboratory test, information on adverse events, and advice from professional colleagues). This information needs to be available in real time. This study characterizes these needs in order to build a prototype hospital information system (HIS) that can help clinicians get timely answers to questions. We previously designed medical knowledge units called Medical Cells (MCs). We developed a portal server of MCs that can create and store medical information such as institution-specific information. We then developed a prototype HIS that embeds MCs as links (MCLink); these links are based on specific terms (e.g., drug, laboratory test, and disease). This prototype HIS presents clinicians with institution-specific information. The HIS clients (e.g., clinicians, nurses, pharmacists, and laboratory technicians) can also create an MCLink in the HIS using the portal server in the hospital. The prototype HIS allowed efficient sharing and use of institution-specific information to clinicians at the point of care. This study included institution-specific information resources and advice from professional colleagues, both of which might have an important role in supporting good clinical decision making.
    Journal of Medical Systems 08/2012; 37(4):9956. · 1.78 Impact Factor
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    ABSTRACT: To clarify whether the double product (DP) (product of systolic blood pressure (SBP) and pulse rate (PR)) at rest based on home blood pressure (HBP) measurement has prognostic value for mortality. HBP data of 2,583 participants from a Japanese general population (40% men) ≥35 years of age (mean, 59 years) without a history of cardiovascular disease (CVD) were obtained. The prognostic significance for a 1,000 mm Hg × beats/min elevation in the DP was determined by Cox proportional hazard regression analysis. The association between mortality and the DP was compared to that between mortality and the SBP or the PR using the likelihood ratio (LR) test. During a mean follow-up of 12.0 years, 454 total deaths, 153 CVD deaths (85 cardiac diseases, 68 strokes), and 301 non-CVD deaths occurred. The DP was positively and significantly associated with total, CVD, cardiac, stroke, and non-CVD mortality. The LR test showed that the DP was more strongly associated with total mortality, mortality from cardiac disease, and non-CVD than SBP. Similarly, the DP was more strongly associated with total death, CVD death, and death from stroke than PR. The home DP was significantly associated with mortality, and the LR test indicated that the association between the DP and mortality would be stronger than that between mortality and SBP or PR. These findings are preliminary, and further study is needed to confirm the usefulness of the DP in risk stratification.
    American Journal of Hypertension 02/2012; 25(5):568-75. · 3.67 Impact Factor
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    ABSTRACT: With the growth in the popularity of the Internet, individuals' skills in finding and applying information about health issues [health literacy (HL)] are affecting their health behaviors. This study aimed to examine functional HL (FHL), critical HL (CHL), and hypertension knowledge (HK) among middle-aged Japanese adults. In addition, to measure health outcomes, we examined the relationship between HL, HK, and blood pressure (BP) level. The study included middle-aged participants who received an annual health check-up at an urban clinic in Japan. FHL, CHL, and HK were assessed using structured questionnaires. In addition, BP was obtained from the electronic medical record. Participants included 139 women and 181 men with a mean age of 54.4 years (standard deviation = 0.69). Individuals with lower reading comprehension scores in FHL were more likely to have a history of hypertension (P = 0.003) and diabetes mellitus (P = 0.02). Individuals with lower CHL had significantly higher rates of current smoking (P = 0.03) and men with lower CHL had a significantly higher waist circumference (P = 0.03). There was a significant relationship between sex and HK (P = 0.03). Systolic BP in women with higher HL and HK was significantly lower than in men with higher FHL (P < 0.001), CHL (P = 0.01), and HK (P = 0.001). Lower HL and HK were associated with a poor health status and BP level in middle-aged participants. Further research is needed to examine the role of health management in improving outcomes and to address disparities between individuals with higher and lower HL.
    Blood pressure monitoring 08/2011; 16(5):224-30. · 1.62 Impact Factor
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    ABSTRACT: Barttin, a gene product of BSND, is one of four genes responsible for Bartter syndrome. Coexpression of barttin with ClC-K chloride channels dramatically induces the expression of ClC-K current via insertion of ClC-K-barttin complexes into plasma membranes. We previously showed that stably expressed R8L barttin, a disease-causing missense mutant, is retained in the endoplasmic reticulum (ER) of Madin-Darby canine kidney (MDCK) cells, with the barttin β-subunit remaining bound to ClC-K α-subunits (Hayama A, Rai T, Sasaki S, Uchida S. Histochem Cell Biol 119: 485-493, 2003). However, transient expression of R8L barttin in MDCK cells was reported to impair ClC-K channel function without affecting its subcellular localization. To investigate the pathogenesis in vivo, we generated a knockin mouse model of Bartter syndrome that carries the R8L mutation. These mice display disease-like phenotypes (hypokalemia, metabolic alkalosis, and decreased NaCl reabsorption in distal tubules) under a low-salt diet. Immunofluorescence and immunoelectron microscopy revealed that the plasma membrane localization of both R8L barttin and the ClC-K channel was impaired in these mice, and transepithelial chloride transport in the thin ascending limb of Henle's loop (tAL) as well as thiazide-sensitive chloride clearance were significantly reduced. This reduction in transepithelial chloride transport in tAL, which is totally dependent on ClC-K1/barttin, correlated well with the reduction in the amount of R8L barttin localized to plasma membranes. These results suggest that the major cause of Bartter syndrome type IV caused by R8L barttin mutation is its aberrant intracellular localization.
    AJP Renal Physiology 05/2011; 301(2):F297-307. · 4.42 Impact Factor
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    ABSTRACT: The effect of Ca(2+) and calcimimetics on NaCl transport was investigated in the in vitro isolated microperfused mouse thin ascending limb of Henle's loop. In the presence of a transmural NaCl gradient, the transepithelial diffusional potential was 13.7 +/- 0.4 mV (n = 17). When the Ca(2+) in the bath was increased from 1.5 to 4.5 mM at 37 degrees C, the relative permeability of Na(+) to Cl(-) (P (Na) /P (Cl)) estimated from the diffusional voltage deflection due to the transepithelial NaCl gradient (V (d)) changed from 0.371 +/- 0.017 to 0.341 +/- 0.015 (n = 10, P < 0.0001). When the Ca(2+) in the lumen was increased from 1.5 to 4.5 mM, the P (Na) /P (Cl) decreased from 0.349 +/- 0.013 to 0.330 +/- 0.013 (n = 5, P < 0.002). The addition of 0.1 mM neomycin and 0.2 mM gentamicin to the bath or lumen also decreased the P (Na) /P (Cl). The same effect on P (Na) /P (Cl) of Ca(2+) and calcimimetics occurred in ClC-K1 (kidney-specific chloride channel) knockout mice. The addition of 300 mug/ml protamine to the bath strongly inhibited changes to P (Na) /P (Cl) induced by basolateral Ca(2+). These data indicate that ambient Ca(2+) and calcimimetics inhibit Na(+) transport in the thin ascending limb, which is known to occur via the paracellular shunt pathway. Our observations strongly suggest that Ca(2+) is involved in the regulation of paracellular Na(+) permeability in the thin ascending limbs.
    Pflügers Archiv - European Journal of Physiology 06/2010; 460(1):197-205. · 4.87 Impact Factor
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    ABSTRACT: The purpose of this prospective cohort study was to investigate associations between stroke and blood pressure (BP) indices (systolic BP [SBP], diastolic BP [DBP], mean BP, and pulse pressure [PP]) determined by home BP measurement. Associations between stroke and BP indices were examined in a rural Japanese population. Home BP data of 2369 subjects (40% men) > or =35 years of age (mean, 59 years) without a history of stroke were obtained. Associations between stroke and each index were determined using Cox proportional hazards regression and the likelihood ratio (LR) test. During follow-up (mean, 11.7 years), 238 strokes occurred. The LR test showed that SBP and mean BP were significantly more strongly associated with total and ischemic stroke than DBP and PP (LR chi2 > or =9.3, P<0.01 for SBP/mean BP, LR chi2 < or =3.8, P> or =0.05 for DBP/PP). SBP tended to be more strongly associated with total/ischemic stroke than mean BP (LR chi2=3.8, P=0.05 for SBP, LR chi2 < or =0.2, P>0.6 for mean BP). PP tended to be slightly more strongly associated with ischemic stroke than DBP (LR chi2=7.5, P<0.01 for DBP, LR chi(2)=9.3, P<0.01 for PP), whereas DBP was significantly more strongly associated with hemorrhagic stroke than PP (LR chi2=9.2, P<0.01 for DBP, LR chi2=2.5, P=0.01 for PP). PP obtained from home BP measurements was weakly associated with stroke, whereas SBP showed the strongest association. Additionally, DBP and PP may be associated with different stroke types.
    Stroke 05/2009; 40(8):2859-61. · 6.16 Impact Factor
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    ABSTRACT: The factors that affect physicians' prescribing remain unclear. Although previous reports suggest that prescription decisions are associated with various clinical situation, most of these studies analyzed simulated patient models rather than actual clinical practice. Here, we retrospectively analyzed actual cases of statin prescription for hyperlipidemia at Tohoku University Hospital between Apr 1, 2004 and Mar 31, 2008. Twelve physicians (6 cardiologists, 3 nephrologist, and 3 diabetologist) made decisions on whether to prescribe statins to 187 patients in 788 visits. As expected, cardiologists started prescribing statins at significantly lower serum total cholesterol levels than other specialists (221.7mg/dL vs. 244.7mg/dL, P<0.05). Interestingly, the total cholesterol levels that triggered prescribing differed significantly among cardiologists (p<0.05). These results suggested that prescription decisions differed not only among specialties but also among individuals.
    AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium 01/2009; 2009:604-8.
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    ABSTRACT: K(+) channels permit more than one ion within their conducting pathway at any given moment and show a saturating single-file behavior. The conduction of Rb(+) shows an unusual behavior, a so-called "Rb(+) anomaly," and it has been used to probe the mechanism of the ion conduction through K(+)-selective channels. Under the bi-ionic condition of K(+) and Rb(+), we carried out patch-clamp single-channel current measurements in MaxiK(+) channels from mouse submandibular acinar cells. Keeping only K(+) on one side of the membrane while varying fractional Rb(+) concentration on the opposite, we had a series of current-voltage relationships. It showed a characteristic inflection at which the ion conductance was divided into two components, one ascribed to pure K(+) conduction and the other to K(+) and Rb(+) bi-ionic conduction. By analyzing the latter, we depicted that (1) the bi-ionic conductance showed a characteristic reduction curve as the Rb(+) fractional concentration increased; (2) Rb(+) can bind the channel more tightly when it accesses from the outside than from the inside. Thus we conclude that such asymmetry of the Rb(+) binding determines the pattern of bi-ionic conductance reduction in K-selective channels.
    The Journal of Physiological Sciences 11/2008; 58(6):363-9. · 1.09 Impact Factor
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    ABSTRACT: Recently, disorders of the slit diaphragm have been considered as major causes of proteinuria in renal disease and the charge barrier function of the glomerular capillary wall has been given less attention. We evaluated the charge selectivity index (CSI) in 40 patients with podocyte disease (PD), 75 with chronic glomerulonephritis (CGN), and 8 with Dent disease, to reexamine the charge barrier function. We evaluated CSI in Dent disease because the urinary protein profile in Dent disease was assumed to be a concentrate of a normal glomerular filtrate. CSI was defined as the renal clearance ratio between IgA and IgG. CSI values (mean +/- SD) in the CGN and PD groups and in Dent disease were 1.12 +/- 0.25, 0.42 +/- 0.31, and 0.16 +/- 0.06, respectively, suggesting that the charge barrier function was defective in the CGN group and of reduced capacity in the PD group. The results suggest that functional interactions between the slit diaphragm and the glomerular basement membrane exist, and that a slit diaphragm disorder is accompanied by a decrease in the charge barrier function in PD, as argued by the conventional hypothesis.
    Pediatric Nephrology 11/2008; 24(3):609-12. · 2.94 Impact Factor
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    ABSTRACT: The calcium-sensing receptor (CaSR) is known well as a sensor of extracellular calcium for regulating parathyroid hormone secretion. CaSR is located along all nephron segments in the kidney. While hypercalcemia strongly enhances urinary acidification, the relationship between CaSR and acid-base metabolism in the kidney is still uncertain. In the present study, we examined whether CaSR activation caused acid secretion in the medullary thick ascending limb (mTAL), which is one of the major nephron segments involved in both mineral and acid-base regulation. The effects of a potent calcimimetic neomycin (Neo) on intracellular pH (pHi) were analyzed in the in vitro miroperfused mouse mTALs. The mTALs were incubated with 2,7-bis-(2-carboxyethyl)-5(6)-carboxyfluoresceine-acetoxymethylester (BCECF-AM) for microfluorescent pHi measurements. In HCO(3)(-)/CO(2)-buffered solution, the steady-state pHi was 7.17 +/- 0.01 (n = 19). Basolateral Neo at 0.4 mM in basolateral side significantly alkalinized the mTAL cells to 7.28 +/- 0.02 (n = 19), while Neo in the lumen had no effect on pHi. Neo in the basolateral side alkalinized the mTALs in the absence of ambient Na(+) and the presence of H(+)-ATPase inhibitor bafilomycin in the lumen, indicating that the effect of Neo is unrelated to Na(+)-dependent acid-base transporters such as Na(+)-H(+) exchangers and Na(+)-HCO(3)(-) cotransporter, or to luminal H(+)-ATPase. In contrast, the effect of Neo on pHi was inhibited by K(+) removal or treatment with specific H(+)-K(+)-ATPase (HKa) inhibitors, ouabain and Sch-28080, in the lumen. Our results suggest that hypercalcemia induces urinary acidification partly by stimulating luminal K(+)-dependent H(+)-excretion via CaSR in mouse mTALs.
    The Tohoku Journal of Experimental Medicine 10/2008; 216(1):7-15. · 1.37 Impact Factor
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    ABSTRACT: HOMED-BP study aims to establish an optimal target blood pressure (BP) level based on BP values self-measured at home (home BP), supported by information technology. Subjects are automatically randomized to either more intensive BP-lowering group or less intensive one and to regimens based on one of three initial drugs. BP values are collected via the Internet and study database is automatically updated. The study has started since 2001 and 1953 patients participate in the study.
    AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium 02/2008;
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    ABSTRACT: We designed an information management and sharing system using the Medical Cells(MCs), which clinicians can use to share appropriate medical information. This system enables the authorized users to create, edit and search clinical knowledge content directly from portal site. In this system, we assessed clinicians' impact and satisfaction with their use of the MCs. The MCs had a significant impact on clinical knowledge management.
    AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium 02/2008;
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    ABSTRACT: Enlarged cardiothoracic ratio (CTR) in chest X-ray is related to cardiac dysfunction. We developed a software program that provided an automated measurement of CTR from chest X-ray image files. With high accuracy, CTR was calculated from chest X-ray images taken in outpatient clinics. It may be helpful for physicians to reduce routine work and to detect latent heart disease.
    AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium 02/2008;
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    ABSTRACT: To investigate the risk of stroke in subjects with isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and combined systolic and diastolic hypertension (SDH) in a Japanese general population, we used 24-h ambulatory blood pressure (ABP) and casual-screening blood-pressure (CBP) readings. Subtypes of hypertension were defined based on systolic blood pressure (SBP) >135 mm Hg or diastolic blood pressure (DBP) >80 mm Hg for 24-h ABP, and SBP >140 mm Hg or DBP >90 mm Hg for CBP. We obtained 24-h ABP and CBP data for 1271 (40% male) subjects aged > or =40 years (mean age, 61 years) without a history of symptomatic stroke; their stroke-free survival was then determined. The prognostic significance of each subtype of hypertension was determined by Cox proportional hazard analysis. There were 113 symptomatic strokes during follow-up (mean time, 11 years). Compared with normotension, among the hypertension subtypes determined by 24-h ABP, the adjusted relative hazards (RHs) of stroke were 2.24 for ISH (P = .002) and 2.39 for SDH (P = .0004). The association was less marked among subtypes determined by CBP (RH = 1.40 and P = .13 for ISH; RH = 2.07 and P = .017 for SDH). The IDH group was excluded from the Cox analysis because both the prevalence and the number of events were low in this group. Isolated systolic hypertension, as determined by 24-h ABP measurements, was associated with a high risk of stroke, similar to that found in SDH subjects; this suggests that the prognosis of hypertensive patients would be improved by focusing treatment on 24-h systolic ABP.
    American Journal of Hypertension 11/2007; 20(10):1125-31. · 3.67 Impact Factor
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    ABSTRACT: WNK1 and WNK4 mutations have been reported to cause pseudohypoaldosteronism type II (PHAII), an autosomal-dominant disorder characterized by hyperkalemia and hypertension. To elucidate the molecular pathophysiology of PHAII, we generated Wnk4(D561A/+) knockin mice presenting the phenotypes of PHAII. The knockin mice showed increased apical expression of phosphorylated Na-Cl cotransporter (NCC) in the distal convoluted tubules. Increased phosphorylation of the kinases OSR1 and SPAK was also observed in the knockin mice. Apical localization of the ROMK potassium channel and transepithelial Cl(-) permeability in the cortical collecting ducts were not affected in the knockin mice, whereas activity of epithelial Na(+) channels (ENaC) was increased. This increase, however, was not evident after hydrochlorothiazide treatment, suggesting that the regulation of ENaC was not a genetic but a secondary effect. Thus, the pathogenesis of PHAII caused by a missense mutation of WNK4 was identified to be increased function of NCC through activation of the OSR1/SPAK-NCC phosphorylation cascade.
    Cell Metabolism 06/2007; 5(5):331-44. · 14.62 Impact Factor
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    ABSTRACT: To examine whether the functional and morphologic conversion of the neonatal ascending thin limb (ATL) of Henle's loop is related to gestational length, we evaluated the transepithelial voltages (Vts) of ATLs in perinatal mouse, hamster, rabbit, and rat kidneys. In isolated microperfused tubule preparations, Vts of neonatal ATLs were 23.8 +/- 1.4 in mouse, 25.7 +/- 2.2 in hamster, and 18.2 +/- 1.6 mV in rabbit. The influence of gestational length on the Vts and rat Na-K-Cl cotransporter (rNKCC2) expression pattern was also examined in perinatal rats subjected to a prolonged gestation due to either a daily s.c. injection of 5 mg progesterone or ligation of the extremities of the uterine horn. Vts of d 3 neonates were 2.9 +/- 1.0 (p < 0.0001 versus d 0); Vts of d 23 fetuses subjected to ligation were 4.9 +/- 0.8 (p < 0.005 versus d 0); and Vts of d 23 fetuses given progesterone were 3.4 +/- 1.7 mV (p < 0.001 versus d 0). rNKCC2 expression tended to disappear in the renal papillae of d 23 fetuses. Our data demonstrate that the perinatal conversion of the ATL is a phenomenon commonly observed among rodents; furthermore, it is dependent on the gestational length, but unrelated to the birth process.
    Pediatric Research 03/2007; 61(2):171-5. · 2.67 Impact Factor
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    ABSTRACT: Clinical data consist of a wide variety of information. Database software that covers all types of clinical data is ideal. Patient data in cardiology were converted into an XML-format by tags that cardiologist selected. The structure of the database was comprehensible to the cardiologists. The arbitrary queries to the database from the end-users were captured with a resultant high satisfaction.
    AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium 02/2007;
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    ABSTRACT: The authors previously designed managing and sharing medical information units called "Medical Cells". The authors measured clinicians' satisfaction with the Medical Cells, and experiences with the performance of the Medical Cells within an existing electronic medical record system. The Medical Cells were useful in obtaining correct medical knowledge, and had a significant impact on managing and sharing medical information within the EMRS.
    AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium 02/2007;
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    ABSTRACT: The extracellular calcium-sensing receptor (CaSR) located in either luminal or basolateral cell membranes of various types of renal tubules including proximal tubules, Henle's loop and collecting ducts has been thought to play a fundamental role in electrolyte metabolism. To further identify the physiological roles of the CaSR, we examined the effects of Ca(2+) and calcimimetics neomycin (Neo), gentamicin and gadolinium chloride (Gd(3+)) on the intracellular pH (pHi) of in vitro microperfused mouse medullary thick ascending limb (mTAL) cells of Henle's loop, by loading the cells with fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein and measuring the ratio of fluorescence emission at 530 nm after exciting the dye at 490 and 440 nm. In a steady-state condition in Hepes-buffered solution, the pHi in the mTALs was 7.29 +/- 0.04 (n = 9). A concentration of 200 micromol/l Neo in the basolateral side decreased the pHi after 1 min by -0.13 +/- 0.02 (n = 34, p < 0.0001). The other calcimimetics showed similar effects on pHi, whereas none of these calcimimetics in the lumen affected pHi. Na(+) removal or the inhibition of Na(+) and proton transport with amiloride, bumetanide, or bafilomycin did not eliminate the effect of Neo on pHi. On the other hand, Cl(-) removal clearly eliminated the Neo-induced pHi decrease (-0.06 +/- 0.01 vs -0.00 +/- 0.05 in Cl(-) removal, n = 4, p < 0.003). Thus, we have demonstrated for the first time that the CaSR is involved in the regulation of the pHi in the mTAL and requires Cl(-) to exert its effect.
    The Tohoku Journal of Experimental Medicine 01/2007; 210(4):291-300. · 1.37 Impact Factor