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Meguro-ku, Japan

Aruga S.,Tokyo Kyosai Hospital
Clinical calcium | Year: 2011

Patients with urolithiasis have been increasing in the world, especially morbidity of calcium nephrolithiasis has been increasing in the advanced countries. The changes in the environmental factors including alternation of diet are said to be associated with the increment of morbidity of kidney stone. Idiopathic hypercalciuria is one of the most important risk factor of calcium nephrolithiasis and is classified into absorptive, resorptive, and renal leak. Though the origins of these three types of hypercalciuria are different, increased bone resorption and increased calcium absorption from gut tend to be observed simultaneously. Not only genetic abnormalities in the proteins which are involved in calcium metabolisms but environmental factors such as high sodium intake and chronic acid load caused by increased ingestion of animal protein have been considered to be associated with increased urinary calcium excretion. Renal metabolisms of oxalate and phosphate which are important compositions of calcium containing stone, uric acid as a promoter and citrate as a inhibitor of nephrolithiasis are also described.

Kanda E.,Tokyo Kyosai Hospital | Kanda E.,Tokyo Medical and Dental University | Ai M.,Tokyo Medical and Dental University | Yoshida M.,Tokyo Medical and Dental University | Shiigai T.,Shiigai Clinic
American Journal of Nephrology | Year: 2014

Background/Aims: Non-volatile acid is produced by metabolism of organic sulfur in dietary protein, and promotes kidney damage. We investigated the role of dietary acid load, in terms of net endogenous acid production (NEAP), in chronic kidney disease (CKD) progression. Methods: 217 CKD patients on low-protein diet with a normal serum bicarbonate level were enrolled in this retrospective cohort study in Japan. The primary outcome was 25% decline in estimated glomerular filtration rate (eGFR) or start of dialysis. Their NEAP was measured every 3 months. The patients were categorized into four groups on the basis of quartiles of NEAP every 3 months. The groups were treated as time-dependent variables. Results: The average age (SD) was 70.6 (7.1) years; eGFR 23.5 (14.2) ml/min/1.73 m2. Analysis using extended Cox models for the NEAP groups adjusted for baseline characteristics (referring to group 1 showing the lowest NEAP) showed that high NEAP was associated with a high risk of CKD progression; group 2, adjusted hazard ratio (HR) 3.930 (95% confidence interval (CI) 1.914, 8.072); group 3, adjusted HR 4.740 (95% CI 2.196, 10.288); group 4, adjusted HR 4.303 (95% CI 2.103, 8.805). Logistic regression analysis adjusted for baseline characteristics showed that the occurrence of hypoalbuminemia or hyperkalemia was associated with low serum bicarbonate level and the presence of complications at baseline, but not with NEAP. Conclusion: In elderly CKD patients, our findings suggest that high NEAP is independently associated with CKD progression. The decrease in NEAP may be an effective kidney-protective therapy. © 2014 S. Karger AG, Basel.

Nakajima K.,Josai University | Oda E.,Medical Check up Center | Kanda E.,Tokyo Kyosai Hospital
Blood Pressure | Year: 2016

Background. High serum sodium (sNa) concentrations may be associated with hypertension, which deteriorates kidney function. However, it is equivocal whether high sNa concentrations are associated with impaired kidney function independently of blood pressure (BP) or serum chloride (sCl). Therefore, we addressed this issue in an apparently healthy population. Methods. Clinical variables including estimated glomerular filtration rate (eGFR) were examined in 3603 men and women (aged 25-75 years) who underwent health-screening check-ups. sNa concentrations were classified into five categories. Results. Most parameters, including age and BP, increased with increasing sNa, whereas eGFR decreased. Logistic regression analysis showed that, compared with low-normal sNa (≤ 140 mEq/l), high sNa (≥ 144 mEq/l) was significantly associated with elevated BP (≥ 130/85 mmHg) even after adjustment for blood hematocrit, eGFR, serum potassium (sK) concentration and sCl. The highest sNa category was significantly associated with reduced eGFR (< 60 ml/min/1.73 m2) independently of elevated BP. Unlike adjustment for sK, adjustment for sCl strengthened the association between high sNa and elevated BP but attenuated the association between high sNa and reduced eGFR. Conclusions. These results suggest that high sNa concentrations, even within the normal range, are independently associated with elevated BP and impaired kidney function. These associations may be substantially modified by sCl. © 2015 Scandinavian Foundation for Cardiovascular Research.

Nakajima K.,Josai University | Oda E.,Medical Check up Center | Kanda E.,Tokyo Kyosai Hospital
Scandinavian Journal of Clinical and Laboratory Investigation | Year: 2016

Low urine pH, a plausible predictor for chronic kidney disease and metabolic disorders, is often observed in obese individuals. However, the association between low urine pH and low body weight is equivocal. We examined clinical parameters including urine pH and body mass index (BMI) in a cross-sectional study of 3629 apparently healthy Japanese adults aged 25-80 years who underwent a health-screening check-up. Urine pH was lower and the prevalence of proteinuria was significantly higher in subjects with BMI of ≥27.0 kg/m2 compared with those with BMI of 21.0-22.9 kg/m2. By contrast, hematuria was more prevalent in subjects with BMI of ≤ 20.9 kg/m2. Logistic regression analysis showed that BMI of ≥27.0 kg/m2 was significantly associated with low urine pH (≤ 5.5), which remained significant after adjustment for relevant confounders including age, sex, proteinuria, estimated glomerular filtration rate, urine density, hematuria, smoking status, and daily alcohol drinking. However, the association disappeared after further adjustment for serum uric acid. In contrast, the association between low urine pH and BMI of ≤19.0 kg/m2 was significant after adjustment for age and sex and rather strengthened by the further adjustment for serum uric acid. In conclusion, low urine pH may be independently associated with low BMI. However, the underlying mechanisms of low urine pH in low body weight may differ from those in high body weight. © 2015 Taylor & Francis.

Osaki S.,Nara Medical University | Osaki M.,Tokyo Kyosai Hospital
Polymer Journal | Year: 2011

During their evolutionary history, some species of spiders have changed from a nocturnal to a diurnal lifestyle, and the important change in their environment was irradiation by sunlight. Orb webs of diurnal spiders may be markedly affected by exposure to ultraviolet (UV) irradiation, whereas those of nocturnal spiders may be unaffected. It is of great interest to consider the effects of UV rays on the mechanical properties of spider silks from the viewpoint of evolution. The webs of orb-weaving spiders must trap insect prey, which closely relates to the breaking energy of the spider silk constituting the orb webs. The effects of UV rays on the mechanical properties, particularly the mechanical breaking energy, of the silks of diurnal and nocturnal spiders were investigated. UV rays mechanically strengthened the draglines of diurnal Nephila clavata and two other kinds of diurnal spiders (Leucauge blanda and Argiope bruennichii), suggesting that the ability of the orb web to capture insects requires less maintenance. However, UV rays mechanically weakened the draglines of nocturnal Yaginumia sia and one other kind of nocturnal spider (Neosona nautica), suggesting a decrease in the ability of the orb web to capture insects. The results provide strong support that diurnal spiders are in a more evolved stage than nocturnal spiders, so they secrete silks with an evolved mechanical resistance against UV irradiation. This study suggests a means to search for biological materials with resistance to UV rays. © The Society of Polymer Science, Japan (SPSJ) All rights reserved.

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