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Introduction: Basal cell carcinoma (BCC) is a common skin cancer that rarely metastasizes but can deeply infiltrate local tissues. The small number of unresectable BCC cases makes it difficult to conduct clinical trials, resulting in delays in the development of effective drugs for BCC. Cancer gene panel testing has led to an increasing number of new treatment proposals for patients with solid tumors for whom no standard treatment is available., Case Presentation: We described a case of unresectable BRCA1 L63*-mutated BCC invading the parietal bone, which was successfully treated with cisplatin and fluorouracil., Conclusion: Our present case suggests that comprehensive mutation analysis by gene panel testing is important in advanced BCC because genes other than those involved in the hedgehog signaling pathway can be driver genes., Competing Interests: The authors have no conflicting interests to declare., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Introduction: Capicua transcriptional repressor (CIC)-DUX4 rearranged sarcoma is a subtype of CIC-rearranged sarcomas composed of undifferentiated Wilms' tumor 1 (WT1) + , CD99 + round cells with recurrent CIC gene rearrangement. The diagnosis of CIC-rearranged sarcoma remains challenging, and the prognosis of CIC-rearranged sarcomas is poor., Case Presentation: In this report, we described a case of CIC-DUX4 rearranged sarcoma presenting in the skin, expressing WT1 and CD99 in a dot-like pattern. In addition, the assessment of genomic alterations using genome panel testing was useful to confirm the accurate diagnosis., Conclusion: Our present case suggests that widespread use of genomic panel testing in the future may lead to early treatment and improve the prognosis of CIC-rearranged sarcomas., Competing Interests: The authors have no conflicting interests to declare., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Background/aims: Gastroesophageal reflux disease (GERD)-related disorders of systemic sclerosis (SSc) patients have not been adequately investigated., Methods: Sixty-six SSc patients (5 males and 61 females; 56.6 ± 14.6 years old) who underwent esophagogastroduodenoscopy were analyzed on the basis of 16 background factors. They were additionally compared with 116 matched non-SSc subjects controlling age, sex, and use of proton pump inhibitors (PPIs)., Results: The mean disease duration of 66 patients was 5.1 ± 8.1 years, and their breakdown was as follows: 53 (80.3%) with GERD, 38 (57.6%) with GERD-related symptoms, and 20 (30.3%) with reflux esophagitis (RE; LA-A: 10, LA-B: 5, LA-C: 4, LA-D: 1). Use of PPI (p = 0.0455), complication of interstitial lung disease (p = 0.0242), and history of cyclophosphamide therapy (p = 0.0184) denoted significant association with GERD-related symptoms. Older age (p = 0.0211) was significantly associated with RE. None of GERD-related disorders showed any difference between 37 diffuse cutaneous SSc and 29 limited cutaneous SSc patients. The matched analysis indicated that SSc patients had higher prevalence of GERD (p < 0.0001), GERD-related symptoms (p = 0.0034), and RE (p = 0.0002)., Conclusion: SSc patients tend to have worse GERD symptoms and severer RE. However, most SSc-associated factors did not show significant association with GERD-related disorders, indicating the difficulty in predicting GERD-related disorders among SSc patients., (© 2018 S. Karger AG, Basel.)

An epithelial cyst in an intrapancreatic accessory spleen (ECIAS) is rare. We herein report a case of a patient with ECIAS who underwent laparoscopic surgery. A 57-year-old woman was referred to our hospital because of a pancreatic tail tumor. She was asymptomatic, and a physical examination revealed no remarkable abnormalities. The levels of the tumor marker carbohydrate antigen 19-9 (CA19-9) and s-pancreas-1 antigen (SPan-1) were elevated. Ultrasonography showed a well-defined homogeneous cystic tumor. Computed tomography showed a well-demarcated cystic tumor in the pancreatic tail. Magnetic resonance imaging showed that the cystic tumor exhibited low intensity on T1-weighted images and high intensity on T2-weighted images. The cystic tumor was diagnosed as mucinous cystic neoplasm preoperatively. The patient underwent laparoscopic spleen-preserving distal pancreatectomy. A histopathological examination revealed the cyst wall to be lined by stratified squamous epithelium within splenic parenchyma, and the ultimate diagnosis was ECIAS. The postoperative course was uneventful, and the patient was discharged on postoperative day 12. ECIAS is very difficult to diagnose preoperatively. Laparoscopic surgery is a safe and minimally invasive procedure for patients with difficult-to-diagnose pancreatic tail tumor suspected of having low-grade malignancy.

Background: Pre-dialysis early referral is associated with improved survival in patients on dialysis. Here, we examined the association between pre-dialysis early referral and post-dialysis Mental Health (MH) in hemodialysis patients., Methods: We examined data from the Dialysis Outcomes and Practice Patterns Study (DOPPS), a prospective and observational study of hemodialysis patients, by performing a cross-sectional and longitudinal analysis of DOPPS data from Japan. The outcome measure was analyzed from the MH subscale of the Medical Outcomes Study Short Form-36 Item Health Survey. Predictors of mean MH were identified using analysis of covariance. The variables evaluated in the multivariate models included age, sex, duration of dialysis and diabetes., Results: A total of 552 patients under hemodialysis participated in the study, with a late referral prevalence of 34.2% (189/552). The estimated mean MH score was 60.7 (95% confidence interval (CI) 57.5-63.8) and 65.6 (95% CI 63.2-68.1) in late and early referrals, respectively. A statistically significant difference in mean MH score of 4.9 was observed between late and early referral groups (p = 0.01). The mean MH score for late referral was significantly lower than that for early referral in the 6-12 and 12-18 month groups., Conclusions: Pre-dialysis early referral is a modifiable and important factor and is associated with improved MH of post-dialysis patients., (Copyright 2009 S. Karger AG, Basel.)

Background/aims: Given the clear benefits of mortality reduction observed for most beta-blockers in clinical trials, they are relatively underused in hemodialysis patients. Since the outcomes associated with the use of beta-blockers are not fully known, we investigated their effect on mortality among a cohort of hemodialysis patients., Methods: Data were analyzed from the Dialysis Outcomes and Practice Patterns Study phase II for 2,286 randomly selected patients on hemodialysis in Japan. Treatment with beta-blockers was the major predictor variable. The main outcome measure was all-cause mortality. Cox regression analysis was used to assess an association between treatment with beta-blockers and the risk of death., Results: 247 patients (11.9%) were administered beta-blockers and 1,828 patients (88.1%) were not. Whereas patients treated with beta-blockers had a higher prevalence of hypertension and coronary heart disease, Kaplan-Meier analysis revealed that all-cause mortality rates were significantly (p < 0.007) decreased in patients treated with beta-blockers compared to those without. In multivariable, fully adjusted models, treatment with beta-blockers was also independently associated with reduced all-cause mortality (hazard ratio = 0.48; p = 0.02)., Conclusion: This study indicated a possible association between the use of beta-blockers and reduced risk of mortality in hemodialysis patients. These results should be confirmed in further randomized controlled trials., (Copyright 2009 S. Karger AG, Basel.)

Background: Considerable controversy exists over the impact of the biocompatibility and flux characteristics of dialyzer membranes on anemia in chronic hemodialysis patients., Methods: A subset of 1,207 subjects from the Japanese arm of DOPPS phase II was analyzed., Results: Patient characteristics included mean age 59 years, male sex 60%, BMI 20.6, time on dialysis therapy 7.8 years, and diabetes rate 27%. Dialysis parameters were Kt/V 1.33, and normalized protein catabolic rate 1.05 g/kg/day. Initial hemoglobin level was 10.1 g/dl. 79% were treated by intravenous erythropoietin with mean weekly doses of 4,500 IU. Hemoglobin levels and erythropoietin doses during 2-year study period were not affected by dialysis membrane biocompatibility (unmodified cellulose or biocompatible) or flux (standard or high performance). The 2-year survival rate was 90.9% and was influenced by older age, presence of cardiovascular diseases and amyloidosis, lower levels of BMI and serum albumin, but not by other variables, including dialysis membranes. Use of biocompatible membranes was associated with a lower all-cause mortality (8.3 vs. 13.0% for bioincompatible, p = 0.037), but this difference was not significant in multivariate analyses (hazard ratio 0.70, p = 0.17 by Cox multivariate analysis)., Conclusion: The biocompatibility and permeability of dialyzer membranes had no effect on anemia, erythropoietin dosage or all-cause mortality in Japanese chronic hemodialysis patients treated by non-reuse dialysis., (Copyright 2008 S. Karger AG, Basel.)

It has been suggested that reactivation of human herpesvirus 6 (HHV-6) infection may be involved in the pathogenesis of drug-induced hypersensitivity syndrome. We report a 45-year-old Japanese man who developed a generalized papuloerythematous rash, fever, hepatitis, lymphadenopathy and lymphocytosis with an increased number of atypical lymphocytes. He was diagnosed with DIHS due to mexiletine hydrochloride based on laboratory data, results of a patch test and the clinical course of his complaint, and was treated with systemic steroids. In order to determine whether HHV-6 or -7 was associated with the patient's disease, serological assays and PCR were carried out. Significant increases in antibody titers against HHV-6 and -7 were observed from day 12 to 24. From PCR analysis, none of the peripheral blood mononuclear cells or skin tissue samples contained HHV-6 DNA. All samples, however, were found to contain HHV-7 DNA. Reactivation of HHV-7 could be responsible for drug-induced hypersensitivity syndrome., (Copyright (c) 2006 S. Karger AG, Basel.)

Background/aims: Chronic hypokalemia increases NHE3 activity in OKP cells. The aim of the present study was to determine whether an autocrine mechanism is involved in this activation., Methods: After incubation of OKP cells in normal-K(+) and low-K(+) media for 24 h, the potassium concentration in the low-K(+) media was adjusted to a normal level. These conditioned media were then used as the normal-K(+) and low-K(+) supernatants. Other OKP cells were incubated in these normal-K(+) and low-K(+) supernatants and the mechanism of Na(+)/H(+) antiporter activation was examined., Results: The EIPA-resistant Na(+)/H(+) antiporter activity of OKP cells increased after 4 h incubation in the low-K(+) supernatant, and the amount of NHE3 protein increased at 24 h. Since both BQ788 and saralasin blocked this antiporter activation, the supernatant concentration of endothelin I (ET-I) and angiotensin II (Ang-II) were measured. The ET-I concentration was reduced, but the Ang-II concentration remained unchanged. There was a significant association between a reduction in the ET-I concentration and an increase in Na(+)/H(+) antiporter activity, but only when Ang-II was present in the supernatant., Conclusion: An autocrine mechanism is involved in the activation of NHE3 in OKP cells. Both ET-I and Ang-II play a role in this activation., (Copyright 2004 S. Karger AG, Basel)

Background/aim: Gene transfer into the kidney has great potential as a novel therapeutic approach. However, an efficient method of gene transfer into the kidney has not been established. We explored the transduction efficiency of renal cells in vitro and in vivo using adeno-associated virus (AAV) serotype 1-5 vectors encoding the beta-galactosidase gene., Methods: In the in vitro study, rat kidney epithelial cell line NRK52E cells were transfected with AAV serotype derived vectors. In the in vivo study, AAV serotype derived vectors were selectively injected into the kidney using a catheter-based gene delivery system in rats and mice mimicking the clinical procedure. The efficiency of gene expression was histologically evaluated on the basis of the beta-galactosidase expression., Results: AAV serotype 1, 2, and 5 vectors transduced in rat kidney epithelial cell line NRK52E cells in vitro, whereas AAV serotype 3 or 4 vectors showed no transduction. In addition, the kidney-specific injection of AAV serotype 2 vectors successfully transduced in tubular epithelial cells, but not in glomerular, blood vessel, or interstitial cells in vivo, whereas the rest of the serotypes showed no transduction., Conclusion: Since kidney-specific gene delivery via the renal artery by catheterization is highly feasible in humans, these findings provide useful information for promising strategies in renal gene therapy., (Copyright 2004 S. Karger AG, Basel)

It has been reported that calcium deposition and calcium content in cultured human aortic smooth muscle cells (SMC) increased when the cells are incubated in a medium with a high phosphate concentration (2 mM). To determine the cellular components or soluble factors contributing to the deposition, we cultured commercially available SMC, fibroblasts (Fb) and endothelial cells (Ed). These cells and their mixtures were incubated for 10 days in normal or high-phosphate media. Calcium crystals were stained by the von-Kossa staining and counted in the defined area. Calcium content was measured by a colorimetric assay. SMC were incubated in high-phosphate media (up to 2 mM) or beta-glycerophosphate (beta-GP) media, resulting in no obvious deposition of calcium crystals, irrespective of the coating of type I collagen on the dish. Next, various combinations of cells were cultured, and a significant number of depositions were observed only when Fb were included in the combination. The calcium content was significantly higher in cultures of SMC and Fb. The calcium deposition on single or mixture of the cells did not increase compared with control when cells were incubated in a high concentration of phosphate, cultured in the existence of beta-GP or uremic serum. We therefore conclude that Fb, rather than SMC or Ed, are essential for calcium deposition and calcium accumulation in culture. Phosphate concentration in the medium and uremic serum did not influence the deposition of calcium., (Copyright 2002 S. Karger AG, Basel)

Newly recognized strain of mice with hereditary polyuria (PUS mice) was characterized. Polyuria was inherited as a single autosomal-recessive trait. At 15 weeks, PUS mice excreted hypotonic (urine osmolality: PUS;270.8 +/- 15.5 vs. cont.; 3,228.6 +/- 163.6 mosm/kg) polyuria (urine volume: PUS; 25.0 +/- 1.5 vs. cont.; 1.1 +/- 0.1 ml/day). In PUS mice, plasma osmolality was slightly elevated as well as urinary excretion of vasopressin (AVP). Although PUS mice could concentrate urine after 24 h water deprivation, urine osmolality remained low. Blunted response to continuous infusion of dDAVP, a synthetic V2 agonist, was also observed. These in vivo studies indicated renal resistance to AVP contributed to the polyuria in this strain of mice. Microanalysis of isolated tubular segments revealed that AVP-induced cAMP accumulation in cortical collecting ducts (CCD) of PUS mice was significantly lower (60%) with or without a phosphodiesterase inhibitor, IBMX. Vasopressin induced similar cAMP accumulation in medullary ascending limbs of Henle (MAL), and medullary collecting ducts (MCD) between PUS and control mice. In CCDs, PUS mice had low basal adenylate cyclase (AdC) activity and responded less to AVP and forskolin stimulation than control mice. No difference in cyclic AMP phosphodiesterase activity was detected between control and PUS mice. These results indicate that impaired cAMP accumulation due to low AdC activity may be related to the impaired renal concentrating ability observed in this new strain of mice., (Copyright 2002 S. Karger AG, Basel)

Background/aims: A recent observation that antiplatelet-aggregation drugs, including ticlopidine hydrochloride, may prevent erythropoietin (EPO)-induced rise in blood pressure in hemodialysis (HD) patients remains a subject of particular interest. The aim of the present study was to determine the effect of ticlopidine hydrochloride on EPO-induced rise in blood pressure of HD patients with special reference to blood levels of vasoactive substances., Methods: HD patients who showed hypertension or aggravation of preceding hypertension with EPO treatment were selected for this study. Ticlopidine hydrochloride was administered at a dose of 200 mg daily for 4 weeks. Blood pressure and serum levels of nitric oxide (NO), atrial natriuretic peptide (ANP) and endothelin (ET) were determined before and after drug administration. Patients were divided into two groups, one of which showed a drop in mean blood pressure (MBP) of >10 mm Hg (group I) and one which did not (group II), and a comparison was made between them with respect to the blood parameters., Results: Five of 15 patients showed a drop of MBP of >10 mm Hg (group I), and 10 patients did not show any change in MBP (group II). In group I, there was a significant increase in blood NO levels compared to the concentrations before ticlopidine administration, while there was no change in group II. With respect to ANP and ET, there was no significant change in either of the groups., Conclusion: The findings suggest that the preventive effect of ticlopidine hydrochloride on EPO-induced rise in blood pressure may partly be related to the enhancement of NO production in patients on maintenance HD., (Copyright 2002 S. Karger AG, Basel)

Background: We previously found that the Na(+)/H(+) exchanger 3 (NHE3) is localized in the apical membrane of the rat renal proximal tubule and thick ascending limb of Henle. In the present study, we examined the direct effect of glucagon on the opossum kidney P (OKP) cell Na(+)/H(+) antiporter, encoded by NHE3., Methods: Na(+)/H(+) antiporter activity was measured as the rate of cell pH recovery from an acid load using 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. Northern blot and Western blot analyses were performed using OKP NHE3 cDNA and anti-OKP-NHE3 antibodies., Results: Glucagon (1 ng/ml) acutely (1 h) inhibited, but chronically (24 h) activated NHE3 activity in OKP cells. These effects were blocked by either KT5720 or RpcAMP [protein kinase A (PKA) inhibitors], and mimicked by 10(-4) M dibutyryl-cAMP. Both NHE3 mRNA and protein abundance increased with the 24-hour incubation in glucagon or dibutyryl-cAMP. Cycloheximide did not prevent a significant increase in NHE3 activity at 24 h. We therefore examined NHE3 protein abundance in the surface membrane by the biotinylation method. cAMP or glucagon significantly increased NHE3 protein abundance in the surface membrane when incubated with cycloheximide for 24 h., Conclusions: Glucagon acutely inhibits but chronically activates NHE3 activity in OKP cells via a PKA-dependent pathway. Both protein-synthesis-dependent and -independent mechanisms play important roles in the chronic activation of NHE3., (Copyright 2002 S. Karger AG, Basel)

Background: Hemodialysis patients who had been treated with anti-platelet aggregation drugs, including ticlopidine, sometimes developed hypotension. The mechanism by which ticlopidine lowers the blood pressure in hemodialysis patients is unclear. To elucidate the mechanism of the action of this drug, we investigated cytokine-stimulated nitric oxide (NO) metabolism by ticlopidine in cultured rat vascular smooth muscle cells (VSMC)., Methods: Nitrite, a stable metabolite of NO, and intracellular cAMP and cGMP contents were assayed by the Griess method and enzyme immunoassay, respectively. iNOS mRNA and protein expressions were analyzed by Northern blotting and Western blotting., Results: Ticlopidine enhanced interleukin-1beta (IL-1beta)-induced nitrite production in a dose- and time-dependent manner. The mRNA and protein expressions of inducible NO synthase were upregulated by ticlopidine in a dose- and time-dependent manner. IL-1beta alone stimulated both intracellular cAMP and cGMP contents, and the addition of ticlopidine further enhanced their contents. KT 5720, a selective inhibitor of protein kinase A, but not KT 5823, a selective inhibitor of protein kinase G, abolished the enhancement of IL-1beta-induced nitrite production by ticlopidine. In addition, a phosphodiesterase inhibitor, isobutylmethylxanthine, enhanced IL-1beta and ticlopidine induced nitrite production., Conclusion: We concluded that ticlopidine enhanced the IL-1beta-induced NO production via cAMP and subsequent activation of protein kinase A in cultured rat VSMC., (Copyright 2002 S. Karger AG, Basel)

Background/aim: Recently, we observed a progressive decline in the plasma ionized calcium (iCa) concentration after ingestion of Na-free beverage. Although both plasma pH and Na significantly correlated with iCa, the correlation of the latter was stronger than that of the former. Therefore, we explored the effect of Na on plasma iCa., Methods: Pooled human plasma was diluted with normal saline, 5% glucose, 0.9% KCl, or distilled water to examine the effect of plasma dilution on iCa. Also, to evaluate the effects of an isovolemic increase in ion concentration and osmolarity on plasma iCa, NaCl, KCl, and D-glucose were added to plasma. Electrolytes (Na(+), K(+), Cl(-), iCa, HCO(-)(3)), pH, and osmolarity were measured by using ion-selective electrodes., Results: In the plasma dilution study, although all solutions significantly decreased the iCa concentration, the decrease in iCa concentration in the normal saline treated solution was significantly lower than in others. When the plasma osmolarity was isovolemically increased, the iCa concentration significantly increased in parallel with the increase in osmolarity in the NaCl group (r = 0.604, p < 0.01, n = 50). In contrast, no significant change in the iCa concentration was seen in the other solutions. NaCl did not increase, but rather decreased the iCa concentration when added to a protein-free solution., Conclusion: The present study demonstrated that Na specifically affects plasma iCa independently of pH, presumably via modulating Ca binding to plasma proteins., (Copyright 2001 S. Karger AG, Basel)

Familial lecithin:cholesterol acyltransferase (LCAT) deficiency is a rare genetic disorder of the lipid metabolism caused by the absence of LCAT activity in plasma. It is not generally accompanied by atherosclerosis in spite of low high-density lipoprotein cholesterol levels nor by diabetes mellitus. However, reports of long-term follow-up or autopsy findings are rare, and the true incidence of atherosclerosis in LCAT deficiency is not clear. We report on the long-term observation of a patient with familial LCAT deficiency who developed renal failure, diabetes mellitus, and marked atherosclerosis. The patient died of sepsis from foot ulcers 7 years after starting hemodialysis and 13 years after the diagnosis. Marked atherosclerosis characterized by medial calcification in small arteries was observed at autopsy. The genesis of the atherosclerosis seemed to be on the basis of a combination of factors., (Copyright 2001 S. Karger AG, Basel)

A 24-year-old Japanese woman with IgA nephropathy exhibited a decreased serum aldosterone level with normal plasma renin activity after toxemia of pregnancy. Our studies revealed selective hypoaldosteronism with normal adrenoglucocorticoid functions. Levels of serum corticosterone and deoxycorticosterone were normal. Resting plasma renin activity was normal, and plasma levels of total and inactive renin were increased. Rapid ACTH administration failed to stimulate any secretion of aldosterone, whereas it adequately increased serum cortisol, deoxycorticosterone, and corticosterone concentrations. Responses of both plasma renin activity and serum aldosterone level to the furosemide-posture challenge were blunted. Angiotensin II also failed to stimulate any secretion of aldosterone despite a progressive rise in blood pressure and an appropriate increase in serum corticosterone. These results suggest that combined defects of the conversion from inactive renin to active renin and aldosterone biosynthesis are the causes of selective hypoaldosteronism in our patient., (Copyright 2001 S. Karger AG, Basel)

Background: It has been reported that human recombinant erythropoietin (rHuEPO) modulates the sensitivity of the cardiovascular system to vasoconstrictors. We investigated whether rHuEPO has modulative effects on the endothelin-1 (ET-1)-induced elevation of cytosolic free calcium concentration ([Ca2+]i) and mitogen-activated protein (MAP) kinase activation in vascular smooth muscle cells (VSMC)., Methods: [Ca2+]i was measured by fura-2/AM, and MAP kinase activation was analyzed by Western blotting., Results: Exposure of VSMC to rHuEPO prior to stimulation with ET-1 enhanced both basal and ET-1-induced elevation of [Ca2+]i in a dose-dependent manner in the presence of extracellular Ca2+. The synergistic effect was also retained in the absence of extracellular Ca2+ after exposure to rHuEPO. However, the effect was diminished in the presence of extracellular Ca2+ combined with the intracellular Ca2+ release inhibitor TMB-8, PKC inhibitor, or PKC depletion. Exposure to rHuEPO also had a synergistic effect on the activation of MAP kinase induced by ET-1; however, this effect was diminished in the presence of the Ca2+ chelator BAPTA-AM., Conclusion: The results suggest that rHuEPO has synergistic effects on ET-1-induced [Ca2+]i mobilization, particularly on intracellular Ca2+ release, and MAP kinase activation in VSMC., (Copyright 2001 S. Karger AG, Basel)

Thiazolidinedione derivatives, new insulin-sensitizing antidiabetic agents, are expected to have potential clinical use. Since these drugs cause edema in a variable proportion of patients, we examined whether troglitazone (Tro) has direct action on Na+ transport of rabbit proximal straight tubule perfused in vitro. For this purpose, we measured basolateral membrane voltage (V(B)) by conventional microelectrode techniques and intracellular pH (pH(i)) by microscopic fluorescence spectrophotometry with a pH-sensitive fluorescent dye, 2', 7'-bis-2-carboxyethyl-5-carboxyfluorescein. Tro at 50 microM in the bath significantly depolarized both transepithelial voltage and V(B). To examine whether the basolateral rheogenic Na+/HCO3- cotransport activity is affected by Tro, we observed V(B) deflection upon abrupt 10-fold decrease in bath HCO3- in the absence and presence of Tro. The apparent transference number of HCO3- (tHCO3), as calculated from the V(B) deflection, was significantly greater in the presence of Tro (50 microM) than that seen in its absence. Tro caused cell acidification and increased the intracellular acidification rates (dpH(i)/dt) upon abrupt 10-fold decreases in bath HCO3- and Na+ concentrations. The stimulatory effects of Tro on tHCO3 and dpH(i)/dt were dose dependent between 5 and 50 miccroM, but they were unaffected at 0.5 microM. From these results, we conclude that Tro acts on the proximal straight tubule and stimulates the basolateral rheogenic Na+/HCO3- cotransport activity. The stimulatory action of Tro may partly account for edema formation., (Copyright 2001 S. Karger AG, Basel)

Epidermal growth factor (EGF) inhibits amiloride-sensitive Na(+) conductance in the apical membrane of the isolated rabbit cortical collecting duct. However, there is no information on the relationship between electrolyte transport and tyrosine kinase. We examined the effect of EGF on transport of potassium and chloride as well as sodium and the roles of tyrosine kinases in the rabbit cortical collecting duct using in vitro isolated tubular microperfusion. Basolateral EGF depolarized the transepithelial voltage in a dose-dependent manner within a concentration range of 10(-10) in 10(-8) M. Basolateral ouabain and luminal amiloride completely abolished EGF-induced depolarization. However, luminal BaCl(2) did not abolish its depolarization. To confirm the mechanism, sodium, potassium, and chloride fluxes were measured in the presence of 10(-10) M EGF. EGF significantly decreased the lumen-to-bath isotope flux of sodium and chloride from 93.6+/-12.5 to 61.1+/-9.6 pmol/mm/min (n = 5, p<0.05) and from 86.6+/-10.0 to 54. 8+/-9.7 pmol/mm/min (n = 10, p<0.01), respectively. EGF also decreased net potassium secretion from -27.7+/-5.9 to -7.8+/-1.5 pmol/mm/min (n = 6, p<0.01). To examine whether EGF-induced depolarization is mediated by tyrosine kinase, tyrosine kinase inhibitors were applied from the basolateral side. Pretreatment with 1 microg/ml herbimycin A for 120 min completely abolished EGF-induced depolarization (90.9+/-5.4%, n = 4; NS). Herbimycin A itself also did not change the lumen-to-bath isotope flux of sodium and completely abolished the inhibition of Na(+) absorption on EGF action (control 65.4+/-6.8, herbimycin A 61.8+/-6.3, EGF with herbimycin A 60.0+/-4.4 pmol/min/mm, n = 5; NS). In conclusion, EGF depolarizes transepithelial voltage by inhibiting sodium transport primarily and potassium and chloride transport secondarily. These effects were blocked by nonspecific tyrosine kinase inhibitors.

Objective: To elucidate the effect of atrial natriuretic peptide (ANP) on cytokine-induced nitric oxide (NO) production, we examined whether ANP affects IL-1 beta-stimulated NO production and inducible NO synthase (iNOS) mRNA expression in cultured rat vascular smooth muscle cells (VSMC)., Methods: VSMC were incubated with test agents for 24 h. The nitrite concentration of the culture medium, a stable-end product of NO, was measured by the column reduction method. NOS mRNA expression was analyzed by Northern blotting. The intracellular cAMP content was measured by enzyme immunoassay. cAMP-dependent kinase (PKA) activity was determined by a PKA assay system., Results: IL-1 beta stimulated nitrite production in VSMC. ANP (10 nM to 1 mM) enhanced the nitrite production and iNOS mRNA expression in the presence of IL-1 beta. Both 8-bromo-guanosine 3',5'-cyclic monophosphate (8-br-cGMP) and dibutylyl adenosine 3',5'-cyclic monophate enhanced IL-1 beta-induced nitrite production. The effects of these two nucleotide donors on the nitrite production were not additive, suggesting a common pathway. KT 5720, an inhibitor of PKA, abolished the enhancement of nitrite production by ANP and 8-br-cGMP, while KT 5823, an inhibitor of cGMP-dependent protein kinase, did not inhibit the enhancement. In the in vitro assay 8-br-cGMP increased PKA activity., Conclusions: ANP and cGMP enhanced IL-1 beta-induced NO production in VSMC. PKA rather than PKG may be involved in the enhancement.

Opportunistic infections caused by gram-negative rods (GNR), conventionally regarded as organisms with low or no pathogenicity, and intractable infections caused by various resistant organisms pose a great problem now. In view of this, we determined the bactericidal effects of 5 commonly used disinfectants using as the test strains Xanthomonas maltophilia and Serratia marcescens, chosen among other GNR since they often cause nosocomial infections. Regarding the bactericidal activities against X. maltophilia and S. marcescens, both sensitive strains and resistant strains were killed within 20 s of exposure to povidone-iodine and sodium hypochlorite. With chlorhexidine, 1 strain each of both species was not killed within 10 min of exposure at a concentration of 0.2%. Both sensitive strains and resistant strains of X. maltophilia were killed within 20 s of exposure to benzalkonium at 0.02%, while a concentration of 0.1% was required for benzalkonium to kill S. marcescens within 20 s. With Tego-51, both sensitive strains and resistant strains of X. maltophilia were killed within 20 s at 0.02%, while 1 strain of S. marcescens was not killed within 20 s at a concentration of 0.1%. In the use of disinfectants, comparative bactericidal effects of various disinfectants against clinical isolates should be taken into consideration.

To evaluate the roles of cAMP degradation on hormonal actions in the kidney, we examined the segmental distribution and activities of cAMP-phosphodiesterase (PDE), a key enzyme for cAMP hydrolysis, in dissected segments of the rat nephron and characterized the isozyme compositions with subtype-specific inhibitors. Summary of the nephron distribution of PDE activities showed that cAMP-PDE activities were detected in all nephron segments and the distal convoluted tubules (DCTs) had the highest activity. Both in proximal convoluted tubules (PCTs) and medullary collecting ducts (MCDs), more than 80% of the total cAMP-PDE activities were inhibited by a nonspecific PDE inhibitor, 3-isobutyl-1-methylxanthine (IBMX). In PCTs, rolipram (type-IV PDE inhibitor) was an equally potent inhibitor of IBMX, while 8-methoxymethyl-IBMX (MM-IBMX, type-I PDE inhibitor) and cilostamide (type-III PDE inhibitor) inhibited cAMP-PDE by 35 and 57%, respectively. In MCDs, inhibition by rolipram (40%) was less than that by MM-IBMX (70%) or cilostamide (66%). Rolipram potentiated the parathyroid hormone (PTH)-induced cAMP content in PCTs most effectively. Rolipram and MM-IBMX increased the vasopressin (AVP)-stimulated cAMP content equally in MCDs. Cilostamide had no effect on the cAMP content stimulated by PTH or AVP in PCTs and MCDs. These results indicate that PDE activities were unevenly distributed along the rat nephron and cAMP-PDE was composed of at least three isoforms, namely type I, III and IV in PCTs and MCDs. Among these, type-IV PDE was responsible for hydrolysis of cAMP in PCTs, and type-I and IV PDE were responsible for that in MCDs.

Long-term exposure to trichloroethylene can cause kidney cancer in experimental animals and humans. In addition, dichloroacetylene (a breakdown product of trichloroethylene) is nephrotoxic and neurotoxic. Both trichloroethylene and dichloroacetylene are metabolized in part to the corresponding cysteine S-conjugate (i.e. S-(1,2-dichlorovinyl)-L-cysteine) which is toxic. Cysteine S-conjugate beta-lyases convert S-(1,2,dichlorovinyl)-L-cysteine to pyruvate, ammonia and a reactive fragment that adds to macromolecules, depletes cellular thiols and causes lipid peroxidation. We now show that S-(1,2-dichlorovinyl)-L-cysteine and another nephrotoxic cysteine S-conjugate, S-(1,1,2,2-tetrafluoroethyl)-L-cysteine, inactive purified cytosolic aspartate aminotransferase and purified alanine aminotransferase. These cysteine S-conjugates also inactive aspartate aminotransferase in cytosolic and mitochondrial fractions of rat brain and kidney. The present results suggest that some halogenated xenobiotics may be toxic in part through their conversion to the corresponding cysteine S-conjugate which inactivates key pyridoxal 5'-phosphate-containing enzyme.

During hemodialysis therapy, a large amount of water is removed from the patient's blood in a short time; however, blood pressure remains stable in most patients. As water is removed, the circulating serum proteins become more concentrated, resulting in a marked increase in the driving force which pulls water from the extravascular space into the blood vessels, by a process called plasma refilling. However, since a method for studying plasma refilling has not previously been proposed, it is not known what determines the plasma refilling capacity of hemodialysis patients. To evaluate the plasma refilling capacity of patients, we propose here a method for calculating an index of plasma refilling capacity, which we have called the plasma-refilling coefficient (Kr). In 14 patients receiving maintenance hemodialysis therapy, total serum protein was measured before hemodialysis, and hematocrits were measured hourly during hemodialysis. From the changes in the hematocrits, we estimated the changes in the circulating plasma volume and in the intracapillary oncotic pressure at each time point. The water removal rate was also measured hourly. From these values, we calculated Kr. An averaged volume of 2,692 +/- 219 ml of water was removed from each patient resulting in a decrease in the estimated circulating blood volume, while the hematocrit and the estimated intracapillary oncotic pressure increased gradually. Kr calculated after 1 h of hemodialysis varied widely between patients, 140.3-1,744.2 ml/mm Hg/h, and decreased gradually as water removal continued. The average Kr of 14 patients was 698.9 +/- 15.2 ml/mm Hg/h at the beginning of water removal, and it decreased to 405.3 +/- 75.4, 203.9 +/- 39.5, 130.2 +/- 20.5 and 93.9 +/- 14.3 each hour thereafter. The index of plasma refilling proposed in this paper is useful for examining capillary water permeability and the degree of plasma refilling in hemodialysis patients.

Hypotension is frequently encountered during hemodialysis (HD). One of the main factors of the HD-induced hypotension is acute reduction of circulating plasma volume by water removal, which is induced by the poor plasma refilling from the extravascular space into vessels. The determinants of plasma refilling, however, have not been clearly identified. Recently, we devised a mathematical model of water transport in HD patients, which can estimate the plasma-refilling coefficient (Kr) during HD. In the present study, we evaluated the factors determining plasma refilling by using this model. In 13 patients undergoing regular HD, the changes of Kr during HD were calculated from the model. Levels of ANP, cGMP, cAMP, endothelin, angiotensin II and vasopressin were measured before and after HD. Kr fell from 750.4 +/- 558.0 to 112.8 +/- 81.9 ml/mm Hg/h during HD. The rate of water removal during HD showed no significant correlation with the changes of Kr. Among the hormones and nucleotides measured here, plasma ANP level and cGMP were significantly correlated with Kr (r = 0.78, p < 001 and r = 0.62, p < 0.01, respectively). Our findings suggest that severe reduction in the level of serum ANP during HD, which is induced by water removal, plays some role in HD-induced hypotension through the attenuation of plasma refilling in HD patients.

The excimer-to-monomer (E/M) fluorescence ration of pyrene (p) and its derivatives has been found to correlate with membrane fluidity. We explored the possible use of this method in living renal epithelial cells. In Modin-Darby canine kidney cells, successful fluorescent labeling was obtained with p-cholesterol, p-trimethylammonium (TMA), p-sulfonamidethyl-TMA, p-butyrate, p-propanoate or p-dodecanoate. Among them, the labeling with p-cholesterol was most stable. The whole cell cholesterol content did not significantly increase after loading p-cholesterol and the probe incorporated was not degraded. The E/M ratio changed reproducibly and significantly by temperature change, a standard method to alter membrane fluidity. Thus, the E/M ratio of p-cholesterol fluorescence is suggested to be a potential parameter of membrane fluidity in living renal epithelial cells and might be useful in investigating the relationship between the physical state of the membrane and epithelial function.

Swelling-activated K flux was investigated in erythrocytes from patients on regular hemodialysis. K influx, measured by 86Rb uptake, was increased in hemodialysis patients from 25.5 +/- 0.6 to 47.3 +/- 3.4 nmol/10(9) cells/h (n = 4, p < 0.01), when the medium osmolarity of Hepes buffer was decreased by 100 mosm/kg H2O. In normal subjects, K influx was also stimulated from 28.1 +/- 1.2 to 37.8 +/- 2.1 nmol/10(9) cells/h (n = 4, p < 0.01). The swelling-activated increment of K influx was comparatively higher in hemodialysis patients (85.5 vs. 34.5% in controls). Reduction of the medium osmolarity by 100 mosm/kg H2O also caused a larger increase of K efflux in hemodialysis patients than in control subjects (171.1 vs. 118.1%). K efflux was increased even in the presence of 10(-4) M ouabain (from 284 +/- 25 to 879 +/- 122 nmol/10(9) cells/h), although the increment of K efflux was completely abolished when Cl was replaced by gluconate (555 +/- 47 nmol/10(9) cells/h with Cl and 467 +/- 44 nmol/10(9) cells/h without Cl). These data suggest that in hemodialysis patients, swelling-activated K transport is enhanced via activation of the Cl-dependent ouabain-insensitive K transport pathway.

To further characterize the alpha- and beta-intercalated cells (alpha-IC, beta-IC) in the isolated and perfused connecting tubule (CNT), cortical collecting duct (CCD) and outer medullary collecting duct in the inner stripe (OMCDi) of rabbit kidneys, we studied the effects of various transport inhibitors on electrical parameters. They included inhibitors of Cl-/HCO3- exchanger (4-acetamino-4'-isothiocyanostilbene-2,2'-disulfonic acid, SITS), carbonic anhydrase (acetazolamide) and Na(+)-K(+)-ATPase (ouabain). Upon addition of 10(-3) M SITS to the bath, the basolateral membrane voltage (VB) of alpha-IC in the OMCDi and CCD was significantly hyperpolarized by 20.8 +/- 4.6 (n = 5) and 29.8 +/- 5.6 mV (n = 11), respectively. On the other hand, luminal addition of SITS had no effects on VB of alpha-IC in the OMCDi and CCD. Neither bath nor lumen SITS affected VB of beta-IC in the CCD and CNT. When 10(-4) M acetazolamide was added to the bath, VB of alpha-IC in the OMCDi and CCD was significantly hyperpolarized by 20.0 +/- 4.1 (n = 4) and 18.6 +/- 1.7 mV (n = 3), respectively. Similarly, 10(-4) M acetazolamide in the bath caused the basolateral membrane of beta-IC in the CCD and CNT to hyperpolarize significantly by 34.3 +/- 7.9 (n = 6) and 21.6 +/- 2.9 mV (n = 3), respectively. Luminal addition of acetazolamide had no effect on VB of alpha-IC in the CCD and OMCDi and beta-IC in the CCD and CNT.(ABSTRACT TRUNCATED AT 250 WORDS)

A 51-year-old Japanese woman with hypokalemia due to distal renal tubular acidosis associated with Sjögren's syndrome exhibited a decreased plasma aldosterone level despite elevated plasma renin activity. Our studies revealed selective hypoaldosteronism with normal adrenoglucocorticoid function. In the presence of a low level of serum potassium (3.6 mEq/l), plasma levels of deoxycorticosterone and corticosterone were normal, while plasma aldosterone was very low. The levels of these three mineralocorticoids showed only minor changes during infusion of angiotensin II. Furosemide administration under almost the same level of serum potassium (3.7 mEq/l) resulted in only a slight increase of plasma aldosterone. Since hypokalemia might possibly suppress the synthesis of aldosterone in the zona glomerulosa, angiotensin II was also infused under a normal level of potassium (4.3 mEq/l). However, angiotensin II also failed to stimulate any secretion of aldosterone, despite a progressive rise in blood pressure and sufficient suppression of plasma renin activity. On the other hand, rapid ACTH administration in the presence of 4.4 mEq/l of serum potassium increased both plasma aldosterone and cortisol. These results suggest that adrenal insensitivity to angiotensin II was the cause of the selective hypoaldosteronism in our patient, possibly due to a dysfunction of adrenal angiotensin II receptors, a disorder of postreceptors or both.

We attempted treatment with methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU), a novel nitrosourea derivative, in a 55-year-old man with advanced-stage primary myelofibrosis. MCNU was given intravenously at a dose of 50 mg once a month. Following MCNU treatment, his anemia and splenomegaly improved markedly. An increased dose of MCNU (100 mg, once a month) was even more effective for relieving the symptoms. Severe side effects resulting from this therapy, such as leukocytopenia or thrombocytopenia, were never observed. These observations indicate that MCNU treatment may be a beneficial management of advanced-stage primary myelofibrosis.