RESUMO
Gene therapies may be promising for the treatment of peritoneal fibrosis (PF) in subjects undergoing peritoneal dialysis (PD). However, a method of delivery of treatment genes to the peritoneum is lacking. We attempted to develop an in vivo small interfering RNA (siRNA) delivery system with liposome-based nanoparticles (NPs) to the peritoneum to inhibit PF. Transforming growth factor (TGF)-ß1-siRNAs encapsulated in NPs (TGF-ß1-siRNAs-NPs) dissolved in PD fluid were injected into the peritoneum of mice with PF three times a week for 2 weeks. TGF-ß1-siRNAs-NPs knocked down TGF-ß1 expression significantly in the peritoneum and inhibited peritoneal thickening with fibrous changes. TGF-ß1-siRNAs-NPs also inhibited the increase of expression of α-smooth muscle actin-positive myofibroblasts. These results suggest that the TGF-ß1-siRNA delivery system with NPs described here could be an effective therapeutic option for PF in subjects undergoing PD.
Assuntos
Nanopartículas/uso terapêutico , Fibrose Peritoneal/terapia , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/uso terapêutico , Fator de Crescimento Transformador beta1/metabolismo , Animais , Modelos Animais de Doenças , Masculino , Camundongos Endogâmicos C57BL , Miofibroblastos/metabolismoRESUMO
Varying degrees of metabolic abnormalities mediated by chronic inflammation are implicated in the chronic glomerular injuries associated with obesity. Interleukin (IL)-10, a pleiotropic cytokine, exerts anti-inflammatory effects in numerous biological settings. In the present study, we explored the biological benefits of adeno-associated virus (AAV) vector-mediated sustained IL-10 expression against the pathological renal characteristics observed in Zucker fatty rats (ZFRs). We injected an AAV vector, encoding rat IL-10 or enhanced green fluorescent protein (GFP) into male ZFRs at 5 weeks of age. Subsequently, the renal pathophysiological changes were analyzed. Persistent IL-10 expression significantly reduced the urinary protein excretion of ZFRs compared with GFP expression (47.1±11.6 mg per mg·creatinine versus 88.8±30.0 mg per mg·creatinine, P<0.01). The serum levels of IL-10 negatively correlated with the urinary protein in AAV-treated rats (r=-0.78, P<0.01). Renal hypertrophy, increased widths in the glomerular basement membrane, and the lack of uniformity and regularity of the foot process of the visceral glomerular epithelial cells of ZFRs were significantly blunted by IL-10 expression. IL-10 also abrogated the downregulation of glomerular nephrin observed in ZFRs treated with the GFP vector. Our findings provide insights into the potential benefit of the anti-inflammatory effects of IL-10 on the overall management of glomerulopathy induced by the metabolic disorders associated with obesity.
Assuntos
Interleucina-10/genética , Proteinúria/terapia , Animais , Dependovirus/genética , Vetores Genéticos , Interleucina-10/sangue , Rim/patologia , Glomérulos Renais/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Obesidade/complicações , Obesidade/genética , Proteinúria/genética , Proteinúria/metabolismo , Proteinúria/patologia , Ratos , Ratos ZuckerRESUMO
Efficient injection of spin-polarized current into a semiconductor is a basic prerequisite for building semiconductor-based spintronic devices. Here, we use inelastic electron tunneling spectroscopy to show that the efficiency of spin-filter-type spin injectors is limited by spin scattering of the tunneling electrons. By matching the Fermi-surface shapes of the current injection source and target electrode material, spin injection efficiency can be significantly increased in epitaxial ferromagnetic insulator tunnel junctions. Our results demonstrate that not only structural but also Fermi-surface matching is important to suppress scattering processes in spintronic devices.
RESUMO
The nucleus 49Sc, having a single f(7/2) proton outside doubly magic 48Ca (Z=20, N=28), is one of the very few isotopes which makes possible testing of the fundamental theory of nuclear magnetism. The magnetic moment has been measured by online ß NMR of nuclei oriented at milli-Kelvin temperatures to be (+)5.616(25) µ(N). The result is discussed in terms of a detailed theory of the structure of the magnetic moment operator, showing excellent agreement with calculated departure from the f(7/2) Schmidt limit extreme single-particle value. The measurement completes the sequence of moments of Sc isotopes with even numbers of f(7/2) neutrons: the first such isotopic chain between two major shells for which a full set of moment measurements exists. The result further completes the isotonic sequence of ground-state moments of nuclei with an odd number of f(7/2) protons coupled to a closed subshell of f(7/2) neutrons. Comparison with a recent shell-model calculation of the latter sequence is made.
RESUMO
BACKGROUND: Nuclear factor (NF)-κB is a transcription factor that regulates cytokine and chemokine production in various inflammatory diseases, including bronchial asthma. IκB kinase (IKK) ß is important for NF-κB activation in inflammatory conditions, and is possibly related to airway remodelling. Thus, inhibition of the IKKß-NF-κB pathway may be an ideal strategy for the management of airway remodelling. OBJECTIVE: We examined the effects of a newly synthesized IKKß inhibitor, IMD-0354, in a chronic allergen exposure model of bronchial asthma in mice. METHODS: A chronic mouse model was generated by challenge with house dust mite antigen (Dermatophagoides pteronyssinus). IMD-0354 was administrated intraperitoneally in therapeutic groups. Lung histopathology, hyperresponsiveness and the concentrations of mediators and molecules in supernatants of lung homogenates were determined. RESULTS: NF-κB activation was inhibited by prolonged periods of IMD-0354 administration. IMD-0354 reduced the numbers of bronchial eosinophils. IMD-0354 also inhibited the pathological features of airway remodelling, including goblet cell hyperplasia, subepithelial fibrosis, collagen deposition and smooth muscle hypertrophy. Inhibition of these structural changes by IMD-0354 was the result of the suppressing the production and activation of remodelling-related mediators, such as TGF-ß, via inhibition of IKKß. IMD-0354 inhibited IL-13 and IL-1ß production, and it restored the production of IFN-γ. It also ameliorated airway hyperresponsiveness. CONCLUSION: IKKß plays crucial roles in airway inflammation and remodelling in a chronic mouse model of asthma. A specific IKKß inhibitor, IMD-0354, may be therapeutically beneficial for treating airway inflammation and remodelling in chronic asthma.
Assuntos
Remodelação das Vias Aéreas/efeitos dos fármacos , Antígenos de Dermatophagoides/imunologia , Asma/tratamento farmacológico , Asma/patologia , Benzamidas/farmacologia , Modelos Animais de Doenças , Quinase I-kappa B/antagonistas & inibidores , Remodelação das Vias Aéreas/imunologia , Animais , Asma/enzimologia , Asma/fisiopatologia , Benzamidas/química , Benzamidas/uso terapêutico , Doença Crônica , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Estrutura MolecularRESUMO
We report 2 cases with a good recovery from acute kidney injury (AKI) due to exercise-induced AKI associated with renal hypouricemia. Case 1 involves a 20-yearold man who had a similar episode 1 year earlier. He complained of nausea, vomiting and loin pain after playing football. On admission, his serum creatinine was 3.27 mg/dl and he was treated with intravenous fluid infusion (2 l/d). His renal function deteriorated and creatinine rose to 9.82 mg/dl. A renal hemodynamic evaluation using duplex Doppler ultrasound showed a high arterial resistance index (RI). After we changed his treatment to intravenous continuous infusion of 2 µg/kg/min dopamine, RI decreased sequentially and creatinine decreased without hemodialysis. A renal biopsy performed 7 days after dopamine infusion showed no changes in glomeruli and tubules, suggesting the absence of acute tubular necrosis, and no uric acid crystals or myoglobin casts in tubules. Case 2 involves a 42-year-old man who complained of loin pain after riding a motorcycle. On admission, his creatinine and creatine phosphokinase (CPK) were 3.93 mg/dl and 59 mU/ml, respectively. His RI was also high and he was treated immediately with an intravenous continuous infusion of 2 µg/kg/min dopamine. RI and creatinine decreased sequentially. Both cases suggest the effectiveness of dopamine infusion for AKI due to renal hypouricemia in which the RI of the renal arteries is high.
Assuntos
Injúria Renal Aguda/tratamento farmacológico , Dopaminérgicos/uso terapêutico , Dopamina/uso terapêutico , Erros Inatos do Transporte Tubular Renal/tratamento farmacológico , Cálculos Urinários/tratamento farmacológico , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/patologia , Adulto , Exercício Físico , Humanos , Masculino , Néfrons/patologia , Artéria Renal/fisiologia , Erros Inatos do Transporte Tubular Renal/complicações , Resultado do Tratamento , Cálculos Urinários/complicações , Resistência Vascular , Adulto JovemRESUMO
We describe here the interesting case of a 73-year-old hypertensive man with pseudoaldosteronism. He had been taking glycyrrhizin at a dose of 75 mg/day for 12 years because of mild liver damage, but had never experienced any previous symptoms associated with hypokalemia. He was referred to our hospital because of hypokalemic tetraparesis and rhabdomyolysis. At that time, we noted mineralocorticoid excess characterized by hypokalemia due to urinary K loss, exacerbation of hypertension due to increased tubular Na reabsorption, metabolic alkalosis, and suppression of both plasma renin activity and plasma aldosterone concentration. His urinary free cortisol excretion rate and the urinary ratio of free cortisol to free cortisone were markedly elevated. Thus we diagnosed pseudoaldosteronism that was related to the long-term use of glycyrrhizin. When he developed pseudoaldosteronism, he also contracted pneumonia, and exhibited elevated levels of serum cortisol and creatinine clearance (CCr) as well as hypouricemia, hypocalcemia, and hypophosphatemia. All normalized after the recovery from pneumonia and the administration of spironolactone. The extracellular volume expansion associated with increased tubular Na reabsorption by the aldosterone-sensitive distal nephron and the resulting increase in CCr caused an inhibition of proximal tubular reabsorption of uric acid, Ca, and inorganic phosphate, leading to their renal loss and therefore hypouricemia, hypocalcemia, and hypophosphatemia, respectively. In this patient, the increased circulating cortisol associated with the stress of inflammation caused by pneumonia triggered the development of pseudoaldosteronism.
Assuntos
Ácido Glicirrízico/efeitos adversos , Hidrocortisona/sangue , Hipocalcemia/etiologia , Hipofosfatemia/etiologia , Síndrome de Liddle/etiologia , Pneumonia/complicações , Idoso , Biomarcadores/sangue , Biomarcadores/urina , Humanos , Hidrocortisona/urina , Hipocalcemia/sangue , Hipocalcemia/tratamento farmacológico , Hipofosfatemia/sangue , Hipofosfatemia/tratamento farmacológico , Síndrome de Liddle/sangue , Síndrome de Liddle/tratamento farmacológico , Masculino , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Erros Inatos do Transporte Tubular Renal/sangue , Erros Inatos do Transporte Tubular Renal/tratamento farmacológico , Erros Inatos do Transporte Tubular Renal/etiologia , Fatores de Risco , Espironolactona/uso terapêutico , Fatores de Tempo , Resultado do Tratamento , Regulação para Cima , Cálculos Urinários/sangue , Cálculos Urinários/tratamento farmacológico , Cálculos Urinários/etiologiaRESUMO
The dehydriding reaction of single-phase alpha- AlH3 was investigated by in situ microscopic observations combined with thermal and surface analyses. Before the dehydriding reaction, primary AlH3 particles of size 100 nm-1 microm were thought to be covered by an oxide layer with a thickness of less than 5 nm. Both the precipitation/grain-growth of metallic Al of size 1-50 nm and an increase in 'boundary space' were clearly observed inside the particles, while the morphologies of the particles covered by the layer did not change during the dehydriding reaction. This preliminary report provides fundamental information for a further study of AlH3 as a possible hydrogen storage material.
Assuntos
Alumínio/química , Cristalização/métodos , Hidrogênio/química , Hidrogênio/isolamento & purificação , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Simulação por Computador , Substâncias Macromoleculares/química , Teste de Materiais , Modelos Químicos , Conformação Molecular , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
A 63-year-old man was admitted to our hospital for evaluation of generalized edema. Coexistence of severe hypothyroidism and nephrotic syndrome was detected by laboratory examination. High titer of both antimicrosomal antibody and antithyroid peroxidase antibody indicated Hashimotoâs disease. Renal biopsy showed minimal change glomerular abnormality, but no findings of membranous nephropathy. A series of medical treatments, including steroid therapy, thyroid hormone and human albumin replacement therapy, were administered. However, acute renal failure accompanied by hypotension, was not sufficiently prevented. After 9 sessions of plasmapheresis therapy, the severe proteinuria and low serum albumin levels were improved. Even after resting hypotension was normalized, neither renal function nor thyroid function were fully recovered. After discharge, renal function gradually returned to normal, and the blood pressure developed into a hypertensive state concomitant with the normalization of thyroid function. This report is a rare case of autoimmune thyroid disease complicated with minimal change nephrotic syndrome. In most cases of nephritic syndrome, acute renal failure (ARF) has been reported to coexist with hypertension. Although pseudohypothyroidism is well-known in nephrotic pathophysiology, complications of actual hypothyroidism are uncommon. It is suggested that the development of hypotension and ARF could be enhanced not only by hypoproteinemia, but also by severe hypothyroidism.
Assuntos
Injúria Renal Aguda/etiologia , Doença de Hashimoto/complicações , Nefrose Lipoide/etiologia , Injúria Renal Aguda/patologia , Injúria Renal Aguda/terapia , Biópsia , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Nefrose Lipoide/patologia , Nefrose Lipoide/terapia , Plasmaferese/métodosRESUMO
Ureteral obstruction causes impaired salt wastage and K+ secretion in the distal nephron segments, including the cortical collecting duct (CCD). Recently, we demonstrated that conductances of Na+ and K+ in the apical membrane, as well as the electrogenic Na(+)-K+ pump activity and the relative K+ conductance in the basolateral membrane of the collecting duct cell, were inhibited in the obstructed kidney after unilateral ureteral obstruction (UUO). To examine whether the increased intrarenal pressure might be causally related to these abnormalities in the CCD, the effects of unilateral renal decapsulation, a maneuver that partially blocks the increase in renal pressure, were evaluated with microelectrode techniques in isolated CCDs from UUO and sham-operated (control) rabbits 24 h after operation. Renal decapsulation had no effects on barrier voltages and conductances in the CCD from control animals. The lumen-negative transepithelial (VT) and basolateral membrane (VB) voltages as well as the transepithelial (GT) and the apical membrane (GA) conductances were decreased in the CCD from UUO animals compared with control animals. Pretreatment of renal decapsulation partially corrected the decreases in VT, VB, GT, and GA seen in the CCD from UUO animals. The changes in apical membrane voltage and GT upon addition of luminal amiloride and Ba2+, and the changes in VB upon addition of bath ouabain, were also decreased in the CCD from UUO animals compared with control animals. Pretreatment of renal decapsulation also partially corrected the above abnormalities seen in UUO animals, whereas it had no effect in control animals. The transference numbers for Cl- (tCl) and K+ (tK) in the basolateral membrane were, respectively, increased and decreased in the CCD from UUO animals compared with control animals. Pretreatment of renal decapsulation also partially corrected the changes in tCl and tK seen in UUO animals, whereas it had no effect in control animals. We conclude that, in UUO animals, renal decapsulation partially corrects the inhibition of apical Na+ and K+ conductances as well as basolateral Na(+)-K+ pump activity and relative K+ conductance seen after UUO, whereas in control animals it has no effect. The increased renal pressure may partly contribute to the defects in Na+ and K+ transport in the CCD from obstructed kidneys. Renal decapsulation has protective effects on impaired Na+ and K+ transports in the CCD after ureteral obstruction.
Assuntos
Córtex Renal/fisiopatologia , Túbulos Renais Coletores/fisiopatologia , Potássio/metabolismo , Sódio/metabolismo , Obstrução Ureteral/fisiopatologia , Animais , Transporte Biológico , Feminino , Tamanho do Órgão , Coelhos , ATPase Trocadora de Sódio-PotássioRESUMO
The cortical collecting tubule is one of the main nephron sites where mineralocorticoids and a high potassium diet modulate sodium (Na) and potassium (K) transport. In this study we explored the steroid-independent effects of a high K diet on the electrical transport properties of the isolated rabbit cortical collecting tubule principal cells. The electrophysiological analysis included transepithelial and single-cell potential measurements and equivalent circuit analysis. Rabbits were adrenalectomized (ADX) and received either a control diet (300 meq K/kg diet) or a high K diet (600 meq/kg diet) for 10 d before the experiment. The mean plasma K of ADX control animals was 6.9 mM, that of ADX animals on the high K diet 8.3 mM. The transepithelial potential difference was significantly elevated in the high K group (-3.5 mV, lumen negative), compared with ADX controls (-1.4 mV). The basolateral membrane potential in high K animals was also significantly elevated (-73 mV, cell negative, compared with -63 mV in controls). Estimates of the apical membrane partial Na and K conductances (GaNa and GaK) and of ion currents (IaNa and IaK) also demonstrated stimulation by the high K diet. In the high K group, both GaNa and GaK (0.56 and 2.67 mS.cm-2) were higher than control values (0.27 and 1.17 mS.cm-2). IaNa and IaK were also higher in high K animals (47.8 and -26.2 microA.cm-2) compared with control animals (22.4 and -11.6 microA.cm-2). Thus, a high K intake per se can induce electrophysiological changes consistent with stimulation of Na reabsorption and K secretion.
Assuntos
Córtex Renal/fisiologia , Túbulos Renais Coletores/fisiologia , Túbulos Renais/fisiologia , Potássio/farmacologia , Adrenalectomia , Aldosterona/metabolismo , Animais , Transporte Biológico , Membrana Celular/fisiologia , Dieta , Condutividade Elétrica , Eletrofisiologia , Potenciais da Membrana , Coelhos , Sódio/metabolismoRESUMO
Electrophysiological techniques were used to determine the electrical properties of the collecting duct (CD) cell in the isolated cortical collecting duct from obstructed (UUOOK) and contralateral (UUOCK) kidneys in rabbits 24 h after unilateral ureteral obstruction (UUO); results were compared with those from sham-operated kidneys. The lumen-negative transepithelial voltage and the basolateral membrane voltage (VB) were decreased in the UUOOK, and increased in the UUOCK. The transepithelial conductance (GT) was decreased in parallel with an increase in the fractional apical membrane resistance (fRA) and a decrease in apical membrane conductance in the UUOOK. By contrast, the GT was increased in parallel with increases in apical and basolateral membrane conductances in the UUOCK. The amiloride-sensitive changes in apical membrane voltage (VA), GT and fRA were lower in the UUOOK, but greater in the UUOCK. The changes in VA and GT upon raising the perfusate K+ concentration and upon addition of luminal Ba2+ were decreased in the UUOOK, and increased in the UUOCK. Addition of ouabain to the bath resulted in a smaller depolarization of VB in the UUOOK, but in a greater depolarization in the UUOCK. Upon lowering bath Cl-, the change in basolateral membrane electromotive force (delta EMF) was increased in the UUOOK, and decreased in the UUOCK. Reversely, upon raising bath K+, the delta EMF was decreased in the UUOOK, and increased in the UUOCK. We conclude: (a) the conductances of Na+ and K+ in the apical membrane, and active Na(+)-K+ pump activity and relative K+ conductance in the basolateral membrane are decreased in the UUOOK, and increased in the UUOCK; (b) the relative basolateral membrane Cl- conductance was increased in the UUOOK, and decreased in the UUOCK.
Assuntos
Córtex Renal/fisiologia , Córtex Renal/fisiopatologia , Túbulos Renais Coletores/fisiologia , Túbulos Renais Coletores/fisiopatologia , Obstrução Ureteral/fisiopatologia , Amilorida/farmacologia , Animais , Peso Corporal , Membrana Celular/efeitos dos fármacos , Membrana Celular/fisiologia , Condutividade Elétrica/efeitos dos fármacos , Epitélio/efeitos dos fármacos , Epitélio/fisiologia , Feminino , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Tamanho do Órgão , Ouabaína/farmacologia , Potássio/metabolismo , Potássio/farmacologia , Coelhos , Valores de ReferênciaRESUMO
Microelectrode techniques were used to determine the Na+ and K+ transport properties of the collecting duct cell in the isolated cortical collecting duct (CCD) from rabbits 14 d after uninephrectomy (UNX); results were compared with those from sham-operated rabbits (control). UNX had no effects on plasma aldosterone levels. The CCDs from UNX rabbits exhibited structural hypertrophy. The lumen negative transepithelial voltage and the basolateral membrane voltage (VB) were elevated in the UNX group. Although the transepithelial conductance (GT) and the fractional apical membrane resistance (fRA) were not different between the two groups, the conductances of the apical and the basolateral membranes were increased, and the tight junction conductance was decreased in the UNX group. The amiloride-sensitive changes in apical membrane voltage (VA), fRA, and GT were greater in the UNX group. The changes in VA upon raising the perfusate K+ concentration and the changes in VA and GT upon addition of Ba2+ to the perfusate were elevated in the UNX group. Upon raising K+ in the bath, a large depolarization of VB was observed in the UNX group. Lowering the bath Cl- resulted in a small depolarization of VB in the UNX group. Addition of Ba2+ to the bath in the UNX group caused the VB to hyperpolarize in parallel with decreases in GT and fRA whereas in the control group it had no effect on VB. Addition of ouabain to the bath resulted in a large depolarization of VB in the UNX group. We conclude that (a) UNX stimulates conductances of Na+ and K+ in the apical membrane, active Na(+)-K+ pump activity, and K+ conductance in the basolateral membrane, independently of plasma aldosterone; (b) The basolateral membrane in the tubules of UNX rabbits is more selective to K+; and (c) the hyperpolarization of VB upon UNX may increase passive K+ entry into the cell across the basolateral membrane.
Assuntos
Córtex Renal/metabolismo , Túbulos Renais Coletores/metabolismo , Nefrectomia , Potássio/metabolismo , Sódio/metabolismo , Aldosterona/sangue , Animais , Bovinos , Feminino , Túbulos Renais Coletores/fisiologia , Coelhos , ATPase Trocadora de Sódio-Potássio/análiseRESUMO
Microelectrode techniques were used to assess the electrical properties of the collecting duct cell in the isolated perfused cortical collecting duct from remnant kidneys 3, 6, and 24 h after uninephrectomy (UNX); results were compared with those from sham-operated kidneys. Plasma aldosterone levels did not change during the time course after UNX. The lumen-negative transepithelial voltage was elevated significantly 3 h after UNX, and was increased further 24 h after UNX. The basolateral membrane voltage (VB) was elevated 6 h after UNX, and then was increased further at 24 h. Although the tight junction conductance and the fractional apical membrane resistance (fRA) were not altered at any time points after UNX, the apical membrane conductance as well as the transepithelial (GT) and basolateral membrane conductances increased 6 and 24 h after UNX. The changes in apical membrane voltage, GT, and fRA upon addition of luminal amiloride increased just 3 h after UNX, and then remained elevated at 6 and 24 h. The changes in apical membrane voltage and GT upon addition of luminal Ba2+, the changes in VB upon addition of bath ouabain, and the changes in VB, GT, and fRA upon raising bath K+ were not influenced 3 h after UNX, but increased at 6 and 24 h. At these latter periods after UNX, the transference number of Cl- of the basolateral membrane decreased significantly, whereas the transference number of K+ of the basolateral membrane increased significantly. Simultaneously, addition of Ba2+ to the bath caused the VB to hyperpolarize in parallel with decreases in GT and fRA. We conclude: (a) the initial effect of UNX (3 h) in the collecting duct cell is an increase in apical membrane Na+ conductance; (b) the delayed effects of UNX (6 and 24 h) are increases in apical membrane K+ conductance as well as basolateral membrane Na(+)-K+ pump activity and K+ conductance; (c) the hyperpolarization of VB at 6 and 24 h after UNX may result in the decrease of the ratio of the relative Cl- conductance to the relative K+ conductance of the basolateral membrane and also may increase passive K+ entry into the cell across the basolateral membrane; (d) these time-dependent electrical changes occur independently of plasma aldosterone levels.
Assuntos
Córtex Renal/fisiologia , Túbulos Renais Coletores/fisiologia , Nefrectomia , Aldosterona/sangue , Amilorida/farmacologia , Animais , Bário/farmacologia , Peso Corporal , Membrana Celular/fisiologia , Cloretos/metabolismo , Condutividade Elétrica/efeitos dos fármacos , Eletrofisiologia/métodos , Epitélio/fisiologia , Feminino , Técnicas In Vitro , Rim/anatomia & histologia , Potenciais da Membrana , Tamanho do Órgão , Ouabaína/farmacologia , Potássio/sangue , Coelhos , Sódio/sangue , Fatores de TempoRESUMO
By cable analysis and intracellular microelectrode impalement in the in vitro perfused renal tubule, we identified alpha- and beta-intercalated (IC) cells along the rabbit distal nephron segments, including the connecting tubule (CNT), the cortical collecting duct (CCD), and the outer medullary collecting duct in the inner stripe (OMCDi). IC cells were distinguished from collecting duct (CD) cells by a relatively low basolateral membrane potential (VB), a higher fractional apical membrane resistance, and apparent high Cl- conductances of the basolateral membrane. Two functionally different subtypes of IC cells in the CCD were identified based on different responses of VB upon reduction of the perfusate Cl- from 120 to 12 mM: the basolateral membrane of beta-IC cells was hyperpolarized, whereas that of alpha-IC cells was unchanged. This is in accord with the hypothesis that the apical membrane of beta-IC cells contains some Cl(-)-dependent entry processes, possibly a Cl-/HCO3- exchanger. Further characterization of electrical properties of both subtypes of IC cells were performed upon lowering bath or perfusate Cl- from 120 to 12 mM, and raising bath or perfusate K+ from 5 to 50 mM. A 10-fold increase in the perfusate K+ had no effect on VB in both subtypes of IC cells. Upon abrupt changes in Cl- or K+ concentration in the bath, a large or a small depolarization of the basolateral membrane, respectively, was observed in both subtypes of IC cells. The electrical properties of alpha- and beta-IC cells were similar among the distal nephron segments, but their distribution was different: in the CNT, which consists of IC cells and CNT cells, 97.3% (36/37) of IC cells were of the beta type. In the CCD, which consists of IC cells and CD cells, 79.8% (79/99) of IC cells were of the beta-type, whereas in the OMCDi 100% (19/19) were of the alpha type, suggesting that the beta type predominates in the earlier and the alpha type in the later segment.
Assuntos
Túbulos Renais Coletores/citologia , Túbulos Renais Distais/citologia , Animais , Membrana Celular/fisiologia , Membrana Celular/ultraestrutura , Condutividade Elétrica , Eletrofisiologia , Células Epiteliais , Epitélio/fisiologia , Túbulos Renais Coletores/fisiologia , Túbulos Renais Distais/fisiologia , Potenciais da Membrana , Microeletrodos , CoelhosRESUMO
We have previously demonstrated that RACTK1 cDNA encodes a pH sensitive K+ channel expressed in the apical side of renal collecting tubule cells. To determine whether extracellular pH induces the RACTK1 gene expression in the renal cortical collecting duct (CCD) cells, we measured mRNA of the RACTK1 using cultured rabbit CCD cells. Alkalization of incubation medium activated the transcription of the RACKTK1 gene in a time- and dose-dependent manner after 1 h, and reached a maximal level after 12 h. To examine whether the stimulation of mRNA by alkalization of body fluid occurs also in vivo, mRNA levels were measured in mice loaded with acid or alkali. The RACTK1 mRNA was increased in association with the rise in urinary pH. To examine side face of the effect of pH on stimulation of mRNA, we observed the effect of pH in the apical or the basolateral side in the preparation where CCD cells were cultured on filter membrane supports. Alkalization of the apical side but not of the basolateral side, was shown to be a determinant in inducting the RACTK1 mRNA. These findings suggest that, in addition to rapid direct regulation of RACTK1 K+ channel conductance by intracellular pH, this channel is also regulated by the changes in luminal pH through synthesis of channel protein by transcriptional activation.
Assuntos
Concentração de Íons de Hidrogênio , Túbulos Renais Coletores/fisiologia , Rim/fisiologia , Canais de Potássio/biossíntese , Ativação Transcricional , Animais , Sequência de Bases , Western Blotting , Membrana Celular/fisiologia , Células Cultivadas , Cicloeximida/farmacologia , Primers do DNA , Sondas de DNA , Dactinomicina/farmacologia , Rim/metabolismo , Túbulos Renais Coletores/metabolismo , Cinética , Masculino , Camundongos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , RNA Mensageiro/biossíntese , Coelhos , Transcrição Gênica/efeitos dos fármacosRESUMO
We report a case of a 17-year-old male with relapse of minimal-change nephrotic syndrome (MCNS), in whom apheresis monotherapy without steroids or immunosuppressants resulted in complete remission. The patient initially developed nephrotic syndrome in February 1998. The first renal biopsy confirmed the diagnosis of MCNS. The patient was also found to be a carrier of hepatitis B virus. Steroid therapy was started with oral prednisolone 60 mg/day. Complete remission was achieved in 3 months, and the steroid treatment was tapered off in May 2001. During the steroid tapering, temporal exacerbation of liver function was noted. In July 2002, the patient was admitted to our hospital again due to relapse of nephrotic syndrome. Second biopsy reconfirmed the diagnosis of MCNS. Since the serum titer of HBV was elevated, apheresis monotherapy was selected to avoid the risk of steroid-induced fulminant hepatitis. Four sessions of low-density lipoprotein apheresis (LDL-A) and 5 sessions of double-filtration plasmapheresis (DFPP) reduced the proteinuria from 9.2 g/day to 0.2 g/day over 38 days without any additional medication. Proteinuria remained suppressed below 0.2 g/day for more than 12 months and no exacerbation of liver function was observed up to the final follow-up in September 2003. The present case suggested the potential of apheresis monotherapy to induce and maintain complete remission of MCNS and an important role of circulating factors in the pathogenesis of MCNS.
Assuntos
Remoção de Componentes Sanguíneos , Nefrose Lipoide/terapia , Adolescente , Biópsia , Remoção de Componentes Sanguíneos/métodos , Humanos , Rim/patologia , Rim/ultraestrutura , Masculino , Proteinúria/terapia , Indução de Remissão/métodos , Prevenção Secundária , Albumina Sérica/análiseRESUMO
Tubulointerstitial nephritis is a well-recognized complication in primary Sjögrens syndrome. Fanconi's syndrome is a far less frequent complication compared with distal tubular dysfunction. We here describe a 49-year-old woman with primary Sjögren's syndrome. In 1997, she was diagnosed with primary Sjögren's syndrome with tubulointerstitial nephritis, and was then treated with oral prednisolone for the tubulointerstitial nephritis. In 2002, she was referred to our hospital because of progressive fatigue. At that time, biclonal spike on serum protein (IgG-kappa and IgA-kappa) and Bence-Jones protein in urine were found. Bone marrow aspiration showed 1.0% plasma cell infiltration. Thus, a diagnosis of monoclonal gammopathy of undetermined significance (MGUS) was made. In 2004, she was again admitted to our hospital because of mild renal dysfunction and hypokalemia. Laboratory evaluation showed inappropriate, alkaline urine in hyperchloremic metabolic acidosis and a positive urine anion gap, indicating the presence of distal (Type 1) renal tubular acidosis (RTA). The urine concentration defect was also found. Further studies revealed proximal tubular dysfunction, including renal glycosuria, generalized aminoaciduria, phosphaturia, uricosuria and proximal RTA. The kidney biopsy represented diffuse and severe tubulointerstitial nephritis with dense infiltrates of lymphocytes and IgA and K light chain-positive plasma cells. No findings of multiple myeloma or malignant lymphoma were observed. In conclusion, our patient had Sjögren's syndrome with MGUS and exhibited dysfunction of both proximal tubule (Fanconi's syndrome) and distal tubule, which may be attributed to diffuse tubulointerstitial nephritis.
Assuntos
Acidose Tubular Renal/complicações , Síndrome de Fanconi/diagnóstico , Paraproteinemias/diagnóstico , Síndrome de Sjogren/sangue , Síndrome de Sjogren/complicações , Acidose Tubular Renal/diagnóstico , Biópsia , Feminino , Humanos , Rim/patologia , Rim/ultraestrutura , Pessoa de Meia-IdadeRESUMO
Despite the crucial role of calcium in myocardial contractility, hypocalcemia has very rarely been reported as a reversible cause of heart failure. In this article, we describe a case of a 51-year-old woman with advanced stages of chronic renal failure after parathyroidectomy who exhibited congestive heart failure, severe hypocalcemia, hypomagnesemia and hypokalemia. Severe hypocalcemia resulted from discontinuation of taking calcium supplements after parathyroidectomy and from reduced 1.25(OH)2D3 synthesis by damaged kidneys. The patient presented with reduced left ventricular ejection fraction (EF) and ECG abnormalities (T wave alternans and increased QTc dispersion), both of which improved after correction of serum calcium levels. Her serum levels of total calcium corrected for serum albumin, but not serum levels of magnesium or potassium, positively and negatively correlated with EF and QTc dispersion, respectively. In the present case, both heart failure and the ECG abnormalities are directly associated with hypocalcemia.
Assuntos
Eletrocardiografia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Hipocalcemia/complicações , Falência Renal Crônica/complicações , Paratireoidectomia , Cálcio/sangue , Feminino , Humanos , Hipocalcemia/etiologia , Hipocalcemia/fisiopatologia , Hipopotassemia/etiologia , Magnésio/sangue , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Potássio/sangue , Volume SistólicoRESUMO
Mechanisms for multifocal bladder carcinogenesis remain unclear. To see whether normal mucosa had already acquired genetic or epigenetic changes, we examined loss of heterozygosity (LOH) at 10 microsatellite loci and methylation of the p16(INK4) CpG island in multiple tumors and pathologically normal mucosa in six patients with bladder cancer. Either LOH or methylation was detected in 77% of samples of normal epithelium, and LOH detected in samples of normal epithelium was also observed in most tumor samples. This result indicated that a population of cells in morphologically normal epithelium possessed genetic or epigenetic aberrations in common with bladder cancer, which might provide a ground for multiple tumorigenesis.