The impact of predisposing factors on long-term outcome after stroke in diabetic patients: the Fukuoka Stroke Registry.

BACKGROUND AND PURPOSE: Although stroke patients with diabetes mellitus have a poor prognosis, the prognostic factors of patients with diabetes mellitus have not been adequately studied. The aim of this study was to determine the predisposing factors for outcome 1 year after stroke in diabetic patients. METHODS: Patients' characteristics, findings on admission and outcome 1 year after first ischaemic stroke were prospectively investigated in 452 consecutive patients with diabetes mellitus (305 males, 147 females; 69 ±â€…10 years old). A poor outcome was defined as a modified Rankin Scale (mRS) score ≥ 2, 1 year after stroke onset. RESULTS: There were 286 patients with a good outcome (mRS score ≤ 1) and 166 with a poor outcome (mRS score ≥ 2). On multivariate logistic regression analysis, age [odds ratio (OR) 1.06, 95% confidence interval (CI) 1.03-1.10, P < 0.001, per 1-year increase], National Institutes of Health Stroke Scale (NIHSS) score on admission (OR 1.21, 95% CI 1.11-1.32, P < 0.001, per 1-point increase), diabetic nephropathy (OR 1.93, 95% CI 1.02-3.65, P = 0.044) and hemoglobin A1c (HbA1c; OR 1.27, 95% CI 1.07-1.51, P = 0.007, per 1% increase) were independently related to poor outcome (mRS score ≥ 2) 1 year after the onset of the first stroke in diabetic patients. CONCLUSIONS: In stroke patients with diabetes mellitus, age, NIHSS score on admission, diabetic nephropathy and HbA1c were independently associated with a poor outcome 1 year after the first ischaemic stroke.

Proteinuria and clinical outcomes after ischemic stroke.

OBJECTIVES: The impact of chronic kidney disease (CKD) on clinical outcomes after acute ischemic stroke is still not fully understood. The aim of the present study was to elucidate how CKD and its components, proteinuria and low estimated glomerular filtration rate (eGFR), affect the clinical outcomes after ischemic stroke. METHODS: The study subjects consisted of 3,778 patients with first-ever ischemic stroke within 24 hours of onset from the Fukuoka Stroke Registry. CKD was defined as proteinuria or low eGFR (<60 mL/min/m(2)) or both. The study outcomes were neurologic deterioration (≥2-point increase in the NIH Stroke Scale during hospitalization), in-hospital mortality, and poor functional outcome (modified Rankin Scale score at discharge of 2 to 6). The effects of CKD, proteinuria, and eGFR on these outcomes were evaluated using a multiple logistic regression analysis. RESULTS: CKD was diagnosed in 1,320 patients (34.9%). In the multivariate analyses after adjusting for confounding factors, patients with CKD had significantly higher risks of neurologic deterioration, in-hospital mortality, and poor functional outcome (p <0.001 for all). Among the CKD components, a higher urinary protein level was associated with an elevated risk of each outcome (p for trend < 0.001 for all), but no clear relationship between the eGFR level and each outcome was found. CONCLUSIONS: CKD is an important predictor of poor clinical outcomes after acute ischemic stroke. Proteinuria independently contributes to the increased risks of neurologic deterioration, mortality, and poor functional outcome, but the eGFR may not be relevant to these outcomes.

Polymorphism in the sorbin and SH3-domain-containing-1 (SORBS1) gene and the risk of brain infarction in the Japanese population: the Fukuoka Stroke Registry and the Hisayama study.

BACKGROUND AND PURPOSE: Sorbin and SH3-domain-containing-1 (SORBS1) is an important adaptor protein in insulin-signalling pathway, and its genetic polymorphism may regulate the activity of insulin resistance. We investigated the association between the SORBS1 T228A polymorphism and ischaemic stroke. METHODS: Genotyping was achieved by a rapid-cycle PCR and melting curve analysis using fluorescent probes in 1049 incident cases of ischaemic stroke and 1049 age- and sex-matched control subjects recruited from the Hisayama study. RESULTS: The allele distributions of the SORBS1 T228A polymorphism were similar amongst cases and controls. The multivariate-adjusted odds ratio (OR) of the AA genotype for ischaemic stroke was 2.897 (95% CI, 0.907-8.018) compared with the TT genotype. In terms of stroke subtype, there was a trend toward a difference in the AA genotypes for lacunar infarction, compared with the TT genotype (OR = 8.740, P = 0.0510), and combined TT and TA genotypes (OR = 8.768, P = 0.0505). The other polymorphisms genotyped were not associated with any subtypes of ischaemic stroke. T228A polymorphism of SORBS1 was not associated with the prevalence of diabetes. CONCLUSIONS: The AA genotype of SORBS1 T228A polymorphism may play a role in lacunar infarction in the Japanese population.

NAD(P)H oxidase p22phox C242T polymorphism and ischemic stroke in Japan: the Fukuoka Stroke Registry and the Hisayama study.

The C242T polymorphism of p22phox, a component of NAD(P)H oxidase, may have an impact on cardiovascular diseases; however, the association between this polymorphism and brain infarction is not fully understood. Here, we investigate the relationship between the C242T polymorphism and brain infarction in Japan. We recruited 1055 patients with brain infarction and 1055 control subjects. A chi-squared test revealed that the T-allele frequency was lower in patients with cardioembolic infarction (5.6%) than in control subjects (11.0%, P < 0.001); however, allele frequencies in patients with lacunar and atherothrombotic infarction (11.2%) were not significantly different from those in control subjects (11.0%). A multivariate-adjusted conditional logistic regression analysis also revealed no association between CT + TT genotype, and lacunar and atherothrombotic infarction (odds ratio = 0.97, 95% confidence interval: 0.72-1.32). To investigate the functional effects of the C242T polymorphism, we examined superoxide production in COS-7 cells cotransfected with Nox4 and p22phox of each genotype. The superoxide-producing activity in those cells expressing p22phox with the T allele was not significantly different from that in cells expressing p22phox with the C allele. The present results suggest that the p22phox C242T polymorphism may have a protective effect against cardioembolic infarction, but is not related to lacunar and atherothrombotic infarction in Japan.

Transoral ultrasonographic evaluation of carotid flow in predicting cerebral hemodynamics after carotid endarterectomy.

PURPOSE: We investigated whether measurement of blood flow in the extracranial distal internal carotid artery (ICA) by transoral carotid ultrasonography (TOCU) can predict the cerebral hemodynamics and the hemodynamic effect of carotid endarterectomy (CEA) in patients with unilateral carotid stenosis. METHODS: Forty-nine patients with unilateral ICA stenosis who underwent CEA were studied. Preoperative blood flow in the poststenotic portion of the extracranial ICA was studied by using TOCU. Regional cerebral blood flow (rCBF) and vasoreactivity to acetazolamide (VR) in the territory of the middle cerebral artery were investigated by using single-photon emission CT (SPECT) before, 2 weeks after, and 3 months after CEA. RESULTS: Doppler flow velocities in the extracranial distal ICA measured transorally by TOCU correlated with baseline as well as postacetazolamide rCBF in the ipsilateral side (regression analysis, P < .05). Diameter and blood flow volume in the extracranial distal ICA were associated with ipsilateral postacetazolamide rCBF and VR (regression analysis, P < .05). When the patients were divided into 2 groups according to the ICA volume flow distal to a carotid stenosis, group I < 3.5 mL/s and group II > 3.5 mL/s, ipsilateral postacetazolamide rCBF in group I was significantly lower than that in group II (P = .008). Ipsilateral postacetazolamide rCBF (analysis of variance [ANOVA], P = .02) and VR (ANOVA, P = .03) significantly improved after CEA for 3 months in group I but not in group II. CONCLUSION: TOCU can detect the decrease in poststenotic flow of the distal extracranial ICA that is indicative of impaired intracranial hemodynamics and predictive for improvement of cerebral blood flow after CEA in patients with unilateral carotid stenosis.

Antiplatelet therapy contributes to acute deterioration of intracerebral hemorrhage.

OBJECTIVE: The purpose of this study was to examine the effect of antiplatelet therapy on the initial severity and the acute outcome of intracerebral hemorrhage (ICH). METHODS: The authors reviewed records of 251 consecutive patients hospitalized in their cerebrovascular center within 24 hours after onset of ICH. RESULTS: Fifty-seven patients (23%) had development of ICH during oral antiplatelet therapy. The major indication for antiplatelet therapy was the prevention of stroke recurrence (63%). As compared with patients without antiplatelet therapy, those who received antiplatelet therapy more frequently were aged 70 years or older (60% vs 35%; p < 0.001), had previous symptomatic ischemic stroke (54% vs 7%; p < 0.0001), had diabetes mellitus (26% vs 15%; p < 0.05), and had heart disease (32% vs 8%; p < 0.0001). Antiplatelet therapy was predictive of an increase in the hematoma volume by more than 40% on the second hospital day (hematoma enlargement, odds ratio [OR] 7.67, 95% CI 1.62 to 36.4) and the need for emergent surgical evacuation of the hematoma (OR 3.10, 95% CI 1.18 to 8.15). Antiplatelet therapy was an independent predictor for the occurrence of any of hematoma enlargement, emergent death, or evacuation surgery, which suggests that clinical deterioration occurs into the second hospital day (OR 7.45, 95% CI 2.46 to 22.5). CONCLUSIONS: Antiplatelet therapy seems to contribute to the acute clinical deterioration of intracerebral hemorrhage.

Role of Na(+)/H(+) exchanger in dilator responses of rat basilar artery in vivo.

We tested the hypothesis that activation of Na(+)/H(+) exchanger is involved in dilator responses of the basilar artery to endothelium-dependent vasodilators in vivo. Using a cranial window in anesthetized rats, we examined responses of the basilar artery to acetylcholine and bradykinin. Topical application of acetylcholine and bradykinin increased diameter of the basilar artery in a concentration-related manner. Because N(G)-nitro-L-arginine, an inhibitor of nitric oxide synthase, almost abolished vasodilator responses to acetylcholine and bradykinin, vasodilatation produced by the agonists appears to be mediated primarily by nitric oxide. 5-N,N-Hexamethyleneamiloride, an inhibitor of Na(+)/H(+) exchanger, did not affect baseline diameter of the basilar artery, but inhibited vasodilatation in response to acetylcholine and bradykinin, without affecting vasodilatation produced by sodium nitroprusside. FR183998, another inhibitor of Na(+)/H(+) exchanger, also attenuated acetylcholine-induced dilatation of the basilar artery without affecting vasodilatation in response to sodium nitroprusside. Monomethylamine hydrochloride, which produces intracellular alkalinization, enhanced acetylcholine-induced dilatation of the basilar artery in the presence of 5-N,N-hexamethyleneamiloride. These results suggest that intracellular alkalinization produced by activation of Na(+)/H(+) exchanger may enhance nitric oxide production in the basilar arterial endothelium and thereby contribute to dilator responses of the artery in vivo.

Role of phosphatidylinositol 3-kinase in acetylcholine-induced dilatation of rat basilar artery.

BACKGROUND AND PURPOSE: We tested the hypothesis that activation of phosphatidylinositol (PI) 3-kinase is involved in dilator responses of the basilar artery to acetylcholine in vivo. METHODS: Responses of the basilar artery were measured by the cranial window technique in anesthetized rats. To examine the role of PI 3-kinase in acetylcholine-induced calcium signaling, we measured intracellular free calcium concentration ([Ca(2+)](i)) of cultured rat basilar arterial endothelial cells using a fluorescent calcium indicator, indo 1. RESULTS: -Topical application of acetylcholine (10(-6), 10(-5.5), and 10(-5) mol/L) increased the diameter of the basilar artery by 8+/-1%, 14+/-2%, and 24+/-3%, respectively. An inhibitor of PI 3-kinase, wortmannin (10(-8) mol/L), did not change the baseline diameter of the artery. In the presence of wortmannin, acetylcholine (10(-6), 10(-5.5), and 10(-5) mol/L) dilated the artery only by 3+/-2%, 6+/-2%, and 12+/-2%, respectively. Thus, wortmannin attenuated acetylcholine-induced dilatation of the basilar artery (P<0.05 versus control). Wortmannin had no effect on dilatation of the artery in response to a nitric oxide donor, sodium nitroprusside. LY294002, another inhibitor of PI 3-kinase, also inhibited dilator response of the basilar artery to acetylcholine. Acetylcholine produced an increase in [Ca(2+)](i) of the endothelial cells. Genistein, an inhibitor of tyrosine kinase, markedly attenuated acetylcholine-induced calcium influx to the cells; however, wortmannin had no effect on acetylcholine-induced calcium changes. CONCLUSIONS: These results suggest that acetylcholine-induced dilatation of the basilar artery is mediated, at least in part, by activation of PI 3-kinase in vivo. Acetylcholine-induced [Ca(2+)](i) changes of the endothelial cells may not be mediated by activation of the kinase. PI 3-kinase as well as [Ca(2+)](i) may play an important role in the acetylcholine-induced nitric oxide production of the basilar arterial endothelial cells.

Membrane potential as a modulator of the free intracellular Ca2+ concentration in agonist-activated endothelial cells.

We have used combined patch clamp and fura-2 fluorescence to elucidate the role of membrane potential in the regulation of the cytosolic Ca2+ concentration ([Ca2+]i) in a human umbilical vein derived endothelial cell-line, EA.hy926 (EA cells) stimulated with vasoactive agonists, such as ATP, histamine and bradykinin. This stimulation caused hyperpolarization and sustained Ca2+ plateau in nonclamped cells. Clamping agonist-stimulated cells at negative potentials enhanced the amplitude of this plateau, whereas it was smaller at more depolarized potentials, indicating that Ca2+ influx follows its driving force. Depolarization of the membrane by increasing extracellular K+ or by applying charybdotoxin, a blocker of big conductance Ca2+-dependent K+ channels during agonist stimulation diminished the plateau rise in [Ca2+]i. It is concluded that the membrane potential is an efficient regulator of Ca2+ influx during the plateau phase of agonist-mediated Ca2+ signals. In addition, the modulating effects on Ca2+ signals should be interpreted with caution if the membrane potential of the cells is not controlled.

Properties of heterologously expressed hTRP3 channels in bovine pulmonary artery endothelial cells.

1. We combined patch clamp and fura-2 fluorescence methods to characterize human TRP3 (hTRP3) channels heterologously expressed in cultured bovine pulmonary artery endothelial (CPAE) cells, which do not express the bovine trp3 isoform (btrp3) but express btrp1 and btrp4. 2. ATP, bradykinin and intracellular InsP3 activated a non-selective cation current (IhTRP3) in htrp3-transfected CPAE cells but not in non-transfected wild-type cells. During agonist stimulation, the sustained rise in [Ca2+]i was significantly higher in htrp3-transfected cells than in control CPAE cells. 3. The permeability for monovalent cations was PNa > PCs approximately PK >> PNMDG and the ratio PCa/PNa was 1.62 +/- 0.27 (n = 11). Removal of extracellular Ca2+ enhanced the amplitude of the agonist-activated IhTRP3 as well as that of the basal current The trivalent cations La3+ and Gd3+ were potent blockers of IhTRP3 (the IC50 for La3+ was 24.4 +/- 0.7 microM). 4. The single-channel conductance of the channels activated by ATP, assessed by noise analysis, was 23 pS. 5. Thapsigargin and 2,5-di-tert-butyl-1, 4-benzohydroquinone (BHQ), inhibitors of the organellar Ca2+-ATPase, failed to activate IhTRP3. U-73122, a phospholipase C blocker, inhibited IhTRP3 that had been activated by ATP and bradykinin. Thimerosal, an InsP3 receptor-sensitizing compound, enhanced IhTRP3, but calmidazolium, a calmodulin antagonist, did not affect IhTRP3. 6. It is concluded that hTRP3 forms non-selective plasmalemmal cation channels that function as a pathway for agonist-induced Ca2+ influx.

Nonselective cation channels in endothelial cells derived from human umbilical vein.

(i) We have used a combined patch-clamp and fura-2 fluorescence technique to characterize a nonselective cation channel (NSC) in Ea. hy926 (EA) cells, an endothelial cell line derived from human umbilical vein. (ii) Stimulation with ATP, histamine and bradykinin activated slowly and with a long delay after application of the agonist, a nonselective cation current (INSC) which is time- and voltage-independent. The permeability sequence for cations was PNa > PCs >> PNMDG, PCa. In the absence of external Ca2+ and at rather high concentrations, La3+ and Gd3+ blocked INSC. (iii) Single channel analysis revealed that ATP activates in the cell-attached configuration a nonselective cation channel with a conductance of approximately 24 pS and a permeation sequence identical to that of the macroscopic current. The channel activity disappeared after membrane excision. (iv) Activation of NSC required physiological intracellular Ca2+ levels (100 nm or higher). All agonists failed to activate NSC if cytosolic Ca2+ ([Ca2+]i) was lowered by 10 mm BAPTA. Clamping internal Ca2+ at 1 microm sometimes (8 out of 17 cells) spontaneously activated INSC in the absence of any additional stimulus. (v) Application of 2,5-di-tert-butylhydroquinone and internal perfusion of inositol 1,4,5-trisphosphate also activated INSC. The phospholipase C inhibitor, U-73122 inhibited INSC and the sustained Ca2+ plateau during agonist stimulation whereas the inactive analogue, U-73343 had no effect. (vi) These results indicate NSC may act as a Ca2+ entry pathway in endothelium. [Ca2+]i and inositol 1,4,5-trisphosphate play a role in the activation cascade of NSC, and possibly also store depletion.

Simultaneous activation of Ca(2+)-dependent K+ and Cl- currents by various forms of stimulation in the membrane of smooth muscle cells from the rabbit basilar artery.

In smooth muscle cells isolated from cerebral blood vessels, histamine activates Cl- channels through an elevation of intracellular Ca2+. We investigated whether Cl- currents were also evoked by adenosine triphosphate (ATP) or caffeine in isolated smooth muscle cells from the rabbit basilar artery using the perforated patch-clamp technique. Bath application of 10 microM ATP or 1 mM caffeine (holding potential -60 mV) activated transient inward currents. With prolonged bath application of 10 microM ATP or 1 mM caffeine, oscillatory inward current were sporadically generated. At a holding potential of -40 mV, transient Cl- currents were induced by 10 microM histamine, 10 microM ATP, and 1 mM caffeine, following activation of a K+ current. At -10 or -20 mV, histamine predominantly activated the K+ current. A repetitively activated outward current was induced by membrane depolarization. These results suggest that oscillations in intracellular Ca2+ induced by histamine, ATP, and caffeine caused Cl(-)-current activation at the resting membrane potential. This Cl- current may depolarize the membrane and, thus activate voltage-dependent currents, including a Ca(2+)-dependent K+ current. Both the Ca(2+)-dependent K+ and Cl- currents induced by various stimuli may contribute to the modulation of Ca2+ influx by reinforcing membrane depolarization.

Modulation of inwardly rectifying potassium channels in cultured bovine pulmonary artery endothelial cells.

1. We have used the patch-clamp technique to study modulation of the inwardly rectifying K+ current (IK(IR)) in cultured bovine pulmonary artery endothelial cells (CPAE cells). In whole-cell mode, IK(IR) was defined as the Ba(2+)-sensitive current. In single channel recordings, we observed a strongly inwardly rectifying and K(+)-selective channel with a conductance of 31 +/- 3 pS. 2. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and functional data suggest that the endothelial IRK is most probably Kir2.1. 3. Intracellular ATP is required to prevent run-down of IRK in whole-cell mode. Single channel activity disappeared in inside-out patches exposed to ATP-free solution and in cell-attached patches on cells exposed to metabolic inhibition (KCN, 2-deoxyglucose). 4. The non-hydrolysable ATP analogues, ATP gamma S and adenylyl imidodiphosphate (AMP-PNP), did not prevent run-down. Run-down did not occur in the presence of okadaic acid, a phosphatase inhibitor, but was enhanced in the presence of protamine, an activator of phosphatase 2A (PP2A). 5. GTP gamma S and AlF4- inhibited IRK, also in the presence of ATP. GTP beta S antagonized the GTP gamma S effect. Pretreatment of the cells with PTX did not affect the GTP gamma S-induced inhibition. Okadaic acid, however, slowed this inhibition. 6. Neither activation of protein kinase A (PKA) nor activation of protein kinase C (PKC) affected IRK. Additionally, neither cytochalasin B nor a high concentration of intracellular Ca2+ affected the time course of IRK run-down. 7. We conclude that run-down of IRK is probably due to dephosphorylation by PP2A. Activation of a PTX-insensitive G protein inhibits this current by a mechanism that is neither mediated via the PKA and PKC pathways nor by intracellular Ca2+, but supposedly by a G protein-dependent activation of a phosphatase.

Inhibition by mibefradil, a novel calcium channel antagonist, of Ca(2+)- and volume-activated Cl- channels in macrovascular endothelial cells.

1. We have studied the effects of mibefradil, a novel calcium antagonist, on the resting potential and ion channel activity of macrovascular endothelial cells (calf pulmonary artery endothelial cells, CPAE). The patch clamp technique was used to measure ionic currents and the Fura-II microfluorescence technique to monitor changes in the intracellular Ca2+ concentration, [Ca2+]i. 2. Mibefradil (10 microM) hyperpolarized the membrane potential of CPAE cells from its mean control value of -26.6 +/- 0.6 mV (n = 7) to -59.8 +/- 1.7 mV (n = 6). A depolarizing effect was observed at higher concentrations (-13.7 +/- 0.6 mV, n = 4, 30 microM mibefradil). 3. Mibefradil inhibited Ca(2+)-activated Cl- currents, ICl,Ca, activated by loading CPAE cells via the patch pipette with 500 nM free Ca2+ (Ki = 4.7 +/- 0.18 microM, n = 8). 4. Mibefradil also inhibited volume-sensitive Cl- currents, ICl,vol, activated by challenging CPAE cells with a 27% hypotonic solution (Ki = 5.4 +/- 0.22 microM, n = 6). 5. The inwardly rectifying K+ channel, IRK, was not affected by mibefradil at concentrations up to 30 microM. 6. Ca2+ entry activated by store depletion, as assessed by the rate of [Ca2+]i-increase upon reapplication of 10 mM extracellular Ca2+ to store-depleted cells, was inhibited by 17.6 +/- 6.5% (n = 8) in the presence of 10 microM mibefradil. 7. Mibefradil inhibited proliferation of CPAE cells. Half-maximal inhibition was found at 1.7 +/- 0.12 microM (n = 3), which is similar to the concentration for half-maximal block of Cl- channels. 8. These actions of mibefradil on Cl- channels and the concomitant changes in resting potential might, in addition to its effect on T-type Ca2+ channels, be an important target for modulation of cardiovascular function under normal and pathological conditions.

Membrane currents evoked by histamine in rabbit basilar artery.

The membrane current evoked by histamine in isolated smooth muscle cells from rabbit basilar artery was investigated using the perforated-patch technique. When 10 microM histamine was applied in the bath at a holding potential of -60 mV, an inward current (79.2 +/- 55.8 pA) was transiently activated. An outward current was additionally evoked by 10 microM histamine when the membrane was held at -40 mV or less negative potentials. The outward but not the inward current was completely blocked by 100 nM charybdotoxin. A higher concentration of histamine (30 microM) failed to produce the inward current (3.4 +/- 4.8 pA) when Cl- concentration in the pipette was reduced. The apparent reversal potential of the inward current induced by histamine in physiological salt solution, in high-tetraethylammonium (TEA+) solution (bath), or in low-Cl- solution (pipette) was -6.3 +/- 4.4, -7.5 +/- 4.9, or -45.8 +/- 8.5 mV, respectively. Niflumic acid (100 microM) reversibly blocked the inward current, which was also blocked by 10 microM pyrilamine but not by 10 microM cimetidine. When histamine was continuously applied in the bath, spontaneous transient inward currents were generated. Removal of external Ca2+ or addition of 1 microM nicardipine or 2 mM caffeine reduced the amplitude of the histamine-induced inward current. These results suggest that histamine induces an inward current via H1 receptors at the resting membrane potential, possibly due to activation of Cl- currents. The Cl- inward current might be generated by elevation of intracellular Ca2+ via histamine receptors. The inward current may also contribute to control of the Ca2+ influx via a change in the membrane potential.

Functional effects of expression of hslo Ca2+ activated K+ channels in cultured macrovascular endothelial cells.

The aim of the present study is to elucidate the effects of the expression of large conductance Ca2+ activated K+ channels (BK[Ca]) in an endothelial cell type normally lacking this channel. The human homologue hslo of BK(Ca) was expressed in cultured bovine pulmonary artery endothelial (CPAE) cells, which have no endogenous BK(Ca). Membrane potential, ionic currents and Ca2+ signals were investigated in non-transfected and transfected cells using a combined patch clamp and Fura-2 fluorescence technique. In non-transfected control CPAE cells, ATP evoked a Ca2+ activated Cl- current (I[Cl,Ca]). The most prominent current component during ATP stimulation in hslo expressing cells was conducted BK(Ca) which resulted in a pronounced transient hyperpolarization. This hyperpolarization, which was absent in non-transfected cells, was enhanced if I(Cl,Ca) was blocked with niflumic acid. The sustained component of the Ca2+ response during ATP stimulation was significantly larger in hslo transfected cells than in non-transfected cells. This plateau level correlated well with the corresponding effects of ATP on the membrane potential, indicating that the expression of cloned BK(Ca) exerts a positive feedback on Ca2+ signals in endothelial cells by counteracting the negative (depolarizing)effect of stimulation of Ca2+-activated Cl- channels.

[Urinary incontinence in elderly patients in the chronic stage of stroke].

One hundred and six elderly patients with chronic stroke who were admitted to Seiai Rehabilitation Hospital were studied regarding urinary incontinence. The average age of the subjects was 74 +/- 8 years old, ranging from 60 to 94 years. Seventy three of the 106 patients (69%) had urinary incontinence which was found in 72% of brain infarction, 61% of brain hemorrhage and 67% of subarachnoid hemorrhage. The prevalence of urinary incontinence in cases of brain stem, thalamic, and putaminal hemorrhage was 80%, 67% and 46%, while that in cases of cortical infarction and infarct of perforating arteries was 84% and 68%, respectively. The rate of urinary incontinence was significantly higher in those aged 75 years or over (p < 0.05), those with poor activities of daily living (ADL, p < 0.005), or with dementia (p < 0.001). Dementia was a complicating factor more frequently in aged patients (p < 0.05) and in those with poor ADL (p < 0.001), although no correlation was seen between age and ADL (p = 0.08). These results indicated the high prevalence of urinary incontinence in elderly inpatients with chronic stroke, which is significantly related to impairment of mental and physical activities.

Regulation of ATP-sensitive K+ channels by ATP and nucleotide diphosphate in rabbit portal vein.

The modulation of ATP-sensitive K+ (KATP)-channel activity was investigated by recording single-channel currents in isolated smooth muscle cells from rabbit portal vein. K(+)-channel openers (KCOs; pinacidil, lemakalim, and nicorandil) induced burstlike openings of single KATP channels in the cell-attached configuration. After patch excision, KATP channels showed "run-down" phenomenon in the presence of KCOs, but subsequent application of Mg-ATP (1 mM) restored KATP-channel activity. Removal of Mg-ATP resulted in transient augmentation of KATP currents, which eventually decayed out. Nucleotide diphosphates (NDPs; GDP, ADP, UDP, IDP, and CDP) also induced channel reopening in the presence of KCOs, which was markedly enhanced by addition of Mg2+ in millimolar concentrations at the internal side of the membrane. The dose-response relation between ATP and the UDP-induced KATP-channel activity was shifted to the right in the presence of Mg2+ (2 mM). These results suggest that intracellular ATP, NDPs, and Mg2+ regulate the channel state of KATP channels (operative and inoperative states) and that KCOs open KATP channels only in the operative state.