Uphill Accumulation of Ionic Species into a Lipid Vesicle by the Concentration Gradient of Counter Ions.

The "uphill (against the concentration gradient)" accumulation of a hydrophobic cation (rhodamine 6G, R6G+) into the inner phase of a giant unilamellar vesicle (GUV) was realized with the concentration gradient of the counter anion (X- = ClO4-, BF4-, or Br-) in the presence of phosphate buffer (P-, pH = 7) in the inner and outer phase of the GUV and detected as the increase of the R6G+ fluorescence intensity in the inner phase using a confocal laser scanning fluorescence microscope. The addition of X- in the outer phase of the GUV caused the accumulation of R6G+ in the inner phase. The degree and kinetics of the accumulation were dependent on the concentration and type of X-; e.g., the inner concentration of R6G+ reached 2.5 times that in the outer phase of GUV after adding 10 mM ClO4-. The accumulation was theoretically simulated by assuming the distribution of ion pairs (R6G+ and X-, R6G+, and P-) between the aqueous phase and the lipid bilayer membrane (ion pair distribution model) and the transmembrane fluxes of R6G+, X- and P-. The theoretical simulation rationalized the accumulation degree and kinetics of the experimental results. The accumulation of the target cation by the concentration gradient of the counter anion demonstrated in this study can be an effective method for the preparation of liposomal drugs.

Distribution of ion pairs into a bilayer lipid membrane and its effect on the ionic permeability.

This work reports the distribution constant of a target ion and a counter-ion between an aqueous phase and an artificial bilayer lipid membrane (BLM) and its influence to the ionic permeability through a BLM. A theoretical formula for ionic permeability through a BLM based on the distribution of the target ion and the counter-ion is also proposed and validated by analyzing the flux of a fluorescent cation [rhodamine 6G (R6G+)] through the BLM in the presence of counter-ions (X- = Br-, BF4-, and ClO4-). The transmembrane flux was evaluated by simultaneous measurement of the transmembrane current density and the transmembrane fluorescence intensity as a function of the membrane potential. The distribution constant of R6G+ and X- between the aqueous and BLM phases was determined by a liposome-extraction method. The measured ionic permeability exhibited non-linear dependent on the aqueous concentration of R6G+ or X-, but proportional to the concentration of R6G+ and X- inside the BLM evaluated from the distribution constant of R6G+ and X-. The proportionality demonstrates that the distribution of cations and anions between the aqueous and BLM phases dominates the flux of ion transport through the BLM. The proposed formula can express the dependence of the transmembrane current on the membrane potential and the concentrations of R6G+ and X- in the aqueous phase.

Dynamic behavior analysis of ion transport through a bilayer lipid membrane by an electrochemical method combined with fluorometry.

To examine the transport of an ionic substance through a bilayer lipid membrane (BLM), an electrochemical method combined with fluorometry was proposed. In this method, the transport of a fluorescent ion through the BLM was detected both as the transmembrane current and the dynamic change of fluorescence intensity synchronizing scanning membrane potential. The fluorescence intensity was measured in the local area close to the planar BLM by utilizing a confocal fluorescence microscope. The electrochemical method combined with fluorometry makes it possible to analyze only the transport of a target fluorescent ion in distinction from the transport of other coexisting ions. With the proposed electrochemical method, the ion transport caused by both a hydrophobic fluorescent cation (rhodamine 6G+, R6G+) and a relatively hydrophobic anion (BF4-) was examined. The electrochemical method combined with fluorometry characterized the transmembrane current as the transport of R6G+. Membrane conductance for the R6G+ transport increased proportionally to the concentrations of R6G+ and BF4- distributed in the hydrocarbon medium of the BLM which were estimated by extraction experiments with liposomes. These results show that the distribution of a cation and an anion from the aqueous phase in the BLM predominantly controls the membrane conductance for ion transport through the BLM.

Kinetic Switching of the Concentration/Separation Behavior of Microdroplets.

This work demonstrates that the solute concentration inside 100 micrometer-sized aqueous microdroplets can be controlled by adjusting the time required for the aqueous nanometer-sized droplets (nanodroplet) or reverse micelles to pass over the surface of the microdroplet. The kinetics of molecular transport between the microdroplets and the nanodroplets was investigated by utilizing a microdroplet array, and on the basis of these results, a control over the concentration selectivity of the contents of the microdroplet was achieved. This method is operationally simple and can be potentially applied as a pretreatment method for microanalytical systems that require high-density microdroplet arrays. This method can also be utilized for parallel small sample analyses such as single cell analysis.

Distribution and Adsorption of Ionic Species into a Liposome Membrane and Their Dependence upon the Species and Concentration of a Coexisting Counterion.

The distribution of ions into a bilayer lipid membrane (BLM) and their adsorption on the BLM are investigated by extracting a hydrophobic cation, rhodamine 6G (R6G+), into a liposome through the dialysis membrane method. R6G+ distribution mainly depends upon the concentration of the coexisting anion and its species (Cl-, Br-, BF4-, ClO4-, and picrate). On the other hand, R6G+ adsorption on the BLM surface follows the Langmuir adsorption model and is independent of the coexisting anion in the aqueous phase. We propose an extraction model of ionic species into the BLM, to explain the dependence of extraction of ionic species upon the coexisting anion. In this model, an ion is distributed with a coexisting counterion into the BLM and then forms an ion pair in the BLM. Here, the ion adsorption equilibrium on the BLM surface is independent of the species and concentration of the coexisting counterion under the same ionic strength. On the basis of this model, we estimate the distribution constant of R6G+ and anion (KD), the ion-pair formation constant in the BLM (Kip), and the R6G+ adsorption constant on the BLM surface (Kad). Even for an ultrathin membrane system, such as a BLM, R6G+ is distributed with a coexisting counterion and the distribution equilibrium of the ionic species at the water-BLM interface is analyzable similar to that at the water-organic solvent interface.

Improved thin-layer electrolysis cell for ion transfer at the liquid|liquid interface using a conducting polymer-coated electrode.

This article reviews the development of a thin-layer electrolysis cell with both a thin aqueous phase and a thin organic phase for ion transfer at the liquid|liquid interface for the absolute determination of a redox-inactive ion. In particular, an improvement of the cell performance by using a conducting polymer-coated electrode in the organic phase is discussed. The applicability of the thin-layer electrolysis cell to the absolute determination of redox-inactive ions using the flow-injection method or stripping method is also described.

Propagation and synchronization of potential oscillations in multiple liquid membrane systems.

Two liquid membrane oscillators composed of aqueous solutions containing cetyltrimethylammonium chloride (CTACl) and alcohol, W1 and W1', a nitrobenzene solution containing picric acid, O, and pure water phase, W2, were connected through O and W2 as common phases. Two glass tubes including W1 and W1' were inserted into the O/W2 interface. Both membrane potential differences between W1 and W2 and that between W1' and W2 were recorded using a pair of Ag/AgCl electrodes located near the orifice of each tube. The oscillations of two membrane potentials synchronized each other when the distance between the tubes was less than 10 mm. The synchronization was attended by the propagation of a potential pulse from one side to another with an interval of approximately 70 ms at a distance of 10 mm. It was examined whether the propagation of the potential pulse was due to electric conduction in bulk phases, or due to the interfacial conduction by several experiments in the addition of indifferent electrolytes or nonionic surfactant. Consequently, it has been demonstrated that the propagation of oscillation pulse was dominated mainly by the interfacial conduction process, and additionally by the bulk ionic conduction and that the interfacial diffusion and distribution of Cl(-) played a crucial role.

Ultrasonography findings and symptoms in acute rotavirus gastroenteritis.

BACKGROUND: The aim of the present study was to better understand how clinical events in acute rotavirus gastroenteritis are depicted on ultrasonography. METHODS: The relationship between abdominal ultrasonography and clinical course and symptoms was evaluated in 92 patients with acute rotavirus gastroenteritis (51 boys, 41 girls) with an average age of 30.7 ± 24.6 months. RESULTS: Significant correlations were observed between ultrasonography score and duration of illness after ultrasonography (P = 0.0232). It was also interesting that ultrasonography findings (score: 3.1 ± 1.0 vs 3.6 ± 1.2; P = 0.0118), clinical symptoms (3.1 ± 1.7 score vs 3.8 ± 1.8 score, P = 0.0293), and duration of illness after ultrasonography (4.4 ± 1.4 days vs 3.8 ± 1.1 days, P = 0.0301) were significantly different between patients examined on ultrasonography < 1 day after illness onset (n = 50, but duration of illness after ultrasonography followed only in 42) and those examined ≥ 2 days after onset (n = 42, but duration of illness after ultrasonography followed only in 35). CONCLUSION: The ability of abdominal ultrasonography to indicate severity of disease makes abdominal ultrasonography an important guide to therapy.

Conducting polymer-coated electrode as a reference/counter electrode in an organic phase and its application to a two-electrode type thin-layer cell for voltammetry at the liquid | liquid interface.

An indium tin oxide glass electrode coated with poly(3,4-ethylenedioxythiophene), PEDOT, PEDOT-ITOE, was proposed as an electrode workable as both a reference electrode and a counter one, a reference/counter electrode, in an organic phase and applied to a thin-layer cell of a two-electrode system for voltammetry at the liquid | liquid interface. By oxidizing the PEDOT film by 50% and doping a supporting electrolyte anion in an organic phase into the PEDOT film, a suitable depolarization was realized at the PEDOT | organic phase interface. The partially oxidized PEDOT-ITOE showed a Nerntian response to the supporting electrolyte anion concentration in the organic phase. The electrode potential was stable within +/-3 mV for 12 h, and showed a consistent value among the PEDOT-ITOEs prepared under the same procedure (the error range was about 7 mV, n = 8).

Histological findings in the livers of patients with neonatal intrahepatic cholestasis caused by citrin deficiency.

AIM: To characterize the histological features of the livers of patients with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), we studied specimens from 30 patients diagnosed with NICCD by genetically analyzing the SLC25A13 gene. METHODS: Liver biopsy specimens were subjected to hematoxylin-eosin, Azan, and Berlin-blue staining. RESULTS: Most specimens showed varying degrees of fibrosis. The degree of inflammation varied among the specimens, with half showing moderate or severe inflammatory changes. Fat deposition in hepatocytes was observed in almost all of the specimens, and severe fatty liver was noted in 20 (67%) of them. There was a mixture of two types of hepatocytes with macrovesicular or microvesicular fat droplets, and cholestasis was observed at a rate of 77%. Hemosiderin deposition, mostly mild and localized in periportal hepatocytes and macrophages in portal areas, was observed in 57% of the specimens. CONCLUSION: A combination of mixed macrovesicular and microvesicular fatty hepatocytes and the above-described findings, such as fatty liver, cholestasis, necroinflammatory reaction and iron deposition, are almost never observed in other liver diseases in infants and adults. We believe that NICCD is a disease with characteristic hepatopathological features.

Interfacial-specific chemiluminescence at Liqud/liquid interfaces or at O/W emulsions containing lucigenin in oil phase.

The enhanced effect of chemiluminescence (CL) of lucigenin (Luc(2+)) at a flat liquid/liquid interface and at O/W emulsions was demonstrated. The CL was emitted when Luc(2+) was transferred from an organic phase to an aqueous one containing NaOH and H(2)O(2). The CL intensity and emission spectrum depended strongly on the kind of organic solvent. We attempted to apply the CL reaction of Luc(2+) in the O/W emulsion system to the analysis of H(2)O(2). The available analytical conditions were discussed from the aspects of the kind of organic solvent, the reaction time and wavelength detected.

Estimation of optimal amount of fluoride dentifrice for adults to prevent caries by comparison between fluoride uptake into enamel in vitro and fluoride concentration in oral fluid in vivo.

Fluoride dentifrice has been accepted widely for use in caries prevention and its effectiveness has been confirmed. In order to enable the use of fluoride dentifrice effectively in daily brushing, the present study was performed to examine the relationship between fluoride uptake and the amount of fluoride dentifrice used and brushing time for adults. We examined the relationship between fluoride uptake into the surface layer (4-6 microm)of enamel and the active fluoride concentration in vitro and the relationship between the amount of fluoride dentifrice (1,000 ppmF) used and the fluoride concentration in oral fluid in vivo. It became clear that fluoride uptake into the enamel was increased at the concentrations of 300 ppmF or more. Fluoride uptake at 300 ppmF was increased for 2 min and became saturated thereafter. The results of the relationship between the fluoride concentration in the oral fluid and the amount of fluoride dentifrice used indicated that the amount of dentifrice that could maintain the mean fluoride concentration at 300 ppm or more for 2 min was 1.0 g or more. From these results, the recommended amount of fluoride dentifrice (1,000 ppmF) is 1.0 g or more for adults.

Extracorporeal leukocyte removal therapy for patients with ulcerative colitis.

BACKGROUND: The purpose of the present paper was to investigate efficacy of leukocytapheresis (LCAP) or granulocytapheresis (GCAP) in pediatric patients with ulcerative colitis (UC), including reduction of the total dose and side-effects of corticosteroids. METHODS: Courses of five Japanese adolescents with UC were analyzed. Four patients had recurrent UC with repeated remissions and exacerbations despite therapy including 5-aminosalicylic acid in combination with a corticosteroid. The other patient had a first attack. Effectiveness of adding LCAP or GCAP was assessed with regard to short-term changes in clinical activity, complications, and longer-term outcome. RESULTS: Clinical improvement was attained in three patients, while the other two did not improve and underwent colectomy. One of the two patients had moderately severe complications from LCAP and showed increased clinical activity during LCAP. The other, who began therapy with LCAP alone, had moderate improvement only after addition of a corticosteroid. CONCLUSION: Additional studies are needed to determine optimum timing of LCAP or GCAP and initiation of remission-maintenance therapy.

[A case of isolated CNS sarcoidosis with diffuse confluent high intensity lesions at bilateral deep white matter].

We reported a 60-year-old woman who suffered from isolated neurosarcodosis. She was presenting comprehensive dysfunction and intermittent high fever. In several months she gradually developed dysorientation, amnesia, dementia. However, no focal sign such as paralysis or sensory disturbance was demonstrated. Her blood chemistry showed normal including ACE (angiotensin converting enzyme) and lysozyme. Cerebrospinal fluid revealed elevated mononuclear cells, protein, and decreased glucose level. At first we treated with antibiotics including antiviral drugs in suspect of the infectious encephalomeningitis. But no improvement was observed. The elevation of ACE in spinal fluid made us suspect of neurosarcoidosis. So intravenous predonizoron (1,000 mg) was given, improving. Her high fever and mental disturbance improved. Second spinal fluid showed improvement. During the course her brain MRI revealed new bilateral diffuse confluent high intensity lesions at the deep white matters. Brain biopsy of deep matter at the right anterior lobe showed noncaseating granuloma. Since systemic work-up to detect sarcoidosis did not reveal lesions other than CNS, we considered this patient as having isolated CNS sarcoidosis.

Relationship between interfacial transfer and adsorption-desorption of surface-active bis-ammonium ions at a liquid/liquid interface.

Cyclic voltammograms and interfacial tension-applied potential curves were recorded at the interface between water containing surface-active bis-quaternary ammonium ions, bis-A(2+), and an organic solvent such as 1,2-dichloroethane or nitrobenzene. An ordinary diffusion-controlled voltammetric wave for the transfer of bis-A(2+) from aqueous phase to organic phase, the first wave, was followed by a typical adsorption-related wave, the second wave. It was found from the potential dependence of the interfacial tension of bis-A(2+) that the second wave was due to the desorption of bis-A(2+) toward the organic phase. The influence of the structure of bis-A(2+) on voltammograms was investigated, and the potential for the first wave was found to depend on both the length of the side chain and that of the spacer chain, whereas the potential for the second wave depended on the latter only. The thermodynamic relations among three processes of the ion transfer, adsorption, and desorption were discussed based on the experimental results.

Efficacy of interferon-alpha treatment in Japanese children with chronic hepatitis C.

BACKGROUND: We investigated the efficacy of natural interferon (IFN)-alpha treatment in 34 Japanese children with chronic hepatitis C. METHODS: Thirty-four children completed 6 months of therapy with natural IFN-alpha and were followed for 12 months or longer. We examined the serum hepatitis C virus (HCV) RNA titer and liver histology before, during, and after IFN treatment. RESULTS: At 6 months after the cessation of IFN-alpha treatment, 16 patients (47%) had normal serum alanine aminotransferase concentration and no detectable serum HCV RNA. There were no major side-effects, excluding some influenza-like symptoms during the IFN-alpha treatment. Most genotype 2a patients had a complete response (80%). Moreover, patients who had a low HCV RNA titer (<102 copies/mL) after 1 month of IFN-alpha treatment became complete responders at 6 months after the cessation of treatment. Histological improvement was observed in almost all patients after IFN-alpha treatment. CONCLUSION: Interferon-alpha treatment is safe and effective for children with chronic hepatitis C and has no serious side-effects. A HCV RNA concentration of <102 copies/mL after 1 month of IFN-alpha treatment and genotype 2a may be useful predictors of long-term IFN efficacy.