An approach to on-line electrospray mass spectrometric detection of polypeptide antibiotics of enramycin for high-speed counter-current chromatographic separation

In the field of pharmaceutical and biomedical analysis of peptides, a rapid on-line detection and identification for a methodology have been required for the discovery of new biological active products. In this study, a high-speed counter-current chromatography with electrospray mass spectrometry (HSCCC/ESI-MS) was developed for the on-line detection and purification of polypeptide antibiotics of enramycin-A and -B. The analytes were purified on HSCCC model CCC-1000 (multi-layer coil planet centrifuge) with a volatile solvent of two-phase system composed of n-butanol/hexane/0.05% aqueous trifluoroacetic acid solution (43/7/50, V/V/V), and detected on an LCMS-2010EV quadrupole mass spectrometer fitted with an ESI source system in positive ionization following scan mode (m/z 100-2000). The HSCCC/ESI-MS peaks indicated that enramycin-A (major m/z 786 [M+3H](3+) and minor m/z 1179 [M+2H](2+)) and enramycin-B (major m/z 791 [M+3H](3+) and minor m/z 1185 [M+2H](2+)) have the peak resolution value of 2.9 from 15mg of loaded enramycin powder. The HSCCC collected amounts of the peak fractions were additionally 4.3mg (enramycin-A), and 5.9mg (enramycin-B), respectively. These purified substances were analyzed by LC/ESI-MS with scan positive mode. Based on the LC/ESI-MS chromatograms and spectra of the fractions, enramycin-A and -B were estimated to be over 95% purity. The overall results indicate that this approach of HSCCC/ESI-MS is a powerful technique for the purification and identification of bioactive peptides.

Purification of curcumin, demethoxycurcumin, and bisdemethoxycurcumin by high-speed countercurrent chromatography

Curcuminoids are substances of great interest because of their important pharmacological activities, particularly anti-inflammatory, anticarcinogenic, and anti-Alzheimer's activities. In this study, we report the first procedure and effect of processing for the high, efficient, and useful purification of curcumin, demethoxycurcumin, and bisdemethoxycurcumin from turmeric powder. Purification involves high-speed countercurrent chromatographic (HSCCC) separation of these curcuminoids using a simple two-phase solvent system composed of n-hexane/chloroform/methanol/water (5/10/7.5/2.5, v/v). The HSCCC-fractionated effluent peaks indicated that the peak resolutions were 1.7 between curcumin and demethoxycurcumin and 2.1 between demethoxycurcumin and bisdemethoxycurcumin for 25 mg of loaded turmeric powder. These purified substances were analyzed by liquid chromatography-tandem mass spectrometry with scan and daughter scan negative modes, and the wide absorbance from 200 to 500 nm was monitored by photodiode array detection. The separation yielded 1.1 mg of curcumin, 0.6 mg of demethoxycurcumin, and 0.9 mg of bisdemethoxycurcumin (>98% purity). Moreover, the antioxidant effect of curcuminoids was measured by a 1,1-diphenyl-2-picrylhydrazil assay. The order of antioxidant activity was purified curcumin > purified demethoxycurcumin > purified bisdemethoxycurcumin > turmeric powder. Curcumin, demethoxycurcumin, and bisdemethoxycurcumin can be used for various evaluations of their pharmacological activities.

Determination of nucleotides in infant formula by ion-exchange liquid chromatography

Nucleotide-supplemented infant formula has been shown to positively modify the composition of intestinal microflora, emulating the attribute of human milk. Quantification of nucleotides in infant formula is of interest because of its applicability in quality and safety assessments. There is no standard method for the analysis of nucleotides in infant formula. In the present study, ion-exchange liquid chromatography (IELC)- and centrifugal ultrafiltration (CUF)-based protocols were developed for routine determination of additive nucleotides in infant formula. Five target nucleotides, guanosine 5'-monophosphate (GMP), inosine 5'-monophosphate (IMP), uridine 5'-monophosphate (UMP), cytidine 5'-monophosphate (CMP), and adenosine 5'-monophosphate (AMP) were measured by IELC with a mobile phase of 50 mM diammonium hydrogen phosphate buffer, pH 4.0, with UV detection at 254 nm. The calibration was linear over the range 0.5-50 microg/mL; R(2) = 0.999. The calculated LOD and LOQ were 0.01-0.05 microg/mL and 0.05-0.5 microg/mL, respectively. Recovery values (spiked concentration levels: 0.5, 5, and 10 microg/mL) ranged from 85.0 +/- 1.4% to 92.3 +/- 2.1% using only CUF preparation. This was applied to measure the concentration of five nucleotides in common infant formulas.

Purification and gene sequencing of conjugated linoleic acid reductase from a gastrointestinal bacterium, Butyrivibrio fibrisolvens

AIMS

To characterize the cause for the lack of conjugated linoleic acid (CLA) reductase (CLA-R) activity in the Butyrivibrio fibrisolvens MDT-5 strain that rapidly isomerizes linoleic acid (LA) to CLA without hydrogenation, the CLA-R was purified and its gene (cla-r) sequence was determined.

METHODS AND RESULTS

CLA-R was purified to near homogeneity as a 53-kDa monomeric protein from the high CLA-R activity-expressing strain MDT-10. The purified CLA-R recognized conjugated double bonds. Unsaturated fatty acids containing 18 carbons markedly increased the CLA-R expression at the transcriptional level. Complete sequencing of the cla-r gene revealed that the CLA-R is a novel protein. Sequence analysis of the cla-r gene from the MDT-5 strain revealed that the MDT-5 CLA-R protein sequence differed from that of the MDT-10 at four consecutive amino acids. Northern and Western blotting analyses confirmed that the cla-r mRNA and protein are expressed normally in MDT-5.

CONCLUSIONS

Strain MDT-5 expresses the CLA-R protein that lacks enzyme activity because of mutation, which explains why MDT-5 exclusively produces CLA from LA.

SIGNIFICANCE AND IMPACT OF THE STUDY

The cla-r gene was sequenced for the first time. Exogenous fatty acids affected the cla-r transcription. These results will provide additional knowledge on biohydrogenation, and may also augment the CLA production in the gastrointestinal tract.

Isolation of a novel strain of Butyrivibrio fibrisolvens that isomerizes linoleic acid to conjugated linoleic acid without hydrogenation, and its utilization as a probiotic for animals

AIM

Isolation of a new strain of Butyrivibrio fibrisolvens possessing great capacity to produce conjugated linoleic acid (CLA) in order to utilize as a probiotic for animals.

METHODS AND RESULTS

A novel strain (MDT-5) was isolated from the goat rumen, which exclusively converted linoleic acid (LA) to CLA, because of its high LA isomerase activity with virtually no CLA reductase activity. MDT-5 also converted linolenic acid to conjugated linolenic acid that may be more bioactive than CLA. The oral administration of MDT-5 every other day to mice for 2 weeks resulted in increased amounts of CLA in the contents of the large intestine (2.5-fold), as well as in adipose tissue (threefold). Feeding a high-LA diet, as well as prolonging the period of MDT-5 administration, further increased the CLA content in body fat.

CONCLUSIONS

MDT-5 has by far greater ability to produce CLA than any other known bacteria. Administration of MDT-5 to mice increases CLA production in the large intestine, which results in increased CLA absorption.

SIGNIFICANCE AND IMPACT OF THE STUDY

MDT-5 may be useful in pet animals as a probiotic to provide CLA continuously.

Augmentation of vaccenate production and suppression of vaccenate biohydrogenation in cultures of mixed ruminal microbes

To increase ruminal outflow of trans-vaccenic acid (t-VA), a new strain of Butyrivibrio fibrisolvens (MDT-10) was isolated that has a great ability to hydrogenate linoleic acid (LA) to t-VA. When strain MDT-10 was added to the batch cultures of mixed ruminal microbes (1% of the total number of viable ruminal bacteria), LA conversion to t-VA increased greatly; after 3 h, t-VA levels were > 4-fold higher than the control. By 10 h, all of the t-VA was hydrogenated to stearic acid. However, when a new strain of Bifidobacterium adolescentis (HF-11), which has a high capacity for incorporation of t-VA, was added in conjunction with MDT-10 (1% of the total number of ruminal bacteria), t-VA levels after 10 h were 6 times higher than with MDT-10 alone. These results suggest that t-VA produced by MDT-10 was incorporated into HF-11 cells, resulting in protection of t-VA from t-VA-hydrogenating microbes. Similar results were obtained in a continuous culture of mixed ruminal microbes in which addition of HF-11 simultaneously with MDT-10 increased the amount of t-VA in the effluent 2.5-fold. Both MDT-10 and HF-11 appeared to grow readily in the presence of mixed ruminal microbes. Sixty-two percent of t-VA incorporated by HF-11 was present in the free form, whereas 19, 15, and 3%, respectively, were incorporated into monoacylglycerol, glycerophospholipid, and diacylglycerol fractions. Because these lipids can be digested in the small intestine, it is likely that most t-VA in HF-11 cells is absorbed. Thus, introduction of MDT-10 and HF-11 simultaneously to the rumen might increase the amount of t-VA absorbed and might consequently increase the conversion of t-VA to conjugated linoleic acid in tissue.

The acidic complexation of tetracycline with sucralfate for its mucoadhesive preparation

The complex of antibiotics with sucralfate (SF) was prepared with acid. The mechanism of the complexation and some factors concerning the preparation, which influence the mucoadhering property, were studied. The complexation was confirmed by the change in color and instrumental analysis. The acidic complex appeared to be produced by reagglomeration of SF preliminary particles. It was suggested that the amide or amine groups of tetracycline (TC) and aluminum moieties of SF serve as the binding sites. The potential of multiple binding sites and a priority in them were suggested by the Scatchard plot analysis. The additional amounts of acid and the increase in the surface area increased the number of sites. The amount of the additional acid appeared to be the most important factor during the preparation of the acidic complex. The appropriate amount of acid added appeared to produce a complex rich in TC. However, an excess amount might cause the excess dissociation of aluminum moieties, which destroys the mucoadhesive paste-forming property.

A Novel Evaluation Method of Gastric Mucoadhesive Property in Vitro and the Mucoadhesive Mechanism of Tetracycline-Sucralfate Acidic Complex for Eradication of Helicobacter pylori

PURPOSE

The gastric mucoadhesive property of tetracycline-sucralfate acidic complex (CO) was evaluated by using a novel method in vitro to compare with the in vivo test. The mucoadhesive mechanism of the acidic complex was also studied.

METHODS

The gastric mucosa removed from a rat was placed covering the end of a plunger and secured in a disposable syringe. The acidic test medium was gradually infused in and then flowed out. Two different kinds of CO, tetracycline, or a physical mixture (PM) were introduced into the device to compare their mucoadhesive properties. The tetracycline content in the residue on the mucosa was measured. The results were compared with those of the in vivo test. The acidic response of CO and the protein binding capacity of a sucrose octasulfate group (SOS) in sucralfate or CO were evaluated.

RESULTS

The mucoadhesive properties of CO were clearly superior to those of PM. The remaining amounts of tetracycline in each test sample, determined by the in vitro test, were in agreement with those of the in vivo test. The excellent mucoadhesive property of CO appeared to be caused by the rapid response to the acid and resulting mucoadhesive gel formation. Furthermore, the binding capacity of SOS to the protein was clearly greater than that of PM. The excessive acid treatment during the preparation of CO tended to decrease the mucoadhesive property.

CONCLUSIONS

CO appeared to be potentially useful for the eradication of Helicobacter pylori because of the direct delivery of tetracycline to the gastric mucosa for an extended period of time.

Change in secondary structure of silk fibroin during preparation of its microspheres by spray-drying and exposure to humid atmosphere

Silk microspheres prepared by spray-drying were exposed to humid atmosphere (89% relative humidity, RH). Change in the secondary structure of silk fibroin during preparation of silk microspheres and exposure to high humidity was studied. Scoured silk fiber was dissolved in an aqueous solution of calcium chloride mixed with ethanol. After dialysis against purified water, theophylline was added to the solution as a model drug. Silk microspheres were obtained by spray-drying. Silk fibroin and theophylline were found to be amorphous in the microsphere by means of powder X-ray diffractometry. Fibroin assumed a beta-sheet conformation in the scoured silk fiber while it has an irregular structure in the microsphere, according to FTIR and Raman spectra. Fibroin recrystallized and its secondary structure changed to beta-sheet conformation by exposure of the microspheres to an atmosphere of 89% RH.

Thermal gelation of aqueous curdlan suspension: preparation of curdlan jelly

Curdlan jelly was prepared by heating an aqueous curdlan suspension at 70 degrees C for 5 min. Theophylline, as a model drug, was entrapped in the jelly network. Curdlan jelly had a hardness comparable with that of commercially available jelly for confectionary. Syneresis was observed for 8 days after the preparation and was not detected during the experimental term from the gel prepared from 10% w/v curdlan suspension. Release of theophylline from the jellies was sustained, and was increasingly delayed with an increase in the curdlan concentration. An aqueous curdlan suspension was studied by means of differential scanning calorimetry (DSC) up to 80 degrees C and down to -25 degrees C, and subsequent re-heating to 30 degrees C. Enthalpy increased with the concentration of curdlan, while the temperature at the onset of the endothermic peak decreased with the concentration of curdlan. The enthalpy due to thermal gelation of 1 mg curdlan was 12.2 mJ. An increase in curdlan concentration decreased the enthalpy and lowered the onset temperature of the endothermic peak during the DSC re-heating scan. The results are due to an increase in the amount of non-freezing water and freezing bound water and a decrease in free water. The number of water molecules entrapped in the curdlan jelly as non-freezing water was 8.1 per glucopyranose residue.

Nerve growth factor and substance P are useful plasma markers of disease activity in atopic dermatitis

BACKGROUND

Neurogenic components, such as neurotrophic factors and neuropeptides, are probably involved in the pathogenesis of atopic dermatitis (AD) via the neuroimmunocutaneous system. Numerous in vitro and in vivo studies have shown that nerve growth factor (NGF), the best-characterized member of the neurotrophin family, modulates the synthesis of the neuropeptide substance P (SP), both of which may be associated with the pathogenesis of human allergic diseases.

OBJECTIVES

To evaluate the levels of NGF and SP in the plasma of patients with AD and to examine their possible correlation with disease activity.

METHODS

We measured plasma levels of NGF by an immunoenzymatic assay and of SP by aradioimmunoassay in 52 patients with AD, and compared them with 35 normal non-atopic controls. The severity of the disease in AD patients was evaluated using validated clinical scoring systems.

RESULTS

Patients with AD had significant increases in plasma levels of NGF and SP compared with controls (P < 0.0005 and P < 0.0001, respectively). A positive correlation between the plasma levels of NGF and SP was found in AD patients (correlation coefficient, Cc = 0.920, P < 0.0001). There was a significant correlation of plasma NGF and SP levels with disease activity evaluated using three different scoring systems: the grading system of Rajka and Langeland (P < 0.001 and P < 0.01, respectively), the objective Severity Scoring of AD (Cc = 0.656, P < 0.005 and Cc = 0.752, P < 0.0005, respectively) and the Eczema Area and Severity Index (Cc = 0.740, P < 0.001 and Cc = 0.765, P < 0.005, respectively).

CONCLUSIONS

These data represent the first reported evidence of increased plasma levels of NGF and SP in an allergic human skin disease. They suggest that these neurogenic factors systemically modulate the allergic response in AD, probably through interactions with cells of the immune-inflammatory component. In addition, NGF and SP may be useful markers of disease activity in patients with AD.

Expression of glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase in a case of pulmonary epithelioid haemangioendothelioma

This report describes a case of pulmonary epithelioid haemangioendothelioma in which the tumour cells expressed the glucocorticoid receptor and 11beta-hydroxysteroid dehydrogenase. The patient, a 15 year old girl, who had no other complaints or past illnesses, was found to have an abnormal shadow on a chest roentgenogram obtained at a school medical examination. Multiple nodular shadows in the bilateral lungs were also confirmed by computerised axial tomography scan. A diagnosis of pulmonary epithelioid haemangioendothelioma was made on the basis of lung biopsy specimens. The tumour cells were immunohistochemically positive for factor VIII related antigen, CD31, and CD34, but not surfactant apoprotein A. In addition, almost all of the tumour cells showed simultaneous expression of the glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase, suggesting that steroid treatment would be effective.

Effect of nicotinamide on the properties of aqueous HPMC solutions

The effect of nicotinamide on the properties of aqueous hydroxypropylmethylcellulose (HPMC) solutions was studied. Rheological studies showed that solutions of HPMC of concentration less than 3.0 w/v.% did not form gels and exhibited Newtonian flow patterns at 25 degrees C. The inclusion of nicotinamide increased the viscosity of HPMC solutions, which indicates that nicotinamide expanded the HPMC coils in aqueous solution. When the temperature of the solutions was raised, they formed gels that were detected by viscometry and oscillation tests as abrupt increases in viscosity, storage modulus and loss modulus and an abrupt decrease in loss angle. Nicotinamide exhibited a salting in effect on the HPMC solutions resulting in an increase in gelation temperatures and cloud points. These effects are considered to be due to the hydrogen-bonding of nicotinamide to HPMC molecules, which was suggested by a shift to a longer wavelength of the UV spectra of aqueous nicotinamide solutions by the addition of HPMC. These results suggested that nicotinamide has affinity with the hydrophilic groups of HPMC.

Transcription-mediated amplification is more useful in the follow-up of patients with chronic hepatitis B treated with lamivudine

Changes in the HBV DNA level during the treatment of patients with chronic hepatitis B with lamivudine were investigated by the transcription-mediated amplification (TMA) assay. Twenty-four patients treated with lamivudine (males:female= 20:4, age: 44.0+/-9.0 years, chronic hepatitis: 14, cirrhosis: 7, cirrhosis with hepatocellular carcinoma: 3) were investigated. The dosage of lamivudine was 75 mg/day in 3, 100 mg/day in 8, and 150 mg/day in 13 patients, and the administration period was 48+/-16 weeks (24-79 weeks). Sixteen patients were HBe antigen-positive before treatment, and the HBV DNA level was 7.4+/-1.2 (4.0- more than 8.7) LGE/ml. The HBV DNA level was measured every 1-6 months by the TMA assay and the branched DNA signal amplification technology (b-DNA assay). Serum HBV DNA disappeared in all patients by the b-DNA during the treatment period, while six patients had persistent HBV DNA by the TMA. The time of HBV DNA disappearance by the TMA in 18 patients was 2-5 months after initiation of treatment. The disappearance rate of HBV DNA was 3/8 (38%) in patients whose HBV DNA level before treatment was 8.0 LGE/ml or higher, 7/8 (88%) in those with 7-7.9 LGE/ml, and 8/8 (100%) in those with 6.9 LGE/ml or lower, showing that disappearance of HBV DNA became difficult when the HBV DNA level before treatment was high (P<0.01). In six patients, the HBV DNA level disappeared once, then increased thereafter. The present findings suggested that these increases in the HBV DNA level were due to an increase of YMDD mutant in three of these six patients, and due to a decrease in the dosage in two patients. In treatment with lamivudine, the TMA assay is more useful for understanding the changes in the HBV DNA level than b-DNA assay.

Effect of multiple subpial transection on motor cortical excitability in cortical dysgenesis

We report here a 12-year-old patient with unilateral cortical dysgenesis and intractable simple partial seizure in his left arm, who underwent multiple subpial transection (MST) in the right cerebral cortex including the primary motor cortex. We investigated motor cortical excitability using multimodal transcranial magnetic stimulation (TMS) before and 1 month after MST, in which surgical cortical incisions were made with strokes 5 mm apart and 4 mm deep. Preoperative TMS studies showed hyperexcitability in the affected motor cortex as abnormally prolonged muscle responses to TMS with a wide cortical motor map, which were markedly reduced following the operation. The preoperative motor evoked potentials were large and polyphasic, and consisted of early and late components. The late component was completely abolished after MST, suggesting that this component might be due to activation of the corticospinal tract neurones by long recurrent axon branches of dysplastic excitatory pyramidal neurones, which were cut by MST, or by delayed, polysynaptic intracortical conduction with marked temporal dispersion. Intracortical inhibition in the affected motor cortex was also disrupted preoperatively and improved after MST. Postoperative recruitment order of muscle responses to TMS was bilaterally symmetrical, indicating that MST did not interfere with the function of the corticospinal tract neurones. The patient showed fair motor recovery and good seizure control after the operation. These results of TMS studies demonstrated the remarkable effectiveness of MST not only on intractable seizure but also on abnormal motor cortical organization and hyperexcitability in cortical dysgenesis.

Clinical periodontal findings and microflora profiles in children with chronic neutropenia under supervised oral hygiene

BACKGROUND

This is the first known case report that used a polymerase chain reaction (PCR)-based method to help identify the oral microflora in patients with chronic neutropenia. In this study, we report clinical periodontal findings and microflora profiles of 2 children, 1 with severe congenital neutropenia (SCN, Kostmann type) and 1 with cyclic neutropenia (CN).

METHODS

The SCN patient had severe gingivitis, whereas the patient with CN had mild gingivitis in the gingival margins. Monthly oral cleaning instruction and review were performed without subsequent periodontal therapy. Oral hygiene conditions remained satisfactory and visible plaque was scarce, despite the persistence of mild gingivitis. Under supervised oral hygiene, we examined the presence of periodontal pathogens from patient plaque samples.

RESULTS

By a PCR-based method, Prevotella nigrescens, Bacteroides forsythus, Campylobacter rectus, and Capnocytophaga gingivalis were detected in the SCN patient and P. intermedia, C. rectus, C. gingivalis, and C. sputigena in the CN patient, suggesting the existence of periodontal pathogens. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, and C. ochracea were not found in either patient.

CONCLUSIONS

Use of 1% povidone iodine solution and local antibiotic application under supervised oral hygiene were helpful to improve gingival conditions in patients with chronic neutropenia.

Characterization of the hydroxypropylmethylcellulose-nicotinamide binary system

The effect of hydroxypropylmethylcellulose (HPMC) on the thermal behaviour of nicotinamide was studied. Binary mixtures of nicotinamide and HPMC, composed of various weight fractions of HPMC (X(HPMC)), were heated, cooled and subsequently re-heated. HPMC dissolved in fused nicotinamide at 140 degrees C. The binary mixture at compositions 0<==X(HPMC)<==0.3 formed a film structure on cooling. At X(HPMC)>==0.4, the molten nicotinamide at 140 degrees C was saturated with HPMC. These heated mixtures did not form a homogeneous film by cooling to ambient temperature. At X(HPMC)<0.4, differential scanning calorimetry peaks originating from recrystallization and melting of nicotinamide were observed in the cooling and re-heating scans, respectively. These peaks became smaller with increase in X(HPMC) and disappeared at X(HPMC) approximately 0.4. Decrease in crystallinity with increase in X(HPMC) was confirmed by X-ray diffraction. The glass transition temperature of the cooled mixture (T(g)) increased with increase in X(HPMC). When the enthalpy of melting of nicotinamide and 1/T(g) were plotted against X(HPMC), inflections were observed at similar X(HPMC) values, 0.37-0.38. Dissolution of HPMC in molten nicotinamide was accompanied by hydrogen bond formation, which was confirmed by infrared studies.

Formulation design of ointment base suitable for healing of lesions in treatment of bedsores

We intended to develop a desired ointment base suitable for treatment of bedsores including the proliferation of granulation and epidermis. The main bedsore bacteria detected in our hospital were S. aureus in gram-positive coccus and P. aeruginosa in gram-negative bacillus. As the macrogol ointment (MO) was found to have bactericidal effects on these bacteria, MO was adopted as the base for the objective ointment. To improve the properties of the ointment base such as regulating the humidity of the exudation and controlling the release of antibiotics formulated in the ointment, co-formulating effects of various additives to MO were evaluated. The sustained release function of the ointment base was obtained by adding hydrophilic petrolatum (HP) to MO. However, the resultant ointment was found to have a poor humidity regulating property. On the other hand, MO containing 5% of hydroxypropyl cellulose (HPC) showed both the humidity regulating and the controlled drug releasing properties. It was considered that HPC particles dispersed in the ointment could be swelled by absorbing water to form a gel network. The curd tension meter tests for the ointments prepared with the various polymers showed that the MO-HPC base, which showed the highest sustained drug releasing property, was found to have the highest hardness. This result means that HPC formulated into the base forms the most rigid gel structure to resist the erosion of the ointment and to control the drug release.

Regulation of H(+)-ATPase synthesis in response to reduced pH in ruminal bacteria

The capacity of ruminal bacteria to regulate H(+)-ATPase synthesis in response to reduced pH was investigated to explain acid tolerance. The activity of H(+)-ATPase in Streptococcus bovis, an acid-tolerant bacterium, was 2.2-fold higher at pH 4.5 than at pH 5.5. The increase in the amount of H(+)-ATPase protein was similar, suggesting that the increase in H(+)-ATPase activity is owing to the increase in H(+)-ATPase synthesis. The level of atp-mRNA at pH 4.5 was 2.5-fold higher than at pH 5.5, indicating that H(+)-ATPase synthesis is regulated at the transcriptional level, responding to low pH. In Ruminococcus albus, an acid-sensitive bacterium, H(+)-ATPase activity, the amount of H(+)-ATPase protein, and the level of atp-mRNA at pH 7.0 were similar to the values at pH 6.0, the lowest pH permitting growth. This result suggests that R. albus is incapable of enhancing H(+)-ATPase synthesis at low pH. Thus, acid tolerance appeared to be related to the capacity to augment the synthesis of H(+)-ATPase responding to low pH.

Improvement of encapsulation efficiency of water-in-oil-in-water emulsion with hypertonic inner aqueous phase

Water-in-oil-in-water (w/o/w) emulsions encapsulating tryptophan or theophylline were prepared where these compounds are regarded as model drugs. The effects of sodium chloride on the drug entrapment into the w/o/w emulsions and on the separation of aqueous phases were studied. The degree of encapsulation of tryptophan in the w/o/w emulsion increased with the concentration of sodium chloride added in the inner aqueous phase, while it decreased with that in the outer aqueous phase. As for theophylline, although the degree increased with a concentration of sodium chloride in the inner phase, the effect was smaller than that on tryptophan. The difference in the effects between on tryptophan and on theophylline was attributed to their partition coefficients. Theophylline was easily leaked out from the inner phase to the outer aqueous phase after its dissolution and diffusion in the oil phase due to a higher partition coefficient. More than 55% of the aqueous phase was separated from the w/o/w emulsion within 24 h, when sodium chloride was not added in the inner aqueous phase. However, the separation was not observed when more than 0.2M sodium chloride was added. To the contrary, sodium chloride added in the outer aqueous phase accelerated the separation. It was, therefore, concluded that sodium chloride in the inner aqueous phase plays an important role in suppression of the separation and in encapsulation of the drug which does not penetrate into the oil membrane.

Basic study for stabilization of w/o/w emulsion and its application to transcatheter arterial embolization therapy

Stabilization of w/o/w emulsion and its application to transcatheter arterial embolization (TAE) therapy are reviewed. W/o/w emulsion was stabilized by making inner aqueous phase hypertonic, addition of chitosan in inner phase, and techniques of phase-inversion with porous membrane. Lipiodol w/o/w emulsion for TAE therapy was prepared by using a two-step pumping emulsification procedure. The procedure is so easy that the emulsion could be prepared even during the surgical operation. The deposition after hepatic arterial administration of the emulsion was detected by an X-ray CT scanner. The concentration of epirubicin hydrochloride (EPI) in liver was increased and its residence was prolonged by encapsulating it in the w/o/w emulsion. The toxic effects of EPI and lipiodol on the normal hepatic cells were reduced. The w/o/w emulsion prepared by us is a suitable formulation for the TAE therapy.