High-performance liquid chromatographic determination of ribavirin in whole blood to assess disposition in erythrocytes

Ribavirin is an antiviral agent used in the treatment of chronic hepatitis C virus infection. One of the limitations associated with the use of ribavirin is a reversible anemia caused by its accumulation in erythrocytes. Therefore, it is of interest to determine ribavirin levels in erythrocytes, as well as in plasma, as these measurements may be predictive of hematotoxicity. In the present study, we describe a high-performance liquid chromatographic (HPLC) assay for ribavirin in whole blood to estimate concentrations of free ribavirin and phosphorylated anabolites in erythrocytes. Since ribavirin exists primarily as phosphorylated anabolites (mono-, di-, and triphosphates) in erythrocytes, whole-blood extracts were initially dephosphorylated with acid phosphatase. The enzyme-treated samples were subjected to phenyl boronic acid column extraction for cleanup. The purified fraction was analyzed by reversed-phase HPLC, which was optimized for determination of ribavirin levels in whole blood. The recoveries of ribavirin from whole blood ranged from 63.1 to 90.7% at concentrations ranging from 1.67 to 40.0 microM. Intra- and interassay variations estimated at these concentrations were 3.2 to 10.4 and 4.7 to 11.7%, respectively. This method was used to quantitate ribavirin in samples both treated and untreated with acid phosphatase to estimate the extent of intracellular phosphorylation in erythrocytes. The method was also used to evaluate the effects of dipyridamole, a nucleoside transporter inhibitor, on ribavirin disposition in erythrocytes in in vitro experiments.

Hypoglycemic coma masquerading thyrotoxic storm

A 59-year-old woman was hospitalized in hypoglycemic coma. Although hypoglycemia was promptly reversed, she was in a somnolent, restless state with tachycardia, tremor, profuse sweating, and high body temperature. Thyrotoxic storm was highly suspected and vigorous antithyroid regimens gradually brought her up to normal mental and cardiovascular states in several days. However, profound generalized myopathy necessitated the maintenance with a respirator. One month later, an episode of angina pectoris was followed by generalized convulsion, coma, and death in a few days. Neuroimaging study disclosed posterior leukoencephalopathy syndrome. This case is instructive in that hypoglycemic coma may masquerade the major symptomatology of thyrotoxic storm, and that profound myopathy and angiopathic or angiospastic processes of the brain and the heart may interfere with the outcome.

Hybrid motor with H(+)- and Na(+)-driven components can rotate Vibrio polar flagella by using sodium ions

The bacterial flagellar motor is a molecular machine that converts ion flux across the membrane into flagellar rotation. The coupling ion is either a proton or a sodium ion. The polar flagellar motor of the marine bacterium Vibrio alginolyticus is driven by sodium ions, and the four protein components, PomA, PomB, MotX, and MotY, are essential for motor function. Among them, PomA and PomB are similar to MotA and MotB of the proton-driven motors, respectively. PomA shows greatest similarity to MotA of the photosynthetic bacterium Rhodobacter sphaeroides. MotA is composed of 253 amino acids, the same length as PomA, and 40% of its residues are identical to those of PomA. R. sphaeroides MotB has high similarity only to the transmembrane region of PomB. To examine whether the R. sphaeroides motor genes can function in place of the pomA and pomB genes of V. alginolyticus, we constructed plasmids including both motA and motB or motA alone and transformed them into missense and null pomA-paralyzed mutants of V. alginolyticus. The transformants from both strains showed restored motility, although the swimming speeds were low. On the other hand, pomB mutants were not restored to motility by any plasmid containing motA and/or motB. Next, we tested which ions (proton or sodium) coupled to the hybrid motor function. The motor did not work in sodium-free buffer and was inhibited by phenamil and amiloride, sodium motor-specific inhibitors, but not by a protonophore. Thus, we conclude that the proton motor component, MotA, of R. sphaeroides can generate torque by coupling with the sodium ion flux in place of PomA of V. alginolyticus.

Glycyrrhetinic acid-induced apoptosis in thymocytes: impact of 11beta-hydroxysteroid dehydrogenase inhibition

It has been proposed that glycyrrhetinic acid (GA) enhances endogenous glucocorticoid (GC) action by suppressing the metabolism of the steroid. We show here that marked involution of the thymus occurred within 24 h of a single intraperitoneal administration of GA in mice. Thymocytes from mice treated with GA exhibited DNA cleavage and mitochondrial transmembrane potential disruption, as demonstrated with agarose gel electrophoresis and flow cytometric analysis. Immunocytochemical staining revealed that CD4(+)CD8(+) double positive cells markedly decreased after GA treatment. In contrast to GA in vivo, GA in vitro did not induce apoptosis of cultured thymocytes. These findings suggest that the apoptosis-inducing effect of GA on thymocytes is due to its indirect action. Because GA has been known to inhibit 11beta-hydroxysteroid dehydrogenase (11beta-HSD), we measured the enzyme activity in major organs and endogenous corticosterone concentration after GA treatment. The results showed a significant decrease of 11beta-HSD activity (P < 0.0001) and an increase in serum corticosterone concentration (P < 0.005). We concluded that the inhibition of hepatic 11beta-HSD activity by GA has a serious effect on GC metabolism, which results in a significant elevation of systemic GC levels. Apoptosis of thymocytes occurred as a consequence of the elevation in the level of endogenous corticosterone.

Monoamine oxidase inhibitory naphthoquinone and/or naphthalene dimers from Lemuni Hitam (Diospyros sp.), a Malaysian herbal medicine

From the extract of a Malaysian herbal medicine, Lemuni Hitam (Diospyros sp.), which exhibited monoamine oxidase (MAO) inhibition, three new naphthoquinone and/or naphthalene dimers (lemuninols A-C, 1-3) were isolated together with 4,6-dihydroxy-5-methoxy-2-methyl-naphthalene (8) and six known monomers (4-7, 9 and 10). The structures were determined by spectroscopic methods including 2D-NMR techniques. Among them, lemuninol A showed 45% inhibition of MAO (mouse liver) at 5.0 x 10(-6) g/ml, and lemuninols B and C and a naphthoquinone (9) indicated weak activity. Some related quinones were also tested for their MAO inhibitory activities.

Functional interaction between PomA and PomB, the Na(+)-driven flagellar motor components of Vibrio alginolyticus

Four proteins, PomA, PomB, MotX, and MotY, appear to be involved in force generation of the sodium-driven polar flagella of Vibrio alginolyticus. Among these, PomA and PomB seem to be associated and to form a sodium channel. By using antipeptide antibodies against PomA or PomB, we carried out immunoprecipitation to verify whether these proteins form a complex and examined the in vivo stabilities of PomA and PomB. As a result, we could demonstrate that PomA and PomB functionally interact with each other.

[The role of virulence factor of elastolytic proteinase from Aspergillus fumigatus]

The role of virulence factor of elastolytic proteinase produced by Aspergillus fumigatus was investigated in mice immunocompromised with cyclophosphamide (CY) to block neutrophil and lymphocyte functions or with carrageenan (CA) to block the phagocytic activity of macrophages. These mice were infected through inhalation with the spores of elastolytic proteinase producing or nonproducing strains of A. fumigatus, and then were observed daily for 15 days or until death. Compared to CY-immunocompromised mice treated with the spores of proteinase nonproducing strains, CY-immunocompromised mice treated with the spores of proteinase producing strains had a significantly shorter survival rate. Furthermore, when treated with the spores of proteinase producing strains, CA-immunocompromised mice survived significantly longer than did CY-immunocompromised mice. Assessment of the effect of elastolytic proteinase on rat lung showed that this enzyme induced hemorrhage of the lung, alveolar septal edema and alveolar hypertrophy due to blood neutrophil infiltration. Neither fusion nor denaturation of the elastic fiber was observed, however. These studies have suggested that when infected with A. fumigatus, a severe lesion in bronchioli or alveoli is induced by the proteinase producing strains, and that these strains are more virulent than the proteinase nonproducing strains.

Conversion of a bacterial warm sensor to a cold sensor by methylation of a single residue in the presence of an attractant

The aspartate chemoreceptor (Tar) of Escherichia coli also serves as a thermosensor, and it is very amenable to genetic and biochemical analysis of the thermosensing mechanism. Its thermosensing properties are controlled by reversible methylation of the cytoplasmic signalling/adaptation domain of the protein. The unmethylated and the fully methylated (aspartate-bound) receptors sense, as attractant stimuli, increases (warm sensor) and decreases (cold sensor) in temperature respectively. To learn more about the mechanism of thermosensing, we replaced the four methyl-accepting glutamyl residues with non-methylatable aspartyl residues in all possible combinations. In a strain defective in both methyltransferase (CheR) and methylesterase (CheB) activities, all of the mutant Tar proteins functioned as warm sensors. To create a situation in which all of the remaining glutamyl residues were methylated, we expressed the mutant proteins in a CheB-defective, CheR-overproducing strain. The fully glutamyl-methylated proteins were designed to mimic the full range of methylation states possible for wild-type Tar. Almost all of the methylated mutant receptors, including those with single glutamyl residues, were cold sensors in the presence of aspartate. Thus, binding of aspartate to Tar and methylation of its single glutamyl residue can invert its temperature-dependent signalling properties.

Suppression by the DNA fragment of the motX promoter region on long flagellar mutants of Vibrio alginolyticus

The axial length of the polar flagellum (Pof) of Vibrio alginolyticus is about 5 microm. We previously isolated mutants that make abnormally long flagella. The swarm sizes of these mutants in a soft agar plate are smaller than that of a wild-type strain. We cloned a DNA fragment into the pMF209 plasmid that restored the swarming ability of the long-Pof strain V10578. The swimming speed and flagellar length of these transformants were almost equal to the wild-type values. The amounts of PF47 flagellin and PF60 sheath-associated protein, which increased in the long-Pof mutants, were retrieved to almost the wild-type level in the transformants. The plasmid pMF209 contained only a 143 bp chromosomal fragment whose sequence is about 80% similar to that of the motX promoter region of V parahaemolyticus. We speculate that this sequence interacts with a regulatory protein that controls Pof expression. The mutation causing the long-Pof phenotype may be in the gene encoding this protein or in the control region of a structural gene that is regulated by this protein.

Inversion of thermosensing property of the bacterial receptor Tar by mutations in the second transmembrane region

The aspartate chemoreceptor Tar of Escherichia coli serves as a warm sensor that produces attractant and repellent signals upon increases and decreases in temperature, respectively. However, increased levels of methylation of the cytoplasmic domain of Tar resulting from aspartate binding convert Tar to a cold sensor with the opposite signaling behavior. Detailed analyses of the methylation sites, which are located in two separate alpha-helices (MH1 and MH2), have suggested that intra- and/or intersubunit interactions of MH1 and MH2 play a critical role in thermosensing. These interactions may be influenced by binding of aspartate, which could trigger some displacement of MH1 through the second transmembrane region (TM2). As an initial step toward understanding the role of TM2 in thermosensing, we have examined the thermosensing properties of 43 mutant Tar receptors with randomized TM2 sequences (residues 190-210). Among them, we identified one mutant receptor (Tar-I2) that functioned as a cold sensor in the absence of aspartate. This is the first example of attractant-independent inversion of thermosensing in Tar. Further analyses identified the minimal essential divergence from the wild-type Tar sequence (Q191V-W192R-Q193C) required for the inverted response. Thus, displacements of TM2 seem to influence the thermosensing function of Tar.

The polar flagellar motor of Vibrio cholerae is driven by an Na+ motive force

Vibrio cholerae is a highly motile bacterium which possesses a single polar flagellum as a locomotion organelle. Motility is thought to be an important factor for the virulence of V. cholerae. The genome sequencing project of this organism is in progress, and the genes that are highly homologous to the essential genes of the Na+-driven polar flagellar motor of Vibrio alginolyticus were found in the genome database of V. cholerae. The energy source of its flagellar motor was investigated. We examined the Na+ dependence and the sensitivity to the Na+ motor-specific inhibitor of the motility of the V. cholerae strains and present the evidence that the polar flagellar motor of V. cholerae is driven by an Na+ motive force.

Creutzfeldt-Jakob disease with florid-type plaques after cadaveric dura mater grafting

BACKGROUND

Many reported cases of iatrogenic Creutzfeldt-Jakob disease (CJD) developed after grafting cadaveric dura mater contaminated with CJD prions (dura-associated CJD). They are known to be clinicopathologically similar to sporadic CJD. We report herein 2 autopsy cases of dura-associated CJD with atypical clinicopathological features.

PATIENTS

Two patients presented with progressive ataxia and mental deterioration 10 or 11 years after neurosurgical treatment with cadaveric dural grafting, which led to their deaths at 8 and 17 months, respectively, after onset.

RESULTS

The cases were clinically atypical in exhibiting no or late occurrence of myoclonus and periodic synchronous discharges on electroencephalographic studies. They were pathologically unique in several aspects. The most striking feature was the presence of many prion protein (PrP) plaques in multiple areas in the brain. Some of them were the "florid" type surrounded by a zone of spongiform changes known to be a hallmark for the new variant CJD. The distribution of spongiform degeneration was also unique in that it was intense in the thalamus, basal ganglia, and the dentate nuclei of the cerebellum but milder in the cerebrum. There were no mutations in the PrP gene of the patients. There was no major difference in the size and glycoform pattern between the abnormal isoform of PrP extracted from the brain tissue from the dura-associated cases of CJD and that from a sporadic case of CJD.

CONCLUSIONS

These 2 cases are clinicopathologically distinct from typical dura-associated cases of CJD. They may be a subtype with florid-type plaques in dura-associated CJD.

Na+-driven flagellar motor resistant to phenamil, an amiloride analog, caused by mutations in putative channel components

The rotation of the Na+-driven flagellar motor is specifically and strongly inhibited by phenamil, an amiloride analog. Here, we provide the first evidence that phenamil interacts directly with the Na+-channel components (PomA and PomB) of the motor. The alterations in Mpar (motility resistant to phenamil) strains were mapped to the pomA and/or pomB genes. We cloned and sequenced pomA and pomB from two Mpar strains, NMB205 and NMB201, and found a substitution in pomA (Asp148 to Tyr; NMB205) and in pomB (Pro16 to Ser; NMB201). Both residues are predicted to be near the cytoplasmic ends of the putative transmembrane segments. Mutational analyses at PomA-Asp148 and PomB-Pro16 suggest that a certain structural change around these residues affects the sensitivity of the motor to phenamil. Co-expression of the PomA D148Y and PomB P16S proteins resulted in an Mpar phenotype which seemed to be less sensitive to phenamil than either of the single mutants, although motility was more severely impaired in the absence of inhibitors. These results support the idea that PomA and PomB interact with each other and suggest that multiple residues, including Asp148 of PomA and Pro16 of PomB, constitute a high-affinity phenamil-binding site at the inner face of the PomA/PomB channel complex.

Arterial dynamic appearance of common bile duct carcinoma by helical CT on angiography (angio-HCT): four operated cases

We present four cases of common bile duct carcinoma in which both angiographic helical CT (angio-HCT) and pancreatoduodenectomy were done in the 3 years since 1995. Angio-HCT was performed with direct infusion of the contrast medium through the gastroduodenal artery inserted on angiography. Angio-HCT displayed the tumors as lower density areas in contrast to the strong enhancement of the circumferential nontumorous areas, including the pancreas and duodenum.

High-affinity efflux transport system for glutathione conjugates on the luminal membrane of a mouse brain capillary endothelial cell line (MBEC4)

Cumulative evidence suggests that several organic anions are excreted from the brain to the blood across the blood-brain barrier. In the present study, we carried out a kinetic investigation of the transport activity in MBEC4, an immortalized cell line established from BALB/c mouse cerebral microvessel endothelial cells. The presence of an efflux system in intact cells was examined by using monochlorobimane (MCB), which is conjugated with glutathione intracellularly to produce glutathione bimane (GS-B). The efflux of GS-B was inhibited by ATP depletion and also by 1-chloro-2, 4-dinitrobenzne, a precursor of 2,4-dinitrophenyl-S-glutathione, in a concentration-dependent manner. Using this MBEC4 monolayer, we investigated the direction of this transport activity. Although the efflux of GS-B was observed on both luminal and abluminal sides of MBEC4 monolayer, the profile differed for the two sides with respect to the concentration dependence of MCB; the analysis suggested the presence of high-affinity transport system on the luminal side. To investigate the mechanism for the transport, we examined the ATP-dependent uptake of GS-B into the membrane vesicles prepared from MBEC4. ATP-dependent uptake systems with high (Km = 35 nM) and low (Km = 14 microM) affinities were identified. These results suggested that this high-affinity transport system of glutathione conjugates is expressed on the luminal side of the blood-brain barrier and is involved in the detoxification of xenobiotics.

Characteristics of delayed excretion of flavonoids in human urine after administration of Shosaiko-to, a herbal medicine

There has been little explanation of herbal medicines by modern medical sciences, including pharmacokinetics, whereas physicians follow empirical indications written in classical literature. Recent reports of herb-induced adverse reactions compelled us to proceed the investigation of a herbal medicine Shosaiko-to (TJ-9) from a pharmacokinetic point of view. To five healthy volunteers, a single 5 g dose of TJ-9, consisting of 7 herbs, was administered. We conducted HPLC analysis of the timed-urine specimens to disclose the type and amount of compounds excreted. Excretion rate-time curves were analyzed individually. Four flavonoids, liquiritigenin, baicalein, wogonin and oroxylin A, were found both in the urine and TJ-9. The glycosides in TJ-9 were absorbed after microflora hydrolysis. Davidigenin, which was not found in TJ-9, was an intestinal metabolite of liquiritigenin. Also, two flavanones, S-dihydrowogonin and S-dihydrooroxylin A, were identified as the metabolites of wogonin and oroxylin A, respectively. Excretion rate-time curves of the flavonoids were divided into three types of structure-dependent absorption, i.e. (1) the fast absorption of herbal-origin aglycons, (2) the moderately-delayed absorption of aglycons derived from herbal glycosides, and (3) markedly-delayed absorption after the molecular transformation of herbal compounds. Individual excretion profiles seemed to depend on microflora activities. Two types of flavanones, S-dihydrowogonin and S-dihydrooroxylin A, were found in a half of the volunteers, suggesting there might be two kinds of volunteers, namely, rapid and poor metabolizers of flavonoids.

Intersubunit interaction between transmembrane helices of the bacterial aspartate chemoreceptor homodimer

The transmembrane domain that connects the extracellular and intracellular domains of cell-surface receptors must play a critical role in signal transduction. Here, we report studies of the interaction between the transmembrane helices (TM1 and TM2) of the Escherichia coli aspartate chemoreceptor (Tar). Tar exists as a homodimer regardless of its state of ligand occupancy. A particular residue substitution in TM1 (A19K) abolishes the signaling ability of Tar. This signaling defect can be suppressed by single residue substitutions in TM2 (W192R, A198E, V201E, and V202L). We have found that these suppressors can be divided into two groups. A198E and V201E (class 1) almost completely suppress the defects caused by A19K, and this suppression occurs between two subunits of the Tar dimer. In contrast, W192R and V202L (class 2) fail to suppress some signaling defects, and their suppression does not occur between subunits. Because disulfide-crosslinking studies predict that residues 198 and 201 point toward residue 19 of the partner subunit, we propose that the class 1 suppressors form an intersubunit salt bridge with Lys-19. Indeed, A19K was suppressed by several additional aspartate or glutamate substitutions on the same face of TM2 occupied by residues 198 and 201. None of these intersubunit salt bridges perturb signaling function, suggesting that the mechanism of transmembrane signal propagation does not involve large displacements (such as extensive rotation) of the TM1 and TM2 helices relative to each other.

Activation of 11 beta-hydroxysteroid dehydrogenase by dehydroepiandrosterone sulphate as an anti-hypertensive agent in spontaneously hypertensive rats

The anti-hypertensive properties of dehydroepiandrosterone sulphate (DHEAS) have been investigated by studying its effects on blood pressure, on serum concentrations of corticosterone and dehydrocorticosterone, and on 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) activity in spontaneously hypertensive rats (SHR). SHR were given intraperitoneal injections of DHEAS (10 mg day-1 for 70 days) from six to 16 weeks of age. The blood pressure-time curve was significantly (P < 0.05) suppressed immediately after administration of DHEAS. There was no difference between the heart rates of control and DHEAS groups. Serum concentrations of corticosterone and dehydrocorticosterone in the DHEAS group were significantly (P < 0.05) lower than those of the control group. The dehydrocorticosterone/corticosterone concentration ratio was, however, significantly (P < 0.05) higher in the DHEAS group, suggesting that treatment with DHEAS enhanced the overall interconversion of corticosterone to dehydrocorticosterone. The activity of 11 beta-HSD in specific organs of the DHEAS group was affected, characteristic changes being increases in the kidney (14-58%), decreases in the liver (11-27%) and no change in the testis. Direct addition of DHEAS to 11 beta-HSD preparations from the kidneys of control SHR had the same effect as that observed in the in-vivo experiments. The fall in serum corticosterone in the DHEAS group is considered to be related, at least partly, to increased activity of kidney 11 beta-HSD. The inverse correlation of kidney 11 beta-HSD activity with serum corticosterone and blood pressure (-r = 0.628, P < 0.01, and -r = 0.478, P < 0.05, respectively) suggest that DHEAS delayed the development of hypertension in SHR by selective promotion of kidney 11 beta-HSD activity which in turn resulted in lower serum concentrations of corticosterone and its minimal aldosterone-like activity.

Arthropod-borne tularemia in Japan: clinical analysis of 1,374 cases observed between 1924 and 1996

Sixteen cases of tularemia transmitted by arthropods are used to characterize arthropod-borne tularemia in Japan. Arthropod-borne tularemia accounted for 1.2% of a total of 1,374 cases of tularemia observed between 1924 and 1996. The number of cases reported in Japan was low when compared with the number of cases reported in the United States. Arthropod-borne tularemia, however, is increasing and has reached 10.1% incidences during the last 16 yr. No arthropod-borne cases were reported prior to 1951. The occurrence of tularemia infection caused by contact with diseased hares was diphasic with the higher peak occurring during the winter, whereas the occurrence of arthropod-borne tularemia was common from spring to autumn. Among the 16 cases that we studied, 5 were initiated by tick-bites, 5 by the crushing of ticks found on domestic dogs, and 1 by an unidentified insect. In the remaining 5 cases, the vectors were not identified although arthropod bites were confirmed. These arthropod-borne cases were observed exclusively in the northeastern area of Honshu, the main island of Japan, and the age of patients ranged from 23 to 74 yr. The arthropod vectors associated with tularemia and factors influencing incidence of arthropod-borne tularemia in Japan are discussed.

Chiral resolution of four major flavanones in post-administrative urine of Chinese herbal medicines by HPLC on macroporous silica gel coated with cellulose tris(3,5-dimethylphenylcarbamate)

Direct chiral resolution of four major flavanones recovered from post-administrative urine of the traditional Chinese medicines Daisaiko-to and Shosaiko-to was achieved by high-performance liquid chromatography (HPLC) on macroporous silica gel coated with cellulose tris(3,5-dimethylphenylcarbamate), Chiralcel OD. Chromatographic conditions were optimized so as to attain satisfactory enantiomeric resolution of the polysubstituted flavanones. Urinary liquiritigenin and naringenin were considerable mixtures of R and S-enantiomers, while S-enantiomers of dihydrowogonin and dihydrooroxylin A were predominantly excreted. Our chiral HPLC techniques can be applied to pharmacokinetical evaluation of the chiral flavanone enantiomers following oral administration of the herbal medicines.

Individual variations in lymphocyte-responses to glucocorticoids in patients with bronchial asthma: comparison of potencies for five glucocorticoids

Glucocorticoids (GCs) are known to be effective for bronchial asthma, however, a considerable number of asthma patients fail to respond to GC despite the onset of serious side effects. Here we examined individual sensitivities to five clinically-used GCs in 40 asthma patients and 100 healthy subjects. Peripheral-blood mononuclear cells (PBMCs) were isolated from these subjects, and their in vitro sensitivities to hydrocortisone, prednisolone, methylprednisolone, dexamethasone, and betamethasone were determined with a mitogen-assay procedure. The number of PBMCs positive to IL-2 receptors (IL-2Rs) as well as soluble IL-2R (sIL-2R) levels in serum were concomitantly measured in asthma patients, and relationships between these cytokine indices and PBMC-sensitivities to GCs were also examined. Large individual variations in GC IC50s have been observed in PBMCs from asthma subjects, especially in prednisolone IC50s (ranged from 1 to 10,000 ng/ml). When compared with healthy subjects, asthma patients tend to show PBMC-resistance to prednisolone (p < 0.05). Moreover, potencies of methylprednisolone on PBMC-blastogenesis were > 10 times higher than those of prednisolone in both healthy subjects and asthmatics (p < 0.01). In asthma patients, IC50s of hydrocortisone, prednisolone and betamethasone against PBMC-blastogenesis were significantly correlated with elevated percentages of IL-2R-positive PBMCs (p < 0.05), while the IC50 of methylprednisolone showed no such correlation. sIL-2R levels did not correlate with IC50s of any of the GCs examined. Thus, the results showed that a part of asthma patients exhibited PBMC-resistance to GCs, especially to prednisolone. Methylprednisolone potency was unexpectedly higher (> 10 times) than prednisolone potency. Our results also raised the possibility that PBMC-resistance to prednisolone in asthma may correlate with an increase in IL-2R positive PBMCs.

Flagellin-containing membrane vesicles excreted from Vibrio alginolyticus mutants lacking a polar-flagellar filament

Polar flagellum-defective mutants (Pof- Laf-) have been isolated from a lateral flagella-defective mutant (Pof+ Laf-). Among these Pof- Laf- mutants, polar-filamentless mutants, which have the hook structure but not the filament, were identified by electron microscopy. Their hooks were covered with a sheath structure which is contiguous to the outer membrane. The filament proteins, flagellins, were shed into the culture medium of these mutants. These flagellins could be sedimented by high-speed centrifugation even after heat or low pH treatment whereas the depolymerized flagellin of the Pof+ strain was degraded by these treatments. After Triton X-100 treatment, most flagellin of the filamentless mutants could no longer be sedimented, and was degraded. We observed vesicle-like structures on the tips of the hooks and in the flagellin fraction sedimented by high speed centrifugation. These results suggest that flagellin of the filamentless mutants is not assembled into the tip of the hook, but is excreted together with a membrane structure which is probably the sheath of polar flagella.

Stereochemistry and putative origins of flavanones found in post-administration urine of the traditional Chinese remedies shosaiko-to and daisaiko-to

Optically active flavanones, dihydrowogonin and dihydrooroxylin A, were found in the urine of healthy volunteers who orally received the traditional Chinese remedies Shosaiko-to and Daisaiko-to on separate occasions. These remedies, which consisted of dried extracts of Scutellariae Radix and other herbs, contained the metabolic precursors of the flavanones, but not the flavanones themselves, in stoichiometrically sufficient amounts. Structures and stereochemistry of the flavanones were elucidated by UV, circular dichroism (CD), electron impact (EI)-MS and 1H-NMR analyses, showing that the biotransformations from the corresponding flavones, wogonin and oroxylin A, were stereoselective with a preference for the S-enantiomers. The putative origins of the flavanones were confirmed in terms of pharmacokinetics. Renal excretion-time data of the flavanones and the flavones suggested that the stereoselective transformations might have occurred in the intestinal tract as a result of microfloral metabolism before absorption.