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I Yano

Publications and source records attributed to I Yano.

At least 55 records · Page 3Linked to original sources
PubMed1998

Pharmacokinetics and pharmacodynamics of acetazolamide in patients with transient intraocular pressure elevation.

OBJECTIVE: To characterize the pharmacokinetics and pharmacodynamics of acetazolamide in patients with transient intraocular pressure (IOP) elevation and to provide individual patients with the optimal dosage regimen for this drug. METHODS: We studied 17 patients with transient IOP elevation, who were given 62.5-500 mg acetazolamide orally as single or repetitive doses. Plasma acetazolamide concentration and IOP were measured at approximately 1, 3, 5, and 9 h after the last acetazolamide administration. Pharmacokinetics and pharmacodynamics were analyzed by nonlinear mixed-effect modeling using the program NONMEM. RESULTS: The plasma concentration profile of acetazolamide was characterized by a one-compartment model with first-order absorption. The apparent oral clearance was related to the creatine clearance (CCR) which was estimated by the Cockcroft and Gault equation, as follows: 0.0468 x CCR1 x h(-1). The estimated apparent oral volume of distribution, first-order absorption rate constant, and absorption lag time were 0.231 l x kg(-1), 0.821 x h(-1), and 0.497 h, respectively. IOP after oral acetazolamide administration was characterized by an Emax model. The maximal effect in lowering the IOP (Emax) was 7.2 mmHg, and the concentration corresponding to 50% of the maximal effect (EC50) was 1.64 microg x ml(-1). As 70% of Emax was achieved at a plasma concentration of 4 microg x ml(-1), this concentration was considered satisfactory for lowering IOP. The recommended dosage was calculated so that the minimum plasma concentration at steady state exceeded this target concentration; 250 mg t.i.d., 125 mg t.i.d., 125 mg b.i.d., and 125 mg once daily for the patients with CCR values of 70, 50, 30, and 10 ml min(-1), respectively. CONCLUSION: Measuring plasma concentrations of acetazolamide and subsequent pharmacokinetic and pharmacodynamic analyses are useful for estimating its concentration-dependent effectiveness in lowering the IOP in individual patients. The dosage regimen presented in this study is expected to improve the benefits of acetazolamide pharmacotherapy in most elderly patients with transient rises in IOP following intraocular surgery.

Acetazolamide↗
PubMed1998

Effect of clarithromycin on renal excretion of digoxin: interaction with P-glycoprotein.

We present a digoxin-clarithromycin interaction in two patients in whom digoxin concentrations were unexpectedly increased. The ratio of renal digoxin clearance to creatinine clearance in one patient was lower during the concomitant administration of clarithromycin (0.64 and 0.73) than that after cessation of clarithromycin administration (1.30 +/- 0.20; mean +/- SD). Because P-glycoprotein could play an important role in the renal secretion of digoxin, we hypothesized that clarithromycin decreases renal digoxin excretion by inhibiting P-glycoprotein-mediated transport. Digoxin transport was evaluated with use of a kidney epithelial cell line, which expresses the human P-glycoprotein on the apical membrane by transfection with MDR1 complementary deoxyribonucleic acid. Clarithromycin inhibited the transcellular transport of digoxin from the basolateral to the apical side in a concentration-dependent manner and concomitantly increased the cellular accumulation of digoxin. These results suggest that clarithromycin may inhibit the P-glycoprotein-mediated tubular secretion of digoxin, and this interaction mechanism may contribute to an increase in the serum digoxin concentration.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Rapid serodiagnosis of Mycobacterium avium-intracellulare complex infection by ELISA with cord factor (trehalose 6, 6'-dimycolate), and serotyping using the glycopeptidolipid antigen.

Mycobacterium avium-intracellulare complex (MAC) is one of the most important opportunistic pathogens, particularly in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to determine whether an enzyme-linked immunosorbent assay (ELISA) using trehalose 6,6'-dimycolate (TDM) as an antigen can be used for the rapid serodiagnosis of MAC infection. We also identified MAC serotypes by ELISA using serotype-specific glycopeptidolipid (GPL) antigen. To confirm our findings, the thin-layer chromatographic (TLC) behavior of serotype-specific GPL of the strains isolated from MAC-infected patients was also tested. Forty patients infected with MAC and 30 healthy controls were tested. Thirty-two of the 40 MAC-infected patients had higher titers of serum antibodies against MAC TDM than against MTB TDM, while all 30 healthy control sera were unreactive to MAC TDM and MTB TDM. Results of the GPL ELISA indicated that 20 of the 40 MAC-infected patients' sera were reactive against serotype 4 GPL, 3 against serotype 8 GPL, and 1 against serotype 16 GPL. A TLC analysis of the GPL of the 40 MAC isolates showed that 16 strains were of serotype 4, 5 of serotype 8, and 2 of serotype 16. Results of the GPL ELISA were in good accord with those of the TLC analysis for most patients. Our findings suggest that ELISA using TDM is useful for rapid serodiagnosis of MAC infection, and that complementary ELISA testing using serotype-specific GPL gives additional detailed information concerning MAC serotypes.

Adult↗
PubMed1998

Globotriaosyl ceramide and globoside as major glycolipid components of fibroblasts in scirrhous gastric carcinoma tissues.

Scirrhous gastric cancer is characteristic in that cancer cells proliferate and invade with prominent fibrosis. To search for the expression of specific carbohydrate chains in scirrhous gastric cancer, we have examined the glycosphingolipid composition of scirrhous cancer tissues (n=10) in comparison with that of non-scirrhous cancer tissues (n=10) by means of two-dimensional thin layer chromatography, followed by fast atom bombardment mass spectrometry of the individual glycolipids and immunostaining analysis. The major neutral glycosphingolipids from scirrhous gastric cancer tissues were identified as ceramide monohexoside, ceramide dihexoside, globotriaosyl ceramide (Gb3) and globoside (Gb4), while the major acidic glycosphingolipids were II3 NeuAcalpha-LacCer, II3 NeuAcalpha2-LacCer and sulfatide. Relative concentrations of Gb3 and Gb4 in scirrhous gastric cancer tissues (Gb3 + Gb4 = 58%) were two times higher than those in non-scirrhous gastric cancer tissues (29%). Orthotopic fibroblasts cloned from scirrhous gastric cancer tissues showed similar high concentrations of Gb3 and Gb4 to scirrhous gastric cancer tissues. Furthermore, immunohistochemical study revealed that Gb3 and Gb4 were expressed intensely on the fibroblasts. On the other hand, analysis of glycosphingolipids in four scirrhous gastric cancer cell lines yielded the following results. i) The contents of Gb3 and Gb4 were low (6%), compared with orthotopic fibroblasts (62%). ii) Significant amounts of Le(a) (pentaglycosylceramide) and Le(b) (hexa- and heptaglycosylceramides), which could not be detected in scirrhous cancer tissues, were observed. The results show that the major neutral glycosphingolipids such as Gb3 and Gb4 of scirrhous gastric cancer tissues were derived from orthotopic fibroblasts and not from the cancer cells.

Adenocarcinoma, Scirrhous↗
PubMed1998

Increased production of interleukin-10 by human blood monocytes stimulated with Mycobacterium avium-intracellulare complex.

Macrophages produce various cytokines in response to mycobacteria, including interleukin 10 (IL-10) and tumor necrosis factor alpha (TNF-alpha). IL-10 has been shown to down-regulate numerous macrophage functions, including microbicidal activity against intracellular bacteria and parasites. IL-10 also inhibits interferon-gamma (IFN-gamma) production and antigen-specific proliferation of Th1 cells mediating immunologic resistance to mycobacterial infection. In contrast, TNF-alpha activates macrophages and may augment their mycobacterial activity. In this study, peripheral blood mononuclear cells (PBMC) or blood monocytes obtained from healthy tuberculin reactors were stimulated in vitro with heat-killed Mycobacterium tuberculosis or heat-killed M. avium-intracellulare complex (MAC) to produce IL-10 and TNF-alpha. We studied a total of 26 clinical isolates of M. tuberculosis and 28 isolates of MAC. MAC-stimulated PBMC and monocytes released significantly larger amounts of IL-10 than those cells stimulated with M. tuberculosis. However, there was no difference in induction of TNF-alpha production between MAC and M. tuberculosis. When TNF-activity was neutralized by the addition of anti-TNF-alpha mAb in culture, MAC still induced more IL-10 secretion than did M. tuberculosis. These findings suggest that increased production of IL-10 by MAC-stimulated monocytes may play a role in the intractable disease caused by these organisms.

Cells, Cultured↗
PubMed1998

Granuloma formation and in vitro macrophage activation in mice by mycoloyl glycolipids from Nocardia asteroides and related taxa.

Cord factor (trehalose 6,6'-dimycolate: TDM) is a well-known toxic glycolipid in Mycobacterium tuberculosis. We isolated various mycoloyl glycolipids from Nocardia asteroides 23,167 and related species which are closely related taxonomically to Mycobacterium. Since Nocardia is also an opportunistic pathogen co-infected with HIV, we examined in vivo granuloma formation and the in vitro macrophage activation in mice. We found that cord factor (TDM) and glucose monomycolate (GM) from Nocardia asteroides and Rhodococcus species with shorter chain mycolic acids also exhibited distinctive granuloma-forming activity in lungs, spleen and liver in mice and in vitro induction of prostaglandin E2 (PGE2) and interleukin 1 (IL-1) synthesis. We also found that mycoloyl glycolipids possessing trehalose or glucose as a carbohydrate moiety exhibited immunomodulatory activity, and that mycoloyl glycolipids with longer chain mycolic acids exhibited stronger activity in mice than did those with shorter chain mycolic acids. The mycoloyl glycolipids from Nocardia asteroides directly activated macrophages. Stimulation of above concentration with 0.16 microgram/ml of TDM or 0.8 microgram/ml of GM markedly enhanced production of PGE2 by mouse peritoneal macrophages. At higher concentrations above 100 micrograms/ml of TDM or 500 micrograms/ml of GM, IL-1 release was also enhanced.

Animals↗
PubMed1998

[The 72nd Annual Meeting Education Lecture. Cord factor].

Mycobacterial cell wall contains various lipids (glycolipids and phospholipids) to contribute to its hydrophobic property or acid-fastness and these surface molecules contact with host cells in the early step of infection. Among them, cord factor (trehalose 6,6'-dimycolate, TDM or CF) is the most ubiquitous component, which may be a key molecule for pathogenesis and immunity. Initially, cord factor was isolated from a highly virulent strain of M. tuberculosis which grows in the form of serpentine cords, and showed a marked toxicity for mice when it was administrated intravenously. These observations led to the early hypothesis that cell wall components are related to virulence. However, later studies revealed that cord factors were also found in other non-cord-forming mycobacterial species and other mycolic acid-containing bacteria. Structural studies demonstrated that there were various mycoloyl glycolipids differing in carbohydrate moiety such as glucose mycolate, mannose mycolate, arabinose mycolate and fructose mycolate besides trehalose mycolate in acid-fast bacteria. Therefore, the interest has been focused to the structure-activity relationships of mycoloyl glycolipid and to the mechanism of virulence for host animals. So far, it has been demonstrated that cord factor showed lethal toxicity, granuloma forming activity, adjuvant activity, tumor regressing activity and non-specific infection prevention activity in experimental animals. We have extended investigations further on the structure analysis and immunomodifying activities of cord factor and related mycoloyl glycolipids from various species of mycobacteria, nocardia, rhodococci and gordona, and demonstrated that the most activities were shown in trehalose or glucose esters, but not in mannose, arabinose or fructose esters. Furthermore, it was shown that the longer chain-mycoloyl glycolipids showed the higher toxicity and immunomodifying activities. In mice, in vivo, cytokine inducing activities such as IL-1, IFN-gamma, TNF-alpha, GM-CSF and chemotactic factor were observed and in vitro, TNF-alpha, GM-CSF, chemotactic factor, complement, NO, PGE2 inductions and protein kinase C activation were demonstrated. Furthermore, recently, we have demonstrated that cord factor induced a marked thymic atrophy due to the cortical lymphocyte apoptosis before granuloma formation in mice. It was also established that cord factor showed antigenicity in mice and rabbits and human tuberculous patient sera contained specific antibody (IgG) reactive against cord factor. From above results, cord factor seems to be one of the most potent immunomodulators in the mycobacterial cell wall components pathologically and beneficially.

Adjuvants, Immunologic↗
PubMed1998

Efflux of intracellular alpha-ketoglutarate via p-aminohippurate/dicarboxylate exchange in OK kidney epithelial cells.

The involvement of intracellular alpha-ketoglutarate (alpha-KG) in p-aminohippurate (PAH) transport was investigated in OK kidney epithelial cells. Efflux of intracellular alpha-KG from the OK cells to the basolateral side was increased by applying PAH to the basolateral side of the cells. In contrast, the intracellular alpha-KG concentration was not influenced by the addition of PAH. The alpha-KG efflux across the basolateral membrane induced by PAH was higher than that across the apical membrane. Probenecid inhibited the PAH-dependent alpha-KG efflux. The alpha-KG efflux to the basolateral side was saturable with increasing concentration of PAH in the basolateral medium. Antimycin A, a metabolic inhibitor, inhibited [14C]PAH uptake across the basolateral membrane of OK cells in a dose-dependent manner. In addition, both the alpha-KG efflux induced by PAH and the intracellular alpha-KG concentration were decreased by antimycin A dose-dependently. These results directly show that alpha-KG generated by intracellular metabolism is effluxed via PAH/dicarboxylate exchange in the basolateral membrane of OK cells.

Antimycin A↗
PubMed1998

Transport of quinolone antibacterial drugs in a kidney epithelial cell line, LLC-PK1.

The transport of quinolone antibacterial drugs by LLC-PK1 monolayers was examined to characterize the renal tubular secretion of these drugs. The transcellular transport of levofloxacin and grepafloxacin from the basolateral to apical side was larger than the transport in the opposite direction. The basal-to-apical transcellular transport and uptake from the basolateral side of levofloxacin showed concentration dependent saturation with an apparent Michaelis constant (Km) of 0.6 and 13 mM, respectively. Various quinolones (1 mM) inhibited the transcellular transport of levofloxacin, and this inhibition was accompanied by a marked increase of cellular accumulation. These results indicated that quinolones interacted more strongly with the transport system on the apical than the basolateral membrane. Neither tetraethylammonium nor cyclosporin A affected the basal-to-apical transcellular transport and accumulation of levofloxacin. The basal-to-apical transcellular transport of levofloxacin was not influenced by either lowering the pH of the apical side or pretreatment of apical membrane with p-chloromercuribenzene sulfonate. These findings indicate that quinolones are specifically transported from the basolateral to apical side by LLC-PK1 monolayers and have higher affinity for the transport system in the apical membrane, a system distinct from H+/organic cation antiport system.

4-Chloromercuribenzenesulfonate↗
PubMed1998

[Biochemistry and bioactivities of mycobacterial components].

The most characteristic pathological change in mycobacterial infection is caseous necrosis followed by tuberculous cavity formation due to the cellular immunity induced by antigenic proteins and adjuvant active cell wall components. Mycobacterial cell well contains unique hydrophobic compounds possessing mycolic acids (a long branched-chain high molecular weight fatty acid) and shows distinctive properties such as acid-fastness and wax-like hydrophobicity. Mycobacteria do not produce exotoxin and the virulence cannot be determined by a single toxic substance, but the cell wall components to contact with the host cells are the most important surface molecule at the early stage of infection. Cord factor (trehalose 6,6'-dimycolate) is the most classical virulence factor which is lethally toxic for mice. However, cord factor exists among various species of mycobacteria and even in Nocardia and Rhodococcus. Furthermore, cord factor can produce granulomas without protein antigen in mice and it shows antitumor or non-specific prevention promotion of infection and induction promotion of various cytokines. Sulfolipid (tetracyl trehalose sulfate) also plays a role as a virulence factor by phagocytic process inhibition. Glycopeptidolipid (GPL) from M. avium and phenolglycolipid (PGL) from M. leprae also appeared to be immunomodulatory molecules which inhibit the developing of cellular immunity. Lipoarabinomannan (LAM) is also unique amphipatic molecule, like gram-negative endotoxin. Here, we discuss the involvement of various surface molecutes to contribute to pathogenesis in mycobacterial infection and immunity.

Animals↗
PubMed1997

Molecular cloning and characterization of the chromosomal gene for human lactoperoxidase.

Lactoperoxidase (LPO) is an oxidoreductase secreted into milk, and plays an important role in protecting the lactating mammary gland and the intestinal tract of the newborn infants against pathogenic microorganisms. In this study, the human LPO chromosomal gene was molecularly cloned, and its gene organization was determined. The human LPO gene was found to be arranged with the myeloperoxidase (MPO) gene in a tail-to-tail manner. Similar to the human MPO and eosinophil peroxidase (EPO) genes, the human LPO gene is split by 11 introns and spans 28 kb. Unlike most introns in mammalian gene, the 5' splice donor sequence of intron 11 starts with GC instead of GT. When the minigene comprised of exon 11, intron 11 and exon 12 of the human LPO gene was introduced into COS cells, the correct splicing of the intron was found, suggesting the intron 11 of the human LPO gene is functional. The coding sequence of human LPO consists of 2136 bp, and codes for a protein of 712 amino acids. The amino acid sequence of human LPO has 51% similarity with those of both human MPO and EPO, suggesting that these peroxidase genes have evolved from a common ancestral gene. On the other hand, the nucleotide sequences of the 5' promoter regions of these peroxidase genes exhibit no similarity among them, which agrees with their tissue-specific expression.

Amino Acid Sequence↗
PubMed1997

Enzyme immunoassay to detect antituberculous glycolipid antigen (anti-TBGL antigen) antibodies in serum for diagnosis of tuberculosis.

We report the development of an EIA specific for antituberculosis antibody in human serum for the clinical evaluation of tuberculosis. We developed a TLC immunostaining method to detect specific antigens for antibodies in the serum of patients with tuberculosis. The detected specific antigens, TDM and specific gylcolipid fraction, were individually purified from M. tuberculosis H37Rv by column chromatography. The two purified fractions were mixed and the mixture, termed TBGL antigen, was applied to an enzyme immunoassay suitable for the measurement of antituberculosis antibodies in serum. This EIA meets all the requirements of routine clinical assay in terms of sensitivity (detection limit: 0.125 U/ml), reproducibility (total CV : 3.3-6.0%), accuracy (recovery: 96-105%), simplicity and rapidity (< 2.5 h). Clinical validation of the assay was confirmed by the measurement of the anti-tuberculosis antibody in the serum of normal subjects and patients with pulmonary tuberculosis. The EIA tested in this study showed a high serodiagnostic discriminating power (90% sensitivity and 98% specificity).

Adult↗
PubMed1997

Granuloma formation activity and mycolic acid composition of mycobacterial cord factor.

We analyzed the mycolic acid composition of trehalose 6,6'-dimycolate (TDM) obtained from Mycobacterium, using thin layer chromatography, gas chromatography and gas chromatography-mass spectrometry. Utilizing TDM, whose structure was confirmed, granuloma formation in mice was investigated. All TDM used exhibited considerable granuloma formation activity in the lung and spleen. In particular, TDM from M. bovis showed the greatest activity and toxicity among mycobacterial TDM. We therefore discussed the relationship between the chemical structure and granuloma-forming activity of TDM, especially in relation to the structure of mycolic acid in TDM.

Animals↗
PubMed1997

Evaluation of renal tubular secretion and reabsorption of levofloxacin in rats.

PURPOSE: Levofloxacin, a quinolone antibacterial drug, is a zwitterion at physiological pH. We examined the effect of cationic and anionic drugs on renal excretion of levofloxacin by means of in vivo clearance to characterize the mechanisms of renal excretion of this drug. METHODS: In vivo clearance was studied in male Wistar albino rats. A bolus dose of 2.85 mg/kg of levofloxacin was administered, followed by a constant infusion of 7.08 micrograms/min. Cimetidine, tetraethylammonium, or p-aminohippurate was administered as a bolus and incorporated into the infusion solution. After reaching steady state, urine and blood concentrations were measured, and pharmacokinetic parameters were calculated. RESULTS: Renal clearance was 2.56 +/- 0.42 ml/min in control, which accounted for 34% of the total body clearance. Renal clearance was significantly decreased to 0.83 +/- 0.25 ml/min by cimetidine (p < .05), corresponding to 32% of the control value. The cationic drug, tetraethyl-ammonium also reduced the renal clearance of levofloxacin, but the effect of the anionic drug, p-aminohippurate, was slight. The clearance ratio of levofloxacin, which was calculated by renal clearance divided by the plasma unbound fraction and the glomerular filtration rate, was 1.60 +/- 0.38 in the control and it was decreased to 0.68 +/- 0.17 and 1.11 +/- 0.22 by cimetidine and tetraethylammonium, respectively. CONCLUSIONS: The present results suggest that the renal excretion of levofloxacin in rats involves tubular secretion and reabsorption, in addition to glomerular filtration, and that tubular secretion is inhibited by cimetidine.

Animals↗
PubMed1997

Stimulatory effect of gangliosides on phagocytosis, phagosome-lysosome fusion, and intracellular signal transduction system by human polymorphonuclear leukocytes.

Gangliosides are known to be differentiation-inducing molecules in mammalian stem cells. We studied the interaction between the molecular structure of glycosphingolipids (GSLs) and their promoting mechanisms of the phagocytic processes in human polymorphonuclear leukocytes (PMN). The effect of various gangliosides from mammalian tissues on adhesion, phagocytosis, phagosome-lysosome (P-L) fusion and superoxide anion production was examined by human PMN using heat-killed cells of Staphylococcus aureus-coated with GSLs. Gangliosides GM3, GD1a, GD3 and GT1b showed a marked stimulatory effect on the phagocytosis and P-L fusion in a dose-dependent manner, while ganglioside GM1, asialo GM1 and neutral GSLs did not. The relative phagocytic rate of ganglioside GM3-coated S. aureus was the highest among the tested GSLs. Both P-L fusion rate and phagocytosis of S. aureus were elevated significantly when coated with ganglioside GD1a, GD3 or GT1b, and GT1b gave a five times higher rate than that of the non-coated control. These results suggest that the terminal sialic acid moiety is essential for the enhancement of phagocytosis and that the number of sialic acid molecules in the ganglioside is related to the enhancement of the P-L fusion process. On the other hand, the superoxide anion release from PMN was not affected by ganglioside GM2, GM3, GD1a or GT1b. Furthermore, to clarify the trigger or the signal transduction mechanism of phagocytic processes, we examined the effect of protein kinase inhibitors such as H-7, staurosporine (protein kinase C inhibitor), H-89 (protein kinase A inhibitor), genistein (tyrosine kinase inhibitor), ML-7 (myosin light chain kinase inhibitor), and KN-62 (Ca2+/calmodulin-dependent protein kinase II inhibitor) on ganglioside-induced phagocytosis. H-7, staurosporine and KN-62 inhibited ganglioside-induced phagocytosis in the range of concentration without cell damage, while H-89, genistein and ML-7 did not. Moreover, H-7 and KN-62 inhibited ganglioside-induced P-L fusion. These results suggest that protein kinase C and Ca2+/calmodulin-dependent protein kinase II may be involved in the induction of phagocytosis and P-L fusion stimulated by gangliosides.

Bacterial Adhesion↗
PubMed1997

Studies of polymorphic DNA fingerprinting and lipid pattern of Mycobacterium tuberculosis patient isolates in Japan.

Strain differentiation by DNA restriction fragment length polymorphism (RFLP) has been used mainly for the epidemiological purpose of Mycobacterium tuberculosis infection. In this study, we tried to connect the molecular and phenotypic characteristics of M. tuberculosis patient isolates by comparing the DNA fingerprints obtained by RFLP using IS6110 and lipid patterns using two-dimensional thin-layer chromatography (2-D TLC) with silica gel, since M. tuberculosis has a lipid-rich cell envelope which contributes to the virulence and immunomodulatory properties. We found that 66 isolates of M. tuberculosis from tuberculosis patients showed that the occurrence of IS6110 varied from 1 to 24 copies. The IS6110 patterns were highly variable among isolates. Fifty different RFLP patterns were observed, and 12 RFLP patterns were shared by two or more strains. By computerized analysis of the RFLP patterns of M. tuberculosis patient isolates, we found that 95% of the isolates fell into seven clusters, from A to G, with at least two isolates in each (> 30% similarity). Among the cellular lipids, the phospholipid composition did not differ by strain, whereas the glycolipid pattern differed markedly. Especially, the relative concentration of cord factor and sulfolipid, both of which were known as virulent factors, varied by strain. The fingerprints of some strains showed an association between the DNA and glycolipid patterns, even though some of the same DNA fingerprint strains showed differences in lipid patterns. Among the patient isolates, M. tuberculosis strain 249 possessed a specific glycolipid with 2-O-methyl-L-rhamnose and L-rhamnose, which is rarely found in other strains. This glycolipid showed serological activity against the sera of tuberculosis patients, even if the reactivity was not as strong as trehalose dimycolate. It also showed the inhibition of phagosome-lysosome fusion in macrophages, suggesting involvement with virulence. These results suggest that RFLP analysis using IS6110 is useful for clustering the human isolates of M. tuberculosis, however, for further strain differentiation on virulence, a lipid analysis provides more information.

Antibodies, Bacterial↗
PubMed1997

In vivo induction of apoptosis in the thymus by administration of mycobacterial cord factor (trehalose 6,6'-dimycolate).

It is reported that some bacteria or bacterial components cause thymic atrophy via the apoptotic process. The present study demonstrated for the first time in vivo induction of apoptosis in the mouse thymus by mycobacterial cord factor (CF) (trehalose 6,6'-dimycolate). When 300 microg of purified CF from Mycobacterium tuberculosis was intravenously administered to BALB/c mice in the form of water-in-oil-in-water (w/o/w) emulsion, thymic atrophy and pulmonary granulomas were induced with a peak on day 7, whereas, in the form of liposomes, CF induced thymic atrophy on days 14 to 21 in parallel with the development of hepatic granulomas. Thymic atrophy resulted from the depletion of cortical lymphocytes via apoptosis as revealed by DNA fragmentation and karyorrhectic changes. In contrast, mycobacterial sulfatide (2,3,6,6'-tetraacyl trehalose 2'-sulfate) caused neither thymic atrophy nor granuloma formation. Compared to lipopolysaccharide-induced thymocyte apoptosis, CF (w/o/w)-induced thymocyte apoptosis developed more slowly, reached a maximum later, and lasted longer but was less intense. Although serum tumor necrosis factor alpha (TNF-alpha) levels in CF-treated mice were not significantly elevated, administration of anti-TNF-alpha antibody almost completely inhibited thymic atrophy and granuloma formation. Serum corticosterone levels were only slightly elevated by CF administration. The present results indicate that mycobacterial CF induces thymic atrophy via apoptosis, which is closely linked with granuloma formation.

Animals↗