Spaceflight downregulates antioxidant defense systems in rat liver

Liver antioxidant enzyme activities, mRNA abundance, and glutathione (GSH) status were investigated in male Sprague-Dawley rats placed in an enclosure module aboard Space Shuttle STS-63 for 8 d (F, n = 6). F animals were compared to rats housed in an enclosure module on the ground (G, n = 9), which simulated the vibration and temperature conditions associated with launch and flight, and rats kept under conventional ground vivarium conditions in individual cages (V, n = 6). Spaceflight significantly decreased catalase, GSH reductase, and GSH sulfur-transferase activities in the liver (p < .05). Neither enzyme activity nor enzyme protein content of Cu-Zn and Mn superoxide dismutase (SOD) was affected by flight. The relative abundance of mRNA for Cu-Zn SOD and catalase was significantly decreased comparing F with G rats (p < .05). Spaceflight resulted in a dramatic decrease of liver GSH, glutathione disulfide, and total GSH contents (p < .01), which were accompanied by a lower gamma-glutamyl transpeptidase activity (p < .05). F rats showed a 47% (p < .05) increase in liver malondialdehyde concentration compared to G and V rats. Liver protein content was not affected by flight. These results indicate that spaceflight can downregulate antioxidant defense capacity and elicit an oxidative stress in the liver.

Effect of age on brown adipose tissue activity in the obese (ob/ob) mouse

Brown adipose tissue (BAT), a highly thermogenic tissue in young animals, is relatively atrophied and thermogenetically quiescent (e.g. as measured by colonic temperature) in mice that are obese or old. The aim of the current study was to investigate the effect of aging (3.1 (young) versus 14.6 (old) months old) on BAT activity in lean and obese (ob/ob) mice. In young but not in old mice, BAT mass in terms of weight per unit body weight was significantly lower in obese mice than in lean mice. A significant increase in BAT mass of obese mice with age was noted in terms of weight or weight per unit body weight, probably because of a tendency to become white adipose tissue and the deposit of fat, accompanied by the lowest levels of total protein, guanosine 5'-diphosphate binding, and uncoupling protein (UCP) antigen in the mitochondria of BAT, as well as the lowest colonic temperature among the groups examined. Unlike old lean animals, the old obese (ob/ob) animals did not increase but rather decreased the expression of mRNA for UCP in the mitochondria of BAT. These findings suggest that a marked decrease in BAT thermogenic capacity and activity is noted in old obese mice, probably due to synergism of aging and obesity.

Detection of t(8;14)(q24;q32) by polymerase chain reaction for long DNA targets: a report of two patients with B-cell non-Hodgkin's lymphoma

We developed a novel technique for long-distance polymerase chain reaction (LD-PCR) to detect t(8;14)(q24;q32). LD-PCR can amplify up to 12 kb of DNA encompassing the c-MYC and constant regions of the immunoglobulin heavy chain gene. In this report, we present two patients with B-cell non-Hodgkin's lymphoma. Clinical materials obtained from these patients were examined by LD-PCR. One patient had small noncleaved cell lymphoma (case 1) and the other had diffuse large cell lymphoma (case 2). Both patients showed central nervous system involvement. LD-PCR using appropriate primer pairs and a newly available Taq polymerase for longer product synthesis detected a 9.6 kb (case 1) and a 2.4 kb (case 2) c-MYC/C gamma fusion product indicative of t(8;14) in all materials in which lymphoma cells were shown positive by microscopic examination. LD-PCR provides an advantage in rapid detection of lymphoma cells carrying t(8;14).

Refinement of the BCL2/immunoglobulin heavy chain fusion gene in t(14;18)(q32;q21) by polymerase chain reaction amplification for long targets

The t(14;18)(q32;q21) translocation, involving the BCL2 gene and junctional segments (JH) of the immunoglobulin heavy chain gene (IGH), constitutes the most common chromosomal translocation in non-Hodgkin's lymphoma of B-cell type. Although the breakpoints in BCL2 are largely clustered within the major breakpoint region (MBR) and minor cluster region (mcr), it is known that some breakpoints map away from these regions, resulting in negative amplification of the junctional sequence by polymerase chain reaction (PCR) for < 1 kb targets. To circumvent this problem, we applied a novel PCR technology for long DNA targets, long-distance (LD-) PCR, to the detection of t(14;18) in clinical materials. Oligonucleotide primers were designed to be quite distant from the two known cluster regions in BCL2, and those for the corresponding IGH were complementary to the enhancer and constant regions. In all 52 cases identified as carrying BCL2/JH fusion by conventional Southern blot analysis, LD-PCR successfully amplified fragments encompassing the junctions, which were readily identifiable on ethidium bromide-stained gel. The size of the LD-PCR products ranged from 3.9 kb to 10.7 kb in MBR/IGH fusion and 1.9 kb to 16 kb in mcr/IGH fusion. Furthermore, we established an LD-PCR protocol for > 20 kb targets, which covered the intervening region between the MBR and mcr. Restriction analysis of the LD-PCR products revealed that breakpoints in 33 cases fell within the 150 bp-MBR region, and in 3 cases were within the mcr determined previously by others. In contrast, the breakpoints of the remaining 16 cases were distributed over a large region from the MBR through mcr. Nucleotide sequence analysis of a potential cluster region revealed the presence of an Alu repeat sequence. Restriction analysis of LD-PCR products with BstEII demonstrated a predominant usage of the JH6 segment (71%) at the BCL2/JH junctions. LD-PCR using primers for the constant region genes showed that class switch recombination occurred in more than 80% of the IGH genes on the der(14) chromosome. Our study showed that LD-PCR was capable of detecting virtually any t(14;18) that occurred within the approximately 30 kb region downstream of the MBR, and thus is suitable for initial diagnosis of lymphoma tissues. Furthermore, as amplified fragments obtained by the LD-PCR contained distinctive regions of BCL2 and IGH, restriction analysis and nucleotide sequencing of the products refined the characteristics of t(14;18).

Polymerase chain reaction amplification of long DNA targets: application to analysis of chromosomal translocations in human B-cell tumors (review)

Chromosomal translocations in human leukemias generate fusion transcripts containing messages from two genes involved in the translocation, and these have been the targets for reverse transcriptase-mediated polymerase chain reaction (PCR). In contrast, many of the translocations in B-cell tumors involve immunoglobulin gene (IG) loci, and coding regions of the oncogenes on partner chromosomes are not interrupted by the translocation. Therefore, targets for PCR amplification are single-copy oncogene/IG fusion sequences within the complex genomic DNA. We present here a novel strategy for detection of translocations in B-cell tumors on the basis of long-distance (LD-) PCR that is capable of amplifying up to 30 kb of DNA. LD-PCR is a general method using primer pairs designed for distinctive regions of IG and oncogenes involved in translocations, and amplifying long DNA fragments encompassing the oncogene/IG junction. LD-PCR is capable of detecting virtually all the important translocations in B-cell tumors, including t(8;14)(q24;q32), t(14;18)(q32;q21), t(3;14)(q27;q32) and its variants. We show here that LD-PCR can substitute for time-consuming Southern blot hybridization in the rapid detection of these translocations. Furthermore, as amplified fragments obtained by LD-PCR contained exons and flanking sequences of the oncogenes and IGs, restriction analysis and nucleotide sequencing of the products refined the characteristics of translocations.

Association with FcRgamma is essential for activation signal through NKR-P1 (CD161) in natural killer (NK) cells and NK1.1+ T cells

Natural killer (NK) cells exhibit cytotoxicity against variety of tumor cells and virus-infected cells without prior sensitization and represent unique lymphocytes involved in primary host defense. NKR-P1 is thought to be one of NK receptors mediating activation signals because cross-linking of NKR-P1 activates NK cells to exhibit cytotoxicity and IFN-gamma production. However, molecular mechanism of NK cell activation via NKR-P1 is not well elucidated. In this study, we analyzed the cell surface complex associated with NKR-P1 on NK cells and found that NKR-P1 associates with the FcRgamma chain which is an essential component of Fc receptors for IgG and IgE. The association between FcRgamma and NKR-P1 is independent of Fc receptor complexes. Furthermore, NK cells from FcRgamma-deficient mice did not show cytotoxicity or IFN-gamma production upon NKR-P1 cross-linking. Similarly, NK1.1+ T cells from FcRgamma-deficient mice did not produce IFN-gamma upon NKR-P1 crosslinking. These findings demonstrate that the FcRgamma chain plays an important role in activation of NK cells via the NKR-P1 molecule.

Cysteinyl leukotrienes induce nasal symptoms of allergic rhinitis via a receptor-mediated mechanism in guinea pigs

To examine whether cysteinyl leukotrienes (cysLTs: LTC4, LTD4 and LTE4) induce symptoms of allergic rhinitis via their receptors, we studied the following: i) the specific binding of radiolabeled cysLTs to guinea pig nasal mucosa membrane and ii) effects of nasal LTD4 challenge in normal guinea pigs. The binding study indicated that there was a single population of binding sites for LTC4, LTD4 and LTE4 with Kd and Bmax values of 34.9+/-2.0, 0.252+/-0.015 and 0.589+/-0.039 nM and 10, 140+/-490, 122+/-11 and 306+/-23 fmol/mg protein, respectively. The in vivo study showed that topical nasal challenge of LTD4 (0.1-30 microg/nose) increased nasal secretion, nasal airway resistance and nasal eosinophil infiltration without inducing sneezing. While the increases in nasal secretion and nasal airway resistance were transient, peaking 10 to 20 min after LTD4 challenge, nasal eosinophil infiltration persisted at least until 24 hr post-challenge. These nasal symptoms were dose-dependently suppressed by oral administrations of pranlukast (0.3-3 mg/kg). The results suggest that cysLTs cause not only early-phase symptoms but also nasal eosinophil migration, a characteristic associated with the late-phase symptom of allergic rhinitis, via a receptor-mediated mechanism. Cysteinyl leukotrienes, thus, may be important mediators in allergic rhinitis.

Effects of a specific cysteinyl leukotriene antagonist, pranlukast, on antigen-induced cysteinyl leukotriene-mediated rhinitis in guinea pigs

To examine the effects of a specific cysteinyl leukotriene (cysLT) antagonist, pranlukast, on allergic rhinitis, antigen-induced rhinitis in guinea pigs was modified by pretreatment with an cyclooxygenase inhibitor (indomethacin) followed by an H1-blocker (pyrilamine). Intranasal ovalbumin (OVA) administration in actively sensitized guinea pigs resulted in concentration-dependent increases in nasal permeability and nasal airway resistance (NAR). Although pyrilamine (1 mg/kg, i.v.) abolished these antigen-induced changes, pretreatment with indomethacin (5 mg/kg, i.v.) followed by pyrilamine enhanced these responses to a degree similar to that observed with OVA challenge alone. Analyses of nasal perfusate in indomethacin/pyrilamine-pretreated animals showed that cysLTs increased by 270.8%, whereas thromboxane B2 decreased by 88.3% as compared with those on challenged with OVA alone. Oral administration of pranlukast (1-10 mg/kg) dose-dependently prevented increases in nasal permeability and NAR of indomethacin/pyrilamine-pretreated animals. However, an anti-allergic agent, azelastine, did not affect these responses. These results indicate that pranlukast suppresses antigen-induced cysLT-mediated responses of allergic rhinitis in actively sensitized guinea pigs. A cysLT antagonist, pranlukast, may thus prevent cysLT-mediated symptoms of allergic rhinitis.

Interaction of endocytic signals from the HIV-1 envelope glycoprotein complex with members of the adaptor medium chain family

The envelope glycoprotein (Env) complex of HIV-1 undergoes rapid internalization from the plasma membrane of human cells by virtue of a tyrosine-based endocytic signal (RQGYSPL, residues 704-710) in the cytosolic tail of the protein (J. F. Rowell et al., J. Immunol. 155, 473-488, 1995). Here we demonstrate that this tyrosine-based signal interacts with the mu 2 (medium) chain of the AP-2 clathrin-associated adaptor, a protein complex involved in endocytosis of cell surface receptors. The same signal is also capable of interacting with two other members of the adaptor medium chain family, mu 1 and mu 3A, which are components of the AP-1 and AP-3 adaptor complexes, respectively. Interactions with mu 1 and mu 3A might be responsible for the targeting of the internalized envelope glycoprotein to lysosomes or to the basolateral plasma membrane of polarized epithelial cells. A second potential tyrosine-based signal (LFSYHRL, residues 760-766) also interacts with mu 1, mu 2, and mu 3A, although it is less important for internalization in vivo probably due to its position within the cytosolic tail. Overexpression of chimeric proteins having the HIV-1 Env cytosolic tail increases expression of the transferrin receptor on the cell surface, probably due to saturation of the cellular pool of mu 2 by the overexpressed proteins. These observations suggest that HIV-1 Env utilizes the protein sorting machinery of the host cells for internalization and sorting at various steps of the endocytic and biosynthetic pathways.

Lengthening of the lower limbs in patients with achondroplasia and hypochondroplasia

Ten years of experience in lower limb lengthening achieved in 35 patients with achondroplasia and seven patients with hypochondroplasia is reported. A uniform method of callus distraction (callotasis) was used in all cases, although the order of lengthening of each bone differed among the cases. The mean age of the patients at the time of first operation was 14.5 years; at followup, the mean age was 18.8 years. The mean lengthening achieved in the femur was 7.2 cm (range, 4.5-12 cm) and in the tibia 7.1 cm (range, 4.5-13 cm). More lengthening was achieved in the more recent cases. The function of lengthened limbs, evaluated by physical strength tests, was better at followup than before lengthening in the growing children, although the mechanical axes of the lengthened bones were not necessarily in correct alignment.

Combination therapy with fluconazole and flucytosine for pulmonary cryptococcosis

We investigated, in vitro, the combined effects of fluconazole (FLCZ) and flucytosine (5-FC) against different strains of Cryptococcus neoformans, and retrospectively analyzed the clinical efficacy of combination therapy of FLCZ and 5-FC in patients with pulmonary cryptococcosis. The minimum inhibitory concentrations (MICs) of antifungal agents and drug interaction were determined by the broth microdilution method and checkerboard titration. FLCZ and 5-FC showed synergistic activity against 8 (32%) of 25 strains of C. neoformans. The clinical efficacy of the 2 drugs when combined together was good in 9 (90%) patients and fair in 1 (10%) patient with pulmonary cryptococcosis. Renal dysfunction occurred in 1 patient. Our results suggest that a combination therapy using FLCZ and 5-FC is clinically useful in patients with pulmonary cryptococcosis who otherwise show a limited response to monotherapy.

Endurance training improves the resistance of rat diaphragm to exercise-induced oxidative stress

The current study was designed to test the hypothesis that endurance training improves the ability of the diaphragm muscle to resist exercise-induced oxidative stress. Twenty-eight male Wistar rats were assigned to either untrained or trained groups. Trained rats were treadmill-trained for 9 wk. Each group was subdivided into acutely exercised or nonexercised groups. Diaphragm muscle from each rat was analyzed to determine the levels of certain antioxidant enzymes: Mn-superoxide dismutase (Mn-SOD), Cu,Zn-superoxide dismutase (Cu,Zn-SOD), glutathione peroxidase, and catalase. In addition, interleukin-1 and myeloperoxidase levels were determined. Endurance training upregulated all of the antioxidant enzymes. Conversely, acute exercise increased glutathione peroxidase and catalase in untrained rats, while it had no overt effect on any antioxidant enzymes in trained rats. Both Mn-SOD and Cu,Zn-SOD contents and activities were increased with endurance training. However, the mRNA expressions of both forms of SOD did not show any significant change with endurance training. Acute exercise also increased the levels of interleukin-1 and myeloperoxidase in untrained rats but not in trained rats. Moreover, acute exercise significantly increased the ability of neutrophils to produce superoxide, especially in untrained rats. The results from this study demonstrate that endurance training can upregulate certain antioxidant enzyme activities in rat diaphragm muscle, indicating the potential for improvement of the resistance to intracellular reactive oxygen species. The results of this study also suggest that acute exercise may cause oxidative damage in rat diaphragm through the activation of the inflammatory pathway and that endurance training may minimize such an extracellular oxidative stress by acute exercise.

Functional domain mapping of the clathrin-associated adaptor medium chains mu1 and mu2

The clathrin-associated adaptors AP-1 and AP-2 are heterotetrameric complexes involved in the recognition of sorting signals present within the cytosolic domain of integral membrane proteins. The medium chains of these complexes, mu1 and mu2, have been implicated in two types of interaction: assembly with the beta1 and beta2 chains of the corresponding complexes and recognition of tyrosine-based sorting signals. In this study, we report the results of a structure-function analysis of the mu1 and mu2 chains aimed at identifying regions of the molecules that are responsible for each of the two interactions. Analyses using the yeast two-hybrid system and proteolytic digestion experiments suggest that mu1 and mu2 have a bipartite structure, with the amino-terminal one-third (residues 1-145 of mu1 and mu2) being involved in assembly with the beta chains and the carboxyl-terminal two-thirds (residues 147-423 of mu1 and 164-435 of mu2) binding tyrosine-based sorting signals. These observations support a model in which the amino-terminal one-third of mu2 is embedded within the core of the AP-2 complex, while the carboxyl-terminal two-thirds of the protein are exposed to the medium, placing this region in a position to interact with tyrosine-based sorting signals.

Relationship between cold tolerance and generation of suppressor macrophages during acute cold stress

Acute cold stress induces suppressor macrophages expressing large numbers of receptors to the crystallizable fragment (Fc) portion of immunoglobulin G (MAC-1+ FcgammaRII/IIIbright cells), resulting in the immunosuppression of splenocyte mitogenesis. The generation of MAC-1+ FcgammaRII/IIIbright cells is mediated by the action of glucocorticoids (GCs) through the GC-receptor. In the present study, the generation of MAC-1+ FcgammaRII/IIIbright cells in peritoneal exudate cells was closely related to the decrease of rectal temperature during 3-day exposure to 5 degrees C. We next investigated the effects of improved cold tolerance on the generation of MAC-1+ FcgammaRII/IIIbright cells during acute cold stress. Mice were adapted to cold by exposure to 5 degrees C for 3 wk (cold-acclimated mice) and then reexposed to 5 degrees C for 3 h (acute cold stress) after living at 25 degrees C for 24 h. The rectal temperature of cold-acclimated mice was not decreased by the acute cold stress. In addition, the proportion of MAC-1+ FcgammaRII/IIIbright cells in peritoneal exudate cell population from cold-acclimated mice was unaffected by the acute cold stress. The cold acclimation significantly attenuated the increases in serum corticosterone levels and the expression of the GC-receptor mRNA on peritoneal exudate cells in response to acute cold stress. These results suggest that the altered GC response to acute cold stress by the improvement of cold tolerance inhibits the generation of suppressor macrophages during acute cold stress.

[Relationship between streptomycin susceptibility and rpsL mutations of Mycobacterium tuberculosis strains]

The relationship between streptomycin (SM) susceptibility and rpsL mutations of Mycobacterium tuberculosis strains was studied. Of 18 clinically isolated SM-resistant M.tuberculosis strains, mutation was suspected in 9 strains (50%) with SM MICs of > or = 256 micrograms/ml by PCR-single strand conformation polymorphism targeting rpsL gene. On the other hand, using PCR-direct sequence method, amino acid substitution caused by single nucleotide point mutation in rpsL gene was demonstrated in 11 out of 18 strains (61%). The same amino acid substitution at codon 43 (Lys-->Arg) was observed in all 11 strains with SM MICs of > or = 256 micrograms/ml. In addition, PCR products obtained from these 11 strains could not be cut by a restriction enzyme, Mbo II, while H37Rv strain and the other 32 strains with SM MICs of < 256 micrograms/ml were cut into 2 fragments. In conclusion, our results suggest that highly SM-resistant M.tuberculosis strains with MICs of > or = 256 micrograms/ml could be rapidly and easily detected by the restriction enzymatic method.

Significance of rearrangement of the BCL6 gene in B-cell lymphoid neoplasms

Chromosomal translocations involving 3q27 are among the most common recurring translocations in non-Hodgkin's lymphoma (NHL) of B-cell phenotype. Molecular cloning of junctional areas of the translocations resulted in isolation of the BCL6 gene adjacent to the breakpoint cluster on 3q27. The gene encodes a zinc-finger transcription factor which is expressed in nuclei of germinal center B-cells. Rearrangement of BCL6 was observed in 6.4 to 14.3% of follicular lymphomas and 28.6 to 35.5% of diffuse large cell lymphomas; regarding the latter, a Japanese series showed a lower incidence. Survival curves suggested that NHL carrying rearrangement of BCL6 and lacking that of BCL2 is curable by chemotherapy. Detailed analysis of the vicinity of translocations showed that the 5' untranslated region of BCL6 was replaced by heterogeneous promoters not only from immunoglobulin genes but also from many previously uncharacterized loci. Bcl-6 protein is expressed in NHL of follicular center B-cell origin, independently of the presence or absence of BCL6 rearrangement. At present, limited information is available about the functional consequences of the rearrangements and, in particular, about their ultimate implications for lymphomagenesis.

[Allogeneic peripheral blood stem cell transplantation for multiple myeloma]

We report here with a 46-year-old man with refractory multiple myeloma receiving allogeneic peripheral blood stem cell transplantation from his HLA-matched brother. The preparative regimen consisted of TBI (12Gy), VP16 (15 mg/kg) and cyclophosphamide (120 mg/kg). GVHD prophylaxis consisted of cyclosporin A and short course of methotrexate. The donor received G-CSF at 10 micrograms/kg/day for 5 consecutive days and underwent leukapheresis on days 5 and 6. The neutrophil recovery to 500/microliter and platelet recovery to 20,000/microliter were day 12 and day 15, respectively. The patient is currently well with no GVHD or graft failure and a complete donor's chimerism.

Induced thermostability of poly(ethylene oxide)-modified hemoglobin in glycols

The thermostability and redox activity of poly(ethylene oxide) (PEO)-modified human hemoglobin in PEO200 (PEO containing KCl, average MW of 200, < 0.3% H2O) were investigated by UV-vis spectroscopy, by circular dichroism spectroscopy, and by cyclic voltammetry. Using PEO oligomers as a solvent, PEO-modified hemoglobin was reduced and oxidized at an indium tin oxide glass electrode in the temperature range of -10 to 120 degrees C. The thermostability of PEO-modified hemoglobin was affected by the molecular weight of the solvent PEO. In lower-molecular weight glycols (MW of < 150), PEO-modified hemoglobin was denatured within a few minutes at 80 degrees C. On the other hand, the absorbance at the Soret band for PEO-modified hemoglobin was unchanged for 2 h at 80 degrees C in PEO200. A decrease in the water content of solvent PEO200 also improved the thermostability of PEO-modified hemoglobin. Improvement in the thermostability was attributed to physicochemical characteristics such as the relatively low molecular motion of PEO oligomers used as a solvent.

BCL3 rearrangements and t(14;19) in chronic lymphocytic leukemia and other B-cell malignancies: a molecular and cytogenetic study

The t(14;19)(q32.3;q13.1) is a recurring translocation found in the neoplastic cells of some patients with chronic lymphocytic leukemia (CLL) or other B-lymphocytic neoplasms. We previously cloned the translocation breakpoint junctions present in the leukemic cells from three such patients and identified a gene, BCL3, whose transcription is increased as a result of the translocation. In the present paper, we describe three additional patients with the t(14;19), one with lymphoma and two with CLL, and report the cloning and sequencing of the breakpoint junction in one of these patients as well as in a previously reported patient. We and others have found that the breakpoints on chromosome 14, with one exception, fall within the switch region upstream of the immunoglobulin heavy chain C alpha 1 or C alpha 2 sequences. Several of the breaks within chromosome 19 fall immediately upstream of the BCL3 gene, but several others are more than 16 kb 5' of the gene. Most patients with CLL and the t(14;19) also show trisomy 12.

Purification and characterization of an Aspergillus oryzae-produced carboxylesterase that catalyzes O-deacetylation of a fully acetylated O-glucoside of N-phenylacetohydroxamic acid

A carboxylesterase [2,3,4,6-tetra-O-acetyl-1-[(N-acetyl-N-phenylamino)oxy]-1-deoxy-beta-D-g lucopyranoside (GPA) O-deacetylase] from a culture product of Aspergillus oryzae (Taka diastase) was purified 8500-fold with a yield of 3%. The molecular mass of the purified enzyme was shown to be 35 +/- 1 kDa by SDS/PAGE. The enzyme shows a selective O-deacetylation activity of GPA to give the fully O-deacetylated glucoside. Among the substrates tested, the enzyme did not hydrolyze benzoyl and phenylacetyl esters and acetamides. In the hydrolysis of p-nitrophenyl esters, the acyl preference is acetyl > propionyl > butyryl, judging from the Vmax/Km values. A good correlation between log(Vmax/Km) and the Taft's Es constant of the alkyl group of the acyl moiety was obtained. The optimum pH was around 7.3 at 37 degrees C, and the enzyme was inhibited by mercuric chloride, p-chloromercuribenzoate and diisopropyl fluorophosphate. This enzyme should be useful for the selective removal of acetyl groups that serve to protect hydroxyl groups during carbohydrate synthesis.

Human hepatitis B virus enhancer 1 is responsive to human interleukin-6

Serum levels of interleukin-6 (IL-6) are elevated in acute and chronic hepatitis B patients. The effect of IL-6 and its transcription factor of NF-IL6 (a nuclear factor for IL-6) on hepatitis B virus (HBV) enhancer 1 (Enh1), which controls HBV X expression, were investigated in HepG2 cells. Twenty ng/ml of IL-6 increased 4-fold the enhancer activity of Enh1 according to the CAT assay. The IL-6 stimulation was abolished by introducing a mutation either in an AP-1-related site or a C-stretch sequence in the Enh1 sequence, demonstrating that the cis-elements are necessary for the IL-6 response. Co-transfection of NF-IL6 expression plasmid similarly increased the enhancer activity of Enh1 through both binding sites. Further, a specific complex formation of the Enh1 was detected using HepG2 nuclear lysates by electromobility shift assays, and the complex formation was increased in the lysates of cells treated with IL-6 and NF-IL6-transfection. In competition assays, one half of the complex formed was found to remain in the presence of 500-times excess competitor DNA fragment harboring NF-IL2 binding site, suggesting indirect binding of NF-IL6 to the Enh1 sequence. These results indicate that IL-6 increased the enhancer activity of HBV Enh1 through signal transduction pathways, indirectly involving NF-IL6, and may control HBV X expression and viral replication in HBV infected liver.

A rapid drug susceptibility test for Mycobacterium tuberculosis using the hybridization protection assay

The conventional drug susceptibility tests for Mycobacterium tuberculosis are time-consuming and the results are available only after 2-4 weeks. We have recently reported a new, simple and fast M. tuberculosis drug susceptibility test, using the hybridization protection assay (HPA), that allows the detection of isoniazid- or rifampicin-resistant strains of M. tuberculosis within 24 h of incubation. In the present study, the scope of application of our new test was extended to another two first-line antimycobacterial agents, namely ethambutol and streptomycin, and a quinolone antimicrobial agent, ciprofloxacin. The ethambutol-, streptomycin- and ciprofloxacin-resistance characteristics of M. tuberculosis were also delineated within 72 h of incubation with or without the drug. The results of our novel and rapid drug susceptibility test for M. tuberculosis were not only comparable to those determined by the conventional method, but became available within a few days of incubation. Our results also suggest that the drug susceptibility test using HPA might also be useful for detecting organisms resistant to antimicrobial agents other than antimycobacterials.

Rapid prediction of rifampin susceptibility of Mycobacterium tuberculosis

We evaluated the relationship between rifampin (RIF) susceptiblility and amino acid substitution in rpoB gene of Mycobacterium tuberculosis and the usefulness of rpoB gene sequencing in the rapid prediction of RIF susceptibility of M. tuberculosis in clinical specimens. A total of 76 genetic alterations in the 69 bp core region of rpoB gene were detected in 74 of 130 M. tuberculosis strains. Examination of the correlation between the minimum inhibitory concentrations (MICs) of RIF and amino acid substitutions in the 69 bp core region of rpoB gene revealed that all 43 strains containing amino acid substitution with Leu or Trp in codon 531 showed RIF-resistant phenotypes, with MICs > or = 64 microg/ml. In contrast, a variable level of RIF susceptibility was observed among strains containing amino acid substitutions in either codon 516 or codon 526. In the clinical study, we tested 26 sputum samples, two gastric lavages, and one synovial fluid sample obtained from patients with tuberculosis. The RIF susceptibility predicted by direct rpoB sequencing was satisfactorily compatible with the results of the RIF-susceptibility test and the MICs of RIF against isolated organisms. Our results suggest that rpoB gene sequencing is useful for the detection of M. tuberculosis in clinical samples as well as the rapid prediction of RIF susceptibility of these strains.