Glutathione homeostasis in alveolar epithelial cells in vitro and lung in vivo under oxidative stress

We studied the acute effects of cigarette smoke condensate (CSC), H2O2, and tumor necrosis factor (TNF)-alpha on the glutathione (GSH) redox system in a human type II epithelial cell line (A549) in vitro. CSC, in vitro and in vivo after intratracheal instillation of CSC in the rat, produced a depletion of intracellular soluble GSH, concomitant with GSH-conjugate formation, without significant elevation of oxidized GSH (GSSG), protein-GSH mixed disulfides (PrSSG), nor any GSH efflux from the cells. By contrast, H2O2 (500 microM) after 5-min exposure to A549 cells caused significant depletion of intracellular GSH associated with an efflux of GSSG and a significant increase in the formation of PrSSG. TNF-alpha, in concentrations of 100 U/ml and 1,000 U/ml, produced a significant depletion of GSH in A549 cells after 4- and 24-h exposure, with an associated elevation of GSSG. The activities of glutathione peroxidase, gamma-glutamylcysteine synthetase, and glucose-6-phosphate dehydrogenase were significantly decreased in epithelial cells and in rat lungs after CSC exposure, without change in glutathione S-transferase and glutathione reductase activities. By contrast, H2O2 and TNF-alpha did not alter these enzyme activities in epithelial cells. Thus GSH depletion and alteration in enzyme activities in alveolar epithelial cells by CSC, H2O2, and TNF-alpha occur by different mechanisms.

On modeling the vibrational spectra of 14-s-cis retinal conformers in bacteriorhodopsin

The vibrational properties of 13-cis, 14-s-trans and 13-cis, 14-s-cis protonated retinal Schiff base model compounds are explored with MNDO calculations. In particular, the effect of isomerization about the C14-C15 single bond on the vibrational properties of the deuterium in-plane rocking vibrations has been examined. Our MNDO calculations, using a variety of lysine models, lysine conformations and Schiff base charge environments, demonstrate that the C14-D and C15-D in-plane rocking vibrations in the 14,15-dideuterio retinal protonated Schiff base are strongly coupled in 13-cis, 14-s-cis molecules producing a splitting of ca. 80 cm-1 between the symmetric and antisymmetric rocking mode combinations but that these modes are only weakly coupled in 14-s-trans molecules. This analysis demonstrates that the 14,15-dideuterio labeling method developed earlier for determining C14-C15 conformation (S.P.A. Fodor, W. T. Pollard, R. Gebhard, E. M. M. van den Berg, J. Lugtenburg and R. A. Mathies, Proc. Natl. Acad. Sci. USA, 85, (1988) 2156-2160) is valid, and hence that the structure of the retinal chromophore in bacteriorhodopsin's L550 intermediate is 13-cis, 14-s-trans. The reasons for the misleading conclusions derived from MNDO calculations performed earlier by Schulten and Tavan are discussed.

Expressions of preproenkephalin mRNA during electroacupuncture analgesia enhanced by fenfluramine

AIM

To study the changes of preproenkephalin (PPE) mRNA in rat brain in response to electroacupuncture (EA) combined with fenfluramine (Fen), a releaser of 5-HT.

METHODS

In situ hybridization histochemistry technique was used to observe the expression of PPE mRNA in rat brain during EA analgesia potentiated by Fen.

RESULTS

The greatest relative increase of PPE mRNA was seen in lumbar spinal cord (laminae I & II), nucleus raphe magnus, dorsal raphe nucleus, periaqueductal gray, interpeduncular nucleus, preoptic lateral area, amygdala nucleus and caudate-putamen (P < 0.01, vs NS + EA). Moderate increases were found in lateral septal, preoptic medial area, hypothalamus ventromedial nucleus, lumbar spinal laminae III & IV (P < 0.05, vs NS + EA). Thalamus showed no statistical significant change in PPE mRNA.

CONCLUSION

The enhancing of PPE mRNA in relative brain nuclei is involved in potentiating action of Fen on EA.

Effect of morphine on interleukin-1 and tumor necrosis factor alpha production from mouse peritoneal macrophages in vitro

AIM

To study the influence of morphine on lymphokine production from mouse peritoneal macrophages (PM phi).

METHODS

The productions of interleukin-1 (IL-1) and tumor necrosis factor (TNF-alpha) from PM phi under various concentrations of morphine with or without naloxone were measured by testing thymocyte proliferation and L929 cell lysis in vitro.

RESULTS

Both morphine (1 x 10(-8) - 1 x 10(-3) mol L-1) and naloxone (50 mumol L-1) inhibited IL-1 production from mouse PM phi primed by sodium thioglycolate. Naloxone did not block the inhibitory effect of morphine. TNF-alpha production from PM phi was inhibited by only high concentration (1 mmol L-1) of morphine which was not blocked by naloxone.

CONCLUSION

Morphine had a direct inhibitory effect on PM phi, which was not mediated by opioid receptor of PM phi.

Photostationary state compositions of retinal and related compounds included in beta-lactoglobulin. Effects of protein host on isomer distribution of polyene substrates

The UV-visible absorption spectra and photostationary state compositions of retinal (or the related C-18 ketone, 3-dehydroretinal and the C-22 aldehyde) imbedded in the binding cavity of beta-lactoglobulin (BLG) are consistent with the view that the carbonyl group of these polyenes are hydrogen-bonded with the protein host, most likely with the lone protonated lysine residue in the binding pocket. Patterns of variation in photochemical behavior of the imbedded chromophore versus that in solution are discussed in terms of possible specific protein-substrate interactions. The results are also compared with that of the methyl ether of retinol where similar hydrogen bonding is not possible.

The role of tumor necrosis factor in increased airspace epithelial permeability in acute lung inflammation

Increased airspace epithelial permeability is an early event in lung inflammation and injury. In this study, we have developed a rat model to study the mechanisms of the epithelial permeability to 125iodine-labeled bovine serum albumin (125I-BSA), instilled intratracheally during acute lung inflammation. Epithelial permeability was measured as the percentage of instilled 125I-BSA appearing in the blood. The increase in epithelial permeability induced by intratracheal instillation of heat-killed Corynebacterium parvum produced a peak influx of neutrophils into the bronchoalveolar space at 16 h, which occurred after the peak increase in epithelial permeability (8 h). The increased epithelial permeability induced by C. parvum did not appear to be protease- or oxidant-mediated. Depletion of peripheral blood neutrophils was achieved by an intravenous injection of anti-neutrophil polyclonal antibody. The consequent profound reduction in neutrophil and macrophage influx into the airspaces 8 h after instillation of C. parvum reduced the epithelial permeability to control values. Bronchoalveolar lavage (BAL) leukocytes from rats 8 h, but not 16 h, after treatment with C. parvum caused a modest increase in epithelial permeability when re-instilled intratracheally into control rat lungs. Separation of the leukocytes before re-instillation indicated that macrophages rather than neutrophils were predominantly responsible for the increased epithelial permeability. The presence of dramatically increased levels of tumor necrosis factor (TNF) in BAL 8 h in contrast to a slight increase in BAL 16 h after C. parvum, the release of TNF from 8 h macrophages, the increased epithelial permeability induced by TNF in epithelial monolayers in vitro, and the inhibition of C. parvum-induced epithelial permeability by TNF antibody support the premise that TNF is a major player in the increased epithelial permeability that occurs during C. parvum-induced acute alveolitis.

Anti-leukocyte function-1 antibody treatment prevents the rejection of intraocular regressor tumors and their metastases

The role of the cell adhesion molecules, LFA-1 and ICAM-1, in intraocular tumor rejection was examined using four different syngeneic intraocular regressor tumors and four different inbred mouse strains. All four tumors undergo T cell-dependent immune rejection in the syngeneic host. Two of the tumors, D5.1G4 melanoma and P91 mastocytoma, undergo rejection by a cytotoxic T lymphocyte-like immune process. The other two tumors, UV5C25 fibrosarcoma and 124E2 melanoma, are rejected by a process that appears to be mediated by delayed-type hypersensitivity. Systemic administration of anti-LFA-1 prevented the rejection of all four categories of tumors. By contrast, similar in vivo treatment with anti-ICAM-1 antibody did not inhibit tumor rejection. The effect of anti-LFA-1 and anti-ICAM-1 antibody treatment on the rejection of metastases arising from intraocular P91 tumors was also examined and found to be highly dependent upon normal LFA-1 function since antibody treatment with anti-LFA-1 prevented the rejection of metastases. Treatment with anti-ICAM-1 antibody alone had no appreciable effect on the rejection of metastases. The results from this study indicate that the expression and function of LFA-1 is crucial for the generation of immune responses to tumor antigens originating within the eye and the expression of tumor immunity within the eye and at distant sites.

Recurrent ischemia in the canine heart causes recurrent bursts of free radical production that have a cumulative effect on contractile function. A pathophysiological basis for chronic myocardial "stunning"

Open-chest dogs (total number used, 117) underwent 10 5-min coronary occlusions (O) interspersed with 10 min of reperfusion (R). When systolic thickening fraction was measured 9 min after each R, the first O-R cycle was found to cause the largest decrement, with only a slight additional loss during the next four cycles and no further loss during the last five cycles (group IV), suggesting that the first few episodes of ischemia preconditioned the myocardium against the stunning induced by the last five episodes. However, different results were obtained when the total deficit of wall thickening during the final 4-h R interval was measured. The total deficit was similar after one and three 5-min O (groups V and VI, respectively), indicating that the first ischemic episode did precondition against the next two episodes; however, it was approximately 2.5-fold greater after 10 O (group IV) than after 3, indicating that the first 3 episodes failed to precondition against the next 7. Thus, at some point between the 4th and 10th O, the preconditioning effect was lost and recurrent ischemic episodes started to have a cumulative effect. Measurements of free radicals with alpha-phenyl N-tert-butyl nitrone (PBN) demonstrated a burst of free radical generation immediately after the 1st, 5th, and 10th R (group VIII). The total cumulative release of PBN adducts during the initial 5 min of reflow was 58% less after the 5th R than after the 1st (P < 0.05) but did not differ significantly between the 1st and 10th R. When administered throughout the 10 O-R cycles, the .OH scavenger mercaptopropionyl glycine significantly enhanced the recovery of function (group I) and markedly suppressed the formation of free radicals (group VII). However, the beneficial effects of mercaptopropionyl glycine were completely, or largely, lost if the drug was discontinued after the first five (group II) or eight (group III) O-R cycles, respectively, implying that (a) the oxidative stress associated with the last five, or even two, cycles was sufficient to cause severe postischemic dysfunction, and (b) the cumulative injury caused by repetitive ischemic episodes is mediated by recurrent oxidative stress. This study provides direct in vivo evidence that oxygen radicals play an important role in the pathogenesis of myocardial stunning after repetitive ischemia, and implicates .OH as a primary culprit. Taken together, the data indicate that recurrent brief ischemic episodes result in recurrent bouts of oxyradical-mediated injury that have a cumulative effect on contractility, a situation that could lead to protracted or even chronic myocardial stunning.

Early appearance of T cell receptor alpha beta + CD4- CD8- T cells with a skewed variable region repertoire after infection with Listeria monocytogenes

We found that the number of T cell receptor (TCR) alpha beta + CD4- CD8- T cells increased in the peritoneal cavity on day 5 after an intraperitoneal infection with Listeria monocytogenes strain EGD together with TCR gamma delta + CD4- CD8- T cells. Thereafter, the TCR alpha beta + CD4- CD8- T cells decreased to a normal level by day 14. The TCR alpha beta + CD4- CD8- T cells showed an activated T cell phenotype (L-selectin CD44 +) and expressed CD45/B220 and interleukin-2 receptor beta, but did not express heat stable antigen, which is expressed by the immature CD4- CD8- thymocytes. Furthermore, 20-30% of the TCR alpha beta + CD4- CD8- T cells expressed the NK1.1 natural killer cell marker. Analysis of the TCR V region repertoire of the TCR alpha beta + CD4- CD8- T cells induced by L. monocytogenes infection showed that more than 80% of the TCR alpha beta + CD4- CD8- T cells expressed TCR V beta 8 detected by anti-TCR V beta 8.1 and 8.2 mAb, and a reverse transcription-polymerase chain reaction analysis of V alpha 14 relative to V alpha 11 expression revealed that the TCR alpha beta + CD4- CD8- T cells expressed a higher level of V alpha 14, which was reported to be preferentially expressed by TCR alpha beta + CD4- CD8- thymocytes rather than conventional CD4+ T cells. The TCR alpha beta + CD4- CD8-T cells showed a proliferative response to anti-TCR alpha beta mAb stimulation. In contrast, they showed no response to stimulation with either Listeria antigen or 65-kDa heat shock protein of Mycobacterium bovis, which do stimulate the Listeria-specific TCR alpha beta + CD4- CD8- T cells and the Listeria-induced TCR gamma delta + T cells, respectively. These results suggest that the TCR alpha beta + CD4- CD8- T cells may recognize a restricted set of self antigens induced by L. monocytogenes infection, and that they contribute to host protection at an early stage of infection.

Binding sites of mu receptor increased when acupuncture analgesia was enhanced by droperidol: an autoradiographic study

AIM

To study if mu receptor participates in the process of potentiation of droperidol (Dro) on acupuncture analgesia (AA).

METHODS

Autoradiographic technic was used. Ohmefentanyl, a highly selective ligand of mu receptors, was used in radio-receptor binding assay in Sprague-Dawley rat brain sections.

RESULTS

The binding sites of [beta-3H, p-benzoyl-3H]ohmefentanyl were increased greatly in many nuclei of rat brain after AA, and were further increased when AA was enhanced by Dro. Higher increase was seen in caudate nucleus, accumbens, periaqueductal gray (PAG), interpeduncular nucleus, amygdala (P < 0.01 vs rats treated with electroacupuncture alone); moderate increase was noted in thalamus, lateral area of hypothalamus, spinal dorsal horn (P < 0.01 or 0.05); slight increase appeared in septum, preoptic area, hippocampus, substantia nigra (P < 0.05).

CONCLUSION

Mu opioid receptors mediated the Dro-induced enhancement of AA.

Effects of morphine and naloxone on proliferation of lymphocytes in vitro

AIM

To study the effects of morphine on different lymphocytes and the influence of naloxone.

METHODS

The proliferation rates of unmature, resting, and activated T-lymphocytes and B-lymphocytes were determined under various concentrations of morphine with or without naloxone in vitro.

RESULTS

Morphine 1 x 10(-10)-1 x 10(-6) mol L-1 enhanced concanavalin A (Con A)-induced splenic T-cell proliferation, and 1 mumol L-1 enhanced lipopolysaccharide (LPS)-induced splenic B-cell proliferation. Naloxone, which per se enhanced the T-cell proliferation, blocked the enhancing effects of morphine. Morphine (1 x 10(-10)-1 x 10(-5) mol L-1) had no influence on the proliferation of resting splenocytes and Con A-induced thymus cells. Morphine 1 mmol L-1 inhibited the proliferation of resting, LPS-induced splenocytes, and Con A-induced splenic and thymus cells. These inhibiting effects were not blocked by naloxone (50 mumol L-1).

CONCLUSION

Stimulating effect of morphine on activated T- and B-cells were mediated by opioid receptors and different opioid receptors existed during the differentiation and activation of lymphocytes. The inhibitory effects of morphine (1 mmol L-1) were not mediated by opioid receptors.

Brain- and intestine-specific variants of reovirus serotype 3 strain dearing are selected during chronic infection of severe combined immunodeficient mice

Mutants of mammalian reoviruses, enteric double-stranded-RNA-containing viruses that spread systemically after primary replication in intestinal tissue, have been extensively studied as models of viral pathogenesis. While reovirus serotype 3 strain Dearing (T3D) causes acute encephalitis in newborn mice, adult severe combined immunodeficient (SCID) mice develop chronic infection with T3D, with some mice living more than 100 days after infection (B. L. Haller, M. L. Barkon, G. P. Vogler, and H. W. Virgin IV, J. Virol. 69:357-364, 1995). To determine whether organ-specific reovirus variants are selected during chronic infection, we characterized the pathogenetic properties of two variants of T3D isolated 87 days after intraperitoneal infection of adult SCID mice. A brain-specific variant (T3DvBr) (i) grew to a higher titer than T3D in SCID mouse brain (but not intestine) after intraperitoneal inoculation, (ii) killed adult SCID mice faster than T3D, and (iii) grew well in neonatal NIH Swiss [NIH(s)] mouse brain tissue after intramuscular but not peroral inoculation. An intestine-specific variant (T3DvInt) (i) grew to a higher titer than T3D in SCID mouse intestine (but not brain) after intraperitoneal inoculation, (ii) killed SCID mice with kinetics equivalent to those of T3D, (iii) was much less virulent than T3D in neonatal NIH(s) mice, (iv) grew better than T3D in intestines after intramuscular or peroral inoculation into neonatal NIH(s) mice, and (v) grew poorly in brain tissue of neonatal NIH(s) mice after intramuscular inoculation. During prolonged infection of SCID mice, organ-specific variants of T3D, which are more efficient than wild-type T3D at one specific stage in reovirus pathogenesis, are selected.

Methionine-enkephalin augments interleukin-6 production and gene expression

AIM

To study the effect of methionine-enkephalin (met-enk) on the production and gene expression of interleukin-6 (IL-6) both in vivo and in vitro.

METHODS

IL-6 was assayed using its dependent cell line MH60.BSF2 and measured by MTT spectrophotometry. IL-6 gene expression was proceeded by RNA isolation and hybridization with IL-6 cDNA.

RESULTS

Met-enk stimulated IL-6 mRNA expression and increased its stability. Met-enk 0.1 and 1 mg.kg-1 ip for 6 d enhanced serum IL-6 levels.

CONCLUSION

An up-regulation of IL-6 by met-enk was mediated through an increase in transcriptional activity and stability of IL-6 mRNA.

Preproenkephalin mRNA enhanced by combination of droperidol with electroacupuncture

AIM

To study the expression of preproenkephalin (PPE) mRNA following electroacupuncture (EA) combined with droperidol (Dro), an antagonist of dopamine receptors.

METHOD

The brains of Sprague-Dawley rats were sectioned after combination of EA with Dro and nonradioactive in situ hybridization histochemistry (ISHH) technic was used.

RESULTS

Ten hours after EA, the expression of PPE mRNA was enhanced; when EA was combined with Dro, the expression of PPE mRNA was further enhanced in many pain-modulation-related nuclei, such as caudate-putamen, accumbens, septal nucleus, diagonal band nucleus, amygdala, hypothalamus, periaqueductal gray (PAG), interpeduncular nucleus, substantia nigra, and the dorsal horn of spinal cord (layer I-II and III-IV).

CONCLUSION

Dro promoted EA's action on the PPE mRNA expression, which underlie the mechanisms of Dro potentiation on acupuncture analgesia.

Effects of anisodamine against myocardial ischemia-reperfused injuries and antilipid peroxidation

AIM

Anisodamine (Ani), an alkaloid first isolated in China. To study the relationship between the protective effects of Ani on myocardial cells of reperfused injuries and the antilipid peroxidation.

METHODS

Coronary ligation for 15-min followed by 10 min reperfusion was performed in anesthetized rats.

RESULTS

Ani 1, 3, 5 mg.kg-1 i.v. 1 min prior to reperfusion could dose-dependently lower the release of creatine kinase (282 +/- 29, 252 +/- 53, 226 +/- 50), counteract the increase of malondialdehyde content (3.3 +/- 1.3, 3.2 +/- 1.6, 3.1 +/- 1.2) in the reperfused myocardium and preserve the SOD activity (41 +/- 7, 46 +/- 8, 55 +/- 8). Ani completely abolished the drop in the contents of principal unsaturated fatty acids (oleic, linoleic, and arachidonic acids) of the membrane lipids in the reperfused myocardium. SOD 75 U.kg-1 i.v. 1 min prior to reperfusion exerted similar effects like Ani 3 mg.kg-1.

CONCLUSION

It is suggested that the antilipid peroxidative effect of Ani may contribute to its protection against reperfusion-induced myocardial injuries.

Retinoic acid antagonizes basal as well as coal tar and glucocorticoid-induced cytochrome P4501A1 expression in human skin

Cytochrome P4501A1 is known to be expressed in skin and thus has been implicated in the pathogenesis of skin cancer due to certain environmental carcinogens. Retinoic acid (RA) has been used in chemoprevention of certain skin and other epithelial cancers. Therefore, we used Northern and Western analysis to determine the effect of externally applied RA on basal P4501A1 expression. RA reduced basal levels of P4501A1 mRNA and protein by 68 (n = 14, P = 0.005) and 75% (n = 7, P = 0.04) respectively. RA application also reduced basal levels of P4501A2 (another P4501A1 subfamily member) mRNA by 93% (n = 7, P = 0.001) as determined by reverse transcription-polymerase chain reaction. Interestingly, P4501A1 mRNA expression induced by coal tar or glucocorticoid (clobetasol) was reduced 46 (n = 10, P = 0.003) and 69% (n = 5, P < 0.05) respectively by RA co-application. Downregulation of basal P4501A1 expression and antagonism of coal tar mediated P4501A1 induction by RA may be a mechanism involved in chemo-prevention of skin and other epithelial cancer by RA.

Immunomodulating effects of morphine microinjected into periaqueductal gray

AIM

To study the effects of morphine on immune system through rat brain periaqueductal gray (PAG).

METHODS

Three hours after microinjection of morphine through the implanted steel tubes to PAG, splenic cytokines interleukin 2 (IL-2), interleukin 6 (IL-6), tumor necrosis factor (TNF), and natural killer cells (NK) activity were measured.

RESULTS

Microinjection of morphine (0.5 microL, 3672 ng) into PAG region had no influence on IL-6 and TNF-alpha (production of splenic macrophages, suppressed the natural killer cell (NK) activity and enhanced T-lymphocyte functions, including concanavalin A (Con A)-induced T-cell proliferation, IL-2 and TNF-beta production. Both the suppressive and stimulating actions were blocked by PAG preinjection of the mu opioid receptor antagonist naloxone (0.5 microL, 1 microgram), which alone showed the contrary effect to morphine.

CONCLUSION

Morphine affected immunofunctions through opioid receptors in PAG, and the influences on various immunocompetent cells were different.

[Tyr-D-Ala-Gly-Phe-D-Leu (DADL) solid-phase synthesis and its effects on immune function]

DADL, a delta-receptor selective enkephalin analogue, was prepared with the technique of solid-phase peptide synthesis. It was found to stimulate directly the proliferation of mouse splenic lymphocytes dose-dependently. However, synergistic effect of DADL at different concentrations with ConA and LPS were not found. In addition, TNF-alpha production was increased by ip DADL (1.0 mg.kg-1 x 6 d) in mice and the production of LPS-induced TNF-alpha in mouse peritoneal macrophages was enhanced after DADL was added in vitro. These results suggest that DADL, like enkephalins, exerts some immunoregulatory activities.

[Electron microscopic observation of the denervated flap reinnervation after implantation of sensory nerve]

Flap reinnervation was studied by electron microscopy in the rabbit cervico-shoulder flap with great auricular nerve implanted. After transferring the flap to the dorsal defect of the rabbit's ear and division of its pedicle, the original nerve fibers of the flap underwent a degenerative process which would persist over 2 months. The great auricular nerve implanted into the flap regenerated axons by entering into old endoneurial rube of the flap and sprouting. The development process of the regenerating nerves showed that the unmyelinated fibers appeared first in the 2nd month, and the myelinated ones in the 4th month. The regenerating nerve fibers had often accompanied by blood vessels.

[Detection of Mycobacterium tuberculosis using a nested-primer gene amplification assay]

A nested-primer gene amplification assay (NPGAA) was established by using two pairs of primers, an outside pair of primers and an inside pair of primers, sequences of which were from M. tuberculosis(Mtb) gro EL genes. The outside pair of primers should amplify a 576-bp piece of the Mtb gro EL gene that contains sites for the inside pair of primers, which should amplify a 344-bp piece. The results shows NPGAA'S detectable limitation was 1 organism/ml and no amplification products were produced from DNAs of other mycobacterium species tested in this study. For detecting Mtb, the entire NPGAA, from sample preparation to data analysis, can be completed within 6-8 hours. When identifying AFB cultures isolated from lesions of skin diseases, the same positive size patterns were obtained.

Dominant negative analogs of NF-YA

NF-Y is a highly conserved heteromeric CCAAT-binding transcription factor involved in the function of several promoters. The NF-YA subunit contains a domain of high homology to yeast HAP2, which we show to be necessary and sufficient to mediate interactions with the NF-YB subunit and with DNA. Using protein affinity columns derivatized with amino acid substitution mutants, we further dissect this region into two functionally separable subdomains. The subunit association function resides in a 21-amino acid stretch, which is almost perfectly conserved among different species, while interaction with DNA resides in another short segment. We also show that DNA-binding mutants act as dominant repressors of NF-Y-DNA complex formation and of NF-Y-dependent transcription.

An investigation of the role of glutathione in increased epithelial permeability induced by cigarette smoke in vivo and in vitro

Airspace epithelial permeability is known to increase in cigarette smokers. To study the role of the antioxidant reduced glutathione (GSH) in this phenomenon, we used an in vitro model of the epithelial permeability of a monolayer of human type II alveolar epithelial cells (A549 cell line). Both whole (WSC) and vapor (VSC) smoke condensates induced a recoverable, concentration-dependent increase in epithelial permeability to 125iodine-labeled bovine serum albumin (125IBSA), associated with a profound fall in intracellular GSH. Buthionine sulfoximine (BSO), a GSH synthesis inhibitor, decreased GSH levels in A549 epithelial cells, significantly increased A549 epithelial cell permeability, and enhanced both WSC and VSC-induced A549 epithelial cell permeability. Co-culturing epithelial cells and GSH (500 microM) reduced WSC-induced, but not VSC-induced A549 epithelial cell permeability. Increasing intracellular GSH also ameliorated the smoke-induced increased epithelial permeability. Concentrations of cigarette smoke condensate of < 20% increased A549 epithelial cell permeability without associated cell detachment and lysis, which was also the case with BSO-induced increased epithelial permeability. WSC and VSC, instilled intratracheally, significantly increased rat lung epithelial permeability to 125IBSA, 6 h postinstillation, associated with a significant recruitment of neutrophils into the airspaces. This was associated with a small increase in GSH in the lung tissue of VSC-treated rats. However, both WSC and VSC markedly reduced GSH in bronchoalveolar lavage (BAL) fluid. Reduction in lung GSH to 95% but not to 68% of control values by BSO increased lung epithelial permeability in vivo. However, there was no additive effect on epithelial permeability of WSC and BSO.(ABSTRACT TRUNCATED AT 250 WORDS)

Type-specific immune response to human T cell lymphotropic virus (HTLV) type I and type II infections in Nigeria

Type-specific antibody responses to human T cell lymphotropic virus type I (HTLV-I) and type II (HTLV-II) were studied in blood samples collected from 25 different locations in Nigeria between 1985 and 1991 and stored at the University College Hospital in Ibadan. A total of 4,153 sera were collected from participants in the National Immunity Survey of Viral Infections (n = 1,640), patients with tuberculosis (TB) (n = 140), patients with sexually transmitted diseases (STDs) (n = 876), patients with other medical conditions (n = 1,285), female prostitutes (n = 60), and health care workers (n = 152). The overall seroprevalence of HTLV was 5.6%, with similar rates among males and females. Using enzyme immunoassays that differentiated between antibodies to the two viruses, the seroprevalence rates were 2.5% for HTLV-I and 1.9% for HTLV-II, with an additional 1.2% of the samples dually reactive for both HTLV-I and HTLV-II. The seroprevalence rates for HTLV were low among children (0.8%) and adolescents (1.7%), with substantially higher rates among adults (range 5.0-7.4%). Age-specific patterns among adults appears to differ for HTLV-I and HTLV-II, with HTLV-I rates peaking above age 50 and HTLV-II rates peaking below age 50. The highest overall HTLV prevalence rates were observed for STD patients (16.3%), followed by female prostitutes (8.3%), TB patients (6.4%), health care workers (3.3%), patients with other medical conditions (3.2%), and immunity survey participants (1.8%).(ABSTRACT TRUNCATED AT 250 WORDS)