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Sex differences in transport of the organic anion (OA) substrate p-aminohippurate (PAH) and the organic cation (OC) substrate tetraethylammonium (TEA) have been recognized for some time. In the rat kidney, androgens up-regulate and estrogens down-regulate PAH and TEA transport, which correlate with similar changes in mRNA and protein expression for the renal basolateral membrane transporters organic anion transporter (Oat) 1 and organic cation transporter (Oct) 2. However, these sex differences are not readily demonstrated in other species. The present study characterizes the kinetics of basolateral membrane PAH, estrone sulfate (ES), and TEA uptake in renal proximal tubule (RPT) suspensions isolated from female and male rabbits to compare functional expression of transport with mRNA and protein expression for rbOat1, rbOat3, and rbOct2. Although rbOat1-rbOat3 mRNA expression exhibited developmental differences, no sex differences in mRNA levels were observed. Oat1 and Oat3 protein expression in RPT suspensions also was similar between adult female and male rabbits. In contrast, rbOct1 and rbOct2 mRNA levels did not show developmental differences, but rbOct2 mRNA expression was greater in adult male than female rabbits. However, the sex difference in rbOct2 mRNA level did not translate to rbOct2 protein expression. Importantly, functional expression of Oat1, Oat3, and Oct2 transport as measured by kinetics (J(max) and K(t)) of PAH, ES, and TEA uptake was similar between adult male and female rabbits, and correlated with rbOat1, rbOat3, and rbOct2 protein expression. Thus, unlike rodents, rabbit renal OA and OC transport does not exhibit sex differences, pointing to the need for caution in extrapolating transport-related sex differences between species.

Questions about possible adverse health effects from exposures to uranium have arisen as a result of uranium mining, residual mine tailings and use of depleted uranium in the military. The purpose of the current study was to measure the toxicity of depleted uranium as uranyl acetate (UA) in mammalian cells. The activity of UA in the parental CHO AA8 line was compared with that in the XRCC1-deficient CHO EM9 line. Cytotoxicity was measured by clonogenic survival. A dose of 200 microM UA over 24 h produced 3.1-fold greater cell death in the CHO EM9 than the CHO AA8 line, and a dose of 300 microM was 1.7-fold more cytotoxic. Mutagenicity at the hypoxanthine (guanine) phosphoribosyltransferase (hprt) locus was measured by selection with 6-thioguanine. A dose of 200 microM UA produced approximately 5-fold higher averaged induced mutant frequency in the CHO EM9 line relative to the CHO AA8 line. The generation of DNA strand breaks was measured by the alkaline comet assay at 40 min and 24 h exposures. DNA strand breaks were detected in both lines; however a dose response may have been masked by U-DNA adducts or crosslinks. Uranium-DNA adducts were measured by inductively coupled plasma optical emission spectroscopy (ICP-OES) at 24 and 48 h exposures. A maximum adduct level of 8 U atoms/10(3) DNA-P for the 300 microM dose was found in the EM9 line after 48 h. This is the first report of the formation of uranium-DNA adducts and mutations in mammalian cells after direct exposure to a depleted uranium compound. Data suggest that uranium could be chemically genotoxic and mutagenic through the formation of strand breaks and covalent U-DNA adducts. Thus the health risks for uranium exposure could go beyond those for radiation exposure.

Major compounds of several commonly used botanicals, including turmeric, have been purported to have anti-inflammatory actions. In order to test the anti-inflammatory activity of compounds isolated from rhizomes of Curcuma longa L. (Zingiberaceae), we have established an in vitro test system. HL-60 cells were differentiated and exposed to lipopolysaccharide (LPS) from Escherichia coli (1 microg/ml) in the presence or absence of botanical compounds for 24 h. Supernatants were collected and analyzed for the production of tumor necrosis factor alpha (TNF-alpha) and prostaglandin E2 (PGE2) using standard ELISA assays. Water-soluble extracts were not cytotoxic and did not exhibit biological activity. Organic extracts of turmeric were cytotoxic only at concentrations above 50 microg/ml. Crude organic extracts of turmeric were capable of inhibiting LPS-induced TNF-alpha (IC50 value = 15.2 microg/ml) and PGE2 (IC50 value = 0.92 microg/ml) production. Purified curcumin was more active than either demethoxy- or bisdemethoxycurcumin. Fractions and subfractions of turmeric extracts collected via preparative HPLC had differing biological activity, ranging from no activity to IC50 values of < 1 microg/ml. For some fractions, subfractionation resulted in a loss of activity, indicating interaction of the compounds within the fraction to produce an anti-inflammatory effect. A combination of several of the fractions that contain the turmeric oils was more effective than the curcuminoids at inhibiting PGE2. While curcumin inhibited COX-2 expression, turmeric oils had no effect on levels of COX-2 mRNA.

Using techniques previously employed to identify ginger constituents in fresh organically grown Hawaiian white and yellow ginger varieties, partially purified fractions derived from the silica gel column chromatography and HPLC of a methylene chloride extract of commercially processed dry ginger, Zingiber officinale Roscoe, Zingiberaceae, which demonstrated remarkable anti-inflammatory activity, were investigated by gas chromatography-mass spectrometry. In all, 115 compounds were identified, 88 with retention times (R(t)) >21 min and 27 with <21 min. Of those 88 compounds, 45 were previously reported by us from fresh ginger, 12 are cited elsewhere in the literature and the rest (31) are new: methyl [8]-paradol, methyl [6]-isogingerol, methyl [4]-shogaol, [6]-isoshogaol, two 6-hydroxy-[n]-shogaols (n=8 and 10), 6-dehydro-[6]-gingerol, three 5-methoxy-[n]-gingerols (n=4, 8 and 10), 3-acetoxy-[4]-gingerdiol, 5-acetoxy-[6]-gingerdiol (stereoisomer), diacetoxy-[8]-gingerdiol, methyl diacetoxy-[8]-gingerdiol, 6-(4'-hydroxy-3'-methoxyphenyl)-2-nonyl-2-hydroxytetrahydropyran, 3-acetoxydihydro-[6]-paradol methyl ether, 1-(4'-hydroxy-3'-methoxyphenyl)-2-nonadecen-1-one and its methyl ether derivative, 1,7-bis-(4'-hydroxy-3'-methoxyphenyl)-5-methoxyheptan-3-one, 1,7-bis-(4'-hydroxy-3'-methoxyphenyl)-3-hydroxy-5-acetoxyheptane, acetoxy-3-dihydrodemethoxy-[6]-shogaol, 5-acetoxy-3-deoxy-[6]-gingerol, 1-hydroxy-[6]-paradol, (2E)-geranial acetals of [4]- and [6]-gingerdiols, (2Z)-neral acetal of [6]-gingerdiol, acetaldehyde acetal of [6]-gingerdiol, 1-(4-hydroxy-3-methoxyphenyl)-2,4-dehydro-6-decanone and the cyclic methyl orthoesters of [6]- and [10]-gingerdiols. Of the 27 R(t)<21 min compounds, we had found 5 from fresh ginger, 20 others were found elsewhere in the literature, and two are new: 5-(4'-hydroxy-3'-methoxyphenyl)-pent-2-en-1-al and 5-(4'-hydroxy-3'-methoxyphenyl)-3-hydroxy-1-pentanal. Most of the short R(t) compounds are probably formed by thermal degradation during GC (which mimics cooking) and/or commercial drying. The concentrations of gingerols, the major constituents of fresh ginger, were reduced slightly in dry ginger, while the concentrations of shogaols, the major gingerol dehydration products, increased.

Organic cations (OCs) constitute a diverse array of compounds of physiological, pharmacological, and toxicological importance. Renal secretion of these compounds, which occurs principally along the proximal portion of the nephron, plays a critical role in regulating the concentration of OCs in the plasma and in clearing the body of potentially toxic xenobiotic OCs. Transepithelial OC transport in the kidney involves separate entry and exit steps at the basolateral and luminal aspects of renal tubular cells. It is increasingly apparent that basolateral and luminal OC transport reflects the concerted activity of a suite of separate transport processes arranged in parallel in each pole of proximal tubule cells. Most of the transporters that appear to dominate renal secretion of OCs belong to a single family of transport proteins: the OCT Family. The characterization of their activity, and their localization within distinct regions of the kidney, has permitted development of models describing the molecular and cellular basis of the renal secretion of OCs.

Organic cation transporters are important for the elimination of many drugs and toxins from the body. In the present study, substrate-transporter interactions were investigated in Chinese hamster ovary cells stably transfected with either the human or rabbit orthologs of the principal organic cation transporter in the kidney, OCT2. IC(50) values, ranging from 0.04 muM to >3 mM, for inhibition of [(14)C]tetraethylammonium transport were determined for more than 30 structurally diverse compounds. Although the two OCT orthologs displayed similar IC(50) values for some of these compounds, the majority varied by as much as 20-fold. Marked differences in substrate affinity were also noted when comparing hOCT2 to the closely related homolog hOCT1. These data suggest the molecular determinants of substrate binding differ markedly among both homologous and orthologous OCT transporters. The software package Cerius(2) (Accelrys, San Diego, CA) was used to generate a descriptor-based, two-dimensional, quantitative structure-activity relationship (QSAR) to produce a model relating the affinity of hOCT2 to particular physicochemical features of substrate/inhibitor molecules (r(2) = 0.81). Comparative molecular field analysis (Tripos, St. Louis, MO) was used to generate three-dimensional QSARs describing the structural basis of substrate binding to hOCT2 and rbOCT2 (q(2) = 0.60 and 0.53, respectively, and each with r(2) = 0.97). The quality of the models was assessed by their ability to successfully predict the inhibition of a set of test compounds. The current models enabled prediction of OCT2 affinity and may prove useful in the prediction of unwanted drug interactions at the level of the renal secretory process.

It was shown previously that OAT3 activity was differentially regulated by protein kinases including MAPK, PKA, and PKC. The present study investigated the short-term effect of tyrosine kinase and phosphatidylinositol 3-kinase (PI3K) on OAT3-mediated organic anion transport in S2 segments of renal proximal tubules. Genistein, a tyrosine kinase inhibitor, and wortmannin, a PI3K inhibitor, inhibited transport of estrone sulfate, a prototypic substrate for OAT3, in a dose-dependent manner. Previously, we showed that epidermal growth factor (EGF) stimulated OAT3 activity via the MAPK pathway. In the present study, we investigated whether EGF-stimulated OAT3 activity was dependent on tyrosine kinase and PI3K. We showed that EGF stimulation of OAT3 was reduced by inhibition of tyrosine kinase or PI3K, suggesting that they play a role in the stimulatory process. Inhibitory effects also indicated that tyrosine kinase and PI3K are involved in the MAPK pathway for EGF stimulation of OAT3 in intact renal proximal tubules, with PI3K acting upstream and tyrosine kinase acting downstream of mitogen-activated/extracellular signal-regulated kinase kinase activation.

OCT1 and OCT2 are involved in renal secretion of cationic drugs. Although they have similar selectivity for some substrates (e.g. tetraethylammonium (TEA)), they have distinct selectivities for others (e.g. cimetidine). We postulated that "homolog-specific residues," i.e. the 24 residues that are conserved in OCT1 orthologs as one amino acid and in OCT2 as a different one, influence homolog-specific selectivity and examined the influence on substrate binding of three of these conserved residues that are found in the C-terminal half of the rabbit orthologs of OCT1/2. The N353L and R403I substitutions (OCT2 to OCT1) did not significantly change the properties of OCT2. However, the E447Q replacement shifted substrate selectivity toward an OCT1-like phenotype. Substitution of glutamate with cationic amino acids (E447K and E447R) abolished transport activity, and the E447L mutant displayed markedly reduced transport of TEA and cimetidine while retaining transport of 1-methyl-4-phenylpyridinium. In a novel homology model of the three-dimensional structure of OCT2, Glu(447) was found in a putative docking region within a hydrophilic cleft of the protein. In addition, six residues identified in separate studies as exerting significant effects on OCT binding were also found within the putative cleft region. There was a significant correlation (r(2) = 0.82) between the IC(50) values for inhibition of TEA transport by 14 different compounds and their calculated K(D) values for binding to the model of rabbit OCT2. The results suggest that homology modeling offers an opportunity to direct future site-directed studies of OCT/substrate interaction.

During annual medical monitoring, some firefighters are found to have rates of decline in forced expiratory volume in one second (FEV1) far exceeding their peers. Interleukin-10 (IL-10) suppresses inflammation, and single nucleotide polymorphisms (SNPs) in the IL-10 gene may confer variable susceptibility to more rapid decline in lung function. In 1204 firefighters with at least six annual FEV1 measurements, increased age and greater initial FEV1 were associated with more rapid decline in lung function. DNA collected from 379 of these firefighters was screened for IL-10 SNPs at -1117, -854, 919, 1668, and 1812. A statistically significant difference in decline in lung function was found based on genotyping at the 1668 SNP. Evaluation of gene polymorphisms regulating lung inflammation may help to explain some of the variation in rate of decline in lung function in firefighters.

Gas chromatography in conjunction with mass spectrometry, a technique previously employed to analyze non-volatile pungent components of ginger extracts modified to trimethylsilyl derivatives, was applied successfully for the first time to analyze unmodified partially purified fractions from the dichloromethane extracts of organically grown samples of fresh Chinese white and Japanese yellow varieties of ginger, Zingiber officinale Roscoe (Zingiberaceae). This analysis resulted in the detection of 20 hitherto unknown natural products and 31 compounds previously reported as ginger constituents. These include paradols, dihydroparadols, gingerols, acetyl derivatives of gingerols, shogaols, 3-dihydroshogaols, gingerdiols, mono- and diacetyl derivatives of gingerdiols, 1-dehydrogingerdiones, diarylheptanoids, and methyl ether derivatives of some of these compounds. The thermal degradation of gingerols to gingerone, shogaols, and related compounds was demonstrated. The major constituent in the two varieties was [6]-gingerol, a chemical marker for Z. officinale. Mass spectral fragmentation patterns for all the compounds are described and interpreted. Anti-inflammatory activities of silica gel chromatography fractions were tested using an in vitro PGE2 assay. Most of the fractions containing gingerols and/or gingerol derivatives showed excellent inhibition of LPS-induced PGE2 production.

To characterize the tachykininergic effects in fire smoke (FS)-induced acute respiratory distress syndrome (ARDS), we designed a series of studies in rats. Initially, 20 min of FS inhalation induced a significant increase of substance P (SP) in bronchoalveolar lavage fluid (BALF) at 1 h and persisted for 24 h after insult. Conversely, FS disrupted 51.4, 55.6, 46.3, and 43.0% enzymatic activity of neutral endopeptidase (NEP, a primary hydrolyzing enzyme for SP) 1, 6, 12, and 24 h after insult, respectively. Immunolabeling density of NEP in the airway epithelium largely disappeared 1 h after insult due to acute cell damage and shedding. These changes were also accompanied by extensive influx of albumin and granulocytes/lymphocytes in BALF. Furthermore, levels of BALF SP and tissue NEP activity dose dependently increased and decreased, respectively, following 0, low (10 min), and high (20 min) levels of FS inhalation. However, neither the time-course nor the dose-response study observed a significant change in the highest affinity neurokinin-1 receptor (NK-1R) for SP. Finally, treatment (10 mg/kg im) with SR-140333B, an NK-1R antagonist, significantly prevented 20-min FS-induced hypoxemia and pulmonary edema 24 h after insult. Further examination indicated that SR-140333B (1.0 or 10.0 mg/kg im) fully abolished early (1 h) plasma extravasation following FS. Collectively, these findings suggest that a combination of sustained SP and NEP inactivity induces an exaggerated neurogenic inflammation mediated by NK-1R, which may lead to an uncontrolled influx of protein-rich edema fluid and cells into the alveoli as a consequence of increased vascular permeability.

To examine the hypothesis that Jet Propulsion Fuel (JP-8) inhalation potentiates influenza virus-induced inflammatory responses, we randomly divided female C57BL/6 mice (4-weeks old, weighing approximately 24.6g) into the following groups: air control, JP-8 alone (1023 mg/m(3) of JP-8 for 1h/day for 7 days), A/Hong Kong/8/68 influenza virus (HKV) alone (a 10 microl aliquot of 2000 viral titer in the nasal passages), and a combination of JP-8 with HKV (JP-8 + HKV). The HKV alone group exhibited significantly increased total cell number/granulocyte differential in bronchoalveolar lavage fluid (BALF) compared to controls whereas the JP-8 alone group did not. The JP-8 + HKV group further exacerbated the HKV alone-induced response. However, increases in pulmonary microvascular permeability and pathological alterations in JP-8 + HKV just matched the sum of JP-8 alone- and HKV alone-induced response. Increases in BALF substance P in the JP-8 alone group and BALF leukotriene B4 or total lung compliance in the HKV alone group, respectively were similar to the changes in the JP-8 + HKV group. These findings suggest that changes in the JP-8 + HKV group may be attributed to either JP-8 inhalation or HKV treatment and indicate the different physiological responses to either JP-8 or HKV exposure. Taken together, most of the data did not provide supporting evidence that JP-8 inhalation synergizes influenza virus-induced inflammatory responses.

This brief review is intended to serve as a refresher on the ideas associated with teaching students the physiological basis of the resting membrane potential. The presentation is targeted toward first-year medical students, first-year graduate students, or senior undergraduates. The emphasis is on general concepts associated with generation of the electrical potential difference that exists across the plasma membrane of every animal cell. The intention is to provide students a general view of the quantitative relationship that exists between 1) transmembrane gradients for K(+) and Na(+) and 2) the relative channel-mediated permeability of the membrane to these ions.

Organic cations and anions (OCs and OAs, respectively) constitute an extraordinarily diverse array of compounds of physiological, pharmacological, and toxicological importance. Renal secretion of these compounds, which occurs principally along the proximal portion of the nephron, plays a critical role in regulating their plasma concentrations and in clearing the body of potentially toxic xenobiotics agents. The transepithelial transport involves separate entry and exit steps at the basolateral and luminal aspects of renal tubular cells. It is increasingly apparent that basolateral and luminal OC and OA transport reflects the concerted activity of a suite of separate transport processes arranged in parallel in each pole of proximal tubule cells. The cloning of multiple members of several distinct transport families, the subsequent characterization of their activity, and their subcellular localization within distinct regions of the kidney now allows the development of models describing the molecular basis of the renal secretion of OCs and OAs. This review examines recent work on this issue, with particular emphasis on attempts to integrate information concerning the activity of cloned transporters in heterologous expression systems to that observed in studies of physiologically intact renal systems.

Vinyl acetate is a synthetic organic ester that has been shown to produce nasal tumors in rats following exposure to 600 ppm in air. The proposed mechanism of action involves the metabolism of vinyl acetate by carboxylesterases and the production of protons leading to cellular acidification. While vinyl acetate-induced decreases in intracellular pH (pHi) have been demonstrated in rat hepatocytes, comparable data from nasal epithelial cells do not exist. Using an in vitro assay system, we have determined the effects of vinyl acetate exposure on pHi in respiratory and olfactory nasal epithelial cells from rats. The respiratory and olfactory epithelial cells were isolated from dissected maxillo- and ethmoturbinates by enzyme digestion. The cells were plated; loaded with the pH-sensitive dye, carboxyseminaphthorhodafluor-1 (SNARF-1); and observed using confocal microscopy. Individual cellular analysis demonstrated that both respiratory and olfactory epithelial cells responded to vinyl acetate exposures with a dose-dependent decrease in pHi. Changes occurred at 100 microM but reached a plateau above 250 microM. Maximal decreases in pHi were 0.3 pH unit in respiratory epithelial cells. While pHi values were normally distributed for the respiratory epithelial cells, the olfactory epithelial cells demonstrated a bimodal distribution, indicating at least two populations of cells, with only one population of cells responding to vinyl acetate. Acidification in these cells did not plateau but continued to increase at 1000 microM. Bis(p-nitrophenyl)phosphate (BNPP), a carboxylesterase inhibitor, was able to attenuate the vinyl acetate-induced decrease in pHi. Data obtained from the isolated cells were validated using tissue explants. These results are consistent with the proposed mode of action for vinyl acetate and supply further data for developing appropriate risk assessments for vinyl acetate exposure.

Neurokinin-1 receptor (NK-1R), a high-affinity plasma membrane-bound receptor for neurokinin substance P, plays important roles in the onset of the pathophysiological responses. To test whether the transcript levels of gene encoding NK-1R in organs are affected by sidestream cigarette smoke (SSCS) exposure, the C57BL/6 mice were randomly assigned to five groups (six/group) in a study of the dose-effect relationship. The mice were exposed to 0 (filtered room air), 2, 4, 8 and 16 mg total particulate matter (TPM) of SSCS/exposure/day, respectively, for seven days through a nose-only exposure chamber (IN-TOX, Albuquerque, NM, USA). The levels of NK-1R mRNA in the lung, heart, liver, kidney and spleen tissues were detected by reverse transcription-polymerase chain reaction (RT-PCR) techniques and normalized against GAPDH expression. NK-1R mRNA in heart tissue showed SSCS-induced dose-dependent downregulation, with minimum expression at a dose of 8.0 mg TPM. Whereas, the levels of NK-1R mRNA in the liver were upregulated to 2.86 and 5.13-fold after exposure to 2.0 and 4.0 mg TPM of SSCS respectively, then returned to 4.19 and 3.93-fold at the exposure doses of 8.0 and 16.0 mg TPM, respectively, when compared to that of the control. In the kidney, SSCS exposure at a dose of 2.0 TPM, but not higher than that level, induced significant elevation of NK-1R mRNA expression. These findings suggest that there are the paracrine and/or autocrine signalling mechanisms through receptor-ligand interactions. No alteration of NK-1R gene expression was observed in the lungs and spleen tissues in this study. The tissue-specific patterns by which SSCS affect NK-1R gene expression in these organs may partially explain dissimilarity of NK-1R activation and the associated toxicity caused by environmental tobacco smoke.

Nitric oxide and superoxide form the unstable compound, peroxynitrite, which can nitrate proteins and compromise function of proinflammatory cytokines at sites of inflammation. Reduced function of proinflammatory proteins such as IL-8, macrophage inflammatory protein-1alpha, and eotaxin suggest an anti-inflammatory effect of nitration. The effects of nitration on anti-inflammatory cytokines such as IL-10 are unknown. We hypothesized that peroxynitrite would modify the function of anti-inflammatory cytokines like IL-10. To test this hypothesis, the capacity of recombinant human IL-10 to inhibit production of human IL-1beta (IL-1) from LPS-stimulated human PBMC was evaluated. Human IL-10 was nitrated by incubation with peroxynitrite or by incubation with 3-morpholinosydnonimine, a peroxynitrite generator, for 2 h and then incubated with LPS-stimulated PBMC for 6 h, and IL-1 was measured in the culture supernatant fluids. Human IL-1 production was significantly lower in the peroxynitrite- or 3-morpholinosydnonimine-nitrated IL-10 group than in the IL-10 controls (p < 0.05, all comparisons). This finding demonstrates that although peroxynitrite inhibits proinflammatory cytokines, it may augment anti-inflammatory cytokines and further point to an important role for peroxynitrite in the regulation of inflammation.

The acute effects of smoke exposure on inflammatory mediators such as interleukin-10 (IL-10), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha) are not well understood. Our study was designed to measure sputum concentrations of these cytokines in firefighters following low-level smoke exposure. At baseline, participating firefighters underwent blood collection, pulmonary function testing, and sputum induction through inhalation of nebulized hypertonic saline. Study participants later performed overhaul of a structural fire, during which time they wore cartridge respirators and were monitored for smoke exposure. Overhaul involves searching for and extinguishing hidden sources of combustion. One hour following overhaul, blood, pulmonary function data, and induced sputum were again collected. IL-10, IL-8, and TNF-alpha concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in sputum supernatant. In 17 firefighters, baseline sputum IL-10 concentrations were 57.0 +/- 56.8 pg/L, and declined to 16.9 +/- 27.2 pg/L following overhaul (p =.02). No significant changes were observed in sputum IL-8 and TNF-alpha concentrations. Forced vital capacity (FVC) declined significantly in study participants following overhaul. Serum concentrations of Clara-cell protein and surfactant-associated protein A increased significantly following overhaul, indicating increased lung permeability. IL-10 concentrations appear to be exquisitely sensitive to smoke, and studies of IL-10 in sputum should control for recent exposure. Reduced suppression of inflammation by IL-10 may be a mechanism by which low-level smoke exposure causes lung injury.

Overhaul is the stage in which firefighters search for and extinguish possible sources of reignition. It is common practice not to wear respiratory protection during overhaul. Fifty-one firefighters in two groups, 25 without respiratory protection and 26 wearing cartridge respirators, were monitored for exposure to products of combustion and changes in spirometric measurements and lung permeability following overhaul of a structural fire. Testing at baseline and 1 hour after overhaul included forced vital capacity (FVC), forced expiratory volume in one second (FEV1), serum Clara cell protein (CC16), and serum surfactant-associated protein A (SP-A). Overhaul increased CC16 in both groups, indicating increased alveolarcapillary membrane permeability. Contrary to expectations, SP-A increased and FVC and FEV1 decreased in the firefighters wearing cartridge respirators. Changes in FEV1, CC16, and SP-A were associated with concentrations of specific products of combustion or carboxyhemoglobin levels. Firefighter exposures during overhaul have the potential to cause changes in spirometric measurements and lung permeability, and self-contained breathing apparatus should be worn during overhaul to prevent lung injury.

Arsenic is a known human carcinogen. These studies were designed to examine the impact of low arsenite concentrations on immediate early gene expression in precision-cut rat lung slices. Precision-cut lung slices are a versatile in-vitro system for toxicity studies, as they preserve the architecture and cellular heterogeneity of the lung. Since 0.1-100 microM arsenite did not compromise slice viability at 4 hours, effects of arsenite on the expression of c-jun/AP-1, NFkappaB, HSP 32, HSP 72, HSP 60, and HSP 90 were studied, using these concentrations of arsenite at 4 h. Nuclear c-jun was increased by 10 and 100 microM arsenite, while NFkappaB was not affected. Gel-shift assays indicated that 10 microM arsenite resulted in an enhanced DNA-binding activity of both AP-1 and NFkappaB. Confocal microscopic analysis of AP-1 indicated nuclear localization of this transcription factor, mainly in type-II epithelial cells and alveolar macrophages. Nuclear localization of NFkappaB was lower than that observed for AP-1, while most of the NFkappaB was localized to cytoplasm of type-II epithelial cells and alveolar macrophages. HSP 32 was increased by 1.0 and 10 microM arsenite, while HSP 72 was increased by only 100 microM arsenite. HSP 60 and HSP 90 were not changed by arsenite. These studies indicate that noncytotoxic concentrations of arsenite are capable of affecting signal transduction pathways and gene expression in the lung.

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