The effect of extracts from ginger rhizome on inflammatory mediator production

Compounds from rhizomes of Zingiber officinale, commonly called ginger, have been purported to have anti-inflammatory actions. We have used an in vitro test system to test the anti-inflammatory activity of compounds isolated from ginger rhizome. U937 cells were differentiated and exposed to lipopolysaccharide (LPS) from Escherichia coli (1 microg/ml) in the presence or absence of organic extracts or standard compounds found in ginger (6-, 8-, 10-gingerol or 6-shogaol) for 24 h. Supernatants were collected and analyzed for the production of prostaglandin E(2) (PGE(2)) and tumor necrosis factor alpha (TNF-alpha) by standard ELISA assays. Predominant compounds in the organic extracts were identified as 6-, 8- 10-gingerols and 6-, 8-, 10-shogaols. Organic extracts or standards containing gingerols were not cytotoxic, while extracts or standards containing predominantly shogaols were cytotoxic at concentrations above 20 microg/ml. Crude organic extracts of ginger were capable of inhibiting LPS induced PGE(2) (IC(50)<0.1 microg/ml) production. However, extracts were not nearly as effective at inhibiting TNF-alpha (IC(50)>30 microg/ml). Thirty three fractions and subfractions, prepared by column chromatography, were analyzed for bioactivity. Extracts containing either predominantly gingerols or shogaols (identified by HPLC) were both highly active at inhibiting LPS-induced PGE(2) production (IC(50)<0.1 microg/ml), while extracts that contained unknown compounds were less effective (IC(50)<3.2 microg/ml). Extracts or standards containing predominantly gingerols were capable of inhibiting LPS-induced COX-2 expression while shogaol containing extracts had no effect on COX-2 expression. These data demonstrate that compounds found in ginger are capable of inhibiting PGE(2) production and that the compounds may act at several sites.

The effect of turmeric extracts on inflammatory mediator production

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.

Sodium arsenite enhances AP-1 and NFkappaB DNA binding and induces stress protein expression in precision-cut rat lung slices

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.

Adverse respiratory effects following overhaul in firefighters

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.

Rapid reduction of intracellular glutathione in human bronchial epithelial cells exposed to occupational levels of toluene diisocyanate

Toluene diisocyanate (TDI) is a recognized chemical asthmogen, yet the mechanism of this toxicity and the molecular reactions involved have not been elucidated. We have previously shown that TDI vapor forms adducts with the apical surface of the respiratory epithelium, and that it colocalizes with ciliary tubulin. In vitro, we have shown rapid reaction of TDI with glutathione (GSH) and transfer of the bisGS-TDI adduct to a sulfhydryl-containing major histocompatibility complex peptide. This study sought to determine if intracellular GSH is altered following exposure to TDI. We used the dye CellTracker Green (chloromethylfluorescein, CMFDA) for detection of glutathione. One-day and 6-day air-liquid cultures of human bronchoepithelial cells (HBE) were exposed to 20-100 ppb TDI vapor for 5, 15, or 30 min. Cells were subsequently imaged using a confocal microscope. Both 1- and 6-day cultures showed a decrease in intensity of the thiol staining as a function of the TDI exposure dose. Doses as low as 20 ppb, the current permissible exposure limit (PEL) to TDI, resulted in rapid (within 5 min) decreases in fluorescence. The decreased fluorescence was not due to cytotoxicity or decrease in either esterase or glutathione-S-transferase activity, enzymes necessary for activation of the fluorescence of CMFDA. The decrease in glutathione levels was verified using another fluorescent label, ThioGlo(TM) 1, and cell extracts. In addition, the mucus produced by 6-day air-liquid interface HBE cells in response to TDI exposure appeared to be protective, as HBE cells underlying mucus retained more fluorescence than did cells in the same cultures that were not covered with mucus. These results, along with previous data, strongly suggest that TDI enters pulmonary cells and reacts rapidly with intracellular GSH, and that this can occur at the current PEL of 20 ppb. This rapid reaction suggests the importance of cellular thiols in TDI-induced pulmonary disease.

Short-term pulmonary response to inhaled JP-8 jet fuel aerosol in mice

B6.A.D. (Ahr(d)/Nat(s)) mice were utilized to investigate the short-term pulmonary response to JP-8 jet fuel (JP-8) aerosol inhalation. Mice were nose-only exposed to atmospheres of 0 to 118 mg/m3 for 1 h/d over a period of 7 days to further test the hypothesis that JP-8 concentrations below the permissible exposure level (PEL) of 350 mg/m3 will induce lung injury. At 24 to 30 hours after the final exposure, pulmonary function and respiratory permeability were measured on anesthetized mice and then randomly assigned for bronchoalveolar lavage or histopathology. Bronchoalveolar lavage fluid (BALF) was analyzed for total protein, lactic dehydrogenase (LDH), N-acetyl-beta-D-glucosaminidase (NAG), and cytology. Respiratory permeability increases were observed following doses of 48 and 118 mg/m3 and were supported by concomitant BALF increases in total protein and LDH. Conversely, NAG and alveolar macrophage levels decreased following the same exposure concentrations. Morphological lung injury was characterized by the targeting of bronchiolar epithelium and consisted of perivascular edema, Clara cell vacuolization, and necrosis. Alveolar injury included sporadic pulmonary edema, intra-alveolar hemorrhage, and alterations in type II epithelial cells. These results indicate that repeated inhalation of aerosolized JP-8 induces physiological, biochemical, cellular, and morphological lung injury. This study also provides evidence for the reevaluation of the 350 mg/m3 PEL for more volatile petroleum distillates with regard to respirable aerosols.

Nedocromil sodium inhibits canine adenovirus bronchiolitis in beagle puppies

Nedocromil sodium is a nonsteroidal anti-inflammatory drug used to control asthmatic attacks. Our hypothesis is that nedocromil sodium inhibits virus-induced airway inflammation, a common trigger of asthma. We nebulized nedocromil sodium into beagle dogs (n = 10, mean +/- SEM ages: 149 +/- 13 days) before and after inoculation with canine adenovirus type 2 (CAV2). Control dogs (n = 10) received saline aerosols and were either infected with CAV2 (Sal/CAV2, n = 7, mean +/- SEM ages: 140 +/- 11 days) or were not infected (Sal/Sal, n = 3, ages: 143 +/- 0 days). All dogs were anesthetized with choralose (80 mg/kg i.v.), intubated, and mechanically ventilated. Pulmonary function tests and bronchoalveolar lavage (BAL) were performed using standard techniques. Pulmonary function tests revealed no significant change between the nedocromil sodium and non-nedocromil-treated groups. The percentage of infected bronchioles was quantitated as the number of inflamed airways of 40 bronchioles examined times 100 for each dog. Nedocromil-treated dogs had significantly (p < 0.05) less mucosal inflammation (mean +/- SEM, 39% +/- 5%), epithelial denudation (36% +/- 5%), and BAL neutrophilia (11 +/- 3) than did Sal/CAV2 dogs (51% +/- 6%, 57% +/- 4%, and 33% +/- 8%, respectively). We concluded that pretreatment with nedocromil sodium aerosols attenuated CAV2-induced airway inflammation in these beagle puppies.

Functional alterations of alveolar macrophages subjected to smoke exposure and antioxidant lazaroids

Acute inhalation of diesel fuel-polycarbonate plastic (DFPP) smoke causes severe lung injury, leading to acute respiratory distress syndrome (ARDS) and death. It has been reported that the initiation of acute lung injury is associated with the activation of pulmonary alveolar macrophages (PAM). To further explore the pathogenesis, alveolar macrophages (AM) of New Zealand rabbits ventilated and exposed to a 60 tidal volume of DFPP smoke in vivo were recovered at 1 h post-smoke. Smoke exposure induced significant increases in both mRNA and protein levels for PAM tumor necrosis factor-alpha (TNF-alpha), when compared to smoke control. Smoke also induced a biphasic response (inhibited at 2 h, enhanced at 24 h after cell isolation) in the production of superoxide (O2-) by PAM. However, aerosolized lazaroid, U75412E (1.6 mg/kg body weight), significantly attenuated smoke-induced expression in AM TNF-alpha at the protein level but not at the mRNA level, and smoke-induced changes in AM production of O2-. This study suggests that highly expressing AM TNF-alpha following smoke may be a key contributor to the cascade that establishes an acute injury process and exacerbates oxidant-derived cell injury. Whereas, the lazaroid may ameliorate smoke-induced lung injury by attenuating AM TNF-alpha release, in addition to its primary antioxidative mechanism.

Toluene diisocyanate colocalizes with tubulin on cilia of differentiated human airway epithelial cells

Toluene diisocyanate (TDI), a highly reactive industrial chemical with widespread use in the manufacture of polyurethane and plastics, is the leading cause of occupational asthma associated with chemical exposure. We report the effects of TDI vapor (20, 100, 500, 1000 ppb) in vitro on differentiated human bronchial epithelial cells. Increased mucus was observed by electron microscopy at all TDI concentrations. Cytotoxicity, as evidenced by cell pyknosis and DNA fragmentation, was detected following a 30-min exposure to TDI concentrations of 100 ppb or higher. At 1000 ppb, transepithelial resistance was lost. Using confocal microscopy and double staining, TDI was found colocalized with ciliary tubulin in cultures that had been exposed to 20 and 100 ppb. These findings are the first to identify TDI binding to human pulmonary epithelial cells and indicate extensive binding to the cilia of differentiated epithelial cells. The in vivo implications of these findings include decreased ciliary movement and longer retention of TDI and hence increased exposure. Altered cytoskeletal-derived signal transduction may be a consequence of tubulin involvement. The effects of such changes on respiratory sensitization remain to be explored.

Early alterations of lung injury following acute smoke exposure and 21-aminosteroid treatment

In a simulated fire-related smoke exposure protocol, New Zealand white rabbits were utilized to investigate the potential effects of the 21-aminosteroid (lazaroid) analog U75412E on the early events of acute lung injury. Inhalation of a total of 1.6 mg/kg U75412E aerosolized at a rate of 1.53 mg/min at 0.5 hr after smoke exposure significantly attenuated the extent of lung injury at 1 hr, as evidenced by decreased bronchoalveolar lavage (BAL) concentration of total protein, 6-keto-prostaglandin F1-alpha, and blood gas defect. Histopathologic examination demonstrated that the lazaroid significantly attenuated smoke-induced lung injury as evidenced by a decrease in wet lung/body weight ratio, necrosis, and sloughing of airway epithelial cells. Electron microscopy showed that the lazaroid decreased smoke-induced interstitial edema and the vacuolization of alveolar type II epithelium (21.6 +/- 9.7 vs 8.5 +/- 3.6 vacuoled blebs/cell, smoke only vs smoke + lazaroid). However, U75412E did not attenuate smoke-induced changes in BAL concentration of tumor necrosis factor-alpha, total cell count, and granulocyte percentage. These observations suggest that U75412E may exert its action through cooperative mechanisms, such as the modulation of arachidonic acid metabolism, in addition to its characterized antioxidative effects.

1,2-Dichlorobenzene-induced lipid peroxidation in male Fischer 344 rats is Kupffer cell dependent

1,2-Dichlorobenzene (1,2-DCB) is a potent hepatotoxicant in male Fischer 344 (F344) rats and previous studies have suggested that reactive oxygen species may play a role in the development of hepatotoxicity. Since reactive oxygen species can damage lipid membranes, this study was conducted to determine the extent of lipid peroxidation after administration of 1,2-DCB by immuno-histochemical analysis of 4-hydroxynonenal (4-HNE) protein adduct formation in liver and conjugated diene formation in liver and serum. The contribution of Kupffer cells to the lipid peroxidation was also investigated. Male F344 rats were administered 1,2-DCB (3.6 mmol/kg i.p. in corn oil) and killed at selected times between 3 and 48 h. Time course studies revealed the greatest abundance of 4-HNE protein adducts in the centrilobular regions of the liver 24 h after 1,2-DCB administration, with much lower levels at 16 h. Adducts were present in necrotic and vacuolized centrilobular hepatocytes of 1,2-DCB treated rats but not in livers of controls. Further, conjugated dienes were significantly increased in liver and serum 16 and 24 h after 1,2-DCB administration, peaking at 24 h. These data correlated with hepatocellular injury, determined by serum alanine aminotransferase activity and histopathological evaluation, which was markedly elevated within 16 h and peaked at 24 h. When rats were pretreated with gadolinium chloride (GdCl3; 10 mg/kg i.v. 24 h prior to 1,2-DCB), an inhibitor of Kupffer cells, hepatotoxicity was decreased by 89 and 86%, at 16 and 24 h, respectively. Conjugated diene concentrations were decreased to control values at these times after 1,2-DCB administration. Moreover, no 4-HNE protein adducts were detected in livers of 1,2-DCB-treated rats pretreated with GdCl3. Finally, Kupffer cells isolated from 1,2-DCB-treated rats produced significantly more superoxide anion than Kupffer cells isolated from vehicle controls. These data, along with previous findings, suggest that lipid peroxidation associated with 1,2-DCB is mediated in part by Kupffer cell-derived reactive oxygen species.

Human alveolar fractal dimension in normal and chronic obstructive pulmonary disease subjects

We have determined that fractal analysis of the alveolar perimeter (Df) changes with aging in human lung tissue in twenty-nine patients, age range of 25 hours to 76 years, who died of non-respiratory related causes. There was a very significant difference (p = 0.0004) in Df between the young (less than 16 years old, N = 9, mean Df of 1.047 [0.01]) and adult (greater than 16 years old, N = 20, mean Df of 1.093 [0.013]) groups. Furthermore, there was a significant difference in Df between the Adult group and the group of patients who died of chronic obstructive pulmonary disease (COPD, N = 10) (p = 0.012). Additionally, the Df values for the COPD and cystic fibrosis (CF, N = 5) groups were virtually identical; 1.061 and 1.070, respectively. Regression analysis showed a significant (p = 0.0041) exponential relationship with a correlation coefficient of 0.59 between aging and Df. We have demonstrated that the correlation between Df and aging in humans is an exponential function and that the end-stage pulmonary diseases of COPD and CF decrease Df.

A free radical scavenger (Lazaroid U75412E) attenuates tumor necrosis factor-alpha generation in a rabbit model of smoke-induced lung injury

The lazaroid (21-aminosteroid) analogue U75412E was evaluated in rabbits exposed to diesel fuel-polycarbonate plastic smoke. Inhalation of total of 4.6 mg U75412E aerosolized at a rate of 1.53 mg/min for 3 min before or after smoke significantly prevented or limited the extent of alveolar hypoventilation, interstitial edema, and tumor necrosis factor-alpha (TNF-alpha) by pulmonary alveolar macrophages (PAM) ex vivo observed at 2 h. The smoke-induced changes in wet lung/body weight ratios and the production of superoxide (O2-) by PAM ex vivo were also attenuated by the drug treatment after smoke exposure (p < 0.05). This study suggests that lazaroids may ameliorate the oxygen-radical-initiated cytokine processes and inflammation cascade as a result of the smoke insult.

Modulation of Kupffer cell and peripheral blood monocyte activity by in vivo treatment of rats with all-trans-retinol

Previous studies have shown that large doses of vitamin A potentiate chemical-induced liver injury and that the Kupffer cell is directly involved in this potentiation. Therefore, these studies were designed to determine if Kupffer cells isolated from vitamin A treated male Sprague-Dawley rats (75 mg/kg/day for 3-7 days as all- trans-retinol) had altered activity and function. Respiratory activity of Kupffer cells isolated from rats treated with vitamin A for 3 to 7 days markedly increased. Similarly, phagocytic activity was significantly elevated (up to 9-fold) after exposure to vitamin A for 3 to 7 days. Production of reactive oxygen species, measured by luminol-enhanced chemiluminescence of Kupffer cells isolated after 7 days of vitamin A exposure, was significantly higher than that of control cells when stimulated with opsonized zymosan. Also, the release of superoxide anion by individual Kupffer cells isolated from vitamin A treated rats was nearly three times greater than that of control cells. Basal production of tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2) production were significantly elevated in Kupffer cells isolated from rats treated with vitamin A. Lastly, peripheral blood monocytes (PBMC) isolated from rats treated with vitamin A for 7 days had a significantly greater respiratory activity, as well as TNF-alpha and PGE2 production, than PBMC isolated from control rats. Our data suggest that large doses of vitamin A enhance both Kupffer cell and PBMC function. Upregulation of the activity by these phagocytic cells may play a role in the vitamin A potentiation of chemical-induced liver injury.

Fractal analysis of lung alveoli during the acute phase vs. repair phase of an adenoviral infection in canines

Acute viral respiratory infections are commonly associated with alterations in lung growth. Recently, fractal techniques have been demonstrated to show changes in alveolar perimeter after canine adenovirus type 2 (CAV2) infection in a beagle puppy model. In the present study, we investigated whether the fractal dimension (Df) of the alveolar perimeter was changed in the acute phase (2-3 weeks after inoculation, 131d CAV2 group) or during the recovery phase (approximately 22 weeks after inoculation, 235d CAV2 group) after a single bout of CAV2. There were sham CAV2 groups, 130d and 238d controls, corresponding to the CAV2 groups. The Df of alveolar perimeter length was significantly increased in the 235d CAV2 puppies compared to all of the other beagle puppy groups. On the other hand, the fractal dimensions for alveolar perimeter length for the other beagle puppy groups were very similar. In a related human study of patients (age range of 25 h to 19 y, N = 11), who died of non-respiratory causes, showed no consistent change in Df of alveolar perimeter length with normal lung growth and development. We conclude that fractal analysis of alveolar perimeter length can be used as an index of permanent lung injury after insult to the growing lungs.

The prophylactic effects of U75412E pretreatment in a smoke-induced lung injury rabbit model

The effects of the lazaroid analogue U75412E (21-[4-(3-ethylamino-2-pyridinyl)-1-piperazinyl]-16 alpha-methylpregna-1,4,9]-(11)-triene-3,20-dione) were examined in an acute lung injury rabbit model. Standard doses of 0, 8 and 16 mM U75412E were aerosolized and ventilated into the lungs for 3 min. via an endotracheal tube. A 60 tidal volume dose of diesel fuel-polycarbonate plastic smoke was then instilled, followed by mechanical ventilation for one hour. Pretreatment with 16 mM U75412E significantly increased blood PaO2 and pH values, and decreased blood PaCO2 as compared to smoke only exposures. It also significantly decreased the total cell counts and granulocytes in bronchoalveolar lavage fluid, and the ability of pulmonary alveolar macrophages to produce tumour necrosis factor-alpha in vitro after cell isolation and culture. Histopathology indicated that 16 mM U75412E pretreatment attenuated increases in wet lung/body weight ratios, inflammatory focus, and interstitial oedema associated with smoke insult. In summary, U75412E pretreatment may possess the potential to improve acute smoke-induced lung injury, in part, through modulation of tumour necrosis factor-alpha production from pulmonary alveolar macrophages.

Neutral endopeptidase (NEP) and its role in pathological pulmonary change with inhalation exposure to JP-8 jet fuel

Through a simulated flightline exposure protocol, Fischer 344 rats (F344) were subjected to an aerosol/vapor mix of the military jet fuel, JP-8. Previous studies with this model of lung injury have revealed significant increases in pulmonary resistance, increased alveolar clearance of 99mTcDTPA, and a decrease in bronchoalveolar lavage fluid (BALF) concentration of the neuropeptide substance P (SP). Exposures to JP-8 were nose-only and for one hour daily. Six groups of Fischer 344 rats were exposed for 7, 28, or 56 days at two JP-8 concentrations (low dose = 469-520 mg/m3/hr, high dose = 814-1263 mg/m3/hr). Exposed groups were matched with longitudinal controls. In response to JP-8 inhalation, exposure animals demonstrated a dose-dependent as well as duration-determined reduction in BALF SP concentration. Both JP-8 concentrations caused significant pathological changes in lower pulmonary structures.

Inhalation exposure to JP-8 jet fuel alters pulmonary function and substance P levels in Fischer 344 rats

In a simulated military flightline exposure protocol, Fischer 344 rats (F344) were used to investigate the pulmonary effects of JP-8 jet fuel inhalation. Exposures were nose only and for 1 h daily. Groups were exposed for 7 days (7D) or 28 days (28D). Each exposure group had a matched longitudinal control group (LC7 and LC28). Exposure concentrations of 520 mg m-3 caused an increase in dynamic compliance after 7 days of exposure, but compliance changes were not seen with continued exposure (28D, 495 mg m-3). Pulmonary resistance was increased in both 7- and 28-day JP-8-exposed groups. Changes in pulmonary function were accompanied by a decrease in substance P concentrations from the bronchoalveolar lavage fluid (BALF). No significant change was observed in BALF levels of 6-keto-PGF1 alpha, the stable metabolite of prostacyclin, which is a marker of endothelial cell function. The JP-8-exposed rats gained significantly less weight during the study period than the LC7 and LC28 groups, and the lungs of the 7D group were heavier by wet lung/body weight ratio (WtL/WtB). Alveolar clearance of technetium-labelled diethylenetriamine pentaacetate ([99mTc]DTPA) was increased in jet fuel-exposed groups. Light microscopy showed no pathological evidence of lung injury. Recovery from the early pulmonary effects of JP-8 inhalation occurred with continued exposure, as seen by recovery of pulmonary compliance and WtL/WtB.

Locomotive forces produced by single leukocytes in vivo and in vitro

We report here the first time-resolved measurements of the forces produced during the migration of single leukocytes in vivo and in vitro. Pulmonary macrophages from hamsters and mice, in vitro, and Nembutal (pentobarbital sodium)-anesthetized hamster neutrophils, in vivo, generated maximum locomotive forces ranging from 1.9 to 10.7 nN or tenths of microdynes. Force production was periodic and correlated with the length of the leading lamellipod but not with generalized cell ruffling. Although the extension of the leading lamella is critical to locomotive force generation, these direct measurements suggest that lamellar extension may not arise from the same contractile processes driving forward motion of the cell mass. Indeed, cell ruffling, lamellar extension, and locomotive force generation may be differentially controlled and have different origins. This technique may be extended to test numerous hypotheses of how these and other nonmuscle cells crawl.

Changes in lung permeability correlate with lung histology in a chronic exposure model

In a simulated military flight-line exposure protocol, the effects of JP-8 jet fuel exposure on lung epithelial permeability were evaluated in male Fischer 344 rats (F344). Exposures were nose-only and for one hour daily. Groups were exposed for 7, 28, and 56 days. A protocol for administering a low dose (500mg/m3/hr) and a high dose (813-1094mg/m3/hr) of JP-8 jet fuel was used. Longitudinal sham-exposure groups (no jet fuel) for 7, 28, and 56 days were included in the protocol. Lung epithelial permeability was measured by clearance of technetium-labeled diethylenetriamine pentaacetate (99mTcDTPA, molecular weight = 492 daltons, physical half-life = 6.02 hours). The percent clearance of 99mTcDTPA per minute was calculated. Alveolar epithelial clearance for JP-8-exposed rats was dependent on both exposure concentration and duration. It was noted that at low-dose exposure concentrations alveolar epithelial clearance of 99mTcDTPA returned to low levels (LD56 = 1.09% per min; LC56 = 0.98% per min), suggesting recovery as evidenced by microscopic exam. The corresponding 56-day high-dose group (n = 10) had a significantly higher (p < 0.05) value of 2.25% per minute. The 28-day low-dose (n = 15) and high-dose (n = 20) groups had clearance values that were significantly increased from their longitudinal control group (n = 17). The alveolar epithelial permeability values were 2.51, 1.95, and 1.20, respectively. The seven-day longitudinal control, low-dose, and high-dose groups had alveolar permeability values of 1.57, 2.16, and 2.07, respectively. The lung histology correlated with the clearance values. Electron micrographs showed that all groups had interstitial edema resulting from endothelial damage. There was apparent thickening of the alveolar septa, and alveolar macrophages were activated in all groups. Lung permeability data, as determined by 99mTcDTPA alveolar clearance, indicated that lung injuries peaked at 28 days of jet fuel exposure, and this finding corresponded with the histology data. There was a discrepancy in the seven-day group between the number of cells and the 99mTcDTPA clearance values. The HD7 group had a total cell count significantly higher than all other groups, but the 99mTcDTPA clearance values in that group were not significantly different from that of any other group.

Effect of arsenic exposure on alveolar macrophage function. II. Effect of slightly soluble forms of As(III) and As(V)

The pulmonary toxicity of a substance depends on a number of chemical and physical characteristics, including the solubility of the compounds. In the lung, insoluble forms of metals may be more tumorigenic than soluble forms despite the fact that this effect has not been quantitated and the mechanism of action has not been elucidated. The toxic effects of slightly soluble forms of As(III) and As(V) were evaluated by determining alteration in function of pulmonary alveolar macrophages (PAM) following in vivo and in vitro exposure. Male Sprague-Dawley rats were used throughout. Twenty-four hours following intratracheal instillation of 1 mg/kg (as arsenic) of either arsenic trisulfide (As(III)) or calcium arsenate (As(V)), PAM were lavaged and analyzed for alterations in superoxide (O2-), and tumor necrosis factor (TNF-alpha) production. There were no differences in bronchoalveolar lavage fluid TNF-alpha. PAM lavaged from As(V)-exposed animals showed significant increases in O2- production and in basal release of TNF-alpha. PAM lavaged from animals receiving As(III) did not show significant alterations. To test the direct effects of arsenic, PAM were lavaged from control animals and exposed to concentrations of 0.1 to 300 micrograms/ml arsenic in vitro for up to 24 hr. Doses used were not cytotoxic to PAM, since LDH release was not significantly increased. Significant dose-dependent inhibition of O2- production was only evident after 24 hr exposure to arsenicals. Both As(III) and As(V) produced inhibition at concentrations of 10 micrograms/ml. Suppression of LPS-induced release of TNF-alpha also occurred at similar concentrations for both arsenicals (4-5 micrograms/ml). Neither arsenical inhibited prostaglandin E2 production. Measurement of soluble arsenic concentrations indicated dissolution of the compounds could not account for all of the effects seen. Arsenic-induced alteration in PAM function may compromise host defense.

Effect of arsenic exposure on alveolar macrophage function. I. Effect of soluble as(III) and as(V)

Despite potential differences in the mechanism and potency of toxicity between the two common oxidation states of arsenic (As(III) and As(V)), assessments of the risk from inhaled arsenic generally ignore the oxidation state of inorganic arsenicals. Differences between potency and toxicity of As(III) and As(V) were evaluated by determining alteration in function of pulmonary alveolar macrophages (PAM) following in vivo and in vitro exposure to soluble arsenic. Male Sprague-Dawley rats were used throughout. One day following intratracheal instillation of 1 mg/ml (as arsenic) of either sodium arsenite (As(III)) or sodium arsenate (As(V)), PAM were lavaged and analyzed for alterations in superoxide (O2-), prostaglandin E2 (PGE2), and tumor necrosis factor (TNF-alpha) production. There were no differences in bronchoalveolar lavage fluid PGE2 or TNF-alpha. PAM lavaged from As(V)-exposed animals showed significant increases in O2- production. In vivo exposure to either oxidative form of arsenic decreased basal and lipopolysaccharide (LPS)-induced release of TNF-alpha production by PAM, but did not suppress LPS-induced production of PGE2. To test the direct effects of arsenic on PAM function, PAM were lavaged from control animals and exposed, in vitro, to either arsenical for up to 24 hr to concentrations of 0.1 to 300 micrograms/ml arsenic. Doses used were not cytotoxic to PAM, since LDH release was not significantly increased, even at the highest dose. Significant dose-dependent inhibition of O2- production was only evident after 24 hr exposure to arsenicals. As(III) was more potent than As(V), inhibiting O2- at concentrations as low as 0.1 micrograms/ml compared to 1.0 micrograms/ml of As(V). Suppression of LPS-induced release of TNF-alpha also occurred at lower concentrations of As(III), 50% inhibition at 0.15 micrograms/ml, compared to As(V), 50% inhibition at 1.8 micrograms/ml. While As(III) exposure had no affect on PGE2 production, As(V) caused inhibition of LPS-induced PGE2 production at concentrations above 1.0 micrograms/ml. Differences between As(III) and As(V) indicate that different mechanisms and/or potencies exist between the two arsenic species. Arsenic-induced alteration in PAM function may compromise host defense against infections and alter immune surveillance.

Vitamin A pretreatment and bleomycin induced rat lung injury

Possible antioxidant effects of pretreatment with vitamin A on bleomycin-induced rat lung injury were studied. Intratracheal bleomycin was administered to rats pretreated with vitamin A (50,000 IU/day) or vehicle control. Analysis of bronchoalveolar lavage fluid (BAL) total and differential cell counts, lung weight, lung pathology, and alveolar macrophage superoxide anion production were performed before and at various time points after the instillation of bleomycin. Bleomycin with vehicle raised total BAL cell count and the per cent of BAL neutrophils at day 7 post injury. The percent of lung involved with pneumonitis, the lung wet weight/body weight ratio and the alveolar macrophage superoxide anion production were also increased after bleomycin alone compared to the group pretreated with vitamin A. Rats pretreated with vitamin A demonstrated a statistically significant reduction in total BAL cell count and in alveolar macrophage superoxide anion production 7 days after bleomycin compared with vehicle control. Lung wet weight/body weight ratio 7 days after bleomycin was reduced in the vitamin A treated rats. There was a trend to less pneumonitis in the vitamin A pretreated group. These data suggest that vitamin A attenuates bleomycin induced pulmonary damage by a mechanism which involves inhibition of bleomycin-induced alveolar macrophage superoxide anion production.

Fractal and morphometric analysis of lung structures after canine adenovirus-induced bronchiolitis in beagle puppies

Acute viral respiratory infections are commonly associated with alteration in lung growth and with chronic obstructive disease. However, it is difficult to quantify these changes in lung function. We determined that the recently described techniques of fractal analysis gave additional information about the changes in lung function after viral illness compared to standard morphometric techniques. Fractal and morphometric parameters change with lung growth after acute infection with canine adenovirus type 2 (CAV2, n = 5) or no infection (controls, n = 6) in beagle puppies. Lung pathological studies showed areas of obliterative bronchiolitis and chronic small airways inflammation but no emphysema in the CAV2-infected puppies. Morphometric studies at approximately 236 days of age demonstrated accelerated lung growth in the CAV2-infected dogs as evidenced by significant increases in lung volume (VL) and internal surface area (ISA). Fractal analysis showed an increased fractal dimension (Df) of the alveolar perimeter length in the CAV2 group associated with increased growth that was similar to the percentage change in VL and ISA. These data suggest that a single infection with CAV2 in beagle puppies accelerates lung growth and increases the complexity (Df) of the alveolar structure.

Aerosolized lipopolysaccharide increases pulmonary clearance of 99mTc-DTPA in rabbits

Bacterial endotoxins alter the permeability of endothelium, but little is known of their effect on epithelium. We exposed specific pathogen-free rabbits to aerosolized Pseudomonas aeruginosa LPS or saline and performed serial measurements of RL, Cdyn, BP, WBC count and differential, and platelet counts. Pulmonary 99mTc-DTPA half-life was measured 4, 6, or 8 h after exposure. The animals were sacrificed and BAL performed. Background and PMA-stimulated superoxide production was measured from individual AM using electrooptical determination of reduction of NBT. Lung tissue was processed for light microscopy and ratio of wet to dry weight. 99mTc-DTPA half-life was significantly shorter in LPS-exposed animals at 6 h (p < 0.05) and 8 h (p < 0.001). There were no differences in Cdyn, RL, BP, WBC, differential, platelet, or BAL cell count at any time between groups. No histologic changes or differences in lung wet to dry weight ratios were found. PMA-stimulated AM superoxide production was significantly increased (p < 0.01) in LPS-exposed animals. This effect was time dependent and could be duplicated in AM from control animals following a 4-h incubation with LPS, lavage fluid from LPS-exposed animals, or recombinant murine TNF. These results demonstrate that aerosolized Pseudomonas LPS increases pulmonary epithelial permeability and primes AM superoxide production.

Effect of smoke inhalation on immediate changes in lung chemical mediators

We studied the effects of acute smoke exposure on lung and alveolar macrophage (AM) function in New Zealand white rabbits. Six rabbits were exposed to smoke (SE, N = 6) and a control group of rabbits (SS, N = 6) were exposed to sham smoke. The smoke exposure consisted of 60 tidal volume breaths of air and smoke which were aspirated by syringe from a sampling port of a smoke chamber. The smoke was generated by the combustion of 20 ml diesel fuel and 0.2 g polycarbonate plastic shavings. The smoke was administered in 8-9 min. The rabbits were then killed and the lungs were removed for lavage. Acute smoke exposure caused a significant (p = 0.037) increase in bronchoalveolar lavage fluid levels of leukotriene B4 in the SE rabbits; 643 (+/- 30, SEM) pg/ml compared to 539 (+/- 43, SEM) pg/ml for SS rabbits at 3-4 min post-exposure. Lung surfactant, measured as mumoles/kg phosphatidylcholine, was decreased (p = 0.039) in SE rabbits' bronchoalveolar lavage fluid, 1.07 (+/- 0.12, SEM) -vs- 1.45 (+/- 0.15, SEM) for SS. Furthermore, cultured SE alveolar macrophage superoxide secretion after stimulation with phorbol myristate acetate was significantly decreased versus SS alveolar macrophage superoxide values at 40 min in culture. We conclude that acute smoke exposure causes immediate increases in bronchoalveolar lavage fluid levels of LTB4, and decreases in alveolar macrophage superoxide production and lung surfactant. These changes in chemical mediators may contribute to the lung injury caused by the smoke insult.

The role of platelet-activating factor in the pulmonary response to inhaled bacterial endotoxin

Quantitative morphometric analyses were carried out on animals subjected to aerosols of bacterial endotoxin (LPS) to further define the role of platelet-activating factor (PAF) in the development of pulmonary injury. Hamsters were exposed to either saline aerosol or dilute aerosols of LPS (4 micrograms/m3) for standard lengths of time. Within each aerosol exposure group, animals were further subdivided into groups receiving either the PAF receptor binding antagonist, RP 48740, or saline injections. LPS inhalation resulted in decreased fixed lung volume, increased sequestration of polymorphonuclear leukocytes and platelets in pulmonary capillaries, increased type I epithelial and endothelial cellular volumes, increased cellular interstitium, and increased endothelial pinocytotic vesicles. Treatment with RP 48740 either attenuated or abolished the ability of inhaled LPS to induce these structural alterations. The PAF antagonist also inhibited LPS-induced increases in pulmonary capillary permeability. It is concluded that PAF is one of the major injury-promoting mediators released upon inhalation exposure to environmentally realistic concentrations of bacterial endotoxin. A major but not exclusive target of this mediator is the pulmonary vascular endothelium.

Heterogeneity in superoxide production as measured by nitro blue tetrazolium reduction from individual PAM

Heterogeneity in superoxide (O2-.) production (as determined by the reduction of nitro blue tetrazolium to a diformazan precipitate), cell volume, and cell spreading were measured from single rat pulmonary alveolar macrophages (PAM). Of the 330 cells that produced O2-. due to stimulation by adherence, the maximum diformazan produced (MAX) varied between 1.8 and 47.2 fmol and the maximum (initial) rate of diformazan production (R) varied between 2.2 and 81.7 X 10(-3) fmol/s. Only six PAM of 336 analyzed failed to produce O2-. suggesting that O2-. production is not a specific function of a small subpopulation of PAM but rather that all PAM are capable of producing O2-.. Importantly, O2-. production by single cells showed extensive heterogeneity that did not correlate (r2 less than 0.12) with individual cell volumes, suggesting that the observed heterogeneity may not be due to differences in maturation and/or differentiation. However, when the single cell data were grouped into cell volume subfractions small but increasing linear trends (r2 greater than 0.81) in MAX and R were found. This discrepancy suggests that PAM heterogeneity in O2-. fraction cannot be estimated adequately by measurements on subpopulations of cells.

Piriprost pretreatment attenuates the smoke-induced increase in 99mTcDTPA lung clearance

We studied the effects of acute smoke exposure on lung permeability, eicosanoids, and inflammatory cell activity. Thirty-five New Zealand white rabbits were anesthetized, paralyzed, and exposed to 60 tidal volume breaths of diesel fuel-polycarbonate plastic smoke or sham smoke within 10 min. At 1 h postexposure the rabbits were killed and their lungs were removed for bronchoalveolar lavage (BAL) or pathologic procedures. Smoke exposure caused decreases in technetium-labeled diethylenetriamine pentaacetate (99mTcDTPA, mol. wt. 492 Da) biological half-life (t1/2), BAL plasminogen activator, and BAL leukotriene B4 (LTB4). In addition, alveolar macrophage acid phosphatase enzyme activity increased in smoke-exposed rabbits. The leukotriene synthesis inhibitor, piriprost (U-60,257), given before smoke exposure, caused attenuation of the changes in 99mTcDTPA uptake and plasminogen activator, swelling of type I alveolar cell epithelium, a large increase in lung inflammatory cells, and decreases in BAL LTB4, prostaglandin E2 (PGE2), and TxB2 (stable metabolite of thromboxane, TxA2). We conclude that changes in alveolar-capillary barrier permeability and plasminogen activator activity occur within 1 h after exposure to smoke and may play an early role in the inflammatory process associated with smoke inhalation injury. Furthermore, piriprost attenuates the smoke-induced increase in alveolar-capillary barrier permeability and decrease in plasminogen activator activity and causes a swelling of type I alveolar epithelium. However, our data suggest that neither lung eicosanoids or the alveolar macrophage lysis process plays a major role in the smoke-induced increase in alveolar-capillary barrier permeability.

Functional units in rainbow trout (Salmo gairdneri, Richardson) liver: III. Morphometric analysis of parenchyma, stroma, and component cell types

Hepatic stroma and parenchyma with its component cell types were quantitatively described in adult male and female actively-spawning 5-year-old rainbow trout (Salmo gairdneri, Richardson). Point-count morphometry of glycol methacrylate sections estimated volume compartments for stroma and parenchyma. Veins composed 85% of the stroma while arteries and bile ducts occupied approximately 6-7% each. Parenchyma accounted for 95% of hepatic volume. Point-count morphometry of transmission electron micrographs estimated volume compartments as well as numerical and surface density measurements for parenchymal components. Within the hepatic parenchymal compartment, hepatocytes occupied 85% and showed significant sex differences. Female hepatocytes were significantly more numerous but were smaller, only 60% of the volume of male hepatocytes. Since hepatocyte nuclear volume was equal in both sexes, differences were due to reduced cytoplasmic volume in females. Perisinusoidal macrophages of females occupied larger volumes of their respective parenchymal compartments, and their larger mean cytoplasmic volumes suggested activation. Biliary epithelial cells of preductules and ductules were numerous. Ratios of numerical density of hepatocytes to biliary epithelial cells were consistent with a tubular arrangement of hepatocytes. Factors possibly mediating the sexual dimorphism are discussed.

A kinetic model of superoxide production from single pulmonary alveolar macrophages

A kinetic model was developed to describe the production of superoxide (O2-) by single pulmonary alveolar macrophages (PAM). Model predictions were compared with experimental results obtained from single rat PAM. The O2- was quantified by measuring the reduction of nitro blue tetrazolium (NBT) to a diformazan precipitate (NBTH2) from video-recorded images of individual cells. The kinetic model considered three reactions: 1) the production of extracellular O2- from the reduction of oxygen by NADPH oxidase using intracellular NADPH as the substrate, 2) the subsequent dismutation of O2- to form H2O2, and 3) the reaction of O2- and NBT to form diformazan. NBT specificity for O2- was analyzed by comparing results in the presence and absence of superoxide dismutase (SOD) that catalyzes the dismutation of O2- to H2O2. Measured PAM heterogeneity was accounted for by varying the concentration of intracellular NADPH, its rate of depletion, and the concentration of intracellular NADPH oxidase in the kinetic model. Model predictions compared favorably with experimental results except when SOD was present. This discrepancy may be due to diffusional limitations because NBT is a relatively small molecule (818 mol wt) compared with SOD (34,000 mol wt). In addition, the cell surface is both ruffled and negatively charged, which may introduce steric hindrances and/or electrostatic effects, since SOD is also negatively charged, whereas NBT is positively charged.

Functional units in rainbow trout (Salmo gairdneri, Richardson) liver: II. The biliary system

The intrahepatic biliary system was studied in the rainbow trout (Salmo gairdneri), a teleost known to form liver neoplasms after exposure to various carcinogens. Normal adults (N = 25) were examined using light microscopic, enzyme histochemical, and transmission and scanning electron microscopic methods. In light micrographs, longitudinal arrays of hepatocytes appeared as double rows incompletely divided by elongated darkly stained cells. Electron micrographs showed tubules of five to nine pyramidally shaped hepatocytes with their apices directed toward a central biliary passageway and their bases directed toward sinusoids. Sequentially, beginning with hepatocytes, biliary passageways included canaliculi, preductules, ductules, and ducts. Canaliculi were short and joined transitional passageways (preductules) formed by junctional complexes between plasma membranes of hepatocytes and small, electron-dense cells with a high nuclear to cytoplasmic ratio. Ductules, completely lined by biliary epithelial cells, occupied central regions of hepatic tubules. Relatively elongated, ductular cells were intimately associated with surrounding hepatocytes, separated from them by only a thin extracellular space devoid of a basal lamina. Epithelium of bile ducts included cuboidal through mucus-laden columnar cells, surrounded by basal lamina and, in larger ducts, by fibroblasts, smooth muscle cells, and a capillary plexus. Bile ducts and hepatic arterioles, but not venules, were distributed together. The ultrastructure of biliary epithelium, periductular, and periductal cells is presented.

Mediators of pulmonary injury induced by inhalation of bacterial endotoxin

The purpose of this study has been to further define the pathophysiologic aspects of lung injury caused by the inhalation of endotoxin (LPS) using the morphometric approach to identify mediators that influence distal lung structure and function. Hamsters were divided into 3 groups 24 h prior to low dose LPS inhalation exposure (4 micrograms/m3 for 5 h): (1) pretreated with cobra venom factor to deplete complement in vivo, (2) pretreated with indomethacin to block prostaglandin production, and (3) untreated control group. Both pretreatments abolished LPS-induced decreases in lung volume as well as increases in capillary PMN and platelets seen in untreated control animals. Neither pretreatment had any effect on the LPS-induced decreases of other capillary leukocytes. Similarly, both methods of pretreatment failed to block increases in cellular interstitium of distal capillary septa induced with LPS alone. LPS provoked changes in capillary endothelium, especially seen as an increase in numerical density of endothelial pinocytotic vesicles. Decomplementation failed to alter this increase, but indomethacin pretreatment blocked the effect. Neither treatment had any effect on their size. Low dose LPS inhalation also altered pulmonary capillary permeability to a 125I-BSA probe, which was found in significantly greater amounts in LPS-exposed lungs than in those of saline aerosol control lungs, but was not present in the air space as evidenced by negligible counts in bronchoalveolar lavages. It is evident that endotoxin on the epithelial side of the air-blood barrier leads to changes on the other side of that barrier.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of pulmonary inflammation after endotoxin inhalation with a platelet-activating factor antagonist (48740 RP)

An acute pulmonary response was induced in guinea pigs and hamsters by inhalation of bacterial endotoxin in the form of a purified lipopolysaccharide (LPS). Pretreatment with the platelet-activating factor (PAF) antagonist, 48740 RP, inhibited damage to endothelial cells, decreased vascular permeability and the number of neutrophils in the airways 24 h after exposure to LPS. The increase in the number of platelets in the airways caused by endotoxin was not affected. The results suggest that PAF modulates early inflammation after endotoxin inhalation.

Measurement of superoxide release from single pulmonary alveolar macrophages

An electrooptical method was developed to quantify superoxide (O2-) release from single rat pulmonary alveolar macrophages (PAM) during adherence to the bottom of a culture dish. This was done by measuring the reduction of nitro blue tetrazolium (NBT) to a diformazan precipitate at 550 nm from videorecorded images of individual cells. Temporal changes in cell optical density, which are proportional to the mass of diformazan produced, were calculated from videophotometric measurements of the change in light intensity over individual cells. Total diformazan produced increased 78 and 126% with an increase in NBT from 0.5 to 1.0 and 2.0 mg/ml, respectively. Total diformazan produced and maximum rate of production among individual PAM varied two- to threefold providing strong evidence for heterogeneity in O2- production. Specific inhibition of O2- production by superoxide dismutase, iodoacetate, and chlorpromazine significantly reduced the total diformazan produced and maximum rate of diformazan production. Hydrogen peroxide was not involved in NBT reduction, since catalase alone did not significantly change diformazan production. This novel method to quantify O2- release from single PAM should be valuable in analyzing heterogeneity and single cell kinetics of O2- production, in assessing the effects of exposure of cells to particulates on O2- release, and in relating release to electrophysiological measurements.

Normal versus abnormal structure: considerations in morphologic responses of teleosts to pollutants

Consideration of newer more quantitative morphologic approaches to the study of aquatic pollutants can provide opportunity for collaborative/integrated studies with other subdisciplines in toxicology. Current commonly employed morphologic approaches result largely in subjective findings difficult to analyze statistically and often are directed at levels of structural organization inconsistent with biochemical and physiological approaches. We review some of the methods and approaches available for correlated structure/function studies and present examples from normal and altered skin, gill, and liver of teleosts.

Development of alterations in hamster distal lung following exposure to fly ash from fluidized bed coal combustion: a morphometric study

Fly ash (30 mg) from an experimental fluidized bed coal combustor (FBC) was intratracheally instilled once into male Syrian golden hamsters. At 1, 3, 6, 9, or 30 days postadministration, lungs were fixed by intratracheal perfusion and tissues were processed for light and electron microscopic evaluation. Standard point count morphometry, used to analyze distal lung structures, revealed: an increase in volume density (Vv) of noncellular interstitial space at Day 1 which remained elevated at Day 3 but returned to control values subsequently; increased Vv for polymorphonuclear leukocytes (PMNs) and alveolar macrophages in alveolar air space at Day 6; increased Vv of cellular interstitium at Day 9; and increased Vv of noncellular interstitium at Day 30 following exposure. These observations are consistent with the hypothesis that the primary response of the distal lung to particle exposure is recruitment of PMNs and macrophages. When activated, these cells may release substances affecting the cellular and noncellular composition of the interstitial space, leading eventually to increased connective tissue in the interstitium.

Morphometric changes of the lung induced by inhaled bacterial endotoxin

Due to the ubiquitous nature of airborne endotoxin, an understanding of pulmonary alterations which follow inhalation of environmentally realistic concentrations of purified bacteria derived lipopolysaccharide (LPS) is important. Using LPS derived from Enterobacter agglomerans, a bacterium found in cotton and cotton mill dust, aqueous aerosols (effective LPS concentration 4 micrograms/m3) were generated and used to expose either normal hamsters (N = 6) or those rendered endotoxin tolerant by pre-ip injection of 0.1 LD50 LPS. Control groups (normal--N = 6; tolerant--N = 6) received saline aerosol only. At 6 hr after 5-hr aerosol exposure, lungs of all animals were fixed, processed for light and transmission electron microscopy, and subject to qualitative and to multitiered morphometric analysis using standard point counting techniques. Qualitative evaluation of TEM micrographs from LPS aerosolized-nontolerant hamsters showed endothelial alteration (focal disruption, subendothelial space formation, and cytoplasmic blebbing) but volume and number of endothelial cells were not changed indicating only slight, focal endothelial damage. Quantitatively, septal capillary blood space in nontolerant, LPS aerosolized hamsters showed increased Vv of PMNs and platelets. These changes were not seen in tolerant induced-LPS aerosolized hamsters. Independent of tolerization treatment, LPS inhalation led to a decrease in fixed lung volume and an increase in numerical density of endothelial pinocytotic vesicles. It is concluded that the inhalation of realistic, environmental levels of bacterial endotoxin may induce significant changes in distal lung and may be important in the pathogenesis of byssinosis and adult respiratory distress syndrome.

Pulmonary toxicity associated with fly ash from fluidized bed coal combustion. II. Cellular morphometry of distal lung following a single intratracheal instillation

Fly ash from an experimental fluidized bed coal combustor (FBC) was intratracheally instilled (once) into male Syrian golden hamsters at concentrations of 0 (control), 3, 10, 30, and 100 mg/animal. Thirty days postadministration, lungs were fixed by intratracheal perfusion, and tissues were processed for electron microscopic evaluation. Standard point count morphometry was used to analyze distal lung structures. Significant differences were found in volume density of noncellular interstitial space, with this compartment being increased in a dose-dependent manner. Volume density, numerical density, and average cellular volume of distal lung cells revealed no significant differences between treated and control animals. In addition, diffusion capacity and air-blood barrier thickness were not significantly altered in treated animals. The absence of cellular change at 30 days postexposure suggests a residual effect on noncellular interstitium, which may implicate fibrosis.

Effect of age and exposure to a carcinogen on the structure of the medaka liver: a morphometric study

Morphometric evaluation of liver in the Japanese medaka (Oryzias latipes) was done to define components quantitatively. Analysis was performed in individual fish at: day of hatch (larval), 3-6, and 6-9 months, and 1 year. From analyses of hematoxylin and eosin-stained paraffin sections, the volume densities of hepatocytes, blood vessels (inclusive of sinusoids), intrahepatic bile ducts and ductules, and other components (connective tissue, melanomacrophage centers) were determined. No significant age-related changes were seen. To determine those structural parameters which undergo change 66 and 116 days following a 10-day exposure to methylazoxymethanol acetate (0.5 ppm in water), we performed analyses as above on livers of treated and paired control fish. The stained paraffin sections demonstrated a significant decrease in the volume densities of hepatocytes and blood space and an increase in volume density of bile ducts 66 days after exposure. Although these whole liver values returned toward normal 116 days postexposure, significant alterations in hepatocytes were still seen when toluidine blue-stained semithin sections of Epon-embedded liver were studied. The nuclear-to-cytoplasmic ratio was increased as was stainable material at the cell periphery. The most dramatic change was in the number of hepatocytes per cubic centimeter of liver which was increased by 300% over controls in animals 116 days postexposure. Morphometric data were compared with subjective evaluation at the light and electron microscopic levels.

Ionic content and regulation of cellular volume in rat alveolar type II cells

Alveolar type II epithelial cells were isolated by elastase digestion of rat lungs and purified by centrifugal elutriation. This method yields an enriched fraction of 1 x 10(7) cells/rat containing 85% pure type II pneumocytes. Purified type II cells exhibit a high rate of oxygen consumption, 215 nmol O2 . 10(6) cells-1 . h-1, which is unaffected by the addition of succinate. Type II cells contain 2 microliters H2O/10(7) cells and are approximately 325-330 micrometers 3 in volume. These pneumocytes contain 107 nmol K/l cell H2O and 70 mmol Cl/l cell H2O. In addition, type II cells have a high Na content, i.e., 156 mmol/l cell H2O. However, most of this Na is bound with only 33% being exchangeable. Therefore, the cytoplasmic concentration of free Na is 51 mmol/l cell H2O. Na uptake is very rapid and type II cells i.e., specific activity equilibrium is reached in 15 min with a half time of 5 min. In addition to this large passive transport of Na, type II cells exhibit a highly active Na-K pump involved in the regulation of cellular volume. Volume regulation is inhibited by a decrease in temperature (2 degrees C) and by the addition of ouabain (10(-4) M), Hg (10(-5) M), or Cu (10(-3) M).

Effects of acid-stress on epidermal mucous cells of the brown bullhead Ictalurus nebulosus (LeSeur): a morphometric study

The effects of acid water on alcian blue-periodic acid Schiff's stainable mucosubstances of epidermis from the anterior abdominal wall of brown bullhead catfish, Ictalurus nebulosus, were studied. Standard morphometric techniques were used to determine mucous cell volume density (MCVv) and number density (MCNv) of control (pH 6.8-7.0) and acid-stressed (pH 5.7-6.15) fish. Mucous cell volume density was significantly increased (P less than 0.005) in fish which had been exposed to acid-stress for five days. Since increase in volume density can arise from either an increase in the size of individual mucous cells (hypertrophy), an increase in the number of mucous cell per unit volume (hyperplasia), or a combination of the two, average cell data were computed. No significant difference in cell diameter or cell volume between treated and control groups was seen. However, the number of mucous cells in acid-stressed fish was nearly twice (p less than 0.005) that of controls. These results demonstrated that acid-stress resulted in increased number but not volume of mucous cells (i.e., hyperplasia without hypertrophy).

Ouabain-resistant hyperpolarization induced by insulin in aggregates of embryonic heart cells

Spheroidal aggregates formed from trypsin-dissociated 14-day embryonic chicken hearts after 48 hr of rotation on a gyratory shaker. Intracellularly recorded resting membrane potentials of aggregates bathed in 1.3 mM K+ balanced salt solution had a mean (+/- SD) of 64 +/- 4 mV. After a stable potential was achieved, addition of 1-100 nM sodium bovine insulin caused a slow hyperpolarization of up to 19 mV after 4-5 min, followed, in some cases, by a further, more rapid, shift to a potential near EK. Equivalent hyperpolarizations were observed when insulin was added in the presence of 10 mM ouabain, indicating that enhanced Na+,K+ pump activity was not responsible for the change in membrane potential. The concentration of insulin that produced half-maximal hyperpolarization (2 nM) corresponded to the association constant of a high-affinity insulin receptor, suggesting that binding to this class of receptors led to the change in membrane potential. Steady-state current-voltage curves from current clamp experiments suggested that insulin produced an increase in slope conductance at potentials near rest by inducing an outward current with an apparent potential negative to -90 mV.

Alteration of sensitivity and time scale in invertebrate photoreceptors exposed to anoxia, dinitrophenol, and carbon dioxide

The effects of anoxia, 2,4-dinitrophenol (DNP), and carbon dioxide (CO2) on the late receptor potential of Balanus lateral ocelli, Limulus ventral eyes, and the retinular cells of Linulus lateral eyes have been studied. Either anoxia, DNP, or exposure to 100% CO2 causes a depolarization of 5-30 mV and a gradual reduction and eventually abolition of the late receptor potential and an increase in the latency and time to peak of the response. This lengthening of the time scale is in contrast to the response obtained in photoreceptors that have been light-adapted or injected with calcium. In that case a loss in sensitivity is associated with a decrease in latency and time to peak. Because of these observed differences, the effects of metabolic inhibition cannot be attributed merely to a loss in regulation of intracellular free calcium. Rather, because alteration of intracellular pH (pHi) by using either (NH4)2SO4 or CO2 produced changes in the photoresponse similar to those caused by metabolic inhibition, it is suggested that changes in pHi during metabolic inhibition can account in part for the lengthening of the time scale. In addition to the changes in pHi and internal Ca++ concentration due to metabolic inhibition, the possible role of other consequences of metabolism in the transduction mechanism is also discussed.

Lability of the prolonged depolarizing afterpotential in Balanus photoreceptors

A large cell to cell variability of the prolonged depolarizing afterpotential (PDA) decay time constant (tau) has been measured in Balanus eberneus lateral ocelli. While 25% of the cells had PDA's of long duration, tau greater than 10 min. 45% of the cells tested showed either weak (tau less than 60 s) PDA or none at all. The variability was not reflected in the late receptor potential. All the cells showed normal light-coincident responses. The variability was not due to some alteration of the thermal stability of the pigment states, since after monochromatic adaptation the amplitude of the early receptor potential remained unchanged for at least 30 min. In addition, in some cells that initially showed PDAs of long duration, the decay time was either shortened or abolished after exposure to anoxia. Again, the late receptor potential and the stability of the pigments remained unaffected. These results indicate that the mechanisms which give rise to the PDA are not always tightly coupled to the direct chain of events that lead to the light-coincident response.