Comparative toxicity of trivalent and pentavalent inorganic and methylated arsenicals in rat and human cells

Biomethylation is considered a major detoxification pathway for inorganic arsenicals (iAs). According to the postulated metabolic scheme, the methylation of iAs yields methylated metabolites in which arsenic is present in both pentavalent and trivalent forms. Pentavalent mono- and dimethylated arsenicals are less acutely toxic than iAs. However, little is known about the toxicity of trivalent methylated species. In the work reported here the toxicities of iAs and trivalent and pentavalent methylated arsenicals were examined in cultured human cells derived from tissues that are considered a major site for iAs methylation (liver) or targets for carcinogenic effects associated with exposure to iAs (skin, urinary bladder, and lung). To characterize the role of methylation in the protection against toxicity of arsenicals, the capacities of cells to produce methylated metabolites were also examined. In addition to human cells, primary rat hepatocytes were used as methylating controls. Among the arsenicals examined, trivalent monomethylated species were the most cytotoxic in all cell types. Trivalent dimethylated arsenicals were at least as cytotoxic as trivalent iAs (arsenite) for most cell types. Pentavalent arsenicals were significantly less cytotoxic than their trivalent analogs. Among the cell types examined, primary rat hepatocytes exhibited the greatest methylation capacity for iAs followed by primary human hepatocytes, epidermal keratinocytes, and bronchial epithelial cells. Cells derived from human bladder did not methylate iAs. There was no apparent correlation between susceptibility of cells to arsenic toxicity and their capacity to methylate iAs. These results suggest that (1) trivalent methylated arsenicals, intermediary products of arsenic methylation, may significantly contribute to the adverse effects associated with exposure to iAs, and (2) high methylation capacity does not protect cells from the acute toxicity of trivalent arsenicals.

Acute renal failure associated with increased intra-abdominal pressure

Anuric renal failure developed in four patients in association with increased intra-abdominal pressure from postoperative hemorrhage. Polyuria and resolution of the renal failure occurred in each patient in response to operative decompression of the abdomen. Renal failure secondary to increased intra-abdominal pressure has been previously produced experimentally in dogs by the intraperitoneal installation of graded amounts of saline. This is the first report of this type of renal failure in clinical practice.

Kinetics of fetal cellular and cell-free DNA in the maternal circulation during and after pregnancy: implications for noninvasive prenatal diagnosis

BACKGROUND

Fetal genetic material is detectable in the maternal circulation and has been used for noninvasive prenatal diagnosis. However, few data are available concerning its quantity and natural history during gestation.

STUDY DESIGN AND METHODS

This study prospectively characterized the kinetics of cellular and cell-free fetal DNA in the circulation of 25 healthy women during and after uncomplicated pregnancy. Real-time kinetic PCR was used to quantitate human Y-chromosome sequences, and liquid oligomer hybridization with (32)P-labeled probes was used to verify the identity of amplified products.

RESULTS

In all male pregnancies, but no female pregnancies, low-level fetal Y-chromosome DNA was detected in both cellular and cell-free compartments beginning at 7 to 16 weeks but increasing steadily after 24 weeks and reaching a peak at parturition. The fetal DNA decreased rapidly after birth.

CONCLUSION

Fetal genetic material can be detected throughout pregnancy, and its quantity is a function of gestational age and of whether the plasma or cellular compartment is examined. Both the absolute quantity of fetal DNA and its ratio to total DNA (maternal + fetal) are greater in the plasma than in the cellular compartment. Fetal DNA is cleared rapidly from both compartments after parturition, which suggests that turnover is dynamic. Because they provide prospective and quantitative data concerning fetal DNA levels, these observations and kinetic PCR methods may have implications for noninvasive prenatal diagnosis. Further studies will be needed to determine the immunologic implications of fetal-maternal DNA exchange and cellular microchimerism.

Air pollution particles induce IL-6 gene expression in human airway epithelial cells via NF-kappaB activation

Fine particles in the air have been associated with increased mortality and morbidity. Particulate air pollution is a complex mixture which varies by region and includes a number of components including residual oil fly ash (ROFA), a byproduct of power plant and industry fuel-oil combustion. Human airway epithelial cells exposed to ROFA release inflammatory cytokines including interleukin (IL)-6, IL-8, and tumor necrosis factor. Expression of these genes is dependent upon pretranscriptional binding of cis regulatory elements, including nuclear factor kappaB (NF-kappaB). To investigate the role of NF-kappaB in the particulate-induced IL-6 response, we exposed human airway epithelial cells (BEAS-2B) to ROFA in vitro. ROFA stimulated a time- and dose-dependent increase in IL-6 messenger RNA (mRNA), which was preceded by the activation of nuclear proteins binding to the NF-kappaB sequence motif in the IL-6 promoter. Transient transfection of BEAS-2B cells with the 5' promoter region of the IL-6 gene linked to a luciferase reporter gene confirmed that NF-kappaB binding is necessary for the transcription of IL-6 mRNA. The IL-6 response was inhibited by the metal chelator deferoxamine and the free radical scavenger N-acetyl-L-cysteine, suggesting that the activation of NF-kappaB may be mediated through reactive oxygen intermediates generated by transition metals found in ROFA. Activation of NF-kappaB may therefore be a critical first step in the inflammatory cascade following exposure to particles generated by oil combustion.

Copper-dependent inflammation and nuclear factor-kappaB activation by particulate air pollution

Particulate air pollution causes increased cardiopulmonary morbidity and mortality, but the chemical determinants responsible for its biologic effects are not understood. We studied the effect of total suspended particulates collected in Provo, Utah, an area where an increase in respiratory symptoms in relation to levels of particulate pollution has been well documented. Provo particulates caused cytokine-induced neutrophil chemoattractant-dependent inflammation of rat lungs. Provo particulates stimulated interleukin-6 (IL-6) and IL-8 production, increased IL-8 messenger RNA (mRNA) and enhanced expression of intercellular adhesion molecule-1 (ICAM-1) in cultured BEAS-2B cells, and stimulated IL-8 secretion in primary cultures of human bronchial epithelium. Cytokine secretion was preceded by activation of the transcription factor nuclear factor-kappaB (NF-kappaB) and was reduced by treatment of cultures with superoxide dismutase, deferoxamine, or N-acetylcysteine. These biologic effects were replicated by culturing BEAS cells with quantities of Cu2+ found in Provo extract. IL-8 secretion by BEAS cells could be modified by addition of normal constituents of airway lining fluid to the culture medium. Mucin significantly reduced IL-8 secretion, and ceruloplasmin significantly increased IL-8 secretion and activation of NF-kappaB. These findings suggest that copper ions may cause some of the biologic effects of inhaled particulate air pollution in the Provo region of the United States, and may provide an explanation for the sensitivity of asthmatic individuals to Provo particulates that has been observed in epidemiologic studies.

Omeprazole v ranitidine for prevention of relapse in reflux oesophagitis. A controlled double blind trial of their efficacy and safety

The aim of this study was to compare recurrence rates of reflux oesophagitis (after endoscopic healing with omeprazole) over a 12 month period of randomised, double blind, maintenance treatment with either daily omeprazole (20 mg every morning; n = 53), weekend omeprazole (20 mg on three consecutive days a week, n = 55) or daily ranitidine (150 mg twice daily, n = 51). Patients were assessed for relapse by endoscopy (with gastric biopsy) at six and 12 months, or in the event of symptomatic recurrence, and serum gastrin was monitored. At 12 months, the estimated proportions of patients in remission (actuarial life table method) were 89% when receiving daily omeprazole compared with 32% when receiving weekend omeprazole (difference 57%, p < 0.001, 95% confidence intervals: 42% to 71%) and 25% when receiving daily ranitidine (difference 64%, p < 0.001, 95% confidence intervals: 50% to 78%). Median gastrin concentrations increased slightly during the healing phase, but remained within the normal range and did not change during maintenance treatment. No significant pathological findings were noted, and no adverse events were attributable to the study treatments. In conclusion, for patients who respond favourably to acute treatment with omeprazole 20 mg every morning, the drug is a safe and highly effective maintenance treatment for preventing relapse of reflux oesophagitis and its associated symptoms over 12 months. By contrast, weekend omeprazole and daily ranitidine were ineffective.

Four-coordinate iron complexes bearing α-diimine ligands: efficient catalysts for Atom Transfer Radical Polymerisation (ATRP)

Four-coordinate iron(II) complexes bearing alpha-diimine ligands with alkyl substituents are shown to be efficient catalysts for the well-controlled atom transfer radical polymerisation of styrene; catalysts containing aryldiimine ligands support competitive beta-hydrogen chain transfer processes.

Activation of MAPKs in human bronchial epithelial cells exposed to metals

We have previously shown that in vitro exposure to metallic compounds enhances expression of interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha in human bronchial epithelial cells. To characterize signaling pathways involved in metal-induced expression of inflammatory mediators and to identify metals that activate them, we studied the effects of As, Cr, Cu, Fe, Ni, V, and Zn on the mitogen-activated protein kinases (MAPK) extracellular receptor kinase (ERK), c-Jun NH2-terminal kinase (JNK), and P38 in BEAS cells. Noncytotoxic concentrations of As, V, and Zn induced a rapid phosphorylation of MAPK in BEAS cells. Activity assays confirmed marked activation of ERK, JNK, and P38 in BEAS cells exposed to As, V, and Zn. Cr and Cu exposure resulted in a relatively small activation of MAPK, whereas Fe and Ni did not activate MAPK under these conditions. Similarly, the transcription factors c-Jun and ATF-2, substrates of JNK and P38, respectively, were markedly phosphorylated in BEAS cells treated with As, Cr, Cu, V, and Zn. The same acute exposure to As, V, or Zn that activated MAPK was sufficient to induce a subsequent increase in IL-8 protein expression in BEAS cells. These data suggest that MAPK may mediate metal-induced expression of inflammatory proteins in human bronchial epithelial cells.

Multiple neuropeptides in cholinergic motor neurons of Aplysia: evidence for modulation intrinsic to the motor circuit

Changes in Aplysia biting responses during food arousal are partially mediated by the serotonergic metacerebral cells (MCCs). The MCCs potentiate contractions of a muscle utilized in biting, the accessory radula closer (ARCM), when contractions are elicited by stimulation of either of the two cholinergic motor neurons B15 or B16 that innervate the muscle. We have now shown that ARCM contractions may also be potentiated by peptide cotransmitters in the ARCM motor neurons. We found that motor neuron B15 contains small cardioactive peptides A and B (SCPA and SCPB)--i.e., whole B15 neurons were bioactive on the SCP-sensitive Helix heart, as were reverse-phase HPLC fractions of B15 neurons that eluted like synthetic SCPA and SCPB. Furthermore, [35S]methionine-labeled B15 peptides precisely coeluted with synthetic SCPA and SCPB. SCPB-like immunoreactivity was associated with dense-core vesicles in the soma of B15 and in neuritic varicosities and terminals in the ARCM. B16 motor neurons did not contain SCPA or SCPB but contained an unidentified bioactive peptide. RP-HPLC of [35S]methionine-labeled B16s resulted in one major peak of radioactivity that did not coelute with either SCP and which, when subject to Edman degradation, yielded [35S]methionine in positions where there is no methionine in the SCPs. Exogenously applied B16 peptide potentiated ARCM contractions elicited by stimulation of B15 or B16 neurons. Thus, in this system there appear to be two types of modulation; one type arises from the MCCs and is extrinsic to the motor system, whereas the second type arises from the motor neurons themselves and hence is intrinsic.

The prognostic value of p53 and c-erb B-2 immunostaining is overrated for patients with lymph node negative breast carcinoma: a multivariate analysis of prognostic factors in 613 patients with a follow-up of 14-30 years

BACKGROUND

Approximately 30% of breast carcinoma patients with negative lymph nodes die of their disease. Biologic markers such p53 protein and c-erb B-2 have been related to tumor progression, but their prognostic value remains controversial.

METHODS

Two large series of a total of 613 lymph node negative breast carcinoma patients from a single institution were analyzed with respect to tumor size, histologic grade, and immunohistochemical staining for p53, c-erb B-2, estrogen receptor (ER), and progesterone receptor (PgR). Interobserver variation in histologic grading was evaluated by Kappa statistics. The two series had different treatment modalities: 228 patients (SACGS group) were treated surgically with mastectomy and given 1 perioperative chemotherapy course, and 385 patients (HOST group) were treated with mastectomy and ovarian radiation and further randomized to receive postoperative treatment with radiotherapy or no adjuvant treatment. The follow-up ranged from 14-30 years.

RESULTS

Immunoreactivities for p53, c-erb B-2, ER, and PgR did not differ significantly in the two series. p53 immunostaining was present in 187 of 613 tumors (29%), and c-erb B-2 immunoreactivity was present in 58 of the tumors (10%). Three hundred forty-eight tumors (57%) were positive for ER. Kappa statistics value of interobserver variation in the histologic grading of ductal carcinomas was 0.69, which is considered to be a substantial degree of agreement. No significant differences in survival were found when comparing p53, c-erb B-2, ER, and PgR positive and negative cases. However, both recurrence free survival rates and overall survival rates after 10 years were significantly better in the T1N0M0 group compared with the T2N0M0 group (81% vs. 67% [P < 0.0001] and 85% vs. 70% [P < 0.0001]). Ten-year recurrence free survival rates for patients with histologic Grade 1 versus Grades 2-3 (according to Elston and Ellis' modification of the Bloom and Richardson method) tumors were 90% and 70%, respectively (P < 0. 0001), and overall survival rates for the same groups were 94% and 81%, respectively (P=0.0002). After 30 years of follow-up, the overall survival rate for patients with tumors of histologic Grade 1 versus Grades 2-3 were 87% and 68%, respectively, and were 78% and 66%, respectively, for patients with tumors </= 2 mm versus those with tumors > 20-50 mm. Approximately 35% of the patients with tumors of histologic Grades 2-3 and measuring > 20 mm were dead after 10 years of follow-up, contrary to 6% of the patients with tumors of histologic Grade 1 measuring </= 20 mm. A significantly more favorable prognosis also was observed in patients in the HOST group treated with adjuvant radiotherapy.

CONCLUSIONS

Histologic grade and tumor size were found to be major prognostic factors for patients after 30 years of follow-up. c-erb B-2 and p53 immunostaining does not appear have any independent prognostic value. Adjuvant radiotherapy may be of value in the treatment of patients with localized tumors.

Macrophage cytoskeleton association with CR3 and CR4 regulates receptor mobility and phagocytosis of iC3b-opsonized erythrocytes

Alveolar macrophages (AM phi) were examined for CR1 (C3b receptor, CD35), CR3 (iC3b receptor; CD11b/CD18), and CR4 (iC3b receptor; CD11c/CD18) by assays for binding of C3-opsonized sheep erythrocytes (EC3b or EC3bi) and uptake of specific monoclonal antibodies (mAbs). In AM phi isolates from nine normal volunteers, 49% of cells bound EC3b and 71% bound EC3bi. Quantitation of receptors per cell with [125I]mAbs showed 8.5 x 10(4) CR4, 5.1 x 10(4) CR3, and 2.6 x 10(4) CR1. With most AM phi preparations, CR3 was the major receptor mediating attachment of EC3bi, despite the predominance of CR4 antigens. Anti-CR3 inhibited EC3bi rosettes by > or = 50%, whereas anti-CR4 blocked rosettes by < or = 18%. U937 cells differentiated with phorbol myristate acetate resembled AM phi in receptor expression but exhibited almost no CR4-dependent rosetting. Despite the relative inability of CR4 to mediate EC3bi attachment, AM phi ingestion of [51Cr]EC3bi was blocked by either anti-CR3 or anti-CR4. Two lines of evidence indicated that CR3 were more mobile within the membrane than were CR4. Immunofluorescence staining demonstrated patching and occasional capping of CR3, whereas CR4 remained uniformly distributed. This patching and capping of CR3 required the actin cytoskeleton, as it was inhibited by cytochalasin D. Modulation experiments using surfaces coated with anti-CR3 or anti-CR4 also showed that CR3 was more mobile than was CR4. However, there was some variation among AM phi isolates from different donors. In seven isolates, no CR4 modulation was produced with anti-CR4, whereas in six other isolates, CR4 was modulated by 66%. Incubation of cells in cytochalasin D increased modulation of both CR3 and CR4 on mAb-coated surfaces. Cells exhibiting increased mobility of CR4 showed an increased ability to form CR4-dependent EC3bi rosettes. The data are consistent with the hypothesis that CR3 and CR4 exhibit a variable association with the cytoskeleton that regulates their mobility and function. A relatively mobile subset of CR3 and/or CR4 mediates EC3bi attachment, whereas a relatively immobile subset of CR3 and/or CR4 fails to mediate EC3bi attachment but functions to promote ingestion of EC3bi.

Hydrogen peroxide has opposing effects on IKK activity and IkappaBalpha breakdown in airway epithelial cells

Recent studies have advanced our knowledge about the signal transduction cascade involved in the activation of nuclear factor (NF) kappaB, including the identification and characterization of IkappaB kinases (IKKs). Although exposure to hydrogen peroxide (H2O2) in vitro can activate NF-kappaB, this response is not universal and depends on the cell type and transformation state. In this study, we examined the effects of H2O2 on IKKs and activation of NF-kappaB in primary normal human bronchial epithelial (NHBE) cells. Our results demonstrate that treatment with H2O2 increased IKK activity, phosphorylation, and ubiquitination of IkappaBalpha in NHBE cells. However, there was no significant proteolytic degradation of IkappaBalpha, nuclear translocation of p65, or NF-kappaB DNA binding activity in cells treated with H2O2. Treatment with H2O2 also inhibited tumor necrosis factor (TNF)-alpha-induced IkappaBalpha breakdown, NF-kappaB DNA binding activity, and NF-kappaB-dependent transcription but had no effect on TNF-alpha-induced IkappaBalpha phosphorylation or ubiquitination. Furthermore, treatment with H2O2 alone or in combination with TNF-alpha increased the levels of other ubiquitinated proteins in NHBE cells, suggesting general inhibition of proteasomal activity by H2O2. Taken together, these results demonstrate that in airway epithelial cells treatment with H2O2 has opposing effects on IKK activity and proteasomal degradation of IkappaBalpha, and suggest that H2O2 may suppress TNF-alpha-induced NF-kappaB- dependent gene expression.

CD14-dependent airway neutrophil response to inhaled LPS: role of atopy

BACKGROUND

Inhaled endotoxin (LPS) is associated with airway neutrophilic (PMN) inflammation in both asthmatic and control subjects, with asthmatic subjects demonstrating possibly higher sensitivity. CD14 is the principal receptor mediating LPS responses in vivo. It is unknown whether constitutive CD14 can predict the magnitude of the PMN response after LPS inhalation and whether atopy plays a role in this response.

OBJECTIVE

We sought to examine associations between constitutive airway CD14 expression and LPS-induced PMNs after 5 microg of LPS inhalation and to examine associations between markers of atopy (eosinophils and eosinophil cationic protein) and CD14 expression and LPS-induced PMNs.

METHODS

Ten atopic asthmatic subjects and 8 healthy control subjects inhaled 0.9% saline and LPS (Escherichia coli 026:B6, 5 microg) separated by 3 weeks. Induced sputum was collected at 24 hours before and 6 hours after inhalation. Induced sputum was analyzed for total and differential cell counts and soluble markers (soluble [s]CD14, eosinophil cationic protein, IL8, and total protein). Flow cytometry was used to analyze membrane-bound CD14 expression.

RESULTS

Significant associations were found between the LPS-induced PMN response (PMNs per milligram of sputum) and both constitutive sCD14 (R = 0.7, P =.005) and membrane-bound CD14 (R = 0.9, P =.01). Asthmatic subjects demonstrated significantly higher levels of constitutive sCD14 compared with control subjects, and baseline eosinophils were significantly associated with baseline sCD14 (R = 0.7, P =.01) and LPS-induced PMNs (R = 0.6, P =.03).

CONCLUSION

Constitutive airway CD14 expression can predict the magnitude of the PMN response after inhaled LPS. Atopy appears to play a role in the level of CD14 expression and may contribute to LPS sensitivity in asthmatic subjects.

Transferrin Index: An Alternative Method for Calculating the Iron Saturation of Transferrin

We surveyed 140 clinical chemistry laboratories in Australia to establish which laboratory methods they used to determine serum iron status: 125 measured serum iron (Fe), 85 measured transferrin (TRF), 47 measured total iron-binding capacity (TIBC), and 14 measured both TRF and TIBC. Of the 55 laboratories routinely reporting TRF saturation (TS), 16 calculated TS directly as (Fe/TIBC) x 100, and 9 used [Fe/(TRF x 2)] x 100. Thirty laboratories measured TRF and converted it to an equivalent TIBC concentration; the derived TIBC was then used to calculate TS. We measured iron, TIBC, and TRF concentrations in 94 control subjects, 59 patients with alcoholic liver disease (ALD), and 20 with proven genetic hemochromatosis (GH). TS was compared with a transferrin index (TI = Fe/TRF) to determine whether both methods were sensitive for GH screening and which method gave the fewest false-positive results with discrimination limits of &gt; 55% and &gt; 1.0, respectively. All GH patients were detected by both TS and TI at these limits. One control subject had a TI &gt; 1.0, whereas three control subjects had a TS &gt; 55%. Nine patients with ALD had a TI &gt; 1.0 and 11 ALD patients had a TS &gt; 55%. Some iron-overload patients had lower than expected TS values compared with TI, possibly because of ferritin interference in the TIBC assay. Also, the precision of the TRF assay was better than that of the TIBC assay: CVs of 1.85-3.68% vs 6.17%. We therefore recommend that calculated TI replace TS in screening for iron overload.

Pregnancy and breast cancer: a population-based study

The incidence of pregnancy-associated breast cancer, i.e. during pregnancy and lactation, and of pregnancy subsequent to a breast-cancer diagnosis will increase as more women choose childbearing at a later age. Few larger series are published on pregnancy-associated breast cancer. In a population-based study, we evaluated the outcome and prognostic factors in 173 breast-cancer patients. One hundred and twenty-two patients had pregnancy-associated breast cancer (20 coincident with pregnancy and 102 during lactation) and 51 patients had pregnancy subsequent to breast cancer. The median follow-up time was 151 months. Histopathological parameters and immunoreactivity for oestrogen and progesterone receptors c-erbB-2 and c-erbB-4 were studied. All three groups had tumours with high histological grade, low frequency of hormone receptors and high expression of c-erbB-2. The pregnancy and lactation groups were near identical with regard to all histopathological parameters and outcome. In the two pregnancy-associated breast-cancer groups, tumours were significantly larger, with more extensive lymph-node involvement. For node-negative tumours the respective 5- and 10-year survival rates were 62% and 50% in the pregnancy group and 60% and 50% in the lactation group. For node-positive tumours, respective 5- and 10-year survival rates were 50% and 34% in the pregnancy group and 50% and 33% in the lactation group. In the subsequent group, overall survival was high in both node-negative and -positive groups, with 5- and 10-year survival rates of 80% and 73% and 86% and 76%, respectively. Tumour size, lymph-node status, histological grade, progesterone receptor, oestrogen receptor and c-erbB-2 were significant prognostic factors in the pregnancy-associated breast-cancer patients.

RSV infection of human airway epithelial cells causes production of the beta-chemokine RANTES

Infection of airway epithelial cells with respiratory syncytial virus (RSV) results in the production of a restricted number of cytokines, which may modulate the inflammatory response to infection. To get a better understanding of epithelial cell-mediated inflammatory processes in RSV disease, the aim of the present study was to identify the production of mononuclear cell/eosinophil/mast cell inflammatory chemokines [monocyte chemotactic protein (MCP)-1, MCP-3, macrophage inflammatory protein-1beta, and RANTES] during productive RSV infection in airway epithelial cells. Normal human primary bronchial epithelial cell cultures, nasal epithelial cell explants, and the BEAS-2B airway epithelial cell line were inoculated with RSV, and chemokine induction was assessed during the phase of logarithmic increase in infectious virus production. Only RANTES was found to increase in epithelial cell cultures in an infection-dependent manner. Furthermore, RANTES was released only by RSV-producing cells. To determine whether RANTES was induced by RSV infection in vivo, RANTES was measured in nasal lavage fluids (NLF) from children with RSV-positive and RSV-negative upper respiratory infection and children when they were well. RANTES was increased significantly during RSV infection (128 +/- 38 pg/ml NFL) compared with non-RSV infection (42 +/- 12 pg/ml NFL) and with asymptomatic baseline (13 +/- 4 ng/ml NFL) in the same children. Because RANTES is an effective eosinophil and memory T cell chemoattractant and activator and because eosinophil-dominated inflammation is a hallmark of asthmatic airways, RANTES may play a role in the pathogenesis of RSV-induced exacerbations of airway reactivity and wheezing.

Activation of the EGF receptor signaling pathway in human airway epithelial cells exposed to metals

We have previously shown that exposure to combustion-derived metals rapidly (within 20 min) activated mitogen-activated protein kinases (MAPK), including extracellular signal-regulated kinase (ERK), in the human bronchial epithelial cell line BEAS. To study the mechanisms responsible for metal-induced activation of ERK, we examined the effect of noncytotoxic exposures to As, Cu, V, or Zn on the kinases upstream of ERK in the epidermal growth factor (EGF) receptor signaling pathway. Western blotting using phospho-specific ERK1/2 antibody demonstrated the selective MEK1/2 inhibitor PD-98059 blocked metal-induced phosphorylation of ERK1/2. Meanwhile, Western blotting using a phospho-specific MEK1/2 antibody showed that these metals induce a rapid phosphorylation of MEK1/2. Kinase activity assays confirmed the activation of MEK1/2 by metal treatment. Immunoprecipitation studies demonstrated that As, Cu, V, or Zn induces EGF receptor phosphorylation. Furthermore, the EGF receptor-specific tyrosine kinase inhibitor (PD-153035) significantly blocked the phosphorylation of MEK1/2 initiated by metals. Interestingly, we observed low levels of Raf-1 activity that were not increased by metal exposure in these cells through kinase activity assay. Finally, transfection assays showed that MEK1/2 inhibition could inhibit trans-activation of Elk1, a transcription factor in the ERK pathway, in BEAS cells exposed to metals. Together, these data demonstrate that As, Cu, V, and Zn can activate the EGF receptor signaling pathway in BEAS cells and suggest that this mechanism may be involved in pulmonary responses to metal inhalation.

Computerized measurement of iron in liver biopsies: a comparison with biochemical iron measurement

The measurement of stainable hepatic iron using a microcomputer image analysis system was compared with standard biochemical measurements of liver iron content in 103 liver biopsy specimens--29 of idiopathic hemochromatosis, 51 of alcoholic liver disease and 23 of various nonalcoholic liver diseases. Sections were stained using Perls' method for iron; the mean area staining positively for iron was measured and expressed as a percentage of the area of biopsy measured. Biochemical (biochemical hepatic iron [mumol/gm dry wt]/age) and morphometrical (morphometrical hepatic iron [%]/age x 100) hepatic iron indices were calculated. Patients in the idiopathic hemochromatosis group had significantly higher biochemical hepatic iron concentrations (p less than 0.001) compared with the alcoholic liver disease and nonalcoholic liver disease groups: 284 (range = 119 to 631), 21 (range = 2 to 65) and 15 (range = 3 to 31) mumol/gm dry wt, respectively. The biochemical hepatic iron index was also significantly higher (p less than 0.001) in the hemochromatosis group compared with the alcoholic liver disease and nonalcoholic liver disease groups: 5.8 (range = 2.1 to 13.7), 0.4 (range = 0 to 1.6) and 0.4 (range = 0 to 1.1), respectively. Computerized measurements were significantly higher in the hemochromatosis group (p less than 0.001) compared with the alcoholic liver disease and nonalcoholic liver disease groups: 9.72% (range = 1.50% to 29.26%), 0.13% (range = 0% to 1.20%) and 0.03% (range = 0% to 0.40%), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Eosinophil influx to the nasal airway after local, low-level LPS challenge in humans

BACKGROUND

Recent observations show that atopic asthmatic subjects have increased sensitivity to respirable endotoxin (or LPS) compared with normal persons. In vitro studies demonstrate that LPS enhances eosinophil survival. These observations suggest that the effects of inhaled LPS in asthmatic subjects may include increases in the number of airway eosinophils.

OBJECTIVE

We sought to determine whether low-level nasal LPS challenge causes an increase in eosinophil numbers in the nasal airways of atopic or normal subjects.

METHODS

Sixteen volunteers (10 atopic asthmatic subjects and 6 normal subjects) underwent 2 nasal challenge sessions. In one session, one nostril was challenged with saline and the other with 0. 1 microg of LPS. During the second session, 0.3 microg and 1.0 microg of LPS was delivered to each nostril, respectively. Nasal lavage fluid was obtained from each nostril before challenge, as well as 4 and 24 hours after challenge, and examined for the percent of total cells that were eosinophils and neutrophils, as well as cytokine levels.

RESULTS

LPS (1.0 microg) increased the percent of eosinophils in nasal lavage fluid 4 hours after challenge in atopic subjects only. There was also a correlation between constitutive nasal GM-CSF and eosinophil response to LPS in atopic subjects.

CONCLUSION

LPS challenge increases eosinophils in the airways of atopic subjects.

Vanadium-induced kappaB-dependent transcription depends upon peroxide-induced activation of the p38 mitogen-activated protein kinase

Activation of nuclear factor (NF)-kappaB and subsequent proinflammatory gene expression in human airway epithelial cells can be evoked by oxidative stress. In this study we examined signal transduction pathways activated by vanadyl sulfate (V(IV))-induced oxidative stress in normal human bronchial epithelial cells. Both nuclear translocation of NF-kappaB and enhanced kappaB-dependent transcription induced by V(IV) were inhibited by overexpression of catalase, but not Cu,Zn superoxide dismutase (Cu,Zn-SOD), indicating that peroxides rather than superoxides initiated signaling. Catalase selectively blocked the response to V(IV) because it inhibited neither NF-kappaB translocation nor kappaB-dependent transcription evoked by the proinflammatory cytokine tumor necrosis factor (TNF)-alpha. The V(IV)-induced kappaB-dependent transcription was dependent upon activation of the p38 mitogen-activated protein kinase because overexpression of dominant-negative mutants of the p38 MAPK pathway inhibited V(IV)-induced kappaB-dependent transcription. This inhibition was not due to suppression of NF-kappaB nuclear translocation because NF-kappaB DNA binding was unaffected by the inhibition of p38 activity. Overexpression of catalase, but not Cu,Zn-SOD, inhibited p38 activation, indicating that peroxides activated p38. Catalase failed to block V(IV)- induced increases in phosphotyrosine levels, suggesting that the catalase-sensitive signaling components were independent of V(IV)-induced tyrosine phosphorylation. The data demonstrate that V(IV)-induced oxidative stress activates at least two distinct pathways, NF-kappaB nuclear translocation and p38-dependent transactivation of NF-kappaB, both of which are required to fully activate kappaB-dependent transcription. Moreover, V(IV)-induced oxidative stress activated these pathways in bronchial epithelial cells by upstream signaling cascades that were distinct at some level from those used by the proinflammatory cytokine TNF-alpha.

Arsenite exposure of cultured airway epithelial cells activates kappaB-dependent interleukin-8 gene expression in the absence of nuclear factor-kappaB nuclear translocation

Airway epithelial cells respond to certain environmental stresses by mounting a proinflammatory response, which is characterized by enhanced synthesis and release of the neutrophil chemotactic and activating factor interleukin-8 (IL-8). IL-8 expression is regulated at the transcriptional level in part by the transcription factor nuclear factor (NF)-kappaB. We compared intracellular signaling mediating IL-8 gene expression in bronchial epithelial cells cultured in vitro and exposed to two inducers of cellular stress, sodium arsenite (As(III)), and vanadyl sulfate (V(IV)). Unstimulated bronchial epithelial cells expressed IL-8, and exposure to both metal compounds significantly enhanced IL-8 expression. Overexpression of a dominant negative inhibitor of NF-kappaB depressed both basal and metal-induced IL-8 expression. Low levels of nuclear NF-kappaB were constitutively present in unstimulated cultures. These levels were augmented by exposure to V(IV), but not As(III). Accordingly, V(IV) induced IkappaBalpha breakdown and NF-kappaB nuclear translocation, whereas As(III) did not. However, both As(III) and V(IV) enhanced kappaB-dependent transcription. In addition, As(III) activation of an IL-8 promoter-reporter construct was partially kappaB-dependent. These data suggested that As(III) enhanced IL-8 gene transcription independently of IkappaB breakdown and nuclear translocation of NF-kappaB in part by enhancing transcription mediated by low levels of constitutive nuclear NF-kappaB.

Immunohistology is valuable in distinguishing between Paget's disease, Bowen's disease and superficial spreading malignant melanoma

Thirty-nine lesions, originally diagnosed as Paget's disease (19), superficial spreading melanoma (13) or Bowen's disease (7), were reviewed. Supplementary immunohistochemistry on routine processed tissue, using antibodies to cytokeratins (PKK1 and M717) and to S-100 protein, was carried out. Two of the lesions, originally classified as Bowen's disease and superficial spreading type malignant melanoma respectively, were reclassified as Paget's disease based on the immunohistochemical findings. Both lesions contained pagetoid cells positive with PKK1. The results indicate that immunohistochemistry may sometimes be valuable in establishing the correct diagnosis in such lesions.