Local excision and treatment of early node-negative anal squamous cell carcinomas in a highly HIV prevalent population.

BACKGROUND: Anal squamous cell carcinoma (ASCC) is an uncommon cancer associated with human immunodeficiency virus (HIV) infection. There has been increasing interest in providing organ-sparing treatment in small node-negative ASCC's, however, there is a paucity of evidence about the use of local excision alone in people living with HIV (PLWH). The aim of this study was to evaluate the efficacy of local excision alone in this patient population. METHODS: We present a case series of stage 1 and stage 2 ASCC in PLWH and HIV negative patients. Data were extracted from a 20-year retrospective cohort study analysing the treatment and outcomes of patients with primary ASCC in a cohort with a high prevalence of HIV. RESULTS: Ninety-four patients were included in the analysis. Fifty-seven (61%) were PLWH. Thirty-five (37%) patients received local excision alone as treatment for ASCC, they were more likely to be younger (p = 0.037, ANOVA) and have either foci of malignancy or well-differentiated tumours on histology (p = 0.002, Fisher's exact test). There was no statistically significant difference in 5-year disease-free survival and recurrence between treatment groups, however, patients who had local excision alone and PLWH were both more likely to recur later compared to patients who received other treatments for ASCC. (72.3 months vs 27.3 months, p = 0.06, ANOVA, and 72.3 months vs 31.8 months, p = 0.035, ANOVA, respectively). CONCLUSIONS: We recommend that local excision be considered the sole treatment for stage 1 node-negative tumours that have clear margins and advantageous histology regardless of HIV status. However, PLWH who have local excision alone must have access to an expert long-term surveillance programme after treatment to identify late recurrences.

Seroprevalence of Aspergillus IgG and disease prevalence of chronic pulmonary aspergillosis in a country with intermediate burden of tuberculosis: a prospective observational study.

OBJECTIVES: Chronic pulmonary aspergillosis (CPA) is an emerging global disease with tuberculosis (TB) being the most important risk factor. Epidemiologic data on the seroprevalence of Aspergillus IgG and prevalence of CPA in different areas, especially in country with intermediate burden of TB, are lacking. METHODS: We prospectively recruited healthy volunteers, TB close contacts, active TB patients and participants with old pulmonary TB in Taiwan during 2012-2019. We measured serum Aspergillus fumigatus and niger-specific IgG levels and assessed if the participants were having CPA. RESULTS: A total of 1242 participants (including 200 healthy volunteers, 326 TB close contacts, 524 active TB patients and 192 old TB cases) were recruited. Using 27 mgA/L (milligrams of antigen-specific antibodies per liter) as cut-off level, the seropositive rate of A. fumigatus-specific IgG was 33.0% (66/200), 37.7% (123/326), 26.5% (139/524) and 43.2% (83/192) among the four groups, respectively. In multivariate logistic regression, pulmonary cavitation (OR 1.73; 95% CI 1.07-2.80), female sex (OR 1.49; 95% CI 1.14-1.95), old TB (OR 1.59; 1.05-2.42) were independent risk factors for Aspergillus IgG positivity. One (0.2%) active TB patient and four (2.1%) old TB patients developed CPA. Correlation between A. fumigatus and A. niger-specific IgG was high (Spearman correlation coefficient: 0.942). DISCUSSION: Geographic variation in Aspergillus IgG seroprevalence and CPA prevalence exists. A universal cut-off value for Aspergillus IgG may not exist. In areas and populations in which background Aspergillus IgG level is unknown, Aspergillus IgG may be better used as a test of exclusion for CPA using prespecified cut-off level.

Characterization of Corneal Biomechanical Properties and Determination of Natural Intraocular Pressure Using CID-GAT.

PURPOSE: The intraocular pressure (IOP) measured using Goldmann Applanation Tonometry (GAT) is confounded by individual corneal properties. We investigated a modified method that removes the confoundment by incorporating corneal properties into the Imbert-Fick's law is investigated. METHOD: Porcine eyes were pressurized between 10 and 40 mm Hg using a manometer. The eyes were indented using a flat cylindrical indenter. A modified corneal indentation device (CID) procedure was used to obtain the corneal moduli Eqs . The calculated IOPNC from the Imbert-Fick's Law using the corneal moduli Eqs was compared to the natural IOPN, measured using pressure sensor inserted into the eye. RESULTS: Test results showed that IOP-dependent corneal modulus Eqs is a primary confounding factor in IOP calculation. The average elastic modulus Eqs is 0.173 ± 0.018 MPa at 20 mm Hg, and increases with IOP at a linear rate of 0.0066 MPa per mm Hg (r = 0.997, P < 0.001). Incorporation of individual Eqs into IOPNC calculation showed that IOPNC are in good agreement with reference IOPN (slope = 0.999, r = 0.939, P < 0.001). CONCLUSIONS: The IOP-dependent corneal modulus Eqs is a primary confounding factor in IOP calculation. A modified CID-GAT procedure to obtain natural cornea-independent IOPNC is developed and verified in this study. The CID-GAT IOP modification may be used in place of conventional GAT when the confounding effects in eyes with atypical cornea (e.g., laser-assisted in situ keratomileusis [LASIK] thinned) are significant. TRANSLATIONAL RELEVANCE: Confoundment from corneal properties results in IOP measurement errors. The study showed that the CID-GAT method can significantly reduce the confounding corneal errors.

Session 3: Intra-operative radiotherapy - creating new surgical boundaries.

In patients with advanced and recurrent colorectal cancer, surgical resection with clear margins is the greatest challenge and is limited by known anatomical constraints. Preoperative or intra-operative assessment of the limits of surgical dissection may help to explore the possibility of improving resectability through either targeted external beam radiotherapy or intra-operative radiotherapy. Professor Chang reviews the evidence base and potential advantages and disadvantages of this approach, whilst the expert panel agree a consensus on the evidence for assessment and therapy of such patients.

Session 3: Boosting primary and recurrent rectal cancer: how far can we push the radiotherapy envelope?

Neoadjuvant pelvic radiotherapy is widely used for patients with advanced rectal cancer. The trade-off between dose and response is well-established, yet little consensus remains on the precise methods of delivery and doses given in different scenarios. Professor Vuong reviews the evidence base and trial evidence on the escalation of radiotherapy dose and the methods of achieving this.

Pre-treatment haemoglobin and peripheral blood lymphocyte count as independent predictors of outcome in carcinoma of cervix.

AIMS: To evaluate pre-treatment haemoglobin and peripheral blood lymphocyte (PBL) counts as predictors of treatment outcome in cervix carcinoma treated with radical chemoradiation. MATERIALS AND METHODS: Pre-treatment PBL counts and haemoglobin concentrations were retrieved from full blood count examinations from 111 patients who received concurrent chemoradiotherapy. Overall survival and relapse-free survival were obtained using the Kaplan-Meier method by ranking the data by median haemoglobin and PBL, singly and then in association. Their independence and significance as predictors of outcome were analysed using the Cox proportional hazard model. RESULTS: Survival rates were significantly higher in patients whose haemoglobin level or PBL counts were at or above the corresponding median value. At 5 years, rates of overall survival were 77% versus 41% (P = 0.0003) and 75% versus 42% (P = 0.002), when dichotomised around median haemoglobin and PBL, respectively. In multivariate and univariate analyses, both PBL and haemoglobin were independent and significant predictors for risk of death and relapse. Their predictive power was dramatically enhanced when the data were stratified into four groups by associating patients with haemoglobin ≥ median or < median with those whose PBL was ≥ or < median. CONCLUSION: Baseline PBL and haemoglobin seem to be strong, independent predictors of treatment outcome in carcinoma of the cervix, particularly if patient response is ranked using the predictors simultaneously. The hypothesis needs to be tested and, if confirmed, the markers should be used in combination to identify those at greater risk of failure who may benefit from additional therapy, with further validation in prospective trials offering treatment modification.

Identification of novel determinants of resistance to lapatinib in ERBB2-amplified cancers.

The gene encoding the receptor tyrosine kinase ERBB2, also known as HER2, is amplified and/or overexpressed in up to 15% of breast cancers. These tumours are characterised by an aggressive phenotype and poor clinical outcome. Although therapies targeted at ERBB2 have proven effective, many patients fail to respond to treatment or become resistant and the reasons for this are still largely unknown. Using a high-throughput functional screen we assessed whether genes found to be recurrently amplified and overexpressed in ERBB2+ve breast cancers mediate resistance to the ERBB2-targeted agent lapatinib. Lapatinib-resistant ERBB2-amplified breast cancer cell lines were screened, in the presence or absence of lapatinib, with an RNA interference library targeting 369 genes recurrently amplified and overexpressed in both ERBB2-amplified breast cancer tumours and cell lines. Small interfering RNAs targeting a number of genes caused sensitivity to lapatinib in this context. The mechanisms of resistance conferred by the identified genes were further investigated and in the case of NIBP (TRAPPC9), lapatinib resistance was found to be mediated through NF-κB signalling. Our results indicate that specific amplified and/ or overexpressed genes found in ERBB2-amplified breast cancer may mediate response to ERBB2-targeting agents.

The influence of YMDD mutation patterns on clinical outcomes in patients with adefovir add-on lamivudine combination treatment.

BACKGROUND/AIM: The aim of this study was to assess the patterns of lamivudine (LAM)-resistant mutations and the influence on biochemical and virological responses to adefovir (ADV) add-on LAM combination therapy in patients with LAM-resistant chronic hepatitis B (CHB). METHODS: Seventy-eight CHB patients with confirmed genotypic resistance to LAM, who initiated ADV add-on LAM combination treatment, were enrolled at our institution between April 2007 and April 2009. RESULTS: The baseline tyrosine-methionine-aspartate-aspartate (YMDD) mutation patterns were as follows: rtM204I 45 (57.7%); and rtM204V + rtM204I/V 33 (42.3%). The decrease in the mean ± standard deviation (SD) serum log(10) HBV-DNA level did not differ between the patients carrying the rtM204I vs. rtM204IV +rtM204I/V mutations at 3, 6 and 12 months after the initiation of ADV add-on LAM combination treatment. The proportion of patients who achieved ALT normalization (<40 IU/L) 12 months after the initiation of ADV add-on LAM combination treatment were significantly higher in patients with a rtM204I mutation than rtM204V+ rtM204I/V mutations (39 [86.7%] vs. 22 [66.7%], P = 0.05). The proportion of patients in whom the log(10) HBV-DNA decreased <2 log(10) copies/ml, 6 months after the initiation of ADV add-on LAM combination treatment (non-responders), was significantly higher in patients with a rtM204V + rtM204I/V mutations than rtM204I mutation (7 [21.2%] vs. 2 [4.4%], P = 0.032). CONCLUSION: Biochemical response at 12 months from baseline was better in patients with a rtM204I mutation than rtM204V+ rtM204I/V mutations. In addition, early treatment failure was more common in patients with rtM204V+ rtM204I/V mutations than a rtM204I mutation.

Subjects with diarrhea-predominant IBS have increased rectal permeability responsive to tryptase.

BACKGROUND AND AIMS: Patients with diarrhea-predominant irritable bowel syndrome (IBS-D) appear to have increased intestinal permeability; it has been suggested that activation of protease-activated receptor-2 (PAR-2) receptors is responsible for this alteration. The aims of this study are to evaluate (1) if rectal (large bowel) permeability is increased in IBS-D and (2) if tryptase plays a critical role in the altered permeability. METHODS: Rectal biopsies from 20 patients with IBS-D and 30 subjects without the condition (normal controls) were assessed for macromolecular permeability using horseradish peroxidase in Ussing chambers in the basal state and after addition of drugs to the basolateral side. Reverse-transcription polymerase chain reaction (RT-PCR) was performed using colonic biopsy tissues from patients with IBS-D and normal subjects. RESULTS: When tryptase was added to the basolateral (not mucosal) side of normal rectal biopsy tissues, permeability appeared to be proportional to the increase in tryptase concentration (P < 0.05) and was abolished by the addition of tryptase inhibitor (100 µM nafamostat; 1.568 ± 0.874 ng/2 h/mm(2) to 0.766 ± 0.661 ng/2 h/mm(2), n = 14, respectively, P < 0.01). Intestinal permeability in patients with IBS-D was significantly increased compared with controls (0.848 ± 0.0.600 ng/2 h/mm(2), n = 21, P < 0.01). Nafamostat significantly reduced the enhanced permeability in IBS-D (0.934 ± 0.589 ng/2 h/mm(2) to 0.247 ± 0.263 ng/2 h/mm(2), n = 14, respectively, P < 0.05). Transcription levels of PAR2 measured by RT-PCR did not differ between IBS-D and normal subjects. CONCLUSION: Tryptase seems to play an important role in the control of human colonic mucosal permeability, and enhanced tryptase activity was responsible for the increased permeability of rectal mucosa in IBS patients.

Impact of type 2 diabetes on manifestations and treatment outcome of pulmonary tuberculosis.

Diabetes mellitus (DM) is a known risk factor for pulmonary tuberculosis (PTB). This study aimed to determine if type 2 DM alters manifestations and treatment outcome of PTB. Records of 217 consecutive culture-proven PTB patients were analysed retrospectively. The manifestations and treatment outcomes of 74 patients with type 2 DM (PTB-DM group) were compared to 143 patients without DM (PTB group). PTB-DM patients showed higher frequencies of fever, haemoptysis, positive acid-fast bacilli sputum smears, and consolidation, cavity, and lower lung field lesions on chest radiographs, and higher mortality rate. Furthermore, type 2 DM, age 65 years, and extensive radiographic disease were factors independently associated with an unfavorable outcome. This study confirmed that clinical manifestations and chest radiographs of PTB patients associated with type 2 DM significantly depart from the typical presentation. Type 2 DM seems to have a negative effect on treatment outcome of PTB.

The impact of age on the demographic, clinical, radiographic characteristics and treatment outcomes of pulmonary tuberculosis patients in Taiwan.

BACKGROUND: The characteristics of pulmonary tuberculosis (TB) in the elderly are different from young patients. This leads to delay in diagnosis and higher mortality from TB in the aged population. The aim of this study was to investigate the impact of age on the demographic, clinical, radiographic characteristics, and treatment outcomes of pulmonary TB patients in Taiwan. MATERIALS AND METHODS: We performed a retrospective analysis of the medical charts and chest radiographs of 83 elderly (> or =60 years old) and 74 young (< 60 years old) culture-proven pulmonary TB patients from 1 August 2003 to 31 July 2006. RESULTS: Elderly patients showed lower frequencies of infectious TB contact history, alcoholism, cavity, and positive acid-fast bacilli sputum smears. In contrast, the elderly population had higher frequencies of chronic obstructive lung disease, heart failure, stroke, dyspnea, lower lung field involvement, pleural effusion and mortality. There were no differences between these two groups regarding sex, initial body weight, previous TB disease, hospital admission, diabetes mellitus, end-stage renal disease, neoplasm, liver cirrhosis, upper lung field involvement, cure, and treatment completion. Furthermore, age of 60 and older, lower initial body weight less than 50 kg, coexisting medical diseases, and extensive radiographic disease were factors independently associated with unfavorable outcomes. CONCLUSIONS: Elderly patients with pulmonary TB are more likely to present with negative sputum smears, cavity-negative lesions, lower lung field involvement and pleural effusion on chest radiographs. The prognosis is poor for the elderly pulmonary TB patients with lower body weight, coexisting medical diseases, and extensive radiographic disease.

Analysis of rectal dynamic and static compliances in patients with irritable bowel syndrome.

AIMS: Our aim was to investigate whether the dynamic and static compliances differ between patients with irritable bowel syndrome (IBS) and normal subjects. MATERIALS AND METHODS: Fifty-five IBS patients (age range 20-65 years, mean age 39.0 years, 28 women and 27 men; 36 diarrhea-predominant IBS (IBS-D) patients and 19 constipation-predominant IBS (IBS-C) patients) with symptoms that fulfilled the Rome-II criteria and 21 healthy controls (age range 25-58 years, mean age 37.8 years; 11 women and ten men) were recruited. The anorectal functions, including dynamic compliance, were evaluated via barostat tests. A power exponential model was used for the evaluation of static compliance. RESULTS: There was no significant difference in dynamic compliance between the normal subjects and the IBS patients (10.3+/-3.1 and 8.9+/-2.9 mmHg, respectively, P>0.05). However, even though no significant difference was detected in the overall shape of the curve (beta; P>0.05), there were significant differences in the kappa and P (half) between the normal subjects and the IBS patients (P<0.05), respectively. When we compared the dynamic and static compliances between the IBS-C and IBS-D patients, there were no significant differences found (P>0.05). CONCLUSIONS: An exponential model provided good fit to the actual data, and there were significant differences in static compliance between the normal subjects and the IBS patients. This result can reveal the altered biomechanical properties of the gut wall in IBS patients.

Factors affecting abdominal pain during colonoscopy.

OBJECTIVE: The actual degree of pain or discomfort experienced during colonoscopy varies between patients. This prospective study was conducted to determine what variables, apart from the endoscopist's skill, are associated with a patient's discomfort during this procedure. DESIGN/METHODS: From December 2003 to September 2004, 646 colonoscopy examinations performed by three experienced endoscopists were analysed. Midazolam and meperidine were administered intravenously 10 min before the procedure. The degree of patient discomfort was assessed by asking more than five times during the procedure and by using a visual analogue pain scale (0-10) examined up to 7 days after the procedure. Patients were divided into sub-groups as follows: (1) comfortable group (n=304), no complaint during the procedure; and (2) uncomfortable group (n=342), more than one complaint during the procedure. RESULTS: The correlation between the degree of patient discomfort and the results of the visual analogue pain scale was statistically significant (r2=0.118, P<0.01). Chi-squared analyses demonstrated that female gender, younger age (480 s), technically difficult insertion, and lower body mass index (BMI) are factors associated with uncomfortable procedure. Multivariate analysis demonstrated that younger age, female gender, lower BMI, difficulty of examination, and previous gynaeco-pelvic surgery in female gender are independent factors associated with discomfort during colonoscopy. CONCLUSIONS: An uncomfortable colonoscopic procedure will be expected in younger, female patients with a history of gynaeco-pelvic surgery.

Prevalence and risk factors of non-alcoholic fatty liver disease among Korean adults.

BACKGROUND AND AIM: Differences in the prevalence of non-alcoholic fatty liver disease (NAFLD) between Eastern and Western populations are primarily attributable to differences in definitions and biased population selection. Thus, the aim of the present study was to accurately determine the actual prevalence of NAFLD by sonography and to characterize the risk factors for NAFLD. METHODS: The present cross-sectional study was performed with data obtained from 6,648 subjects, all of whom were older than 20 years of age (3,530 men and 3,118 women). The term 'non-drinker' was applied to men who consumed less than 30 g alcohol/day and to women who consumed less than 20 g alcohol/day. Non-alcoholic fatty liver disease was defined as a sonographically detected fatty liver in the absence of viral hepatitis in a non-drinker. RESULTS: Of the 1,613 subjects who were diagnosed with sonographic fatty liver, 1,240 were non-drinkers and had no viral hepatitis. Overall, the unadjusted and age-adjusted prevalences of NAFLD were 18.7% (23% in men, 13.7% in women) and 16.1% (21.6% in men, 11.2% in women), respectively. Multivariate analysis revealed that several risk factors were profoundly associated with the prevalence of NAFLD, including obesity, insulin resistance, hyperlipidemia and hyperglycemia in both genders, as well as age, menopausal status and estrogen medication in women only. CONCLUSIONS: These results demonstrate that the prevalence of NAFLD in Korean adults, according to sonographic surveys, is comparable to that seen in more developed countries. From the perspective of increasing obesity, the high prevalence rates noted in the study may herald an increased burden of chronic liver disease in the Korean population.

Deep vein thrombosis following hip fracture and prevalence of hyperhomocysteinaemia in the elderly.

INTRODUCTION: The prevalence of deep vein thrombosis (DVT) in the West is reported to be as high as 50% after hip surgery. A study performed 14 years ago showed the incidence in Singapore to be <10%. Lately, some case-control and cross-sectional studies have suggested hyperhomocysteinaemia as an independent risk factor for DVT. This study investigates the local incidence of DVT and plasma hyperhomocysteinaemia in elderly patients presenting with proximal hip fracture. MATERIALS AND METHODS: We recruited 104 consecutive patients from April 2001 to November 2001 who satisfy certain criteria. Firstly, patients of both genders who were >55 years old with radiological diagnosis of neck of femur fracture, intertrochanteric or subtrochanteric fracture. Secondly, these patients must not have any haemorrhagic or thrombogenic disease. Thirdly, patients were not given folate and B complex pre- or postoperation. Duplex ultrasound was then done for these patients on the 5th to 7th postoperative day. RESULTS: The incidence of DVT above the trifurcation was 7.7%, no incidence of pulmonary embolism (PE) was detected. The incidence of hyperhomocysteinaemia was 52.3%. CONCLUSIONS: The incidence of DVT in the local population after proximal hip fracture is much lower than in the West. The use of DVT prophylaxis in Asians should be selective to avoid incurring extra cost and its associated morbidity. Case-control studies and cross-sectional studies clearly indicate that hyperhomocysteinaemia is an independent risk factor for venous thrombosis. Given the high incidence of hyperhomocysteinaemia in our elderly with hip fracture, the prophylactic correction of hyperhomocysteinaemia with folate and vitamin B supplements is justified.

Tryptase inhibition blocks airway inflammation in a mouse asthma model.

Release of human lung mast cell tryptase may be important in the pathophysiology of asthma. We examined the effect of the reversible, nonelectrophilic tryptase inhibitor MOL 6131 on airway inflammation and hyper-reactivity in a murine model of asthma. MOL 6131 is a potent selective nonpeptide inhibitor of human lung mast cell tryptase based upon a beta-strand template (K(i) = 45 nM) that does not inhibit trypsin (K(i) = 1,061 nM), thrombin (K(i) = 23, 640 nM), or other serine proteases. BALB/c mice after i.p. OVA sensitization (day 0) were challenged intratracheally with OVA on days 8, 15, 18, and 21. MOL 6131, administered days 18-21, blocked the airway inflammatory response to OVA assessed 24 h after the last OVA challenge on day 22; intranasal delivery (10 mg/kg) had a greater anti-inflammatory effect than oral delivery (10 or 25 mg/kg) of MOL 6131. MOL 6131 reduced total cells and eosinophils in bronchoalveolar lavage fluid, airway tissue eosinophilia, goblet cell hyperplasia, mucus secretion, and peribronchial edema and also inhibited the release of IL-4 and IL-13 in bronchoalveolar lavage fluid. However, tryptase inhibition did not alter airway hyper-reactivity to methacholine in vivo. These results support tryptase as a therapeutic target in asthma and indicate that selective tryptase inhibitors can reduce allergic airway inflammation.

The reductive effects of noncontingent reinforcement fixed-time versus variable-time schedules.

The effects of fixed-time (FT) and variable-time (VT) schedules on responding were evaluated with 2 adults with mental retardation. Multielement and reversal designs were used to compare the effects of FT and VT schedules in reducing responses previously maintained on variable-ratio reinforcement schedules. The schedules were equally effective in reducing the target behavior.

Regulation of chemokine mRNA expression in a rat model of vanadium-induced pulmonary inflammation.

Environmental and occupational exposure to vanadium dusts results in toxic effects mainly confined to the respiratory system. Using a rat model of acute lung inflammation induced by intratracheal instillation of sodium metavanadate (NaVO3) at the dose of 200 microg V/kg, we investigated the relationship between the cytologic characterization of pulmonary inflammation and the expression of chemokine mRNA. Significant polymorphonuclear leukocyte (PMN) influx (P < 0.01) into the lung was noted 4 h after NaVO3 instillation, whereas alveolar macrophages (AMs) in bronchoalveolar lavage (BAL) cells appeared to decrease significantly. In contrast, neither PMNs nor AMs changed substantially 1 h after NaVO3 instillation. By Northern analysis, macrophage inflammatory protein (MIP)-2 mRNA in BAL cells increased markedly 1 h after NaVO3 instillation and reduced a little bit at 4 h, whereas MIP-1alpha mRNA in BAL cells was expressed relatively high 1 h after NaVO3 instillation, although a basal expression was detected in control group, and returned rapidly nearly to control level at 4 h. Since MIP-2 is a potent PMN chemoattractant and MIP-1alpha is a potent macrophage/monocyte chemoattractant has been well known. The facts that PMN influx was preceded by increased MIP-2 mRNA expression, suggesting that MIP-2 is involved in the development of NaVO3-induced pulmonary inflammation, whereas increased MIP-1alpha mRNA expression was followed by decreased AMs in BAL cells, suggesting AMs might be activated by MIP-1alpha, adherent to the lining surface of the airways and then resistant to be washed out. To delineate the mechanisms of transcriptional activation, we recently cloned the 5'-flanking region of the MIP-2 gene. The promotor region contains consensus binding sites for transcription factor nuclear factor kappaB (NF-kappaB) and activator protein-1 (AP-1). Using electrophoretic mobility shift assay, increased nuclear NF-kappaB, not AP-1, binding activity was detected 1 h after NaVO3 instillation, which correlated with the induction of MIP-2 mRNA. p65 (Rel A) and p50 protein appears to be involved in MIP-2 NF-kappaB binding. Taken together, our studies suggest that MIP-2 is an important mediator of NaVO3-induced pulmonary inflammation in the rat model. In addition, elevated MIP-2 mRNA levels are accompanied by increased NF-kappaB binding activity in BAL cells, suggesting possible MIP-2 transcriptional regulation through NF-kappaB.

Expression and regulation of macrophage inflammatory protein-2 gene by vanadium in mouse macrophages.

Environmental and occupational exposure to vanadium (V) dusts results in inflammation mainly confined to the respiratory tract. Macrophages apparently play an important role in mediating the inflammation via the production of many chemokines. In the current study, we investigated whether vanadium can regulate the gene expression of a CXC chemokine macrophage inflammatory protein-2 (MIP-2), and to determine the molecular mechanisms controlling MIP-2 gene expression. A mouse macrophage cell line RAW 264.7 was treated with sodium metavanadate (NaVO3) at the dose of 0.5, 5, or 10 microg/mi V. Northern blot analysis showed that induction of MIP-2 mRNA expression was in a dose-dependent manner. To define the time course of the inflammatory response, RAW 264.7 cells were exposed to 5 microg/ml V, MIP-2 mRNA in macrophages increased markedly as early as 1 h after treatment, maximally induced at 4 h and reduced to 2-fold above control levels by 6 and 8 h. The protein levels of MIP-2 in conditioned media, measured by enzyme-linked immunosorbent assay (ELISA), was well correlated with the levels of MIP-2 mRNA following all of the treatments in the study. In addition, the increase in MIP-2 mRNA expression by vanadium was attenuated by co-treatment with the antioxidant N-acetylcysteine (NAC), at the doses of 10 and 20 mM, suggesting that the induction of MIP-2 mRNA is mediated via the generation of reactive oxygen species (ROS). To further investigate transcriptional regulation of the MIP-2 gene expression by vanadium, we performed RNA decay assay by measuring the half-life of MIP-2 mRNA. Co-treatment of macrophages with the transcriptional inhibitor actinomycin D at 5 microg/ml following exposure to 5 microg/ml V for 4 h revealed complete stabilization of vanadium-induced MIP-2 mRNA and no sign of mRNA degradation, at least, for 6 h, in comparison to the half-life of MIP-2 mRNA was approximately 2.5 h by bacterial lipopolysaccharide (LPS) treatment, supporting post-transcriptional stabilization as the predominant role of MIP-2 gene expression. In conclusion, these observations demonstrate that in vitro vanadium can induce MIP-2 mRNA expression, mediating, at least in part, via the production of ROS. In addition, the increase in MIP-2 mRNA level involves, most likely, post-transcriptional control via increased mRNA stability.