Increased expression of the dopamine transporter leads to loss of dopamine neurons, oxidative stress and l-DOPA reversible motor deficits

The dopamine transporter is a key protein responsible for regulating dopamine homeostasis. Its function is to transport dopamine from the extracellular space into the presynaptic neuron. Studies have suggested that accumulation of dopamine in the cytosol can trigger oxidative stress and neurotoxicity. Previously, ectopic expression of the dopamine transporter was shown to cause damage in non-dopaminergic neurons due to their inability to handle cytosolic dopamine. However, it is unknown whether increasing dopamine transporter activity will be detrimental to dopamine neurons that are inherently capable of storing and degrading dopamine. To address this issue, we characterized transgenic mice that over-express the dopamine transporter selectively in dopamine neurons. We report that dopamine transporter over-expressing (DAT-tg) mice display spontaneous loss of midbrain dopamine neurons that is accompanied by increases in oxidative stress markers, 5-S-cysteinyl-dopamine and 5-S-cysteinyl-DOPAC. In addition, metabolite-to-dopamine ratios are increased and VMAT2 protein expression is decreased in the striatum of these animals. Furthermore, DAT-tg mice also show fine motor deficits on challenging beam traversal that are reversed with l-DOPA treatment. Collectively, our findings demonstrate that even in neurons that routinely handle dopamine, increased uptake of this neurotransmitter through the dopamine transporter results in oxidative damage, neuronal loss and l-DOPA reversible motor deficits. In addition, DAT over-expressing animals are highly sensitive to MPTP-induced neurotoxicity. The effects of increased dopamine uptake in these transgenic mice could shed light on the unique vulnerability of dopamine neurons in Parkinson's disease.

Phase I safety, pharmacokinetic, and pharmacodynamic study of SAR245408 (XL147), an oral pan-class I PI3K inhibitor, in patients with advanced solid tumors

PURPOSE

SAR245408 is a pan-class I phosphoinositide 3-kinase (PI3K) inhibitor. This phase I study determined the maximum tolerated dose (MTD) of two dosing schedules [first 21 days of a 28-day period (21/7) and continuous once-daily dosing (CDD)], pharmacokinetic and pharmacodynamic profiles, and preliminary efficacy.

EXPERIMENTAL DESIGN

Patients with refractory advanced solid malignancies were treated with SAR245408 using a 3 + 3 design. Pharmacokinetic parameters were determined after single and repeated doses. Pharmacodynamic effects were evaluated in plasma, hair sheath cells, and skin and tumor biopsies.

RESULTS

Sixty-nine patients were enrolled. The MTD of both schedules was 600 mg; dose-limiting toxicities were maculopapular rash and hypersensitivity reaction. The most frequent drug-related adverse events included dermatologic toxicities, diarrhea, nausea, and decreased appetite. Plasma pharmacokinetics showed a median time to maximum concentration of 8 to 22 hours, mean terminal elimination half-life of 70 to 88 hours, and 5- to 13-fold accumulation after daily dosing (first cycle). Steady-state concentration was reached between days 15 and 21, and exposure was dose-proportional with doses up to 400 mg. SAR245408 inhibited the PI3K pathway (∼40%-80% reduction in phosphorylation of AKT, PRAS40, 4EBP1, and S6 in tumor and surrogate tissues) and, unexpectedly, also inhibited the MEK/ERK pathway. A partial response was seen in one patient with advanced non-small cell lung cancer. Eight patients were progression-free at 6 months. Pharmacodynamic and clinical activity were observed irrespective of tumor PI3K pathway molecular alterations.

CONCLUSIONS

SAR245408 was tolerable at doses associated with PI3K pathway inhibition. The recommended phase II dose of the capsule formulation is 600 mg administered orally with CDD.

Mobilizing and evaluating anticancer T cells: pitfalls and solutions

Immunotherapy is a promising means to fight cancer, prompting a steady increase in clinical trials and correlative laboratory studies in this field. As antitumor T cells play central roles in immunity against malignant diseases, most immunotherapeutic protocols aim to induce and/or strengthen their function. Various treatment strategies have elicited encouraging clinical responses; however, major challenges have been uncovered that should be addressed in order to fully exploit the potential of immunotherapy. Here, we outline pitfalls for the mobilization of antitumor T cells and offer solutions to improve their therapeutic efficacy. We provide a critical perspective on the main methodologies used to characterize T-cell responses to cancer therapies, with a focus on discrepancies between T-cell attributes measured in vitro and protective responses in vivo. This review altogether provides recommendations to optimize the design of future clinical trials and highlights important considerations for the proficient analysis of clinical specimens available for research.

Tumoral lymphocytic infiltration and expression of the chemokine CXCL10 in breast cancers from the Ontario Familial Breast Cancer Registry

PURPOSE

Breast carcinomas, including basal and hereditary cases, often present with a prominent tumoral lymphocytic infiltrate. Chemokines could play a role in attracting these cells and contribute to tumor progression. We explored tumoral expression of CXCL10 and determined the relationship between CXCL10 and lymphocytic infiltrate in a cohort of breast cancers.

EXPERIMENTAL DESIGN

Using tissue microarrays of 364 breast tumors, we evaluated expression of CXCL10 and its receptor, CXCR3, in relation to histopathologic features, biomarkers, and lymphocyte markers. In addition, we overexpressed CXCL10 and CXCR3 in MCF7 breast cancer cells and monitored T-lymphocyte migration and invasion.

RESULTS

Forty-five percent of tumors expressed CXCL10, and a significant association was found with CXCR3 and lymphocytic infiltrate. Further characterization of the lymphocytic infiltrate revealed an association with CXCL10 expression for peritumoral CD4+ and CD8+ lymphocytes. CD8+ intratumoral lymphocytes, FOXP3+ regulatory T cells (Tregs), and T-BET+ T(H)1 cells were associated with BRCA1 and basal tumors. Conditioned media from MCF7 cells overexpressing both CXCL10 and CXCR3 increased T-lymphocyte migration and invasion.

CONCLUSIONS

Our findings suggest that CXCL10 may act in a paracrine manner, affecting the tumor microenvironment, and in an autocrine manner, acting on the tumor cells themselves and may play a role in tumor invasiveness and progression. The CXCL10-CXCR3 axis can serve as a potential target in BRCA1 and basal breast cancers, which present with a prominent lymphocytic infiltrate and a poor prognosis. Clin Cancer Res; 19(2); 336-46. ©2012 AACR.

Characteristics of child abuse homicides in the state of Kansas from 1994 to 2007

OBJECTIVE

This study described the epidemiology of child abuse homicides in the state of Kansas from 1994 to 2007. It focused on obtaining significant details on all recorded child abuse homicides in Kansas during this time frame to provide critical information that can be used for future preventive measures.

METHODS

A retrospective case review was conducted on data gathered by the Kansas State Child Death Review Board for all cases of "child abuse homicides" that occurred from 1994 to 2007.

RESULTS

A total of 170 child abuse homicide cases in Kansas between 1994 and 2007 were identified. The majority of these cases (63.5%) were considered fatal child physical abuse. There was a predominance of female victims (55.9%). The vast majority of victims were White (78.8%), followed by Black (17.1%). One to 2-year-olds accounted for the largest age group of children who were victimized (33.5%). For cases with known prenatal care status, 74% of mothers received adequate prenatal care. The largest percentage of victims was children of single mothers (40.6%), with no prior history of child abuse (60%). The majority of deaths occurred in the victim's residence (81.8%). The greatest number of deaths occurred secondary to abusive head trauma (42.9%), followed by asphyxia (21.8%). When a trigger was known, 44.2% involved inconsolable crying. The most common perpetrator was the victim's biological father (26.6%), followed by the victim's biological mother (24.9%), then the victim's mother's male paramour (19.8%).

CONCLUSIONS

Familiarity with characteristics involved in child abuse homicide allows for opportunities to enlist important preventive measures. Most child abuse homicides occurred at the hands of the victim's biological parents and in the victim's own residence. Prevention should be focused on parent education and coping mechanisms for the frustrating features of crying in normal infants that lead to shaking or abuse.

Expansion and characterization of human melanoma tumor-infiltrating lymphocytes (TILs)

Background

Various immunotherapeutic strategies for cancer are aimed at augmenting the T cell response against tumor cells. Adoptive cell therapy (ACT), where T cells are manipulated ex vivo and subsequently re-infused in an autologous manner, has been performed using T cells from various sources. Some of the highest clinical response rates for metastatic melanoma have been reported in trials using tumor-infiltrating lymphocytes (TILs). These protocols still have room for improvement and furthermore are currently only performed at a limited number of institutions. The goal of this work was to develop TILs as a therapeutic product at our institution.

Principal Findings

TILs from 40 melanoma tissue specimens were expanded and characterized. Under optimized culture conditions, 72% of specimens yielded rapidly proliferating TILs as defined as at least one culture reaching ≥3×10⁷ TILs within 4 weeks. Flow cytometric analyses showed that cultures were predominantly CD3+ T cells, with highly variable CD4+:CD8+ T cell ratios. In total, 148 independent bulk TIL cultures were assayed for tumor reactivity. Thirty-four percent (50/148) exhibited tumor reactivity based on IFN-γ production and/or cytotoxic activity. Thirteen percent (19/148) showed specific cytotoxic activity but not IFN-γ production and only 1% (2/148) showed specific IFN-γ production but not cytotoxic activity. Further expansion of TILs using a 14-day “rapid expansion protocol” (REP) is required to induce a 500- to 2000-fold expansion of TILs in order to generate sufficient numbers of cells for current ACT protocols. Thirty-eight consecutive test REPs were performed with an average 1865-fold expansion (+/− 1034-fold) after 14 days.

Conclusions

TILs generally expanded efficiently and tumor reactivity could be detected in vitro. These preclinical data from melanoma TILs lay the groundwork for clinical trials of ACT.

Obstructive sleep apnoea and perioperative complications in bariatric patients

BACKGROUND

The objective of this study was to determine the relationship between perioperative complications and the severity of obstructive sleep apnoea (OSA) in patients undergoing bariatric surgery who had undergone preoperative polysomnography (PSG).

METHODS

The records of 797 patients, age >18 yr, who underwent bariatric operations (442 open and 355 laparoscopic procedures) at Mayo Clinic and were assessed before operation by PSG, were reviewed retrospectively. OSA was quantified using the apnoea-hypopnoea index (AHI) as none (≤ 4), mild (5-15), moderate (16-30), and severe (≥ 31). Pulmonary, surgical, and 'other' complications within the first 30 postoperative days were analysed according to OSA severity. Logistic regression was used to assess the multivariable association of OSA, age, sex, BMI, and surgical approach with postoperative complications.

RESULTS

Most patients with OSA (93%) received perioperative positive airway pressure therapy, and all patients were closely monitored after operation with pulse oximetry on either regular nursing floors or in intensive or intermediate care units. At least one postoperative complication occurred in 259 patients (33%). In a multivariable model, the overall complication rate was increased with open procedures compared with laparoscopic. In addition, increased BMI and age were associated with increased likelihood of pulmonary and other complications. Complication rates were not associated with OSA severity.

CONCLUSIONS

In obese patients evaluated before operation by PSG before bariatric surgery and managed accordingly, the severity of OSA, as assessed by the AHI, was not associated with the rate of perioperative complications. These results cannot determine whether unrecognized and untreated OSA increases risk.

Maternal undernutrition alters fat cell size distribution, but not lipogenic gene expression, in the visceral fat of the late gestation guinea pig fetus

This study investigated the development of adipose tissue in the guinea pig and the impact of maternal undernutrition on the structural and functional characteristics of perirenal adipose tissue in the dam and fetus. Date-mated guinea pigs were provided with either ad libitum feed (Control, C) or 85% of food intake per body weight of the Controls (Undernutrition, UN). Maternal (C, n = 6; UN, n = 7) perirenal adipose tissue (PAT) was collected at 60 d gestation and fetal PAT was collected at 50 d (C, n = 4) and 60 d (C, n = 8 and UN, n = 7) gestation (term, 69 d). The expression of stearoyl-CoA desaturase (SCD-1), fatty acid synthase (FAS), lipoprotein lipase (LPL), leptin and glycerol 3 phosphate dehydrogenase (G3PDH) mRNA and glucose transporters 1 and 4 (GLUT1 and GLUT4) was determined by Real Time PCR. There was no effect of maternal UN on total or relative PAT mass in the pregnant dam. There was an increase in G3PDH, but not LPL, leptin, FAS or GLUT4 mRNA expression, in UN dams compared to Controls (P < 0.05). In the fetal guinea pig there was no effect of maternal UN on total or relative PAT mass, however, the UN fetuses had a higher percentage of larger lipid locules in their PAT compared to Controls (P < 0.05). The expression of FAS, LPL, SCD-1, leptin, G3PDH and GLUT4 mRNA in PAT was not different between the Control and UN fetuses. These results support previous studies which have demonstrated that maternal undernutrition is associated with an increased accumulation of visceral adipose tissue in utero, and extend them by showing that maternal undernutrition results in early changes in the size distribution of lipid locules in visceral fat depots that precede changes in lipogenic gene expression.

Helicobacter pylori dupA gene is not associated with clinical outcomes in the Japanese population

The dupA gene of Helicobacter pylori was suggested to be a risk factor for duodenal ulcer but protective against gastric cancer. The present study aimed to re-examine the role of dupA in H. pylori-infected Japanese patients. We found that dupA status was not associated with any gastroduodenal disease, histological score of chronic gastritis or with the extent of interleukin-8 production from gastric cell lines. These results indicate that dupA is unlikely to be a virulence factor of H. pylori in the Japanese population.

Helicobacter pylori dupA gene is not associated with clinical outcomes in the Japanese population

The dupA gene of Helicobacter pylori was suggested to be a risk factor for duodenal ulcer but protective against gastric cancer. The present study aimed to re-examine the role of dupA in H. pylori-infected Japanese patients. We found that dupA status was not associated with any gastroduodenal disease, histological score of chronic gastritis or with the extent of interleukin-8 production from gastric cell lines. These results indicate that dupA is unlikely to be a virulence factor of H. pylori in the Japanese population.

Genome-wide analysis of DNA copy number alterations and gene expression in gastric cancer

Genomic copy number aberrations (CNAs) are believed to play a major role in the development and progression of human cancers. Although many CNAs have been reported in gastric cancer, their genome-wide transcriptional consequences are poorly understood. In this study, to reveal the impact of CNAs on genome-wide expression in gastric cancer, we analysed 30 cases of gastric cancers for their CNAs by array comparative genomic hybridization (array CGH) and 24 of these 30 cases for their expression profiles by oligonucleotide-expression microarray. We found that with the application of laser microdissection, most CNAs were detected at higher frequency than in previous studies. Notably, gain at 20q13 was detected in almost all cases (97%), suggesting that this may play an important role in the pathogenesis of gastric cancer. By comparing the array CGH data with expression profiles of the same samples, we showed that both genomic amplification and deletion strongly influence the expression of genes in altered genomic regions. Furthermore, we identified 125 candidate genes, consisting of 114 up-regulated genes located in recurrent regions (>10%) of amplification and 11 down-regulated genes located in recurrent regions of deletion. Up-regulation of several candidate genes, such as CDC6, SEC61G, ANP32E, BYSL and FDFT1, was confirmed by immunohistochemistry. Interestingly, some candidate genes were localized at genomic loci adjacent to well-known genes such as EGFR, ERBB2 and SMAD4, and concordantly deregulated by genomic alterations. Based on these results, we propose that our list of candidate genes may contain novel genes involved in the pathogenesis of advanced gastric cancer.

Genome-wide microRNA expression profiling in renal cell carcinoma: significant down-regulation of miR-141 and miR-200c

We investigated expression profiles of microRNA (miRNA) in renal cell carcinoma [clear cell carcinomas (CCC) and chromophobe renal cell carcinomas (ChCC)] and in normal kidneys by using a miRNA microarray platform which covers a total of 470 human miRNAs (Sanger miRBase release 9.1). Unsupervised hierarchical cluster analysis revealed that CCC and ChCC were separable and that no subgroups were identified in CCCs. We found that 43 miRNAs were differentially expressed between CCC and normal kidney, of which 37 were significantly down-regulated in CCC and the other 6 were up-regulated. We also found that 57 miRNAs were differentially expressed between ChCC and normal kidney, of which 51 were significantly down-regulated in ChCC and the other 6 were up-regulated. Together, these observations indicate that expression of miRNAs tends to be down-regulated in both CCC and ChCC compared with normal kidney. We observed that miR-141 and miR-200c were the most significantly down-regulated miRNAs in CCCs. Indeed, in all cases of CCC analysed, both miR-141 and miR-200c were down-regulated in comparison with normal kidney. Microarray data and quantitative RT-PCR showed that these two miRNAs were expressed concordantly. TargetScan algorithm revealed that ZFHX1B mRNA is a hypothetical target of both miR-141 and -200c. We established by quantitative RT-PCR that, in CCCs in which miR-141 and miR-200c were down-regulated, ZFHX1B, a transcriptional repressor for CDH1/E-cadherin, tended to be up-regulated. Furthermore, we found that overexpression of miR-141 and miR-200c caused down-regulation of ZFHX1B and up-regulation of E-cadherin in two renal carcinoma cell lines, ACHN and 786-O. On the basis of these findings, we suggest that down-regulation of miR-141 and miR-200c in CCCs might be involved in suppression of CDH1/E-cadherin transcription via up-regulation of ZFHX1B.

A meta-analysis of the placebo response in complementary and alternative medicine trials of irritable bowel syndrome

Among patients with irritable bowel syndrome (IBS) enrolled in clinical trials of conventional medical therapy, the placebo response rate is high. IBS patients also frequently use complementary and alternative medicine (CAM), which may act through an 'enhanced placebo effect'. The purpose of this study was to estimate the magnitude of the placebo response rate in CAM trials for IBS and to identify factors that influence this response. We performed a systematic review and meta-analysis of randomized, placebo-controlled clinical trials of CAM therapies for IBS identified from MEDLINE/EMBASE/PsychLIT databases from 1970 to 2006. Placebo and active treatment response rates for global symptom improvement were assessed. Nineteen studies met the inclusion criteria. The pooled estimate of the placebo response rate was 42.6% (95% confidence interval, 38.0-46.5%). Significant heterogeneity existed across trials (range 15.0-72.2%, P < 0.00001). Higher placebo response rates correlated with a longer duration of treatment (r = 0.455, P = 0.05) and a greater number of office visits (r = 0.633, P = 0.03). Among IBS patients in CAM trials, the placebo response rate is high. That this rate is similar in magnitude to that seen in conventional medicine trials suggests that the placebo response is independent of the type of therapy used and that it is not particularly 'enhanced' in CAM trials.

A meta-analysis of the placebo response in complementary and alternative medicine trials of irritable bowel syndrome

Among patients with irritable bowel syndrome (IBS) enrolled in clinical trials of conventional medical therapy, the placebo response rate is high. IBS patients also frequently use complementary and alternative medicine (CAM), which may act through an 'enhanced placebo effect'. The purpose of this study was to estimate the magnitude of the placebo response rate in CAM trials for IBS and to identify factors that influence this response. We performed a systematic review and meta-analysis of randomized, placebo-controlled clinical trials of CAM therapies for IBS identified from MEDLINE/EMBASE/PsychLIT databases from 1970 to 2006. Placebo and active treatment response rates for global symptom improvement were assessed. Nineteen studies met the inclusion criteria. The pooled estimate of the placebo response rate was 42.6% (95% confidence interval, 38.0-46.5%). Significant heterogeneity existed across trials (range 15.0-72.2%, P < 0.00001). Higher placebo response rates correlated with a longer duration of treatment (r = 0.455, P = 0.05) and a greater number of office visits (r = 0.633, P = 0.03). Among IBS patients in CAM trials, the placebo response rate is high. That this rate is similar in magnitude to that seen in conventional medicine trials suggests that the placebo response is independent of the type of therapy used and that it is not particularly 'enhanced' in CAM trials.

Where FoxP3-dependent regulatory T cells impinge on the development of inflammatory arthritis

OBJECTIVE

Regulatory T cells play a suppressive role in many autoimmune diseases and can potentially affect various steps in the progression of disease. The purpose of this study was to analyze the role of Treg cells in the control of arthritis development.

METHODS

Using crosses and cell transfers, we tested the effect of the scurfy loss-of-function mutation of the Foxp3 gene in the K/BxN mouse model. In this model, arthritis develops as the result of the production of high levels of pathogenic autoantibodies.

RESULTS

The absence of Treg cells in K/BxN mice led to faster and more aggressive arthritis. Strikingly, disease also spread to joints not normally affected in this model. The absence of Treg cells resulted in an acceleration of the immunologic phase of disease, with significantly earlier autoantibody production. However, the broadened spectrum of affected joints in Foxp3-mutant mice was not due to the earlier appearance of autoantibodies and could not be reproduced by increasing the anti-glucose-6-phosphate isomerase antibody load, which demonstrates an impact of Treg cells on effector phase manifestations. In addition, FoxP3+,CD25+ Treg cells accumulated in inflamed joints, even in nontransgenic animals. This preferential localization mimics that in human arthritides and indicates a preferential homing/retention of Treg cells to sites of inflammation.

CONCLUSION

These results indicate that Treg cells play a role in antibody-mediated arthritis at several levels. Treg cells are involved in constraining the immune phase of disease, as well as limiting the articular damage provoked by the pathogenic autoantibodies in terms of severity and of the range of affected joints, which may contribute to the limited distal predominance of many arthritides.

Association between HLA-DQB1 and cervical dysplasia in Vietnamese women

Host genetic background seems to play a key role in cervical carcinogenesis as only a small subset of women infected with high-risk human papillomaviruses (HPVs) develop cervical cancer. The rate of cervical cancer in Vietnamese women is notably high. To explore the association of human leukocyte antigen (HLA)-DQB1 alleles, HPV infection, and cervical dysplasia in this population, cervical smears were obtained from 101 women attending the obstetrics and gynecology clinic of Da Nang General Hospital in Vietnam. Besides the Papanicolaou test, HPV and HLA-DQB1 genotyping were performed using cervical smear DNA. Additionally, a subset of 30 blood samples was used as the gold standard for HLA genotyping. HLA-DQB1 alleles showed no association with HPV infection status. However, a positive association with cervical dysplasia was found for HLA-DQB1*0302 (P= 0.0229, relative risk (RR) = 4.737) and HLA-DQB1*0601 (P= 0.0370, RR = 4.038), whereas HLA-DQB1*0301 (P= 0.0152, RR = 0.221) was found negatively associated. The low diversity of HLA-DQB1 alleles, wide spectrum of HPV genotypes, and high prevalence of HPV 16 and HPV 18 observed in the study population suggest a permissive/susceptible genetic background that deserves further research. Total concordance of HLA-DQB1 genotyping results between blood and cervical cells confirms the potential value of cervical smears as an effective tool for the development of cervical cancer biomarkers.

Capsaicin cough sensitivity in bronchiectasis

BACKGROUND

Bronchiectasis is a suppurative airway disease characterised by persistent cough and sputum production associated with bronchial dilatation. A study was undertaken to determine whether cough sensitivity is increased in bronchiectatic patients.

METHODS

Twenty two patients with bronchiectasis and 20 healthy non-smoking controls matched for age and sex were recruited into the study. Quality of life (Leicester Cough Questionnaire score), total cough symptom score, and extent of bronchiectasis on HRCT scans were recorded. Cough sensitivity was assessed using incremental inhalation of capsaicin concentrations; the concentration at which 5 or more coughs occurred (C5) was recorded.

RESULTS

Patients with bronchiectasis had increased sensitivity to capsaicin compared with controls (mean (SE) log10 C5 1.22 (0.20) v 1.89 (0.21); p<0.03). Capsaicin sensitivity correlated positively with the Leicester Cough Questionnaire score (r = 0.64; p = 0.005) and inversely with the total cough symptom score (r = -0.58; p = 0.004), but not with the extent of the disease. It also correlated with forced expiratory volume in 1 second (FEV1) in litres (r = 0.58; p = 0.005) but not with FEV1 % predicted. Capsaicin sensitivity was not related to the presence of infected sputum or to corticosteroid or bronchodilator use.

CONCLUSIONS

: Patients with bronchiectasis have a sensitive cough reflex which reflects the severity of cough symptoms. A measure of cough severity could be part of health assessment for patients with bronchiectasis.

Interleukin-4 can be a key positive regulator of inflammatory arthritis

OBJECTIVE

Development of arthritis in the K/BxN mouse model depends on the induction of high titers of antibodies against the enzyme glucose-6-phosphate isomerase (GPI), promoted by CD4(+) T cells expressing a GPI-specific transgenic T cell receptor (TCR). This study was undertaken to determine whether this strong autoantibody response depends on T cell differentiation to the Th1 or Th2 phenotype.

METHODS

The roles of Th cell-biasing cytokines were investigated by introducing the interleukin-4 (IL-4) and IL-12-specific subunit p35 (IL-12p35)-knockout mutations into the K/BxN model and evaluating the impact of these deficiencies on disease. The IL-4-expressing cell types in K/BxN mice were revealed by crossing in a knockin alteration, which resulted in green fluorescent protein expression controlled by endogenous IL-4 gene-regulatory elements. Transfer experiments permitted the identification of the IL-4-producing cell type required for arthritis, and quantitative reverse transcriptase-polymerase chain reaction allowed for determination of the cytokine profile of K/BxN T cells.

RESULTS

While IL-12p35 appeared dispensable for the development of arthritis, IL-4 was crucial for full development of disease. The GPI-reactive TCR of standard K/BxN mice induced the transcriptional activation of the IL-4 locus in CD4(+) T cells and eosinophils, and CD4(+) T cells were the obligatory source of IL-4 for disease. However, the cytokine profile of K/BxN T cells revealed that K/BxN arthritis is not a "pure" Th2 disease.

CONCLUSION

The K/BxN model, although not a classic Th2 disease, depends critically on IL-4. The potential of IL-4 to promote inflammatory arthritis should be considered when proposing therapies for rheumatoid arthritis aimed at biasing T cells toward IL-4 production.

Prevalence of Antimicrobial Resistance Genes inListeria monocytogenesIsolated from Dairy Farms

Antimicrobial resistance of Listeria monocytogenes (n = 38) isolated from the four dairy farms to 15 antimicrobial agents was evaluated. All 38 L. monocytogenes isolates from the four farms evaluated were resistant to more than one antimicrobial in different combinations. All L. monocytogenes isolates evaluated were resistant to cephalosporin C (minimum inhibitory concentration [MIC] > or = 512 microg/mL), streptomycin (MIC > or = 32) and trimethoprim (MIC > or = 512). Most L. monocytogenes isolates were resistant to ampicillin (92%, MIC > or = 2), rifampicin (84%, MIC > or = 4), rifamycin (84%, MIC > or = 4), and florfenicol (66%, MIC > or = 32) and some were resistant to tetracycline (45%, MIC > or = 16), penicillin G (40%, MIC > or = 2) and chloramphenicol (32%, MIC > or = 32). All L. monocytogenes isolates were susceptible to amoxicillin, erythromycin, gentamicin, kanamycin and vancomycin. Susceptibility of L. monocytogenes to the antimicrobials evaluated was quite consistent among the dairy farms evaluated. However, some variability in antimicrobial susceptibility among dairy farms was noted. Nineteen of 38 L. monocytogenes isolates contained more than one antimicrobial resistance gene sequence. A high frequency of floR (66%) was found in L. monocytogenes followed by penA (37%), strA (34%), tetA (32%), and sulI (16%). Other tetracycline resistance genes (tetB, tetC, tetD, tetE, and tetG) and other antimicrobial resistance genes (cmlA, strB, aadA, sulI, vanA, vanB, ampC, ermB, ereA, and ereB) were not found in any of the L. monocytogenes isolates from the four dairy farms. Results of the present study demonstrated that L. monocytogenes isolated from the dairy farm environment were resistant to many antimicrobials and contained one or more antimicrobial resistance genes.