Mutations in the ligand-binding and pore domains control exit of glutamate receptors from the endoplasmic reticulum in C. elegans

The abundance of ion channels and neurotransmitter receptors in the plasma membrane is limited by the efficiency of protein folding and subunit assembly in the endoplasmic reticulum (ER). The ER has a quality-control system for monitoring nascent proteins, which prevents incompletely folded and assembled proteins from being transported from the ER. Chaperone proteins identify unfolded and misassembled proteins in the ER via retention motifs that are normally buried at intersubunit contacts or via carbohydrate residues that are attached to misfolded domains. Here, we examined the trafficking of a C. elegans non-NMDA glutamate receptor (GLR-1). We show that mutations in the pore domain (predicted to block ion permeation) and mutations in the ligand-binding domain (predicted to block glutamate binding) both caused a dramatic reduction in the synaptic abundance of GLR-1 and increased retention of GLR-1 in the ER. These results suggest that the structural integrity of the ligand-binding site and the pore domain of GLR-1 are monitored in the ER during the process of quality control.     

The health politics of asthma: environmental justice and collective illness experience in the United States

While public health, medical, government, and community actors agree that there is a serious asthma epidemic, there is significant disagreement over the role of outdoor environmental factors in causing or triggering asthma. The outcome of these disputes is important because it substantially influences the focus of public health prevention and government regulation. Minority communities in the United States have higher morbidity rates than white communities and, as a result, are more readily affected by debates over environmental factors and subsequent public health and government efforts. Therefore, asthma has figured prominently in community activists' agendas concerning health inequalities. We compare and contrast the efforts of two community environmental justice organizations that include asthma as part of their overall community organizing efforts. We explore obstacles and strategies common to both groups as well as key differences in their orientation vis-à-vis science. To do so, we first discuss the discovery, current research, community action, and resultant changes in the understanding of the disease, specifically within poor and minority communities. Then, to offer a context to examine our two examples of asthma activism, we explore the social discovery of asthma and its environmental correlates, along with the political and economic conflicts surrounding asthma research and regulation. Using examples from the two activist groups, we discuss common approaches to address asthma in poor and minority communities such as challenging "transit racism", employing an environmental justice perspective, and using education to empower community members. Finally, we explore how the issues raised in terms of asthma and the environment lead to a collective form of illness experience, in which people with asthma make direct links to the social determinants of their health.     

Genomic and proteomic profiling of responses to toxic metals in human lung cells

Examining global effects of toxic metals on gene expression can be useful for elucidating patterns of biological response, discovering underlying mechanisms of toxicity, and identifying candidate metal-specific genetic markers of exposure and response. Using a 1,200 gene nylon array, we examined changes in gene expression following low-dose, acute exposures of cadmium, chromium, arsenic, nickel, or mitomycin C (MMC) in BEAS-2B human bronchial epithelial cells. Total RNA was isolated from cells exposed to 3 M Cd(II) (as cadmium chloride), 10 M Cr(VI) (as sodium dichromate), 3 g/cm2 Ni(II) (as nickel subsulfide), 5 M or 50 M As(III) (as sodium arsenite), or 1 M MMC for 4 hr. Expression changes were verified at the protein level for several genes. Only a small subset of genes was differentially expressed in response to each agent: Cd, Cr, Ni, As (5 M), As (50 M), and MMC each differentially altered the expression of 25, 44, 31, 110, 65, and 16 individual genes, respectively. Few genes were commonly expressed among the various treatments. Only one gene was altered in response to all four metals (hsp90), and no gene overlapped among all five treatments. We also compared low-dose (5 M, noncytotoxic) and high-dose (50 M, cytotoxic) arsenic treatments, which surprisingly, affected expression of almost completely nonoverlapping subsets of genes, suggesting a threshold switch from a survival-based biological response at low doses to a death response at high doses.     

Alemtuzumab (Campath-1H) combined with tacrolimus in intestinal and multivisceral transplantation

BACKGROUND: We combined alemtuzumab (Campath-1H, Berlex Laboratories, Montville, NJ) and tacrolimus (Tac) immunosuppression for intestinal and multivisceral transplantation. MATERIALS AND METHODS: A total of 21 adult patients received 24 grafts: 14 intestinal, nine multivisceral, and one liver-intestinal graft. Alemtuzumab was administered perioperatively in four doses with low-dose Tac (levels 10-15 ng/dL) and no maintenance steroids. Tac was substituted with sirolimus in case of Tac-related complications. Suspected or mild rejections were treated with steroids. Moderate rejections were treated with steroids or OKT3. Severe rejections were treated with OKT3. RESULTS: Of the 16 patients that were followed up for an average of 9 months, 12 are alive with functioning grafts. Two patients experienced severe rejection, three experienced moderate rejection episodes, and seven experienced mild acute rejection episodes. Four patients never developed acute rejection. Infectious complications included a cytomegalovirus enteritis and four fungal infections (related to central venous access). CONCLUSIONS: The combination of alemtuzumab and Tac therapy without steroid use seems to efficiently prevent acute rejection in a significant number of patients without causing frequent opportunistic infections.     

T cells in myeloma

The current trend to develop immunotherapy strategies for patients with myeloma and other B cell malignancies has stimulated considerable interest in the functional state of the T cell population in these patients. Expanded clones of T cells exist in many patients with myeloma and their presence is associated with an improved survival. However, isolating T cells with tumour specificity has proven to be a difficult task and clinical immunization trials have so far failed to achieve a significant response. There is now evidence that tumour specific T cells are either tolerized or deleted following antigen presentation and that idiotype-derived, immunodominant tumour peptides may not exist in all patients. In order to develop more effective immunotherapy strategies for patients with myeloma, further studies are urgently required to identify the most appropriate tumour antigen, the nature of the interactions which take place during antigen presentation, and how to promote the cytotoxicity of autologous T cells.     

Regional delivery and selective expression of a high-activity yeast cytosine deaminase in an intrahepatic colon cancer model

A major potential limitation to the success of enzyme prodrug gene therapy is the toxicity that could result from gene expression in normal tissues. In this study, we investigated the use of an enhanced human carcinoembryonic antigen (CEA) promoter for yeast cytosine deaminase (yCD), which converts 5-fluorocytosine to 5-fluorouracil, to increase targeting while maintaining activity both in cell culture and in nude rats bearing intrahepatic xenografts. We found that an enhanced CEA-yCD adenoviral vector can achieve significantly greater yCD expression in CEA-expressing colon carcinoma cell lines (LoVo, HT29, and CaCo2) compared with a nonspecific Rous sarcoma virus-yCD virus. In contrast, infection with CEA-yCD led to lower or equivalent yCD expression in normal hepatocytes or fibroblasts compared with that produced by the RSV-yCD. Adenovirus administered in the portal vein or the hepatic artery of nude rats bearing intrahepatic LoVo colon carcinomas could mediate beta-galactosidase expression equally in liver and tumors under the control of cytomegalovirus, a nonspecific promoter. However, infusion of CEA-yCD virus markedly increased yCD expression in tumors over normal liver (>4-fold) measured both by levels of mRNA and yCD activity. Moreover, the efficiency of 5-fluorocytosine conversion into 5-fluorouracil in tumors was significantly higher than that in normal liver ( approximately 3-fold) in rats receiving portal venous viral infusion of CEA-yCD and subsequent 5FC treatment. Thus, an enhanced CEA promoter can preferentially stimulate yCD gene expression in CEA-expressing cells in vivo. Such tumor-specific expression should prove useful in colorectal cancer gene therapy to achieve selective prodrug conversion in tumors.     

Risk of lung carcinoma among users of nonsteroidal antiinflammatory drugs

BACKGROUND: Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit the development of lung tumors in experimental animals. To the authors' knowledge there are little data regarding whether regular use of NSAIDs reduces the risk of developing lung carcinoma in humans. METHODS: The association between lung carcinoma risk and regular use of NSAIDs, including aspirin, was evaluated in a hospital-based case-control study of 1038 patients and 1002 controls. RESULTS: The relative risk estimate of lung carcinoma associated with using NSAIDs 3 times a week or more for 1 or more years demonstrated an odds ratio (OR) of 0.68 (95% confidence interval [95% CI], 0.53-0.89). Results were similar when separated by lung histologic type. The association varied by smoking status. The OR was 1.28 (95% CI, 0.73-2.25) in never-smokers and 0.60 (95% CI 0.45-0.80) in ever-smokers. The smoking-specific risk estimates for aspirin were similar to those for all NSAIDs. CONCLUSIONS: The results of the current study suggest a possible chemoprotective benefit with the use of NSAIDs among individuals who are former or current smokers.