Citations

Background— Caveolin-1 is a regulator of signaling events originating from plasma membrane microdomains termed caveolae. This study was performed to determine the regulatory role of caveolin-1 on the proliferative events induced by platelet-derived growth factor (PDGF) in vascular smooth muscle cells (VSMCs). Methods and Results— Treatment of VSMCs with PDGF for 24 hours resulted in a loss of caveolin-1 protein expression and plasma membrane–associated caveolae, despite a 3-fold increase in caveolin-1 mRNA. Pretreatment of VSMCs with chloroquine, an inhibitor of lysosomal function, inhibited the PDGF-induced loss of caveolin-1. These studies demonstrated that caveolin-1 was a target of PDGF signaling events. Adenoviral overexpression of caveolin-1 was associated with a switch in PDGF-induced signaling events from a proliferative response to an apoptotic response. This overexpression inhibited PDGF-induced expression of cyclin D1 in the presence of unaffected mitogen-activated protein kinase activation. Conclusions— Taken together, these studies suggest that caveolin-1 is an inhibitor of PDGF proliferative responses and might be capable of transforming PDGF-induced proliferative signals into death signals.

AbstractMultiple myeloma is a disseminated neoplasm of terminally differentiated plasma cells that is incurable with currently available therapies. Although the disease is radiosensitive, external beam radiation leads to significant toxicity due to sensitive end-organ damage. Thus, genetic approaches for therapy are required. We hypothesized that the incorporation of immunoglobulin promoter and enhancer elements in a self-inactivating (SIN) lentiviral vector should lead to specific and high-level transgene expression in myeloma cells. A SIN lentivector with enhanced green fluorescent protein (EGFP) expression under the control of a minimal immunoglobulin promoter as well as the Kappa light chain intronic and 3′ enhancers transduced myeloma cell lines with high efficiency (30%-90%). EGFP was expressed at a high level in myeloma cells but silent in all nonmyeloma cell lines tested compared with the cytomegalovirus (CMV) promoter/enhancer. Transduction of myeloma cells with the targeted vector coding for the human sodiumiodide symporter (hNIS) led to hNIS expression by these cells allowing them to concentrate radioiodine up to 18-fold compared with controls. Tumor xenografts in severe combined immunodeficiency mice expressing hNIS could be imaged using iodine-123 (123I) and shown to retain iodide for up to 48 hours. These tumor xenografts were completely eradicated by a single dose of the therapeutic isotope iodine-131 (131I) without evidence of recurrence up to 5 months after therapy. We conclude that lentivectors can be transcriptionally targeted for myeloma cells and the use of hNIS as a therapeutic gene for myeloma in combination with 131I needs further exploration.

SUMMARY We previously described autoantibodies against a UGA serine tRNA–protein complex (tRNP(Ser)Sec) in patients with type-1 autoimmune hepatitis [1] and now define the specificity and frequency of this autoantibody and the DNA sequence encoding the tRNA(Ser)Sec-associated antigenic protein. The presence of anti-tRNP(Ser)Sec antibodies was highly specific for type-1 autoimmune hepatitis, as 47·5% of patients were positive compared with none of the control subjects. To characterize the antigenic protein(s), we immunoscreened a human cDNA library with anti-tRNP(Ser)Sec-positive sera. Two clones (19 and 13) were isolated. Clone 19 encodes a protein with a predicted molecular mass of 48·8 kD. Clone 13 is a shorter cDNA, almost identical to clone 19, which encodes a 35·9-kD protein. Expression of both cDNAs was accomplished in Escherichia coli as His-tagged recombinant proteins. Antibodies eluted from both purified recombinant proteins were able to immunoprecipitate the tRNA(Ser)Sec from a HeLa S3 cell extract, demonstrating their cross-reactivity with the mammalian antigenic complex. Recent cloning data relating to the target antigen(s) of autoantibodies in autoimmune hepatitis patients that react with a soluble liver antigen (SLA) and a liver-pancreas antigen (LP) have revealed that these two autoantibodies are identical and that the cloned antigen shows 99% amino acid sequence homology with tRNP(Ser)Sec.

Purpose: To determine whether (1) tailored nicotine patch therapy that is based on smoking rate can be carried out in a multisite oncology investigative group practice setting, (2) long-term use of bupropion reduces the rate of relapse to smoking in smokers who stop smoking with nicotine patch therapy, and (3) bupropion can initiate smoking abstinence among smokers who have failed to stop smoking after nicotine patch therapy. Participants and Methods: Fourteen North Central Cancer Treatment Group sites recruited generally healthy adult smokers from the general population for nicotine patch therapy and based the patch dosage on smoking rates. At completion of nicotine patch therapy, nonsmoking participants were eligible to be assigned to bupropion or placebo for 6 months (for relapse prevention). and smoking participants were eligible to be assigned to bupropion or placebo for 8 weeks of treatment. Results: Of 578 subjects, 31% were abstinent from smoking at the end of nicotine patch therapy. Of those subjects not smoking at the end of nicotine patch therapy who entered the relapse prevention phase, 28% and 25% were not smoking at 6 months (the end of the medication phase) for bupropion and placebo, respectively (P = .73). For those still smoking at the end of nicotine patch therapy, 3.1% and 0.0% stopped smoking with bupropion or placebo, respectively (P = .12). Conclusion: Tailored nicotine patch therapy for the general population of smokers can be provided in a multisite oncology investigative group setting. Bupropion did not reduce relapse to smoking in smokers who stopped smoking with nicotine patch therapy. Bupropion did not initiate abstinence among smokers who failed to stop smoking with nicotine patch therapy.

ABSTRACT A 45-year-old man from Nepal with a 13-year history of polycystic kidney disease was diagnosed as suffering from chronic renal failure with end-stage renal disease. After receiving empirical antituberculosis treatment, he was treated with broad-spectrum antibiotics. A left nephrectomy was performed, and after 4 months, he received a kidney transplant. The left kidney was grossly enlarged, with multiple cystic spaces filled with blackish material. Histologic examination of the excised left kidney tissue stained with hematoxylin and eosin and Gomori's methenamine silver stains showed numerous hyaline, septate, fungal hyphae of various lengths, many broken into rectangular arthroconidia in the cystic spaces. Culture of the kidney tissue yielded white, glabrous, yeast-like colonies. Based on its micromorphology, growth at 42°C, and ribosomal DNA (rDNA) sequence analysis, and also sequence analysis of the internal-transcribed-spacer and D1/D2 rDNA regions, the yeast was identified as Trichosporon loubieri. Postsurgically, the patient was treated with amphotericin B and oral itraconazole, followed by maintenance therapy with fluconazole. He remained afebrile and asymptomatic. At the final follow-up, all parameters were found normal and the patient was doing well, with normal renal function reports. This paper presents the first known case of human infection caused by T. loubieri.

PURPOSE: To evaluate quality of life (QOL) and tumor response after administration of an oral chemotherapy regimen in patients with previously untreated metastatic colorectal cancer. PATIENTS AND METHODS: Seventy-eight patients received a mean number of 5.8 cycles of therapy. QOL data were analyzed at baseline, after every two cycles of therapy, and at the time of treatment discontinuation. The Uniscale and the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire C30 were both utilized. RESULTS: The confirmed response rate was 26% (95% confidence interval [CI], 17% to 37%). Median survival was 11.3 months (95% CI, 9.6 to 15.1 months). Global QOL scores were unchanged over the course of therapy by either tool. Only the physical function subscale score had worsened at the end of therapy. In an analysis of responding patients, significant and durable improvements in both global QOL measures as well as select subscale scores were observed. Diarrhea and physical function QOL scores had declined at the time of treatment discontinuation. Patients who did not respond to therapy had preserved QOL scores when they were evaluated after two cycles of therapy. CONCLUSION: This oral treatment strategy preserved QOL in treated patients. Global QOL measures as well as several QOL subscale scores significantly improved in patients with a documented response to therapy. The profile of improved QOL components indicated that patient well-being was related to tumor response in specific and perceivable ways. Nonresponding patients reported preserved QOL during the first two cycles of therapy. QOL analysis was feasible and informative in this moderately sized multicenter phase II trial.

ABSTRACT Caveolin-1 (Cav-1) is a major protein constituent of caveolae, a type of plasma membrane raft. We observed that coexpression of human Cav-1 with human immunodeficiency virus type 1 (HIV-1) blocked virion production from cells that are ordinarily highly permissive. Further investigation showed that this effect is specific, occurs at low ratios of Cav-1 to HIV-1 DNA, depends on expression of Cav-1 protein, and involves severely impaired expression of HIV-1 proteins. Cav-1 also blocked HIV-2 expression. In contrast, Cav-1 did not inhibit protein expression by a paramyxovirus and did not induce apoptosis or affect cellular morphology, cell viability, or cell cycle progression. Although only small amounts of HIV-1 virions were released from Cav-1-transfected cells, these were fully infectious. Deletion mutagenesis showed that the C-terminal 78 residues were as active as the full-length (178-amino-acid) protein in producing the block. In contrast, the 100 most N-terminal amino acids of Cav-1, which include the previously identified oligomerization and scaffolding domains, were shown to be dispensable. Study of single-amino-acid-exchange mutants of Cav-1 established that palmitoylation was not required. Additional deletion mutants then identified the hydrophobic, membrane-associated domain (residues 101 to 135) as the main determinant. Cellular distribution of wild-type and mutant proteins correlated with ability to block HIV-1 expression. Finally, Cav-2 also blocked HIV-1 expression. These data show that coexpression of caveolins can markedly inhibit expression of HIV proviral DNA and establish that the inhibition is mediated by the hydrophobic, membrane-associated domain.

ABSTRACT Six clinical isolates of the nonpigmented, rapidly growing species Mycobacterium mageritense were recovered from sputum, bronchial wash, blood, sinus drainage, and two surgical wound infections from separate patients in Texas, New York, Louisiana, and Florida. The isolates matched the ATCC type strain by PCR restriction enzyme analysis of the 65-kDa hsp gene sequence of Telenti, high-performance liquid chromatography, biochemical reactions, and partial 16S rRNA gene sequencing. These are the first isolates of this species to be described in the United States and the first isolates to be associated with clinical disease. Susceptibility testing of all known isolates of the species revealed all isolates to be susceptible or intermediate to amikacin, cefoxitin, imipenem, and the fluoroquinolones and sulfonamides but resistant to clarithromycin. Because of their phenotypic and clinical similarity to isolates of the Mycobacterium fortuitum third biovariant complex (sorbitol positive), isolates of M. mageritense are likely to go undetected unless selected carbohydrate utilization or molecular identification methods are used.

Many of the mechanisms that govern T-cell homeostasis remain obscure. Here we report that repeated administration of synthetic oligodeoxynucleotides containing unmethylated cytosine-guanine motifs (CpG-ODN) into mice induces a systemic antigen-independent expansion of naive and memory T cells in a full T-cell compartment. Expansion of T cells was observed on both CD4+ and CD8+ T-cell subsets and was produced not by inducing the proliferation of the cells but by preventing their death. The antiapoptotic effects of CpG-ODN on T cells were observed against activation-induced death and growth factor withdrawal–mediated death. The ability of CpG-ODN to protect T cells from these forms of death was associated with the up-regulation of antiapoptotic gene products including c-FLIP, bcl-xL, and, to some extent, bcl-2. The effect of CpG-ODN on naive and memory T cells required the expression of CD28 and was not dependent on the presence of B lymphocytes, suggesting that other antigen-presenting cells that respond to CpG-ODN, such as dendritic cells, may provide antiapoptotic signals to T cells in an antigen-independent but CD28/B7-dependent fashion. The present findings suggest that CpG-ODN can disrupt normal T-cell homeostasis not by acting as a mitogen but by preventing T-cell death that normally takes place as a mechanism to maintain steady-state levels of T cells. These findings support a potential means to expeditiously replenish and maintain the peripheral lymphocyte population after severe immunodepletion such as that which occurs in HIV-infected individuals and individuals undergoing cytoablative therapies.