La autoantigen enhances and corrects aberrant translation of poliovirus RNA in reticulocyte lysate

Translation initiation on poliovirus RNA occurs by internal binding of ribosomes to a sequence within the 5' untranslated region. We have previously characterized a HeLa cell protein, p52, that binds to a fragment of the poliovirus 5' untranslated region (K. Meerovitch, J. Pelletier, and N. Sonenberg, Genes Dev. 3:1026-1034, 1989). Here we report the purification of the HeLa p52. Protein microsequencing identified p52 as La autoantigen. The La protein is a human antigen that is recognized by antibodies from patients with autoimmune disorders such as systemic lupus erythematosus and Sjögren's syndrome. We show that the La protein stimulates translation of poliovirus RNA, but not brome mosaic virus, tobacco mosaic virus, and alfalfa mosaic virus 4 RNA, translation in a reticulocyte lysate. In addition, La corrects aberrant translation of poliovirus RNA in a reticulocyte lysate. Subcellular immunolocalization showed that La protein is mainly nuclear, but after poliovirus infection, La is redistributed to the cytoplasm. Our results suggest that La protein is involved in poliovirus internal initiation of translation and might function through a similar mechanism in the translation of cellular mRNAs.

A 52-kD protein is a novel component of the SS-A/Ro antigenic particle

Anti-SS-A/Ro autoantibodies are found in the sera of patients with Sjogren's syndrome (SS) and SLE. In the course of analyzing 61 SS patients for their autoantibody profiles, we found that 42 were positive for anti-SS-A by double diffusion in agarose and demonstrated precipitin lines identical to that produced by a prototype anti-SS-A serum. Further analysis of these SS-A antibody-positive sera by Western blotting of cell extracts revealed that 21 sera reacted with two proteins of 60 and 52 kD, 13 sera reacted with 52-kD protein, two detected only 60 kD, while six were nonreactive. Affinity-purified anti-60-kD and anti-52-kD antibodies reacted exclusively with their corresponding antigens. Partial proteolysis of these proteins did not reveal common degradation fragments. Thus the 52- and 60-kD proteins were found to be antigenically and apparently structurally distinct from each other. They were also distinct from 48-kD SS-B/La protein. In immunoprecipitation using labeled cell extracts, affinity-purified anti-52-kD antibodies brought down the 52-kD protein as well as the 60-kD band. In [32P]orthophosphate-labeled HeLa cell extract both antibodies precipitated the same spectrum of small RNAs (hYl-5). In indirect immunofluorescence, anti-52-kD and anti-60-kD antibodies immunolocalized in similar subcellular structures and showed similar punctate nuclear staining patterns. Western blot analysis revealed that both proteins were present in lymphocytic as well as epithelial human cell lines tested. The data above define a new antigen of 52 kD which is another component of the SS-A particle and is associated in complex formation with the previously reported 60-kD protein.

Human autoantibody to a novel protein of the nuclear coiled body: immunological characterization and cDNA cloning of p80-coilin

Antibodies producing an unusual immunofluorescent pattern were identified in the sera of patients with diverse autoimmune features. This pattern was characterized by the presence of up to six round discrete nuclear bodies in interphase cell nuclei. Immunoblotting analysis showed that these sera recognized an 80-kD nuclear protein, and affinity-purified anti-p80 antibody from the protein band reproduced the fluorescent staining of nuclear bodies. Colloidal gold immunoelectron microscopy showed that the affinity-purified anti-p80 antibody recognized the coiled body, an ultramicroscopic nuclear structure probably first described by the Spanish cytologist Ramon y Cajal. Five cDNA clones were isolated from a MOLT-4 cell lambda gt-11 expression library using human antibody and oligonucleotide probes. The longest cDNA insert was 2.1 kb and had an open reading frame of 405 amino acids. A clone encoding a 14-kD COOH-terminal region of the protein was used for expression of a beta-galactosidase fusion protein. An epitope was present in this COOH-terminal 14-kD region, which was recognized by 18 of 20 sera with anti-p80 reactivity, and affinity-purified antibody from the recombinant protein also reacted in immunofluorescence to show specific staining of the coiled body. This is the first demonstration and molecular cloning of a protein that appears to have particular identification with the coiled body, and it was designated p80-coilin. Autoantibody to p80-coilin may be useful for the elucidation of the structure and function of the coiled body, and the availability of a cDNA sequence could be helpful in further studies to clarify the clinical significance of this autoantibody response.

Genetic and physical mapping of the Lps locus: identification of the toll-4 receptor as a candidate gene in the critical region

On the basis of 2093 meioses analyzed in two separate intraspecific backcrosses, the location of the mouse Lpsd mutation was circumscribed to a genetic interval 0.9 cM in size. A total of 19 genetic markers that lie in close proximity to the mutation were examined in mapping. Most of these were previously unpublished polymorphic microsatellites, identified by fragmentation of YAC and BAC clones spanning the region of interest. Lpsd was found to be inseparable from the microsatellite marker D4MIT178, and from three novel polymorphic microsatellites identified near D4MIT178. The mutation was confined between two novel microsatellite markers, herein designated "B" and "83.3." B lies centromeric to the mutation, and was separated by four crossovers in a panel of 1600 mice; 83.3 lies distal to the mutation and was separated by three crossovers in a panel of 493 mice. 66 BAC clones and one YAC clone were assembled to cover > 95% of the critical region. Estimates based on pulsed field gel electrophoresis and fluorescence in situ hybridization indicate that the The B-->83.3 interval is about 3.2 Mb in length. A minimal area of zero recombinational distance from Lpsd was also assigned, and found to occupy approximately 1.2 Mb of physical size. To identify gene candidates, nearly 40,000 sequencing runs were performed across the critical region. Selective hybridization and exon trapping were also employed to identify genes throughout the "zero" region. Only a single intact gene was identified within the entire critical region. This gene encodes the Toll-4 receptor, a member of the IL-1 receptor family.

A three-dimensional MRI atlas of the mouse brain with estimates of the average and variability

Although there is growing interest in finding mouse models of human disease, no technique for quickly and quantitatively determining anatomical mutants currently exists. Magnetic resonance imaging (MRI) is ideally suited to probe fine structures in mice. This technology is three-dimensional, non-destructive and rapid compared to histopathology; hence MRI scientists have been able to create detailed three-dimensional images of 60 mum resolution or better. The data is digital which lends itself to sophisticated image processing algorithms. Here we show a variational MRI atlas constructed from nine excised brains of 8 week old 129S1/SvImJ male mice. This new type of atlas is comprised of an unbiased average brain--created from alignment of the individual brains--and the mathematical descriptors of anatomical variation across the individuals. We found that the majority of internal points in the individuals never varied more than 117 microm from equivalent points in the atlas. A three-dimensional annotation of the average image was performed and used to estimate the mean and standard deviation of volumes in a variety of structures across the individual brains; these volumes never differed by more than 5%. Our results indicate that variational atlases of inbred strains represent a well-defined basis against which mutant outliers can be readily compared.

Immunological and ultrastructural studies of the nuclear coiled body with autoimmune antibodies

Studies with human autoimmune sera identified auto-antibodies reacting with a novel antigen of 80 kDa. In interphase mammalian cells, the 80-kDa antigen was enriched in nuclear coiled bodies and was used as a marker for this nuclear structure. This antigen was subsequently named p80-coilin. By light and electron microscopic immunocytochemistry, a number of other antigens were also localized to the coiled body, including components of small nuclear ribonucleoproteins which are involved in the processing of nucleolar and extranucleolar RNA. Although the function of the coiled body is unknown, the presence of these subcellular particles might indicate an involvement in RNA metabolism. The identification of a protein highly enriched in this structure and the availability of specific antibodies might help in its isolation and the study of its function.

Molecular definition and sequence motifs of the 52-kD component of human SS-A/Ro autoantigen

Serum SS-A/Ro autoantibodies are commonly found in patients with Sjogren's syndrome, systemic lupus erythematosus, neonatal lupus, and subacute cutaneous lupus. Two proteins of 60 and 52 kD have been described as targets for these autoantibodies. To define the 52-kD component unambiguously, cDNA clones were isolated from human HepG2 and MOLT-4 cell cDNA libraries. The identity of cDNA was established by (a) the specificity of the antibody affinity purified from the recombinant protein, (b) the reactivity of the purified recombinant protein with prototype SS-A/Ro sera in immunoblot and ELISA, and (c) two-dimensional gel comigration of MOLT-4 cell 52-kD protein and the recombinant protein. A 1.9-kb cDNA encoded the complete 52-kD protein containing 475 amino acids (Mr 54,082). Putative zinc-finger domains and a leucine zipper motif were identified in the amino-terminal half of the 52-kD protein, implicating its possible association with DNA/RNA. Sequence homology detected between the 52-kD protein and human ret transforming protein, and mouse T cell gene expression down-regulatory protein rpt-1, may provide leads to the functional role of the 52-kD protein in addition to the possibility that these proteins might constitute members of a subfamily of finger proteins.

Identification and characterization of a family of Rab11-interacting proteins

Rab11a is a small GTP-binding protein enriched in the pericentriolar plasma membrane recycling systems. We hypothesized that Rab11a-binding proteins exist as downstream effectors of its action. Here we define a family of four Rab11-interacting proteins: Rab11-Family Interacting Protein 1 (Rab11-FIP1), Rab11-Family Interacting Protein 2 (Rab11-FIP2), Rab11-Family Interacting Protein 3 (Rab11-FIP3), and pp75/Rip11. All four interacting proteins associated with wild type Rab11a and dominant active Rab11a (Rab11aS20V) as well as Rab11b and Rab25. Rab11-FIP2 also interacted with dominant negative Rab11a (Rab11aS25N) and the tail of myosin Vb. The binding of Rab11-FIP1, Rab11-FIP2, and Rab11-FIP3 to Rab11a was dependent upon a conserved carboxyl-terminal amphipathic alpha-helix. Rab11-FIP1, Rab11-FIP2, and pp75/Rip11 colocalized with Rab11a in plasma membrane recycling systems in both non-polarized HeLa cells and polarized Madin-Darby canine kidney cells. GFP-Rab11-FIP3 also colocalized with Rab11a in HeLa cells. Rab11-FIP1, Rab11-FIP2, and pp75/Rip11 also coenriched with Rab11a and H(+)K(+)-ATPase on parietal cell tubulovesicles, and Rab11-FIP1 and Rab11-FIP2 translocated with Rab11a and the H(+)K(+)-ATPase upon stimulating parietal cells with histamine. The results suggest that the function of Rab11a in plasma membrane recycling systems is dependent upon a compendium of protein effectors.

Antinuclear antibodies (ANAs): diagnostically specific immune markers and clues toward the understanding of systemic autoimmunity

The convergence of studies in the clinical and basic sciences has resulted in the definitive identification of many intracellular antigens which are the targets of autoantibodies in patients with systemic lupus erythematosus, scleroderma, dermatomyositis/polymyositis, Sjogren's syndrome, mixed connective tissue disease, and drug-induced autoimmunity. Some of this new knowledge includes the identification of the Sm and RNP antigens as ribonucleoprotein particles involved in splicing of precursor messenger RNA, Scl-70 as DNA topoisomerase I, proliferating cell nuclear antigen as auxiliary protein of DNA polymerase delta, and certain antigens in myositis as aminoacyl transfer RNA synthetases. This information confirms, at a molecular level, the presence of specific profiles of autoimmune responses so that autoantibodies can be used in clinical medicine as diagnostically useful immune markers. In addition the data give compelling reasons to consider that certain autoimmune diseases are antigen-driven. Many auto-antibodies have the interesting feature of recognizing epitopes on the antigens which are active or functional sites of the molecule. It is suggested that the data provide clues to the nature of the intracellular particle initiating the immune response and may help to elucidate some of the early mechanisms of the autoimmune process.

Clinical relevance of HEp-2 indirect immunofluorescent patterns: the International Consensus on ANA patterns (ICAP) perspective

The indirect immunofluorescence assay (IIFA) on HEp-2 cells is widely used for detection of antinuclear antibodies (ANA). The dichotomous outcome, negative or positive, is integrated in diagnostic and classification criteria for several systemic autoimmune diseases. However, the HEp-2 IIFA test has much more to offer: besides the titre or fluorescence intensity, it also provides fluorescence pattern(s). The latter include the nucleus and the cytoplasm of interphase cells as well as patterns associated with mitotic cells. The International Consensus on ANA Patterns (ICAP) initiative has previously reached consensus on the nomenclature and definitions of HEp-2 IIFA patterns. In the current paper, the ICAP consensus is presented on the clinical relevance of the 29 distinct HEp-2 IIFA patterns. This clinical relevance is primarily defined within the context of the suspected disease and includes recommendations for follow-up testing. The discussion includes how this information may benefit the clinicians in daily practice and how the knowledge can be used to further improve diagnostic and classification criteria.

The changing preference of T and B cells for partners as T-dependent antibody responses develop

Recirculating virgin CD4+ T cells spend their life migrating between the T zones of secondary lymphoid tissues where they screen the surface of interdigitating dendritic cells. T-cell priming starts when processed peptides or superantigen associated with class II MHC molecules are recognised. Those primed T cells that remain within the lymphoid tissue move to the outer T zone, where they interact with B cells that have taken up and processed antigen. Cognate interaction between these cells initiates immunoglobulin (Ig) class switch-recombination and proliferation of both B and T cells; much of this growth occurs outside the T zones B cells migrate to follicles, where they form germinal centres, and to extrafollicular sites of B-cell growth, where they differentiate into mainly short-lived plasma cells. T cells do not move to the extrafollicular foci, but to the follicles; there they proliferate and are subsequently involved in the selection of B cells that have mutated their Ig variable-region genes. During primary antibody responses T-cell proliferation in follicles produces many times the peak number of T cells found in that site: a substantial proportion of the CD4+ memory T-cell pool may originate from growth in follicles.

Use of an agent to reduce scattering in skin

BACKGROUND AND OBJECTIVE

A method to increase light transport deeply into target areas of tissue would enhance both therapeutic and diagnostic laser applications. The effects of a hyperosmotic agent on the scattering properties of rat and hamster skin were investigated.

STUDY DESIGN/MATERIALS AND METHODS

A hyperosmotic agent, glycerol, was applied in vitro and in vivo to rat and hamster skin to assess the changes in tissue optical properties. Changes in the reduced scattering coefficient after application of the agent in vitro to rat skin and after the skin has been rehydrated were assessed to evaluate the effect of the agent on tissue.

RESULTS

Experimental results showed a transient change in the optical properties of in vitro rat skin. A 50% increase in transmittance and decrease in diffuse reflectance occurred within 5-10 min after the introduction of anhydrous glycerol. In addition, reduction of light scattering with this technique increased depth of visibility with optical coherence tomography. Injection of glycerol under the skin allowed in vivo visualization of blood vessels.

CONCLUSIONS

The application of the agent reduces the amount of refractive mismatch found in the tissue and markedly reduces random scattering, thereby making the skin less turbid for visible wavelengths for a controlled period of time.

MEK kinase 1 gene disruption alters cell migration and c-Jun NH2-terminal kinase regulation but does not cause a measurable defect in NF-kappa B activation

MEK kinase 1 (MEKK1) is a 196-kDa mitogen-activated protein kinase (MAPK) kinase kinase that, in addition to regulating the c-Jun NH(2)-terminal kinase (JNK) pathway, is involved in the control of cell motility. MEKK1(-/-) mice are defective in eyelid closure, a TGFalpha-directed process involving the migration of epithelial cells. MEKK1 expression in epithelial cells stimulates lamellipodia formation, a process required for cell movement. In addition, mouse embryo fibroblasts derived from MEKK1(-/-) mice are inhibited in their migration relative to MEKK1(+/+) fibroblasts. MEKK1 is required for JNK but not NF-kappaB activation in response to virus infection, microtubule disruption, and stimulation of embryonic stem cells with lysophosphatidic acid. MEKK1 is not required for TNFalpha or IL-1 regulation of JNK or NF-kappaB activation in macrophages or fibroblasts. Thus, MEKK1 senses microtubule integrity, contributes to the regulation of fibroblast and epithelial cell migration, and is required for activation of JNK but not NF-kappaB in response to selected stress stimuli.

Residual Cajal bodies in coilin knockout mice fail to recruit Sm snRNPs and SMN, the spinal muscular atrophy gene product

Cajal bodies (CBs) are nuclear suborganelles involved in the biogenesis of small nuclear ribonucleoproteins (snRNPs). In addition to snRNPs, they are highly enriched in basal transcription and cell cycle factors, the nucleolar proteins fibrillarin (Fb) and Nopp140 (Nopp), the survival motor neuron (SMN) protein complex, and the CB marker protein, p80 coilin. We report the generation of knockout mice lacking the COOH-terminal 487 amino acids of coilin. Northern and Western blot analyses demonstrate that we have successfully removed the full-length coilin protein from the knockout animals. Some homozygous mutant animals are viable, but their numbers are reduced significantly when crossed to inbred backgrounds. Analysis of tissues and cell lines from mutant animals reveals the presence of extranucleolar foci that contain Fb and Nopp but not other typical nucleolar markers. These so-called "residual" CBs neither condense Sm proteins nor recruit members of the SMN protein complex. Transient expression of wild-type mouse coilin in knockout cells results in formation of CBs and restores these missing epitopes. Our data demonstrate that full-length coilin is essential for proper formation and/or maintenance of CBs and that recruitment of snRNP and SMN complex proteins to these nuclear subdomains requires sequences within the coilin COOH terminus.

Amphotropic host range of naturally occuring wild mouse leukemia viruses

Seven murine leukemia virus field isolates (uncloned) from wild mice (Musmusculus) of four widely separated areas in southern California show an unusually wide in vitro host range. They replicate well in human, feline, canine, guinea pig, rabbit, rat, and mouse cells, whereas bovine, hamster, and avian cells are resistant. Since this host range includes that of both mouse tropic (ecotropic) and xenotropic murine leukemia viruses, they are designated as "amphotropic". No purely xenotropic virus component is detectable in these field isolates. They may represent the "wild" or ancestral viruses from which the ecotropic and xenotrophic murine leukemia virus strains of laboratory mice have been derived.

An international outbreak of salmonellosis associated with raw almonds contaminated with a rare phage type of Salmonella enteritidis

During the winter of 2000 to 2001, an outbreak due to Salmonella Enteritidis (SE) phage type 30 (PT30), a rare strain, was detected in Canada. The ensuing investigation involved Canadian and American public health and food regulatory agencies and an academic research laboratory. Enhanced laboratory surveillance, including phage typing and pulsed-field gel electrophoresis, was used to identify cases. Case questionnaires were administered to collect information about food and environmental exposures. A case-control study with 16 matched case-control pairs was conducted to test the hypothesis of an association between raw whole almond consumption and infection. Almond samples were collected from case homes, retail outlets, and the implicated processor, and environmental samples were collected from processing equipment and associated farms for microbiological testing. One hundred sixty-eight laboratory-confirmed cases of SE PT30 infection (157 in Canada, 11 in the United States) were identified between October 2000 and July 2001. The case-control study identified raw whole almonds as the source of infection (odds ration, 21.1; 95% confidence interval, 3.6 to infinity). SE PT30 was detected in raw whole natural almonds collected from home, retail, distribution, and warehouse sources and from environmental swabs of processing equipment and associated farmers' orchards. The frequent and prolonged recovery of this specific organism from a large agricultural area was an unexpected finding and may indicate significant diffuse contamination on these farms. Identification of almonds as the source of a foodborne outbreak is a previously undocumented finding, leading to a North American recall of this product and a review of current industry practices.

Osteonecrosis in patients irradiated for head and neck carcinoma

One hundred patients irradiated for cancers of the oral cavity, oropharynx, and nasopharynx were evaluated for the occurrence of osteonecrosis and associated predisposing factors. Selection was based on availability of complete dental records, a minimum of six months follow-up, and treatment fields, which included maxilla and/or mandible. Bone doses were calculated by using radiotherapy treatment records, port films, and isodose distributions. Osteonecrosis developed in 19 of 78 dentulous patients and in 3 of 22 edentulous patients. The time of development of osteonecrosis varied; in 15 cases osteonecrosis occurred more than one year after treatment. The most important risk factor for the development of osteonecrosis was the radiation dose to bone, particularly in the less vascular mandible. Osteonecrosis 7500 rads to the bone. None of the patients who received less than 6500 rads developed osteonecrosis. The risk was significantly greater when teeth were removed after therapy compared with those individuals with extractions before radiation or no extractions at all.

A novel cytoplasmic protein with RNA-binding motifs is an autoantigen in human hepatocellular carcinoma

In hepatocellular carcinoma (HCC), autoantibodies to intracellular antigens are detected in 30-40% of patients. Patients with chronic hepatitis or liver cirrhosis develop HCC, and when this occurs, some patients exhibit autoantibodies of new specificities. It has been suggested that these novel autoantibody responses may be immune system reactions to proteins involved in transformation-associated cellular events. One HCC serum shown to contain antibodies to unidentified cellular antigens was used to immunoscreen a cDNA expression library, and a full length cDNA clone was isolated with an open reading frame encoding 556 amino acids with a predicted molecular mass of 62 kD. The 62-kD protein contained two types of RNA-binding motifs, the consensus sequence RNA-binding domain (CS-RBD) and four hnRNP K homology (KH) domains. This protein, provisionally called p62, has close identity (66-70%) to three other proteins at the amino acid sequence level, and all four proteins may belong to a family having CS-RBD in the NH2-terminal region and four KH domains in the mid-to-COOH- terminal region. The homologous proteins are: KH domain-containing protein overexpressed in cancer (Koc); zipcode binding protein, a protein which binds to a conserved nucleotide element in chicken beta-actin mRNA (ZBP1); and a protein which binds to a promoter cis element in Xenopus laevis TFIIIA gene (B3). p62 protein is cytoplasmic in location, and autoantibodies were found in 21% of a cohort of HCC patients. Patients with chronic hepatitis and liver cirrhosis, conditions which are frequent precursors to HCC, were negative for these autoantibodies, suggesting that the immune response might be related to cellular events leading to transformation. However, the possible involvement of p62 autoantigen as a factor in the transformation process remains to be elucidated.

Immunocytochemical analysis of the coiled body in the cell cycle and during cell proliferation

Coiled bodies (CBs) are small, round structures found in the nucleoplasm of most eukaryotic cells. Human autoantibodies to a 80-kDa protein, p80-coilin, are immunohistologic markers for CBs. A polyclonal rabbit antiserum (R288) raised against recombinant p80-coilin was shown to have similar immunochemical properties as human autoantibodies and was used to analyze the expression of p80-coilin-associated CBs in cell cultures synchronized by double thymidine block, nocodazole arrest, serum starvation, or hormonal deprivation. By employing thymidine block and nocodazole arrest of HeLa cells, CBs were observed in immunofluorescent studies to be largest in size in the S and G2 phases of the cell cycle. These large CBs might have coalesced into one or two such structures per cell from smaller and more numerous CBs of three to eight per cell during the mid G1 phase of the cell cycle. No CB-like structures were observed in mitosis and early G1. However, immunoblotting analyses showed that the total amount of p80-coilin remained approximately the same throughout the cell cycle. When HeLa cells were separated into soluble and particulate fractions, p80-coilin was detected predominantly in the soluble fraction in mitosis and early G1, whereas it was present predominantly in the particulate fraction in late G1, S, and G2 when structurally distinct CBs were observed. In the analysis of CBs in two experimental models of cell proliferation (reversal of 3T3 serum starvation and FRTL-5 thyrotropin deprivation), proliferating cells contained larger, brighter, and more numerous CBs as well as a > 2-fold increase in the total amount of p80-coilin compared to that in quiescent cells. The expression of p80-coilin in quiescent cells induced to proliferate and the cyclic formation and breakdown of CBs might be consistent with the notion that CBs may be specialized centers related to the maturation of mRNA, but this evidence is indirect and needs further definitive study.

Autoantibodies to DFS 70 kd/transcription coactivator p75 in atopic dermatitis and other conditions

BACKGROUND

Sera of patients with atopic dermatitis (AD) were found to have autoantibodies that reacted with tissue culture cell substrates in immunohistochemistry to display a characteristic pattern of nuclear distribution of dense fine speckles. The sera also recognized a 70-kd protein on Western immunoblots, and the antigen was termed dense fine speckles 70 kd (DSF70).

OBJECTIVE

Because spontaneously occurring autoantibodies could be immune responses to proteins that might be participating in the disease process, it was of interest to identify the antigens driving the autoimmune antibody response.

METHODS

A serum containing high-titer antibodies to DFS70 was used to immunoscreen a complementary (c)DNA expression library to isolate cDNA encoding the antigen. After the cDNA was isolated, this was used to express recombinant protein to determine the prevalence of antibody in AD and other conditions.

RESULTS

Thirty percent of patients with AD were found to have antibody to recombinant DFS70 in Western immunoblots. Sixteen percent of patients with asthma and 9% of patients with interstitial cystitis had antibodies of the same specificities. The cDNA encoding DFS70 was identical to a transcription coactivator called p75, which had been shown to be required for RNA polymerase II-dependent transcription. Another important finding was that IgE antibodies to DFS70 were also present in AD sera.

CONCLUSION

It is suggested that a common basis for the presence of autoantibodies to DFS70 might be related to AD in asthma, interstitial cystitis, and other conditions. A possible role of this antigen-antibody system in pathogenesis remains to be demonstrated, but it appears to be a marker for a subset of patients with AD.

Molecular remedy of complex I defects: rotenone-insensitive internal NADH-quinone oxidoreductase of Saccharomyces cerevisiae mitochondria restores the NADH oxidase activity of complex I-deficient mammalian cells

The NDI1 gene encoding rotenone-insensitive internal NADH-quinone oxidoreductase of Saccharomyces cerevisiae mitochondria was cotransfected into the complex I-deficient Chinese hamster CCL16-B2 cells. Stable NDI1-transfected cells were obtained by screening with antibiotic G418. The NDI1 gene was shown to be expressed in the transfected cells. The expressed Ndi1 enzyme was recognized to be localized to mitochondria by immunoblotting and confocal immunofluorescence microscopic analyses. Using digitonin-permeabilized cells, it was shown that the transfected cells, but not nontransfected control cells, exhibited the electron transfer activities with glutamate/malate as the respiratory substrate. The activities were inhibited by flavone, antimycin A, and KCN but not by rotenone. Added NADH did not serve as the substrate, suggesting that the expressed Ndi1 enzyme was located on the matrix side of the inner mitochondrial membranes. Furthermore, although nontransfected cells could not survive in a medium low in glucose (0.6 mM), which is a substrate of glycolysis, the NDI1-transfected cells were able to grow in the absence of added glucose. When glycolysis is slow, either at low glucose concentrations or in the presence of galactose, respiration is required for cells to survive. The mutant cells do not survive at low glucose or in galactose, but they can be rescued by Ndi1. These results indicated that the S. cerevisiae Ndi1 was expressed functionally in CCL16-B2 cells and catalyzed electron transfer from NADH in the matrix to ubiquinone-10 in the inner mitochondrial membranes. It is concluded that the NDI1 gene provides a potentially useful tool for gene therapy of mitochondrial diseases caused by complex I deficiency.

Final results from a randomized phase 3 study of FOLFIRI {+/-} panitumumab for second-line treatment of metastatic colorectal cancer

BACKGROUND

The study 20050181 demonstrated significant improvements in progression-free survival (PFS), objective response, and a nonsignificant trend toward increased overall survival (OS) with panitumumab-FOLFIRI versus FOLFIRI alone for second-line wild-type (WT) KRAS metastatic colorectal cancer (mCRC). Updated long-term data from a prespecified descriptive analysis are reported.

PATIENTS AND METHODS

Patients receiving one prior mCRC treatment were randomly assigned (1:1) to panitumumab (6.0 mg/kg)-FOLFIRI versus FOLFIRI every 2 weeks. Co-primary end points (PFS and OS) were prospectively analyzed by tumor KRAS status.

RESULTS

One thousand one hundred and eighty-six patients were randomly assigned. In patients with WT KRAS tumors, panitumumab-FOLFIRI significantly improved PFS versus FOLFIRI [median 6.7 versus 4.9 months; hazard ratio (HR) 0.82 [95% confidence interval (CI) 0.69, 0.97]; P = 0.023]. A trend toward longer OS was observed (median 14.5 versus 12.5 months; HR 0.92 [95% CI 0.78, 1.10]; P = 0.37). Response rates improved from 10% to 36% (P < 0.0001). From post hoc analyses in patients receiving prior oxaliplatin-bevacizumab, panitumumab-FOLFIRI improved PFS (median 6.4 versus 3.7 months; HR 0.58 [95% CI 0.37, 0.90]; P = 0.014). PFS and OS appeared longer for worst-grade skin toxicity of 2-4, versus 0-1 or FOLFIRI. Safety results were as previously reported and consistent with the known toxicities with anti-epidermal growth factor receptor therapy.

CONCLUSIONS

These data confirm the primary efficacy and safety findings of this trial and support panitumumab-FOLFIRI as a second-line treatment of WT KRAS mCRC.

Endonuclease IV of Escherichia coli is induced by paraquat

The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H2O2 produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, gamma rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate are known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusually sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O2. The levels of endonuclease IV in uninduced or paraquat-treated cells were unaffected by mutations of oxyR, a H2O2-inducible gene that governs an oxidative-stress regulon. The results indicate that endonuclease IV is an inducible DNA-repair enzyme and that its induction can be mediated via the production of superoxide radicals.

Association between the nucleolus and the coiled body

By means of light and electron microscopic immunocytochemistry, we have localized p80-coilin, a specific protein marker for coiled bodies, in mammalian cell lines as well as in primary rat neuron cultures. p80-coilin-stained nuclear bodies, which also contained fibrillarin, could be subsequently silver stained by a method specific for the visualization of nucleolar organizer regions. In cycling cells, most coiled bodies were not associated with nucleoli, whereas in rat neurons such as association was frequent. The treatment of cycling cells with actinomycin D or 5,6-dichloro-1-beta-D-ribo furanosyl-benzimidazole led to nucleolar segregation and/or disintegration, and to an association of p80-coilin staining structures with nucleoli. p80-coilin-positive structures contained fibrillarin in both untreated and treated cells. These results support the opinion that there might be a special association between coiled bodies and nucleoli, particularly in neuronal cells.

Human metapneumovirus infection in the Canadian population

Human metapneumovirus (hMPV), a newly discovered paramyxovirus, has been associated with acute respiratory tract infections (ARIs) ranging from upper ARIs to severe bronchiolitis and pneumonia. Important questions remain on the contribution of hMPV to ARIs and its impact on public health. During the 2001-2002 season, we conducted a collaborative study with four provincial public health laboratories to study the prevalence of this new virus in the Canadian population. A total of 445 specimens were collected from patients of all age groups with ARIs and were tested for the presence of hMPV by reverse transcription-PCR. Of these, 66 (14.8%) tested positive for hMPV. Positive specimens were found in all age groups and in all four provinces studied. Virus activity peaked in February and March. The age range of the patients with hMPV infection was 2 months to 93 years (median age, 25 years), with similar numbers of females (35%) and males (41%). Thirty-three percent (n = 22) of hMPV-infected patients were hospitalized; of these, 27% (n = 6) had rhinitis and pneumonia, 23% (n = 5) had bronchiolitis, and 9% (n = 2) had bronchitis. The hospitalization rates were significantly higher among patients <5 years of age (P = 0.0005) and those >50 years of age (P = 0.0044) than among those 6 to 50 years of age. Phylogenetic analysis of the F gene showed that two hMPV genetic clusters were cocirculating in the 2001-2002 season, and comparison with earlier studies suggests a temporal evolutionary pattern of hMPV isolates. These results provide further evidence of the importance of hMPV in ARIs, particularly in young children and elderly individuals.