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Biomedical subjects

W N Rom

Publications and source records attributed to W N Rom.

At least 37 records · Page 2Linked to original sources
PubMed1999

Role of c-Jun N-terminal kinase 1 (JNK1) in cell cycle checkpoint activated by the protease inhibitor N-acetyl-leucinyl-leucinyl-norleucinal.

The cysteine protease inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (LLnL) inhibited the growth of the Calu-1 lung carcinoma cells and induced a prolonged cell cycle arrest in the S phase. c-Jun N-terminal kinases (JNKs) participate in cellular responses to mitogenic stimuli, environmental stresses, and apoptotic signals but its role in cell cycle checkpoint control has not been elucidated. In this report, we examined the role of JNK in LLnL-induced S phase checkpoint by overexpression of a dominant-negative mutant of JNK1 (JNK1-APF) in Calu-1 cells. Expression of high levels of JNK1-APF blocked the growth-inhibitory effects of LLnL and abrogated S phase arrest induced by LLnL. These results support the role of JNK in the activation of cell cycle checkpoint induced by LLnL.

Anisomycin↗
PubMed1999

Induction of tumor suppression and glandular differentiation of A549 lung carcinoma cells by dominant-negative IGF-I receptor.

Overexpression or activation of insulin-like growth factor I receptor (IGF-IR) has been observed in many human cancers including breast, lung, colon and gastric carcinomas. We demonstrate that inhibition of the endogenous insulin-like growth factor I receptor by stable expression of a dominant-negative IGF-IR represses the transforming activity in vitro and tumorigenicity of human lung carcinoma cells A549 in vivo. The suppression of tumorigenicity in nude mice is correlated with the induction of glandular differentiation. In addition, functional inhibition of the endogenous receptor dramatically increases the sensitivity of A549 cells to a variety of apoptotic signals including UV irradiation and proteasome inhibitors. These effects are due to the formation of a stable heterocomplex of the dominant-negative receptor with the endogenous wild type receptor which reduces the kinase activity of the latter by twofold. Thus, inhibition of the IGF-IR signaling pathway not only suppresses tumorigenicity but also enhances sensitivity to apoptosis-inducing agents. Antagonizing IGF-IR signaling by promoting tumor differentiation and enhancing sensitivity to apoptotic death are potential cancer therapeutic approaches.

Acetylcysteine↗
PubMed1999

Targeting the replication of adenoviral gene therapy vectors to lung cancer cells: the importance of the adenoviral E1b-55kD gene.

It has been proposed that an adenovirus with the E1b-55kD gene deleted has a selective advantage in replicating in cancer cells that have mutations in the p53 gene (Bischoff et al., 1996). We have explored this hypothesis in several lung cancer cell lines, and evaluated potential mechanisms that might regulate the replication of Ad338, an E1b-55kD-deleted virus, with the objective of developing a rational approach for targeting gene therapy to lung tumors. Our data show that Ad338 replicates poorly in three lung cancer cell lines with various p53 mutations (H441, H446, and Calu1), yet this virus replicates to a high level in a lung cancer cell line with wild-type p53 (A549) and in a normal lung fibroblast line (IMR90). Viral DNA replication, expression of viral proteins, and shutoff of host cell proteins were not important variables in limiting the replication of the E1b-55kD-deleted virus. However, the cell lines resistant to host cell protein shutoff were also the most resistant to the cytopathic effect induced by mutant and wild-type virus and the only cells to survive for 8 days following infection. The E1b-55kD protein clearly has an important role in viral replication beyond its interaction with p53. Thus, an E1b-55kD-deleted virus cannot be used to specifically target viral replication to p53-mutated lung cancer cells.

Adenoviridae↗
PubMed1999

Activation of NF-kappaB in Mycobacterium tuberculosis- induced interleukin-2 receptor expression in mononuclear phagocytes.

Soluble interleukin-2 receptor-alpha (IL-2Ralpha) has been reported to be increased in the sera of patients with advanced tuberculosis, and levels decline after therapy in accordance with improvement of radiologic findings. We investigated expression of the IL-2Ralpha in bronchoalveolar lavage (BAL) cells in active pulmonary tuberculosis, and evaluated the mechanism Mycobacterium tuberculosis induces in the IL-2Ralpha using the THP-1 mononuclear phagocyte cell line. We found IL-2Ralpha expression to be increased in BAL cells from involved sites of active pulmonary tuberculosis. Expression of the alpha-chain of IL-2Ralpha on peripheral blood monocytes (PBM) was induced by M. tuberculosis by flow cytometry evaluation. Northern analysis demonstrated increased IL-2Ralpha gene expression after stimulation with M. tuberculosis which was further induced by interferon-gamma (IFN-gamma). The IL-2Ralpha promoter containing the nuclear factor kappa B (NF-kappaB) site was transcriptionally induced by M. tuberculosis and this NF-kappaB site could confer inducibility to a heterologous herpes thymidine kinase (TK) promoter by M. tuberculosis. Electrophoretic mobility shift assays (EMSAs) revealed specific binding of nuclear protein to the NF-kappaB site upon induction with M. tuberculosis. Using antibodies against the p50 and p65 subunits of NF-kappaB in EMSAs, the involvement of both p50 and p65 proteins was further demonstrated. Functional expression of the IL-2Ralpha on mononuclear phagocytes in M. tuberculosis infection may play an important immunomodulatory role in the host response.

Adult↗
PubMed1999

Screening for infection and disease as a tuberculosis control measure among indigents in New York City, 1994-1997.

SETTING: Several social service agencies in New York City, and the Chest Clinic of Bellevue Hospital, a large public hospital. OBJECTIVE: To determine the utility of screening as a preventive and control measure among persons at risk for tuberculosis. DESIGN: Persons seeking social services at several private agencies in New York City were screened, and those with a positive skin test or symptoms suggestive of active tuberculosis were referred to the Chest Clinic for evaluation. RESULTS: Of 3828 persons evaluated, 20 had active tuberculosis, and 33% of the screened cohort were tuberculin skin test positive. Of 466 persons with tuberculosis infection who were evaluated, only 55 persons were given isoniazid (INH), and only 20 completed preventive therapy. Most patients who were not given INH had taken it previously, were older than 35 years, or had continuing alcohol use which made physicians reluctant to prescribe isoniazid. CONCLUSION: Screening for tuberculosis may detect a significant number of cases of active disease when the background prevalence of the disease is very high. However, screening for infection as a means to prevent future cases is unlikely to be effective unless rates of administration and completion of isoniazid preventive therapy are increased.

Adolescent↗
PubMed1998

Type I interferon induces inhibitory 16-kD CCAAT/ enhancer binding protein (C/EBP)beta, repressing the HIV-1 long terminal repeat in macrophages: pulmonary tuberculosis alters C/EBP expression, enhancing HIV-1 replication.

We have previously observed that HIV-1 replication is suppressed in uninflamed lung and increased during tuberculosis. In vitro THP-1 cell-derived macrophages inhibited HIV-1 replication after infection with Mycobacterium tuberculosis. Suppression of HIV-1 replication was associated with inhibition of the HIV-1 long terminal repeat (LTR) and induction of ISGF-3, a type I interferon (IFN)-specific transcription factor. Repression of the HIV-1 LTR required intact CCAAT/enhancer binding protein (C/EBP) sites. THP-1 cell-derived macrophages infected with M. tuberculosis, lipopolysaccharide, or IFN-beta induced the 16-kD inhibitory C/EBPbeta isoform and coincidentally repressed HIV-1 LTR transcription. C/EBPbeta was the predominant C/EBP family member produced in THP-1 macrophages during HIV-1 LTR repression. In vivo, alveolar macrophages from uninflamed lung strongly expressed inhibitory 16-kD C/EBPbeta, but pulmonary tuberculosis abolished inhibitory C/EBPbeta expression and induced a novel C/EBP DNA binding protein. Therefore, in vitro, proinflammatory stimulation produces an IFN response inhibiting viral replication by induction of a C/EBPbeta transcriptional repressor. THP-1 cell-derived macrophages stimulated with type I IFN are similar to alveolar macrophages in the uninflamed lung in vivo. In contrast, the cellular immune response in active pulmonary tuberculosis disrupts this innate immunity, switching C/EBP expression and allowing high level viral replication.

Base Sequence↗
PubMed1998

Isoniazid levels in the bronchoalveolar lavage fluid of patients with pulmonary tuberculosis.

Isoniazid (INH) is one of the most important first line drugs in the treatment of tuberculosis. We utilized high performance liquid chromatography with a hydrazone extraction technique to measure INH in bronchoalveolar lavage (BAL) fluid specimens from six patients with active pulmonary tuberculosis. We found BAL fluid INH levels to be similar to 2-h peak serum levels. The concentration of INH in BAL fluid from lobes with infiltrate was similar to the concentration of INH in BAL fluid from lobes without infiltrate (0.062 microgram/ml and 0.073 microgram/ml, respectively). After adjusting for protein concentration in the BAL fluid, INH levels in lobes with infiltrate were threefold lower than in lobes without infiltrate. The correlation between the concentration of INH in serum and BAL fluid approached significance after correcting for protein (lobes with infiltrate, r2 = 0.60 (p = 0.07); lobes without infiltrate, r2 = 0.50 (p = 0.12). INH penetrates into bronchoalveolar fluid, and concentrations of INH in the BAL fluid suggest that assessment of the INH serum concentration is adequate to evaluate bioavailability of the drug in patients with pulmonary tuberculosis.

Adult↗
PubMed1998

The gene for lysosomal protein CD63 is normal in patients with Hermansky-Pudlak syndrome.

Hermansky-Pudlak syndrome (HPS) is one of the few genetic disorders associated with severe pulmonary fibrosis. Fifty percent of affected patients die as a result of respiratory insufficiency. Fibrosis is thought to be caused by the accumulation of ceroid, an insoluble fluorescent lipoprotein, both extracellularly and in the lysosomes of alveolar macrophages. In addition to pulmonary fibrosis, HPS is characterized by oculocutaneous albinism and a reduction in the number of platelet dense bodies. CD63 is a protein that was described originally in platelet lysosomes. It localizes to the membranes of melanosomes and platelet dense bodies. CD63 is decreased dramatically in the lysosomes and dense bodies of patients with HPS. We theorized that CD63, a membrane protein common to lysosomes, melanosomes, and platelet dense bodies, may play a role in HPS. We sought to characterize the gene coding for this protein in HPS lymphoid cell lines. The coding region for CD63 was sequenced in control and HPS cell lines. Messenger RNA from HPS and normal cell lines was examined by Northern analysis. Genomic DNA from the same cell lines was examined by Southern analysis and polymerase chain reaction (PCR). CD63 protein in lymphoid cell lines and peripheral blood monocytes was compared by Western analysis. We found no mutations in the coding region of CD63 in an HPS cell line. We also found no diminution in the quantity of CD63 RNA by Northern analysis and no gross defects in the structural gene by PCR and Southern analysis, suggesting that the CD63 structural gene, promoter, and untranslated regions were normal. Western analysis showed that the 43-kDa protein was present in control and HPS lymphoid cell lines and peripheral blood monocytes in equivalent amounts. Although CD63 is an attractive candidate for the primary defect of HPS, the disease is probably not caused by a mutation in the CD63 gene.

Adult↗
PubMed1998

Angular and fibrous particles in lung in relation to silica-induced diseases.

INTRODUCTION: The lung concentration of angular and fibrous particles was measured in cases of lung fibrosis only, in cases of lung fibrosis and lung cancer, and in cases of lung cancer only. These patients worked in different trades (mining, foundries, construction and were not a homogeneous group of exposed workers. MATERIAL AND METHODS: Particles, both angular and fibrous, were extracted from lung parenchyma by a bleach digestion method, mounted on copper microscopic grids by a carbon replica technique, and analyzed by transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS). The quartz concentration was also determined by X-ray diffraction (XRD) on a silver membrane filter after extraction from the lung parenchyma. RESULTS: (1) Lung cancer and lung fibrosis cases retained more metal-rich particles (P = 0.02) and more angular particles of all sorts (P = 0.009) than did lung fibrosis cases only, and the differences were statistically significant. (2) However, more quartz was retained in the lungs in lung fibrosis cases than in lung fibrosis or lung cancer cases, but the difference in the concentrations was not statistically significant. (3) More ferruginous bodies were retained in the lungs in lung cancer and lung fibrosis cases than in cases of lung fibrosis only, and the difference in the concentrations was statistically significant (P = 0.02). CONCLUSION: Results obtained from lung tissue must always be interpreted cautiously. However, these results are consistent with the hypothesis that workers in some trades such as foundries were exposed not only to quartz but also to asbestos, ceramic fibers, metal-rich non fibrous particles, and other likely carcinogenic chemicals. The wide range of particle types identified in the lungs of these workers illustrates the complexity of trying to determine disease origins in these work environments. Epidemiology studies have to control for the exposure to these carcinogens as well as for smoking habits.

Aged↗
PubMed1998

Local immune responses correlate with presentation and outcome in tuberculosis.

Local cellular immune responses may affect presentation and outcome in tuberculosis (TB). To investigate this hypothesis, we performed bronchoalveolar lavage (BAL) on 30 patients with untreated pulmonary tuberculosis and assessed the type of cellular inflammatory response and cytokine production. We then correlated BAL findings and cytokine production with clinical findings. We also performed BAL on a subset of patients to examine changes in cytokine production by BAL cells over time. We found that at presentation patients with less clinically and radiographically advanced TB (smear-negative, noncavitary disease) had a local immune response characterized by a predominance of lymphocytes. Furthermore, BAL cells from these patients secreted interferon (IFNgamma), and not Interleukin-4, suggesting a Th 1-type lymphocytic response. In patients with smear-positive and/or cavitary disease, macrophages or polymorphonuclear leukocytes were the predominant BAL cell type, but with treatment and clinical improvement these patients went on to recruit IFNgamma producing cells to the lung. We conclude that the type of cellular immune response that occurs locally in the lung may affect presentation and outcome in pulmonary TB, and an understanding of the development of this response may lead to insights into pathogenesis and novel therapies for TB.

AIDS-Related Opportunistic Infections↗
PubMed1998

Transbronchial needle aspiration (TBNA) in patients infected with HIV.

Transbronchial needle aspiration (TBNA) of intrathoracic lymph nodes has been shown to be useful in the diagnosis and staging of bronchogenic carcinoma. With the exception of sarcoidosis, the usefulness of TBNA has not been widely investigated in other clinical settings. We investigated the utility of TBNA with a 19-gauge histology needle in HIV-infected patients with mediastinal and hilar adenopathy at Bellevue Hospital Center. We performed 44 procedures in 41 patients. Adequate lymph node sampling was obtained in 35 of 44 (80%), and diagnostic material was obtained in 23 of 44 (52%) procedures. TBNA was the exclusive means of diagnosis in 13 of 41 (32%) patients. Of the 44 procedures, 23 (52%) were performed in patients with mycobacterial disease, with TBNA providing the diagnosis in 20 of 23 (87%). In these patients, positive TBNA specimens included smears of aspirated materials for acid-fast bacilli in 11, mycobacterial culture in 14, and histology in 15. In other diseases, TBNA diagnosed sarcoidosis with noncaseating granulomata in 2 of 4 patients and non-small cell lung cancer in 1 of 2 patients. TBNA was not helpful in other diseases including Pneumocystis carinii pneumonia, infection with Cryptococcus or Nocardia, bacterial pneumonia, viral pneumonia, and Kaposi's sarcoma. No pulmonary diagnosis was established in five patients. No complications of TBNA occurred. We conclude that TBNA through the flexible bronchoscope is safe and effective in the diagnosis of intrathoracic adenopathy in HIV-infected patients, and is particularly efficacious in the diagnosis of mycobacterial disease. Furthermore, TBNA may provide the only diagnostic specimen in almost one-third of HIV-infected patients, thereby sparing these patients more invasive procedures such as mediastinoscopy.

AIDS-Related Opportunistic Infections↗
PubMed1998

Early inhibition of mycobacterial growth by human alveolar macrophages is not due to nitric oxide.

Phagocytic cells provide the first line of defense against mycobacteria. We examined the relative mycobacteriostatic contributions of normal human alveolar macrophages (HAM), peripheral blood monocytes (PBM), and polymorphonuclear leukocytes (PMN) in the early time period after infection with mycobacteria (48 h). Cells were infected with Mycobacterium bovis (BCG) or M. tuberculosis H37Ra and their ability to inhibit growth was determined by mycobacterial incorporation of [3H]uracil. HAM inhibited the growth of both mycobacteria (44.2 +/- 7.9 and 37.6 +/- 10.5% inhibition, respectively). Two populations of HAM donors were subsequently defined: inhibitors and noninhibitors. The ability to inhibit growth of H37Ra correlated with that of BCG. In contrast to HAM, PBM and PMN did not inhibit mycobacterial growth. Because nitric oxide (NO) has been proposed to mediate growth inhibition in murine models, we examined whether NO was responsible for the early growth inhibition of mycobacteria by HAM. As expected, in murine peritoneal macrophages (MPM) IFN-gamma (2,500 U/ml) enhanced growth inhibition of BCG; the effect was abolished by the nitric oxide synthase (NOS) inhibitor NMMA. In contrast, IFN-gamma failed to enhance growth inhibition by HAM or PBM and NMMA had no effect. MPM expressed inducible nitric oxide synthase (NOS2) mRNA in response to LPS and IFN-gamma and produced NO. Neither NOS2 mRNA nor NO could be detected in HAM stimulated with LPS and IFN-gamma or mycobacteria. These data demonstrate that HAM, but not PBM or PMN, have NO-independent mycobacteriostatic activity in the early time period after infection with mycobacteria.

Animals↗
PubMed1998

Time to detection of Mycobacterium tuberculosis in sputum culture correlates with outcome in patients receiving treatment for pulmonary tuberculosis.

STUDY OBJECTIVE: The purpose of this study was to determine whether the time to detection (TTD) of Mycobacterium tuberculosis in sputum culture correlates with the response to antituberculous treatment in patients with pulmonary tuberculosis. STUDY DESIGN: Twenty-six consecutive patients were studied who had active pulmonary tuberculosis and sufficient sputum cultures and clinical follow-up to allow adequate assessment. RESULTS: Following initiation of antituberculous therapy, 13 patients (group 1, responders) had a complete response to treatment, and the TTD of M tuberculosis using the mycobacterial growth indicator tube increased steadily. The remaining 13 patients (group 2, nonresponders) had persistent evidence of active disease and demonstrated little or no increase in the TTD with treatment unless an additional therapeutic intervention was implemented (surgery, improved compliance with medications, or a change in medications). The presence of HIV infection, intravenous drug use, multidrug resistance, treatment with second-line therapy, extensive radiographic involvement, and cavitary disease were associated with a delayed increase in the TTD. CONCLUSIONS: The TTD was superior to clinical, radiographic, or conventional bacteriologic evaluation in determining treatment outcome. The TTD closely correlates with the overall response to treatment for pulmonary tuberculosis and may represent a useful adjunct to predict outcome in these patients.

Adult↗
PubMed1998

Valvular endocarditis due to Mycobacterium tuberculosis.

Granulomas due to Mycobacterium tuberculosis are rarely observed in valvular structures. When observed, they are associated with disseminated tuberculosis in immunocompromised patients. We report the first case of tuberculous valvular endocarditis isolated in an immunocompetent patient. The patient had severe mitral valve regurgitation due to a perforation of the anterior leaflet of the mitral valve. M. tuberculosis was cultured from the vegetations and no other tuberculous foci were identified. This case exemplifies the protean manifestations of M. tuberculosis infections.

Endocarditis, Bacterial↗
PubMed1997

Angular and fibrous particles in lung are markers of job categories.

INTRODUCTION: The lung concentration of angular and fibrous particles has been measured when cases are stratified into their job categories; 21 miners (metallic mines such as gold, zinc and copper), 18 iron foundrymen, 22 non-iron foundrymen, four welders, three sand-blast workers, four construction workers, three technicians and professionals, seven workers in other trades excluding welding. Twelve asbestos miners representing a positive exposure to asbestos and 20 people representing a background population were added to the previous groups. MATERIAL AND METHODS: Particles, both angular and fibrous, were extracted from lung parenchyma by a bleach digestion method, mounted on copper microscopic grids by a carbon replica technique and analyzed by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). Quartz concentration was also determined by X-ray diffraction (XRD) on a silver membrane filter after the extraction from the lung parenchyma. RESULTS: (1) The highest concentrations of quartz were found in mines (metallic mines), iron foundrymen and sand-blast workers. Notable amounts quartz were found in welders and professionals. (2) The highest concentrations of short fibres were found in non-iron foundrymen, asbestos miners and construction workers. (3) The highest concentrations of long fibres were found in non-iron foundry men and asbestos miners. (4) The highest concentrations of ferruginous bodies were found in non-iron foundrymen and asbestos miners. (5) The non-iron foundrymen were exposed to ceramic fibres and asbestos fibres. CONCLUSION: The results of the study may not be representative of the broad spectrum of workers in the industrial activities in which they have been involved. However, the detailed composition of the retained particles of our workers is explained both qualitatively and quantitatively by their work histories. Finally, the broad range of particle types identified in the lungs of these workers illustrate the complexity or trying to determine disease origins in these occupational settings.

Biological Availability↗