Faculty Bibliography

Reported estimates of ras mutation prevalence in lung adenocarcinoma of 15-24% may be underestimates because of the insensitivity of the assays used. We have devised a rapid, non-radioactive assay for ras mutations, which detects 1 mutant allele/10(3) normal alleles and have used it to study DNA isolated from 53 lung tumor samples (including 28 adenocarcinomas) previously analyzed by PCR/allele specific oligonucleotide hybridization, which is less sensitive. We detected mutations in 13 of 28 samples, including 7 not detected by PCR/allele specific oligonucleotide hybridization. We also found ras mutations in 14 of 25 previously unstudied samples (56%). Our results indicate that the prevalence of K-ras codon 12 mutations in lung adenocarcinoma is higher than previously reported; thus, ras mutations may be more clinically useful as molecular markers for lung cancer than has been appreciated

BACKGROUND: Lung cancer is the leading cause of cancer deaths in the United States. A long-standing goal of cancer researchers has been to develop tests that would facilitate earlier diagnosis and treatment of lung cancer and thereby decrease mortality from this disease. Because cancer results from the accumulation of a variety of genetic events (e.g., mutations, rearrangements, and deletions) in genes controlling cell growth and differentiation, these changes might serve as diagnostically useful molecular markers. Activation of the K-ras oncogene by point mutations in codon 12, which occurs in many cases of lung adenocarcinoma, may serve as one such clinically useful molecular marker. For detection of K-ras point mutations in bronchoalveolar lavage fluid, in which small numbers of malignant cells are mixed with a population of predominantly genetically normal cells, the sensitivity of commonly used assays for ras mutations risks false-negative results. PURPOSE: By applying a highly sensitive assay, we investigated whether detection of K-ras codon 12 mutations in samples of bronchoalveolar lavage fluid could be clinically useful in diagnosing lung cancer. METHODS: We developed a highly sensitive assay for detecting K-ras codon 12 mutations based on an enriched polymerase chain reaction (PCR) technique. This technique was applied to 87 specimens of bronchoalveolar lavage fluid specimens that were obtained from 86 patients, and associated tumor biopsy specimens obtained from 35 of these patients who underwent diagnostic bronchoscopy for clinically suspected lung cancer. Statistical comparisons were performed by using the two-tailed Fisher's exact test [corrected]. RESULTS: Of 52 patients with confirmed lung cancer, samples of bronchoalveolar lavage fluid from 16 patients contained K-ras codon 12 mutations, including 14 (56%) of 25 patients with lung adenocarcinomas, one (33%) of three with bronchoalveolar carcinomas, one (20%) of five with large-cell carcinomas, and none of the 14 with squamous cell carcinomas. Mutations were detected in four additional cases in which cancer was suspected but had not been histologically confirmed. Tissue samples from 35 of the patients all yielded the identical K-ras codon 12 genotype found in the corresponding samples of bronchoalveolar lavage fluid. No mutation was found in any sample from 30 patients with diagnoses other than non-small-cell lung cancer. Thus, for those cases in which tissue was available and tested, the sensitivity and specificity of detecting K-ras mutations in bronchoalveolar lavage fluid for diagnosing K-ras mutation-positive lung cancer were both 100%. For nine patients, K-ras mutations were detected in bronchoalveolar lavage fluid obtained during otherwise nondiagnostic bronchoscopies. CONCLUSIONS: Our data demonstrate that sensitive detection of K-ras codon 12 mutations can serve as an important adjunct to cytology in the diagnosis of lung cancer. IMPLICATIONS: Detection of these mutations could lead to earlier cancer diagnosis and less need for invasive diagnostic procedures

Despite the importance of tuberculosis as the leading cause of death due to infectious disease in the world, it has only been recently that an understanding of the human host response in this infection has begun to emerge. The key components of this response are cytokines and components of cellular immunity, predominantly T-lymphocytes and macrophages. Though the relationships among the components of the immune response are complex, it seems likely that in response to mycobacterial infection associated with active disease, cytokines such as TNF-alpha and IL-1 beta are produced; these cytokines serve to recruit more lymphocytes, generally of the T(H) (T helper) phenotype, which then produces substances such as the macrophage activating factor interferon-gamma. Macrophages activated by IFN-gamma ar thus stimulating to enhance intracellular killing of mycobacteria. The role of other cytokines, such as IL-6 and IL-8, both of which are induced by M. tuberculosis or its cell was components, is less clear. Further elucidation of the human host response to tuberculosis should help in the development of new vaccines and treatment strategies

BACKGROUND: The monocyte-derived cytokine, tumor necrosis factor alpha (TNF alpha), is essential for host immunity, but overproduction of this cytokine may have serious pathologic consequences. Excess TNF alpha produced in pulmonary tuberculosis may cause fevers, weakness, night sweats, necrosis, and progressive weight loss. Thalidomide (alpha-N-phthalimidoglutarimide) has recently been shown to suppress TNF alpha production by human monocytes in vitro and to reduce serum TNF alpha in leprosy patients. We have therefore conducted a two-part placebo-controlled pilot study of thalidomide in patients with active tuberculosis to determine its effects on clinical response, immune reactivity, TNF alpha levels, and weight. MATERIALS AND METHODS: 30 male patients with active tuberculosis, either human immunodeficiency virus type 1 positive (HIV-1+) or HIV-1-, received thalidomide or placebo for single or multiple 14 day cycles. Toxicity of the study drug, delayed type hypersensitivity (DTH), cytokine production, and weight gain were evaluated. RESULTS: Thalidomide treatment was well tolerated, without serious adverse events. The drug did not adversely affect the DTH response to purified protein derivative (PPD), total leukocyte, or differential cell counts. TNF alpha production was significantly reduced during thalidomide treatment while interferon-gamma (IFN gamma) production was enhanced. Daily administration of thalidomide resulted in a significant enhancement of weight gain. CONCLUSIONS: The results indicate that thalidomide is well tolerated by patients receiving anti-tuberculosis therapy. Thalidomide treatment reduces TNF alpha production both in vivo and in vitro and is associated with an accelerated weight gain during the study period

The precise roles of fiberoptic bronchoscopy (FOB) and computed tomography (CT) of the chest in the evaluation of patients presenting with hemoptysis have not been clearly defined. On the assumption that both procedures would likely provide unique and complementary information, a prospective study with blinded interpreters using a modified high-resolution CT technique (HRCT) and FOB was designed to evaluate 57 consecutive patients admitted to Bellevue Hospital with hemoptysis. Etiologies included bronchiectasis (25 percent), tuberculosis (16 percent), lung cancer (12 percent), aspergilloma (12 percent), and bronchitis (5 percent): in an additional 5 percent of cases, hemoptysis proved to be due miscellaneous causes, while in 19 percent hemoptysis proved to be cryptogenic. Patients with lung cancer all were at least 50 years old, smoked an average of 78 pack-years, and had less severe hemoptysis but of longer duration. All had conditions diagnosed both by HRCT and FOB. High-resolution CT proved of particular value in diagnosing bronchiectasis and aspergillomas, while FOB was diagnostic of bronchitis and mucosal lesions such as Kaposi's sarcoma. Fiberoptic bronchoscopy localized bleeding in only 51 percent of cases. The high sensitivity of CT in identifying both the intraluminal and extraluminal extent of central lung cancers in conjunction with its value in diagnosing bronchiectasis suggest that CT should be obtained prior to bronchoscopy in all patients presenting with hemoptysis

We recently observed a striking increase in multidrug-resistant tuberculosis (MDR-TB) among patients admitted to the Chest Service at Bellevue Hospital Center in New York. We reviewed the laboratory susceptibility test results of 4,681 tuberculosis (TB) cases over the past 20 years, Combined resistance to isoniazid and rifampin increased from 2.5 percent in 1971 to 16 percent in 1991 with higher rates noted for individual drugs. We reviewed the medical records of 100 patients with drug-resistant TB, finding that these individuals were predominantly less than 40 years of age, minority, male, jobless, undomiciled, with a high percentage of drug abuse and human immunodeficiency virus infection. We conclude that the epidemics of AIDS and TB are complicated by a third epidemic of MDR-TB. This third epidemic requires urgent attention to achieve more rapid diagnosis, to develop new therapeutic regimens, and to address the social and hospital environment ot care for these individuals

Human immunodeficiency virus infection changes the clinical presentation of tuberculosis infection with atypical radiographs and more common extra-pulmonary involvement. We retrospectively studied pleural tuberculosis in HIV-positive patients over a 5-year period. We identified 70 patients with pleural tuberculosis by positive Mycobacterium tuberculosis cultures of pleural fluid and/or pleural tissue, including 43 HIV-positive and 27 HIV-negative patients. The HIV-positive patients were significantly younger (mean age, 38 +/- 1 years in HIV-positive vs 52 +/- 3 years in HIV-negative patients, p < 0.05). There were more intravenous drug abusers in the HIV-positive group (74 vs 30 percent, p < 0.01). The HIV-positive group had significantly fewer positive tuberculin skin tests (41 percent vs 76 percent, p < 0.03). Both groups had similar pleural fluid cellularity and pleural biopsy histologic conditions, but the HIV-positive patients demonstrated significantly more acid-fast bacteria identifiable in pleural tissue (69 percent vs 21 percent, p < 0.01), and a higher incidence of positive M tuberculosis cultures of sputum (53 percent vs 23 percent, p = 0.02). Pleural tuberculosis in HIV-positive patients presented more often as a manifestation of a greater burden of microorganisms and impaired host response

OBJECTIVE: To evaluate the clinical utility of the polymerase chain reaction (PCR) in the diagnosis of infections due to Mycobacterium tuberculosis. DESIGN: Clinical specimens were assayed by PCR for the presence of the insertion element IS6110, a DNA sequence unique to the M tuberculosis complex of organisms. The PCR results were then correlated with acid-fast bacilli (AFB) smears, cultures, pathology, and clinical histories. SETTING: Bellevue Hospital, a large municipal teaching hospital. PATIENTS: Inpatients on the Bellevue Chest Service. MEASUREMENTS AND RESULTS: Sixty-five patients were evaluated. The PCR for M tuberculosis was positive in 37 patients and negative in 28. When correlated with smears, cultures, pathology, and clinical history, the sensitivity of PCR for a diagnosis of active tuberculosis (TB) was 100 percent. However, the specificity for a diagnosis of active TB was only 70 percent, as the PCR assay was positive in a number of patients with only prior, treated TB, or asymptomatic tuberculous infection. For a diagnosis of any TB infection (active, treated, or asymptomatic), sensitivity of PCR was 87.5 percent and specificity was 90 percent. CONCLUSIONS: The PCR assay for TB is extremely sensitive, but it lacks specificity for a diagnosis of active TB. Its role in clinical practice will likely be limited to well-defined situations, such as HIV-positive patients with intrathoracic adenopathy, and it may be most useful in excluding active TB from consideration in selected patients. Given the cost of the assay and the labor intensity it requires, it should not be part of the routine initial evaluation of patients with suspected pulmonary TB