Fiberoptic bronchoscopy and pleural effusion of unknown origin

We reviewed our experience with fiberoptic bronchoscopy (FOB) in patients with pleural effusion of unknown origin. Seventy patients underwent FOB for the investigation of pleural effusion between 1978 and 1983. Those with a second reason for FOB, a mass on chest roentgenogram, or lobar atelectasis were excluded. Forty five patients remained: 28 patients with unexplained pleural effusion after pleural fluid analysis and pleural biopsy (UPE), and 17 patients with malignant pleural fluid cytology and/or pleural biopsy but no known primary tumor (MPE). In the UPE group, only one FOB demonstrated malignancy, despite a final diagnosis of tumor in seven. No other specific diagnoses were made by FOB in this group. In the MPE group, FOB demonstrated bronchogenic carcinoma in two; ultimately, five patients were found to have a bronchogenic neoplasm. Although pleural effusion of unknown origin is frequently caused by bronchogenic carcinoma, FOB in the absence of other indications for this procedure is rarely diagnostic and should not be routinely employed.     

Characterization of revertants of the CHO EM9 mutant arising during DNA transfection

We have studied reversion in DNA repair deficient EM9 cells, by selection for ethylmethanesulfonate (EMS) resistance. EM9 is a mutant CHO cell line that is hypersensitive to killing by EMS and X-rays and deficient in DNA single-strand break (SSB) repair. EM9 cells were transfected with DNA from a cosmid library, and transfectants resistant to EMS were isolated. Four revertant lines were obtained, which varied in their sensitivity to killing by EMS, ionizing radiation and other genotoxic agents. When the cell lines were analyzed for resistance to killing by chlorodeoxyuridine (CldUrd) or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a different relative ranking among the cell lines was observed. The recently cloned human XRCC1 gene is capable of correcting the deficiencies of the EM9 cell line. Using the human XRCC1 cDNA (pXR1-30) as a probe, we determined that the resistant-transfectant cell lines contained only the endogenous hamster XRCC1 gene, implying that a hamster XRCC1 gene was altered during the transfection/selection procedure and was responsible for the EMS resistance. In these cells the levels of XRCC1 mRNA corresponded roughly to the degrees of resistance of the reverted cell lines to killing by EMS or X-rays. The degree of increased resistance to killing by EMS or X-rays also roughly correlated with increased SSB repair. These results suggest that increased cellular levels of the endogenous XRCC1 gene mRNA may largely, though not completely, explain the phenotypes of revertant, EMS-resistant EM9 cell lines.     

AK37: the first pyridoacridine described capable of stabilizing the topoisomerase I cleavable complex

Pyridoacridines are marine natural products that contain planar structures. Almost all are cytotoxic and capable of DNA intercalation. Several pyridoacridines have demonstrated anti-cancer activity, being able to generate reactive oxygen species or to inhibit topoisomerase (Topo) II. Synthetic pyridoacridines were characterized and compared to other pyridoacridines as well as the Topo-inhibiting drugs (etoposide, 9-aminocamptothecin and wakayin) in a series of in vitro enzyme systems. We found AK37 was able to stabilize a DNA-Topo I cleavable complex, but not a DNA-Topo II cleavable complex. To our knowledge, this is the first report of a DNA-Topo I cleavable complex stabilizing pyridoacridine. Structure comparison studies demonstrated that this activity was lost when an extra 'F' ring was added, but activity was not affected when the 'D' ring was removed. AK37 inhibited the catalytic activity of both human Topo I and II.     

Interleukin-1 family expression in human breast cancer: interleukin-1 receptor antagonist

We hypothesize that interleukin-1 alpha, beta, and receptor antagonist (IL-1 alpha, IL-1 beta, and IL-1 ra, respectively) are present and tumor cell associated in human breast cancer (HBC). We believe the levels of these cytokines in breast tumor homogenates relate to other known prognosticators of patient survival (i.e., estrogen receptor [ER] status). Our results demonstrated that, immunohistochemically, tumor cells express IL-1 alpha, IL-1 beta, and IL-1 ra in most specimens tested. In breast tissue homogenates, IL-1 alpha levels correlated inversely with ER levels (p < 0.06), whereas IL-1 ra levels correlated directly with both ER levels (p < 0.009) and IL-1 beta levels (p < 0.06). When analyzing cytokine levels for the ER (-) versus ER (+) patient groups, we found that in many instances these groups showed a different cytokine profile. These studies suggest that the IL-1 family of cytokines may be important in regulating protumorigenic activities within the HBC tumor microenvironment.     

Immunochemical detection of human blood in feces.

Current methods for testing stool samples for hemoglobin utilize peroxidase oxidation of chemical indicators such as guaiac or benzidine. These tests have frequent false-positive and false-negative results, complicating random screening for occult gastrointestinal bleeding. The authors have developed an immunochemical test for human blood in feces using goat antibodies to hemoglobin. When employed in radial immunoassay the test is uncomplicated by cross-reaction with common human foods or other nonhemorrhagic fecal fecal constitutents. The lower limit of sensitivity for hemoglobin in stool samples is 10 mg/dl, compared with a commonly reported threshold of 100 mg/dl for peroxidase tests. The test accurately detects hemoglobin in mixtures of human blood and feces. Immunochemical identification of human blood in stool offers improved detection of lower gastrointestinal bleeding.     

The interleukin-1 family of cytokines and receptors in human breast cancer: implications for tumor progression

We have previously described the expression of interleukin cytokines (IL)-1alpha, IL-1beta, and IL-1 receptor antagonist (IL-1ra) in human breast cancer (HBC) tissue. Based on our previous studies, we hypothesize that the IL-1 family of cytokines, antagonists (IL-1ra) and receptors (IL-1RI and IL-1RII) are present within the human breast cancer (HBC) tumor microenvironment and that the IL-1 network of cytokines and receptors within the tumor microenvironment can control tumor cell subpopulation expression of other protumorigenic cytokines such as the angiogenic/growth factor, interleukin-8 (IL-8). To test this hypothesis we characterized the in vivo expression of the IL-1 network in HBC tissues and homogenates by immunohistochemistry (IHC) and ELISA. Additionally, we examined IL-1R expression in HBC cell lines in vitro and in a murine xenograft model by IHC. Finally, we determined the ability of IL-1 to induce IL-8 expression in in vitro using HBC cell lines. We observed that not only are the IL-1 cytokines present in HBC tissue and homogenates, but that IL-1Rs and IL-8 are also present in the HBC tumor microenvironment. Additionally, expression levels for some members of the IL-1/IL-8 network of cytokines correlated with the prognostic indicators, ER/PR. Using HBC cell lines, we observed that HBC cell lines express IL-1Rs in vitro and in the xenograft model. Furthermore, in vitro, HBC cell lines show a spectrum of responsiveness to IL-1 as measured by expression the proangiogenic/mitogenic cytokine IL-8. Our data clearly demonstrate the presence and distribution of IL-1 cytokines and receptors in HBC and suggests that the local expression of IL-1 results in the activation of a population of cells within the HBC tumor microenvironment. This activation of the IL-1/IL-1R cytokine family via autocrine and/or paracrine mechanisms leads to a cascade of secondary protumorigenic cytokines. These secondary signals induce the expression of numerous protumorigenic activities such as the expression of IL-8, and subsequently contribute to angiogenesis, tumor proliferation, and tumor invasion.     

Transfectant CHO cells expressing O6-alkylguanine-DNA-alkyltransferase display increased resistance to DNA damage other than O6-guanine alkylation

BCNU [1,3-bis(2-chloroethyl)-1-nitrosourea, Carmustine] is anitrosourea that crosslinks DNA and is useful in cancer chemotherapy.Tumor cells resistant to BCNU produce high levels of O⁶-alkylguanine-DNA-alkltransferase(AT), a protein that removes the O⁶-guanine adduct formed byBCNU prior to crosslinking. By the transfection of a human cosmidlibrary into the Chinese hamster ovary cell line AA8, severaltransgenic cell lines which express the AT gene have been constructed.These ‘BR’ cells were isolated on the basis of theirresistance to G-418 and BCNU. Like human mer⁺ strains, BR cells(relative to the parental AA8 cells) are {small tilde}500 timesmore resistant to the cytotoxic effects of 80 µM BCNU.Treatment with exogenous O⁶-methylguanine (O⁶MG), which depletescellular AT, abolishes their BCNU resistance. Also consistentwith the mer⁺ phenotype, BR cells are resistant to the mutagenicand killing activity of N-methyl-N'-nitro-N-nitrosoguanidine(MNNG). Treatment with exogenous O⁶MG, while reversing the resistanceto MNNG mutation, does not reverse the resistance to MNNG killing.Unexpectedly, BR cells also exhibit resistance to killing bydimethylsulfate (DMS). The BR cells are not, however, detectablyresistant to UV light. These results suggest that AT activityin mammalian cells is dosely linked to the activity of otherDNA repair pathways.     

Effect of magnification on locating the MB2 canal in maxillary molars

The purpose of this study was to determine if the surgical operating microscope and/or dental loupes could enhance the practitioner's ability to locate the second mesiobuccal canal (MB2) canal of maxillary molars in an in vivo, clinical setting. The participating endodontists documented 312 cases of root canal therapy on maxillary first and second molars. Participants that used the microscope or dental loupes located the MB2 canal with a frequency of 57.4% and 55.3%, respectively. Those using no magnification located the MB2 canal with a frequency of 18.2%. When no magnification was used, significantly fewer MB2 canals were located based by Chi-square analysis at p < 0.01. There was no significant difference between the use of the microscope and dental loupes in the frequency of locating the MB2 canal. When the maxillary first molars were considered separately, the frequency of MB2 canal detection for the microscope, dental loupes, and no magnification groups was 71.1%, 62.5%, and 17.2%, respectively. The results of this study show that the use of magnification in combined groups leads to a MB2 detection rate approximately three times that of the nonmagnification group and that the use of no magnification results in the location of significantly fewer MB2 canals. Based on these results, more emphasis should be placed on the importance of using magnification for locating the MB2 canal.