Recent methodological developments allow expression measurement of many genes simultaneously, thereby revealing patterns of gene expression that can be related to phenotype. We hypothesized that through the use of such methods we could identify patterns of gene expression associated with the malignant phenotype in human bronchial epithelial cells (BEC). To test this hypothesis, a recently developed quantitative reverse transcriptase polymerase chain reaction method was used to assess simultaneously expression of 15 genes mechanistically associated with cell-cycle control (c-myc, E2F-1, p21, rb, PCNA, cyclin D2, cyclin D3, cyclin E, cdc2, CDK2, CDK4, mad, max p21, max p22, and p53) in normal cell cultures from five individuals and in nine different malignant BEC lines. Relative to the mean expression levels in cultured normal cell populations, expression of c-myc, E2F-1, PCNA, cyclin E, and CDK4 messenger RNA (mRNA) were significantly increased and expression of p21 and p53 mRNA were significantly decreased in one or two, but not all three subtypes (squamous, adenocarcinoma and small cell) of carcinoma cell lines evaluated. No single cell-cycle control gene discriminated all three subtypes from normal cell populations. In contrast, the gene expression index c-myc x E2F-1/p21 separated all carcinoma cell lines from all normal cell populations initially evaluated. This malignancy index was validated in an additional three cultured normal BEC and three carcinoma cell lines, as well as three pairs of matched primary normal bronchial epithelial and primary bronchogenic carcinoma samples, and three pairs of matched primary normal lung parenchyma and primary bronchogenic carcinoma tissue. Again, the c-myc x E2F-1/ p21 index successfully discriminated all cultured and primary normal from malignant samples and thereby had a predictive value of 1 (no false positives and no false negatives). We hypothesize that because of functional mutations in cell-cycle regulatory genes (e.g., p53 and/or rb), cells lose the ability to maintain a pattern of gene expression mechanistically associated with normal, division-limited homeostatic equilibrium. Because the c-myc x E2F-1/p21 gene expression index has high specificity for malignant tissue, it will allow confirmation that there is a significant amount of tumor tissue present in small (e.g., fine-needle) biopsy specimens prior to evaluating them for expression of other genes, such as those involved in chemoresistance or radioresistance. In addition, the goal of most gene therapy efforts is to alter levels of gene expression quantitatively. This index and others derived in a similar manner may better define potential gene therapy targets as well as response of targeted genes to therapy.
Systemic inflammatory response conditions are associated with capillary leak and haemodynamic compromise. Fluid resuscitation to reverse the ensuing hypovolaemia is, however, complicated by the decreased endothelium reflection coefficient to albumin and other colloids. We developed PEG-Alb (albumin covalently linked to polyethylene glycol) as a potential resuscitative agent. PEG was covalently linked to human albumin at multiple sites on the protein. The modified protein was heterogeneous when examined by SDS/PAGE, size-exclusion chromatography and SELDI-TOF MS (surface-enhanced laser-desorption ionization-time of flight MS). Based on size-exclusion chromatography and osmotic pressure data, the effective volume of PEG-Alb is increased 13- to 16-fold compared with unmodified albumin. In an LPS (lipopolysaccharide) model of shock, rats treated with PEG-Alb showed better blood pressure, lower Hct (haematocrit) consistent with haemodilution and less lung injury than rats treated with unmodified albumin or saline. In a CLP (caecal ligation and puncture) model of sepsis, PEG-Alb was more effective than albumin or saline in maintaining blood pressure and in decreasing Hct. When fluorescein-labelled PEG-Alb and Texas Red-labelled albumin were administered to rats with LPS- or CLP-induced shock, PEG-Alb was retained within blood vessels, whereas albumin extravasates into the interstitial space. Based on these data, PEG-Alb appears to be retained within blood vessels in models of capillary leak. PEG-Alb may ultimately be effective in the clinical treatment of shock associated with capillary leak.
Morphological analysis of cytologic samples obtained by fine-needle aspirate (FNA) or bronchoscopy is an important method for diagnosing bronchogenic carcinoma. However, this approach has only about 65 to 80% diagnostic sensitivity. Based on previous studies, the c-myc x E2F-1/p21WAF1/CIP1 (p21 hereafter) gene expression index is highly sensitive and specific for distinguishing normal from malignant bronchial epithelial tissues. In an effort to improve sensitivity of diagnosing lung cancer in cytologic specimens, we used
Rhodococcus equi pneumonia with systemic dissemination is being reported increasingly in immunocompromised patients. This is the first case report of disseminated R equi infection with biopsy documented involvement of the large intestine. The patient was a 46 year old male with AIDS who was diagnosed with cavitating pneumonia involving the left lower lobe. R equi was isolated in culture from the blood and lung biopsies. Subsequently, the patient developed anaemia, diarrhoea, and occult blood in the stool. Colonoscopy revealed several colonic polyps. Histological examination of the colon biopsies showed extensive submucosal histiocytic infiltration with numerous Gram positive coccobacilli and PAS positive material in the histiocytes. Electron microscopy showed variably shaped intrahistiocytic organisms which were morphologically consistent with R equi in the specimen. Disseminated R equi infection may involve the lower gastrointestinal tract and produce inflammatory polyps with foamy macrophages which histologically resemble those seen in Whipple's disease and Mycobacterium aviumintracellulare infection. (J Clin Pathol 1999;52:68-71)
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