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Small Cell Lung Cancer (SCLC), a clinically aggressive cancer, accounts for approximately 25% of primary lung cancers. We carried out suppression subtractive hybridization (SSH), a PCR-based method for cDNA subtraction, between the human classic, NCI-H69 and variant, more aggressive NCI-N417 SCLC cell lines to isolate and characterize variable expression of genes, which may be responsible for differential degree of tumorigenicity of SCLC. Using NCI-N417 as a tester, we obtained 28 differentially expressed cDNA clones from a total of 60 arbitrarily picked clones. Among the 28 cDNA clones, 4 were unknown genes, 2 were fatty acid binding protein (FABP) with specific identification of mRNA for mammary-derived growth inhibitor (MDGI), 1 was human alpha-enolase, 4 were ribosomal proteins, 2 were structural genes, vimentin and moesin (membrane-organizing extension spike protein), and 9 were homologous with murine leukemia viruses, whereas 2 others had enhanced expression in NCI-H69 and A549 cell lines, and 4 were cell surface proteins and murine type C retrovirus. Expression of FABP/MDGI was significantly high in NCI-H417, which may influence mitosis and cell growth as implicated in other tissues, contrary to the conclusion drawn for the role of MDGI in human breast cancer. Higher expression of ribosomal proteins in NCI-N417 compared to NCI-H69 may have a role in differential tumorigenicity and metastatic ability. Further, we obtained 14 differentially expressed cDNA clones by reversing the tester and driver, using NCI-H69 as a tester. Of these 14 differential cDNAs, 5 were unknown genes, 2 were specific for keratins, others had similarities with protease inhibitor, human BAC clone, Alu RNA binding protein, and tumor expression-enhanced gene. Characterization of these differentially expressed cDNA clones will provide useful information in understanding of the genes responsible for differential tumorigenicity of SCLC., (Copyright 2000 Academic Press.)

To evaluate lung development at the level of gene expression, a comparison was made between normal and hypoplastic murine fetal lungs by using the mRNA differential display technique. We focused on altered gene expressions at gestational day (Gd) 19 in normal and hypoplastic murine lungs. Hypoplastic fetal lungs were created by gavaging pregnant mice at Gd8 with 25 mg of nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether) [1]. Normal as well as gavaged mice were euthanized by an overdose of halothane at Gd19, and fetuses were removed by laparotomy. Lungs were excised and total RNA was extracted from normal and hypoplastic fetal lungs. Differential display technique was carried out using the RNAimage kit (GenHunter Corp., TN). Each reverse transcription and polymerase chain reaction (RT-PCR) was performed using one specific anchor primer H-T11M (5'HindIII-T11A/C/G3') and one arbitrary primer. We have used a total of 3 different anchor primers and 24 arbitrary primers for each sample. There were 20 differentially expressed cDNA clones, either induced, inhibited, enhanced, or reduced in hypoplastic fetal lungs as compared to normal. Of these, one clone (NL2) with reduced expression in Gd19 hypoplastic lungs had 100% homology with mouse nucleosome assembly protein I gene. Another clone (NT5) with induced expression in hypoplastic lungs is an unknown gene. Further, analyses of Northern blots of lungs from various gestational ages showed that the expression of NT5 was induced in hypoplastic lungs at Gd18, whereas in normal lungs it was first expressed at the neonatal stage and was increasingly expressed into adulthood. There is a single hybridized band, approximately 400 bp long for NT5 message. Dexamethasone induced expression of NT5 in normal Gd14 pseudoglandular lungs cultured for 7 days; however, different growth factors did not. Northern blot hybridization of multiple adult mice tissues showed NT5 expression in the lung, intestine, and spleen. The thyromimetic action of nitrofen and the interactive functional pathways of dexamethasone with T3 are known. Therefore, we suggest that the isolation and characterization of NT5 may provide valuable information on the regulation of lung development.

In pentobarbital-anesthetized dogs, oxygen delivery (DO2) was measured by thermodilution cardiac output and cooximeter determined oxygen content, while oxygen consumption (VO2) was measured independently by spirometry. Oxygen delivery was decreased by isovolemic dilutional anemia, breathing hypoxic gas mixtures, or cardiac tamponade to reduce cardiac output. Baseline VO2 (cc/kg/min) for the three groups was 5.9 +/- 0.7 (anemia), 5.4 +/- 0.4 (hypoxia), and 5.6 +/- 0.1 (low C.O.) (NS). A critical level of oxygen delivery (DO2crit) was found at 9-10 cc/kg/min (anemia), 10-11 cc/kg/min (hypoxia), and 9-10 cc/kg/min (low C.O.) (NS.). Below this level, VO2 fell (became supply dependent) and lactic acidosis occurred, regardless of the mechanism of impaired oxygen delivery.

This experiment investigated the relationship between oxygen consumption and oxygen delivery (cardiac output X arterial oxygen content) in an acute canine model. Previous studies investigating this relationship have largely utilized methods in which oxygen consumption and oxygen delivery were each calculated using the same measured variables resulting in mathematical coupling of variables. In this study, oxygen consumption was measured directly by closed-circuit spirometry. Oxygen delivery was independently controlled using right atrial bypass. These techniques assured that the values for oxygen consumption and oxygen delivery were derived entirely independently. In our study using 11 dogs, we found that oxygen consumption was constant and independent of oxygen delivery at oxygen delivery levels greater than 8.0 cc/kg/min (normal canine oxygen delivery 20-25 cc/kg/min). Oxygen consumption was linearly related to oxygen delivery at oxygen delivery levels less than or equal to 8.0 cc/kg/min. Below this critical level of oxygen delivery, animals were more acidotic and hypotensive than at higher delivery levels.