Emphysema in young adult survivors of moderate-to-severe bronchopulmonary dysplasia.

Improved survival following extreme preterm birth complicated by bronchopulmonary dysplasia (BPD) is resulting in an increasing number of affected infants surviving to adulthood. The aim of the present pilot study was to describe the functional and structural pulmonary sequelae of moderate and severe BPD in a population of adult survivors. All babies were cared for at one institution (King Edward Memorial Hospital, Subiaco, Australia). Subjects born between 1980 and 1987 with birthweight <1,500 g and requiring supplementary oxygen at 36 weeks post-menstrual age were identified from a complete neonatal database and recruited prospectively. Local physicians were concurrently asked to refer suitable patients. Demographics, respiratory symptoms and examination results, pulmonary function tests and computed tomography images were acquired. In total, 21 subjects were studied. Of these, 12 were female, the median (range) age was 19 (17-33) yrs and 15 (71%) had persistent respiratory symptoms. The median (range) forced expiratory volume in one second (FEV(1)) z-score was -0.77 (-8.20-1.37), the forced expiratory flow at 25-75% of forced vital capacity was -1.81 (-6.00-0.75) and the diffusing capacity of the lung for carbon monoxide was -5.04 (-13.17- -1.24). Computed tomography was carried out on 19 subjects and all had abnormal findings, with emphysema being the most common, present in 84% of subjects. The extent of radiological emphysema was inversely related to the FEV(1) z-score. Young adult survivors of moderate and severe bronchopulmonary dysplasia may be left with residual functional and characteristic structural pulmonary abnormalities, most notably emphysema.

Mechanism of autocrine stimulation in hematopoietic cells producing interleukin-3 after retrovirus-mediated gene transfer.

Endogenous expression of the interleukin-3 (IL3) gene introduced with a retrovirus vector renders hematopoietic cells autonomous of exogenous growth factor. To investigate the mechanism of autocrine stimulation, 25 clones were isolated after retrovirus transduction of IL3 into 32D-cl23 or FDC-P1 cells. Medium conditioned by these autonomous IL3-producing clones supported the growth of factor-dependent 32D cells. Although there was a severalfold variation in the amount of IL3 secreted (some clones secreted barely detectable levels), the doubling time of each clone in the absence of added IL3 was identical to that of the parental cell line maximally stimulated by exogenous IL3. Concentrated monoclonal and polyclonal antibodies, both highly effective in neutralizing exogenous IL3, were assayed for ability to inhibit autocrine growth. Minimal inhibitory effects were observed only on washed autocrine clones secreting low levels of IL3. To test the activity of cytoplasmically synthesized IL3, the nucleotides encoding the signal sequence of IL3 were deleted and replaced with an in-frame ATG in the context of a consensus translation initiation sequence. Ten 32D clones expressing this restructured IL3 genome were obtained. Despite the presence of biologically active IL3 in cell lysates, all clones remained dependent on exogenous IL3, with the same dose-response as that found for 32D cells. Our data are most compatible with a mechanism whereby endogenously produced IL3 interacts with its receptor prior to surface display.

Retrovirus-mediated transfer and expression of the interleukin-3 gene in mouse hematopoietic cells result in a myeloproliferative disorder.

A high-titer, recombinant retroviral vector produced in psi 2 packaging cells has been used to introduce the murine interleukin-3 (IL-3) gene into mouse hematopoietic cells. Integration and expression of the IL-3 gene was observed in spleen foci from which could be derived factor-independent, continuously proliferating cell lines. Irradiated or genetically anemic W/Wv recipients of infected hematopoietic cells developed a myeloproliferative syndrome characterized by a marked elevation in leukocyte count, bone marrow hyperplasia, and enlargement of the liver and spleen. The syndrome reflected proliferation of one or more stem cell clones, the progeny of which were capable of repopulating secondary recipients. One animal developed the syndrome primarily by a paracrine mechanism. Endogenous IL-3 production caused amplification of hematopoietic cells but did not appear to alter the maturational or self-renewal potential of these cells.

Activation of quiescent ABL-transduced hemopoietic stem cells.

Chronic myelogenous leukemia (CML) is a hemopoietic stem cell disorder in which an activated ABL oncogene is expressed and has been shown to play an important role in disease pathogenesis. A mouse model has been established in which hemopoietic stem cells (HSCs) transduced with a retrovirus vector carrying an activated ABL oncogene can be analysed. Using this model, we now report that abl-transduced HSCs can be quiescent without causing a disease for an extended period of time. Recipient mice were able to survive more than one treatment of 5-fluorouracil (5-FU) at a dose that normally eliminates cycling hemopoietic progenitor cells; subsequently, transduced HSCs could become activated and undergo clonal expansion, resulting in abl-induced leukemic development. The disease developed in these mice was transplantable. Upon engraftment into secondary mice, previously unidentified abl-transduced HSC clones appeared. These data suggest the presence of an abl-suppressive mechanism in HSCs and have important implications to the pathogenesis of stem cell diseases and leukemic clonal evolution.

Deregulation of c-abl mediated cell growth after retroviral transfer and expression of antisense sequences.

To determine the role of c-abl during cell growth, we constructed a retrovirus vector alpha A, capable of expressing an antisense RNA directed against the abl mRNA. Based on v-abl-mediated 3T3 transformation assay, we showed that the number of transformed foci was reduced 50-94% when alpha A-infected 3T3 cells were superinfected with A-MuLV. Up to a 100% of inhibition could be observed when the time of infection was lengthened. Introduction of the antisense sequence into NIH3T3 cells resulted in reduction of growth rate. These cells entered into S phase from G1 phase of the cell cycle earlier in time than untransduced cells. Thus c-abl serves as a checkpoint during G1/S transition in the cell cycle, and its reduction resulted in deregulation of cell growth.

Endogenous growth factor patterns modulate hemopoietic lineage development.

Hemopoietic growth factors play an important role during stem cell differentiation, and multipotent hemopoietic cells expressing abl oncogenes can cause stem cell diseases in mice. To further elucidate the mechanism of disease development, we examined the initial changes of normal and abl-transduced progenitor cells early in culture, including the endogenous production of growth factors. From 2-3 days methylcellulose cultures, we isolated colonies of early cells and subjected them to RT-PCR analysis. They were found to produce endogenous IL-1 alpha and IL-4. Treatment of these early cells with the antisense oligonucleotides directed against the mRNA of the growth factors did not prevent colony formation. However, the percentage of pure macrophage colonies in cultures containing the antisense IL-1 alpha was increased from 26-60%. This effect was not observed when the antisense oligomers were added 2 days after initiation of culture. We also transduced the progenitor cells with retrovirus vectors carrying either a neor gene (N2) or a v-abl oncogene (A-MuLV or NSabl). After their culture in methylcellulose, we examined the types of colonies developed, growth factor expression by the early cells and their proliferation rate. While the ratio of erythroid to non-erythroid hemopoietic colonies in uninfected culture and N2-infected culture was 0.8, the ratio in A-MuLV-infected culture was 6.0, and in NSabl-infected culture, 3.1. RT-PCR analysis on colonies of abl-transduced cells from 2-3 day cultures indicated a reduction of IL-4 and IL-1 alpha in these cells, and they entered cell division sooner. Our data suggest that hematopoietic lineage development may be a function of the pattern of endogenous as well as exogenous growth factors, and alteration of this pattern either through antisense treatment or v-abl transduction affects the hemopoietic differentiation program.

Specific association of Type I c-Abl with Ran GTPase in lipopolysaccharide-mediated differentiation.

Each of several isoforms of c-Abl may be involved in different biological functions. Type I c-Abl has been shown to be involved in LPS-induced differentiation and Type IV c-Abl, apoptosis. Ran has recently been shown to be involved in LPS endotoxin signal transduction. Here we show that Type I c-Abl associates with Ran. Formation of this complex is specific, as Ran did not associate with the highly homologous Type IV c-Abl isoform. In non-stimulated lymphoid B cells, Type I c-Abl tyrosine kinase is inactive, whereas Type IV kinase is active. Formation of Type I c-Abl/Ran complex and activation of Type I c-Abl kinase activity are LPS dose-dependent. This complex is detectable in B cells of endotoxin-sensitive inbred mice but absent in B cells of endotoxin-resistant mice. These findings therefore suggest that Type I c-Abl and Ran are important targets in lipopolysaccharide-induced biological responses of hematopoietic cells.

Evidence for a multistep pathogenesis in the generation of tumorigenic cell lines from hemopoietic colonies exposed to Abelson virus in vitro.

The present studies were undertaken to investigate the ability of Abelson murine leukemia virus (A-MuLV) to transform cells derived in vitro from pluripotent hemopoietic progenitor cells of high proliferative potential. We now report that continuously growing, autonomous cell lines could be obtained from a high proportion of individually infected multilineage colonies generated in assays of spleen cells from normal adult mice if the infected cells were cocultivated for the first two to three months with irradiated NIH-3T3 cells. No lines were obtained if the 3T3 cell feeders were not initially present. Similar results were obtained when the cells exposed to virus were from multilineage colonies originating from isolated single cells obtained by replating small blast colonies. Characterization of the transformants and a number of derivative cloned sublines revealed the consistent presence of a mast cell phenotype, with some suggestion of macrophage differentiation in a few cases. All cell lines tested produced virus, showed a variable pattern of A-MuLV integration, and gave rise directly to tumors when injected subcutaneously, as shown by both Southern analysis and cytogenetic studies. The early absolute but transient dependence of these A-MuLV mast cell transformants on a fibroblast feeder suggests a multistep process in their evolution, in which the acquisition of autonomy from factors of mesenchymal cell origin may play an important role.

Blast colonies containing hemopoietic progenitor cells can give rise to Abelson virus (A-MuLV)-transformed cell lines.

We have established an in vitro system with which to examine the ability of Abelson murine leukemia virus (A-MuLV) to infect early hemopoietic progenitor cells. Blast cell colonies containing less than 100 cells were shown to contain up to 85% of cells with secondary hemopoietic colony-forming ability. Infection of cells from these blast colonies resulted in generation of transformed mast cell lines when a feeder was provided. Morphological examination of cells taken from infected cultures at various times postinfection indicated a progression of cellular differentiation to the mast cell lineage. Southern analysis on early subclones of transformed cells from two wells, using a v-abl specific probe, indicated a unique pattern of viral integration amongst subclones, suggesting that all subclones had derived from a single cell in each well. Similar results were observed with helper-free Abelson virus obtained by transfecting psi 2 cells with P160 A-MuLV proviral DNA. These data indicate that hemopoietic progenitor cells can be infected by A-MuLV and subsequently in our in vitro culture condition give rise to transformed mast cell lines.

Transduction of rIL-2 expanded CD4+ and CD8+ ovarian TIL-derived T cell lines with the G1Na (neor) replication-deficient retroviral vector.

We have expanded ovarian tumor-infiltrating lymphocytes (TIL) in low concentrations of recombinant interleukin-2 (rIL-2) to conduct intraperitoneal adoptive immunotherapy trials in patients with ovarian cancer. We have previously demonstrated that certain T cell lines and clones derived from ovarian TIL exhibit in vitro autologous tumor-specific cytotoxicity and/or cytokine production (interferon-gamma, tumor necrosis factor-alpha) preferentially in response to autologous tumor cells. Studies that utilize a marker gene introduced into the DNA of TIL can provide useful information on specific uptake or localization of TIL at tumor sites and on the survival of TIL in vivo. We have conducted a series of preclinical experiments in which we have successfully transfected TIL with G1Na, which encodes the gene for neomycin phosphotransferase (neoR). NeoR was detected in at least 10% of CD8+ cells (mean = 10.4%) and between 2.5 and 20% of CD4+ TIL (mean = 8.5%). Transduction of ovarian TIL with G1Na caused no substantial changes to the T cell phenotypes or in vitro cytotoxicities against ovarian and hematogenous tumor cell targets, or on the rIL-2 requirements of TIL for growth and proliferation. In addition, the intact G1Na provirus in transduced TIL cells was rescuable by replication-competent retrovirus and was transferred into the genome of NIH-3T3 fibroblasts, which were rendered resistant to G418. An enhanced polymerase chain reaction (PCR) procedure utilizing detection by ethidium bromide staining was developed. The enhanced PCR detected 1 in 100,000 neoR-labeled cells. Furthermore, detection of the G1Na genome in transduced TIL by in situ hybridization with an RNA probe provided evidence for expression of the neoR gene in transduced TIL. Results obtained from these studies suggest that ovarian TIL-derived T cell lines transduced with the neoR gene post infection with the G1Na retroviral vector can be utilized to examine the in vivo trafficking pattern of ovarian TIL-derived T cell lines expanded in low concentrations of rIL-2 and their survival.

The involvement of Ran GTPase in lipopolysaccharide endotoxin-induced responses.

By functional cloning, we have established that Ran GTPase is involved in LPS-induced signal transduction. This has been accomplished by several functional comparisons of the two cDNAs, Lps(n)/Ran (or RanT/n) and Lps(d)/Ran (or RanC/d), which were isolated from cDNA libraries of LPS responder and hyporesponder mice, respectively. The letter n refers to the "normal" phenotype and the letter d refers to the "deficient" phenotype. Consistent with our previous results, more animal studies indicated that adenoviral transduction of RanC/d cDNA, but not RanT/n cDNA, into sensitive mice conferred significant resistance against endotoxin challenge. Thus the incorporation of RanC/d cDNA into gene therapy protocols as a therapeutic sequence remains very attractive. At steady state, hematopoietic cells transduced with RanC/d cDNA led to about a 10-fold increase in exogenous Ran protein compared with RanT/n cDNA. Furthermore, our cumulative data suggest that a slight elevation of Ran protein in B cells enhances LPS responsiveness, but the same elevation of Ran in macrophages does not. On the other hand, a high level of overexpression of Ran in both macrophages and B cells down-regulates LPS signal transduction. Thus LPS-induced signal transduction in macrophages and B cells is likely to occur via different signaling pathways.

Elective carotid artery stenting in the presence of contralateral occlusion.

Significant carotid stenosis in the presence of an occluded contralateral artery has a poor prognosis with medical therapy alone. Carotid cross clamping during surgical endarterectomy results in critical flow reductions in patients with inadequate collateral flow, and represents a significant risk for procedural strokes. Carotid stenting is being evaluated as an alternative to endarterectomy. We describe the immediate and late outcome of a series of 26 patients treated with carotid stenting in the presence of contralateral carotid occlusion. The mean age of the patients in this group was 65 +/- 9 years, 23 (89%) were men and 10 (39%) were symptomatic from the vessel treated. The procedural success of carotid stenting in this group of patients was 96%. The mean diameter stenosis was reduced from 76 +/- 15% to 2.8 +/- 5%. There was 1 (3.8%) minor stroke in a patient who developed air embolism during baseline angiography. At late follow-up there was no neurologic event in any patient at a mean of 16 +/- 9.5 months after the procedure. Thus, carotid stenting of lesions with contralateral occlusion can be performed successfully with a low incidence of procedural neurologic complications and late stroke.

Efficacy of coronary stenting in the management of cardiac allograft vasculopathy.

We undertook a study to determine the efficacy of stents in reducing restenosis in cardiac allograft vasculopathy. The result shows that coronary stenting significantly reduces restenosis in cardiac allograft vasculopathy compared with balloon angioplasty alone.

Western Australian cigarette smokers have fewer small lung nodules than North Americans on CT screening for lung cancer.

To determine the prevalence of small lung nodules on low-dose helical computed tomography (CT) in a Western Australian cohort of asymptomatic long-term cigarette smokers and to compare this with a large, similarly derived cohort of North Americans from the Mayo Clinic Lung Cancer Screening Trial. Forty-nine asymptomatic long-term cigarette smokers of minimum age 50 years underwent a low-dose 64-slice helical CT of the lungs. Images were viewed on a soft copy reporting station with thin section axial and coronal images, maximum intensity projection images, and advanced image manipulation tools. The prevalence of all nodules was 39%, significantly lower than the Mayo Clinic cohort prevalence of 51% (P < 0.01, Fisher's exact test), despite the use of more advanced imaging technology and image manipulation designed to increase the sensitivity for nodules. The prevalence of small nodules in asymptomatic long-term cigarette smokers in Western Australia is high, though significantly less than that found in a large study in North America. The authors postulate this is due to the relatively low rates of mycobacterium tuberculosis and soil-derived fungal pulmonary infections in Western Australia, as well as a lower degree of urban air pollution.

Brucellosis in a Singaporean with prolonged fever.

Brucellosis, a zoonotic disease of worldwide distribution, is common in many developing countries as well as in countries of the Mediterranean basin. We report brucellosis in a 52-year-old man, who had a recent travel history to Saudi Arabia, and who presented with prolonged fever and deranged liver enzymes. In view of the rarity of brucellosis and its potential life-threatening complications, patients returning from an endemic country need to be questioned for possible Brucella exposure, to ensure that diagnostic tests and treatment are carried out in a timely fashion. In addition to notifying the authorities, the clinician should also warn the laboratory early as cultures of brucellosis are highly transmissible and are one of the most common laboratory-acquired infections.

Retroviral transfer and expression of the interleukin-3 gene in hemopoietic cells.

A recombinant retrovirus containing the interleukin-3 (IL3) coding sequence and the neomycin-resistance gene (Neor) has been generated. Infection of fetal liver cells with the IL3 retrovirus, but not with the N2 parental virus, resulted in the formation of factor-independent, NeoR colonies containing various types of differentiated hemopoietic cells. Established cell lines could be generated from these mixed hemopoietic colonies. These cell lines contained the unrearranged viral genome, produced viral IL3, and secreted the growth factor; however, they were not tumorigenic. Identical results were obtained from infection of two factor-dependent cell lines with the IL3 virus, except that these clones all became tumorigenic. These data indicate that endogenous IL3 production can support normal differentiation and immortalization of primary hemopoietic cells, or, in previously immortalized cells, can lead to tumorigenicity.