Pulmonary function following total body irradiation (with or without lung shielding) and allogeneic peripheral blood stem cell transplant

Our purpose was to determine if total body irradiation (TBI) with lung dose reduction protects against subsequent radiation-induced deterioration in pulmonary function. Between July 1997 and August 2004, 181 consecutive patients with hematologic malignancies received fractionated TBI before allogeneic peripheral blood stem cell transplant. The first 89 patients were treated to a total dose of 13.6 Gy. Thereafter, total body dose was decreased to 12 Gy with lung dose reduction to 9 or 6 Gy. All patients underwent pulmonary function test evaluation before treatment, 90 days post-treatment, then annually. Median follow-up was 24.0 months. Eighty-nine patients were treated with lung shielding, and 92 without. At 1-year post transplant, there was a small but significant difference in lung volume measurements between patients with lung shielding and those without. This was not observed at the 2-year time point. When stratified by good (>100% predicted) or poor (</=100% predicted) baseline lung function, patients with poor function demonstrated protection at 1 year with lung shielding, while those with good initial lung function did not. TBI with or without lung dose reduction has a small but statistically significant effect on pulmonary function measured at 1 year but not 2 years post irradiation.

Pretreatment pulmonary function tests predict risk of mortality following fractionated total body irradiation without lung dose reduction prior to stem cell transplant

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Background: Peripheral blood stem cell transplantation (PBSCT) is a key component in the treatment of various malignancies. Preparatory regimens for PBSCT often include total body irradiation (TBI). Pulmonary toxicity is often prominent, and is felt to be related to total lung dose and dose rate. The Radiation Oncology Branch of the National Institute of Health initially administered TBI without lung shielding, however shielding was added in 2002. Pulmonary function testing (PFT) was undertaken both before and after stem cell transplant and TBI for all patients. The PFT results were analysed to test the hypothesis that TBI patients with pre-treatment combined ventilation/diffusion capacity deficits, defined as both FEV1 and DLCO below 100% predicted, would benefit most from reduction of lung dose. Methods: From 1997–2004, 146 consecutive patients with hematologic malignancies received fractionated TBI before PBSCT. The first 85 patients were treated without lung dose reduction to 13.6 Gray (Gy). Thereafter, total body dose was decreased to 12 Gy (1.5 Gy BID for 4 days). Initially, lung dose was limited to 9 Gy by use of lung shielding. Later lung dose was reduced to 6 Gy. All patients received PFTs prior to treatment, 90 days after treatment, and annually. Results: Median F/U was 44 months (range 12–90 months). Sixty-one patients had combined ventilation/diffusion capacity deficits defined as both a forced expiratory volume in the first second (FEV1) and a diffusion capacity of carbon dioxide (DLCO) less than 100% predicted. Of these 61, 27 had lung dose reduction and 34 did not. One-year survival was 71% versus 50% with and without lung dose reduction respectively (log rank test p=0.042). Eighty-five patients had FEV1 and/or DLCO greater than or equal to 100% predicted; 34 were treated with lung dose reduction and 51 without. In both groups, 1 year survival was 70%. Conclusions: Among patients treated without lung dose reduction, survival was significantly worse among those with pretreatment combined ventilation/diffusion capacity deficits. Among those with combined ventilation/diffusion capacity deficits, lung dose reduction significantly improved survival.

No significant financial relationships to disclose.

siRNA targeting the leader sequence of SARS-CoV inhibits virus replication

SARS-CoV (the SARS-Associated Coronavirus) was reported as a novel virus member in the coronavirus family, which was the cause of severe acute respiratory syndrome. Coronavirus replication occurs through a unique mechanism employing Leader sequence in the transcripts when initiating transcription from the genome. Therefore, we cloned the Leader sequence from SARS-CoV(BJ01), which is identical to that identified from SARS-CoV(HKU-39849), and constructed specific siRNA targeting the Leader sequence. Using EGFP and RFP reporter genes fused with the cloned SARS-CoV Leader sequence, we demonstrated that the siRNA targeting the Leader sequence decreased the mRNA abundance and protein expression levels of the reporter genes in 293T cells. By stably expressing the siRNA in Vero E6 cells, we provided data that the siRNA could effectively and specifically decrease the mRNA abundance of SARS-CoV genes as analyzed by RT-PCR and Northern blot. Our data indicated that the siRNA targeting the Leader sequence inhibited the replication of SARS-CoV in Vero E6 cells by silencing gene expression. We further demonstrated, via transient transfection experiments, that the siRNA targeting the Leader sequence had a much stronger inhibitory effect on SARS-CoV replication than the siRNAs targeting the Spike gene or the antisense oligodeoxynucleotides did. This report provides evidence that targeting Leader sequence using siRNA could be a powerful tool in inhibiting SARS-CoV replication.

Optically stimulated luminescent glass optical fibre dosemeter

An optical fibre radiation dosemeter has been developed that utilises optically stimulated luminescence and scintillation to provide independent, remote, real-time dose measurements. The radiation sensitive element consists of a 1 mm long, 0.4 mm diameter piece of copper-ion-doped fused quartz that is attached to a 1 m length of commercial optical fibre. The dosemeter probe is 0.6 mm in diameter and is flexible enough to be used in standard medical catheters for internal radiation dose measurements. A four-channel dosemeter system has been built and characterised under conditions typical of a radiotherapy environment. The device exhibits a linear response over the range of doses from 0.01 Gy to 10 Gy. The dosemeter responds identically to both electrons and photons in the range from 4 to 20 MV and the calibration was retained to within +/-2% over a period of 4 weeks. The fibre dosemeter has been used successfully to verity doses received by three patients receiving radiotherapy treatments.

Three-dimensional structure of CA1 pyramidal cells in rat hippocampus--optical recording of LSM and computer simulation of fractal structure

The optical recording of three-dimensional (3-D) reconstruction of CA1 pyramidal cells was derived from the studies on the CA1 region of the hippocampus in adult male Wistar rats. The recording was produced by the Confocal Laser Scan Microscope (LSM-10). The attemption was to outline the morphological neural network of CA1 pyramidal cells organization, following the trail of axo-dendritic connections in 3-D spatial distributions among neurons. The fractal structure of neurons with their dendritic and axonal trees using fractal algorithm was noticed, and 2-18 simulated cells were obtained using PC-486 computer. The simulational cells are similar in morphology to the natural CA1 hippocampal pyramidal cells. Therefore, the exploitation of an advanced neurohistological research technique combining optical recording of the LSM-10 and computer simulation of fractal structure can provide the quantitative fractal structural basis for chaosic dynamics of brain.

Quantitative integration of the Salmonella microsuspension assay with supercritical fluid extraction of model airborne vapor-phase mutagens

Vapor-phase mutagens are potentially a major class of toxic contaminants in ambient and indoor air. These compounds are not routinely analyzed due to a lack of an established integrated methodology to quantitatively trap, extract and test the compounds in a bioassay. In a previous report, we emphasized the trapping of volatile and semi-volatile mutagens and the extraction of these compounds using supercritical carbon dioxide (CO2). In the present study, we discuss the use of a bioassay for the quantitation of the model mutagens, ethylene dibromide(EDB) and 4-nitrobiphenyl (4-NB), trapped from an airstream. The compounds EDB and 4-NB were released into a controlled airstream, trapped on XAD-4 adsorbent, and were extracted using supercritical CO2. The extract was tested in a microsuspension modification of the Ames Salmonella/microsome test adapted for volatile compounds. Linear dose-response relationships were obtained for supercritical CO2-extracted EDB using tester strain TA100 (+/- S9) and for 4-NB using tester strains TA98 and TA100 (-S9). Standard dose-response curves with known amounts of the compounds were also determined for comparison with measured amounts of the model compounds collected in an airstream. The gas chromatographic (GC)- and bioassay-determined quantities of EDB and 4-NB were highly correlated, accurate and precise. For example, bioassay-determined EDB concentrations were within 10% of the GC-determined concentrations. Our results demonstrate that the integrated methodology for vapor-phase mutagens developed in this study would be useful for quantitative analysis of these and related airborne vapor-phase mutagenic compounds.

Increased c-Ki-ras expression in hamster lung exposed to N-nitrosodiethylamine and hyperoxia as detected by the polymerase chain reaction

Neuroendocrine lung cancers can be induced in hamsters within 8-12 weeks by combined exposure to N-nitrosodiethylamine (DEN) and hyperoxia. The expression of the c-Ki-ras gene in this lung cancer model was studied using polymerase chain reaction analysis of mRNA (RNA/PCR). We used four different groups of hamsters, exposed for 6 weeks to DEN with hyperoxia (60% oxygen), DEN, hyperoxia, or ambient air, respectively. Total RNA was isolated from lung tissues and cDNA made prior to PCR amplification. A 234-bp product was amplified from c-Ki-ras cDNA and quantitated using scanning laser densitometry. The data obtained were normalized to the expression of the house keeping gene B-actin. The c-Ki-ras products were present after amplification of all hamster lung RNA samples. The hamster lungs exposed to DEN with hyperoxia displayed higher c-Ki-ras protooncogene expression than hamsters exposed to DEN, hyperoxia, or ambient air alone. Since the animals studied were sacrificed at 6 weeks, prior to the appearance of tumors, we conclude that this increased expression may indicate a role for c-Ki-ras in the initial steps in malignant transformation of neuroendocrine cells.