Search

This study was designed to test the effects of pursed lips breathing (PLB) during exercise in patients with chronic obstructive pulmonary disease (COPD) who did not spontaneously perform PLB. Sixtynine COPD patients, mean FEV1 (SD) 1.09 (0.5), age 68 (51–83) were recruited to the study. They performed three incremental shuttle walk tests (ISWT). The first walk was designed to identify natural PLBs and the next two walks were performed in a random order; ISWT + PLB or ISWT whilst breathing normally. Measures of respiratory rate (RR), breathlessness and oxygen saturation were taken before and after walks. Data was analysed using the t-test. Fifteen patients demonstrated PLB on baseline ISWT and were therefore excluded from further walking tests although baseline data was included in the analysis. There was no significant difference between walks, mean (SD), 298.5 (173.7) PLB and non-PLB; 292.5 (161.9) nor any difference in dyspnoea. There was a significant reduction in end exercise RR and recovery time with PLB, mean difference (95% CI); 6.2 (4.5–7.9) and 24.9 (2.8–47.0) seconds, respectively. Patients who showed a good response with the PLB walk (41%) had significantly higher baseline breathlessness, Borg score, mean (SD), 1.5 (1.0) versus 0.74 (0.96) (P = 0.02). Natural PLB patients demonstrated lower exercise tolerance on the baseline walk (P = 0.01) and a trend towards greater resting breathlessness than those who did not. This study shows PLB during exercise and recovery results in lower post exercise RR and speeds return to pre exercise breathlessness, compared with exercise and non-PLB. Reductions in RR appear to be greatest in those patients with resting breathlessness. [ABSTRACT FROM AUTHOR]

Morphological revertants of the avian erythroblastosis virus (AEV)-transformed rat cell line ATla were isolated and characterised. The revertants are similar to the uninfected parental rat cell line in that they have regained an organized cytoskeleton and they are no longer capable of anchorage-independent growth. The pattern of integrated viral DNA in the revertants is indistinguishable from that of the transformed parent. However, the revertants do not express the integrated viral genome at either the mRNA or protein level. Phenotypic reversion thus is probably .due to reduced transcription of the AEV-transforming gene below a threshold necessary to induce morphological transformation.

The class I major histocompatibility complex (MHC) antigens are highly polymorphic cell-surface proteins whose expression is essential for the cellular immune response against virus-infected, abnormal and foreign cells. Transformation of primary rat cell cultures by the oncogenic adenovirus 12 (Ad12) results in suppression of the transplantation antigens, thus enabling the transformed cells to escape the immune response and efficiently form tumours in vivo. In contrast, transformation of the same cells with the non-oncogenic adenovirus 5 (Ad5) does not suppress the transplantation antigens and, consequently, they elicit an effective (MHC-restricted) immune response. Here, however, we show that infection of mouse embryo cells with both viruses initially increases the level of transcripts from the H-2Kb transplantation antigen gene. Both the adenovirus E1a (12S RNA) and E1b genes are required for activation of the H-2K gene and measurement of the relative rate of transcription indicates that the increase in the level of H-2K messenger RNA following infection is at least in part due to a gene-specific transcriptional activation. The newly transcribed H-2Kb mRNA is then properly transported to the cytoplasm.

The L-cell virion (LCV) has been purified from supernatant fluids of mouse L cells grown in suspension culture. The virion is similar to other RNA tumor viruses by several criteria: (i) the density of the virion is 1.16 g/cm(3); (ii) the virion appears as a rounded membranous particle with an outer diameter of 146.7 +/- 11.8 nm, and contains knobs (7-nm diameter) over its surface; (iii) 15 polypeptides (ranging in molecular weight from 7,000 to 110,000) are detectable after electrophoresis of virion protein in sodium dodecyl sulfate-polyacrylamide gels; (iv) three species of RNA can be isolated-high molecular weight (80 to 88s) (50%), 7s (35%) and 4s (15%); (v) heat denaturation of the high-molecular-weight RNA yields a heterogeneous population of molecules (20 to 35s) as well as a 7s and 4s species. Despite the general similarity to infectious RNA tumor viruses, LCV is apparently defective as evidenced by the fact that it does not induce tumors in animals or transform normal mouse cells in vitro (Kindig and Kirsten [17]). The defective nature of the LCV might be related to the fact that assays for DNA polymerase in the virion showed only a negligible activity when compared to Rous sarcoma virus.