Ultra-Violet Light Emission from HPV-G Cells Irradiated with Low Let Radiation From 90Y; Consequences for Radiation Induced Bystander Effects

In this study, we aimed to establish the emission of UV photons when HPV-G cells and associated materials (such as the cell substrate and cell growth media) are exposed to low LET radiation. The potential role of UV photons in the secondary triggering of biological processes led us to hypothesize that the emission and absorption of photons at this wavelength explain some radiation induced “bystander effects” that have previously been thought to be chemically mediated. Cells were plated in Petri-dishes of two different sizes, having different thicknesses of polystyrene (PS) substrate, and were exposed to β-radiation from ⁹⁰Y produced by the McMaster Nuclear Reactor. UV measurements were performed using a single photon counting system employing an interference-type filter for selection of a narrow wavelength range, 340±5 nm, of photons. Exposure of the cell substrates (which were made of polystyrene) determined that UV photons were being emitted as a consequence of β particle irradiation of the Petri-dishes. For a tightly collimated β-particle beam exposure, we observed 167 photons in the detector per unit μCi in the shielded source for a 1.76 mm thick substrate and 158 photons/μCi for a 0.878 mm thick substrate. A unit μCi source activity was equivalent to an exposure to the substrate of 18 β-particles/cm² in this case. The presence of cells and medium in a Petri-dish was found to significantly increase (up to a maximum of 250%) the measured number of photons in a narrow band of wavelengths of 340±5 nm (i.e. UVA) as compared to the signal from an empty control Petri-dish. When coloured growth medium was added to the cells, it reduced the measured count rate, while the addition of transparent medium in equal volume increased the count rate, compared to cells alone. We attribute this to the fact that emission, scattering and absorption of light by cells and media are all variables in the experiment. Under collimated irradiation conditions, it was observed that increasing cell density in medium of fixed volume resulted in a decrease in the observed light output. This followed a roughly exponential decline. We suggest that this may be due to increased scattering at the cell boundary and absorption of the UV in the cells. We conclude that we have measured UVA emitted by cells, cell medium and cell substrates as a consequence of their irradiation by low LET β-particle radiation. We suggest that these secondary UV photons could lead to effects in non-targetted cells. Some effects that had previously been attributed to a chemically mediated “bystander effect” may in fact be due to secondary UV emission. Some radiation bystander effect studies may require re-interpretation as this phenomenon of UV emission is further investigated.     

Association between hospital volume and network membership and an analgesia, sedation and delirium order set quality score: a cohort study

ABSTRACT: INTRODUCTION: Protocols for the delivery of analgesia, sedation and delirium care of the critically ill, mechanically ventilated patient have been shown to improve outcomes but are not uniformly used. The extent to which elements of analgesia, sedation and delirium guidelines are incorporated into order sets at hospitals across a geographic area is not known. We hypothesized that both greater hospital volume and membership in a hospital network are associated with greater adherence of order sets to sedation guidelines. METHODS: Sedation order sets from all nonfederal hospitals without pediatric designation in Washington State that provided ongoing care to mechanically ventilated patients were collected and their content systematically abstracted. Hospital data were collected from Washington State sources and interviews with ICU leadership in each hospital. An expert-validated score of order set quality was created based on the 2002 four-society guidelines. Clustered multivariable linear regression was used to assess the relationship between hospital characteristics and the order set quality score. RESULTS: Fifty-one Washington State hospitals met the inclusion criteria and all provided order sets. Based on expert consensus, 21 elements were included in the analgesia, sedation and delirium order set quality score. Each element was equally weighted and contributed one point to the score. Hospital order set quality scores ranged from 0 to 19 (median = 8, interquartile range 6 to 14). In multivariable analysis, a greater number of acute care days (P = 0.01) and membership in a larger hospital network (P = 0.01) were independently associated with a greater quality score. CONCLUSIONS: Hospital volume and membership in a larger hospital network were independently associated with a higher quality score for ICU analgesia, sedation and delirium order sets. Further research is needed to determine whether greater order-set quality is associated with improved outcomes in the critically ill. The development of critical care networks might be one strategy to improve order set quality scores.     

Multicenter phase 2 trial of thalidomide in relapsed/refractory multiple myeloma: adverse prognostic impact of advanced age

Relapsed or refractory multiple myeloma has a poor outlook. Some patients respond to thalidomide; however, criteria for predicting response have not been conclusively identified. We initiated a prospective multicenter phase 2 trial in patients with relapsed/refractory myeloma using thalidomide up to the maximum dose, 800 mg/d. Interferon-alpha-2B (1.5-3.0 x 10(6) U, subcutaneously, 3 times per week) was added at week 12 if disease was responsive or stable. Patients intolerant of interferon continued thalidomide alone. Thalidomide with or without interferon was continued until disease progression. Objectives were to determine toxicity, response rate (RR), progression-free survival (PFS), and overall survival (OS) and to elucidate relevant prognostic factors. We enrolled 75 patients, with median age 64 years (range, 36-83 years). Median individual maximum-tolerated dose of thalidomide was 600 mg/d; 41% reached 800 mg/d. Overall RR was 28%, and 55% stable disease (SD). The only predictor for response was age 65 years or younger (38% versus 17%; P =.043). At 18 months median follow-up, the actuarial median PFS and OS were 5.5 and 14.6 months, respectively. Multivariate analysis for OS demonstrated age exceeding 65 years (median, 9.2 months versus longer than 26 months; P =.011), raised serum lactate dehydrogenase (P =.002), and raised serum creatinine (P =.007) predicted inferior outcomes. Nineteen patients received interferon. Ten discontinued owing to toxicity. Four of 12 patients who received interferon for longer than 4 weeks were converted from SD to partial response. Our findings confirm substantial activity of thalidomide in relapsed/refractory myeloma. Interferon may improve response in selected patients, but is often not tolerated. The inferior outcome demonstrated in those with the identified prognostic factors is important in planning management for such patients.     

Inhibition of Hsp90 activates osteoclast c-Src signaling and promotes growth of prostate carcinoma cells in bone

Hsp90 inhibitors are being evaluated extensively in patients with advanced cancers. However, the impact of Hsp90 inhibition on signaling pathways in normal tissues and the effect that this may have on the antitumor activity of these molecularly targeted drugs have not been rigorously examined. Breast and prostate carcinomas are among those cancers that respond to Hsp90 inhibitors in animal xenograft models and in early studies in patients. Because these cancers frequently metastasize to bone, it is important to determine the impact of Hsp90 inhibitors in the bone environment. In the current study, we show that, in contrast to its activity against prostate cancer cells in vitro and its inhibition of s.c. prostate cancer xenografts, the Hsp90 inhibitor 17-AAG stimulates the intraosseous growth of PC-3M prostate carcinoma cells. This activity is mediated not by a direct effect on the tumor but by Hsp90-dependent stimulation of osteoclast maturation. Hsp90 inhibition transiently activates osteoclast Src kinase and promotes Src-dependent Akt activation. Both kinases are key drivers of osteoclast maturation, and three agents that block osteoclastogenesis, the Src inhibitor dasatinib, the bisphosphonate alendronate, and the osteoclast-specific apoptosis-inducer reveromycin A, markedly reduced 17-AAG-stimulated tumor growth in bone. These data emphasize the importance of understanding the complex role played by Hsp90 in regulating signal transduction pathways in normal tissues as well as in cancer cells, and they demonstrate that drug-dependent modulation of the local tumor environment may profoundly affect the antitumor efficacy of Hsp90-directed therapy.     

Serum Immune Complexes and Disease

Summary: The solid phase Clq radioimmunoassay was used to detect immune complexes in sera from patients with systemic lupus erythematosus (14/25), rheumatoid arthritis (4/5), vasculitis (5/15), infective endocarditis (2/2), acute rheumatic fever (2/3), pre-eclamptic toxaemia (0/14), lung cancer (3/7), glomerulonephritis (26/98) and renal transplant patients (0/5). The best correlation with disease activity was seen in systemic lupus erythematosus and infective endocarditis where serial immune complex determinations were clearly of value in monitoring therapy. The findings in primary glomerulonephritis indicate only a limited usefulness of the assay in that serum immune complexes were detected in a minority (22/73) of patients with glomerular immune deposits. In particular the data do not support a role for Clq fixing immune complexes in the pathogenesis of membranous glomerulonephritis or in pre-eclamptic toxaemia.