Hospice patients' participation in choice experiments to value supportive care outcomes.

BACKGROUND: Values used in economic evaluation are typically obtained from the general public, which is problematic when measures are to be used with people experiencing a life-course stage such as the end of life. OBJECTIVE: To assess the feasibility of obtaining values for the ICECAP-Supportive Care Measure (SCM) from patients receiving advanced supportive care through a hospice. METHODS: Participants completed eight best-worst scaling questions in a think-aloud interview to explain choices in different hypothetical end-of-life scenarios. Three independent raters identified errors in completion of the best-worst scaling task, and thematic analysis of associated qualitative data was undertaken to explore task difficulty and choices. RESULTS: Twelve hospice patients were recruited. Most were able to complete the task and prioritise aspects of supportive care with either no difficulty (n=50%) or difficulty in just one of the eight scenarios (n=25%). Two patients (n=17%) were unable to comprehend the hypothetical nature of the task. The qualitative data confirmed there was good engagement with the task and identified the importance the respondents attached to maintaining dignity. CONCLUSION: The findings suggest that people at the end of life will be able to complete a short, interviewer-administered, best-worst scaling task. To maximise engagement, it is recommended that the task is short and initiated with an example. Scenarios are best presented on show-cards in large print. A full evaluation of the ICECAP-SCM with those at the end of life is feasible.

Using discrete choice experiments to understand preferences for quality of life. Variance-scale heterogeneity matters.

Health services researchers are increasingly using discrete choice experiments (DCEs) to model a latent variable, be it health, health-related quality of life or utility. Unfortunately it is not widely recognised that failure to model variance heterogeneity correctly leads to bias in the point estimates. This paper compares variance heterogeneity latent class models with traditional multinomial logistic (MNL) regression models. Using the ICECAP-O quality of life instrument which was designed to provide a set of preference-based general quality of life tariffs for the UK population aged 65+, it demonstrates that there is both mean and variance heterogeneity in preferences for quality of life, which covariate-adjusted MNL is incapable of separating. Two policy-relevant mean groups were found: one group that particularly disliked impairments to independence was dominated by females living alone (typically widows). Males who live alone (often widowers) did not display a preference for independence, but instead showed a strong aversion to social isolation, as did older people (of either sex) who lived with a spouse. Approximately 6-10% of respondents can be classified into a third group that often misunderstood the task. Having a qualification of any type and higher quality of life was associated with smaller random component variances. This illustrates how better understanding of random utility theory enables richer inferences to be drawn from discrete choice experiments. The methods have relevance for all health studies using discrete choice tasks to make inferences about a latent scale, particular QALY valuation exercises that use DCEs, best-worst scaling and ranking tasks.

The differential staurosporine-mediated G1 arrest in normal versus tumor cells is dependent on the retinoblastoma protein.

Previously, we reported that breast cancer cells with retinoblastoma (pRb) pathway-defective checkpoints can be specifically targeted with chemotherapeutic agents, following staurosporine-mediated reversible growth inhibition in normal cells. Here we set out to determine if the kinetics of staurosporine-mediated growth inhibition is specifically targeted to the G(1) phase of cells, and if such G(1) arrest requires the activity of wild-type pRb. Normal human mammary epithelial and immortalized cells with intact pRb treated with low concentrations of staurosporine arrested in the G(1) phase of the cell cycle, whereas pRb-defective cells showed no response. The duration of G(1) and transition from G(1) to S phase entry were modulated by staurosporine in Rb-intact cells. In pRb(+) cells, but not in Rb(-) cells, low concentrations of staurosporine also resulted in a significant decrease in cyclin-dependent kinase 4 (CDK4) expression and activity. To directly assess the role of pRb in staurosporine-mediated G(1) arrest, we subjected wild-type (Rb(+/+)) and pRb(-/-) mouse embryo fibroblasts (MEFs) to staurosporine treatments. Our results show that whereas Rb(+/+) MEFs were particularly sensitive to G(1) arrest mediated by staurosporine, pRb(-/-) cells were refractory to such treatment. Additionally, CDK4 expression was also inhibited in response to staurosporine only in Rb(+/+) MEFs. These results were recapitulated in breast cancer cells treated with siRNA to pRb to down-regulate the pRb expression. Collectively, our data suggest that treatment of cells with nanomolar concentrations of staurosporine resulted in down-regulation of CDK4, which ultimately leads to G(1) arrest in normal human mammary epithelial and immortalized cells with an intact pRb pathway, but not in pRb-null/defective cells.

Flow cytometry after bromodeoxyuridine labeling to measure S and G2+M phase durations plus doubling times in vitro and in vivo.

This protocol describes methods for calculating the proliferative parameters of cell populations. The basis of the technique is to label cells, either in vitro or in vivo, with halogenated thymidine analogs, such as bromodeoxyuridine (BrdU). Bivariate DNA-BrdU flow cytometry is used to analyze the BrdU-labeled and unlabeled cells. The enumeration of specific cohorts of cells that either have or have not divided in the interval between labeling and cell/tissue sampling permits the calculation of the potential doubling time (T(pot)) of the population, plus the durations of DNA synthesis (T(S)) and the G2+M phase (T(G2+M)) of the cell cycle. The method provides information that is not otherwise available, namely inhibition of DNA synthesis and the separate evaluation of cell-cycle effects in BrdU-labeled and unlabeled subpopulations. Ethanol-fixed samples take 1 d to prepare and stain, and reliable parameter estimates might be obtained from measurements made at a single time point after labeling.

Cell cycle kinetic dysregulation in HIV-infected normal lymphocytes.

BACKGROUND: Viruses alter cellular gene transcription and protein binding at many steps critical for cell cycle regulation to optimize the milieu for productive infection. Reasoning that virus-host cell interactions would result in perturbations of cell cycle kinetics, measurement of the duration of the phases of the cell cycle in normal T lymphocytes infected with human immunodeficiency virus (HIV) was undertaken. METHODS: Flow cytometric measurement of bromodeoxyuridine-labeled and DNA content-stained cells at multiple points through the cell cycle allowed estimation of the fraction of cells in each phase, the potential doubling-time, and the durations of S and G(2)/M phases. Separate analysis of the HIV(+) and HIV(-) populations within the infected cultures was performed based on intracellular, anti-HIV core p24 antibody labeling. A novel mathematical model, which accounted for cell loss, was developed to estimate cell cycle phases. RESULTS: (a) S phase was prolonged in the HIV-1(SF2)-infected cells compared with control. (b) This delay in S phase was due to delay in the population of cells not expressing HIV-1 antigens (p24 negative). (c) Accumulation of cells in G(2)/M phase was confirmed in HIV-1-infected cultures and was proportional to the level of infection as measured by p24 fluorescent intensity. However, all mock and HIV-1-infected populations predicted to proceed through cell division demonstrated similar G(2)/M-phase durations. (c) Potential doubling times were longer in the infected cultures; in contrast, the p24(+) subpopulations accounted for this delay. This suggests an isolated delay in the G(0)/G(1) phase for that population of cells. CONCLUSIONS: Multiple phases of host cell cycle durations were affected by HIV-1(SF2) infection in this in vitro model, suggesting novel HIV-1 pathogenesis mechanisms. Prolonged S-phase durations in HIV-1 infected/p24(-) and G(0)/G(1)-phase durations in HIV-1 infected/p24(+) subpopulations require further study to identify mechanistic pathways.

Estimating cell death in G(2)M using bivariate BrdUrd/DNA flow cytometry.

BACKGROUND: In an accompanying paper (Asmuth et al.) it was found necessary to include cell death explicitly to estimate parameters of cell proliferation. The use of bivariate flow cytometry to estimate the phase durations and the doubling times of cells labeled with thymidine analogues is well established. However, these methods of analysis do not consider the possibility of cell death. This report demonstrates that estimating cell death in G(2)/M is possible. METHODS: Mathematical models for the experimental quantities, the fraction of labeled undivided cells, the fraction of labeled divided cells, and the relative movement were developed. These models include the possibility that, of the cells with G(2)/M DNA content, only a certain fraction will divide, with the remainder dying after some time T(R). Simulation studies were conducted to test the possibility of using simple methods to estimate phase durations and cell death rates. RESULTS: Cell death alters the estimates of phase transit times in a rather complex manner that depends on the lifetime of the doomed cells. However, it is still possible to obtain estimates of the phase durations of cells in S and G(2)/M and the death rates of cells in G(2)/M. CONCLUSIONS: The methods presented herein provide a new way to characterize cell populations that includes cell death rates and common measurements of cell proliferation.

Cellular kinetics of murine lung: model system to determine basis for radioprotection with keratinocyte growth factor.

PURPOSE: Normal tissue toxicity remains a dose limitation for cancer radiotherapy and chemoradiotherapy. Growth factors offer a novel means of mitigating normal tissue radiotoxicity. In particular, keratinocyte growth factor (rHuKGF), whose proliferative activity is restricted to epithelial cells, holds promise on the basis of the findings of preclinical models of epithelial cytoprotection and the clinical developments to date. We report the radioprotection of murine lung by an increase in tissue cellularity after rHuKGF-induced proliferation. METHODS AND MATERIALS: Flow cytometric and image analysis techniques after bromodeoxyuridine labeling were used to estimate proliferative parameters. Our specialized analytical methods measure not only labeling indexes, but also the durations of S and G(2)+M phases, potential doubling times, and the net cell production rate. Image analysis techniques were used to identify the specific cell types that were proliferating (type II pneumocytes). RESULTS: Lung labeling index control values (0.5%) rose to a maximum (5.5%) at 3 days after intratracheal rHuKGF, returning to normal by Day 7. The potential doubling time fell from 66 days to 4.4 days. The net cell production rate rose from a control value of 1%/d to >15%/d by Day 3. This resulted in a nearly twofold increase in alveolar epithelial cellularity, which remained significantly elevated on Day 7. Saline-treated control animals exhibited no significant changes in the proliferative parameter values or cellularity. On the basis of these data, mice were irradiated, solely to the thorax, with ranges of single doses of 250 kVp X-rays 7 days after either intratracheal administration of 5 mg/kg rHuKGF or phospate-buffered saline. This interval was chosen because the proliferative response of the type II cells was finished but the cellularity of the lung remained increased. Pretreatment with rHuKGF extended the latent period before onset of pneumonitis after all radiation doses. rHuKGF treatment 7 days before thoracic irradiation significantly protected against pneumonitis (median effective dose 13.7 Gy, 95% confidence limit 13.4-14.0) compared with the control pretreatment with phosphate-buffered saline (median effective dose 12.8 Gy, 95% confidence limit 12.6-13.1). CONCLUSION: The data showed that an increase in tissue cellularity, caused by rHuKGF treatment before irradiation, protected the lung from damage due to pneumonitis.

Modulating effect of keratinocyte growth factor on cellular kinetics of murine lung(I).

BACKGROUND & OBJECTIVE: Keratinocyte growth factor (KGF) causes the proliferation of type II pneumocytes in the lungs and confers protection against many external stimulation in the lung. Historically, the kinetic parameters, especially of slowly proliferating normal tissues, such as the lung, were difficult to measure. However, recently developed techniques made it possible to measure accurately the cellular kinetics in normal tissues. Flow cytometric techniques following bromodeoxyuridine (BrdUrd) incorporation into DNA of cells allow the accurate measurement of cellular proliferation. The purpose of this study was to measure the changes of the dynamic kinetics of normal lung tissue after treatment with KGF so as to build up the basis to prevent the occurrence of radiation-induced pneumonitis. METHODS: C3Hf/Kam mice were treated intratracheally (i.t.) with KGF (5 mg/kg) or the control (saline) and were sacrificed at 0, 1, 2, 3, 4, 5, and 7 days. The mice were labeled intraperitoneally (i.p.) with BrdUrd (60 mg/kg) at 20 minutes or 6 hours before sacrifice. Lungs were excised, fixed in 60% ethanol, digested to produce nuclei; and BrdUrd as well the total DNA content were labeled for flow cytometric analysis. The kinetic parameters including the labeling index (LI), duration of S-phase (T(S)), and potential doubling time (T(pot)) were measured by novel analytical methodology. Immunofluorescence staining was used to identify the specific cell type that was proliferating. RESULTS: (1)An optimum route for the administration (i.t.), dose (5 mg/kg), and time course of KGF to stimulate proliferation of type II pneumocytes in the lungs was established. (2)Lung LI control values (0.5%) rose to a maximum (5.5%) at 3 days after KGF treatment and returned to normal level on the 7(th) day. (3)Of the lung tissue, there is a dramatic reduction in T(pot) from 75.5 days to 4.7 days in the KGF-treated mice, while the saline-treated control mice exhibited no change in proliferative parameter values. CONCLUSION: KGF caused the proliferation of type II pneumocytes, followed with the elevated LI and reduced T(pot). This proliferative effect was transient and levels returned to normal level by the 7(th) day. The data obtained from this study would lay the groundwork for future investigation of KGF as a possible radioprotector of the lung in the field of radiation oncology.

A CD40 Signalosome anchored in lipid rafts leads to constitutive activation of NF-kappaB and autonomous cell growth in B cell lymphomas.

B cell lineage non-Hodgkin's lymphomas (NHL-B) are neoplastic B cells that show dysregulated B lymphocyte growth characteristics. Unlike normal B cells, aggressive NHL-B cells show constitutive expression of nuclear NF-kappaB by maintaining an assembled, scaffold-like signaling platform, called a Signalosome within the lipid raft microdomain, extending from the cell membrane. The CD40 Signalosome appears to be initiated through autochthonous production and cognate binding of CD154 (CD40L, gp39) to CD40 by the lymphoma cell. Constitutive expression of NF-kappaB in NHL-B can be downregulated by treatment with antibodies to CD40 or CD154 that disrupt Signalosomes, inhibit lymphoma cell growth, and induce cell death. CD40 Signalosomes may provide a potentially vulnerable target for therapeutic intervention in NHL-B cells.