Linear temporal and spatiotemporal stability analysis of two-layer falling films with density stratification

A detailed temporal and spatiotemporal stability analysis of two-layer falling films with density and viscosity stratification is performed by using the Chebyshev collocation method to solve the full system of linear stability equations. From the neutral curves Re(k) for the surface mode and the interface mode of instability, obtained for different density ratios gamma of the upper layer to the lower layer, it is found that smaller density ratios make the surface mode and the short-wave interface mode much more stable, and can even make the short-wave interfacial instability disappear. Moreover, through the study of the local growth rates of the spatiotemporal instability as a function of the ray velocity V , it is found that for not too small incline angles like theta=0.2, the two-layer flow is always convectively unstable, and there is a transition between long- and short-wave instabilities which is determined by the Briggs-Bers collision criterion. Due to the existence of the absolute Rayleigh-Taylor instability for gamma>0 and theta=0, a transition from convective to absolute instability can be detected at small incline angles, and the corresponding boundary curves are plotted for different Reynolds numbers, viscosity ratios, and incline angles. It is found that there exists a limit Reynolds number above which the two-layer film flow can only be convectively unstable for a fixed small incline angle. The spatial amplification properties of the convective waves are finally presented for both surface and interface modes.

Patient co-payments and use of prescription medicines

OBJECTIVE

To investigate how prescription co-payments influence the medicine use of Australian patients.

METHODS

Two surveys and an in-depth interview study were conducted in the Newcastle/Hunter region of New South Wales (NSW). A community-based survey explored how often prescription cost posed a barrier to prescription use. A general practice patient survey investigated the impact of prescription cost on the timing of medical consultations and prescription collection. Quantitative data were summarised using descriptive statistics; associations between household characteristics and outcomes were explored using odds ratios and chi square analysis. In-depth interviews were conducted to explore the role of prescription cost in medicine use. The interview data were qualitatively analysed for relevant themes using 'grounded theory'.

RESULTS

420 of 950 households (44%) participated in the community survey: 110 (26%) reported delaying visiting a GP, 85 (20%) not buying all of their prescription medicines and 77 (18%) not refilling a prescription because of cost. Sixty-two (15%) households reported significant difficulties with prescription costs. Households with children had twice the odds of reporting significant difficulties than those without (OR= 2.0, 95% CI 1.2-3.5). Of the 442 (43%) GP patients who participated, 25 (6%) patients reported prescription cost as the reason for delaying their visit. Of the 291 patients who received a prescription, 26 (9%) patients reported cost as the reason for not collecting some or all of their prescriptions.

IMPLICATIONS

Given the wide variation in patients' capacity to manage increased out-of-pocket costs, co-payments may add to patients' burden and place a potential barrier to safe and timely prescription use.

Particle trajectories in linear periodic capillary and capillary-gravity water waves

Surface tension plays a significant role as a restoration force in the setting of small-amplitude waves, leading to pure capillary and gravity-capillary waves. We show that within the framework of linear theory, the particle paths in a periodic gravity-capillary or pure capillary wave propagating at the surface of water over a flat bed are not closed.

Multiple flow transitions in a box heated from the side in low-Prandtl-number fluids

The determination of the flow transitions in a cavity heated from the side in low-Prandtl-number fluids has been a challenge for many years. Contrarily to the Rayleigh-Bénard situation, these transitions occur in already very intense convective flows, and the problem has been up to now mainly treated in two-dimensional situations. Thanks to a performing numerical method, the thresholds corresponding to the first flow transition in a three-dimensional (3D) parallelepipedic cavity have been determined for a wide range of aspect ratios and Prandtl number values. We obtain a kind of map of the transitions involved. Such a map of transitions is quite usual for Rayleigh-Bénard or Marangoni-Bénard situations, but completely new for 3D cavities heated from the side. The most striking result is the very frequent change of stability branches when the aspect ratios or Prandtl number are changed, which indicates different flow structures triggered at the thresholds, either steady or oscillatory, and breaking some of the symmetries of the problem.

Epoetin-alfa initiation at Hb 10–11 or Hb <10 g/dL: Analysis of safety and efficacy

19628

Background: Current guidelines recommend consideration of epoetin alfa (EPO) therapy for chemotherapy-induced anemia (CIA) either when Hb <11 g/dL (National Comprehensive Cancer Network) or when Hb < 10g/dL (ASCO/ASH 2002). The objective was to evaluate the safety and efficacy of EPO in patients (pts) with CIA when EPO was initiated at Hb 10–11 or at <10 g/dL. Methods: A post hoc analysis was performed on data from randomized, well-controlled trials conducted from 2002–2006. Trials in which EPO therapy was initiated at the approved dose of 40,000 Units weekly in male and female pts with Hb <11g/dL and =1 post-baseline Hb value were included. Two trials were identified, T1 and T2. Safety was assessed by the proportion of pts experiencing clinically relevant thrombovascular events (CR- TVEs) who received =1 dose of EPO. Efficacy was assessed by RBC transfusion requirements (Day 1 - end of treatment [EOT] and Day 29 - EOT) and achievement of durable Hb response (Hb =11 g/dL for =2 consecutive weeks). Results: Baseline (BL) characteristics (age, gender, platinum-based therapy, ECOG PS, and tumor type) were similar between the Hb 10–11 and <10 g/dL groups. BL Hb was 10.53 and 9.29 g/dL in T1 and 10.28 and 9.53 g/dL in T2 for the Hb 10–11 and Hb<10 g/dL subsets, respectively. Results are summarized below ( table ). Conclusions: These results show that patients treated with EPO at an Hb of 10–11 g/dL appear to have a lower incidence of CR-TVEs compared to patients treated at Hb <10 g/dL. In addition, patients who started EPO treatment at an Hb of 10–11 g/dL had fewer RBC transfusions and higher durable Hb response. Trial 1 - Waltzman et al. The Oncologist. 2005;10:642–650. Trial 2 - Henry et al. Curr Med Res Opin. 2006;22:1403–1413.

No significant financial relationships to disclose.

[Table: see text]

Randomized study of early intervention compared to standard intervention with darbepoetin-alpha (DA) for chemotherapy-induced anemia (CIA) in early stage breast cancer (ESBC)

19538

Background: Dose dense chemotherapy (DDC) with sequential doxorubicin/ cyclophosphamide followed by paclitaxel Q 14 days has an established place in the treatment of ESBC. However, moderate/severe CIA is a common consequence and therapeutic intervention is frequent. We sought to determine if early intervention at the onset of anemia with DA could reduce the emergence of more severe anemia during therapy and maintain quality of life compared to later intervention. Material and Methods: Non-iron deficient (ferritin > 50) patients (pts) with hemoglobin (Hb) levels >11.0 g/dl scheduled to receive adjuvant or neoadjuvant DDC for ESBC were recruited. Pts were randomly assigned prior to chemotherapy to initiate treatment with DA 200 μg q2w SQ when Hb < 11.5 g/dl (early intervention, EARLY), or DA 200 μg q2w SQ when Hb < 10.0 g/dl (standard intervention, STD) with end of treatment defined as 14 days after the last cycle of chemotherapy. Dose escalation for inadequate response of < 1 g/dl after 6 weeks of DA and dose withholding/reduction for Hb >13 g/dl were pre-specified. Results: The complete sample of 149 pts have been accrued (median age of 53.1, range 28.7 - 74.5). Analysis of fatigue ratings show a trend towards lower fatigue scores in EARLY at Hb nadir, and at end of study,(ANOVA, Group x Time interaction, p=.07). Discussion: Early intervention with DA significantly reduces the risk of developing moderate/severe CIA and increases time spent in the target range during DDC for ESBC.

[Table: see text]

No significant financial relationships to disclose.

Cyclooxygenase-2 inhibitors and coronary occlusion--exploring dose-response relationships

AIMS

To investigate the relationship between acute coronary syndrome (ACS) and ingested doses of selective cyclooxygenase-2 (COX-2) inhibitors and other nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

Case-control study, commenced August 2003. Cases were patients admitted to hospital with ACS (myocardial infarction/unstable angina). Controls were hospital patients admitted for reasons other than acute vascular ischaemia or conditions that are believed to be complications of treatment with COX-2 inhibitors or NSAIDs. Structured interviews were undertaken within 7 days of admission, collecting information on cardiovascular events and risk factors and all ingested drugs, including the doses of COX-2 inhibitors and NSAID consumed in the previous week and month.

RESULTS

An interim analysis of the data was conducted in late 2004 to inform a review of the COX-2 inhibitors by the Australian drug regulatory agency. Between August 2003 and October 2004, we recruited 328 ACS cases and 478 controls. With non-use of COX-2 inhibitors or NSAIDs as the reference the adjusted odds ratios (OR) for ACS were: celecoxib 1.11 (95% confidence interval 0.59, 2.11), rofecoxib 0.63 (0.31, 1.28) and other NSAIDs 0.67 (0.41, 1.09). Among control subjects, median daily ingested doses of celecoxib and rofecoxib were 200 mg and 13.4 mg, respectively. Using these to stratify risk, adjusted ORs for ACS were: 'low' dose (< median) 0.44 (0.19, 1.03); 'high' dose (>/= median) 1.22 (0.67, 2.21). A test for interaction across doses was statistically significant, OR 2.8 (1.0, 7.7), suggesting that at low doses, COX-2 inhibitors may be protective, becoming risk-inducing only at higher doses.

CONCLUSION

The possibility that the gradient of cardiovascular risk with COX-2 inhibitors runs from protective to risk-inducing has biological plausibility and merits further investigation.

A randomized, double-blind study of pegylated liposomal doxorubicin for the treatment of AIDS-related Kaposi's sarcoma

BACKGROUND

Despite a decreased incidence of AIDS-related Kaposi's sarcoma (KS) due to the advent of highly active antiretroviral therapy, approximately 15% of AIDS patients still develop AIDS-related KS. This study evaluated the clinical benefit, tumor response, and safety of pegylated liposomal doxorubicin for the treatment of AIDS-related KS.

METHODS

This was a double-blind, multicenter study that randomized patients with AIDS-related KS to six cycles of pegylated liposomal doxorubicin (20 mg/m2; n = 60) or liposomal daunorubicin (40 mg/m2; n = 19) every 2 weeks. Clinical benefit was assessed using patient questionnaires and monitoring of KS-associated symptoms. Tumor responses were assessed using imaging techniques, direct measurement of skin lesions, and photographs, when possible.

RESULTS

Clinical benefit was observed in 48/60 patients (80%) receiving pegylated liposomal doxorubicin and was maintained for a median of 62 days (range, 28-107 days). Clinical benefit was achieved by 12/19 patients (63.2%) receiving liposomal daunorubicin and was maintained for a median of 55 days (range, 28-84 +days). Clinical benefit correlated with tumor response. Tumor responses were achieved by 55.0% of patients receiving pegylated liposomal doxorubicin and 31.6% of patients receiving liposomal daunorubicin. Response rates were similar within each treatment group when only those patients without changes in antiretroviral therapy during treatment were considered. Adverse events associated with pegylated liposomal doxorubicin were neutropenia (30%), nausea (28.3%), and asthenia (16.7%).

CONCLUSIONS

Pegylated liposomal doxorubicin is safe and effective for the treatment of AIDS-related KS, with most patients experiencing clinical benefit, tumor response, or both.

Rapamycin is efficacious against primary effusion lymphoma (PEL) cell lines in vivo by inhibiting autocrine signaling

The antitumor potency of the mTOR inhibitor rapamycin (sirolimus) is the subject of intense investigations. Primary effusion lymphoma (PEL) appears as an AIDS-defining lymphoma and like Kaposi sarcoma has been linked to Kaposi sarcoma-associated herpesvirus (KSHV). We find that (1) rapamycin is efficacious against PEL in culture and in a murine xenograft model; (2) mTOR, its activator Akt, and its target p70S6 kinase are phosphorylated in PEL; (3) rapamycin inhibits mTOR signaling as determined by S6 phosphorylation; (4) KSHV transcription is unaffected; (5) inhibition of IL-10 signaling correlates with drug sensitivity; and (6) addition of exogenous IL-10 or IL-6 can reverse the rapamycin growth arrest. This validates sirolimus as a new treatment option for PEL.

What drives health-care spending priorities? An international survey of health-care professionals

The authors set out to compare spending priorities for health care, across a selection of largely middle-income countries, through a survey of current and future decision makers.

Cardiovascular risk and inhibition of cyclooxygenase: a systematic review of the observational studies of selective and nonselective inhibitors of cyclooxygenase 2

CONTEXT

Evidence that rofecoxib increases the risk of myocardial infarction has led to scrutiny of other nonsteroidal anti-inflammatory drugs (NSAIDs). Regulatory agencies have provided variable advice regarding the cardiovascular risks with older nonselective NSAIDs.

OBJECTIVE

To undertake a systematic review and meta-analysis of controlled observational studies to compare the risks of serious cardiovascular events with individual NSAIDs and cyclooxygenase 2 inhibitors.

DATA SOURCES

Searches were conducted of electronic databases (1985-2006), scientific meeting proceedings, epidemiological research Web sites, and bibliographies of eligible studies.

STUDY SELECTION

Eligible studies were of case-control or cohort design, reported on cardiovascular events (predominantly myocardial infarction) with cyclooxygenase 2 inhibitor, NSAID use, or both with nonuse/remote use of the drugs as the reference exposure. Of 7086 potentially eligible titles, 17 case-control and 6 cohort studies were included. Thirteen studies reported on cyclooxygenase 2 inhibitors, 23 on NSAIDs, and 13 on both groups of drugs.

DATA EXTRACTION

Two people independently extracted data and assessed study quality with disagreements resolved by consensus.

DATA SYNTHESIS

Data were combined using a random-effects model. A dose-related risk was evident with rofecoxib, summary relative risk with 25 mg/d or less, 1.33 (95% confidence interval [CI], 1.00-1.79) and 2.19 (95% CI, 1.64-2.91) with more than 25 mg/d. The risk was elevated during the first month of treatment. Celecoxib was not associated with an elevated risk of vascular occlusion, summary relative risk 1.06 (95% CI, 0.91-1.23). Among older nonselective drugs, diclofenac had the highest risk with a summary relative risk of 1.40 (95% CI, 1.16-1.70). The other drugs had summary relative risks close to 1: naproxen, 0.97 (95% CI, 0.87-1.07); piroxicam, 1.06 (95% CI, 0.70-1.59); and ibuprofen, 1.07 (95% CI, 0.97-1.18).

CONCLUSIONS

This review confirms the findings from randomized trials regarding the risk of cardiovascular events with rofecoxib and suggests that celecoxib in commonly used doses may not increase the risk, contradicts claims of a protective effect of naproxen, and raises serious questions about the safety of diclofenac, an older drug.

The mechanism of human angiosarcoma drug resistance

9567

Background: Angiosarcoma (AS) is a malignant neoplasm of endothelial cells. AS has an extremely poor outcome since it can metastasize widely and rapidly becomes chemoresistant. Understanding the mechanism of this resistance is important not only because of the critical need for new therapeutic strategies in sarcoma, but also since it sheds light on important pathways in endothelial growth that may help understand tumor angiogenesis. Methods/Results: We have established and characterized stable pre-chemotherapy (named B8) and chemotherapy-resistant (named D3) angiosarcoma cell lines from an individual patient with primary (non radiated) breast angiosarcoma prior to initiation of chemotherapy and later after development of resistance to adriamycin, ifosfamide, gemcitabine, docetaxel, paclitaxel, interferon, thalidomide and bevacizumab. D3 cells differ dramatically from B8s in morphology and function. Prechemotherapy B8 cells assume a polygonal morphology reminiscent of native endothelial cells, the D3 cells throw out long processes that span several cell lengths, and do not appear to contact-inhibit. Migration and invasion assays confirm the highly motile nature of these cells. Although it is not surprising that the D3 cells were doxorubicin resistant, we found that unlike the B8 cells, the D3 cells actively transcribe VEGF. In keeping with this, D3 cells are relatively more sensitive to growth inhibition by the anti-VEGF drug bevacizumab than chemonaïve B8 cells. Conclusion: These studies reveal two avenues to target chemoresistant human angiosarcoma; via agents affecting cell migration and those agents that target the VEGF pathway.

No significant financial relationships to disclose.

Darbepoetin alfa administered at varying intervals compared with weekly epoetin alfa for treating chemotherapy-induced anemia: A pooled analysis of 20 clinical trials

18508

Background: Cancer patients (pts) often develop chemotherapy-induced anemia (CIA), resulting in an increased risk for transfusions and fatigue. The erythropoiesis-stimulating agents (ESAs) epoetin alfa (EA) and darbepoetin alfa (DA) can reduce transfusion requirements, raise hemoglobin (Hb) levels, and decrease fatigue in pts with CIA. The 74-hour half-life of DA allows for flexible dosing with weekly (QW), every-2-week (Q2W), or every-3-week (Q3W) administration. This study evaluated if the dosing interval used to administer DA affected its efficacy. Methods: Data from 20 clinical trials in the CIA setting were pooled, including single-arm, active-controlled, and placebo-controlled trials (a full description of these studies will be presented). Six studies contributed data for DA QW, 7 studies for DA Q2W, and 5 studies for DA Q3W. Controlled studies used either a placebo or EA as the comparator. Logistic regression with treatment as a random effect was used to analyze the clinical trials. Endpoints included the percentage of pts requiring transfusions (from week 1 to end of the treatment period [EOTP] and from week 5 to EOTP), reaching a target Hb of ≥ 11 g/dL, and achieving ≥ 3 point change in FACT-F score from baseline (BL). Percentages were adjusted for BL Hb levels (< 10 vs ≥ 10 g/dL), whether pts received platinum chemotherapy (no vs yes), and for dosage adjustments. Results: The type of ESA used (EA or DA) did not appear to affect the percentage of study pts who achieved clinically meaningful endpoints (see Table ). The results from these analyses also suggest that the dosing interval at which DA was administered did not affect its efficacy in study pts (see Table ). Conclusions: DA administered at dosing intervals of QW, Q2W, or Q3W has comparable efficacy to EA QW. This flexibility allows DA administration to be synchronized with common chemotherapy schedules, which may increase pt convenience by reducing the number of clinic visits.

[Table: see text]

[Table: see text]

Phase II trial of nanoparticle albumin-bound paclitaxel (ABX) + capecitabine (XEL) in first line treatment of metastatic breast cancer (MBC)

10731

Background: ABX and XEL both have substantial single agent activity in MBC. Taxane and anti-metabolic doublets improve response rate and TTP compared to singlet therapy. ABX given weekly has excellent safety and efficacy profile with maintenance of dose intensity. We designed this study to test the safety and efficacy of ABX + XEL given in a novel combination schedule. Methods: This phase II, multicenter open label study utilized ABX 125 mg/m2 IV on day 1, 8 and with no premeds and Xeloda 825 mg/m2 PO days 1–14 every three weeks. Entry criteria include measurable MBC by RECIST, no prior chemo for metastatic disease, > 6 months since adjuvant fluoropyrimidine and paclitaxel. A total of 50 patients (pts) are scheduled to be enrolled. Primary endpoint is objective response rate. Results: To date, 14 patients have entered on study. Safety analysis prespecified by the protocol is completed in the 1st six patients. No unique, unexpected or grade 4 toxicities have occurred. Two patients have grade 3 hand-foot syndrome, one had grade 3 neutropenia and one had grade 3 fatigue. Enrollment is continuing without change in dose/schedule. Response data is available in the first two cycles of therapy in 8 patients. At this point, two pts have achieved PR, four have stable disease and two have progressive disease. Conclusions: The combination of weekly ABX plus daily XEL orally at clinically effective doses is safe and shows preliminary evidence of efficacy. Complete enrollment of this trial is expected by May 2006 and updated results will be presented.

[Table: see text]

The utility of PET scanning in the management of squamous cell carcinoma of the anus

4152

Background: PET scanning is an established modality that is useful in the clinical management of squamous cell carcinoma (SCC) of the head and neck and esophagus. This study evaluates the usefulness of PET scans in the management of anal SCC. Methods: Prospective case series of all patients treated for SCC of the anus between 2002 and 2006 in a multi-disciplinary oncology practice group. All patients had staging studies at diagnosis of anal SCC that included CT scan of the chest/abdomen/pelvis and PET scan. All patients with palpable inguinal adenopathy or PET scans positive for inguinal adenopathy underwent fine needle aspiration (FNA) of inguinal nodes. All patients were evaluated by physical exam (PE) and biopsy (Bx), when appropriate, within 3 months of completing treatment. All patients who completed combined chemoradiation for anal SCC and had a post-treatment PET scan were included in this study. Results: 14 of 20 treated patients met criteria for this study. Sensitivity of pre-treatment PET scan was 100% for primary tumor. Extra-pelvic sites with PET SUV<4.0 were uniformly negative for tumor. 66% of inguinal nodes identified by PET scan were FNA positive for metastatic disease. Post-treatment, combined PE and Bx accurately predicted presence or absence of disease in 93%. Post-treatment scans were obtained a mean of 7.6 months after chemoradiation (range 1 to 42 months). In these patients, PET scan sensitivity = 50%, specificity = 72%, predictive value positive (PVP) = 50%, predictive value negative = 80%. 64% of scans were performed within 6 months of treatment; in these, PVP = 33% and PVN = 66%. Conclusions: PET scanning for anal SCC provides accurate staging of disease at presentation and may alter treatment planning by identifying inguinal node involvement not apparent on clinical examination. In this series, PET scan results did not change post-chemoradiation management in any case. Importantly, resolution of primary tumor defined by PET scan was accurate only 80% of the time. PE and Bx within 3 months of treatment were more accurate than PET scan in assessing disease. Post-treatment evaluation of anal SCC should continue to include careful PE, CT scan and Bx when appropriate.

No significant financial relationships to disclose.

The fight against disease mongering: generating knowledge for action

The Guest Editors of the Disease Mongering theme issue argue that we need better research to identify, understand, and combat the threat to human health from the corporate-sponsored selling of sickness.

Family violence

Family violence occurs in many forms; the most prominent are domestic violence, child abuse, and elder abuse. Family violence affects many persons at some point in their life and constitutes the majority of violent acts in our society. Although there has been considerable study of the patterns, risk factors, and interventions for each form of family violence, great controversy still exists within each area. There is growing recognition of an overlap in the patterns, causes, and effective interventions across types of family violence. There is also an increasing awareness of the value of greater integration of theory and research across areas into a family violence approach through an ecological perspective. This review focuses on current knowledge related to these problems and suggests integrative steps to advance knowledge.