Spectral characterization of a supercontinuum source based on nonlinear broadening in an aqueous K2ZnCl4 salt solution.

We report on investigations concerning the shot-to-shot spectral stability properties of a supercontinuum source based on nonlinear processes such as self-phase modulation and optical wave-breaking in a highly concentrated K2ZnCl4 double salt solution. The use of a liquid medium offers both damage resistance and high third-order optical nonlinearity. Approximately 40 µJ pulses spanning a spectral range between 390 and 960 nm were produced with 3.8% RMS energy stability, using infrared input pulses of 500±50 fs FWHM durations and 2.42±0.04 mJ energies with an RMS stability of 2%. The spectral stability was quantified via acquiring single-shot spectra and studying shot-to-shot variation across a spectral range of 200-1100 nm, as well as by considering spectral correlations. The regional spectral correlation variations were indicative of nonlinear processes leading to sideband generation. Spectral stability and efficiency of energy transfer into the supercontinuum were found to weakly improve with increasing driver pulse energy, suggesting that the nonlinear broadening processes are more stable when driven more strongly, or that self-guiding effects in a filament help to stabilize the supercontinuum generation.

Comparative study on the temporal contrast of femtosecond mode-locked laser oscillators.

We have investigated the temporal intensity contrast characteristics from a broad range of mode-locked short-pulse oscillators used for seeding high-power terawatt and petawatt-class laser systems. Saturable absorber (SESAM), Kerr lens (KLM), nonlinear polarization evolution (NPE) in optical fibers and synchronously pumped optical parametric oscillator (OPO) mode-locked sources have been measured using a third-order autocorrelator with up to 1010 dynamic range. We restricted the temporal characterization to features <30 ps about the laser pulse that reflect fundamental mode-locking processes. We find additional nonlinear terms and residual higher-order dispersion limits the performance of KLM and NPE sources up to the 105 contrast level, while >108 contrast was observed from the SESAM and OPO laser pulse trains.

Flat-top picosecond pulses generated by chirped spectral modulation from a Nd:YLF regenerative amplifier for pumping few-cycle optical parametric amplifiers.

In this paper we present an optically synchronized Nd:YLF regenerative amplifier optimized for use as a preamplifier in a few-cycle optical parametric chirped pulse amplification pump laser. In the pump amplification process we employ a combination of spectral modulation and chirping in order to control and optimize the temporal shape of the pulses. We report on a comparative study of two methods for generating near-flat-top or custom real-time variable-shaped pump pulses using either controlled chirp and shaping of the spectrum of the pulses seeding a regenerative amplifier or intracavity spectral filtering to broaden the gain bandwidth of the system. We show that in addition to minimizing gain narrowing and B-integral, the efficiency of the cascaded nonlinear processes of the parametric amplifiers can be increased.

Nurse-led vs. conventional physician-led follow-up for patients with cancer: systematic review.

AIM: This paper is a report of a systematic review of the effectiveness and cost-effectiveness of nurse-led follow-up for patients with cancer. BACKGROUND: As cancer survivorship increases, conventional follow-up puts a major burden on outpatient services. Nurse-led follow-up is a promising alternative. Data sources. Searches were conducted covering a period from inception to February 2007 of 19 electronic databases, seven online trial registries, five conference proceedings reference lists of previous reviews and included studies. REVIEW METHODS: Standard systematic review methodology was used. Comparative studies and economic evaluations of nurse-led vs. physician-led follow-up were eligible. Studies comparing different types of nurse-led follow-up were excluded. Any cancer was considered; any outcome measure included. RESULTS: Four randomised controlled trials were identified, two including cost analyses. There were no statistically significant differences in survival, recurrence or psychological morbidity. One study showed better HRQL measures for nurse-led follow-up, but one showed no difference, two showed a statistically significant difference for patient satisfaction, but two did not. Patients with lung cancer were more satisfied with nurse-led telephone follow-up and more were able to die at home. Patients with breast cancer thought patient-initiated follow-up convenient, but found conventional follow-up more reassuring. One study showed the cost of nurse-led follow-up to be less than that of physician-led follow-up, but no statistical comparison was made. CONCLUSION: Patients appeared satisfied with nurse-led follow-up. Patient-initiated or telephone follow-up could be practical alternatives to conventional care. However, well-conducted research is needed before equivalence to physician-led follow-up can be assured in terms of survival, recurrence, patient well-being and cost-effectiveness.

Antibacterial prophylaxis after chemotherapy for solid tumors and lymphomas.

BACKGROUND: The role of prophylactic antibacterial agents after chemotherapy remains controversial. METHODS: We conducted a randomized, double-blind, placebo-controlled trial in patients who were receiving cyclic chemotherapy for solid tumors or lymphoma and who were at risk for temporary, severe neutropenia (fewer than 500 neutrophils per cubic millimeter). Patients were randomly assigned to receive either 500 mg of levofloxacin once daily or matching placebo for seven days during the expected neutropenic period. The primary outcome was the incidence of clinically documented febrile episodes (temperature of more than 38 degrees C) attributed to infection. Secondary outcomes included the incidence of all probable infections, severe infections, and hospitalization but did not include a systematic evaluation of antibacterial resistance. RESULTS: A total of 1565 patients underwent randomization (784 to placebo and 781 to levofloxacin). The tumors included breast cancer (35.4 percent), lung cancer (22.5 percent), testicular cancer (14.4 percent), and lymphoma (12.8 percent). During the first cycle of chemotherapy, 3.5 percent of patients in the levofloxacin group had at least one febrile episode, as compared with 7.9 percent in the placebo group (P<0.001). During the entire chemotherapy course, 10.8 percent of patients in the levofloxacin group had at least one febrile episode, as compared with 15.2 percent of patients in the placebo group (P=0.01); the respective rates of probable infection were 34.2 percent and 41.5 percent (P=0.004). Hospitalization was required for the treatment of infection in 15.7 percent of patients in the levofloxacin group and 21.6 percent of patients in the placebo group (P=0.004). The respective rate of severe infection was 1.0 percent and 2.0 percent (P=0.15), with four infection-related deaths in each group. An organism was isolated in 9.2 percent of probable infections. CONCLUSIONS: Among patients receiving chemotherapy for solid tumors or lymphoma, the prophylactic use of levofloxacin reduces the incidence of fever, probable infection, and hospitalization.

Trial of Optimal Personalised Care After Treatment for Gynaecological cancer (TOPCAT-G): a study protocol for a randomised feasibility trial.

BACKGROUND: Gynaecological cancers are diagnosed in over 1000 women in Wales every year. We estimate that this is costing the National Health Service (NHS) in excess of £1 million per annum for routine follow-up appointments alone. Follow-up care is not evidence-based, and there are no definitive guidelines from The National Institute for Health and Care Excellence (NICE) for the type of follow-up that should be delivered. Standard care is to provide a regular medical review of the patient in a hospital-based outpatient clinic for a minimum of 5 years. This study is to evaluate the feasibility of a proposed alternative where the patients are delivered a specialist nurse-led telephone intervention known as Optimal Personalised Care After Treatment for Gynaecological cancer (OPCAT-G), which comprised of a protocol-based patient education, patient empowerment and structured needs assessment. METHODS: The study will recruit female patients who have completed treatment for cervical, endometrial, epithelial ovarian or vulval cancer within the previous 3 months in Betsi Cadwaladr University Health Board (BCUHB) in North Wales. Following recruitment, participants will be randomised to one of two arms in the trial (standard care or OPCAT-G intervention). The primary outcomes for the trial are patient recruitment and attrition rates, and the secondary outcomes are quality of life, health status and capability, using the EORTC QLQ-C30, EQ-5D-3L and ICECAP-A measures. Additionally, a client service receipt inventory (CSRI) will be collected in order to pilot an economic evaluation. DISCUSSION: The results from this feasibility study will be used to inform a fully powered randomised controlled trial to evaluate the difference between standard care and the OPCAT-G intervention. TRIAL REGISTRATION: ISRCTN45565436.

A novel cohort of cancer-testis biomarker genes revealed through meta-analysis of clinical data sets.

The identification of cancer-specific biomolecules is of fundamental importance to the development of diagnostic and/or prognostic markers, which may also serve as therapeutic targets. Some antigenic proteins are only normally present in male gametogenic tissues in the testis and not in normal somatic cells. When these proteins are aberrantly produced in cancer they are referred to as cancer/testis (CT) antigens (CTAs). Some CTA genes have been proven to encode immunogenic proteins that have been used as successful immunotherapy targets for various forms of cancer and have been implicated as drug targets. Here, a targeted in silico analysis of cancer expressed sequence tag (EST) data sets resulted in the identification of a significant number of novel CT genes. The expression profiles of these genes were validated in a range of normal and cancerous cell types. Subsequent meta-analysis of gene expression microarray data sets demonstrates that these genes are clinically relevant as cancer-specific biomarkers, which could pave the way for the discovery of new therapies and/or diagnostic/prognostic monitoring technologies.

Meta-analysis of clinical data using human meiotic genes identifies a novel cohort of highly restricted cancer-specific marker genes.

Identifying cancer-specific biomarkers represents an ongoing challenge to the development of novel cancer diagnostic, prognostic and therapeutic strategies. Cancer/testis (CT) genes are an important gene family with expression tightly restricted to the testis in normal individuals but which can also be activated in cancers. Here we develop a pipeline to identify new CT genes. We analysed and validated expression profiles of human meiotic genes in normal and cancerous tissue followed by meta-analyses of clinical data sets from a range of tumour types resulting in the identification of a large cohort of highly specific cancer biomarker genes, including the recombination hot spot activator PRDM9 and the meiotic cohesin genes SMC1beta and RAD21L. These genes not only provide excellent cancer biomarkers for diagnostics and prognostics, but may serve as oncogenes and have excellent drug targeting potential.

Follow-up of cancer in primary care versus secondary care: systematic review.

BACKGROUND: Cancer follow-up has traditionally been undertaken in secondary care, but there are increasing calls to deliver it in primary care. AIM: To compare the effectiveness and cost-effectiveness of primary versus secondary care follow-up of cancer patients, determine the effectiveness of the integration of primary care in routine hospital follow-up, and evaluate the impact of patient-initiated follow-up on primary care. DESIGN OF STUDY: Systematic review. SETTING: Primary and secondary care settings. METHOD: A search was carried out of 19 electronic databases, online trial registries, conference proceedings, and bibliographies of included studies. The review included comparative studies or economic evaluations of primary versus secondary care follow-up, hospital follow-up with formal primary care involvement versus conventional hospital follow-up, and hospital follow-up versus patient-initiated or minimal follow-up if the study reported the impact on primary care. RESULTS: There was no statistically significant difference for patient wellbeing, recurrence rate, survival, recurrence-related serious clinical events, diagnostic delay, or patient satisfaction. GP-led breast cancer follow-up was cheaper than hospital follow-up. Intensified primary health care resulted in increased home-care nurse contact, and improved discharge summary led to increased GP contact. Evaluation of patient-initiated or minimal follow-up found no statistically significant impact on the number of GP consultations or cancer-related referrals. CONCLUSION: Weak evidence suggests that breast cancer follow-up in primary care is effective. Interventions improving communication between primary and secondary care could lead to greater GP involvement. Discontinuation of formal follow-up may not increase GP workload. However, the quality of the data in general was poor, and no firm conclusions can be reached.

Patients' and healthcare professionals' views of cancer follow-up: systematic review.

BACKGROUND: Cancer follow-up places a significant burden on hospital outpatient clinics. There are increasing calls to develop alternative models of provision. AIM: To undertake a systematic review of qualitative studies examining patients' and healthcare professionals' views about cancer follow-up. DESIGN OF STUDY: Systematic review. SETTING: Primary and secondary care. METHOD: Comprehensive literature searches included: 19 electronic databases, online trial registries, conference proceedings, and bibliographies of included studies. Eligible studies included qualitative studies examining patients' and healthcare professionals' views of cancer follow-up. Studies of patients with any type of cancer, considered free of active disease, or no longer receiving active treatment were included. Findings were synthesised using thematic analysis. RESULTS: Nineteen studies were included; seven were linked to randomised controlled trials. Eight studies examined the views of healthcare professionals (four of which included GPs) and 16 examined the views of patients. Twelve descriptive themes were identified, from which 12 perceived implications for practice were derived. Most themes related to conventional follow-up in secondary care. Some views concerning other models of care were based on participants' ideas, rather than experiences. CONCLUSION: Patients' main concern is recurrent disease, and they find regular follow-up, expertise of specialists, and quick access to tests reassuring. Information regarding the effectiveness of follow-up is not given to patients who also have unmet information needs, which would help them to cope and be more involved. Continuity of care, unhurried consultations, and psychosocial support are important, but sometimes lacking in secondary care. GPs are thought to be unwilling and to have insufficient time and expertise to conduct follow-up.

Testicular cancer: seminoma.

INTRODUCTION: More than half of painless solid swellings of the body of the testis are malignant, with a peak incidence in men aged 25-35 years. About half of testicular cancers are seminomas, which tend to affect older men and have a good prognosis. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in men with stage 1 seminoma (confined to testis) who have undergone orchidectomy? What are the effects of treatments in men with good-prognosis non-stage 1 seminoma who have undergone orchidectomy? What are the effects of maintenance chemotherapy in men in remission after orchidectomy and chemotherapy for good-prognosis non-stage 1 seminoma? What are the effects of treatments in men with intermediate-prognosis seminoma who have undergone orchidectomy? We searched: Medline, Embase, The Cochrane Library and other important databases up to April 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). RESULTS: We found 27 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. CONCLUSIONS: In this systematic review we present information relating to the effectiveness and safety of the following interventions: adjuvant irradiation (20 Gy in 10 fractions to paraaortic area, 30 Gy in 15 fractions to paraaortic area and iliac nodes), chemotherapy (maintenance, adjuvant, single-agent carboplatin, three or four cycles, different number of cycles of adjuvant, using bleomycin added to vinblastine plus cisplatin, using etoposide plus cisplatin with or without bleomycin, adding higher doses to a two-drug chemotherapy regimen using cisplatin or vinblastine), radiotherapy (adjuvant, different drug combinations, 30-36 Gy in 15-18 fractions), surveillance.