Digital breast tomosynthesis: sensitivity for cancer in younger symptomatic women.

OBJECTIVE: Full-field digital mammography (FFDM) has limited sensitivity for cancer in younger women with denser breasts. Digital breast tomosynthesis (DBT) can reduce the risk of cancer being obscured by overlying tissue. The primary study aim was to compare the sensitivity of FFDM, DBT and FFDM-plus-DBT in women under 60 years old with clinical suspicion of breast cancer. METHODS: This multicentre study recruited 446 patients from UK breast clinics. Participants underwent both standard FFDM and DBT. A blinded retrospective multireader study involving 12 readers and 300 mammograms (152 malignant and 148 benign cases) was conducted. RESULTS: Sensitivity for cancer was 86.6% with FFDM [95% CI (85.2-88.0%)], 89.1% with DBT [95% CI (88.2-90%)], and 91.7% with FFDM+DBT [95% CI (90.7-92.6%)]. In the densest breasts, the maximum sensitivity increment with FFDM +DBT over FFDM alone was 10.3%, varying by density measurement method. Overall specificity was 81.4% with FFDM [95% CI (80.5-82.3%)], 84.6% with DBT [95% CI (83.9-85.3%)], and 79.6% with FFDM +DBT [95% CI (79.0-80.2%)]. No differences were detected in accuracy of tumour measurement in unifocal cases. CONCLUSIONS: Where available, DBT merits first-line use in the under 60 age group in symptomatic breast clinics, particularly in women known to have very dense breasts. ADVANCES IN KNOWLEDGE: This study is one of very few to address the accuracy of DBT in symptomatic rather than screening patients. It quantifies the diagnostic gains of DBT in direct comparison with standard digital mammography, supporting informed decisions on appropriate use of DBT in this population.

The requirement for carotenoids in the assembly and function of the photosynthetic complexes in Chlamydomonas reinhardtii.

We have investigated the importance of carotenoids on the accumulation and function of the photosynthetic apparatus using a mutant of the green alga Chlamydomonas reinhardtii lacking carotenoids. The FN68 mutant is deficient in phytoene synthase, the first enzyme of the carotenoid biosynthesis pathway, and therefore is unable to synthesize any carotenes and xanthophylls. We find that FN68 is unable to accumulate the light-harvesting complexes associated with both photosystems as well as the RC subunits of photosystem II. The accumulation of the cytochrome b6f complex is also strongly reduced to a level approximately 10% that of the wild type. However, the residual fraction of assembled cytochrome b6f complexes exhibits single-turnover electron transfer kinetics comparable to those observed in the wild-type strain. Surprisingly, photosystem I is assembled to significant levels in the absence of carotenoids in FN68 and possesses functional properties that are very similar to those of the wild-type complex.

Anti-angiogenic therapy using thalidomide combined with chemotherapy in small cell lung cancer: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Cancer cells rely on angiogenesis for growth and dissemination, and small cell lung cancer (SCLC) is a highly angiogenic tumor. We evaluated thalidomide, an anti-angiogenic agent, when combined with chemotherapy and as maintenance treatment. METHODS: A total of 724 patients (51% with limited and 49% with extensive disease) were randomly assigned to receive placebo or thalidomide capsules, 100-200 mg daily for up to 2 years. All patients received etoposide and carboplatin every 3 weeks for up to six cycles. Endpoints were overall survival, progression-free survival, tumor response rate, toxicity, and quality of life (QoL). Hazard ratios (HRs) for comparing thalidomide against placebo were estimated using Cox regression modeling. Statistical tests were two-sided. RESULTS: The median overall survival was 10.5 months (placebo) and 10.1 months (thalidomide) (HR for death = 1.09, 95% confidence interval [CI] = 0.93 to 1.27; P = .28). Among patients with limited-stage disease, there was no evidence of a survival difference (HR for death = 0.91, 95% CI = 0.73 to 1.15), but among patients with extensive disease, survival was worse in the thalidomide group (HR for death = 1.36, 95% CI = 1.10 to 1.68). Progression-free survival rates were also similar in the two groups (HR = 1.07, 95% CI = 0.92 to 1.24). Thalidomide was associated with an increased risk of having a thrombotic event, mainly pulmonary embolus and deep vein thrombosis (19% thalidomide vs 10% placebo; HR = 2.13, 95% CI = 1.41 to 3.20; P < .001). There were no statistically significant differences between treatments in hematological and nonhematological toxic effects, except more patients in the thalidomide group had rash, constipation, or neuropathy. Overall, QoL scores were similar in the two treatment groups, but thalidomide was associated with less insomnia and diarrhea and more constipation and peripheral neuropathy. CONCLUSIONS: In this large randomized trial, thalidomide in combination with chemotherapy did not improve survival of patients with SCLC but was associated with an increased risk of thrombotic events.

Bidirectional electron transfer in photosystem I: replacement of the symmetry-breaking tryptophan close to the PsaB-bound phylloquinone A1B with a glycine residue alters the redox properties of A1B and blocks forward electron transfer at cryogenic temperatures.

A conserved tryptophan residue located between the A(1B) and F(X) redox centres on the PsaB side of the Photosystem I reaction centre has been mutated to a glycine in Chlamydomonas reinhardtii, thereby matching the conserved residue found in the equivalent position on the PsaA side. This mutant (PsaB:W669G) was studied using EPR spectroscopy with a view to understanding the molecular basis of the reported kinetic differences in forward electron transfer from the A(1A) and the A(1B) phyllo(semi)quinones. The kinetics of A(1)(-) reoxidation due to forward electron transfer or charge recombination were measured by electron spin echo spectroscopy at 265 K and 100 K, respectively. At 265 K, the reoxidation kinetics are considerably lengthened in the mutant in comparison to the wild-type. Under conditions in which F(X) is initially oxidised the kinetics of charge recombination at 100 K are found to be biphasic in the mutant while they are substantially monophasic in the wild-type. Pre-reduction of F(X) leads to biphasic kinetics in the wild-type, but does not alter the already biphasic kinetic properties of the PsaB:W669G mutant. Reduction of the [4Fe-4S] clusters F(A) and F(B) by illumination at 15 K is suppressed in the mutant. The results provide further support for the bi-directional model of electron transfer in Photosystem I of C. reinhardtii, and indicate that the replacement of the tryptophan residue with glycine mainly affects the redox properties of the PsaB bound phylloquinone A(1B).