Efficiency and spectrum enhancement in a tapered free-electron laser amplifier

We report the first experimental characterization of efficiency and spectrum enhancement in a laser-seeded free-electron laser using a tapered undulator. Output and spectra in the fundamental and third harmonic were measured versus distance for uniform and tapered undulators. With a 4% field taper over 3 m, a 300% (50%) increase in the fundamental (third harmonic) output was observed. A significant improvement in the spectra with the elimination of sidebands was observed using a tapered undulator. The experiment is in good agreement with predictions using the MEDUSA simulation code.

Regulation of miRNA expression by Src and contact normalization: effects on nonanchored cell growth and migration

Transformation by the Src tyrosine kinase (Src) promotes nonanchored cell growth and migration. However, nontransformed cells can force Src-transformed cells to assume a normal morphology and phenotype by a process called 'contact normalization'. It has become clear that microRNA (miRNA) can affect tumorigenesis by targeting gene products that direct cell growth and migration. However, the roles of miRNA in Src transformation or contact normalization have not yet been reported. We examined the expression of 95 miRNAs and found 9 of them significantly affected by Src. In this study, we report that miR-218 and miR-224 were most significantly induced by Src, but not affected by contact normalization. In contrast, miR-126 was most significantly suppressed by Src and was induced by contact normalization in transformed cells. Mir-126 targets Crk, a component of the focal adhesion network that participates in events required for tumor cell migration. Accordingly, we show that miR-126 expression correlates inversely with Crk levels, motility and the invasive potential of human mammary carcinoma cells. Moreover, we show that miR-224 expression promotes nonanchored growth of nontransformed cells. These data reveal novel insights into how Src regulates miRNA expression to promote hallmarks of tumor cell growth and invasion, and how nontransformed cells can affect miRNA expression in adjacent tumor cells to inhibit this process.

Lifespan influences on mid- to late-life cognitive function in a Chinese birth cohort

OBJECTIVE

To explore factors throughout the lifespan that influence cognition in midlife to late life.

METHODS

We conducted a retrospective birth cohort study of 2,062 individuals born during 1921-1954 in Beijing, China. In 2003-2005, birth records were abstracted, and participants then 50-82 years old received standardized examinations for health, cognition, and socio-environmental measures. Using cumulative logit models, we assessed adjusted relative effects of prenatal, early life, and adult factors on mid- to late-life cognition.

RESULTS

Most prenatal factors were associated with mid- to late-life cognition in the unadjusted models. However, when childhood and adult factors were sequentially added to the models, the impact of prenatal factors showed successive attenuation in effect size, and became insignificant. In contrast, early life factors remained significantly associated with mid- to late-life cognition even after full life-course adjustments. Specifically, those whose fathers had laborer vs professional occupations (odds ratio [OR](Laborer) 1.74; 95% confidence interval [CI]: 1.25-2.42) had poorer cognitive outcomes, while individuals who drank milk daily in childhood (OR 0.65; 95% CI: 0.54-0.80), had more years of education (OR(10-12 years) 0.60; 95% CI: 0.45-0.81; OR(13+ yrs) 0.29; 95% CI: 0.23-0.38), and were taller adults (OR(height > or = SD) 0.65; 95% CI: 0.49-0.86) had better cognition. The high prenatal risk infants had similar patterns with a trend toward a stronger association between cognition and socioenvironmental factors.

CONCLUSION

Mid- to late-life cognition is influenced by factors over the entire lifespan with the greatest impact coming from early life exposures. Nutrition, education, social, and family environment in early life may have a long-term impact on cognition in developing countries.

Multidrug resistant gram-negative bacilli as predominant bacteremic pathogens in liver transplant recipients

BACKGROUND

Bacteremias, which are often caused by gram-negative bacteria, are the most frequently occurring infectious complications after liver transplantation (LT). The aim of this study was to investigate bacteremic incidence, pathogenic spectrum, risk factors for bacteremia due to multidrug resistant (MDR) gram-negative bacilli, and its impact on mortality after LT.

METHODS

A cohort analysis of prospectively recorded data was done in 475 LT recipients, who were divided into 3 categories: cases with gram-negative bacteremia, cases with MDR gram-negative bacteremia, and cases without bacteremia as controls.

RESULTS

In 475 LT recipients, there were 152 (32.0%) patients with gram-negative bacillus bacteremia in the first 6 months after LT. Out of 152 patients, there were 225 bacteremic episodes, which accounted for 69.7% in a total 323 bacteremic episodes. A total of 190 bacteremic episodes were caused by Stenotrophomonas maltophilia, Enterobacteriaceae, Ochrobactrum anthropi, Pseudomonas, and Acinetobacter baumanii, all of which were the most frequent gram-negative isolates in this study, and MDR bacilli constituted 56.3%. The most frequent source was intravascular catheters. There were 70 patients with MDR gram-negative bacillus bacteremia. Independent risk factors for bacteremia due to MDR gram-negative bacillus were as follows: post-LT abdominal infection (P<0.0001, odds ratio [OR] 0.066, 95% confidence interval [CI] 0.019-0.226), post-LT reoperative episodes (P<0.0001, OR 10.505, 95% CI 3.055-36.121), or one or more episodes of acute rejection (P=0.042, OR 4.457, 95% CI 0.988-20.103). In the first 6 months after LT, MDR gram-negative bacillus bacteremia-related mortality was significantly higher than that due to antibiotic-susceptible bacillus (38.6% vs. 14.6%, P<0.001).

CONCLUSION

Post-LT bacteremias caused by MDR gram-negative bacilli are common, and associated with allograft acute rejection, post-LT reoperation, and abdominal infection. The increasing isolates of MDR gram-negative bacilli pose a great challenge for clinical treatment.

A phase II trial of thalidomide plus tegafur/uracil for patients with advanced/metastatic hepatocellular carcinoma (HCC): Final report

e15533

Background: Thalidomide (T) is an anti-angiogenic agent with modest activity in advanced/metastatic HCC. Tegafur/uracil (UFT) is an oral prodrug of 5-fluorouracil with activity against various gastrointestinal cancers. Metronomic chemotherapy has been shown to have anti-angiogenic and anti-cancer effect in preclinical and clinical models. This study evaluated the efficacy and safety of the combination of T and metronomic UFT as first-line therapy for advanced HCC. Methods: Patients (Pts) with advanced HCC not treatable by surgery or other loco-regional therapies received T 100mg bid and UFT 125mg/m2 (based on tegafur) bid continuously. Treatment was continued in the absence of disease progression or unacceptable toxicity. Primary endpoint was response rate (RR) by RECIST; secondary endpoints were disease control rate (CR+PR+SD), progression-free survival (PFS), overall survival (OS), and safety. Results: Between Jul 2006 and Jul 2008, 43 intent-to-treat pts (M/F 41/2, median age 55) were enrolled. Baseline characteristics were HBsAg(+)/anti-HCV(+)/both(+) /both(-) 31/6/1/7; AJCC stage II/III/IV 2/18/23; BCLC stage B/C 1/42; CLIP score ≤3/4 27/16; portal vein thrombosis 65%; extrahepatic metastasis 58%; prior local treatment 72%. There were 4 PR (9.3%) and 10 SD (23.3%), with a disease control rate of 32.6%. Median OS was 4.6 (95% CI, 3.5–7.3) months and median PFS was 1.9 (95% CI, 1.8–2.6) months. The OS and PFS for pts with CLIP score ≤3 were 7.6 and 2.6 months, respectively. Grade 3 leucopenia developed in 1 (2.3%) pt. The most common treatment-related grade 3 non-hematologic toxicities were somnolence (n=4, 9.3%), GI bleeding (n=3, 7.0%), and elevated transaminase (n=2, 4.7%). No grade 4 toxicities occurred. Conclusions: The combination of T with metronomic UFT is a well-tolerated regimen with moderate activity for advanced HCC, and worth further exploration in pts with CLIP score ≤3.

[Table: see text]

A phase II study of sorafenib in combination with tegafur/uracil (UFT) for Asian patients with advanced hepatocellular carcinoma (HCC)

4589

Background: Sorafenib, a multikinase inhibitor with antiangiogenic activity, has recently been approved for the treatment of unresectable HCC. Combination of sorafenib with metronomic chemotherapy has theoretic advantage in improving antitumor activity without increasing toxicities. UFT (tegafur: uracil = 4:1 in molar ratio), an oral fluoropyrimidine, is active in various gastrointestinal cancers. We conducted a phase II study to evaluate the efficacy and safety of sorafenib plus low-dose UFT in advanced HCC patients (pts). Methods: Pts with histologically or cytologically proven unresectable/metastatic HCC, ECOG PS 0–2, Child-Puch class A, platelets ≥ 100 K/μl, transaminases ≤ 5 × ULN, bilirubin ≤ 3 mg/dl, INR ≤ 2.3 and creatinine ≤ 1.5 × ULN were enrolled. Prior systemic therapy for advanced disease is not allowed. Sorafenib (400 mg bid) and UFT (125 mg/m2 based on tegafur bid) were taken per os continuously. Tumor assessment was performed q8w by RECIST criteria. Primary endpoint is progression-free survival (PFS). Results: Between April 2007 and April 2008, 53 pts were enrolled. Baseline pts characteristics were: M/F, 47/6; median age 57 (range, 31–83); CLIP score 0–3/4, 48/5; extrahepatic spread/macroscopic vascular invasion, 33/30; and HBsAg(+)/anti-HCV(+)/both(+), 38/13/4. 89% of pts were BCLC stage C. Pts received a median of 3.7 (range 0.3- 18.9+) months of treatment. There were 3 (6%) PR and 27 (51%) SD. The median PFS and OS were of 3.7 months (95% C.I., 1.9- 5.5) and 7.4 months (95% C.I., 3.4- 11.4), respectively. Adverse events (AEs) were summarized in Table . Hand-foot skin reaction (HFSR), fatigue, and diarrhea were most common AEs. HFSR was the major AE resulting in dose reduction (19%) or treatment delay (21%). Grade 3/4 neutropenia occurred in 2 pts (4%). Conclusions: Adding metronomic UFT chemotherapy to sorafenib may improve therapeutic efficacy of the latter in pts with advanced HCC. The toxicity profile of the combination is similar to that of sorafenib alone.

[Table: see text]

[Table: see text]

Phase II study of cetuximab plus weekly cisplatin and 24-hour infusion of high-dose 5-fluorouracil and leucovorin for the first-line treatment of advanced gastric cancer

4567

Background: Cisplatin-HDFL regimen, using weekly 24-hour infusions of cisplatin and high-dose 5-fluorouracil (5-FU) and leucovorin, is commonly used in Taiwan for patients with advanced gastric cancer (GC), showing an overall response rate of approximately 60% (95% CI: 45%-76%) [J Clin Oncol (Suppl) 2006; 24(18S): A14063 ]. We have demonstrated that cetuximab is cytotoxic to human GC cells, and has a chemosensitizing effect for cisplatin and 5-FU in GC cells [Proc AACR 2006; 47: A1233]. Methods: All patients had pathologically confirmed metastatic/ recurrent chemonaive GC, at least 1 measurable lesion, a fasting serum triglyceride level > 70 mg/dl, WHO PS 0/1/2, adequate hepatic, renal, and bone marrow functions. Cetuximab 400 mg/m2 was given as 2h infusion, initially (i.e., D1 of cycle 1); and followed by weekly 1h infusion of 250 mg/m2 (i.e., D8, D15, D22 of cycle 1, and D1, D8, D15, D22 of cycle 2). Cisplatin 35 mg/m2 was given as a 24h infusion, admixing with 5-FU 2,000 mg/m2 and leucovorin 300 mg/m2 (HDFL), D1, D8. A 24h infusion of HDFL was given on D15. Cycles were repeated every 28 days, and response evaluation was performed every 2 cycles & at the end of protocol treatment. The primary end-point was confirmed objective response rate (RR) by RECIST. Results: Between Dec. 2005 and Nov. 2008, 35 patients (M:19, F:16) with a median age of 56 (40–74) were enrolled and evaluable for response assessment. The overall RR was 68.6% (51–83%, 95% C.I.) with 1 CR and 23 PRs. Among a total of 269 cycles (median: 7, range: 2 to 22+ cycles) given, Gr3/4 neutropenia, infection, and hepatic toxicity developed in 6.0%, 4.8%, and 0.74% of 269 cycles, respectively. Two patients have developed acute hepatitis B flare-up among seven HBsAg (+) carriers, and were well controlled by lamivudine. Gr1, Gr2, and Gr3 acne- like rashes have developed in 57.1%, 31.4%, 5.7%; and Gr1, Gr2, Gr3 paronychia have developed in 40.0%, 8.6%, and 2.9% of 35 patients, respectively. Median PFS (range: 3 to 22+ months) and median OS (range: 3 to 35+ months) was11.0 and 14.5 months, respectively. Conclusions: Cetuximab plus infusional cisplatin-HDFL is a highly effective regimen with low toxicity and favourable survival in the first-line treatment of advanced GC.

No significant financial relationships to disclose.

Association of chromosome 2q36.1-36.3 and autosomal dominant transmission in ankylosing spondylitis: results of genetic studies across generations of Han Chinese families

Background:

Ankylosing spondylitis (AS) is a chronic, potentially crippling, spondyloarthropathy with strong genetic components affecting approximately 0.3% of the population. Its exact genetic mechanism and mode of transmission, however, remains obscure.

Methods and results:

The authors conducted a genome wide scan on 75 individuals across multiple generations of three Han Chinese families affected with AS. Segregation analysis and pedigree investigation suggested an autosomal dominant inheritance. Pairwise logarithm of odds (LOD) scores were calculated using LINKAGE package for the obtained genotypes. High resolution mapping was then performed based on markers with significant LOD scores. To minimise the number of crossovers in each family, haplotype were constructed and assigned. Two of the pedigrees shared one candidate region for AS on 2q36.1–2q36.3 spanning 6-cM (maximum heterogeneity LOD score of 12.41 at marker D2S2228), while the other showed strong linkage to the HLA-B region.

Conclusions:

This is the first report which proposes one of the new genetic models of autosomal dominant transmission in AS. The breakthrough in the identification of linkage to chromosome 2q36.1–2q36.3 and the HLA-B region highlights the future potential of more comprehensive genetic studies of determinants of disease risk.