1,264 research outputs found

    Observation of sub-natural linewidths for cold atoms in a magneto-optic trap

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    We have studied the absorption of a weak probe beam through cold rubidium atoms in a magneto-optic trap. The absorption spectrum shows two peaks with the smaller peak having linewidth as small as 28% of the natural linewidth. The modification happens because the laser beams used for trapping also drive the atoms coherently between the ground and excited states. This creates ``dressed'' states whose energies are shifted depending on the strength of the drive. Linewidth narrowing occurs due to quantum coherence between the dressed states. The separation of the states increases with laser intensity and detuning, as expected from this model.Comment: 8 pages, 4 figure

    A new Manifestation of Atomic Parity Violation in Cesium: a Chiral Optical Gain induced by linearly polarized 6S-7S Excitation

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    We have detected, by using stimulated emission, an Atomic Parity Violation (APV) in the form of a chiral optical gain of a cesium vapor on the 7S - 6P3/2_{3/2} transition,consecutive to linearly polarized 6S-7S excitation. We demonstrate the validity of this detection method of APV, by presenting a 9% accurate measurement of expected sign and magnitude. We underline several advantages of this entirely new approach in which the cylindrical symmetry of the set-up can be fully exploited. Future measurements at the percent level will provide an important cross-check of an existing more precise result obtained by a different method.Comment: 4 pages, 2 figure

    Variability in conditioned pain modulation predicts response to NSAID treatment in patients with knee osteoarthritis

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    Background: Patients with painful knee osteoarthritis (OA) demonstrate hyperalgesia and altered pain-modulatory responses. While some prior work has demonstrated cross-sectional associations between laboratory and clinical pain measures, it is unknown whether individual variability in quantitative sensory testing (QST) responses at baseline can prospectively predict analgesic treatment responses. Method: Patients with knee OA (n = 35) were compared on QST responses to a demographically-matched pain-free control group (n = 39), after which patients completed a month-long treatment study of diclofenac sodium topical gel (1 %), applied up to 4 times daily. Results: OA patients demonstrated reduced pain thresholds at multiple anatomic sites, as well as reduced conditioned pain modulation (CPM) and enhanced temporal summation of pain. The most pain-sensitive patients tended to report the most intense and neuropathic OA pain. Following diclofenac treatment, the knee OA cohort showed a roughly 30 % improvement in pain, regardless of the presence or absence of neuropathic symptoms. Baseline CPM scores, an index of endogenous pain-inhibitory capacity, were prospectively associated with treatment-related changes in clinical pain. Specifically, participants with higher CPM at baseline (i.e., better functioning endogenous pain-inhibitory systems) showed more reduction in pain at the end of treatment (p < .05). Conclusions: These results support prior findings of amplified pain sensitivity and reduced pain-inhibition in OA patients. Moreover, the moderate to strong associations between laboratory-based measures of pain sensitivity and indices of clinical pain highlight the clinical relevance of QST in this sample. Finally, the prospective association between CPM and diclofenac response suggests that QST-based phenotyping may have utility in explaining inter-patient variability in long-term analgesic treatment outcomes. Trial registration: ClinicalTrials.Gov Identifier: NCT01383954. Registered June 22, 2011

    Safety of selective internal radiation therapy (SIRT) with yttrium-90 microspheres combined with systemic anticancer agents: expert consensus

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    Selective internal radiation therapy (SIRT) with microspheres labelled with the β-emitter yttrium-90 (Y-90) enables targeted delivery of radiation to hepatic tumors. SIRT is primarily used to treat inoperable primary or metastatic liver tumors. Eligible patients have usually been exposed to a variety of systemic anticancer therapies, including cytotoxic agents, targeted biologics, immunotherapy and peptide receptor radionuclide therapy (PRRT). All these treatments have potential interactions with SIRT; however, robust evidence on the safety of these potential combinations is lacking. This paper provides current clinical experiences and expert consensus guidelines for the use of SIRT in combination with the anticancer treatment agents likely to be encountered in clinical practice. It was agreed by the expert panel that precautions need to be taken with certain drugs, but that, in general, systemic therapies do not necessarily have to be stopped to perform SIRT. The authors recommend stopping vascular endothelial growth factor inhibitors 4-6 weeks before SIRT, and restart after the patient has recovered from the procedure. It may also be prudent to stop potent radiosensitizers such as gemcitabine therapy 4 weeks before SIRT, and restart treatment at least 2‒4 weeks later. Data from phase III studies combining SIRT with fluorouracil (5FU) or folinic acid/5FU/oxaliplatin (FOLFOX) suggest that hematological toxicity is more common from the combination than it is from chemotherapy without SIRT. There is no evidence to suggest that chemotherapy increases SIRT-specific gastro-intestinal or liver toxicities

    A Longitudinal Study of the Reliability of Acupuncture Deqi Sensations in Knee Osteoarthritis

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    Deqi is one of the core concepts in acupuncture theory and encompasses a range of sensations. In this study, we used the MGH Acupuncture Sensation Scale (MASS) to measure and assess the reliability of the sensations evoked by acupuncture needle stimulation in a longitudinal clinical trial on knee osteoarthritis (OA) patients. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used as the clinical outcome. Thirty OA patients were randomized into one of three groups (high dose, low dose, and sham acupuncture) for 4 weeks. We found that, compared with sham acupuncture, real acupuncture (combining high and low doses) produced significant improvement in knee pain (P = .025) and function in sport (P = .049). Intraclass correlation analysis showed that patients reliably rated 11 of the 12 acupuncture sensations listed on the MASS and that heaviness was rated most consistently. Overall perceived sensation (MASS Index) (P = .014), ratings of soreness (P = .002), and aching (P = .002) differed significantly across acupuncture groups. Compared to sham acupuncture, real acupuncture reliably evoked stronger deqi sensations and led to better clinical outcomes when measured in a chronic pain population. Our findings highlight the MASS as a useful tool for measuring deqi in acupuncture research

    A phase 1b study of Selumetinib in combination with Cisplatin and Gemcitabine in advanced or metastatic biliary tract cancer: the ABC-04 study

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    BACKGROUND: Combined treatment with cisplatin and gemcitabine (CisGem) is the standard of care for patients with advanced biliary tract cancer (ABC). Selumetinib (AZD6244, ARRY-142886) potently and selectively inhibits MEK1/2, an intracellular kinase and has shown activity in ABC. The objective of the ABC-04 trial was to establish the recommended dose of selumetinib in combination with CisGem in patients with ABC. METHODS: Eligible patients were ≥ 18 years, had histologically or cytologically-confirmed unresectable recurrent or metastatic biliary tract, gallbladder or ampullary carcinoma, WHO performance status 0-2, and adequate major organ function. Patients may have had prior surgery, radiotherapy or adjuvant chemotherapy, but no prior CisGem and no prior chemotherapy for locally advanced or metastatic disease. Patients received cisplatin 25 mg/m(2) plus gemcitabine 1000 mg/m(2) intravenously on days 1 and 8 of a 21-day cycle. Selumetinib capsules were taken daily. Patients received up to 8 cycles of CisGem and could receive selumetinib until disease progression. A dose de-escalation scheme was used to determine the recommended dose of selumetinib. The first dose level was 75 mg bd. Patients were recruited in cohorts of 3 and assessed for dose limiting toxicity (DLT) during the first cycle of treatment. RESULTS: Thirteen patients were recruited, of whom 12 were evaluable for DLT (1 did not start treatment). All evaluable patients received the starting dose of selumetinib 75 mg bd and one patient experienced a DLT (cardiac chest pain). The median number of days selumetinib was taken (adjusted for the number of days of dose interruptions) was 171.5 (IQR: 75.5 to 344). Two patients remained on treatment at 14 and 19 months post registration. There were 3 temporary and 1 permanent interruptions of selumetinib in cycle 1. Eight patients were evaluable for objective response (RECIST v1.1): 3 had a partial response and 5 stable disease. The median PFS was 6.4 months (IQR 5.2 to 13.7). Toxicities related to selumetinib were mostly related to oedema and rash, grade 1-2 and manageable. Pharmacokinetic analysis showed that the AUC(0-t), AUC(0-∞) and Cmax of selumetinib increased by 12, 11 and 30 % respectively when it was administered with CisGem, while Cmax for the N-desmethyl metabolite of selumetinib decreased by 40 %. There was no evidence that the time of Cmax for selumetinib or N-desmethyl metabolite of selumetinib were different when selumetinib was administered alone or with CisGem. CONCLUSION: The recommended dose of selumetinib when combined with CisGem was 75 mg bd. Translational studies are underway to identify biomarkers that may predict outcome (ClinicalTrials.gov identifier: NCT01242605 July 6(th) 2010)

    Clinical and molecular characterization of HER2 amplified-pancreatic cancer

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    &lt;p&gt;Background: Pancreatic cancer is one of the most lethal and molecularly diverse malignancies. Repurposing of therapeutics that target specific molecular mechanisms in different disease types offers potential for rapid improvements in outcome. Although HER2 amplification occurs in pancreatic cancer, it is inadequately characterized to exploit the potential of anti-HER2 therapies.&lt;/p&gt; &lt;p&gt;Methods: HER2 amplification was detected and further analyzed using multiple genomic sequencing approaches. Standardized reference laboratory assays defined HER2 amplification in a large cohort of patients (n = 469) with pancreatic ductal adenocarcinoma (PDAC).&lt;/p&gt; &lt;p&gt;Results: An amplified inversion event (1 MB) was identified at the HER2 locus in a patient with PDAC. Using standardized laboratory assays, we established diagnostic criteria for HER2 amplification in PDAC, and observed a prevalence of 2%. Clinically, HER2- amplified PDAC was characterized by a lack of liver metastases, and a preponderance of lung and brain metastases. Excluding breast and gastric cancer, the incidence of HER2-amplified cancers in the USA is &#62;22,000 per annum.&lt;/p&gt; &lt;p&gt;Conclusions: HER2 amplification occurs in 2% of PDAC, and has distinct features with implications for clinical practice. The molecular heterogeneity of PDAC implies that even an incidence of 2% represents an attractive target for anti-HER2 therapies, as options for PDAC are limited. Recruiting patients based on HER2 amplification, rather than organ of origin, could make trials of anti-HER2 therapies feasible in less common cancer types.&lt;/p&gt

    DETERMINATION OF PHENYLEPHRINE HYDROCHLORIDE IN PHARMACEUTICAL PREPARATIONS USING SPECTROPHOTOMETRIC METHOD

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    Objective: A simple and sensitive spectrophotometric method has been presented for the determination of phenylephrine hydrochloride by coupling reaction with diazotized sulfacetamide sodium. Methods: The method is based on the diazotization reaction of sulfacetamide sodium with sodium nitrite in the presence of hydrochloric acid to form diazonium salt, which is coupled with the drug in alkaline medium to form azo dye, showing absorption maxima at 425 nm. Results: Calibration plot was linear over the concentration range of 2–24 μg/mL and detection limit of 0.278 μg/mL with a correlation coefficient of 0.9929. All different chemical and physical experimental parameters affecting on the development and stability of the colored product were carefully studied. Conclusions: The proposed method was successfully applied to the determination of phenylephrine in nasal drops with good precision and sensitivity

    An individual based computational model of intestinal crypt fission and its application to predicting unrestrictive growth of the intestinal epithelium.

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    Intestinal crypt fission is a homeostatic phenomenon, observable in healthy adult mucosa, but which also plays a pathological role as the main mode of growth of some intestinal polyps. Building on our previous individual based model for the small intestinal crypt and on in vitro cultured intestinal organoids, we here model crypt fission as a budding process based on fluid mechanics at the individual cell level and extrapolated predictions for growth of the intestinal epithelium. Budding was always observed in regions of organoids with abundant Paneth cells. Our data support a model in which buds are biomechanically initiated by single stem cells surrounded by Paneth cells which exhibit greater resistance to viscoelastic deformation, a hypothesis supported by atomic force measurements of single cells. Time intervals between consecutive budding events, as simulated by the model and observed in vitro, were 2.84 and 2.62 days, respectively. Predicted cell dynamics was unaffected within the original crypt which retained its full capability of providing cells to the epithelium throughout fission. Mitotic pressure in simulated primary crypts forced upward migration of buds, which simultaneously grew into new protruding crypts at a rate equal to 1.03 days-1 in simulations and 0.99 days-1 in cultured organoids. Simulated crypts reached their final size in 4.6 days, and required 40 6.2 days to migrate to the top of the primary crypt. The growth of the secondary crypt is independent of its migration along the original crypt. Assuming unrestricted crypt fission and multiple budding events, a maximal growth rate of the intestinal epithelium of 0.10 days-1 43 is predicted and thus approximately 22 days are required for a 10-fold increase of polyp size. These predictions are in agreement with the time reported to develop macroscopic adenomas in mice after loss of Apc in intestinal stem cells
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