On the relative roles of higher-order nonlinearity and ionization in ultrafast light-matter interactions

Far off-resonant ultrafast and nonlinear light-matter interactions are studied using a one-dimensional atomic model. Results from a pump-probe diagnostic reveal that any higher-order nonlinear refraction is masked by ionization-induced defocusing before it becomes significant. On the other hand, we show that signatures of a higher-order nonlinearity may still be manifest via low-order harmonics of the pump center frequency. Implications for filamentation of femtosecond pulses are pointed out.

Abstract 68: Reducing Hepatic Very-Low-Density Lipoprotein Production by Knockdown of Microsomal Triglyceride Transfer Protein Decreases Transintestinal Cholesterol Excretion

Atherosclerotic coronary vascular disease (ASCVD) remains the number one killer of Americans. A way to reduce the low-density lipoprotein cholesterol (LDLc), the primary risk factor of ASCVD, is to increase cholesterol excretion from the body. Our group and others have recently found that cholesterol excretion can be facilitated by both biliary and non-biliary pathways. The lipoprotein that delivers cholesterol from the liver through the plasma to the small intestine (SI) for transintestinal cholesterol excretion (TICE) is not yet known. We hypothesized that cholesterol leaves the liver via very low-density lipoproteins (VLDL) for TICE. We assessed this hypothesis by using antisense oligonucleotides (ASO) to knockdown hepatic expression of microsomal triglyceride transfer protein (MTP), which is necessary for VLDL assembly. While maintained on a high cholesterol (0.2% wt/wt) diet for six weeks, wild type (WT) mice and hepatic Niemann-Pick C1-like 1 transgenic mice (L1Tg), which predominantly excrete cholesterol via TICE, were treated with control ASO or MTP ASO. In both WT and L1Tg mice, MTP ASO decreased hepatic MTP protein expression by 60% and increased hepatic total cholesterol concentration 3.5 fold. Regardless of treatment with control or MTP ASO, L1Tg mice had an 80% reduction in biliary cholesterol compared to WT mice. However, L1Tg mice treated with MTP ASO displayed a 60% reduction in fecal neutral sterol (FNS) excretion. In summary our data show that when VLDL production is decreased in mice with reduced biliary cholesterol secretion capacity, FNS excretion is impaired. These data support our conclusion that cholesterol leaves the liver through VLDL for TICE.

New test of local Lorentz invariance using a 21Ne-Rb-K comagnetometer

We develop a new comagnetometer using (21)Ne atoms with nuclear spin I=3/2 and Rb atoms polarized by spin exchange with K atoms to search for tensor interactions that violate local Lorentz invariance. We frequently reverse the orientation of the experiment and search for signals at the first and second harmonics of the sidereal frequency. We constrain 4 of the 5 spatial Lorentz-violating coefficients c(jk)(n) that parametrize anisotropy of the maximum attainable velocity of a neutron at a level of 10(-29), improving previous limits by 2 to 4 orders of magnitude and placing the most stringent constraint on deviations from local Lorentz invariance.

Targeting SDF-1/CXCR4 to inhibit tumour vasculature for treatment of glioblastomas

Local recurrence of glioblastomas is a major cause of patient mortality after definitive treatment. This review discusses the roles of the chemokine stromal cell-derived factor-1 and its receptor CXC chemokine receptor 4 (CXCR4) in affecting the sensitivity of glioblastomas to irradiation. Blocking these molecules prevents or delays tumour recurrence after irradiation by inhibiting the recruitment of CD11b+ monocytes/macrophages that participate in revascularising the tumour. We review the literature pertaining to the mechanism by which revascularisation occurs following tumour irradiation using experimental models. Areas of interest and debate in the literature include the process by which endothelial cells die after irradiation and the identity/origin of the cells that reconstitute the tumour blood vessels after injury. Understanding the processes that mediate tumour revascularisation will guide the improvement of clinical strategies for preventing recurrence of glioblastoma after irradiation.

Unusual inverse temperature dependence on reaction rate in the asymmetric autocatalytic alkylation of pyrimidyl aldehydes

Observations of an intriguing inverse temperature dependence on reaction rate and a profound induction period in the Soai autocatalytic reaction are reported along with detailed kinetic and NMR investigations of the product alkoxide at low temperatures, leading to the suggestion that the active catalyst is derived in situ from the tetrameric ground state.

Association between bovine digital dermatitis treponemes and a range of 'non-healing' bovine hoof disorders

This study describes the association between bovine digital dermatitis (BDD) treponemes and three 'non-healing' bovine hoof horn lesions, namely, 'toe necrosis' (TN), 'non-healing white line disease' (nhWLD) and 'non-healing sole ulcer' (nhSU), which are disorders that involve penetration through the horn capsule to involve the corium. In this study, these non-healing disorders (n=44) were identified as foot lesions that exhibited a topical granular appearance, exuded a typical pungent smell, were severely painful to the animal involved, and typically originated from farms where BDD is endemic. Given the similarities between these 'non-healing' lesions and BDD, the authors subjected samples of diseased tissue to PCR assays to detect the presence of DNA of BDD treponemes. All the three characterised BDD treponeme groups were identified as present together in 84.2, 81.3 and 55.6 per cent of samples of TN (n=19), nhWLD (n=16) and nhSU (n=9), respectively. In contrast, healthy control horn samples from similar sites (n=16) were PCR-negative for the BDD treponemes. Hence, these non-healing hoof lesions were strongly associated with BDD treponemes. Samples from typical heel horn erosions (n=9) were also subjected to BDD treponeme PCR assays and no association could be identified between the BDD treponemes and this horn manifestation.

Comparison of treatment and outcome information between a clinical trial and the National Cancer Data Repository

BACKGROUND

Clinical trials are important but many factors limit their success, including the costs of long-term follow-up and participants often not being representative of the general population. The National Cancer Data Repository (NCDR) contains data about patients with cancer in England that may help overcome some of these problems. This study compared treatment and outcome information between the Medical Research Council Conventional versus Laparoscopic-Assisted Surgery in Colorectal Cancer (CLASICC) trial and the NCDR.

METHODS

Participants in the CLASICC trial were identified in the NCDR, and management and outcome data were compared. Data on all surgically treated English patients with colorectal cancer were extracted from the NCDR and compared with those of CLASICC participants.

RESULTS

Survival and treatment data for those in the CLASICC trial were available in the NCDR for 98·9 and 95·8 per cent of patients respectively. There was agreement in operation type for 86·1 per cent of patients but surgical approach coding was poor, with only 58·4 per cent of laparoscopic procedures coded in the NCDR. There was no significant difference in survival calculated from either data set. Surgical information was available in the NCDR for 19 of 20 trial participants with missing data. The trial population was younger (P < 0·001), of better socioeconomic status (P = 0·001) and with earlier disease (P < 0·001) than the general surgically treated colorectal cancer population. Rectal cancer survival was similar, but 5-year survival after treatment of colonic cancer was significantly better in the trial than in the national data: 57·1 (95 per cent confidence interval 51·5 to 62·3) versus 49·8 (49·3 to 50·2) per cent respectively.

CONCLUSION

The National Cancer Data Repository demonstrates potential for informing clinical trials, but limitations prevent full intention-to-treat analyses.

Bone marrow stromal cells inhibit mast cell function via a COX2-dependent mechanism

BACKGROUND

Mast cells (MCs) have a central role in the induction of allergic inflammation, such as seen in asthma, and contribute to the severity of certain autoimmune diseases, such as rheumatoid arthritis. The MC thus represents an important inflammatory cell, and one which has resisted therapeutic attempts to alter its role in disease.

OBJECTIVE

Because bone marrow-derived stromal cells (BMSC, also known as mesenchymal stem cells or MSCs) have been reported to alter allergic inflammation in vivo, we chose to study the interaction between mouse BMSC and mouse bone marrow-derived MCs.

METHODS

MC degranulation, cytokine production and chemotaxis were evaluated in vitro following co-culture with BMSCs either in cell contact or a transwell. In addition, MC degranulation was assessed in vivo following administration of BMSCs in a model of passive cutaneous anaphylaxis and a peritoneal degranulation assay. Mechanisms of MC suppression by BMSCs were determined through use of inhibitors or antibodies to COX1, COX2, nitric oxide, indoleamine 2, 3-dioxygenase, EP1-4 receptors, TGF-β and IL-10. Lastly, we utilized either BMSCs or MCs deficient in COX1, COX2 or EP1-4 receptors to confirm the mechanisms of inhibition of MC function by BMSCs.

RESULTS

We discovered that BMSCs will effectively suppress specific MC functions in vitro as well as in vivo. When MCs are cocultured with BMSCs to allow cell-to-cell contact, BMSCs suppressed MC degranulation, pro-inflammatory cytokine production, chemokinesis and chemotaxis. Similarly, MC degranulation within mouse skin or the peritoneal cavity was suppressed following in vivo administration of BMSCs. Further, we found that these inhibitory effects were dependent on up-regulation of COX2 in BMSCs; and were facilitated through the activation of EP4 receptors on MCs.

CONCLUSION AND CLINICAL RELEVANCE

These observations support the concept that BMSCs have the ability to suppress MC activation and therefore could be the basis for a novel cell based therapeutic approach in the treatment of MC driven inflammatory diseases.

Bone marrow stromal cells inhibit mast cell function via a COX2-dependent mechanism

BACKGROUND

Mast cells (MCs) have a central role in the induction of allergic inflammation, such as seen in asthma, and contribute to the severity of certain autoimmune diseases, such as rheumatoid arthritis. The MC thus represents an important inflammatory cell, and one which has resisted therapeutic attempts to alter its role in disease.

OBJECTIVE

Because bone marrow-derived stromal cells (BMSC, also known as mesenchymal stem cells or MSCs) have been reported to alter allergic inflammation in vivo, we chose to study the interaction between mouse BMSC and mouse bone marrow-derived MCs.

METHODS

MC degranulation, cytokine production and chemotaxis were evaluated in vitro following co-culture with BMSCs either in cell contact or a transwell. In addition, MC degranulation was assessed in vivo following administration of BMSCs in a model of passive cutaneous anaphylaxis and a peritoneal degranulation assay. Mechanisms of MC suppression by BMSCs were determined through use of inhibitors or antibodies to COX1, COX2, nitric oxide, indoleamine 2, 3-dioxygenase, EP1-4 receptors, TGF-β and IL-10. Lastly, we utilized either BMSCs or MCs deficient in COX1, COX2 or EP1-4 receptors to confirm the mechanisms of inhibition of MC function by BMSCs.

RESULTS

We discovered that BMSCs will effectively suppress specific MC functions in vitro as well as in vivo. When MCs are cocultured with BMSCs to allow cell-to-cell contact, BMSCs suppressed MC degranulation, pro-inflammatory cytokine production, chemokinesis and chemotaxis. Similarly, MC degranulation within mouse skin or the peritoneal cavity was suppressed following in vivo administration of BMSCs. Further, we found that these inhibitory effects were dependent on up-regulation of COX2 in BMSCs; and were facilitated through the activation of EP4 receptors on MCs.

CONCLUSION AND CLINICAL RELEVANCE

These observations support the concept that BMSCs have the ability to suppress MC activation and therefore could be the basis for a novel cell based therapeutic approach in the treatment of MC driven inflammatory diseases.

Five-year follow-up of the Medical Research Council CLASICC trial of laparoscopically assisted versus open surgery for colorectal cancer

INTRODUCTION

The UK Medical Research Council CLASICC trial assessed the safety and efficacy of laparoscopically assisted surgery in comparison with open surgery for colorectal cancer. The results of the 5-year follow-up analysis are presented.

METHODS

Five-year outcomes were analysed and included overall and disease-free survival, and local, distant and wound/port-site recurrences. Two exploratory analyses were performed to evaluate the effect of age (70 years or less, or more than 70 years) on overall survival between the two groups, and the effect of the learning curve.

RESULTS

No differences were found between laparoscopically assisted and open surgery in terms of overall survival, disease-free survival, and local and distant recurrence. Wound/port-site recurrence rates in the laparoscopic arm remained stable at 2.4 per cent. Conversion to open operation was associated with significantly worse overall but not disease-free survival, which was most marked in the early follow-up period. The effect of surgery did not differ between the age groups, and surgical experience did not impact on the 5-year results.

CONCLUSION

The 5-year analyses confirm the oncological safety of laparoscopic surgery for both colonic and rectal cancer. The use of laparoscopic surgery to maximize short-term outcomes does not compromise the long-term oncological results.

REGISTRATION NUMBER

ISRCTN74883561 (http://www.controlled-trials.com).

New limit on Lorentz- and CPT-violating neutron spin interactions

We performed a search for neutron spin coupling to a Lorentz- and CPT-violating background field using a magnetometer with overlapping ensembles of K and ³He atoms. The comagnetometer is mounted on a rotary platform for frequent reversal of its orientation. We measure sidereal oscillations in the signal to search for anomalous spin coupling of extra-solar origin. We determine the equatorial components of the background field interacting with the neutron spin to be b˜Xn=(0.1 ± 1.6) × 10⁻³³ GeV and b˜Yn=(2.5 ± 1.6) × 10⁻³³ GeV, improving on the previous limit by a factor of 30. This measurement represents the highest energy resolution of any spin anisotropy experiment.

How well are graduates prepared for practice when measured against the latest GMC recommendations?

This article investigates the perspectives of University of Liverpool graduate foundation doctors and their consultants on their preparedness for professional practice.