Expression of human cationic trypsinogen (PRSS1) in murine acinar cells promotes pancreatitis and apoptotic cell death

Hereditary pancreatitis (HP) is an autosomal dominant disease that displays the features of both acute and chronic pancreatitis. Mutations in human cationic trypsinogen (PRSS1) are associated with HP and have provided some insight into the pathogenesis of pancreatitis, but mechanisms responsible for the initiation of pancreatitis have not been elucidated and the role of apoptosis and necrosis has been much debated. However, it has been generally accepted that trypsinogen, prematurely activated within the pancreatic acinar cell, has a major role in the initiation process. Functional studies of HP have been limited by the absence of an experimental system that authentically mimics disease development. We therefore developed a novel transgenic murine model system using wild-type (WT) human PRSS1 or two HP-associated mutants (R122H and N29I) to determine whether expression of human cationic trypsinogen in murine acinar cells promotes pancreatitis. The rat elastase promoter was used to target transgene expression to pancreatic acinar cells in three transgenic strains that were generated: Tg(Ela-PRSS1)NV, Tg(Ela-PRSS1*R122H)NV and Tg(Ela-PRSS1*N29I)NV. Mice were analysed histologically, immunohistochemically and biochemically. We found that transgene expression is restricted to pancreatic acinar cells and transgenic PRSS1 proteins are targeted to the pancreatic secretory pathway. Animals from all transgenic strains developed pancreatitis characterised by acinar cell vacuolisation, inflammatory infiltrates and fibrosis. Transgenic animals also developed more severe pancreatitis upon treatment with low-dose cerulein than controls, displaying significantly higher scores for oedema, inflammation and overall histopathology. Expression of PRSS1, WT or mutant, in acinar cells increased apoptosis in pancreatic tissues and isolated acinar cells. Moreover, studies of isolated acinar cells demonstrated that transgene expression promotes apoptosis rather than necrosis. We therefore conclude that expression of WT or mutant human PRSS1 in murine acinar cells induces apoptosis and is sufficient to promote spontaneous pancreatitis, which is enhanced in response to cellular insult.

Spin squeezing in a Rydberg lattice clock

We theoretically demonstrate a viable approach to spin squeezing in optical lattice clocks via optical dressing of one clock state to a highly excited Rydberg state, generating switchable atomic interactions. For realistic experimental parameters, these interactions are shown to generate over 10 dB of squeezing in large ensembles within a few microseconds and without degrading the subsequent clock interrogation.

Mitral valve closure prediction with 3-D personalized anatomical models and anisotropic hyperelastic tissue assumptions

This study is concerned with the development of patient-specific simulations of the mitral valve that use personalized anatomical models derived from 3-D transesophageal echocardiography (3-D TEE). The proposed method predicts the closed configuration of the mitral valve by solving for an equilibrium solution that balances various forces including blood pressure, tissue collision, valve tethering, and tissue elasticity. The model also incorporates realistic hyperelastic and anisotropic properties for the valve leaflets. This study compares hyperelastic tissue laws with a quasi-elastic law under various physiological parameters, and provides insights into error sensitivity to chordal placement, allowing for a preliminary comparison of the influence of the two factors (chords and models) on error. Predictive errors show the promise of the method, yielding aggregate median errors of the order of 1 mm, and computed strains and stresses show good correspondence with those reported in prior studies.

Organic livestock production: an emerging opportunity with new challenges for producers in tropical countries

Agrochemicals, veterinary drugs, antibiotics and improved feeds can increase the food supply while minimising production costs in various livestock production systems around the world. However, these days, quality-conscious consumers are increasingly seeking environmentally safe, chemical-residue-free healthy foods, along with product traceability and a high standard of animal welfare, which organic production methods are said to ensure. Organic production is not only a challenge for producers in developing countries, it offers new export opportunities as well. Organic agriculture is practised by 1.8 million producers in 160 countries, and production of organically grown food continues to increase steadily by 15% per year. Most tropical countries are now exporting organic agricultural products but, apart from organic beef from Brazil and Argentina, organic livestock products are yetto take off. Most trade in organic livestock products is restricted to the European Union and other developed nations. Nevertheless, tropical countries cannot afford to neglect this emerging system of animal production. Organic production is knowledge- and management-intensive. Producers must be well versed in organic production standards, principles and practices, which require a high degree of knowledge and skill. In organic production, it is not simply the final product but the whole production process that must be inspected and approved by the accredited certification bodies. Organic livestock farming is still evolving, and further research is needed to make it sustainable. In this paper, the authors review the prospects of organic animal husbandry and its possible constraints in developing and tropical countries.

Effect of solutal Marangoni convection on motion, coarsening, and coalescence of droplets in a monotectic system

In this paper, we study the effect of solutal Marangoni convection (SMC) on the microstructure evolution in a monotectic system, using the convective Cahn-Hilliard and Navier-Stokes equations with a capillary tensor contributed by the chemical concentration gradient. At first, we simulate the spontaneous motion of two distant droplets induced by SMC and compare our results with an analytical solution. We then compute the coalescence of two droplets in contact and coarsening of two distant droplets considering different sizes. We further study the influence of SMC on the evolution of phase separation processes inside the spinodal region for Fe-50 at %Sn and Fe-40 at %Sn alloys. In the former case, we rationalize our results using Fourier spectra and in the latter case, we compare the size distribution of droplets with the LSW theory.

Systematic review and meta-analysis of outcomes after intraoperative pancreatic duct stent placement during pancreaticoduodenectomy

BACKGROUND

Postoperative pancreatic leakage after pancreaticoduodenectomy is often serious. Although some studies have suggested that stenting the anastomosis can reduce the incidence of this complication, the value of stenting in the setting of pancreaticoduodenectomy remains unclear.

METHODS

Studies comparing outcomes of stent versus no stent, and internal versus external stent placement for pancreaticoduodenectomy were eligible for inclusion. Pooled odds ratios (ORs) with 95 per cent confidence intervals were calculated using fixed- or random-effects models.

RESULTS

From a search of the literature published between January 1973 and September 2011, five randomized clinical trials (RCTs) and 11 non-randomized observational clinical studies (OCS) involving 1726 patients were selected for inclusion in this review. Meta-analysis of RCTs revealed that placing a stent in the pancreatic duct did not reduce the incidence of postoperative pancreatic fistula. External stents had no advantage over internal stents in terms of clinical outcome. Subgroup analyses revealed that use of an external stent significantly reduced the incidence of pancreatic fistula (RCTs: OR 0·42, 0·24 to 0·76, P = 0·004; OCS: OR 0·43, 0·27 to 0·68, P < 0·001), delayed gastric emptying (RCTs: OR 0·41, 0·19 to 0·87, P = 0·02) and postoperative morbidity (RCTs: OR 0·55, 0·34 to 0·89, P = 0·02) compared with no stent.

CONCLUSION

Pancreatic duct stenting did not reduce the incidence of pancreatic fistula and other complications in pancreaticoduodenectomy compared with no stenting. Although no difference was found between external and internal stents in terms of efficacy, external stents seemed to reduce the incidence of pancreatic fistula compared with control.

A personalized mitral valve closure simulator

We describe a method for performing modeling and simulation to predict the closure of the Mitral Valve (MV) using patient specific anatomical information derived from 3D Transesophageal Echocardiography (3D TEE). The ability to predict the MV closure behavior is an important step along the way of developing personalized simulation tools that would allow a surgeon to perform preoperative planning and decide between various MV repair options. While the MV is an important use case because of its relevance and prevalence among reconstructive cardiac interventions, the study described here can provide a blueprint to perform pre-operative planning for other cardiac surgical interventions. The method reported here exploits the Saint Venant-Kirchhoff elasticity model that is tuned to match empirical observations of the MV strainstress behavior. Using intraoperative 3D TEE data, the proposed simulator was evaluated over 10 test cases and resulted in mean prediction absolute error values of 1.81 mm.

Valvular closure prediction using anisotropic and hyperelastic tissue models and individualized anatomy derived from RT3DE

We describe a method for modeling the closure of the Mitral Valve (MV) and to compute realistic strain and stresses in MV tissues. This informs preoperative planning by allowing a surgeon to evaluate various MV repairs options. The modeling method exploits individualized (patient-specific) anatomical structure recovered from real-time 3D echocardiography (RT3DE). This study utilizes hyperelastic models of the MV tissues and employs patient specific leaflets, chordal length assessment and annulus shapes. We report experiments on ten intraoperative test cases, where we compute strain and stresses using several different tissue models from MV empirical studies by May-Newman and Holzapfel.

Understanding the role of stimulation in reflexology: development and testing of a robotic device

Reflexology is a common choice of women with breast cancer as supportive care during treatment. It involves stimulation of specific locations of the feet called reflexes using a specialised walking motion with the thumb of the reflexologist. Reflexology has shown potential for the successful management of cancer and treatment-related symptoms and improvement in physical functioning; however to date, the mechanism of action for these improvements is unknown. One confounder to the study of reflexology is the 'human factor'. To study the effects of the stimulation of the reflexes independent of the 'human factor', there is a need for an alternative method for the delivery of reflexology. The objective of this work was to design and create a robotic reflexology device that would deliver a breast cancer-specific reflexology protocol to the feet of patients. A prototype robotic reflexology device was developed and tested for feasibility, safety and acceptability with breast cancer survivors (n= 13), and preliminary efficacy in symptom management and enhanced functional status with a sample of women undergoing chemotherapy for breast cancer (n= 13). Safety, feasibility and acceptability were established, and significant improvements from pre- to post-device-delivered reflexology were seen in symptom severity among women on chemotherapy.

Upregulation of MAPK pathway is associated with survival in castrate-resistant prostate cancer

Background:

Recent evidence has implicated the MAP kinase (MAPK) pathway with the development of castrate-resistant prostate cancer (CRPC). We have previously reported gene amplification of critical members of this pathway with the development of castrate-resistant disease. In addition, we have shown that rising Raf-1 expression, with the development of CRPC, influences time to biochemical relapse. We therefore sought to further analyse the role of both Raf-1 and its downstream target MAPK in the molecular pathogenesis of CRPC.

Methods:

Protein expression of Raf-1 and MAPK, including their activation status, was analysed using immunohistochemistry in a database of 65 paired tumour specimens obtained before and after the development of CRPC and correlated with other members of the pathway.

Results:

Patients whose nuclear expression of MAPK rose with the development of CRPC had a significantly shorter median time to death following biochemical relapse (1.40 vs 3.00 years, P=0.0255) as well as reduced disease-specific survival when compared with those whose expression fell or remained unchanged (1.16 vs 2.62 years, P=0.0005). Significant correlations were observed between protein expression of Raf-1 and MAPK with the type 1 receptor tyrosine kinases, Her2 and epidermal growth factor receptor, as well as the transcription factor AP-1 in CRPC tumours.

Conclusion:

We conclude that the Her2/Raf-1/MAPK/AP-1 axis may promote the development of CRPC, leading to early relapse, and reduced disease-specific survival. In addition, members of the pathway may act as novel therapeutic and/or diagnostic targets for prostate cancer.