Endoscopic ultrasound-guided intratumoural therapy for pancreatic cancer.

Pancreatic cancer is the second most frequent gastrointestinal malignancy and carries a dismal prognosis. The current standard of care includes resection, if possible, as well as systemic chemoradiation therapy. Endoscopic ultrasound (EUS) is an established technique for the diagnosis and staging of pancreatic adenocarcinoma.

Risk-reducing total gastrectomy for germline mutations in E-cadherin (CDH1): pathologic findings with clinical implications.

Hereditary diffuse gastric cancer is a rare autosomal dominant cancer susceptibility syndrome caused by germline E-cadherin (CDH1) mutations in 40% of cases with a high degree of penetrance. Screening endoscopy has not been useful in identifying early cancer, in part owing to conflicting data concerning site(s) of involvement in the stomach and the lack of endoscopically detectable pathology. Risk-reducing total gastrectomy specimens from 8 asymptomatic adults with germline mutations in the CDH1 gene (3 different pedigrees) were studied using a sequential serial sectioning protocol with submission of the entire stomach for histologic analysis.

Fiber-optic probe for noninvasive real-time determination of tissue optical properties at multiple wavelengths.

We present a compact, fast, and versatile fiber-optic probe system for real-time determination of tissue optical properties from spatially resolved continuous-wave diffuse reflectance measurements. The system collects one set of reflectance data from six source-detector distances at four arbitrary wavelengths with a maximum overall sampling rate of 100 Hz. Multivariate calibration techniques based on two-dimensional polynomial fitting are employed to extract and display the absorption and reduced scattering coefficients in real-time mode.

Quantifying the absorption and reduced scattering coefficients of tissuelike turbid media over a broad spectral range with noncontact Fourier-transform hyperspectral imaging.

Absorption (mu(a)) and reduced scattering (mu(s)') spectra of turbid media were quantified with a noncontact imaging approach based on a Fourier-transform interferometric imaging system (FTIIS). The FTIIS was used to collect hyperspectral images of the steady-state diffuse reflectance from turbid media. Spatially resolved reflectance data from Monte Carlo simulations were fitted to the recorded hyperspectral images to quantify mu(a) and mu(s)' spectra in the 550-850-nm region.

Combined experimental and theoretical mechanistic investigation of the Barbier allylation in aqueous media.

The Barbier allylation of a series of para-substituted benzaldehydes with allylbromide in the presence of Zn, In, Sn, Sb, Bi, and Mg was investigated using competition experiments. In all cases, the slope of the Hammett plots indicated a build-up of negative charge in the selectivity-determining step. For Zn, In, Sn, Sb, and Bi, an inverse secondary kinetic isotope effect was found (kH/kD = 0.

Multiple polynomial regression method for determination of biomedical optical properties from integrating sphere measurements.

We present a new, to our knowledge, method for extracting optical properties from integrating sphere measurements on thin biological samples. The method is based on multivariate calibration techniques involving Monte Carlo simulations, multiple polynomial regression, and a Newton-Raphson algorithm for solving nonlinear equation systems. Prediction tests with simulated data showed that the mean relative prediction error of the absorption and the reduced scattering coefficients within typical biological ranges were less than 0.

Sexual risk behaviour and HAART: a comparative study of HIV-infected persons on HAART and on preventive therapy in Kenya.

Unprotected sex (UPS) among persons receiving highly active antiretroviral therapy (HAART) remains a concern because of the risk of HIV-transmission. A cross-sectional study comparing the sexual risk behaviour of 179 people living with HIV/AIDS (PLHA) receiving HAART with that of 143 PLHA receiving preventive therapy (PT) with cotrimoxazole/isoniazid was conducted in Mombasa, Kenya. Forty-five percent of all participants were sexually active in the last six months.

Diagnosis of pancreatic gastrointestinal stromal tumor by EUS guided FNA.

Context: Gastrointestinal stromal tumors of the pancreas are very rare. Only two case reports have been published, both with diagnoses made on surgical pathology. We present the first case of pancreatic stromal tumor diagnosed by endoscopic ultrasound guided fine needle aspiration.

Diffuse reflectance spectroscopy of human adenomatous colon polyps in vivo.

Diffuse reflectance spectra were collected from adenomatous colon polyps (cancer precursors) and normal colonic mucosa of patients undergoing colonoscopy. We analyzed the data by using an analytical light diffusion model, which was tested and validated on a physical tissue model composed of polystyrene beads and hemoglobin. Four parameters were obtained: hemoglobin concentration, hemoglobin oxygen saturation, effective scatterer density, and effective scatterer size.

Adherence to antiretroviral therapy & its determinants amongst HIV patients in India.

Background & Objective: Very high levels of adherence are required for ART to be effective. There is limited information available from India on adherence to ART and its predictors. We carried out this study to examine adherence levels and to explore the factors associated with adherence among PLHA receiving ART in India.

Mathematical model of fluorescence endoscopic image formation.

We present a mathematical model that describes the spatial distribution of photons in fluorescence endoscopic images, resulting in expressions for image signal-to-noise ratio and resolution. This model was applied to quantitative analysis of fluorescence images collected from human colonic mucosa with a fiber-optic and an electronic endoscope. It provides a tool for the design of fluorescence endoscopic imaging systems and for extraction of quantitative information about image features.

Quantitative analysis of metabolites in complex biological samples using ion-pair reversed-phase liquid chromatography-isotope dilution tandem mass spectrometry.

A rapid, sensitive and selective ion-pair reversed-phase liquid chromatography-electrospray ionization isotope dilution tandem mass spectrometry (IP-LC-ESI-ID-MS/MS) was developed for quantitative analysis of free intracellular metabolites in cell cultures. As an application a group of compounds involved in penicillin biosynthesis pathway of Penicillium chrysogenum cells, such as penicillin G (PenG), 6-aminopenicillanic acid (6-APA), benzylpenicilloic acid (PIO), ortho-hydroxyphenyl acetic acid (o-OH-PAA), phenylacetic acid (PAA), 6-oxopipeidine-2-carboxylic acid (OPC), 8-hydroxypenicillic acid (8-HPA), L-alpha-(delta-aminoadipyl)-L-alpha-cystenyl-D-alpha-valine (ACV) and isopenicillin N (IPN) were chosen. (13)C-labeled analogs of the metabolites were added to the sample solutions as internal standards (I.

Determination of tissue optical properties from diffuse reflectance profiles by multivariate calibration.

We describe a method for determining the reduced scattering and absorption coefficients of turbid biological media from the spatially resolved diffuse reflectance. A Sugeno Fuzzy Inference System in conjunction with data preprocessing techniques is employed to perform multivariate calibration and prediction on reflectance data generated by Monte Carlo simulations. The preprocessing consists of either a principal component analysis or a new, extended curve-fitting procedure originating from diffusion theory.

Use of flexible endoscopic scissors to cut obstructing suture material in gastric bypass patients.

With the epidemic increase in obesity in the USA and consequent increased demand for bariatric surgery, new complications of the surgery are being described. The most common surgery practiced is the Roux-en-Y gastric bypass (RYGBP). Unraveling of suture material at the gastrojejunal anastomosis may occur, which may be troublesome if nonabsorbable suture is employed.

Silencing of OB-RGRP in mouse hypothalamic arcuate nucleus increases leptin receptor signaling and prevents diet-induced obesity.

Obesity is a major public health problem and is often associated with type 2 diabetes mellitus, cardiovascular disease, and metabolic syndrome. Leptin is the crucial adipostatic hormone that controls food intake and body weight through the activation of specific leptin receptors (OB-R) in the hypothalamic arcuate nucleus (ARC). However, in most obese patients, high circulating levels of leptin fail to bring about weight loss.

2D optical manipulation and assembly of shape-complementary planar microstructures.

Optical trapping and manipulation offer great flexibility as a non-contact microassembly tool. Its application to the assembly of microscale building blocks may open new doors for micromachine technology. In this work, we demonstrate all-optical assembly of microscopic puzzle pieces in a fluidic environment using programmable arrays of trapping beams.

Fully automated beam-alignment and single stroke guided manual alignment of counter-propagating multi-beam based optical micromanipulation systems.

In a previous paper [J. S. Dam et al, Opt.

CDH1 truncating mutations in the E-cadherin gene: an indication for total gastrectomy to treat hereditary diffuse gastric cancer.

Background: Approximately 1% to 3% of all gastric cancers are associated with families exhibiting an autosomal dominant pattern of susceptibility. E-cadherin (CDH1) truncating mutations have been shown to be present in approximately 30% of families with hereditary diffuse gastric cancer (HDGC) and are associated with a significantly increased risk of gastric cancer and lobular breast cancer.

Methods: Individuals from a large kindred with HDGC who were identified to have a CDH1 mutation prospectively underwent comprehensive screening with stool occult blood testing, standard upper gastrointestinal endoscopy with random gastric biopsies, high-magnification endoscopy with random gastric biopsies, endoscopic ultrasonography, CT, and PET scans to evaluate the stomach for occult cancer.

Development of a TLD mailed system for remote dosimetry audit for (192)Ir HDR and PDR sources.

Background And Purpose: In the framework of an ESTRO ESQUIRE project, the BRAPHYQS Physics Network and the EQUAL-ESTRO laboratory have developed a procedure for checking the absorbed dose to water in the vicinity of HDR or PDR sources using a mailed TLD system. The methodology and the materials used in the procedure are based on the existing EQUAL-ESTRO external radiotherapy dose checks.

Materials And Methods: A phantom for TLD postal dose assurance service, adapted to accept catheters from different HDR afterloaders, has been developed.

Computerized "drag-and-drop" alignment of GPC-based optical micromanipulation system.

In the past, aligning the counterpropagating beams in our 3D real-time generalized phase contrast (GPC) trapping system has been a task requiring moderate skills and prior experience with optical instrumentation. A ray transfer matrix analysis and computer-controlled actuation of mirrors, objective, and sample stage has made this process user friendly. The alignment procedure can now be done in a very short time with just a few drag-and-drop tasks in the user-interface.

Single quantum dot nanowire LEDs.

We report reproducible fabrication of InP-InAsP nanowire light-emitting diodes in which electron-hole recombination is restricted to a quantum-dot-sized InAsP section. The nanowire geometry naturally self-aligns the quantum dot with the n-InP and p-InP ends of the wire, making these devices promising candidates for electrically driven quantum optics experiments. We have investigated the operation of these nanoLEDs with a consistent series of experiments at room temperature and at 10 K, demonstrating the potential of this system for single photon applications.

A novel retrograde-viewing auxiliary imaging device (Third Eye Retroscope) improves the detection of simulated polyps in anatomic models of the colon.

Background: Colonoscopy is the "gold standard" for colorectal polyp and cancer detection, but important lesions may be missed on the proximal aspect of haustral folds, rectal valves, or flexures.

Objective: Our purpose was to evaluate a prototype auxiliary imaging device that extends beyond the colonoscope's tip, providing a continuous retrograde view to detect lesions missed by the forward-viewing colonoscope.

Design: Three anatomic models of the colon were prepared with simulated polyps, 32% in obvious locations and 68% on the proximal aspect of folds.