Detecting regional lung properties using audio transfer functions of the respiratory system

In this study, a novel instrument has been developed for measuring changes in the distribution of lung fluid the respiratory system. The instrument consists of a speaker that inputs a 0-4kHz White Gaussian Noise (WGN) signal into a patient's mouth and an array of 4 electronic stethoscopes, linked via a fully adjustable harness, used to recover signals on the chest surface. The software system for processing the data utilizes the principles of adaptive filtering in order to obtain a transfer function that represents the input-output relationship for the signal as the volume of fluid in the lungs is varied. A chest phantom model was constructed to simulate the behavior of fluid related diseases within the lungs through the injection of varying volumes of water. Tests from the phantom model were compared to healthy subjects. Results show the instrument can obtain similar transfer functions and sound propagation delays between both human and phantom chests.

Elimination of symbiotic Aeromonas spp. from the intestinal tract of the medicinal leech, Hirudo medicinalis, using ciprofloxacin feeding

The use of the medicinal leech (Hirudo medicinalis) in promoting venous drainage in tissues whose vitality is threatened by venous congestion and obstruction, especially in plastic and reconstructive surgery, has been complicated by infections caused by Aeromonas spp. These are leech endosymbionts for which patients undergoing hirudotherapy frequently receive systemic chemoprophylaxis. In order to evaluate the possibility of rendering leeches safe for use on patients, H. medicinalis were fed artificially with a 2 g/L arginine solution (used as a phagostimulant) supplemented with ciprofloxacin (100 mg/L). Aeromonads were detected in 57 out of 80 control leeches (71.3%), but in none of the 56 leeches treated with ciprofloxacin (p <0.001). Treated leeches survived for up to 4 months. Tested weekly, 61% of these leeches took human blood for at least 4 weeks after treatment and all remained negative for aeromonads. All water samples in which leeches were kept before treatment were contaminated with Aeromonas spp.; none were detected in any of the NaCl/arginine solutions with which treated animals were fed. Molecular characterization of two phenotypically distinct isolates using gyrB sequencing showed that one clustered tightly with A. veronii and the other was closely related to A. media. Other environmental bacteria and fungi were isolated from 26.5% of treated leeches that had taken a blood meal 1-4 weeks after treatment. Ciprofloxacin reduced the number of leech-associated aeromonads to undetectable levels for extended periods. Most treated leeches were ready to take a blood meal after treatment, suggesting the possibility of using ciprofloxacin-treated leeches instead of chemoprophylaxis in patients undergoing hirudotherapy.

Acquisition of vancomycin-resistant enterococci in internal medicine wards

BACKGROUND

Our institution experienced an increase in the frequency of vancomycin-resistant enterococci (VRE) clinical isolates, which rose 5-fold from 2004 to 2005. We sought to measure the prevalence of VRE carriage among medical inpatients in a tertiary hospital in Jerusalem and estimate the rate of acquisition during hospitalization.

METHODS

During 2006, we performed 3 cross-sectional surveys, including 1039 patients, representing 3 phases of hospitalization: admission, hospital stay, and discharge. Perianal/stool samples were cultured for VRE.

RESULTS

VRE carriage was 3.8% (95% confidence interval [CI] = 1.8% to 6.9%) on admission, 15% (95% CI = 9% to 23%) at discharge, and 32% (95% CI = 24% to 40%) among inpatients. Among inpatient carriers, 60% of the isolates represented a single strain. Recent previous hospitalization was the most significant predictor for identifying carriers on admission.

CONCLUSIONS

Our study demonstrates that substantial VRE transmission occurred during hospitalization. Identification of carriers on admission should supplement effective application of infection control methods in attempting to decrease VRE nosocomial spread and burden.

A prospective randomised study on narrow-band imaging versus conventional colonoscopy for adenoma detection: does narrow-band imaging induce a learning effect?

BACKGROUND AND AIMS

Colonoscopy is an established method of colorectal cancer screening, but has an adenoma miss rate of 10-20%. Detection rates are expected to improve with optimised visualisation methods. This prospective randomised study evaluated narrow-band imaging (NBI), a new technique that may enhance image contrast in colon adenoma detection.

METHODS

Eligible patients presenting for diagnostic colonoscopy were randomly assigned to undergo wide-angle colonoscopy using either conventional high-resolution imaging or NBI during instrument withdrawal. The primary outcome parameter was the difference in the adenoma detection rate between the two techniques.

RESULTS

A total of 401 patients were included (mean age 59.4 years, 52.6% men). Adenomas were detected more frequently in the NBI group (23%) than in the control group (17%) with a number of 17 colonoscopies needed to find one additional adenoma patient; however, the difference was not statistically significant (p = 0.129). When the two techniques were compared in consecutive subgroups of 100 study patients, adenoma rates in the NBI group remained fairly stable, whereas these rates steadily increased in the control group (8%, 15%, 17%, and 26.5%, respectively). Significant differences in the first 100 cases (26.5% versus 8%; p = 0.02) could not be maintained in the last 100 cases (25.5% versus 26.5%, p = 0.91).

CONCLUSIONS

The increased adenoma detection rate means of NBI colonoscopy were statistically not significant. It remains speculative as to whether the increasing adenoma rate in the conventional group may have been caused by a training effect of better polyp recognition on NBI.

Image processing system for ultrasound images of the eye

Closed Angle Glaucoma causes an increase in fluid pressure in the eye due to decreased fluid flow between the iris and the cornea. To diagnose Glaucoma, ultrasound images of the eye are taken and a technician studies the images and takes measurements. This process is time consuming, and results vary among technicians. In a previous paper, we developed an image processing algorithm to extract several key landmark features in the iris. In this paper, we extend this algorithm to calculate the complete set of diagnostic parameters from ultrasound biomicroscopy. A robust algorithm is described to calculate the parameters which describe the thickness of iris; ID1, ID2, and ID3. The method is tested on 89 clinical images and compared to the values identified by the technician. Results indicate good agreement in 97% of cases.

Culture-based methods for detection and identification of Streptococcus agalactiae in pregnant women--what are we missing?

We aimed to compare BD group B Streptococcus differential agar (GBSDA) with inoculation into LIM broth and subculture onto blood agar plates (LIM-BA) as a method for GBS screening in pregnant women. First, we compared the detection threshold and the ease of use of GBSDA with LIM-BA by inoculating known numbers of GBS mixed with approximately 10(5) cfu of other bacteria. Second, we tested the production of carotenoid pigment in 155 GBS blood culture isolates. Finally, we compared GBSDA, LIM broth with direct GBS antigen detection (LIM-AG) and LIM-BA as methods for GBS screening in pregnant women. GBS colonies were easily detected on GBSDA at a threshold of 20 cfu. In contrast, GBS was not detected in a mixed culture from LIM broth with initial inocula of up to 100 cfu. Orange pigment was produced in 146/155 GBS blood culture isolates. Pigment was not produced in eight non-hemolytic and two hemolytic strains. GBS was detected by GBSDA in 58 out of 297 parturient women (19.5%) but in only 50 (16.8%, P > 0.05) and 46 (15.4%, P = 0.079) women by LIM-BA and LIM-AG, respectively. GBSDA is a satisfactory medium for the rapid detection of most GBS isolates, but other methods may be needed if detection of all non-pigmented strains is required.

Ten-year experience with preimplantation genetic diagnosis (PGD) at the New York University School of Medicine Fertility Center

We describe our experience of over 300 cycles of preimplantation genetic diagnosis (PGD) and report clinical pregnancy rates (35%-67%) that support using this technology to screen for genetic disorders and chromosomal abnormalities. In clinical practice for over ten years, PGD offers couples the earliest form of genetic screening and may help improve ongoing pregnancy rates in poor-prognosis patients.

Pichia farinosa bloodstream infection in a lymphoma patient

We describe a case of Pichia farinosa bloodstream infection in a lymphoma patient. Phenotypic methods failed to identify the isolate, which was identified by sequence-based methods. This case highlights the importance of implementing molecular methods for the identification of rare fungal pathogens.

Electrode placement configurations for 3D EIT

This paper investigates several configurations for placing electrodes on a 3D cylindrical medium to reconstruct 3D images using 16 electrode EIT equipment intended for use with a 2D adjacent drive protocol. Seven different electrode placement configurations are compared in terms of the following figures of merit: resolution, radial and vertical position error, image magnitude, immunity to noise, immunity to electrode placement errors, and qualitative evaluation of image artefacts. Results show that for ideal conditions, none of the configurations considered performed significantly better than the others. However, when noise and electrode placement errors were considered the planar electrode placement configuration (two rings of vertically aligned electrodes with electrodes placed sequentially in each ring) had the overall best performance. Based on these results, we recommend planar electrode placement configuration for 3D EIT lung imaging of the thorax.

Changes in qnr prevalence and fluoroquinolone resistance in clinical isolates of Klebsiella pneumoniae and Enterobacter spp. collected from 1990 to 2005

Clinical isolates of Klebsiella pneumoniae and Enterobacter spp. collected from 1990 through 2005 at a tertiary care center were studied for qnr genes. Isolates bearing these genes emerged in the mid-1990s, coinciding with the time of a rapid increase in fluoroquinolone resistance. Sixty percent of these isolates were ciprofloxacin susceptible by CLSI breakpoints.

Precision control of eluted activity from a Sr/Rb generator for cardiac positron emission tomography

A rubidium-82 (/sup 82/Rb) elution system is described for use with clinical positron emission tomography. The system is self-calibrating with 1.4% repeatability, independent of generator activity and elution flow rate. Saline flow is switched between a /sup 82/Sr//sup 82/Rb generator and a bypass line to achieve a constant activity elution of /sup 82/Rb. In the present study, pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control algorithm is developed which produces a constant activity elution within the constraints of long feedback delay and short elution time. Accurate constant-activity elutions of 10-70% of the total generator activity were demonstrated using the threshold comparison control. The adaptive-corrective control of the PWM valve provided a substantial improvement in precision of the steady-state output.