Oncological Efficacy of Robotic Nephroureterectomy vs. Open and Laparoscopic Nephroureterectomy for Suspected Non-Metastatic UTUC-A Systematic Review and Meta-Analysis

INTRODUCTION AND AIMS

The optimal approach for nephroureterectomy in patients with suspected UTUC remains a point of debate. In this review, we compare the oncological outcomes of robotic nephroureterectomy (RNU) with open (ONU) or laparoscopic nephroureterectomy (LNU).

METHODS

All randomized trials and observational studies comparing RNU with ONU and/or LNU for suspected non-metastatic UTUC are included in this review. The systematic review was performed in accordance with the Cochrane Guidelines and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The primary outcome measures were overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS), and intravesical recurrence-free survival (IV-RFS). The secondary outcome measures were the lymph node dissection (LND) rates, positive margin rates, and the proportion of patients receiving bladder intravesical chemotherapy.

RESULTS

We identified 8172 references through our electronic searches and 8 studies through manual searching. A total of 15 studies met the inclusion criteria. The total number of patients in the review was 18,964. RNU had superior OS compared to LNU (HR: 0.81 (95% CI: 0.71, 0.93), p-0.002 (very low certainty)). RNU and ONU had similar OS (HR: 0.83 (95% CI: 0.52, 1.34), p-0.44 (very low certainty)). One study reported an independent association of RNU as a worse predictor of IV-RFS when compared to ONU (HR-1.73 (95% CI: 1.22, 2.45)). The LND rates were higher in the RNU cohort when compared to the LNU cohort (RR 1.24 (95% CI: 1.03, 1.51), p-0.03 (low certainty)). The positive margin rate was lower in the RNU cohort when compared to the ONU cohort (RR 0.29 (95% CI: 0.08, 0.86), p-0.03 (low certainty)).

CONCLUSION

RNU offers comparable oncological efficacy to ONU, except for intravesical recurrence-free survival (IV-RFS). RNU has fewer positive surgical margin rates compared to ONU in well-balanced studies. RNU appears to outperform LNU for certain oncological parameters, such as OS and the proportion of patients who receive lymph node dissections. The quality of evidence comparing surgical techniques for UTUC has remained poor in the last decade.

Immunoexpression of TTF1 and p63 Differentiates Lung Adenocarcinomas in Sputum Samples

Context

Differentiating NSCLC as either adeno or squamous type and identification of Epidermal Growth Factor Receptor (EGFR) mutations is clinically relevant for lung cancer patients for selecting treatment. Thyroid transcription factor-1 (TTF-1) and p63 were demonstrated as useful markers for histologic typing of lung cancer. Mutation and overexpression of EGFR has been reported in a subset of non-small cell lung cancers. If these markers can be validated for the differential diagnosis of adenocarcinoma in a sputum sample itself, it will be highly beneficial for lung cancer patients.

Aims

To evaluate whether immunocytochemical expression of TTF-1, p63, and EGFR proteins in sputum samples can be used for differential diagnosis of lung adenocarcinoma by comparing with that of the corresponding tissue samples.

Settings and Design

Ninety sputum samples and matched tissue samples were used for the study.

Subjects and Methods

Monolayered smears and cell blocks of sputum and the corresponding tissue samples were immunostained with the standard ABC method. The expression patterns of these markers were analyzed statistically and compared with clinic-pathological parameters.

Statistical Analysis Used

Chi-square test and paired t-test.

Results

The p63 protein had a positive expression in 73.9% of SCC whereas TTF1 had positive expression in 75.8% of ADC. The EGFR expression was positive in 27 cases of adenocarcinoma, 21 cases of SCC and 19 cases of NSCLC.

Conclusions

Immunocytochemistry of the aforementioned antibodies in sputum samples can be used as supplementary evidence for the subtyping of NSCLC.

Gastric secretion in patients with caustic ingestion: A prospective study

BACKGROUND

Caustic ingestion can lead to structural changes in the upper gastrointestinal tract. However, there are limited data on the effect of caustic ingestion on gastric secretion. This study was planned to determine the changes in gastric acid output in patients with caustic ingestion.

METHODS

It was a prospective study done at a tertiary care center in northern India. Twenty consecutive patients in chronic phase of caustic ingestion were evaluated for the study. The gastric secretory function was estimated in the basal state and following pentagastrin stimulation. These results were compared with normal values for our laboratory.

RESULTS

The mean age of the included patients (n = 20) was 27.35 ± 2.96 years and 14 patients were male. Sixteen (80%) patients had a history of acid ingestion. Patients with caustic ingestion had significantly lower mean gastric acid secretion (0.8 ± 0.4 mEq/h vs. 4 ± 0.4 mEq/h; p < 0.001) compared to controls. After pentagastrin stimulation, the mean gastric juice volume (31.8 ± 6 mL/h vs. 62.3 ± 11.7 mL/h; p < 0.01) and acidity (15.3 ± 5.1 mEq/L vs. 39.6 ± 9.3 mEq/L; p < 0.001) increased in patients with caustic ingestion, but were lower than those in control subjects. Patients with a lower esophageal stricture (n = 6) had decreased maximum acid output (0.62 ± 0.32 mEq/h vs. 6.05 ± 0.55 mEq/h; p < 0.05) compared to patients with stricture in the upper or middle esophagus.

CONCLUSION

Caustic ingestion is associated with reduced gastric juice volume and acid output. Patients with stricture in the lower one third of the esophagus are at a higher risk of hypochlorhydria compared to patients with stricture in either the upper or middle esophagus.

Value-added switchgrass extractives for reduction of Escherichia coli O157:H7 and Salmonella Typhimurium populations on Formica coupons

Recurring outbreaks linked to Escherichia coli O157:H7-contaminated lettuce and Salmonella enterica-contaminated sprouts highlight the need for improved food safety measures. The aim of this study was to determine the ability of a bio-based antimicrobial extract prepared from switchgrass, a dedicated energy crop, to reduce E. coli O157:H7 and S. Typhimurium populations on Formica coupons, a model food-contact surface. Overnight cultures of ~7 log CFU/mL E. coli O157:H7 and S. Typhimurium, air-dried on Formica coupons were treated with 0.625% NaClO, 70% ethanol, sterile water or different batches of switchgrass extractives (SE1, SE2, and SE3) for up to 30 min. E. coli O157:H7 was reduced by 4.43 log CFU/mL after 1 min by SE3, and to non-detectable levels after 1 min by all other treatments. Populations of S. Typhimurium LT2 (15-min drying) were reduced by 3.30 log CFU/mL with 70% ethanol, 5.38 log CFU/mL with SE1, and to non-detectable levels with 0.625% NaClO after 1 min, while S. Typhimurium ATCC 23564 (1-h drying) was non-detectable after 1 min by all treatments. Under soiled conditions, 10-min treatment with SE1 and 70% ethanol reduced both bacteria to non-detectable levels. Studies with concentrated switchgrass extractives combined with various other natural disinfectants or in hurdle approaches warrant further investigation.

Black pearl in urology: Inadvertent anastomosis of gonadal vein to ureter leading to malpostioning of stent into the inferior vena cava

Double- J (JJ) stents are commonly used in urological procedures. Minor and self limiting complications are common following JJ stenting. Malpositioning of JJ stent into the vascular system is a rare and a possibly fatal complication. We are reporting a case of a malpositioned JJ stent in the inferior vena cava (IVC), during Boari flap procedure for post-hysterectomy uretereovaginal fistula. Patient had undergone hysterectomy three months previously, and had ureterovaginal fistula possibly due to iatrogenic intraoperative injury. Patient underwent right-sided ureteroneocystostomy with Boari flap one week previously at other institute. Patient was admitted in our institution with complaints of fever, pain in abdomen and vomiting. In view of the symptoms of the patient, cross-sectional imaging with computed tomography scan was done which revealed an intraoperatively malpositioned JJ stent in the IVC, and well healed Boari flap was seen.

Immunocytochemistry on Sputum Samples Predicts Prognosis of Lung Cancer

Context

Despite sputum cytology being accepted as a simple and noninvasive diagnostic method for lung cancer, the clinical usefulness of sputum for evaluation of prognosis is yet to be explored. Validation of some of the markers in sputum for prognosis prediction will be highly useful for selective therapy.

Aims

This study was aimed to evaluate a reliable panel of immunocytochemical markers for their significance to predict survival.

Materials and Methods

We have analyzed the expression of p53, p16, galectin-3, and epidermal growth factor receptor (EGFR) proteins in sputum samples processed in a mucolytic agent/cellblock and compared the same with that of the corresponding tissue samples.

Results

Overexpression of p16 and EGFR was found to have a better survival benefit, whereas positive p53 and galectin-3 expressions had shorter period of survival. Expression patterns of all these four proteins were more or less similar in smears, cellblocks of sputum, and tissue samples except for slight changes in staining intensity which was not found to be statistically significant. No significant difference was found in the association of these proteins with survival pattern between sputum and tissue samples.

Conclusion

This is the first report of immunocytochemistry of a panel of markers on cells exfoliated in sputum samples which suggests that analysis of immunocytochemical markers in sputum samples can be attempted as a cost-effective and reliable predictor of prognosis and survival. Accumulation of mutated p53, overexpression of galectin-3, and lower expression of p16 and EGFR proteins were found to predict poor prognosis for lung cancer.

An informatics guided classification of miscible and immiscible binary alloy systems

The classification of miscible and immiscible systems of binary alloys plays a critical role in the design of multicomponent alloys. By mining data from hundreds of experimental phase diagrams, and thousands of thermodynamic data sets from experiments and high-throughput first-principles (HTFP) calculations, we have obtained a comprehensive classification of alloying behavior for 813 binary alloy systems consisting of transition and lanthanide metals. Among several physics-based descriptors, the slightly modified Pettifor chemical scale provides a unique two-dimensional map that divides the miscible and immiscible systems into distinctly clustered regions. Based on an artificial neural network algorithm and elemental similarity, the miscibility of the unknown systems is further predicted and a complete miscibility map is thus obtained. Impressively, the classification by the miscibility map yields a robust validation on the capability of the well-known Miedema’s theory (95% agreement) and shows good agreement with the HTFP method (90% agreement). Our results demonstrate that a state-of-the-art physics-guided data mining can provide an efficient pathway for knowledge discovery in the next generation of materials design.

A thicker chorion gives ova of Atlantic salmon (Salmo salar L.) the upper hand against Saprolegnia infections

Since the ban of malachite green in the fish farming industry, finding alternative ways of controlling Saprolegnia infections has become of utmost importance. Much effort has been made to elucidate the mechanisms by which Saprolegnia invades fish eggs. Little is known about the defence mechanisms of the hosts, making some eggs more prone to infection than others. One clue might lie in the composition of the eggs. As the immune system in the embryos is not developed yet, the difference in infection levels could be explained by factors influenced by the mother herself, by either transferring passive immunity, influencing the physical aspects of the eggs or both. One of the physical aspects that could be influenced by the female is the chorion, the extracellular coat surrounding the fish egg, which is in fact the first major barrier to be overcome by Saprolegnia spp. Our results suggest that a thicker chorion in eggs from Atlantic salmon gives a better protection against Saprolegnia spp. In addition to the identification of differences in sensitivity of eggs in a fish farm set-up, we were able to confirm these results in a laboratory-controlled challenge experiment.

Spectroscopic characterization of recently excavated archaeological potsherds from Tamilnadu, India with multi-analytical approach

A combined analytical study of potsherds excavated from different archaeological sites of Tamilnadu (Kavalapatti, Nattapuraki and Thamaraikulam villages), India are analyzed by spectroscopic techniques such as FTIR, X-ray diffraction, thermogravimetric analysis (TGA) and Scanning Electron Microscope (SEM) coupled with Energy Dispersive Spectrometer (EDS). FTIR and XRD techniques have been attempted to characterize the mineralogical composition, firing temperature and firing conditions of the archaeological potsherds. Thermogravimetric analysis (TGA) is the complementary study to estimate the firing temperature from characteristic thermal reactions in potsherds under controlled firing in inert gas atmosphere. Further, Scanning Electron Microscopy (SEM) equipped and coupled with an Energy Dispersive Spectrometer (EDS) to analyze internal morphology and chemical composition of the potsherds was used. From the results of the above techniques, the firing temperatures of potsherds were found to be greater than 650°C.

Prospective Case-Control Study to Evaluate the Role of Glutathione S Transferases (GSTT1 and GSTM1) Gene Deletion in Breast Carcinoma and Its Prognostic Significance

Breast cancer is the most common cause of cancer death in women with the incidence rising in young women. GST gene polymorphisms are significant because of their role in the detoxification of both environmental carcinogens and also cytotoxic drugs used in therapy for breast cancer. The present study has been designed to identify the role of polymorphisms in GSTT1 and GSTM1 genes in the risk of development of breast cancer, in the prognostication of breast cancer, and in the prediction of response towards chemotherapy. Ninety-nine patients with breast cancer and 100 healthy controls with no history of cancer were taken from blood donors after informed consent. Epidemiological and clinical data was collected from participants and 5 ml of peripheral venous blood was collected for genotype analysis. Null genotype of GSTT1 was detected in 51.04 % of the controls in comparison to 20.2 % of patients with carcinoma breast, which was found to be statistically significant (OR 4.18; 95 % CI 2.01-8.75; P = 0.0001). GSTM1 gene deletion was also significantly more common among controls (60 %) than in patients with breast cancer (33 %) (OR 4.57; 95 % CI 2.20-9.51; P = 0.0001). Tumors more than 5 cm in size had greater tendency for GSTM1 gene expression (P value = 0.019), but other clinicopathological parameters did not show any correlation. GSTT1 and GSTM1 genes status did not show any association with response to chemotherapy. The results indicated the null genotype of both GSTT1 and GSTM1 to be protective for the development of carcinoma breast. None of the known etiological factors have any correlation with GSTT1 and GSTM1 gene deletion. Patients with small tumor size expressed GSTM1 gene deletion. Other tumor characteristics and clinicopathological parameters did not have any correlation with gene deletion.

A prospective randomized controlled blinded study to evaluate the effect of short-term focused training program in laparoscopy on operating room performance of surgery residents (CTRI /2012/11/003113)

INTRODUCTION

Laparoscopic surgery requires certain specific skills. There have been several attempts to minimize the learning curve with training outside the operation room. Although simulators have been well validated as tools to teach technical skills, their integration into comprehensive curricula is lacking. Several randomized controlled trials and systematic reviews have demonstrated that the technical skills learned on these simulators transfer to the operating room. Currently, however, the integration of these simulated models into formal residency training curricula is lacking. In our institute, we have adopted the Tuebingen Trainer devised by Professor GF Buess from Germany. The purpose of this study was to evaluate the training of surgical residents on an ex vivo phantom model for basic laparoscopic skill acquisition and its transferability to the OR performance.

MATERIALS AND METHODS

Seventeen general surgery residents were randomized into 2 groups: Laparoscopic Training Group (n = 9, Group A) and Standard Training Group (n = 8, Group B). Group A underwent training in the Minimally Invasive Surgery Training Centre on the porcine phantom model and did 10 laparoscopic cholecystectomies, whereas Group B did not undergo training in the Minimally Invasive Surgery Training Centre. All the participants performed a laparoscopic cholecystectomy in the operation theater in the presence of a consultant who was blinded to the training status of the participants. The performance of the residents in both groups in the operation theater was assessed using GOALS criteria, surgical performance assessment parameters, task-specific checklists, and visual analog scale for gallbladder perforation difficulty and overall competence.

RESULTS

The Laparoscopic Training Group had better performance than the Standard Training Group regarding operation time, GOALS criteria, and Task-specific checklists. Although the surgical performance assessments, i.e. cystic duct and artery identification scores, gallbladder perforation scores, and liver injury scores, were better in the Laparoscopic Training Groups, they were not statistically significant. The overall difficulty of the surgery was comparable in both the groups. The Laparoscopic Training Group exhibited significant overall competence on visual analog scale scores.

CONCLUSION

Our study has clearly shown that training on the Tuebingen Trainer with integrated porcine organs results in a statistically significant improvement in the operating room performance of surgical residents as compared with the nontrained residents, thereby indicating a transfer of skills from training to the operating room.

Single-stage laparoscopic common bile duct exploration and cholecystectomy versus two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy for patients with concomitant gallbladder stones and common bile duct stones: a randomized controlled trial

BACKGROUND

The ideal method for managing concomitant gallbladder stones and common bile duct (CBD) stones is debatable. The currently preferred method is two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy (LC). This prospective randomized trial compared the success and cost effectiveness of single- and two-stage management of patients with concomitant gallbladder and CBD stones.

METHODS

Consecutive patients with concomitant gallbladder and CBD stones were randomized to either single-stage laparoscopic CBD exploration and cholecystectomy (group 1) or endoscopic retrograde cholangiopancreatography (ERCP) for endoscopic extraction of CBD stones followed by LC (group 2). Success was defined as complete clearance of CBD and cholecystectomy by the intended method. Cost effectiveness was measured using the incremental cost-effectiveness ratio. Intention-to-treat analysis was performed to compare outcomes.

RESULTS

From February 2009 to October 2012, 168 patients were randomized: 84 to the single-stage procedure (group 1) and 84 to the two-stage procedure (group 2). Both groups were matched with regard to demographic and clinical parameters. The success rates of laparoscopic CBD exploration and ERCP for clearance of CBD were similar (91.7 vs. 88.1 %). The overall success rate also was comparable: 88.1 % in group 1 and 79.8 % in group 2 (p = 0.20). Direct choledochotomy was performed in 83 of the 84 patients. The mean operative time was significantly longer in group 1 (135.7 ± 36.6 vs. 72.4 ± 27.6 min; p ≤ 0.001), but the overall hospital stay was significantly shorter (4.6 ± 2.4 vs. 5.3 ± 6.2 days; p = 0.03). Group 2 had a significantly greater number of procedures per patient (p < 0.001) and a higher cost (p = 0.002). The two groups did not differ significantly in terms of postoperative wound infection rates or major complications.

CONCLUSIONS

Single- and two-stage management for uncomplicated concomitant gallbladder and CBD stones had similar success and complication rates, but the single-stage strategy was better in terms of shorter hospital stay, need for fewer procedures, and cost effectiveness.

Laparoscopic suturing skills acquisition: a comparison between laparoscopy-exposed and laparoscopy-naive surgeons

This study suggests that training improves laparoscopic suturing skills in experienced as well as inexperienced laparoscopic surgeons.

Background:

Laparoscopic suturing is a difficult skill to master but can be acquired with extensive training outside the operating room. This study was done with the primary aim of assessing whether prior exposure to laparoscopic surgery helped trainees in acquiring laparoscopic suturing skills more quickly than trainees with no prior exposure to laparoscopic surgery.

Materials and Methods:

Twenty laparoscopy-exposed and 20 laparoscopy-naïve surgeons performed 5 laparoscopic gastrojejunostomies each on a phantom porcine model. The performance was evaluated for operation time, overall anastomotic score (calculated by adding scores of anastomotic leak, size of the anastomosis, suture placement, and mucosal approximation), and the level of difficulty. The performance at the beginning of training (baseline) was compared to the performance at the end of training.

Results:

All participants showed statistically significant improvement in operation time, overall anastomotic score, and difficulty level. Laparoscopy-exposed surgeons had a significantly better operation time than laparoscopy-naïve surgeons at the beginning of training; however, the difference became insignificant by the end of training. The difference in overall anastomotic score was not significant between laparoscopy-exposed and naïve-surgeons. Laparoscopy-exposed surgeons showed significant improvements in anastomotic leak rate and size of the anastomosis, whereas laparoscopy naïve surgeons showed improvements in all the parameters, although these were not significant statistically.

Conclusion:

Training improves the laparoscopic suturing skills of laparoscopy-exposed as well as laparoscopy-naïve surgeons. Prior experience in laparoscopic surgery does not seem to influence the acquisition of laparoscopic suturing skills as laparoscopic-naïve surgeons manage to catch up with the skills of the laparoscopy-exposed surgeons.

Accelerated gradient based diffuse optical tomographic image reconstruction

PURPOSE

Fast reconstruction of interior optical parameter distribution using a new approach called Broyden-based model iterative image reconstruction (BMOBIIR) and adjoint Broyden-based MOBIIR (ABMOBIIR) of a tissue and a tissue mimicking phantom from boundary measurement data in diffuse optical tomography (DOT).

METHODS

DOT is a nonlinear and ill-posed inverse problem. Newton-based MOBIIR algorithm, which is generally used, requires repeated evaluation of the Jacobian which consumes bulk of the computation time for reconstruction. In this study, we propose a Broyden approach-based accelerated scheme for Jacobian computation and it is combined with conjugate gradient scheme (CGS) for fast reconstruction. The method makes explicit use of secant and adjoint information that can be obtained from forward solution of the diffusion equation. This approach reduces the computational time many fold by approximating the system Jacobian successively through low-rank updates.

RESULTS

Simulation studies have been carried out with single as well as multiple inhomogeneities. Algorithms are validated using an experimental study carried out on a pork tissue with fat acting as an inhomogeneity. The results obtained through the proposed BMOBIIR and ABMOBIIR approaches are compared with those of Newton-based MOBIIR algorithm. The mean squared error and execution time are used as metrics for comparing the results of reconstruction.

CONCLUSIONS

We have shown through experimental and simulation studies that Broyden-based MOBIIR and adjoint Broyden-based methods are capable of reconstructing single as well as multiple inhomogeneities in tissue and a tissue-mimicking phantom. Broyden MOBIIR and adjoint Broyden MOBIIR methods are computationally simple and they result in much faster implementations because they avoid direct evaluation of Jacobian. The image reconstructions have been carried out with different initial values using Newton, Broyden, and adjoint Broyden approaches. These algorithms work well when the initial guess is close to the true solution. However, when initial guess is far away from true solution, Newton-based MOBIIR gives better reconstructed images. The proposed methods are found to be stable with noisy measurement data.

Technological Development for Commercialization of Amorphous Silicon Based Multijunction Modules

Some of the significant steps in technological development for large-scale commercialization of amorphous silicon (a-Si:H) based multijunction photovoltaic modules are presented. These developments are establishing a high quality baseline process for manufacturing large-area ( ˜ 8 ft2) a-Si:H/a-SiGe:H tandem junction modules with improved stabilized conversion efficiency, throughput, yield, and reduced materials usage.

Assessment of ultrasound modulation of near infrared light on the quantification of scattering coefficient

PURPOSE

To assess the effect of ultrasound modulation of near infrared (NIR) light on the quantification of scattering coefficient in tissue-mimicking biological phantoms.

METHODS

A unique method to estimate the phase of the modulated NIR light making use of only time averaged intensity measurements using a charge coupled device camera is used in this investigation. These experimental measurements from tissue-mimicking biological phantoms are used to estimate the differential pathlength, in turn leading to estimation of optical scattering coefficient. A Monte-Carlo model based numerical estimation of phase in lieu of ultrasound modulation is performed to verify the experimental results.

RESULTS

The results indicate that the ultrasound modulation of NIR light enhances the effective scattering coefficient. The observed effective scattering coefficient enhancement in tissue-mimicking viscoelastic phantoms increases with increasing ultrasound drive voltage. The same trend is noticed as the ultrasound modulation frequency approaches the natural vibration frequency of the phantom material. The contrast enhancement is less for the stiffer (larger storage modulus) tissue, mimicking tumor necrotic core, compared to the normal tissue.

CONCLUSIONS

The ultrasound modulation of the insonified region leads to an increase in the effective number of scattering events experienced by NIR light, increasing the measured phase, causing the enhancement in the effective scattering coefficient. The ultrasound modulation of NIR light could provide better estimation of scattering coefficient. The observed local enhancement of the effective scattering coefficient, in the ultrasound focal region, is validated using both experimental measurements and Monte-Carlo simulations.

Implementation of a phase array diffuse optical tomographic imager

Diffuse optical tomography (DOT) using near-infrared (NIR) light is a promising tool for noninvasive imaging of deep tissue. This technique is capable of quantitative reconstructions of absorption coefficient inhomogeneities of tissue. The motivation for reconstructing the optical property variation is that it, and, in particular, the absorption coefficient variation, can be used to diagnose different metabolic and disease states of tissue. In DOT, like any other medical imaging modality, the aim is to produce a reconstruction with good spatial resolution and accuracy from noisy measurements. We study the performance of a phase array system for detection of optical inhomogeneities in tissue. The light transport through a tissue is diffusive in nature and can be modeled using diffusion equation if the optical parameters of the inhomogeneity are close to the optical properties of the background. The amplitude cancellation method that uses dual out-of-phase sources (phase array) can detect and locate small objects in turbid medium. The inverse problem is solved using model based iterative image reconstruction. Diffusion equation is solved using finite element method for providing the forward model for photon transport. The solution of the forward problem is used for computing the Jacobian and the simultaneous equation is solved using conjugate gradient search. The simulation studies have been carried out and the results show that a phase array system can resolve inhomogeneities with sizes of 5 mm when the absorption coefficient of the inhomogeneity is twice that of the background tissue. To validate this result, a prototype model for performing a dual-source system has been developed. Experiments are carried out by inserting an inhomogeneity of high optical absorption coefficient in an otherwise homogeneous phantom while keeping the scattering coefficient same. The high frequency (100 MHz) modulated dual out-of-phase laser source light is propagated through the phantom. The interference of these sources creates an amplitude null and a phase shift of 180 degrees along a plane between the two sources with a homogeneous object. A solid resin phantom with inhomogeneities simulating the tumor is used in our experiment. The amplitude and phase changes are found to be disturbed by the presence of the inhomogeneity in the object. The experimental data (amplitude and the phase measured at the detector) are used for reconstruction. The results show that the method is able to detect multiple inhomogeneities with sizes of 4 mm. The localization error for a 5 mm inhomogeneity is found to be approximately 1 mm.

Computational experience with a parallel algorithm for tetrangle inequality bound smoothing

Determining molecular structure from interatomic distances is an important and challenging problem. Given a molecule with n atoms, lower and upper bounds on interatomic distances can usually be obtained only for a small subset of the 2(n(n-1)) atom pairs, using NMR. Given the bounds so obtained on the distances between some of the atom pairs, it is often useful to compute tighter bounds on all the 2(n(n-1)) pairwise distances. This process is referred to as bound smoothing. The initial lower and upper bounds for the pairwise distances not measured are usually assumed to be 0 and infinity. One method for bound smoothing is to use the limits imposed by the triangle inequality. The distance bounds so obtained can often be tightened further by applying the tetrangle inequality--the limits imposed on the six pairwise distances among a set of four atoms (instead of three for the triangle inequalities). The tetrangle inequality is expressed by the Cayley-Menger determinants. For every quadruple of atoms, each pass of the tetrangle inequality bound smoothing procedure finds upper and lower limits on each of the six distances in the quadruple. Applying the tetrangle inequalities to each of the (4n) quadruples requires O(n4) time. Here, we propose a parallel algorithm for bound smoothing employing the tetrangle inequality. Each pass of our algorithm requires O(n3 log n) time on a REW PRAM (Concurrent Read Exclusive Write Parallel Random Access Machine) with O(log(n)n) processors. An implementation of this parallel algorithm on the Intel Paragon XP/S and its performance are also discussed.

Filter for biomedical imaging and image processing

Image filtering techniques have numerous potential applications in biomedical imaging and image processing. The design of filters largely depends on the a priori, knowledge about the type of noise corrupting the image. This makes the standard filters application specific. Widely used filters such as average, Gaussian, and Wiener reduce noisy artifacts by smoothing. However, this operation normally results in smoothing of the edges as well. On the other hand, sharpening filters enhance the high-frequency details, making the image nonsmooth. An integrated general approach to design a finite impulse response filter based on Hebbian learning is proposed for optimal image filtering. This algorithm exploits the interpixel correlation by updating the filter coefficients using Hebbian learning. The algorithm is made iterative for achieving efficient learning from the neighborhood pixels. This algorithm performs optimal smoothing of the noisy image by preserving high-frequency as well as low-frequency features. Evaluation results show that the proposed finite impulse response filter is robust under various noise distributions such as Gaussian noise, salt-and-pepper noise, and speckle noise. Furthermore, the proposed approach does not require any a priori knowledge about the type of noise. The number of unknown parameters is few, and most of these parameters are adaptively obtained from the processed image. The proposed filter is successfully applied for image reconstruction in a positron emission tomography imaging modality. The images reconstructed by the proposed algorithm are found to be superior in quality compared with those reconstructed by existing PET image reconstruction methodologies.

Kynurenate treatment of autaptic hippocampal microcultures affect localized voltage-dependent calcium diffusion in the dendrites

It is not clear how different spatial compartments in the neuron are affected during epileptiform activity. In the present study we have examined the spatial and temporal profiles of depolarization induced changes in the intracellular Ca(2+) concentration in the dendrites of cultured autaptic hippocampal pyramidal neurons rendered epileptic experimentally by treatment with kynurenate (2 mM) and Mg(2+) (11.3 mM) in culture (treated neurons). This was examined with simultaneous somatic patch-pipette recording and Ca(2+) imaging experiments using the Ca(2+) indicator Oregon Green 488 BAPTA-1. Neurons stimulated by depolarization under whole-cell voltage clamp conditions revealed Ca(2+) entry at localized sites in the dendrites. Ca(2+) transients were observed even in the presence of NMDA and AMPA receptor antagonists suggesting that the opening of voltage gated calcium channels primarily triggered the local Ca(2+) changes. Peak Ca(2+) transients in the dendrites of treated neurons were larger compared to the signals recorded from the control neurons. Dendritic Ca(2+) transients in treated neurons showed a distance dependent scaling. Estimation of dendritic local Ca(2+) diffusion coefficients indicated higher values in the treated neurons and a higher availability of free Ca(2+). Simulation studies of Ca(2+) dynamics in these localized dendritic compartments indicate that local Ca(2+) buffering and removal mechanisms may be affected in treated neurons. Our studies indicate that small dendritic compartments are rendered more vulnerable to changes in intracellular Ca(2+) following induction of epileptiform activity. This can have important cellular consequences including local membrane excitability through mechanisms that remain to be elucidated.

Fuzzy-rule-based image reconstruction for positron emission tomography

Positron emission tomography (PET) and single-photon emission computed tomography have revolutionized the field of medicine and biology. Penalized iterative algorithms based on maximum a posteriori (MAP) estimation eliminate noisy artifacts by utilizing available prior information in the reconstruction process but often result in a blurring effect. MAP-based algorithms fail to determine the density class in the reconstructed image and hence penalize the pixels irrespective of the density class. Reconstruction with better edge information is often difficult because prior knowledge is not taken into account. The recently introduced median-root-prior (MRP)-based algorithm preserves the edges, but a steplike streaking effect is observed in the reconstructed image, which is undesirable. A fuzzy approach is proposed for modeling the nature of interpixel interaction in order to build an artifact-free edge-preserving reconstruction. The proposed algorithm consists of two elementary steps: (1) edge detection, in which fuzzy-rule-based derivatives are used for the detection of edges in the nearest neighborhood window (which is equivalent to recognizing nearby density classes), and (2) fuzzy smoothing, in which penalization is performed only for those pixels for which no edge is detected in the nearest neighborhood. Both of these operations are carried out iteratively until the image converges. Analysis shows that the proposed fuzzy-rule-based reconstruction algorithm is capable of producing qualitatively better reconstructed images than those reconstructed by MAP and MR P algorithms. The reconstructed images a resharper, with small features being better resolved owing to the nature of the fuzzy potential function.

Modeling and simulation for phase coarsening: a comparison with experiment

The phase coarsening of precipitates is modeled in the framework of Debye-Hückel theory. The interactions observed among a population of precipitates dispersed throughout a matrix can be described by diffusion screening. The relationship between the maximum particle radius and the volume fraction of the phases is established, and the rate of coarsening is related to the volume fraction and the self-similar particle size distribution. We simulated the dynamics of late-stage phase separation using multiparticle diffusion methods. Experimental measurements on the rates of coarsening of delta(') ( Al3 Li) precipitates in binary Al-Li alloys are compared with our results using modeling and simulation. The theoretically predicted particle size distributions and the maximum radius expected for particles in the microstructure agree well with recent experimental results.

A double-blind, placebo-controlled study of the efficacy of oral penicillin, diethylcarbamazine or local treatment of the affected limb in preventing acute adenolymphangitis in lymphoedema caused by brugian filariasis

Acute attacks of adenolymphangitis (ADL) contribute significantly to the morbidity seen in cases of filarial lymphoedema. Such cases are now being treated with multiple courses of the antifilarial drug diethylcarbamazine (DEC), either alone or in combination with antibiotics or anti-inflammatory drugs, based on anecdotal experience. In this, the first double-blind, placebo-controlled study, 150 patients with lymphoedema caused by brugian filariasis, each of whom recalled two or more ADL attacks in the previous year, were enrolled on a comprehensive foot-care programme. Each was also randomly allocated to one of the following five daily regimens (30 patients/regimen) for 1 year: 800 mg oral penicillin; 1 mg DEC/kg; 800 mg oral penicillin plus 1 mg DEC/kg; local antibiotics; or placebo. Each patient was followed up for another year. For each regimen group (including the placebo group), the number of ADL attacks in the treatment year was significantly less than that in the year prior to treatment (P < 0.001). Although, in all but the placebo group, there was a slight increase in the number of episodes in the follow-up year compared with the treatment year, the increase was only significant in the two groups given penicillin. Of all the treatments tested therefore, foot care seems to play the most important role in the prevention of ADL attacks. Additional benefit may accrue from local or systemic antibiotic use in those with high grades of oedema, but antifilarials have no place in the prevention of ADL attacks in an individual patient. These observations should help in the rational management and prevention of ADL attacks in filarial lymphoedema, so that the progression of the disease may be halted and morbidity reduced.

Prevention of acute adenolymphangitis in brugian filariasis: comparison of the efficacy of ivermectin and diethylcarbamazine, each combined with local treatment of the affected limb

Acute attacks of adenolymphangitis (ADL) not only force patients with lymphatic filariasis to seek medical attention but also hasten the progression of filarial oedema. Patients with filariasis-associated ADL are currently treated with repeated courses of the antifilarial drug diethylcarbamazine (DEC), with or without antibiotics and anti-inflammatory agents. In this double-blind, placebo-controlled study, the efficacy of local treatment of the affected limb combined with repeated doses of ivermectin or DEC, in preventing the occurrence of ADL in Brugia malayi lymphatic filariasis, was examined. Overall, 120 patients who had each had at least two ADL attacks in the previous year were each admitted to the study at the time of an ongoing episode of ADL. The patients were randomly allocated to receive 12, monthly treatments of ivermectin (400 micrograms/kg), DEC (10 mg/kg) or placebo, in addition to local care of the affected limbs. There was a significant reduction in the frequency of ADL attacks in each of the three groups during the 2-year study period (P < 0.001 for each comparison). Most importantly, there were no significant differences in frequency of attacks between the three groups, either at the end of the treatment phase or at the end of the post-treatment phase (P > 0.15 for each comparison), suggesting that foot care combined with appropriate use of local antibiotics or antifungals is adequate to reduce the number of ADL attacks. The implications of these observations for planning morbidity control in lymphatic filariasis are discussed.

A comparative study of the efficacy and tolerability of single and split doses of ivermectin and diethylcarbamazine in periodic brugian filariasis

The use of ivermectin in lymphatic filariasis (both bancroftian and brugian) has been recently explored in several studies. We report in this paper, for the first time, a direct comparison of the efficacy and tolerability of single doses of ivermectin and diethylcarbamazine (DEC) in brugian filariasis. We also present our findings on the use of split doses of ivermectin and DEC on microfilaraemia levels and the occurrence of adverse reactions. Fifty male, asymptomatic microfilaremics drawn from the Alleppey District, Kerala, India, were allocated one of the following five treatment regimens in a double blind randomized study: (1) single oral 6 mg/kg dose of DEC; (2) single oral 6 mg/kg dose of DEC preceded by 1 mg/kg DEC primer; (3) single oral 220 micrograms/kg dose of ivermectin; (4) single oral 200 micrograms/kg dose of ivermectin preceded by a 20 micrograms/kg ivermectin primer; or (5) a single oral 400 micrograms/kg dose of ivermectin preceded by a 20 micrograms/kg ivermectin primer. The kinetics of microfilaria clearance differed in the two (DEC/ivermectin) groups in the first month post-treatment. At the end of 1 year there were no differences in the microfilaria levels in the two DEC-tested groups and the 420 micrograms/kg ivermectin group. The safety of the 400 micrograms/kg dose of ivermectin was established in this study which has also shown that, currently, this dose would be the best choice for brugian filariasis. Patients in the ivermectin groups had significantly lower adverse reaction scores than patients who had received DEC. There was no advantage in splitting the dose of either DEC or ivermectin, either in terms of efficacy or tolerability.(ABSTRACT TRUNCATED AT 250 WORDS)

Ivermectin for the treatment of periodic malayan filariasis: a study of efficacy and side effects following a single oral dose and retreatment at six months

Ivermectin, a new antifilarial drug and currently the drug of choice for the treatment of onchocerciasis, has been shown to be effective in bancroftian filariasis. We report here, for the first time, the efficacy and safety of the drug in the treatment of filariasis caused by periodic Brugia malayi. Sixty male, asymptomatic microfilaraemics of Alleppey district, Kerala, South India, received single oral doses of ivermectin in a double blind study. Four dosages were used: 20, 50, 100 and 200 micrograms kg-1 body weight. Clearance of microfilariae, which was not complete, began as early as 12 hours post-treatment and was maximal at the end of one month. Microfilaria levels began to rise thereafter and reached 20-50% of pretreatment levels at six months. The two higher doses (100 and 200 micrograms kg-1) were more effective in suppressing microfilaraemia at six months (P < 0.05). After six months, 32 patients were retreated using the same dose of ivermectin that they had received initially. The pattern of clearance was essentially similar to that seen during the first treatment phase and microfilaria levels were 10-35% of pretreatment levels at the end of the next six months. Twenty-eight individuals who were not retreated at six months continued to have increasing levels of microfilariae, reaching 60% of pretreatment levels at the end of the next six months. Side effects (such as fever, headache, myalgia), which were mild to moderate, were seen in most patients and were unrelated to the dose (P > 0.05) or pretreatment levels of microfilariae.(ABSTRACT TRUNCATED AT 250 WORDS)

Attitudes to smoking and smoking habit among the staff of a hospital

A survey of the smoking habits and attitudes towards smoking of all staff working in a teaching hospital with a specialist thoracic department has been carried out. Six hundred and sixty three (70%) of the 949 members of staff returned a voluntary self completed questionnaire. Completion rates were highest among medical, administrative, and clerical staff, and lowest among domestic and catering staff. Of the 663 responders, 136 (23%) admitted to being current smokers and 135 (19%) to being ex-smokers. The great majority of responders (81-94%, depending on area of work) believed that more areas of the hospital should be entirely smoking free. Most responders, however, believed that some accommodation should be made available to staff (70%), patients (52%), or visitors (59%) who wished to smoke. About a quarter of smokers expressed interest in joining a group to help them give up smoking.