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PubMed1996

Immunoelectrochemical assays for bacteria: use of epifluorescence microscopy and rapid-scan electrochemical techniques in development of an assay for Salmonella.

Immunoelectrochemical sensors in which the sensor surface functions as both analyte capture phase and electrochemical detector have recently been developed for bacteria analysis. The speed and sensitivity of these devices make them very attractive for applications such as the detection of pathogenic microorganisms in food and water. However, the development and optimization of assays utilizing these sensors can be complicated by undesired interactions between the capture and detection functions. Modification of the sensor to achieve improvements in one function can have deleterious effects on the other function, and such effects can be difficult to diagnose and correct. In the course of investigations on immunoelectrochemical detection of Salmonella, we developed a rapid, nondestructive epifluorescence microscopy method to determine bacteria capture efficiency. This method enabled us to study capture and detection functions independently and efficiently identify performance-limiting factors. Rapid-scan electrochemical methods were used to optimize detection sensitivity and to provide diagnostic information on detection performance.

Electrochemistry↗
PubMed2002

Prosodic control in severe dysarthria: preserved ability to mark the question-statement contrast.

Speakers with severe dysarthria are known to have reduced range in prosody. Consistent control within that range, however, has largely been ignored. In earlier investigations speakers with severe dysarthria were able to control pitch and duration for sustained vowel production despite reduced flexibility of control (Patel, 1998). The present experiment examined whether 8 speakers with severe dysarthria due to cerebral palsy used prosodic parameters of pitch contour and syllable duration for phrase-level productions. Speakers with dysarthria (N = 8) produced 3-syllable phrases as questions and statements. Naïve listeners (N = 48) classifed dysarthric productions as either questions or statements. Listeners were able to distinguish questions from statements with accuracy levels ranging from 81% to 98%. We were also interested in studying how dysorthric speakers marked the question-statement contrast. Prosodic features of pitch contour and syllable duration were systematically removed from the original recorded vocalizations to examine the salience of these features on listener classification. Removal of pitch contour cues dramatically reduced listener accuracy scores to almost chance performance. Listeners found pitch contour cues to be information-bearing cues in dysarthric vocalizations even though the range of frequency control in these speakers may be reduced. That speakers with dysarthria were able to exert sufficient control to signal the question-statement contrast has implications for diagnostic and intervention practices aimed to optimally exploit prosodic control for enhancing communication efficiency.

Adult↗
PubMed2004

Current understanding and management of allograft vasculopathy.

Cardiac allograft vasculopathy (CAV) is the major obstacle to long-term survival after heart transplantation. It is a rapidly progressive, obliterative form of coronary vasculopathy distinct from classic atheromatous disease. The pathogenesis is most likely multifactorial and involves both alloantigen dependent and independent mechanisms. Since there is no definitive treatment for CAV and new immunosuppressive agents can only slow the progression of this disease, the prophylaxis and modification of numerous risk factors remains the foundation of posttransplant management in the heart transplant recipient. In this review, we discuss current understanding of the pathogenesis of CAV, novel diagnostic and therapeutic avenues and explore optimal approaches to risk factors modification.

Coronary Disease↗
PubMed2002

Pattern recognition technique in immunological antigenic tests to identify Mycobacterium tuberculosis infection.

UNLABELLED: The importance of a diagnostic test that is simple and quick to identify Mycobacterium tuberculosis infection needs no emphasis. The tuberculin skin test (TST - 1 TU RT23) is the diagnostic tool for identifying M. tuberculosis infection at present. The test reaction on the skin is measured after 48-72 h. It is observed that often multi-modes are seen, when the reactions are drawn as a graph and the bimodality is seen very feebly. Because of the difficulties in the administration of TST, several serological tests were developed over three decades, but none of the studies showed the desired results. One study to evaluate purified protein derivative (PPD) antigen resulted in a claim of 80% sensitivity and 4% false-positivity rate (14), while other researchers were not able to obtain similar results. In addition, several problems were encountered due to the non-availability of antigens, and data analyses from an ELISA-based diagnostic test showed considerable overlap of distributions of optical density (OD) values among patients and healthy individuals (10). Classical statistical techniques cannot explain the cause of these overlaps. Hence, an attempt is made in this article to resolve these difficulties by the pattern recognition technique (PRT). The technique lies in splitting the data into clusters using a supervised algorithm. The data set is normally split into a training set, a test set and a validation set. The PRT gets "trained" through the training data set until the infected and uninfected groups of individuals are correctly classified. The training occurs based on an algorithm on the training set. On successful completion of the training, this technique is further tested and validated in the respective data sets. SETTING: A total of 273 finger-prick specimens were collected from five categories (Al, A2, B, C, D, E) of subjects not vaccinated with (bacille Calmette Guerin) (BCG) from Trivellore BCG Trial area adopted by the Tuberculosis Research Center, Chennai, India. OBJECTIVE: The study was conducted with the primary aim of evaluating purified antigens--r38 kDa, PPD and 30 kDa--for their usefulness as diagnostic tools and to test the applicability of the PRT in the evaluation of diagnostic tests. Individuals in two main categories (definitely not infected categories Al, A2 and D, and definitely infected categories B, E and C based on reaction to TST) were assembled for the purpose. RESULTS: The overall PRT performance of 30 kDa was 72.3% sensitivity and 90.9% specificity for identifying M. tuberculosis infection, while the r38 kDa antigen recorded a sensitivity of 73.8% and a specificity of 84.6%. In the case of PPD, the results were not promising. CONCLUSION: This paper on ELISA-based diagnostic tests attempts to implement an optimal decision support system through PRT that would identify the outcome (as infected or non-infected) based on the OD values. The PRT was able to predict the outcome for individual suspects. Further, Kullback-Leibler distance measurement has validated the PRT in distinguishing infected individuals from healthy subjects (based on the OD values).

Adolescent↗
PubMed2004

Familial hypercholesterolemia in Spain: case-finding program, clinical and genetic aspects.

A case-finding program for the identification of patients with familial hypercholesterolemia (FH) has been established in Spain. The program is based on family investigation and molecular genetic testing for mutations in the low-density lipoprotein receptor gene. To assist this program, intensive research into the molecular basis of FH and genotype/phenotype relations is performed. To optimize DNA testing, a DNA-diagnostic platform has been constructed that is composed of systematic mutation screening by single-strand conformation polymorphism (SSCP) analysis, DNA-sequencing, Southern blotting, and the use of microarrays for high-throughput analysis. To date, 161 different mutations leading to inherited hypercholesterolemia have been identified in Spanish patients with FH. In addition, a patient organization was founded to ensure patient support and follow-up. To further facilitate FH case-finding and patient follow-up, we initiated the publication of a set of guidelines for diagnosis and clinical management of FH that can be applied internationally.

DNA Mutational Analysis↗
PubMed2006

The use of self-expanding metal stents to treat acute esophageal variceal bleeding.

BACKGROUND AND STUDY AIMS: Acute variceal bleeding is a life-threatening complication of liver cirrhosis. Essential factors for survival after variceal bleeding are the rapidity and efficacy of initial primary hemostasis. Endoscopic and vasoactive therapy is the gold standard in the management of acute variceal hemorrhage. The primary aim of this study was to evaluate the use of self-expandable metallic stents to arrest uncontrollable acute variceal bleeding. PATIENTS AND METHODS: Between November 2002 and May 2005, esophageal stents were implanted in 20 patients (18 men, two women; mean age 52, range 27-87) with massive ongoing bleeding from esophageal varices, as an alternative treatment to balloon tamponade. The patients had not been successfully managed with prior pharmacologic or endoscopic therapy. They had had one to five previous bleeding episodes (mean 2.4). Eight of the patients were in Child-Pugh grade B and 12 in grade C. A new type of stent with special introducers was developed that allowed placement without radiographic assistance. RESULTS: The stents were successfully placed in all of the patients and were left in place for 2-14 days. Bleeding from the esophageal varices ceased immediately after implantation of the stent in all cases. While the stent was in place, further diagnostic steps were carried out to optimize management of the patients' illness and portal hypertension. No recurrent bleeding, morbidity, or mortality occurred during treatment with the esophageal stent. All of the stents were extracted without any complications after definitive treatment had been started. CONCLUSIONS: In this pilot study, the new method of implantation of an esophageal stent was found to be a safe and effective treatment for massive bleeding from esophageal varices in patients with liver cirrhosis. These initial clinical results will of course have to be confirmed in comparative studies including a large number of patients.

Acute Disease↗
PubMed1988

Carcinoma of the ampulla of Vater: the endoscopic approach.

Carcinoma of the ampulla of Vater is a rare tumor. Early and accurate diagnosis of carcinoma of the ampulla of Vater will lead to early treatment and subsequent better prognosis. Endoscopy and endoscopic retrograde cholangiopancreaticography (ERCP) has been shown to be one of the best diagnostic modalities. Furthermore an endoscopic biliary drainage procedure can be performed immediately following the diagnostic procedure. The tumors may be seen as large, fleshy, friable exophytic growths, as ulcerated tumors into the duodenal wall or as a mass behind the orifice of the papilla, covered with normal duodenal mucosa. Forceps biopsies do not always suffice to show malignancy. Large snare biopsies often are necessary. Occasionally the final diagnosis of malignancy can only be made by examination of the surgical resection specimen. Tumors arising inside the ampulla form a bulge, covered by normal duodenal mucosa. An impacted stone may mimic this picture. Endoscopic papillotomy is then mandatory to make the final diagnosis. Histologic examination of forceps biopsies reveals malignancy in only 60% of cases. When snare biopsy is used, the diagnostic yield increases to 83%. The optimal treatment of carcinomas of the ampulla of Vater is surgical resection. Preoperative biliary drainage should theoretically be of benefit to the patient. The results of preoperative percutaneous drainage studies are, however, conflicting. Carcinoma of the ampulla of Vater is not resectable in 25-50% of the patients because of metastatic disease, deep extension of the tumor or general contraindications for major surgery. Endoscopic papillotomy or stent placement as a definitive treatment modality should be reserved for poor surgical candidates and for those patients with limited life expectancy due to metastatic disease.

Ampulla of Vater↗
PubMed1982

[The "false-positive polyp" during contrast examination of the colon (author's transl)].

44 cases of false-positive radiological diagnosis of colonic polyps are reviewed with regard to cause, frequency, distribution and radiological criteria. Most common causes are scybala and air bubbles (77%) and effects of overlapping and projection (19%). Due to extensive folding of the colon misinterpretations are frequently seen in the sigmoid and in the area of both flexures; the folding allows overlapping of mucosal structures and trapping of bowel contents. The validity of roentgen signs in polyp diagnosis and the limits of colonoscopy are discussed. Diagnostic reliability may be improved by optimal technique of examination and standardized proceeding.

Colonic Neoplasms↗
PubMedDate not supplied

Assessment of myocardial viability in dysfunctional myocardium by resting myocardial blood flow determined with oxygen 15 water PET.

BACKGROUND: There is controversy about the role of decreased resting blood flow as the pathophysiologic correlate of hibernating myocardium. The aim of this study was an absolute quantification of volumetric myocardial blood flow (MBFvol) in dysfunctional myocardium with different viability conditions as defined by fluorine 18 deoxyglucose (FDG) positron emission tomography (PET) while taking into consideration the functional recovery after revascularization. The impact of MBFvol in the diagnosis of functional recovery was also investigated. METHODS AND RESULTS: Forty-two patients with severe coronary artery disease and dysfunctional myocardium underwent resting oxygen 15 water PET, as well as FDG PET and technetium 99m tetrofosmin single photon emission computed tomography, all attenuation-corrected. Relative FDG and Tc-99m tetrofosmin uptake (normalized to the segment with 100% Tc-99m tetrofosmin uptake), as well as MBFvol (myocardial blood flow multiplied by the water-perfusable tissue fraction to account for the flow to the entire segment volume), were determined in 18 myocardial segments per patient. Viability in dysfunctional segments (estimated by ventriculography) with reduced Tc-99m tetrofosmin uptake of 70% or lower was classified as viable (FDG >70%, mismatch) or nonviable (FDG < or =70%, match). Fifteen patients underwent revascularization and were followed up. Mismatch segments with improved function were classified as hibernating myocardium. Mean MBFvol in viable myocardium was slightly reduced (0.60 +/- 0.02 mL x min(-1) x mL(-1)) compared with that in normokinetic myocardium (0.64 +/- 0.01 mL x min(-1) x mL(-1)) (P = .036) and was significantly higher than in nonviable myocardium (0.36 +/- 0.01 mL x min(-1) x mL(-1)) (P < .001). Receiver operating characteristic analysis confirmed an FDG uptake greater than 70% as the optimal threshold to predict functional recovery (diagnostic accuracy [ACC], 76%). MBFvol in hibernating myocardium (0.62 +/- 0.04 mL x min(-1) x mL(-1)) was not significantly reduced compared with that in normokinetic myocardium (0.66 +/- 0.02 mL x min(-1) x mL(-1)) and was significantly higher than in persistently dysfunctional myocardium (0.51 +/- 0.04 mL x min(-1) x mL(-1)) (P < .05). The ACC of MBFvol greater than 0.40 mL x min(-1) x mL(-1) as the threshold to predict functional recovery was 61% but did not improve the accuracy of FDG PET by itself. CONCLUSIONS: In patients with severe coronary artery disease and dysfunctional myocardium, MBFvol as determined with O-15 water differs significantly between viable and nonviable myocardium as determined by FDG PET and is not significantly reduced in hibernating compared with normokinetic myocardium. Therefore chronically reduced resting blood flow appears unlikely to be the pathophysiologic correlate of the functional state of hibernation. However, MBFvol does not improve the ACC of FDG PET by itself.

Adult↗
PubMed2005

An automated genotyping system for analysis of HIV-1 and other microbial sequences.

MOTIVATION: Genetic analysis of HIV-1 is important not only for vaccine development, but also to guide treatment strategies, track the emergence of new viral variants and ensure that diagnostic assays are contemporary and fully optimized. However, most genotyping methods are laborious and complex, and involve the use of multiple software applications. Here, we describe the development of an automated genotyping system that can be easily applied to HIV-1 and other rapidly evolving viral pathogens. RESULTS: The new REGA subtyping tool, developed using Java programming and PERL scripts, combines phylogenetic analyses with boot-scanning methods for the genetic subtyping of full-length and subgenomic fragments of HIV-1. When used to investigate the subtype of previously published reference datasets that were analysed using manual phylogenetic methods, the automated method correctly identified 97.5-100% of non-recombinant and circulating recombinant forms of HIV-1, including 108 full-length, 108 gag and 221 env sequences downloaded from the Los Alamos database.

Algorithms↗
PubMed2001

Small peptide GP IIb/IIIa receptor inhibitors as upstream therapy in non-ST-segment elevation acute coronary syndromes: results of the PURSUIT, PRISM, PRISM-PLUS, TACTICS, and PARAGON trials.

The primary pathophysiologic mechanism underlying all non-ST-segment elevation acute coronary syndromes (NSTE ACS) is the formation of platelet-rich coronary thrombi in response to spontaneous or intervention-induced endothelial damage with exposure of subendothelial substrates. Antagonists of the glycoprotein (GP) IIb/IIIa receptor ameliorate this process by blocking the final common pathway for platelet aggregation. Based upon collective data in over 24,000 patients, clinical trials have demonstrated that treatment of NSTE ACS patients with GP IIb/IIIa agents results in an approximate 12% relative risk reduction in the incidence of death or myocardial infarction at 30 days. The magnitude of this clinical benefit is increased in patients who are troponin-positive and who are referred for early percutaneous intervention. Potential benefits of GP IIb/IIIa inhibitor use must be weighed against an increased risk of bleeding. Ongoing controversies exist concerning the relative efficacy of different GP IIb/IIIa antagonists, the accurate use of platelet function tests to define safe and efficacious drug dosing, the adjunctive use of additional anti-thrombotic agents, and the optimal timing of upstream therapy before diagnostic cardiac catheterization and revascularization.

Acetates↗
PubMed1996

Saline infusion sonohysterography.

Saline infusion sonography enhances endovaginal ultrasound examination of the uterine cavity. It is easily and rapidly performed at minimal cost. It is well tolerated by patients and virtually devoid of complications. It can prevent further invasive diagnostic procedures in some patients and optimize the preoperative triage process for those patients who will require therapeutic intervention.

Administration, Intravaginal↗
PubMed2002

Optimization of contrast dosage for gadobenate dimeglumine-enhanced high-resolution whole-body 3D magnetic resonance angiography.

RATIONALE AND OBJECTIVES: To determine the optimal dose of gadobenate dimeglumine for diagnostic high-resolution whole-body 3D-MR angiography. METHODS: Ten healthy volunteers were examined three times with an ascending dose of Gd-BOPTA (0.1/0.2/0.3 mmol/kg BW). Three-dimensional data sets were collected with a rolling table platform (AngioSURF; MR-Innovation GmbH, Essen, Germany) which integrates the torso surface coil, using a 3D FLASH sequence at five stations from carotid arteries to the trifurcation vessels in 72 seconds. SNR- and contrast-to-noise-values were calculated for 30 segments per patient. For qualitative evaluation a 4-point-visualization scale was used. RESULTS: Overall, significantly (P < 0.05) higher signal-to-noise values and CNR values were determined for Gd-BOPTA at a dose of 0.2 and 0.3 mmol/kg compared with 0.1 mmol/kg. Similarly, the qualitative analysis demonstrated image quality to be superior with 0.2 and 0.3 mmol/kg compared with 0.1 mmol/kg (P < 0.05). Qualitative and quantitative assessment failed to demonstrate a statistically significant difference between 0.2 and 0.3 mmol/kg BW (P > 0.05). CONCLUSION: A dose of 0.2 mmol/kg BW Gd-BOPTA rendered diagnostic image quality in all vascular segments of all volunteers.

Adult↗
PubMed1977

Interdiagnosis relationships of physician performance measures in hospitals.

Correlations among ten diagnostic categories of hospital care physican performance measures are reported. Using measures of conformance to predetermined criteria for optimal performance, mean scores of individual physican performances within diagnostic categories were calculated and correlated. Measurement reliability estimates were computed and it was suggested that a minimum of four cases in each diagnostic category be used for measurement of performance on the individual physician level of analysis. There appeared to be homogeneity of performance measures among some but not all diagnoses studied. This finding reinforces the need to examine interdiagnostic correlations before attempting to measure overall individual physican performance by combining measures from separate diagnostic categories.

Acute Disease↗
PubMed1999

A new transfacial approach for lesions of the clivus and parapharyngeal space: the partial segmented Le Fort I osteotomy.

Tumors of the clival and parapharyngeal areas are a challenge because of their location. They used to be considered inaccessible because the aggressive approaches employed caused elevated levels of morbidity. This fact led to more conservative approaches that attempted to preserve the exposure of the lesion. These approaches were a combination of cranial and facial procedures, thus utilizing a combined effort between neurosurgeons and maxillofacial surgeons. We described our experience with a partial segmented Le Fort I osteotomy added to a transmandibular approach to expose a chordoma of the clivus and left parapharyngeal space. A three-dimensional imaging was used as a diagnostic tool and to plan the optimal surgical approach. The operative technique was described in this case study. Some important technical details of the approach are described. The global outcome was favorable.

Adult↗
PubMed2001

Hematogenous pyogenic facet joint infection.

STUDY DESIGN: Retrospective. OBJECTIVES: To determine the incidence, clinical presentation, diagnostic laboratory values, imaging characteristics, and optimal treatment of hematogenous pyogenic facet joint infections. SUMMARY OF BACKGROUND DATA: There are 27 documented cases of hematogenous pyogenic facet joint infections. Data regarding incidence, clinical presentation, diagnosis, and treatment response are incomplete because of the paucity of reported cases. METHODS: This is a retrospective study of all cases of hematogenous pyogenic facet joint infection treated at one institution. Data from previous publications were combined with the present series to identify pertinent clinical characteristics and response to treatment. RESULTS: A total of six cases (4%) of hematogenous pyogenic facet joint infection were identified of 140 cases of hematogenous pyogenic spinal infection at our institution. Combining all reported cases reveals the following: The average patient age is 55 years. Ninety-seven percent of cases occur in the lumbar spine. Epidural abscess formation complicates 25% of the cases of which 38% develop severe neurologic deficit. Erythrocyte sedimentation rate and C-reactive protein are elevated in all cases. Staphylococcus aureus is the most common infecting organism. Magnetic resonance imaging is accurate in identifying the septic joint and associated abscess formation. Percutaneous drainage of the involved joint has a higher rate of success (85%) than treatment with antibiotics alone (71%), but the difference is not significant (P = 0.37). CONCLUSIONS: Hematogenous pyogenic facet joint infection is a rare but underdiagnosed clinical entity. Facet joint infections may be complicated by abscess formation in the epidural space or in the paraspinal muscles. Uncomplicated cases treated with percutaneous drainage and antibiotics may fare better than those treated with antibiotics alone. Cases complicated by an epidural abscess and severe neurologic deficit should undergo immediate decompressive laminectomy.

Aged↗
PubMed2006

Tomographic reconstruction using an adaptive tetrahedral mesh defined by a point cloud.

Medical images in nuclear medicine are commonly represented in three dimensions as a stack of two-dimensional images that are reconstructed from tomographic projections. Although natural and straightforward, this may not be an optimal visual representation for performing various diagnostic tasks. A method for three-dimensional (3-D) tomographic reconstruction is developed using a point cloud image representation. A point cloud is a set of points (nodes) in space, where each node of the point cloud is characterized by its position and intensity. The density of the nodes determines the local resolution allowing for the modeling of different parts of the image with different resolution. The reconstructed volume, which in general could be of any resolution, size, shape, and topology, is represented by a set of nonoverlapping tetrahedra defined by the nodes. The intensity at any point within the volume is defined by linearly interpolating inside a tetrahedron from the values at the four nodes that define the tetrahedron. This approach creates a continuous piecewise linear intensity over the reconstruction domain. The reconstruction provides a distinct multiresolution representation, which is designed to accurately and efficiently represent the 3-D image. The method is applicable to the acquisition of any tomographic geometry, such as parallel-, fan-, and cone-beam; and the reconstruction procedure can also model the physics of the image detection process. An efficient method for evaluating the system projection matrix is presented. The system matrix is used in an iterative algorithm to reconstruct both the intensity and location of the distribution of points in the point cloud. Examples of the reconstruction of projection data generated by computer simulations and projection data experimentally acquired using a Jaszczak cardiac torso phantom are presented. This work creates a framework for voxel-less multiresolution representation of images in nuclear medicine.

Algorithms↗
PubMed2006

Patient-dentist-technician communication within the dental team: Using a colored treatment plan wax-up.

UNLABELLED: Communication among the restorative dental team must include the patient. The patient wants to know the details of the anticipated restorations; but because a patient is not aware of many dental innovations, care must be taken to provide them with a clear explanation of all anticipated treatment parameters. Many patients have little understanding of today's advancements in restorative procedures, and they may or may not understand all of the possibilities. Through effective communication, the patient gains confidence in the dental team and better understands the proposed restorative treatment. Patient satisfaction is significantly enhanced through effective communication. CLINICAL SIGNIFICANCE: This article describes the use of a diagnostic wax-up to facilitate optimal communication between the dental team and the patient.

Color↗