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PubMed1976

Noninvasive diagnosis of deep venous thrombosis.

Eighty-five patients suspected of having lower-extremity deep venous thrombosis (DVT) participated in a prospective study to test the diagnostic accuracy of four noninvasive techniques: Doppler ultrasonic flow study, electrical impedance plethysmography, the serial dilution protamine sulfate test, and an extensive physical examination. Ascending radiocontrast phlebography was the diagnostic standard of reference. We found that (1) when both Doppler and impedance examinations were positive, the diagnosis of DVT could be considered virtually certain; (2) impedance and Doppler examinations, when used in combination, were reliable screening tests capable of establishing or excluding the presence of thigh DVT; (3) physical examination and the serial dilution protamine sulfate test were unreliable screening techniques for DVT; (4) techniques other than the noninvasive methods investigated were needed to reliably detect or to exclude popliteal and call DVT.

Diagnostic Errors↗

PubMed1993

Primary and preventive care services provided by obstetrician-gynecologists.

OBJECTIVE: To determine the level and types of primary and preventive care services delivered by obstetrician-gynecologists. METHODS: A self-administered questionnaire was mailed to a random sample of 1250 obstetrician-gynecologists practicing in the United States. The response rate was 71%. RESULTS: Fifty-three percent of the respondents indicated that they provide primary and preventive care during more than half of their practice time. Although obstetrician-gynecologists provide a wide range of preventive services, the proportion of doctors providing any specific service varies. Whereas virtually all (92% or more) obstetrician-gynecologists provide or order blood pressure screening, breast examinations, mammography, and Papanicolaou tests, only six of ten report regular cholesterol screening for most of their patients. A higher percentage of female obstetrician-gynecologists, who are on average younger than their male counterparts, report that they provide primary preventive services to most of their patients. CONCLUSION: The majority of obstetrician-gynecologists provide a wide range of primary and preventive care services to their patients, although there is variability in the proportion of doctors providing any specific service to most (60% or more) of their patients.

Adult↗

PubMed2002

Secondary prevention: screening and surveillance of persons at average and high risk for colorectal cancer.

Secondary prevention of colorectal cancer with FOBT and endoscopy with polypectomy decreases cancer deaths. Other available modalities include genetic tests and imaging studies, but outcomes data are not yet available. Issues remain concerning the most appropriate test, the optimal intervals, and cost-efficacy. Patients may be stratified by personal and family risk, and specific strategies may be used. Newer developments in genetic tests and imaging, including virtual colonoscopy, hold promise for the future. The most important issue at present is to have people screened or surveilled by any of the recommended modalities.

Adenoma↗

PubMed1999

Virtual endoscopy in abdominal MR imaging.

As illustrated in this review, the diagnostic utility of VIE is highly dependent on the individual application. Virtual intraluminal endoscopy does not alter the informational content of the data set; rather, the data is presented in a different manner. In view of the considerable time requirements still associated with the VIE rendering process, the additional diagnostic value gained by VIE must be determined for each of the potential applications. Thus VIE was shown to be of no additional value in the assessment of 3D MR angiographic data sets of the abdominal aorta and renal arteries. For MR colonography, on the other hand, in vitro experiments as well as in vivo experience have demonstrated a vast diagnostic value as a primary screen supplemented by detailed analysis of reformatted images in all three orthogonal axes. In summary, virtual intraluminal imaging is a powerful tool for exploring 3D MR data sets of various abdominal structures from a different perspective. Clearly much more work is required to determine its diagnostic utility relative to its cost.

Abdomen↗

PubMed2002

High-throughput and in silico techniques in drug metabolism and pharmacokinetics.

The high-throughput screening (HTS) of large proprietary compound collections and combinatorial libraries has increased the pressure on gathering pharmacokinetic and drug metabolism data as early as possible. Properties related to absorption, distribution, metabolism and excretion (ADME) can be estimated by a range of in vivo and in vitro methods, most of which are now available or under development in high(er)-throughput modus. In addition, progress has been made in in silico methods using various quantitaTive structure-activity relationship (QSAR) and molecular modeling techniques that employ a range of recently introduced descriptors tailored to e-ADME. These in silico approaches are promising filters for virtual libraries to aid synthesis as well as the selection of compounds for acquisition and screening in the early stages of drug discovery.

Absorption↗

PubMed2000

Improving synthetic lethal screens by regulating the yeast centromere sequence.

The synthetic lethal screen is a useful method in identifying novel genes functioning in an alternative pathway to the gene of interest. The current synthetic lethal screen protocol in yeast is based on a colony-sectoring assay that allows direct visualization of mutant colonies among a large population by their inability to afford plasmid loss. This method demands an appropriate level of stability of the plasmid carrying the gene of interest. YRp-based plasmids are extremely unstable and complete plasmid loss occurs within a few generations. Consequently, YCp plasmids are the vector of choice for synthetic lethal screens. However, we found that the high-level stability of YCp plasmids resulted in a large number of false positives that must be further characterized. In this study, we attempt to improve the existing synthetic lethal screen protocol by regulating the plasmid stability and copy number. It was found that by placing a yeast centromere sequence under the control of either inducible or constitutive promoters, plasmid stability can be significantly decreased. Hence, altering the conditions under which yeast cells carrying the plasmid PGAL1-CEN4 were cultivated allowed us to develop a method that eliminated virtually 100% of false positives and drastically reduced the time required to carry out a synthetic lethal screen.

Aminohydrolases↗

PubMed2005

Spatial decisions in rats based on the geometry of computer-generated patterns.

Animals often demonstrate the ability to use the geometric configuration of multiple landmarks for orientation in the environment. We developed a new behavioral task using a computer screen for presentation of visual stimuli allowing the rats to make navigational decisions in real space according to the geometric configuration of external virtual patterns (designed as a possible representation of this space). The rats were placed in a Skinner box with four nosing holes in the transparent front wall through which the computer screen was visible. They were trained in successive phases: first the visual stimulus displayed on the screen directly marked the rewarded nosing hole, then the displayed stimuli were reduced in size or displaced, thus disconnected from the response space. The results suggested that rats were able to use the geometric configuration of stimuli presented on the computer screen for navigational decisions in real space.

Animals↗

PubMed2006

[Breast Center--a virtual unit for the multidisciplinary care of breast patients].

Breast cancer, the most prevalent female malignancy represents a major health problem. Breast cancer mortality may be halved by high quality mammography screening and care. The most efficient screening and the best treatment of patients are available at the breast centers that are equipped with special facilities, expertise and significant experience via the treatment of a high number of patients. Breast center is a virtual unit based on the collaboration of various professionals; a tight institutional frame is not a must. In these comprehensive centers, 150 breast cancer patients per year at a minimum are treated, and the most efficient special treatment methods are available. The core members of the staff are the breast pathologists, the mammographists, the breast surgeons, the oncologists/oncoradiologists, the breast nurses, the technicians and the data managers. An easy access to the service of the non-core members, the plastic surgeons, the psychologists, the psychiatrists and the clinical geneticists is necessary. An optimal collaboration of the various experts may be achieved by a training of the members, regular multidisciplinary meetings and guidelines developed and accepted by all. The requirements of a breast center have been published by the European Society of Mastology (EUSOMA), and a directory of the accredited European breast centers is maintained. The Breast Unit of the University of Szeged has been found eligible by EUSOMA to be included in the directory of the European breast units. Two mammographists do screening-mammography and clinical examination, 2 pathologists perform cytopathological, histopathological and immunohistochemical examinations. Three surgeons operate on more than 250 breast cancer patients per year, and apply wire or isotope (ROLL) localisation in case of non-palpable lesion. A plastic surgeon is available if necessary. In a half of all cases, sentinel mapping is performed with isotope- and blue dye-labelling. Two radiotherapists apply conformal radiotherapy in 250 cases per year, and 2 oncologists perform modern chemotherapies in 200 cases as a yearly average; 50 new advanced/metastatic cases per year require oncological treatments. Breast nurses, a psycho-oncologist and a mental hygienist nurse assist the team. There is access to lymphedema treatment and physiotherapy. The final goal of the program is to provide all women with high quality mammography screening and care, if necessary.

Breast Diseases↗

PubMed2003

Colon polyps and cancer.

A large number of studies published last year in peer-reviewed medical journals help to better define the advantages and limitations of the different options for colorectal cancer screening. Direct colonoscopy screening appears to have the greatest potential to markedly reduce both the incidence and mortality of colorectal cancer, but many obstacles limiting its widespread use in the general at-risk population still exist, and many questions remain incompletely answered. Recent studies stress the fact that finding and resecting advanced adenomatous polyps, and thereby preventing cancer, is becoming a primary objective of screening programs. Several papers also show the potential of emerging new methods of screening for specific markers in stool and for imaging the colon with computed-tomographic colonography (virtual colonoscopy). Other important publications highlighted in this review deal with the diagnosis of colorectal neoplasia, familial colorectal cancer, colorectal polyps and the adenoma-carcinoma sequence, and new and novel methods of improving the efficiency and safety of colonoscopic polypectomy.

Adenomatous Polyps↗

PubMed2000

[Virtual reality in MR colonography].

Early detection and subsequent removal of colorectal polyps have been shown to constitute an effective approach for decreasing the incidence of colorectal cancer. The lack of an ideal modality for colorectal polyp screening stimulated interest in the development of CT-colonography and MR-colonography. Both techniques allow the colon to be analyzed in a cross-sectional as well as a virtual endoscopic format. Causing no side-effects and not concerning for radiation exposure MR-colonography warrants further consideration. Additional to detecting polyps down to 6 mm in size the inner wall contour and the morphology of the colonic wall itself can be assessed. New developments like fecal tagging will increase patients acceptance comparing to other diagnostic techniques. In search of an ideal modality for polyp screening MR-colonography will become a potent option in the diagnostic arsenal.

Colonic Polyps↗

PubMedDate not supplied

Diagnostic efficacy and validity of the ThinPrep method in cervical cytology.

OBJECTIVE: To examine the efficacy of the ThinPrep method, an automated, fluid-based technique for the collection and preparation of exfoliated and aspirated cells in cervical cytology. STUDY DESIGN: A total of 251 patients participated. From each patient a sample was obtained by scraping with a wooden spatula, split and prepared with both conventional Papanicolaou and ThinPrep methods. In the ThinPrep processor, epithelial cells were homogenized in a vial of preservative solution and randomly sampled onto a microscopic slide. From a single vial of sample suspension a series of 10 ThinPrep slides of the same quality were made. All cells were concentrated within an approximately 20-mm-diameter circle in a uniform, thin layer on the ThinPrep slide. RESULTS: Twenty-five percent of the screening area, 10% of the epithelial cells observed and 50% of the screening time were required to arrive at a final diagnosis as compared with the Papanicolaou smear. Virtually complete concurrence was ascertained between the Papanicolaou and ThinPrep diagnoses, for direct agreement of 95.3% and agreement within one diagnostic grade of 99.5%. CONCLUSION: An overall improvement was ascertained in the preparation of microscopic slides and the recognition of abnormal cells with the ThinPrep method.

Female↗

PubMed1991

Urine screening practices in methadone maintenance clinics. A survey of how the results are used.

The urinalysis practices of 324 methadone maintenance clinics were surveyed using a brief self-report questionnaire. Results indicate that there is wide variability in collection practices and clinic responses to positive findings. Virtually all clinics provide counseling and revocation of take-home methadone doses as a response to positive urinalysis results. However, increase in urine screening frequency, methadone dose adjustments, contingency contracting, group therapy, and eventual discharge are interventions also used. The implementation of different interventions varied as a function of clinic size, city size, region of the country, and program funding source.

Community Mental Health Centers↗

PubMed2003

An improved HPLC measurement for GSH and GSSG in human blood.

The pathophysiological sequelae of oxidative/nitrosative stress are notoriously difficult to quantify. Despite these impediments, the medical significance of oxidative/nitrosative stress has become increasingly recognized to the point that it is now considered to be a component of virtually every disease. The level of oxidative stress can be quantified in blood by the measurement of the increase in glutathione disulfide (GSSG) and the decrease in the GSH/GSSG ratio, which has been shown to be altered in a variety of human diseases such as lung inflammation, amyotrophic lateral sclerosis, chronic renal failure, malignant disorders, and diabetes. Among the proposed methods for GSH/GSSG detection, the amino group derivatization with 2,4-dinitrofluorobenzene followed by HPLC separation has the advantage of allowing evaluation of both parameters within a single run contemporaneously. However, it has been shown that the application of this method on blood samples is not reproducible. In this report, we offer an explanation for these experimental limits and suggest some modifications that allow the application of this method to blood samples. The modified method has a low detection limit (0.5 microM, i.e., 1.4 pmoles) and a high reproducibility with a within-run imprecision of less than 2%. It could have a wide application as it is simple, virtually artifact-free, and not time-consuming, especially for large-scale screening studies.

Chromatography, High Pressure Liquid↗

PubMed1998

Distribution of transferrin saturation in an Australian population: relevance to the early diagnosis of hemochromatosis.

BACKGROUND & AIMS: An elevated transferrin saturation is the earliest phenotypic abnormality in hereditary hemochromatosis. Determination of transferrin saturation remains the most useful noninvasive screening test for affected individuals, but there is debate as to the appropriate screening level. The aims of this study were to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals and to evaluate potential transferrin saturation screening levels. METHODS: Statistical mixture modeling was applied to data from a survey of asymptomatic Australians to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals. To evaluate potential transferrin saturation screening levels, modeling results were compared with data from identified hemochromatosis heterozygotes and homozygotes. RESULTS: After removal of hemochromatosis homozygotes, two populations of transferrin saturation were identified in asymptomatic Australians (P < 0.01). In men, 88.2% of the truncated sample had a lower mean transferrin saturation of 24.1%, whereas 11.8% had an increased mean transferrin saturation of 37.3%. Similar results were found in women. A transferrin saturation threshold of 45% identified 98% of homozygotes without misidentifying any normal individuals. CONCLUSIONS: The results confirm that hemochromatosis heterozygotes form a distinct transferrin saturation subpopulation and support the use of transferrin saturation as an inexpensive screening test for hemochromatosis. In practice, a fasting transferrin saturation of > or = 45% identifies virtually all affected homozygous subjects without necessitating further investigation of unaffected normal individuals.

Adult↗

PubMed2004

An analysis of the potential impact of computed tomographic colonography (virtual colonoscopy) on colonoscopy demand.

BACKGROUND AND AIMS: There has been much speculation about the potential impact on the use of conventional colonoscopy if "virtual" computed tomographic colonography (CTC) became a widely accepted modality for colorectal cancer (CRC) screening. However, no formal analysis of the impact of CTC on colonoscopy demand has been reported. METHODS: A mathematical model to predict colonoscopy demand based on several relevant input parameters was constructed. Current national colonoscopy practice, estimated using various published reports, was used as the foundation to project colonoscopy demand if CTC were implemented as the primary CRC screening modality. RESULTS: In the base-case analysis, if CTC were used as the primary modality for CRC screening, 1.78 million colonoscopies could be eliminated from the total 6.47 million in 2003. Depending on the polyp size threshold used to define a CTC study as positive (6 or 10 mm), this loss would be partially offset by 1.21 million (6 mm) or .34 million (10 mm) follow-up colonoscopies for CTC examinations with positive findings, resulting in a net loss of .57 million (8.8% decrease) (6 mm) or 1.44 million (22.3% decrease) (10 mm). Extensive sensitivity analyses showed that the findings of this model were robust and insensitive to most parameters tested but were sensitive to a few parameters, including the percentage of CTC examinations with positive findings. CONCLUSIONS: Wide-scale implementation of CTC for CRC screening would likely lead to a decrease in use of conventional colonoscopy. The percentage of CTC studies with positive findings seemed to be a pivotal variable, which would be determined in large part by the polyp size ultimately established to define a positive finding.

Colonography, Computed Tomographic↗

PubMed2003

Comprehensive transposon mutant library of Pseudomonas aeruginosa.

We have developed technologies for creating saturating libraries of sequence-defined transposon insertion mutants in which each strain is maintained. Phenotypic analysis of such libraries should provide a virtually complete identification of nonessential genes required for any process for which a suitable screen can be devised. The approach was applied to Pseudomonas aeruginosa, an opportunistic pathogen with a 6.3-Mbp genome. The library that was generated consists of 30,100 sequence-defined mutants, corresponding to an average of five insertions per gene. About 12% of the predicted genes of this organism lacked insertions; many of these genes are likely to be essential for growth on rich media. Based on statistical analyses and bioinformatic comparison to known essential genes in E. coli, we estimate that the actual number of essential genes is 300-400. Screening the collection for strains defective in two defined multigenic processes (twitching motility and prototrophic growth) identified mutants corresponding to nearly all genes expected from earlier studies. Thus, phenotypic analysis of the collection may produce essentially complete lists of genes required for diverse biological activities. The transposons used to generate the mutant collection have added features that should facilitate downstream studies of gene expression, protein localization, epistasis, and chromosome engineering.

Escherichia coli↗

PubMed1994

Reversible renal failure caused by a microsporidian infection.

OBJECTIVE: To report a case of renal failure associated with microsporidian infection in an HIV-seropositive patient. DESIGN: Case report. SETTING: Chelsea and Westminster Hospital, London, England, UK. PATIENT: An HIV-seropositive patient presented febrile with abdominal pain who developed renal failure. Renal biopsy and urinalysis showed infection with a microsporidian of the genus Encephalitozoon. INTERVENTION: Treatment with albendazole (400 mg) twice daily was associated with disappearance of infection from the urine, clinical improvement and return of renal function virtually to normal. CONCLUSION: HIV-seropositive individuals with renal failure should have urine screened for microsporidia. The administration of albendazole in such cases may reverse renal failure.

AIDS-Related Opportunistic Infections↗

PubMed2004

The PRESAT-vector: asymmetric T-vector for high-throughput screening of soluble protein domains for structural proteomics.

A rapid unidirectional method for cloning PCR-amplified cDNA fragments into virtually any fusion protein expression vector is described. The method, termed PRESAT-vector cloning, is based on a T-vector technique that does not require restriction endonuclease digestion of the PCR product. Subsequently, we applied a novel ORF selection method of the ligated plasmid products. This second step involves restriction endonuclease treatment that eliminates the plasmids containing an ORF in the wrong orientation prior to transformation into the bacterial host for further protein expression studies. To achieve this selection, we customized the 5'-sequence of the "rear" PCR primer corresponding to the C terminus of the protein to be expressed. The colonies harbored only the ligated products of the desired orientation at >90% efficiency. This method is applied to a GST fusion expression system, and an HTS system for soluble proteins from an expression library was tested.

ATPases Associated with Diverse Cellular Activitie↗