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PubMed2005

Ensuring global standards for medical graduates: a pilot study of international standard-setting.

Increasing physician and patient mobility has led to a move toward internationalization of standards for physician competence. The Institute for International Medical Education proposed a set of outcome-based standards for student performance, which were then measured using three assessment tools in eight leading schools in China: a 150-item multiple-choice examination, a 15-station OSCE and a 16-item faculty observation form. The purpose of this study was to empanel a group of experts to determine whether international student-level performance standards could be set. The IIME convened an international panel of experts in student education with specialty and geographic diversity. The group was split into two, with each sub-group establishing standards independently. After a discussion of the borderline student, the sub-groups established minimally acceptable cut-off scores for performance on the multiple-choice examination (Angoff and Hofstee methods), the OSCE station and global rating performance (modified Angoff method and holistic criterion reference), and faculty observation domains (holistic criterion reference). Panelists within each group set very similar standards for performance. In addition, the two independent parallel panels generated nearly identical performance standards. Cut-off scores changed little before and after being shown pilot data but standard deviations diminished. International experts agreed on a minimum set of competences for medical student performance. In addition, they were able to set consistent performance standards with multiple examination types. This provides an initial basis against which to compare physician performance internationally.

Clinical Competence↗

PubMed1993

Sequence-tagged microsatellite sites as markers in chicken reference and resource populations.

Two chicken genomic libraries were screened for the presence of poly(TG/AC) microsatellite tracts. The number of positive clones was low, confirming the low frequency of such microsatellites in the chicken genome relative to mammalian genomes. Polymorphism of 29 microsatellite tracts, comprising 11 from the library screening and 18 obtained from GenBank, was examined in the East Lansing and Compton reference families, in a resource population formed by a cross between a single White Rock broiler and inbred Leghorn females, and in a panel of birds from five layer stocks. Twenty microsatellites, primarily of the poly(TG/AC) type, were polymorphic in at least one of the populations. Thirteen of the microsatellites were polymorphic in the East Lansing reference family and 13 were also polymorphic in the resource population, confirming that the genetic distance between White Rock and White Leghorn is about as great as between Jungle fowl and White Leghorn. Only six microsatellites were polymorphic in the Compton reference family, formed by a cross between two White Leghorn strains. Twelve of the microsatellites were mapped in the East Lansing and/or Compton reference families. These were well dispersed among the various linkage groups and did not show any indications of terminal clustering.

Animals↗

PubMed1999

Clinical evaluation of an in-house reverse transcription-competitive PCR for quantitation of human immunodeficiency virus type 1 RNA in plasma.

An in-house reverse transcription (RT)-competitive PCR (RT-cPCR) for the quantitation of human immunodeficiency virus type 1 (HIV-1) RNA in plasma samples was developed and validated. The procedure involves (i) extraction of RNA with spin columns, (ii) ready-to-use bead-mediated RT, (iii) competitive PCR in a microtiter plate, (iv) agarose gel electrophoresis of the reaction products, and (v) densitometric analysis of the digitized image of the gel. Quadruplicate tests and dilution studies showed that the sensitivity and intertest coefficient of variability of the RT-cPCR are comparable to those of the reference AMPLICOR HIV-1 MONITOR test. The results obtained by the two assays with a panel of 45 clinical samples were in good agreement (mean difference, 0.36 +/- 0.25 log units). Analysis of 1,982 clinical samples by the in-house RT-cPCR yielded the typical range of plasma HIV-1 RNA levels with the expected inverse correlation between CD4 counts and HIV-1 RNA titers. In addition, testing of plasma from 36 subjects at weeks 0 and 4 with respect to the time of initiation of protease inhibitor therapy detected a significant decrease in HIV-1 viremia. The mean reduction in the HIV-1 RNA level was 0.914 log unit for those receiving saquinavir (P = 0.0210), 1.584 log units for those receiving indinavir (P = 0.0047), and 1.904 log units for those receiving ritonavir (P < 0.0001). The in-house RT-cPCR assay is simple to develop and perform and allows quantitation of HIV-1 RNA in 100 to 200 samples per operator per week. Since the cost is 1/8 to 1/10 of those of reference commercial assays, this procedure could be conveniently used in medium-scale laboratories.

Anti-HIV Agents↗

PubMed2000

Digital radiography versus conventional radiography in chest imaging: diagnostic performance of a large-area silicon flat-panel detector in a clinical CT-controlled study.

OBJECTIVE: The objective of this study was to compare the diagnostic performance of a digital large-area silicon flat-panel detector with that of a conventional screen-film system in clinical chest imaging using abnormal findings documented by CT as the reference standard. SUBJECTS AND METHODS: Eighty patients (46 men and 34 women; age range,18-91 years; mean age, 63 years) who underwent CT of the chest were examined with the new digital radiography system, which is based on a 43 x 43 cm silicon flat-panel detector, and with a conventional screen-film system, which is used routinely in clinical practice. Posteroanterior and lateral radiographs were obtained. Four radiologists analyzed the digital and conventional images separately for chest abnormalities and rated the images using a five-level scale of confidence; CT was used as the reference standard. Diagnostic value was assessed using receiver operating characteristic curves for each abnormality. RESULTS: No significant differences were found between the area under the receiver operating characteristic curve of the digital and that of the conventional radiography method for almost all investigated criteria. The only exception was mediastinal abnormalities, for which the digital method provided better results than the conventional method (p < 0.05). CONCLUSION: The diagnostic performance of the new large-area silicon flat-panel detector is equivalent or superior to that of the conventional screen-film system for clinical chest imaging and can replace conventional radiography systems. This new technology offers transmission and storage possibilities inherent to digital radiology that would facilitate daily practice and reduce the initial high costs in the long-term.

Adolescent↗

PubMed2000

B-lymphoblastoid cell lines as a source of reference DNA for human platelet and neutrophil antigen genotyping.

BACKGROUND: Human platelet and neutrophil antigens (HPAs, HNAs) are targets for platelet or granulocyte antibodies causing immune thrombocytopenia or neutropenia, respectively. Currently, genotyping is replacing phenotyping as the preferred method of diagnosis of immune cytopenia. To establish a reliable genotyping analysis, however, the availability as reference DNA of genomic DNA from persons of known genotype is essential. STUDY DESIGN AND METHODS: By the use of Epstein-Barr virus transformation, panels of B-lympho-blastoid cell lines (B-LCLs) from HPA- and HNA-phenotyped individuals were developed. Genomic DNA was isolated from these cell lines and tested as reference DNA for genotyping of persons for HPAs and HNAs. RESULTS: DNA derived from these B-LCLs was typed by polymerase chain reaction-restriction fragment length polymorphism and -sequence-specific primers. The results were in accordance with the genotyping from peripheral blood cells. These results were confirmed by 24 laboratories in Germany in a blind study. CONCLUSION: The inexhaustible source of reference DNA derived from B-LCLs allowed the evaluation of reliable HPA and HNA genotyping for quality control purposes. It should facilitate the development of DNA typing in blood centers and clinical laboratories.

Antigens↗

PubMed2003

Cartilage lesions in the ankle joint: comparison of MR arthrography and CT arthrography.

OBJECTIVE: To compare MR arthrography and CT arthrography for the evaluation of cartilage lesions in the ankle joint. DESIGN AND PATIENTS: Thirty-six consecutive patients with clinically suspected cartilage lesions were prospectively included in the study. A 1:1 mixture of diluted gadoteridol (4 mmol/l) and iopamidol (300 mg iodine/ml) was injected. The articular cartilages of the talus, tibia, and fibula were analyzed separately by two musculoskeletal radiologists. A review panel consisting of two musculoskeletal radiologists and an orthopedic surgeon represented the standard of reference. RESULTS: For reader 1 accuracy of MR arthrography in the talus/tibia/fibula (88%/88%/94%) was slightly inferior to CT arthrography (90%/94%/92%). For reader 2, the accuracy was 76%/78%/83% for MR arthrography, and 92%/93%/92% for CT arthrography, respectively. Interobserver agreement for MR arthrography was 79%/74%/89% (kappa 0.47/0.34/0.27), while interobserver agreement for CT arthrography was 89%/90%/89% (kappa 0.69/0.54/0.54). CONCLUSION: CT arthrography appears to be more reliable than MR arthrography for the detection of cartilage lesions in the ankle joint.

Adolescent↗

PubMed2002

Patterns of diagnostic error in trauma abdominal CT.

OBJECTIVE: To define patterns of diagnostic error in the interpretation of trauma abdominal CT. MATERIALS AND METHODS: Two hundred fifty-four out of 1751 abdominal CT scans performed for evaluation of trauma had a definite or equivocal diagnosis of an abdominal injury. Cases were re-read initially without reference to the original reports, in which 44 potential diagnostic errors were identified. A panel of two or three expert readers reviewed each of the 44 cases along with the original report to evaluate the diagnostic error and to search for patterns among the errors. RESULTS: Thirty-one of the 254 CT scans (12%) that were re-read contained non-trivial mistakes that could affect patient outcome. Seventeen were false negative and 14 were false positive. Diagnostic errors were found in the liver, spleen, kidney, retroperitoneum, and peritoneal cavity. Patterns of false-negative diagnosis included missed vascular contrast extravasation, missed hemoperitoneum, and missed right retroperitoneal hematoma. Patterns of false-positive diagnosis included: periportal edema or blood tracking, called a liver laceration; respiratory motion, called a splenic or renal injury; and linear or round lucencies in the spleen or liver, called a laceration. CONCLUSION: Diagnostic errors in interpreting trauma abdominal CT cluster in several recurring patterns. Awareness of these patterns may assist readers in avoiding future errors.

Journal Article↗

PubMed1987

Comparison of susceptibility results of anaerobic organisms determined by agar dilution method and Sceptor Anaerobe MIC/ID Micro Broth Dilution Panels.

A commercial broth microdilution system (Sceptor Anaerobe MIC/ID, BBL) for susceptibility testing of anaerobic bacteria was compared to a reference agar dilution system. Of the 172 organisms tested, only 7% failed to grow sufficiently for testing in the Sceptor system. In 1,590 antibiotic/organism combinations, 86.7% of the Sceptor results were identical or within one doubling dilution of the reference system. In 91.9% of the cases, interpretation of the results was same in both systems. Two hundred and twelve MIC values, however, differ by greater than or equal to 2 log2 dilution from the reference system. Due to this reduced correlation in the actual MIC values with the reference results, further studies are warranted before the Sceptor system can be recommended for routine use.

Agar↗

PubMedDate not supplied

Comparison of AMS-Vitek, MicroScan, and Autobac Series II for the identification of gram-negative bacilli.

Identification of Gram-negative bacilli by AMS-Vitek, MicroScan, and Autobac Series II was evaluated with 434 clinical isolates comprising glucose fermenters and glucose nonfermenters. The organisms were tested in each of the three systems (the AMS Vitek GNI card, the MicroScan Combo Plus Panel, and the Autobac 18 chamber cuvette). API 20E was used as the primary reference system. MicroScan and Vitek correctly identified 96.1% and 95.6% of the organisms, respectively. The Autobac Series II identified 82.3% of the organisms correctly. Results with MicroScan, Vitek, and Autobac were available in 24-48 hours, 4-18 hours, and 3-8 hours, respectively.

Bacterial Typing Techniques↗

PubMedDate not supplied

White cell related red cell antibodies.

Occasional sera react weakly with a few red cells in the antiglobulin phase but without a recognizable pattern. We sought to identify the nature of such antibodies in 27 samples referred to our HLA laboratory for lymphocytotoxin testing. All samples were tested against a panel of 15 red cells by a capillary tube antiglobulin technique developed to conserve sera. This technique correlates well with tube antiglobulin tests, and can be performed with either fresh or thawed red cells. Of 27 sera, 14 contained anti-HLA B7, B17, or A28, since they reacted only with red cells from donors whose lymphocytes were B7, B17, or A28. Eight further sera probably contained anti-B7, -B17, or -A28, but reacted with one or two additional red cells. Two samples agglutinated all panel red cells so the presence of anti-B7, B17, or A28 could not be determined. In three additional sera, lymphocytotoxin testing suggested that specificity other than anti-B7, B17, or A28 was present. Of 27 sera containing weak unidentified red cell antibodies, 22 (81%) contain definite or probable anti-B7, -B17, or -A28. The identity of these troublesome antibodies can be determined by maintaining red cell panels of donors whose HLA phenotypes are known.

Absorption↗

PubMed2003

Adjuvant systemic therapies in women with breast cancer: an audit of clinical practice in Italy.

BACKGROUND: Evidence-based guidelines, consensus conferences and experts' opinion are rarely promptly transferred to patient care. We audited prescriptions of adjuvant systemic therapies for Italian breast cancer patients and compared them with recommendations of an International Consensus Panel. PATIENTS AND METHODS: Disease characteristics and adjuvant therapies for 768 breast cancer patients referred to 87 Italian centers from 16 to 23 March 2000 were evaluated for adherence to the published recommendations. RESULTS: Endocrine therapy was not prescribed for 102 of 541 patients (19%) with endocrine-responsive disease and for 22 of 45 patients (49%) with unknown hormonal receptor status. Instead, endocrine therapy was prescribed for 22 of 182 patients (12%) with endocrine-unresponsive disease. Adjuvant chemotherapy was prescribed for 98% of the patients. The type of chemotherapy was the cyclophosphamide, methotrexate, 5-fluorouracil regimen for 453 of 754 (60%), while 253 of 754 (34%) received an anthracycline-based regimen. The proportion of patients with anthracyclines increased with the number of involved axillary nodes and grading, and decreased with age. Endocrine therapy was administered to 482 of 768 (63%) and was mainly represented by an antiestrogen. CONCLUSIONS: Lack of adherence to evidence-based guidelines for adjuvant treatment of Italian breast cancer patients was as high as 19%. It might be wise for national health authorities to promote education on life-saving procedures, like adjuvant systemic treatments, in cancer medicine.

Adult↗

PubMed1995

Routine application of polymerase chain reaction in the diagnosis of monoclonality of B-cell lymphoid proliferations.

We evaluated four polymerase chain reaction (PCR) methods for their efficiency in detecting monoclonality in a well-characterized panel of frozen and paraffin-embedded B-cell lymphoid proliferations. These approaches (referred to as FR3, FR3A, FR2, and FR1) are based on amplification of rearranged immunoglobulin heavy chain genes, using primers recognizing framework regions I, II, or III. FR3, FR3A and FR2 approaches reproducibly detected monoclonality in 51%, 72%, and 67% of DNAs from frozen lymphomas, respectively. No false-positives were observed. The combination of FR2 and FR3A methods raised the figure to 85%. Comparable results were obtained using paraffin-embedded lymphomas. Reproducibility of FR1 approach was unsatisfactory. The efficiency of all PCR approaches varied depending on lymphoma type. The highest detection rate was in small/intermediate cell and the lowest in centro-follicular lymphomas. Limiting dilution assays showed that PCR methods were able to detect monoclonal B-cell DNA representing 5% of nonlymphoid and 20% of polyclonal B-cell DNA. A diagnostic protocol may include quick and cost-effective PCR screening, particularly in cases of undetermined small cell lymphoid proliferations observed in fine needle aspirates or endoscopic biopsies. This would also reduce call-up of patients to obtain unfixed biopsies.

Base Sequence↗

PubMed1994

Genetic heterogeneity of Pseudomonas aeruginosa clinical isolates revealed by esterase electrophoretic polymorphism and restriction fragment length polymorphism of the ribosomal RNA gene region.

The intra-species differentiation of Pseudomonas aeruginosa was analysed by comparing the polymorphism of esterases by conventional polyacrylamide-agarose gel electrophoresis, the physicochemical properties of the variants of the major esterase P3 and the restriction fragment length polymorphism of ribosomal RNA gene regions (ribotyping) to O-serotyping for several panels of strains selected from among a series of 257 clinical isolates and two references strains, (ATCC nos. 10145 and 27853). The electrophoretic variation of four main kinds of esterase (P1-P4) and 11 additional esterases distinguished by their spectra of hydrolytic activity with synthetic substrates and by their sensitivity to di-isopropylfluorophosphate, allowed the discrimination of 67 zymotypes. Thirty-two esterase P3 variants were characterized by their pI, electrophoretic mobilities and titration curve analyses. They were distributed into two groups which, by these molecular criteria, seem to be distantly related. Combination of the patterns resulting from HindIII, EcoRI and BclI restriction endonuclease digestions allowed the discrimination of 33 ribotypes among 134 strains. The strains exhibiting esterase P3 variants of group 2 presented a distinct ribotype and belonged to serotype (O)12. They could constitute a distinct group within the species. For the majority of the strains, the absence of correlation between zymotype, ribotype and serotype argues for a high level of heterogeneity within P. aeruginosa and indicates that the parallel use of the first two methods represent a potential tool for epidemiological study.

DNA, Ribosomal↗

PubMed1995

Regional assignment of 68 new human gene transcripts on chromosome 11.

We have tested 80 expressed sequence-tagged site (eSTS) markers assigned to human chromosome 11 by the Genexpress program on a panel of somatic cell hybrids containing parts of this chromosome, characterized by cytogenetic data, reference markers, and with respect to the Généthon microsatellite genetic map. Sixty-eight new gene transcripts have been assigned to 25 subregions, one of which was newly defined by five of the eSTS markers. The markers are distributed on the short and long arms in agreement with their physical length. The genic map thus obtained has been integrated with the cytogenetic, genetic, and disease maps. Two eSTS markers have been further mapped with respect to a yeast artificial chromosome (YAC) contig close to the brain-derived neurotrophic factor (BDNF) gene and thus provide potential candidate genes for the mental retardation phenotype of WAGR (Wilms' tumor, aniridia, genitourinary abnormalities and mental retardation) syndrome. Altogether, the 68 new gene transcripts localized here represent more than a threefold increase in the number of unknown regionalized genes that could reveal potential candidate genes for the numerous orphan pathologies associated with chromosome 11.

Animals↗

PubMed1996

Development and mapping of polymorphic microsatellite markers derived from a chicken brain cDNA library.

Until now the genetic linkage map in chicken has ben based mainly on random genomic markers. The addition of expressed sequence tags (ESTs) to the genetic linkage maps is becoming more important because ESTs can form the basis for comparative mapping studies. This may be helpful for the detection of candidate genes for quantitative trait loci (QTLs). In our study we used a (TG)13 repeat as probe for the detection of microsatellites in a chicken brain cDNA library. After hybridization 0.15% of the cDNA clones gave a positive signal. The cDNA complexity of the library was high; of the 90 cDNA clones that were sequenced 60 occurred only once. For 29 clones primer sets for the polymerase chain reaction could be developed. Twenty-one microsatellites were polymorphic on one or more of the test panels and 15 markers could be mapped on either or both of the international reference families. Because sequence homology between chicken and mammalian cDNAs is sometimes low it was difficult to assess the level of sequence homology that indicated a true homologous transcript. In our study seven cDNA cones, of which three could be mapped, showed a relatively high percentage of sequence homology with sequences found in other species. Because sequencing and mapping of expressed sequence tags in human and mouse is progressing very rapidly, it is predicted that further information will soon be readily available. Therefore, increasing the number of expressed sequences on the chicken genetic linkage map will be of value for comparative mapping studies in the near future.

Animals↗

PubMed1997

Serological diagnosis of Chagas' disease: a potential confirmatory assay using preserved protein antigens of Trypanosoma cruzi.

The diagnosis of Chagas' disease relies mostly on data provided by immunologic tests, but inconclusive results often require elucidation, especially in blood banks. When six different types of Trypanosoma cruzi epimastigote antigens were studied by an immunoblotting assay (IBA), a preserved protein antigen (Ag PP) was found to present the most interesting immunochemical features because of its high reactivity with anti-T. cruzi antibodies. Thus, the IBA with Ag PP (PP IBA) was assessed with panels of coded and noncoded serum samples prepared in different laboratories, including the Brazilian Reference Laboratory for Chagas' Disease. It was found that serum samples from patients proved (clinically, eletrocardiographically, serologically, and epidemiologically) to have Chagas' disease consistently recognized 12 bands (140, 100, 85, 78, 59, 57, 46, 35, 27, 23, 20, and 18 kDa) of Ag PP. In contrast, sera from nonchagasic patients, including patients with mucocutaneous leishmaniasis, were negative or reacted weakly, and one serum sample did not have more than five different bands. These bands were 78, 57, 46, 35, 27, 23, 20, or 18 kDa. A criterion was adopted to interpret the results obtained in the PP IBA. The criterion considered positive a serum sample recognizing all 12 bands and considered negative a serum sample that did not recognize any of the bands except the eight nonspecific bands mentioned above. The PP IBA indicated maximum sensitivity and specificity as well as high positive and negative predictive values. The data demonstrate that the PP IBA discriminates chagasic from nonchagasic infections and seems to be applicable as a confirmatory assay for elucidating inconclusive results obtained by standard serology.

Animals↗

PubMed1999

A step approach to the clinical management of allergic rhinitis: prescription and over-the-counter therapeutic reference summary.

Allergic rhinitis is a debilitating condition. Successful clinical management requires patient education, allergen avoidance, and individualized pharmacotherapy. Immunotherapy may also be valuable for specific patients. With recent changes in the prescription of pharmacotherapies for allergic rhinitis symptoms, physicians or pharmacists may recommend over-the-counter (OTC) therapies. In an effort to develop a comprehensive therapeutic reference guide and a step approach to the clinical management of allergic rhinitis, a panel concluded the use of OTC agents, as either self-directed or parent-directed treatment, based on self-initiative or consultation with health care providers, may result in health care cost savings for both patient and health care provider, as well as reduced risks of overmedication and drug interaction with prescription medications for the patient.

Administration, Oral↗

PubMed2002

A testing algorithm for determination of HER2 status in patients with breast cancer.

The HER2 gene is amplified and overexpressed in 25-30% of breast carcinomas. Assessment of HER2 status for prognosis and treatment of breast cancer patients can be performed by immunohistochemistry and/or fluorescence in situ hybridization (FISH). To develop a testing algorithm for HER2 in breast cancers, we used FISH analysis to determine the HER2 gene copy number and immunostaining to detect the p185 protein. Interlaboratory, interobserver, and intermethod variabilities of immunohistochemistry were assessed. In 24 invasive breast carcinomas, the indices of HER2 status obtained by FISH and by a reference laboratory's DAKO HercepTest (immunostain) gave an overall concordance of 96%. The reference laboratory's stained slides were re-interpreted by an in-house panel of pathologists; the interpretation differed in one case. The panel's interpretations were concordant with the FISH results in all 24 cases. Interobserver variability for the panel's immunohistochemistry interpretations was assessed using three different immunostaining methods on 70 slides. The numerical (0-1+, 2+, 3+) scores showed greater variability among observers than did the overall positive/negative results. One pathologist reported inconsistent results in >30% of the slides evaluated. Borderline scoring of 1-2+ was reported in 18 slides (23%) by at least one observer. Incongruent interobserver immunohistochemistry scores, leading to different positive and negative interpretations, were obtained with 5 slides (7%). The majority of consensus positive cases exhibited strong membrane staining (3+). The majority of consensus negative cases scored as 0. Based on these observations, we developed a testing algorithm that maximizes the benefits of FISH and immunohistochemistry, providing physicians with accurate results for appropriate clinical care.

Algorithms↗