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PubMedDate not supplied

[Use of recombinant HBcore antigen for development of the diagnostic test-system].

The plasmid construction expressing recombinant HBc antigen (HbcAg) in Escherichia coli cells under the control of the PL promoter of phage I, was obtained. The specific activity of the antigen thus obtained was controlled by the enzyme immunoassay (EIA) method and compared with the reference system "AxSYM CORE assay" ("Abbott", USA) with four panels of sera (altogether 111 samples). The coincidence of the results of the compared test system with the reference was 96.4%, which made it possible to recommend this genetic construction of recombinant HBcAg for the production of EIA systems.

Bacteriophage lambda↗
PubMed1991

[Involvement of the olfactory system in learning and memory: a close correlation between the olfactory deficit and the course of Alzheimer's disease?].

Alzheimer's disease is characterized pathologically by the development of numerous neuritic plaques (NP) and neurofibrillary tangles (NFT) within the brain. Recent studies of Alzheimer's disease patients have uniformly shown marked impairment on odor recognition. In Alzheimer's disease, brain structures closely related to the olfactory bulb (OB) or the olfactory system demonstrate significantly histopathological changes. Anatomically, the olfactory bulbs project through the lateral olfactory tracts to the olfactory tubercules, the pyriform cortex, the cortical amygdala nucleus, and the ventrolateral entorhinal area. In addition, the olfactory system is particularly rich in acetylcholine and other neurotransmitters, many of which are deficient in Alzheimer's disease. Furthermore, increased numbers of NP and NFT in the OB and anterior olfactory nucleus have been demonstrated in patients with Alzheimer's disease. These findings suggest that there is a close correlation between the impairment of olfactory processes and the course of Alzheimer's disease. In animal study, many investigators have become interested in the role that olfactory cues play in learning/memory. Bilateral olfactory bulbectomy in rats impairs passive avoidance and radial-maze task in acquisition. In both working and reference memory tasks using a 3-panel runway apparatus, OB-lesioned rats showed a marked increase of errors (pushes made on the two incorrect panels of the 3-panel gates located at 4 choice points). Furthermore, in 3-lever operant task using a delayed matching-to-lever location procedure, OB lesions decreased significantly the correct response in test trials without affecting that in training trials. These findings indicate that olfactory bulbectomy leads to severe impairment of memory in rats. Interestingly, the appearance of memory impairment is delayed following OB lesions. Earlier studies also had shown that the rats do not require olfactory cues for efficient performance in some learning task. Judging from these findings, the impairment of memory do not attribute solely to olfactory deficit. Therefore, it seems likely that the impairment of memory following the bulbectomy might be due to secondary degeneration in several areas projected from the OB rather than to the olfactory deficit. Unfortunately, investigation of the mechanism underlying the development of Alzheimer's disease has been hampered by the lack of an animal model. In this context, as reviewed here, since OB-lesioned rats show severe impairment of memory with some emotional changes, the olfactory bulbectomy syndrome may be a useful model of Alzheimer's disease. Such a review inevitably raises more questions than its answers, but it is hoped that it may stimulate further investigation in this new field.

Alzheimer Disease↗
PubMed1997

Quality assurance programme for drug susceptibility testing of Mycobacterium tuberculosis in the WHO/IUATLD Supranational Laboratory Network: first round of proficiency testing.

SETTING: Quality assurance of the WHO/IUATLD global tuberculosis drug resistance surveillance programme. OBJECTIVE: To perform a proficiency test of drug susceptibility procedures within the WHO/IUATLD network of supranational reference laboratories (SRL). DESIGN: Identical culture panels consisting of 20 clinical isolates of Mycobacterium tuberculosis containing both drug susceptible and drug resistant cultures were tested by the 16 laboratories of the network for resistance to streptomycin, isoniazid, rifampicin and ethambutol. The drug susceptibility testing procedures included the proportion, absolute concentration and resistance ratio methods as well as their variants, including the radiometric BACTEC 460 method. RESULTS: The first round of proficiency testing has shown that the specificity of drug susceptibility testing within the SRL network was significantly higher than its sensitivity. The testing of isoniazid and rifampicin shows a high degree of agreement between the labs, but discordant results can be obtained with streptomycin and ethambutol. CONCLUSION: Drug susceptibility procedures for the testing of isoniazid and rifampicin, the two anti tuberculosis drugs which define multidrug-resistant tuberculosis, are highly reliable within the SRL network. Procedures for drug susceptibility testing of streptomycin and ethambutol are still in need of standardization.

Antitubercular Agents↗
PubMed1997

[Evaluation of a western blot system (DAVIH-BLOT) for the confirmation of HIV-1 antibodies].

It is reported the evaluation of the DAVIH-BLOT system (DAVIH Laboratories, Cuba) against the proficiency panels sent to the National AIDS Reference Laboratory by the World Health Organization (WHO) in order to ensure the quality in the diagnosis of HIV antibodies during 1989, 1991 and 1993. The system is also compared with those of the Dupont and Diagnostic Pasteur firms in a group of 467 positive sera by ELISA. On studying the WHO's samples, the system proved to be highly sensitive and specific. In the comparison made with the HIV-1 Western Blot IgG version 1.2 (Dupont company, USA) and with the LAV-blot 1 (Diagnostic Pasteur, France), there was a coincidence of 100 and 97%, respectively.

AIDS Serodiagnosis↗
PubMed2002

Validation of an indirect enzyme-linked immunosorbent assay for the detection of antibody against Brucella abortus in cattle sera using an automated ELISA workstation.

An automated indirect enzyme-linked immunosorbent assay (I-ELISA) for the serological diagnosis of bovine brucellosis was developed and validated in-house. A total of 4,803 cattle sera from South Africa (n = 3,643), Canada (n = 652), Germany (n = 240), France (n = 73) and the USA (n = 195) was used. The South African panel of sera represented 834 sera known to be positive by the Rose Bengal test (RBT), serum agglutination test (SAT) and complement fixation test (CFT), 2709 sera that were negative by CFT, and 100 sera from animals vaccinated with a standard dose of Brucella abortus strain 19. Overseas sera were obtained from reference non-vaccinated brucella-free cattle (n = 834), naturally infected (n = 72), experimentally infected (n = 71), and vaccinated animals (n = 83). Also 100 sera collected from cattle in Canada and known to be positive by competitive ELISA (C-ELISA) were used. The intermediate ranges ("borderline" range for the interpretation of test results) were derived from two-graph receiver operating characteristics analysis. The lowest values of the misclassification cost-term analysis obtained from testing overseas panels, covered lower I-ELISA cut-off PP values (0.02-3.0) than those from local panels (1.5-5.0). The relatively low cut-off PP values selected for I-ELISA were due to the fact that the positive control used represents a very strong standard compared to other reference positive sera. The greater overlap found between negative and positive cattle sera from South Africa than that between reference overseas panels was probably due to the different criteria used in classifying these panels as negative (sera from true non-diseased/non-infected animals) or positive (sera from true diseased/infected animals). The diagnostic sensitivity of the I-ELISA (at the optimum cut-off value) was 100% and of the CFT 83.3%. The diagnostic specificity of I-ELISA was 99.8% and of the CFT 100%. Estimate of Youden's index was higher for the I-ELISA (0.998) than that for the CFT (0.833). Analysis of distribution of PP values in sera from vaccinated and naturally infected cattle shows that in vaccinated animals all readings were below 31 PP where in infected ones these values represented 43%. Therefore, it appears that I-ELISA could be of use in identifying some naturally infected animals (with values > 31 PP), but more sera from reference vaccinated and infected animals need to be tested to further substantiate this statistically. Of 834 sera positive by RBT, SAT and CFT, 825 (98.9%) were positive in the I-ELISA. Compared to C-ELISA the relative diagnostic sensitivity of the I-ELISA was 94% and of the CFT 88% when testing 100 Canadian cattle sera. Of 258 South African cattle sera, of which 183 (70.9 %) were positive by the I-ELISA and 148 (57.4 %) by the CFT, 197 (76.4%) were positive by C-ELISA when re-tested in Canada. One has to stress, however, that Canadian C-ELISA has not been optimised locally. Thus, the C-ELISA was probably not used at the best diagnostic threshold for testing South African cattle sera. This study shows that the I-ELISA performed on an automated ELISA workstation provides a rapid, simple, highly sensitive and specific diagnostic system for large-scale detection of antibodies against B. abortus. Based on the diagnostic accuracy of this assay reported here, the authors suggest that it could replace not only the currently used confirmatory CFT test, but also the two in-use screening tests, namely the RBT and SAT.

Agglutination Tests↗
PubMed2005

Evaluation of a rapid direct assay for identification of bacteria and the mec A and van genes from positive-testing blood cultures.

We performed the first evaluation of a DNA strip assay (GenoType blood culture; Hain Lifescience, Nehren, Germany) for the detection of the most relevant bacterial sepsis pathogens directly from positive BACTEC blood culture bottles (Becton Dickinson, Heidelberg, Germany). The test comprises two panels, one for the direct species identification of important gram-positive cocci and the other for gram-negative rods. Additionally, detection of the mec A and the van genes are implemented. The GenoType assay was validated regarding its analytical sensitivity with blood cultures spiked with reference strains. Approximately 10(4) CFU per ml were detected. Analytical specificity was calculated with a test panel of 212 reference strains. Of the strains tested, 99% were correctly identified. Additionally, 279 consecutive blood cultures signaled positive by BACTEC were processed directly, in comparison to conventional methods. The GenoType assays were performed according to Gram stain morphology. A total of 243 (87.1%) of the 279 organisms isolated were covered by specific probes. A total of 152 organisms were gram-positive cocci, of which 148 (97.4%) were correctly identified by the GenoType assay. Ninety-one organisms were gram-negative rods, of which 89 (97.8%) were correctly identified. Concerning mec A gene detection, GenoType assay correctly detected 12 of 13 methicillin-resistant Staphylococcus aureus isolates. One Enterococcus faecium isolate with a positive van A gene isolated was correctly differentiated by the assay. All results were available 4 h after the results of microscopic analysis. The evaluated GenoType blood culture assay showed fast and reliable results in detecting the most important sepsis pathogens and the mec A and van genes directly from positive blood culture bottles.

Bacterial Proteins↗
PubMed2000

HIV-1 subtype H near-full length genome reference strains and analysis of subtype-H-containing inter-subtype recombinants.

OBJECTIVE: To characterize near-full-length genomes of two HIV-1 subtype H strains. To extend sequence data to include full env and gag, and analyse and redefine, previously documented subtype H strains. DESIGN: Near-full-length genomes of HIV-1 env subtype H strains VI991 and VI997 were amplified, cloned, sequenced, phylogenetically analysed and compared with a panel of 23 HIV-1 group M reference isolates. The mosaic nature of previously published subtype H strains VI557 and CA13 was reanalysed. MATERIALS AND METHODS: Peripheral blood mononuclear cells (PBMC) from individuals harbouring strains VI991 and VI997 were co-cultivated with PHA stimulated donor PBMC. Near-full-length genomes of VI991 and VI997, and gag and env genes of CA13 and VI557, were amplified by polymerase chain reaction, cloned and sequenced. Intersubtype recombination analyses were performed by similarity plot, bootscanning and phylogenetic analysis. RESULTS: Near-full-length clones of HIV-1 VI991 and VI997 are representative of subtype H. They form a phylogenetic cluster with the only previously described subtype H representative HIV-1 90CF056.1, regardless of the genome region analysed. VI557 is redefined as a gag and env subtype H mosaic virus containing unclassified fragments. CA13 is a complex intersubtype recombinant between subtypes A, H and unclassified strains CONCLUSION: Near-full-length genome analysis identified HIV-1 VI991 and VI997 as two new subtype H representatives. These reagents will allow defining and classifying non-recombinant as well as recombinant HIV-1, eventually helping to solve the puzzle of HIV-1 subtypes.

Base Sequence↗
PubMed2002

Biomedical applications and studies of molecular evolution: a proposal for a primate genomic library resource.

The anticipated completion of two of the most biomedically relevant genomes, mouse and human, within the next three years provides an unparalleled opportunity for the large-scale exploration of genome evolution. Targeted sequencing of genomic regions in a panel of primate species and comparison to reference genomes will provide critical insight into the nature of single-base pair variation, mechanisms of chromosomal rearrangement, patterns of selection, and species adaptation. Although not recognized as model "genetic organisms" because of their longevity and low fecundity, 30 of the approximately 300 primate species are targets of biomedical research. The existence of a human reference sequence and genomic primate BAC libraries greatly facilitates the recovery of genes/genomic regions of high biological interest because of an estimated maximum neutral nucleotide sequence divergence of 25%. Primate species, therefore, may be regarded as the ideal model "genomic organisms". Based on existing BAC library resources, we propose the construction of a panel of primate BAC libraries from phylogenetic anchor species for the purpose of comparative medicine as well as studies of genome evolution.

Animals↗
PubMed1998

Primary tumors of the elbow: a review of the Leeds Regional Bone Tumour Registry.

A review of the Leeds Regional Bone Tumour Registry found that primary tumors of the elbow constituted 25 (1.2%) of the 2154 cases recorded between 1958 and 1992. Fifty percent occurred in the ulna, 20% in the radius, 20% in the humerus, and 10% in the soft tissues. Benign tumors were more common than malignant ones (19 versus 6). Malignant tumors occurred more frequently in older patients (mean age: 45 years) compared with patients with benign tumors (mean age: 17 years). The correct preoperative diagnosis was made on clinical or radiologic findings in only 16 patients, and the histologic diagnosis of the referring pathologist was changed by the Bone Tumour Registry panel in one case. In view of the difficulty of accurately diagnosing primary bone tumors, all such lesions should be referred to a regional bone tumor registry. Such registries can provide valuable information about these uncommon conditions for research, teaching, and education.

Adolescent↗
PubMed1990

Evaluation of three panels of monoclonal antibodies for the identification of human rotavirus VP7 serotype by ELISA.

Three panels of monoclonal antibodies used for rotavirus serotype identification by enzyme-linked immunosorbent assay (ELISA) were evaluated at the National Institutes of Health, USA, to identify antibodies suitable for distribution to laboratories involved in WHO-sponsored trials of rotavirus vaccines. Two of the panels were comparably effective in identifying the serotype of each of the human rotavirus reference strains of serotype 1, 2, or 3. In addition, one of the panels included a monoclonal antibody that was effective in identifying strains of serotype 4. However, two different lots of a third, commercially available panel were not effective in identifying the eight strains representing the four serotypes. A third shipment of this panel was therefore tested using revised instructions and, under these conditions, it was effective in serotyping seven of the eight reference strains. It appears that a battery of monoclonal antibodies for each serotype may be required to identify antigenic variants within a serotype. Additional studies are needed to assess the extent of antigenic variation in rotavirus field strains.

Antibodies, Monoclonal↗
PubMed2003

Simplified panel of assimilation tests for identification of Acinetobacter species.

A total of 66 Acinetobacter isolates obtained from JIPMER hospital wards were subjected to phenotypic identification schemes involving 25-test and a simplified 13-test panel of carbon utilization or assimilation tests. Reference strains belonging to different DNA groups (n=24) were also tested. Identification was done using numerical approach based on a matrix constructed of phenotypic data published elsewhere and the strains were assigned to different DNA groups according to classification of Tjernberg & Ursing. Sixty-six strains tested represented 10 DNA groups in matrix of large test panel; at a probability level of 0.95. Much simplified scheme of 13 assimilation test panel failed to differentiate some isolates with in A. calcoaceticus-A. baumannii complex (Acb-complex) unlike extended panel. In all, from the large panel 95% of isolates were identified correctly among all the isolates and it did not identify 5% of isolates. From the small panel, a total of 89% of isolates were identified correctly and it could not identify 11% of isolates. Reduced number of assimilation tests to 13 from the large panel bought reduction in identification percentage rate by only 6%. It is impossible for many bacterial diagnostic labs worldwide to perform large panel of carbon utilization tests in routine practice. Simplified panel of assimilation tests suggested here seems to be the best alternative method for identification of Acinetobacter species.

Acinetobacter↗
PubMed1989

Histopathological classification of childhood rhabdomyosarcoma: a report from the International Society of Pediatric Oncology pathology panel.

Five hundred thirteen soft tissue tumours of childhood referred to the International Society of Pediatric Oncology (SIOP) Rhabdomyosarcoma study have been reviewed. The period covered was from January 1975 to December 1983. Three hundred thirty-nine neoplasms were regarded as embryonal rhabdomyosarcoma. The histological diagnosis of all referred tumours is given, and a classification of rhabdomyosarcomas developed during the course of the study is described. The relationship between histological subtypes and aspects of clinical behaviour is presented. The classification is thought to be helpful in diagnosis and also in assessment of the likelihood of recurrence and/or metastasis of childhood rhabdomyosarcoma.

Adolescent↗
PubMed1996

An evaluation of the accuracy of four ELISA methods for measuring natural and recombinant human interferon-g.

We describe an evaluation of four ELISA methods, including three commercial kits, for measuring recombinant and natural human interferon-g (hIFN-g). Using a panel of samples, including well-characterized reference standards, we compared relative quantification between assays, within assays and, where possible, the absolute accuracy of quantification as compared to other analytical methods. The four assays generated markedly different results; up to an almost 60-fold difference between the highest and lowest values for one sample. The differences between assays were not necessarily predictable. No single correction factor could be determined to correct results from one method to another across the panel of samples tested. We conclude that investigators should be diligent to revalidate commercial methods before depending on such methods and resultant data.

Amino Acid Sequence↗
PubMed1996

An algorithm for the grading of activity in chronic hepatitis C. The METAVIR Cooperative Study Group.

Histological activity reflects the global assessment of basic necroinflammatory lesions and is a criterion of major importance in chronic hepatitis C. The aim of this study was to propose and test the accuracy of a simple algorithm that generates a single activity score based on basic pathological features. A panel of 10 pathologists reviewed 363 chronic hepatitis C liver biopsies and graded the activity of hepatitis according to their own experience (reference activity). Then, a consensual algorithm on the grading of activity was established by the 10 experts in a panel discussion. Finally, stepwise discriminant analysis was performed to define which basic features had been intuitively used in the reference activity (statistical activity). To test the accuracy of the algorithm, concordance between the activity defined by the algorithm and the reference activity was assessed. It was compared with concordance between the activity defined by the statistical model and the reference activity. The algorithm proposed by the panel for the grading of activity included piecemeal necrosis and lobular necrosis. Concordance between reference activity and activity defined by the algorithm was substantial (305 cases, 84%, kappa = .75). Discriminant analysis showed that piecemeal necrosis, lobular necrosis, and portal inflammation were independently used to grade the activity. Concordance between reference activity and activity defined by the statistical model was substantial (300 cases, 83%, kappa = .73), virtually identical to the concordance between reference activity and activity defined by algorithm. This study proposes a simple algorithm for the grading of activity in chronic hepatitis. Its accuracy is as high as that obtained using a statistical approach.

Algorithms↗
PubMedDate not supplied

The use of the Delphi panel for consensus development on indicators of laboratory performance.

The objective of this research study is to identify laboratory performance areas and indicators of performance from the perspective of key laboratory constituencies. A specific technique, the Delphi panel, is used to achieve consensus on a system of indicators that can be used by laboratory service managers to build information pathways, increase efficiency, and improve outcomes. Individual panels represented the five highest ranked stakeholder groups: hospital executives, managed care executives, referring physicians, laboratory regulators, and laboratory managers. The instruments used for the Delphi panels were developed and validated in a pilot study. After three rounds, each panel had identified a set of priority performance areas and indicators for each area. Although concurring that the Delphi was valuable and effective in identifying performance areas, participants indicated that it was less useful in developing specific indicators enabling monitoring of laboratory performance over time or cross-laboratory comparisons.

Consensus Statements as Topic↗
PubMed1995

A strategy for constructing high-resolution genetic maps of the human genome: a genetic map of chromosome 17p, ordered with meiotic breakpoint-mapping panels.

Genetic linkage analyses with genotypic data obtained from four CEPH reference families initially assigned 24 new PCR-based markers to chromosome 17 and located the markers at specific intervals of an existing genetic map of chromosome 17p. Each marker was additionally genotyped with an ordered set of obligate, phase-known recombinant chromosomes. The breakpoint-mapping panels for each family consisted of two parents, one sib with a nonrecombinant chromosome, and one or more sibs with obligate recombinant chromosomes. The relative order of markers was determined by sorting segregation patterns of new markers and ordered anchor markers and by minimizing double-recombination events. Consistency of segregation patterns with multiple flanking loci constituted support for order. A genetic map of chromosome 17p was completed with 39 markers in 23 clusters, with an average space of 3 cM between clusters. The collection of informative genotypes was highly efficient, requiring fivefold fewer genotypes than would be collected with all the CEPH families. Given the availability of large numbers of highly informative PCR-based markers, meiotic breakpoint mapping should facilitate construction of a human genomic map with 1-cM resolution.

Base Sequence↗