Nonisotopic detection of human papillomavirus DNA in clinical specimens using a consensus PCR and a generic probe mix in an enzyme-linked immunosorbent assay format

We assessed the value of a new digoxigenin (DIG)-labeled generic probe mix in a PCR-enzyme-linked immunosorbent assay format to screen for the presence of human papillomavirus (HPV) DNA amplified from clinical specimens. After screening with this new generic assay is performed, HPV DNA-positive samples can be directly genotyped using a reverse blotting method with product from the same PCR amplification. DNA from 287 genital specimens was amplified via PCR using biotin-labeled consensus primers directed to the L1 gene. HPV amplicons were captured on a streptavidin-coated microwell plate (MWP) and detected with a DIG-labeled HPV generic probe mix consisting of nested L1 fragments from types 11, 16, 18, and 51. Coamplification and detection of human DNA with biotinylated beta-globin primers served as a control for both sample adequacy and PCR amplification. All specimens were genotyped using a reverse line blot assay (13). Results for the generic assay using MWPs and a DIG-labeled HPV generic probe mix (DIG-MWP generic probe assay) were compared with results from a previous analysis using dot blots with a radiolabeled nested generic probe mix and type-specific probes for genotyping. The DIG-MWP generic probe assay resulted in high intralaboratory concordance in genotyping results (88% versus 73% agreement using traditional methods). There were 207 HPV-positive results using the DIG-MWP method and 196 positives using the radiolabeled generic probe technique, suggesting slightly improved sensitivity. Only one sample failed to test positive with the DIG-MWP generic probe assay in spite of a positive genotyping result. Concordance between the two laboratories was nearly 87%. Approximately 6% of samples that were positive or borderline when tested with the DIG-MWP generic probe assay were not detected with the HPV type-specific panel, perhaps representing very rare or novel HPV types. This new method is easier to perform than traditional generic probe techniques and uses more objective interpretation criteria, making it useful in studies of HPV natural history.

Characterization of the Drosophila caspase, DAMM

Caspases are main effectors of apoptosis in metazoans. Genome analysis indicates that there are seven caspases in Drosophila, six of which have been previously characterized. Here we describe the cloning and characterization of the last Drosophila caspase, DAMM. Similar to mammalian effector caspases, DAMM lacks a long prodomain. We show that the DAMM precursor, along with the caspases DRONC and DECAY, is partially processed in cells undergoing apoptosis. Recombinant DAMM produced in Escherichia coli shows significant catalytic activity on a pentapeptide caspase substrate. Low levels of damm mRNA are ubiquitously expressed in Drosophila embryos during early stages of development. Relatively high levels of damm mRNA are detected in larval salivary glands and midgut, and in adult egg chambers. Ectopic expression of DAMM in cultured cells induces apoptosis, and similarly, transgenic overexpression of DAMM, but not of a catalytically inactive DAMM mutant, in Drosophila results in a rough eye phenotype. We demonstrate that expression of the catalytically inactive DAMM mutant protein significantly suppresses the rough eye phenotype due to the overexpression of HID, suggesting that DAMM may be required in a hid-mediated cell death pathway.

Easing the path back to nursing practice

With staff shortages reaching crisis level, the government is keen to encourage back nurses who have taken a career break. For one nurse, this has worked well.

STRICA, a novel Drosophila melanogaster caspase with an unusual serine/threonine-rich prodomain, interacts with DIAP1 and DIAP2

The recently published genome sequence of Drosophila melanogaster predicts seven caspases in the fly. Five of these caspases have been previously characterised. Here, we describe the Drosophila caspase, STRICA. STRICA is a caspase with a long amino-terminal prodomain that lacks any caspase recruitment domain or death effector domain. Instead, the prodomain of STRICA consists of unique serine/threonine stretches. Low levels of strica expression were detected in embryos, larvae, pupae and adult animals. STRICA is a cytoplasmic protein that, upon overexpression, caused apoptosis in cultured Drosophila SL2 cells that was partially suppressed by DIAP1. Interestingly, unlike other fly caspases, STRICA showed physical association with DIAP2, in cotransfection experiments. These results suggest that STRICA may have a unique cellular function.

Surgical outcomes of a randomized prospective trial involving patients with a proximal femoral fracture

BACKGROUND

An orthopaedic management/patient-focused care unit (OMPFCU) involving a dedicated orthopaedic-geriatrics liaison team was established at the Royal Brisbane Hospital in 1994 in an effort to safely accelerate rehabilitation of patients with proximal femoral fractures.

METHODS

The surgical outcomes of the patients were monitored in order to determine whether accelerated rehabilitation had any significant adverse effects on the surgical outcomes, measured by mortality, readmission to hospital, deep wound infection, fracture union delay, mobility and the revision surgery rate.

RESULTS

No significant difference was recorded in mortality and morbidity, deep wound infection and revision surgery rates between patients in the Royal Brisbane Hospital OMPFCU and those in standard care in the orthopaedic surgery wards.

CONCLUSION

Accelerated rehabilitation for patients with a proximal femoral fracture in a major teaching hospital can be accomplished safely.

An essential role for the caspase dronc in developmentally programmed cell death in Drosophila

Dronc is a caspase recruitment domain-containing Drosophila caspase that is expressed in a temporally and spatially restricted fashion during development. Dronc is the only fly caspase known to be regulated by the hormone ecdysone. Here we show that ectopic expression of dronc in the developing fly eye leads to increased cell death and an ablated eye phenotype that can be suppressed by halving the dosage of the genes in the H99 complex (reaper, hid, and grim) and enhanced by mutations in diap1. In contrast to previous reports, we show that the dronc eye ablation phenotype can be suppressed by coexpression of the baculoviral caspase inhibitor p35. Dronc also interacts, both genetically and biochemically, with the CED-4/Apaf-1 fly homolog, Dark. Furthermore, extracts made from Dark homozygous mutant flies have reduced ability to process Dronc, showing that Dark is required for Dronc processing. Finally, using the RNA interference technique, we show that loss of Dronc function in early Drosophila embryos results in a dramatic decrease in cell death, indicating that Dronc is important for programmed cell death during embryogenesis. These results suggest that Dronc is a key caspase mediating programmed cell death in Drosophila.

Tissue-specific regulation of cyclin E transcription during Drosophila melanogaster embryogenesis

Cyclin E is an essential regulator of S phase entry. We have previously shown that transcriptional regulation of the gene that encodes Drosophila cyclin E, DmcycE, plays an important role in the control of the G(1) to S phase transition during development. We report here the first comprehensive analysis of the transcriptional regulation of a G(1)phase cell cycle regulatory gene during embryogenesis. Analysis of deficiencies, a genomic transformant and reporter gene constructs revealed that DmcycE transcription is controlled by a large and complex cis-regulatory region containing tissue- and stage-specific components. Separate regulatory elements for transcription in epidermal cells during cell cycles 14–16, central nervous system cells and peripheral nervous system cells were found. An additional cis-regulatory element drives transcription in thoracic epidermal cells that undergo a 17th cell cycle when other epidermal cells have arrested in G(1)phase prior to terminal differentiation. The complexity of DmcycE transcriptional regulation argues against a model in which DmcycE transcription is regulated simply and solely by G(1) to S phase transcription regulators such as RB, E2F and DP. Rather, our study demonstrates that tissue-specific transcriptional regulatory mechanisms are important components of the control of cyclin E transcription and thus of cell proliferation in metazoans.

Prenatal education for mothers with disabilities

Prenatal nurse educators are well prepared to meet the learning needs of many expectant mothers. But how prepared are they to meet the learning needs of mothers with disabilities? To answer this question, eight mothers with various chronic illnesses located in north-eastern Ontario, Canada were asked to describe their maternity experiences. Given the small convenience sample and exploratory nature of the study, a qualitative content analysis was done. The mothers' reports described interaction with a variety of health professionals. This analysis focuses on findings specific to nurses who provide prenatal education. In general, mothers reported they had received insufficient, inappropriate information, especially about their pregnancy and chronic illnesses. The mothers thought that nurses doubted the ability of women with disabilities to be decision-makers or responsible and 'proper' mothers. Suggestions by disabled mothers for quality care in prenatal education are described. A more emancipatory approach to preparing nurses for practice as prenatal educators is recommended. Such an approach can reduce the barriers associated with power differences between women with disabilities as 'learners' and their nurse 'teachers'.

Determinants of low-risk and high-risk cervical human papillomavirus infections in Montreal University students

BACKGROUND

Previous studies have been inconsistent about the degree of sexual transmissibility of cervical human papillomavirus (HPV) infection. The authors hypothesize that risk factors for HPV infection vary according to HPV type.

GOAL

To estimate the prevalence of HPV infection in asymptomatic women and to identify risk factors for overall HPV infection and HPV infection by oncogenic and nononcogenic type.

STUDY DESIGN

A cross-sectional survey was conducted at the McGill University clinic in Montreal. Cervical specimens were collected from 489 female students presenting at the clinic for a routine Papanicolaou test. Data on potential risk factors was obtained by questionnaire. Human papillomavirus DNA was detected by the polymerase chain reaction using consensus primers (MY09/11) followed by hybridization with generic and type-specific probes using Southern blot and dot blot techniques.

RESULTS

The overall HPV prevalence was 21.8%. A low-risk HPV infection was found in 6.2% of the women, 11.8% had a high-risk HPV infection (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58), 7.1% had an unknown HPV type, and 2.7% had a multiple type infection. Two profiles emerged for sexual activity and risk of HPV infection according to oncogenic risk after multivariate analysis. Lifetime frequency of sexual intercourse and lifetime number of oral sex partners was associated with high-oncogenic-risk HPV infections; however, HPV infection with low-oncogenic-risk types was invariant with respect to markers of sexual activity.

CONCLUSION

These results suggest that there are differences in epidemiologic correlates of transmission between low-risk and high-oncogenic-risk HPV types based on oncogenicity. This finding has important implications for primary prevention of HPV infection and cervical cancer precursors.

External quality assessment in the examination of blood films for malarial parasites within Ontario, Canada

OBJECTIVE

To assess laboratory practice in the examination of blood films for malarial parasites.

METHOD

Ontario medical laboratories, licensed by the Ministry of Health, are required to participate in external quality assessment by the Laboratory Proficiency Testing Program, which assesses performance of laboratory assays and also examines the total testing process. Educational strategies are used to improve performance.

RESULTS

A 1995 survey indicated shortcomings in detection and identification of malarial parasites in blood films. Consequently, recommendations for the investigation of malarial parasites in blood were issued. In 1996 and 1997, 16 workshops were conducted. A 1997 follow-up external quality assessment survey indicated that problems persist as 27% of laboratories failed to correctly speciate Plasmodium falciparum. Good Practice Guidelines were issued in 1998.

CONCLUSION

Further education and assessment are required. Laboratories lacking expertise must establish referral arrangements with more proficient laboratories.

Laboratory medicine in Ontario: its downsizing and the consequences on quality

Health care in Ontario consumes 35% of provincial government annual revenues. Fiscal constraint mandates restructuring of health services to maintain a fully, publicly-funded universally-accessible health system that is patient-focussed and health-outcome driven. Acute-care hospital restructuring under the authority of the Health Services Restructuring Commission and primary health-care reform characterise present government initiatives. Laboratory medicine services at about Can $1 billion annually account for about 5% of health expenditure. A Laboratory Services Restructuring Secretariat created by the Ministry of Health in 1995 has planned regionally-based integrated laboratory services systems bringing together public and private providers, designed a province-wide laboratory information system, developed a quality management program, reviewed the human resource needs for laboratory physicians, scientists and technologists, and recommended that the legislation be rewritten so as to be enabling - not controlling. Meanwhile both hospital and private laboratories have closed, leaving 296 in 1998 compared to 394 in 1991. Laboratory physician numbers at 39 per million population falls far short of the recommended target of 52 and many are within 10 years of retirement. Renewal of laboratory physicians and scientists to meet the shortfall is not occurring. The numbers of registered laboratory technologists has fallen by 6. 8% over 2 years. Consolidation and downsizing of laboratories with the formation of core laboratories has resulted in multi-discipline and cross discipline tasking of specialist technologists. Senior and middle level management technologists have been declared redundant. As a consequence, quality control practices have been hard hit. Plans to address these deficiencies through regional integration and sharing of resources remain to be implemented.

DECAY, a novel Drosophila caspase related to mammalian caspase-3 and caspase-7

Caspases are key effectors of programmed cell death in metazoans. In Drosophila, four caspases have been described so far. Here we describe the identification and characterization of the fifth Drosophila caspase, DECAY. DECAY shares a high degree of homology with the members of the mammalian caspase-3 subfamily, particularly caspase-3 and caspase-7. DECAY lacks a long prodomain and thus appears to be a class II effector caspase. Ectopic expression of DECAY in cultured cells induces apoptosis. Recombinant DECAY exhibited substrate specificity similar to the mammalian caspase-3 subfamily. Low levels of decay mRNA are ubiquitously expressed in Drosophila embryos during early stages of development but its expression becomes somewhat spatially restricted in some tissues. During oogenesis decay mRNA was detected in egg chambers of all stages consistent with a role for DECAY in apoptosis of nurse cells. Relatively high levels of decay mRNA are expressed in larval salivary glands and midgut, two tissues which undergo histolysis during larval/pupal metamorphosis, suggesting that DECAY may play a role in developmentally programmed cell death in Drosophila.

An interprovincial external quality assessment of the ability of Canadian laboratories to detect the vancomycin and penicillin resistance of Enterococcus faecium D366

OBJECTIVE: To evaluate the ability of Canadian laboratories to identify enterococci and detect low-level resistance to penicillin, ampicillin and vancomycin in five provinces and two territories by two external quality assessment schemes. METHODS: Enterococcus faecium, strain D366, with minimum inhibitory concentrations for vancomycin and penicillin of 32 and 16 mg/L respectively, was distributed during a routine proficiency survey. Laboratories were required to culture and identify the isolate and to test antimicrobial susceptibility. Participants were assessed against consensus reference values. RESULTS: Three hundred and sixty-four hospital, commercial and public-health laboratories participated, using their established procedures for patient samples. The isolate was identified to the species level by 222 (61%) laboratories and to the genus level by a further 98 participants. Forty-four failed to meet the expected standard. Vancomycin resistance was detected by 94%. Those reporting a falsely susceptible result used disk diffusion testing. Penicillin resistance was noted by 250 of 258 laboratories reporting on this agent. An incorrect ampicillin-susceptible finding was reported by 62 of 147 laboratories using automated microdilution or agar dilution methods. CONCLUSIONS: Most laboratories identified the isolate to an appropriate level. Detection of low-level vancomycin and penicillin resistance was achieved by the majority. Ampicillin resistance was less readily detected.

Nonisotopic detection and typing of human papillomavirus DNA in genital samples by the line blot assay. The Canadian Women's HIV study group

The line blot assay, a gene amplification method that combines PCR with nonisotopic detection of amplified DNA, was evaluated for its ability to detect human papillomavirus (HPV) DNA in genital specimens. Processed samples were amplified with biotin-labeled primers for HPV detection (primers MY09, MY11, and HMB01) and for beta-globin detection (primers PC03 and PC04). Amplified DNA products were hybridized by a reverse blot method with oligonucleotide probe mixtures fixed on a strip that allowed the identification of 27 HPV genotypes. The line blot assay was compared to a standard consensus PCR test in which HPV amplicons were detected with radiolabeled probes in a dot blot assay. Two hundred fifty-five cervicovaginal lavage specimens and cervical scrapings were tested in parallel by both PCR tests. The line blot assay consistently detected 25 copies of HPV type 18 per run. The overall positivity for the DNA of HPV types detectable by both methods was 37.7% (96 of 255 samples) by the line blot assay, whereas it was 43. 5% (111 of 255 samples) by the standard consensus PCR assay. The sensitivity and specificity of the line blot assay reached 84.7% (94 of 111 samples) and 98.6% (142 of 144 samples), respectively. The agreement for HPV typing between the two PCR assays reached 83.9% (214 of 255 samples). Of the 37 samples with discrepant results, 33 (89%) were resolved by avoiding coamplification of beta-globin and modifying the amplification parameters. With these modifications, the line blot assay compared favorably to an assay that used radiolabeled probes. Its convenience allows the faster analysis of samples for large-scale epidemiological studies. Also, the increased probe spectrum in this single hybridization assay permits more complete type discrimination.

DRONC, an ecdysone-inducible Drosophila caspase

Caspases play an essential role in the execution of programmed cell death in metazoans. Although 14 caspases are known in mammals, only a few have been described in other organisms. Here we describe the identification and characterization of a Drosophila caspase, DRONC, that contains an amino terminal caspase recruitment domain. Ectopic expression of DRONC in cultured cells resulted in apoptosis, which was inhibited by the caspase inhibitors p35 and MIHA. DRONC exhibited a substrate specificity similar to mammalian caspase-2. DRONC is ubiquitously expressed in Drosophila embryos during early stages of development. In late third instar larvae, dronc mRNA is dramatically up-regulated in salivary glands and midgut before histolysis of these tissues. Exposure of salivary glands and midgut isolated from second instar larvae to ecdysone resulted in a massive increase in dronc mRNA levels. These results suggest that DRONC is an effector of steroid-mediated apoptosis during insect metamorphosis.

An overview of quality control practices in Ontario with particular reference to cholesterol analysis

BACKGROUND

The Laboratory Proficiency Testing Program (LPTP) assesses the analytical performance of all licensed laboratories in Ontario. The LPTP Enzymes, Cardiac Markers, and Lipids Committee conducted a "Patterns of Practice" survey to assess the in-house quality control (QC) practices of laboratories in Ontario using cholesterol as the QC paradigm.

DESIGN AND METHODS

The survey was questionnaire-based seeking information on statistical calculations, software rules, review process and data retention, and so on. Copies of the in-house cholesterol QC graphs were requested. A total of 120 of 210 laboratories were randomly chosen to receive the questionnaires during 1995 and 1996; 115 laboratories responded, although some did not answer all questions.

RESULTS

The majority calculate means and standard deviations (SD) every month, using anywhere from 4 to >100 data points. 65% use a fixed mean and SD, while 17% use means calculated from the previous month. A few use a floating or cumulative mean. Some laboratories that do not use fixed means use a fixed SD. About 90% use some form of statistical quality control rules. The most common rules used to detect random error are 1(3s)/R4s while 2(2s)/4(1s)/10x are used for systematic errors. About 20% did not assay any QC at levels >5.5 mmol/L.

CONCLUSIONS

Quality control data are reviewed daily (technologists), weekly and monthly (supervisors/directors). Most laboratories retain their QC records for up to 3 years on paper and magnetic media. On some QC graphs the mean and SD, QC product lot number, or reference to action logs are not apparent. Quality control practices in Ontario are, therefore, disappointing. Improvement is required in the use of clinically appropriate concentrations of QC material and documentation on QC graphs.

decapentaplegic is required for arrest in G1 phase during Drosophila eye development

During eye development in Drosophila, cell cycle progression is coordinated with differentiation. Prior to differentiation, cells arrest in G1 phase anterior to and within the morphogenetic furrow. We show that Decapentaplegic (Dpp), a TGF-β family member, is required to establish this G1 arrest, since Dpp-unresponsive cells located in the anterior half of the morphogenetic furrow show ectopic S phases and ectopic expression of the cell cycle regulators Cyclins A, E and B. Conversely, ubiquitous over-expression of Dpp in the eye imaginal disc transiently inhibits S phase without affecting Cyclin E or Cyclin A abundance. This Dpp-mediated inhibition of S phase occurs independently of the Cyclin A inhibitor Roughex and of the expression of Dacapo, a Cyclin E-Cdk2 inhibitor. Furthermore, Dpp-signaling genes interact genetically with a hypomorphic cyclin E allele. Taken together our results suggest that Dpp acts to induce G1 arrest in the anterior part of the morphogenetic furrow by a novel inhibitory mechanism. In addition, our results provide evidence for a Dpp-independent mechanism that acts in the posterior part of the morphogenetic furrow to maintain G1 arrest.

Analysis of a Drosophila cyclin E hypomorphic mutation suggests a novel role for cyclin E in cell proliferation control during eye imaginal disc development

We have generated and characterized a Drosophila cyclin E hypomorphic mutation, DmcycEJP, that is homozygous viable and fertile, but results in adults with rough eyes. The mutation arose from an internal deletion of an existing P[w+lacZ] element inserted 14 kb upstream of the transcription start site of the DmcycE zygotic mRNA. The presence of this deleted P element, but not the P[w+lacZ] element from which it was derived, leads to a decreased level of DmcycE expression during eye imaginal disc development. Eye imaginal discs from DmcycEJP larvae contain fewer S phase cells, both anterior and posterior to the morphogenetic furrow. This results in adults with small rough eyes, largely due to insufficient numbers of pigment cells. Altering the dosage of the Drosophila cdk2 homolog, cdc2c, retinoblastoma, or p21(CIP1) homolog dacapo, which encode proteins known to physically interact with Cyclin E, modified the DmcycEJP rough eye phenotype as expected. Decreasing the dosage of the S phase transcription factor gene, dE2F, enhanced the DmcycEJP rough eye phenotype. Surprisingly, mutations in G2/M phase regulators cyclin A and string (cdc25), but not cyclin B1, B3, or cdc2, enhanced the DmcycEJP phenotype without affecting the number of cells entering S phase, but by decreasing the number of cells entering mitosis. Our analysis establishes the DmcycEJP allele as an excellent resource for searching for novel cyclin E genetic interactors. In addition, this analysis has identified cyclin A and string as DmcycEJP interactors, suggesting a novel role for cyclin E in the regulation of Cyclin A and String function during eye development.

Proficiency testing of creatine kinase and creatine kinase-2: the experience of the Ontario Laboratory Proficiency Testing Program

The Ontario Laboratory Proficiency Testing Program has regularly monitored the analytical performance of total creatine kinase (CK) (approximately 230 participants) and CK isoenzyme-2 (CK-MB) (approximately 160 participants) throughout the entire province. Consistently, a wide dispersion of results has been observed not only between different analyzer systems but also among identical analyzers. Accordingly, the results of the last three proficiency surveys for these analytes were examined statistically to establish both the extent of these variations and the range of values reported for the male upper reference ranges. The results of many of the analyzer systems were significantly different from each other, as were many of the reference ranges. This unsatisfactory situation may only be remedied by the use of reference materials as shown by others. The consequences of these findings also effect the reliability of epidemiological surveys such as the WHO MONICA Project (Circulation 1994;90:583-612), which monitors deaths due to heart disease and includes cardiac enzyme results in its criteria.

A natural survey of audit activity across the primary-secondary care interface

OBJECTIVE

To document the nature of audit activity at the primary-secondary care interface; to explore participants' experiences of undertaking such interface audit; to identify factors associated with these experiences; and to gather views on future interface audit activities.

DESIGN

A three phase national survey by postal questionnaire with a cascade sampling approach.

SETTING

England and Wales.

RESULTS

Response rates were: 65% to the first questionnaire; 34% to the second questionnaire; and 45% to the third questionnaire. 56% of the audits covered some element of management of patients or disease; only 33% of the audits were within a single topic area. Most audits had more than one trigger: for 61% the trigger was a perceived problem; for 58% it was of mutual interest. Only 18% of audits were initiated collaboratively; doctors were the most frequent initiators (72%), and most audits (63%) involved collaborative groups convened specifically for the audit. 58% of groups had between three and eight members, 23% had 12 or more. Doctors were the most frequent group members. There was differential involvement of group members in various group tasks; the setting of guidelines was highly dominated by doctors. Of reportedly complete audits, only two fifths had implemented change and only a quarter had evaluated this change. There was widespread feeling of successful group work, with evidence of benefit in terms of the two sectors of care being able to consider issues of mutual concern. Levels of understanding of the group task and of participation were positively related to the duration of meetings. Joint initiation of audits facilitated greater understanding of the group task. Larger group sizes allowed primary and secondary carers to discuss issues of common concern; however, larger groups were more likely to experience disagreements. Having previously worked with group members increased trust and good working relations. The main lessons learnt from the experience included the importance of setting clear objectives and good communications between primary and secondary carers. Factors identified as important for future audit activity at the primary-secondary care interface included commitment, enthusiasm, time, and money.

CONCLUSIONS

Audit at the primary-secondary care interface is taking place on a wide scale and has been an enjoyable experience for most of the respondents in this study.

IMPLICATIONS

Despite being a positive experience most audits stopped short of implementing change. Care must be taken to complete the audit cycle if audit at the primary-secondary care interface is to move beyond the roles of education and professional development and to fulfil its potential in improving the quality of care.

Four Arabidopsis RPP loci controlling resistance to the Noco2 isolate of Peronospora parasitica map to regions known to contain other RPP recognition specificities

Interactions between Arabidopsis thaliana and the downy mildew fungus Peronospora parasitica provide a model system to study the genetic and molecular basis of plant-pathogen recognition. With the use of the Noco2 isolate of P. parasitica, the reaction phenotypes of 46 accessions of Arabidopsis were examined and 31 accessions exhibited resistance. Resistance phenotypes examined ranged from distinct necrotic pits or flecks to a weak necrosis accompanied by late and sparse fungal sporulation. Segregating populations generated from crosses between the susceptible accession Col-0 and the resistant accessions Ws-0, Pr-0, Oy-0, Po-1, Bch-1, Ge-1, Di-1, Ji-1, and Te-0 were also screened with Noco2. The genetic data were consistent with the presence of single resistance (RPP) loci in all of these accessions except Oy-0, in which resistance was inherited as a digenic trait. As a first step to molecular cloning, the map positions of four resistance loci were determined. These have been designated RPP14.1 from Ws-0, RPP14.2 from Pr-O, and RPP14.3 and RPP5.2 from Oy-0. RPP14.1 was mapped to a 3.2-cM interval on chromosome 3 that is linked to a region between the markers Gl-1 and m249 known to contain other P. parasitica resistance specificities. RPP14.2 from Pr-0 and RPP14.3 from Oy-0 were also positioned in this interval. Moreover, RPP14.1 and RPP14.2 showed linkage of < 0.05 cM, suggesting possible allelism. The second RPP locus from Oy-0, RPP5.2, was located on chromosome 4 and exhibited strong linkage (< 2 cM) to RRP5.1, a locus previously identified in the Arabidopsis accession Landsberg-erecta. The results reinforce evidence for RPP gene clustering in the Arabidopsis genome and provide new targets for cloning and examination of RPP gene structure, function, allelic variation, and organization within defined loci.

Quality improvement of diagnostic microbiology through a peer-group proficiency assessment program. A 20-year experience in Ontario. The Microbiology Committee

OBJECTIVE

To evaluate the microbiology laboratory performance in Ontario over a 20-year period of participation in a quality assessment program and to assess the impact of quality improvement strategies.

DESIGN

Longitudinal review of isolation, identification, and antimicrobial susceptibility testing of bacteria from lyophilized, simulated patient samples.

SETTING

Ontario medical laboratories, licensed by the Ministry of Health, have been subjected to mandatory testing by the Laboratory Proficiency Testing Program of the Ontario Medical Association since 1974. Survey reports, information bulletins, correspondence, on-site consultations, educational assistance tutorials, and teleconference education are used as quality improvement strategies.

PARTICIPANTS AND INTERVENTIONS

Laboratories were subjected annually to 20 external quality assessment challenges. Performance was assessed against consensus reference values. Single survey and cumulative profiles were reviewed by a peer-group panel for acceptable or unacceptable performance. Specific interventions are used to improve collective and individual laboratory performance.

RESULTS

The number of microbiology laboratories declined from 335 in 1974 to 190 in 1994. Twenty-one percent failed expected performance standards on initial review. One hundred forty-two on-site consultations and 61 educational assistance tutorials have been provided. Twenty-five laboratories were declared nonproficient. Since 1989, 50% of the laboratories have scored at or above 80% for isolation and identification, but 25% have scored at or below 50% on susceptibility testing, and 10% or fewer have scored at or above 80%. Poor susceptibility testing performance is due to inappropriate agent selection, not testing errors.

CONCLUSIONS

The emphasis of the Laboratory Proficiency Testing Program is on quality improvement, not punishment. Performance has improved, but poor performers have the same characteristics as in 1974. Identification to species is common owing to the use of commercial systems. Automated susceptibility testing has increased to 45% of participants.