Late first-trimester ultrasound findings can alter management after high-risk NIPT result

OBJECTIVE

To evaluate the impact of detailed late first-trimester ultrasound (LFTU) on the positive predictive value (PPV) of a high-risk non-invasive prenatal test (NIPT) result for various chromosomal abnormalities.

METHODS

This was a retrospective study of all cases undergoing invasive prenatal testing from three tertiary providers of obstetric ultrasound over 4 years, each using NIPT as a first-line screening test. Data were collected from pre-NIPT ultrasound, NIPT, LFTU, placental serology and later ultrasound examinations. Prenatal testing for chromosomal abnormalities was performed by microarray, initially using array comparative genomic hybridization and then single nucleotide polymorphism (SNP) array for the last 2 years. Uniparental disomy testing was performed by SNP array during all 4 years. The majority of NIPT tests were analyzed using the Illumina platform, initially confined to the assessment of the common autosomal trisomies, sex chromosome aneuploidies and rare autosomal trisomies (RAT), then extending to genome-wide analysis for the last 2 years.

RESULTS

Amniocentesis or chorionic villus sampling (CVS) was performed on 2657 patients, 1352 (51%) of whom had undergone prior NIPT, with 612 (45%) of these returning a high-risk result and meeting the inclusion criteria for the study. LFTU findings significantly affected the PPV of the NIPT result for trisomies 13 (T13), 18 (T18) and 21 (T21), monosomy X (MX) and RAT but not for the other sex chromosomal abnormalities or segmental imbalances (> 7 Mb). Abnormal LFTU increased the PPV close to 100% for T13, T18, T21, MX and RAT. The magnitude of the change in PPV was highest for the most severe chromosomal abnormalities. When LFTU was normal, the incidence of confined placental mosaicism (CPM) was highest in those with a high-risk NIPT result for T13, followed by T18 and T21. After normal LFTU, the PPV for T21, T18, T13 and MX decreased to 68%, 57%, 5% and 25%, respectively.

CONCLUSIONS

LFTU after a high-risk NIPT result can alter the PPV for many chromosomal abnormalities, assisting counseling regarding invasive prenatal testing and pregnancy management. The high PPVs of NIPT for T21 and T18 are not sufficiently modified by normal LFTU findings to alter management. These at-risk patients should be offered CVS for earlier diagnosis, particularly given the low rate of CPM associated with these aneuploidies. Patients with a high-risk NIPT result for T13 and normal LFTU findings often wait for amniocentesis or avoid invasive testing altogether given the low PPV and higher rate of CPM in this context. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Influence of fibroids on cell-free DNA screening accuracy

OBJECTIVE

Cell-free DNA (cfDNA) screening assesses both maternal and placental cfDNA. Fibroids are common and release cfDNA into maternal serum. Genetic abnormality is seen in 50% of fibroids. We aimed to assess the impact of fibroids on the accuracy of genome-wide cfDNA screening.

METHODS

This was a prospective cohort study of singleton pregnancies examined at one of two centers in Melbourne and Sydney, Australia, between 1 November 2019 and 31 December 2020. All cases underwent pretest ultrasound examination to confirm an ongoing pregnancy of at least 10 weeks' gestation, and, at this stage, the number and volume of any uterine fibroid were documented. Genome-wide cfDNA screening was performed to detect all copy-number variants (CNV) > 7 megabases. The incidence of a false-positive result was compared between cases with and those without fibroids.

RESULTS

Over the 14-month study period, 13 184 patients underwent cfDNA screening, of whom 1017 (7.7%) had fibroids. Fibroids were not identified in any of the 17 participants who had a false-positive result for chromosomes 13, 18, 21, X or Y. Ninety-five (0.7%) cases were screen-positive for subchromosomal aberration (SA), rare autosomal trisomy (RAT) or multiple abnormalities (MA), with 10 of these cases having a fetal genetic abnormality. The incidence of a false-positive RAT, MA or SA result was significantly higher in participants with fibroids (20/1017 (2.0%)) than in those without fibroids (64/12 167 (0.5%)). Women with fibroids were approximately six times as likely to have a false-positive result for SA, and this was associated positively with both fibroid number and volume.

CONCLUSIONS

Most women with fibroids do not have an abnormal result on genome-wide cfDNA screening. However, CNVs due to fibroids are associated with false-positive SA findings, although fibroids do not appear to influence cfDNA screening accuracy for the common autosomal trisomies or sex-chromosomal abnormalities. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Multicentre validation of point-of-care screening tool for heart failure: single-lead ECG recorded by smart stethoscope predicts low ejection fraction using artificial intelligence

Background/Introduction

Artificial intelligence (AI) applied to 12-lead ECG can identify left ventricular ejection fraction (EF) ≤35% with a sensitivity and specificity of 86.3% and 85.7%, respectively. Whether AI algorithms trained on 12-lead can accurately predict EF from single-lead ECGs (recorded by a smart stethoscope) remains unknown. This could facilitate point-of-care screening for low EF during routine clinical examination.

Purpose

First independent multicentre real-world UK National Health Service (NHS) prospective validation of 12-lead-ECG-trained AI algorithm applied to single-lead ECG recorded by a smart stethoscope, with AI algorithm tuned to detect EF ≤40%.

Methods

Prospective recruitment of unselected patients attending for echocardiography across six urban NHS hospital sites (UK). In addition to transthoracic echocardiogram (routine care), all participants had 15 seconds of supine, single-lead ECG recorded at six different positions (figure), encompassing standard anatomical positions for cardiac auscultation. A convolutional neural network (CNN) previously trained on 35,970 independent pairings of 12-lead-ECG and echocardiograms was retrained to use the single-lead ECG as input. Accuracy of CNN detection of low EF (binary ≤40%) is reported at a threshold of 0.5 against gold-standard; echo-determined percentage EF.

Results

Among 353 patients recruited (mean age 63±17; 58% male, 43.1% non-white), 309 (87.5%) had an EF >40%, and 44 (12.5%) had EF ≤40%. The best single recording position in isolation was position 3 (sensitivity 57.9% [42.2–73.6], specificity 86.3% [82.2–90.3]). Taking any of the six positions performed during the examination as predicting EF ≤40%, this achieved a sensitivity of 81.2% and specificity of 61.5%.

Conclusion(s)

In this first prospective multicentre validation study the retrained AI algorithm reliably detected low EF from single-lead ECGs acquired using a novel ECG-enabled stethoscope in standard auscultation positions. The ability to identify patients with possible low EF during routine physical examination addresses a significant unmet clinical need in point-of-care ruling in/out of heart failure, and has potential to provide broader population-level screening for asymptomatic cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Health Research, Accelerated Access Collaborative & NHSX: Artificial Intelligence in Health & Social Care Award

Triage-HF plus: 12-month study of remote monitoring pathway for triage of heart failure risk initiated during the Covid-19 pandemic

Background

The Covid-19 pandemic necessitated rapid adoption of remote monitoring across cardiovascular patient cohorts. Most patients with cardiac implantable electronic devices (CIEDs) are now able to be remotely monitored using either scheduled, patient- or threshold-triggered transmissions. The validated “Triage Heart Failure Risk Score” (Triage-HFRS) is a medical algorithm within company-specific CIEDs that can risk-stratify patients as low-, medium- or high-risk of worsening heart failure (WHF) in the next 30 days based on integrated monitoring of physiological parameters. Building on a previous proof-of-concept of the Triage-HF Plus pathway, we integrated remote data with simple 5-question telephone triage within a clinical pathway to identify WHF during the first year of the Covid-19 pandemic.

Purpose

Prospective evaluation of clinical remote monitoring pathway integrating Triage-HFRS with protocolised telephone triage (Triage-HF Plus pathway).

Methods

Prospective, real-world evaluation of clinical pathway serving a large urban region over a 12-month period, using data from April 2020 to April 2021 (initiated during the first wave of Covid-19 pandemic in the UK). From a population of 435 patients with CIEDs, 87 “high” Triage-HFRS alerts were received and patients contacted for telephone triage assessment. Screening questions were designed to identify episodes of WHF and non-HF events. Intervention was at discretion of the clinical practitioner and in line with guideline-directed practice. A consecutive sample of 115 “medium” risk scores received the same triage.

Results

Successful contact was made with 72 (82.8%) high-risk patients. Classification for high scoring patients confirmed on triage included isolated heart failure (18.3%), heart failure concurrent to medical problem (5.7%), alternative medical problem (10.3%), and recent hospital admission (8.0%); triage reassured absence of acute cause of high score in 40.2%. The sensitivity and specificity for detection of WHF was 87.9% (0.77–0.99) and 59.4% (0.50–0.69) respectively. Positive and negative predictive values were 40.3% and 94.0%, respectively. Overall accuracy was 66.2%.

Conclusions

The Triage-HF Plus pathway served as a useful remote monitoring tool for identifying patients with WHF whose care had been otherwise disrupted by the Covid-19 pandemic, allowing timely intervention and cementing the longer-term role for such models of care delivery. Crucially, in this multimorbid, high-cost population, relevant non-HF issues were also identified. The high negative predictive value further highlights the potential of proactive surveillance over conventional, periodic follow up.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Imperial Health Charity

High Pressure Liquid Chromatographic Determination of Monoand Disaccharides in Presweetened Cereals: Collaborative Study

A collaborative study was conducted using a modified AOAC method (sugars in chocolate) for the determination of fructose, glucose, sucrose, and maltose in presweetened cereals by high pressure liquid chromatography (HPLC). Eight samples consisting of 6 products were analyzed in duplicate by the HPLC method and the AOAC Lane-Eynon method. The AOAC method was modified to use water-alcohol (1 + 1) and Sep-Pak C18 cartridges for sample cleanup. The HPLC results indicate precision comparable to the Lane-Eynon method and the chocolate method. The modified HPLC method has been adopted official first action.

Farnesoid X receptor - a molecular predictor of weight loss after vertical sleeve gastrectomy?

OBJECTIVE

To determine the expression of the bile acid receptor, farnesoid X (FXR), in human gastric mucosa and investigate correlations between expression and body-mass index (BMI) and in patients with obesity, with changes in weight and BMI following vertical sleeve gastrectomy (VSG).

METHODS

Human gastric mucosa was obtained from normal/overweight individuals (macroscopically-normal tissue following surgery for malignancy) or from patients with obesity (VSG). The expression of FXR and its isoforms (FXRα, FXRβ) were examined by quantitative PCR and compared with the G protein-coupled bile acid receptor, GPBA. In patients with obesity, changes in BMI and weight loss were determined following VSG.

RESULTS

FXRα was the predominant isoform in normal/overweight individuals. FXR expression was higher in patients with obesity but GPBA receptor expression was unchanged. For those with obesity (n = 19), no correlation was found between FXR expression and change in Body-Mass Index (BMI)/month or weight loss/month, taken 3 ± 1 months after surgery, or in BMI or weight at surgery.

CONCLUSIONS

Obesity is associated with increased FXR expression in the gastric mucosa. The findings are preliminary but suggest that this increase in FXR expression is a consequence of obesity, rather than its cause.

Chronic Hepatitis C Virus Infection in Haemophilic Patients: Clinical Significance of Viral Genotype

We have undertaken a comprehensive study of hepatitis C virus (HCV) genotype and its clinical significance in haemophilic patients. 189 HCV RNA positive patients were typed, using the Simmonds classification scheme, by restriction fragment length polymorphism (RFLP) in an amplified segment of the 5 non-coding region of the HCV genome. Type 1 was found in 121 (64.0%), type 2 in 23 (12.2%), type 3 in 36 (19.0%), type 4 in 3 (1.6%), type 5 in 2 (1.1%) and mixed infection in 3 (1.6%). There were no type 6 infections and one patient (0.5%) could not be typed. Genotype was not associated with diagnosis, age, or with HIV infection. Type I was associated with higher serum HCV RNA levels, and with a poor response to interferon. Progression to hepatic decompensation has been seen less frequently in those with type 3 compared to type 1 infection (p = 0.07). Three out of eleven patients studied over a longer time course showed a change in genotype, the remainder were persistently infected with HCV type 1. In conclusion, HCV genotype has clinical relevance in the management of haemophilic patients. Those with type 1 are probably more likely to develop serious liver disease and since they respond poorly to inter- feron-α, should be considered for new treatment strategies aimed at sustained clearance of HCV RNA.

Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

PURPOSE

Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth.

METHODS

A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure.

RESULTS

The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups.

CONCLUSIONS

When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Prenatal diagnosis using combined quantitative fluorescent polymerase chain reaction and array comparative genomic hybridization analysis as a first-line test: results from over 1000 consecutive cases

OBJECTIVES

First, to assess the performance of a prenatal diagnostic service using quantitative fluorescent polymerase chain reaction (QF-PCR) and array comparative genomic hybridization (aCGH) as first-line investigations. Second, to determine the incidence of copy number variants (CNVs) by indication for testing, with particular reference to ultrasound and biochemical parameters measured in combined first-trimester screening.

METHODS

All patients undergoing invasive prenatal testing at a specialist prenatal screening service in Sydney, Australia, were included in the study. All samples underwent QF-PCR and targeted aCGH.

RESULTS

Of 1049 cases, CNVs were reported in 156 (14.9%). Preliminary QF-PCR identified abnormalities in 104 of these cases. Of the remaining 52 cases, 20 could have been detected on karyotype testing, leaving 32 cases (3.1%) with CNVs only detectable by aCGH, of which 13 (1.2%) were pathogenic. Variants of unknown significance (VOUS) were seen in only three cases. Fetal structural abnormalities identified in the first trimester were the group most likely to be associated with pathogenic CNVs (11.8%).

CONCLUSIONS

Combining QF-PCR and aCGH is an effective first-tier prenatal testing regime that does not require conventional karyotyping. The incidence of VOUS in this study was very low owing to appropriate aCGH targeting and specific reporting criteria that reduced the number of potentially difficult counseling encounters. Pathogenic CNVs are positively correlated with the presence of fetal structural abnormalities, but not with enlarged nuchal translucency or abnormal first-trimester serology results.

Canine Lymphomas

Canine lymphoma is the neoplasm most often treated by chemotherapy, yet there are few data to correlate response to therapy with its different subtypes. This study is based on biopsy specimens from 992 dogs for which lymphoma was the clinical diagnosis. All cases were phenotyped by immunohistochemistry for CD3 and CD79alpha. Cases with histiocytic proliferation were evaluated immunohistochemically for CD18. Clonality was verified in 12 cases by polymerase chain reaction (PCR). Survival (event time) data and complete survival information (cause of death or time to last follow-up) were available on 456 dogs. Additional covariate information when available included size, age, sex, phenotype, stage and grade of lymphoma, mitotic index, and treatment protocol. Because of the many subtypes of B- and T-cell lymphoma, the cases were grouped into 7 diagnostic categories: (1) benign hyperplasia; (2) low-grade B-cell; (3) high-grade B- and T-cell; (4) low-grade T-cell; (5) centroblastic large B-cell of all mitotic grades (subdivided by clinical stage); (6) immunoblastic large B-cell of all mitotic grades, and (7) high-grade peripheral T-cell. Grouping was determined by histological grade (based on mitotic rate/400× field, with low-grade 0–5, intermediate 6–10, and high-grade >10) and stage for survival function estimation. No association with survival was found for size (based on breed of dog) or sex. All diagnostic categories of indolent or low-grade type had low mitotic rates, whereas those with clinically high grades had high mitotic rates. The diagnostic category with the most cases was centroblastic large B-cell lymphoma. Compared with dogs in this largest represented group of lymphomas, dogs with high-grade lymphomas had significantly higher mortality rates, and dogs with low-grade T-cell lymphomas had significantly lower mortality rates. Treatments for high-, intermediate-, and low-grade lymphomas were divided into 4 groups: absence of treatment, chemotherapy with or without hydroxydaunorubicin, and only prednisone. Dogs with low-grade T-cell (T-zone) lymphomas had the longest median survival (622 days), whereas the shortest median survival was in dogs with T-cell high-grade (peripheral T-cell) subtype (162 days). The dogs with centroblastic large B-cell lymphomas had a median survival of 127 days with low stage, 221 days with intermediate stage, and 215 days with advanced stage. Dogs with T-zone lymphoma were probably diagnosed in later stages of disease because of the lack of signs associated with progression. As with human lymphomas, a histological diagnosis with immunophenotyping is a minimal requirement for diagnosis of a specific subtype.

Integrated overview of results from a farmlet experiment which compared the effects of pasture inputs and grazing management on profitability and sustainability

The Cicerone Project conducted a grazed farmlet experiment on the Northern Tablelands of New South Wales, Australia, from July 2000 to December 2006, to address questions raised by local graziers concerning how they might improve the profitability and sustainability of their grazing enterprises. This unreplicated experiment examined three management systems at a whole-farmlet scale. The control farmlet (farmlet B) represented typical management for the region, with flexible rotational grazing and moderate inputs. A second farmlet (farmlet A) also used flexible rotational grazing but had a higher level of pasture renovation and soil fertility, while the third farmlet (farmlet C) had the same moderate inputs as farmlet B but employed intensive rotational grazing. The present paper provides an integrated overview of the results collated from component papers and discusses the inferences that can be drawn from what was a complex, agroecosystem experiment. The measurements recorded both early and late in the experiment were tabulated for each of the farmlets and compared with each other as relative proportions, allowing visual presentation on a common, indexed scale. Because of equivalent starting conditions, there was little difference between farmlets early in the experimental period (2000–01) across a wide array of measured parameters, including herbage mass, potential pasture growth rate, liveweight, wool production per head, stocking rate, gross margin and equity. Although the experiment experienced drier-than-average conditions, marked differences emerged among farmlets over time, due to the effects of treatments. During the latter half of the experimental period (2003–06), farmlet A showed numerous positive and a few negative consequences of the higher rate of pasture renovation and increased soil fertility compared with the other two farmlets. While intensive rotational grazing resulted in superior control of gastrointestinal nematodes and slightly finer wool, this system had few effects on pastures and no positive effects on sheep liveweights, wool production or stocking rate. Whereas farmlet A showed higher gross margins, it had a negative and lower short-term cash position than did farmlets B and C, due largely to the artificially high rate of pasture renovation undertaken on this farmlet during the experiment. Although farmlet B had the highest cash position at the end of the experiment, this came at a cost of the declining quality of its pastures. Modelling of the farmlet systems allowed the results to be considered over the longer timeframes needed to assess sustainability. Thus, returns on investment were compared over realistic amortisation periods and produced outcomes based on long-term climatic expectations which were compared with those that arose under the drier-than-average conditions experienced during the experimental period. The main factors responsible for lifting the productivity of farmlet A were the sowing of temperate species and increased soil fertility, which enhanced the amount of legume and increased pasture quality and potential pasture growth. The factor that affected farmlet C most was the low proportion of the farmlet grazed at any one time, with high stock density imposed during grazing, which decreased feed intake quality. The paper concludes that more profitable and sustainable outcomes are most likely to arise from grazing enterprises that are proactively managed towards optimal outcomes by maintaining sufficient desirable perennial grasses with adequate legume content, enhancing soil fertility and employing flexible rotational grazing.

The emergence of oseltamivir-resistant pandemic influenza A(H1N1) 2009 virus amongst hospitalised immunocompromised patients in Scotland, November-December, 2009

To investigate the frequency of oseltamivir resistance in circulating strains of the 2009 influenza A(H1N1) pandemic virus in Scotland, 1,802 samples from 1,608 infected hospitalised patients were screened by the H275Y discriminatory RT-PCR. Among these, we identified 10 patients who developed the H275Y mutation. All of them were immunocompromised and were under treatment or had been treated previously with oseltamivir.

The emergence of oseltamivir-resistant pandemic influenza A (H1N1) 2009 virus amongst hospitalised immunocompromised patients in Scotland, November-December, 2009

To investigate the frequency of oseltamivir resistance in circulating strains of the 2009 influenza A(H1N1) pandemic virus in Scotland, 1,802 samples from 1,608 infected hospitalised patients were screened by the H275Y discriminatory RT-PCR. Among these, we identified 10 patients who developed the H275Y mutation. All of them were immunocompromised and were under treatment or had been treated previously with oseltamivir.

Successful treatment of Candida krusei fungemia with amphotericin B and caspofungin

We report a leukemic patient with C. krusei fungemia who failed to respond to liposomal amphotericin B therapy alone. The addition of caspofungin eradicated infection and was well tolerated. Our report is the first to describe successful treatment of a patient with invasive C. krusei infection using this combination of antifungals. Combination therapy could be a useful treatment option for invasive candidosis, particularly when caused by more resistant species such as C. krusei.

Factors associated with infection by Pseudomonas aeruginosa in adult cystic fibrosis

Cross-infection with Pseudomonas aeruginosa is an emerging issue in the care of patients with cystic fibrosis (CF). This study sought to determine the extent of, and patient factors associated with, cross-infection in a tertiary referral adult CF centre. P. aeruginosa isolates were genotyped into two groups between November 2001 and February 2003, using pulsed-field gel electrophoresis after DNA digestion by the SpeI endonuclease, and identified as clustered if there was >80% homology in the macrorestriction profiles. Patient factors and measures of disease severity were identified a priori. In total, 157 out of 227 patients had a P. aeruginosa isolate genotyped. Of these, 94 patients (60%) were infected with clustered genotypes and 47 (30%) were infected with the newly described "Midlands 1" (Md1) genotype. A further 18 patients were infected with the previously identified "Liverpool" genotype and two with the "Manchester" genotype. Logistic regression analysis revealed that the predominant predictor of infection with Md1 was age at the time of referral to the centre, suggesting that infection may have occurred prior to referral in some patients. Md1 demonstrated a relatively benign anti-biogram and did not appear to be associated with more severe disease. In conclusion, the present study provides further evidence of the emerging importance of Pseudomonas aeruginosa cross-infection in cystic fibrosis.

Differential regulation of caspase-3 by pharmacological and developmental stimuli as demonstrated using humanised caspase-3 mice

Caspase-3 is a potential therapeutic target for a number of degenerative diseases. However the development of specific caspase-3 inhibitors has been hampered by inter-species differences and the high degree of homology shared by different caspases. To circumvent these issues, we have produced and characterised a humanised caspase-3 mouse line (possessing one copy of the human gene with both copies of the murine gene disrupted) by crossing human caspase-3 transgenic mice with nullizygous caspase-3 knock-out mice. Humanised mice appeared normal and survived to adulthood. Analysis of the human gene revealed that human pro-caspase-3 was expressed in the same tissues as its murine counterpart. However humanised mice retained the hypercellularity of frontal cortex seen in their knock-out parental line and there was no biochemical evidence of human protein processing during naturally occurring neuronal death taking place during brain development. In contrast, the human protein was cleaved by the mouse machinery following anti-Fas treatment of adult mice. These data suggest that there is a fundamental difference between the activation pathways leading to caspase-3 cleavage during naturally occurring cell death in development/embryogenesis and following an apoptotic stimulus in the adult.

Association between age and knee structural change: a cross sectional MRI based study

OBJECTIVE

To describe the associations between age, knee cartilage morphology, and bone size in adults.

METHODS

A cross sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61) was studied. Knee measures included a cartilage defect five site score (0-4 respectively) and prevalence (defect score of > or =2 at any site), cartilage volume and thickness, and bone surface area and/or volume. These were determined at the patellar, medial, and lateral tibial and femoral sites using T(1)weighted fat saturation MRI. Height, weight, and radiographic osteoarthritis (ROA) were measured by standard protocols.

RESULTS

In multivariate analysis, age was significantly associated with knee cartilage defect scores (beta = +0.016 to +0.073/year, all p<0.01) and prevalence (OR = 1.05-1.10/year, all p<0.05) in all compartments. Additionally, age was negatively associated with knee cartilage thickness at all sites (beta = -0.013 to -0.035 mm/year, all p<0.05), and with patellar (beta = -11.5 microl/year, p<0.01) but not tibial cartilage volume. Lastly, age was significantly positively associated with medial and lateral tibial surface bone area (beta = +3.0 to +4.7 mm(2)/year, all p<0.05) and patellar bone volume (beta = +34.4 microl/year, p<0.05). Associations between age and tibiofemoral cartilage defect score, cartilage thickness, and bone size decreased in magnitude after adjustment for ROA, suggesting these changes are directly relevant to OA.

CONCLUSION

The most consistent knee structural changes with increasing age are increase in cartilage defect severity and prevalence, cartilage thinning, and increase in bone size with inconsistent change in cartilage volume. Longitudinal studies are needed to determine which of these changes are primary and confirm their relevance to knee OA.

Genetic mechanisms of knee osteoarthritis: a population based case-control study

OBJECTIVE

To compare subjects who had at least one parent with a total knee replacement for severe primary knee osteoarthritis with age and sex matched controls who had no family history of knee osteoarthritis

DESIGN

Population based case-control study of 188 matched pairs (mean age 45 years, range 26 to 60).

METHODS

Articular cartilage volume and bone size were determined at the patella and at the medial tibial and lateral tibial compartments by processing images acquired using T1 weighted, fat saturated magnetic resonance imaging. Radiographic osteoarthritis (ROA) was assessed from a standing semiflexed radiograph scored for joint space narrowing and osteophytosis. Knee pain was assessed by questionnaire. Height, weight, body mass index (BMI), lower limb muscle strength, and endurance fitness were measured by standard protocols.

RESULTS

Compared with the controls, index offspring had higher BMI (27.8 v 26.0 kg/m(2), p = 0.02), weaker lower limb muscles (127 v 135 kg, p = 0.006), more knee pain (47% v 22%, p<0.001), and greater medial tibial bone area (17.6 v 17.1 cm(2), p = 0.01). With the exception of BMI, these differences persisted in multivariate analysis. There was a non-significant trend to higher cartilage volume at tibial sites and increased ROA in the offspring in the total and subgroup analyses, but no difference in height and endurance fitness.

CONCLUSIONS

BMI, muscle strength, knee pain, and medial tibial bone area, but not cartilage volume, appear to play a role in the genetic regulation and development of knee osteoarthritis.

Early radiographic osteoarthritis is associated with substantial changes in cartilage volume and tibial bone surface area in both males and females

OBJECTIVE

To describe the association between early radiographic osteoarthritis of the knee (ROA), knee cartilage volume and tibial bone surface area.

METHODS

Cross-sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61). Articular cartilage volume, bone area and volume were determined at the patella, medial tibial and lateral tibial compartments by processing images acquired in the sagittal plane using T1-weighted fat saturation MRI. ROA was assessed with a standing semiflexed radiograph and the OARSI atlas for joint space narrowing and osteophytosis. Both radiographs and MRIs were performed in the right knee and read by different observers.

RESULTS

ROA (predominantly grade 1) was present in 17% of subjects of which medial joint space narrowing was most common (14%) followed by medial osteophytes (6%). Grade one medial joint space narrowing was associated with substantial reductions in cartilage volume at both the medial and lateral tibial and patellar sites within the knee (adjusted mean difference 11-13%, all P<0.001) while grade one osteophytosis was associated with substantial increases in both lateral and medial tibial joint surface area (adjusted mean difference 10-16%, all P<0.001). In contrast, osteophytosis was not associated with a significant change in cartilage volume and joint space narrowing was not associated with a significant change in tibial bone area (all P>0.05).

CONCLUSIONS

Early medial compartment ROA is associated with substantial reductions in cartilage volume and increases in bone area. These large changes, when combined with similar measurement error for MRI and radiographs, suggest that MRI may be superior at detecting and hence understanding early osteoarthritis of the knee in humans.

Sex differences in knee cartilage volume in adults: role of body and bone size, age and physical activity

OBJECTIVE

To test the hypothesis that sex differences in knee cartilage volume may be mediated through body and bone size, age and/or physical activity.

METHODS

A cross-sectional convenience sample of 372 subjects (males 43%; mean age 45 yr, range 26-61) was studied. Articular cartilage volumes and bone size were determined at the patella, medial and lateral tibia by processing images acquired in the sagittal plane using T1-weighted fat saturation magnetic resonance imaging. Height, weight, physical activity (lower limb muscle strength, endurance fitness and questionnaire items) and radiographic osteoarthritis (ROA) were measured.

RESULTS

Gender explained 33-42% of the variation in knee cartilage volumes (all P < 0.001). Males had 33-42% higher cartilage volume than females at all sites. In the whole group, the magnitude of sex differences decreased to 8-18% after adjustment for body height, weight and bone size, but remained significant (all P < 0.05). Further adjustment for physical activity had no effect on the sex differences. The sex differences in cartilage volume were greater in those aged over 50 compared with those aged under 50 (P < 0.05 for age-sex interaction at all sites) and were independent of ROA.

CONCLUSIONS

Men have substantially higher knee cartilage volumes than women. These sex differences appear to be mediated in part by body and bone size but a significant amount remains unexplained. Furthermore, the differences become more marked over the age of 50 yr suggesting that both cartilage development and cartilage loss in later life contribute to sex differences in cartilage volume. Further longitudinal studies in large samples will be required to confirm these findings.

Drawing ability in autism: a window into the imagination

This study investigated imagination via drawing tasks, in 15 children with autism and 15 children with Asperger Syndrome, compared to verbal mental age matched normal children and children with moderate learning difficulties (MLD). Experiment 1 used the Draw an Impossible Man Task. While children with autism were impaired relative to the normal group, they were not impaired relative to the children with MLD. In order to probe for an imagination deficit, Experiment 2 employed a more challenging measure of imaginative drawing, a task involving mixing categories to produce drawings of real or unreal entities (e.g., drawing half-fish/half-mouse). This revealed an autism-specific deficit. Experiment 3 confirmed this was not due to difficulties in combining elements per se. Experiment 4 required subjects to transform a picture (e.g., a cloud into a swan) and again found an autism-specific deficit. Children with Asperger Syndrome were only impaired when required to make such transformations spontaneously.

Attitudes toward tuberculosis of final year medical students from Canada, India, and Uganda

BACKGROUND

Tuberculosis, although both preventable and treatable, continues to be the world's leading cause of death from an infectious agent.

PURPOSE

To extend the results of our previous study of knowledge and practices of final year medical students regarding tuberculosis at three medical schools from endemic and nonendemic areas and to describe their attitudes.

METHODS

Eight statements assessing attitudes, as part of a larger survey, were administered to final year medical students at McMaster University in Canada, Christian Medical College in India, and Makerere University in Uganda.

RESULTS

One hundred sixty surveys were returned with 155 completed attitude responses. The response rate was 68.4% (65 of 95) for McMaster University, 39.7% (23 of 58) for the Christian Medical College, and 78.3% (72 of 92) for Makerere University. Analysis showed that six of eight attitude items were slightly statistically different among the schools with minimal effect of curriculum time and patient exposure.

CONCLUSIONS

Despite quite varied exposure to tuberculosis, students from endemic and nonendemic areas responded similarly on statements addressing attitudes toward tuberculosis.

Cotton-based rotation systems on a sodic Vertosol under irrigation: effects on soil quality and profitability

An experiment was established in 1993 on a sodic Vertosol (Vertisol, Typic Haplustert) at Merah North, north–western New South Wales, to evaluate the sustainability of selected irrigated cotton (Gossypium hirsutum L.)–rotation crop sequences. Crop sequences were selected following discussions with local cotton growers. The indices used to evaluate sustainability included soil quality, microbiology, yield and profitability. This paper presents data on soil properties [soil organic C, structure as air–filled porosity of oven–dried soil, exchangeable Ca, Mg, K and Na, pH, electrical conductivity (EC1:5) and EC1:5/exchangeable Na in the 0–0.6 m depth], lint yield and profitability (as gross margins/ha and gross margins/ML of irrigation water). The 6 cropping systems sown after minimum tillage were: continuous cotton (R1), long–fallow cotton (R2), cotton–green manured faba bean (Vicia faba L.) (R3), cotton–dolichos (Lablab purpureus L.)–green manured faba bean in the first year followed by cotton–wheat (Triticum aestivum L.) (R4), cotton–dolichos (R5), cotton–fertilised dolichos (with P and K removed by cotton replaced as fertiliser) (R6). In 1996, air–filled porosity of oven–dried soil was highest with R4 at the surface but lowest with R1 in the 0.15–0.30 m depth. In subsequent years, air–filled porosity of oven–dried soil was higher with R2 and R4 in the deeper depths, although differences between cropping sequences were small. Air–filled porosity of oven–dried soil increased between 1996 and 1998 in all treatments, and was probably caused by the change from intensive to minimum tillage in 1993, irrigation with moderately saline water and application of gypsum resulting in an increase in EC1:5/exchangeable Na. In general, differences in soil properties such as soil organic C, exchangeable Ca, Mg, K and Na, pH, electrical conductivity (EC1:5) and EC1:5/exchangeable Na between cropping sequences were far less than those which occurred with time. The key changes were decreases in pH, exchangeable sodium percentage, exchangeable cations and organic C between 1994 and 1996, and increases in air–filled porosity of oven–dried soil, EC1:5 and EC1:5/exchangeable Na between 1996 and 1998. A decrease in air–filled porosity of oven–dried soil occurred between 1998 and 1999 as a consequence of preparing land and sowing cotton under very wet conditions. R1 had the highest cumulative gross margin/ha and R3 had the lowest. R2 had the highest cumulative gross margin/ML of irrigation water and R3 again the lowest. Among crop sequences, R2 and R4 gave the best returns with respect to both land and water resources.

Work correlates of back problems and activity restriction due to musculoskeletal disorders in the Canadian national population health survey (NPHS) 1994-5 data

OBJECTIVES

To describe the prevalence of musculoskeletal problems in the Canadian working population and to determine cross sectional associations between such problems and work factors, particularly job strain and physical demand variables.

METHODS

The Canadian 1994 national population health survey (NPHS) sampled 4230 working men and 4043 working women (ages 18-64) who answered an abbreviated version of the job content questionnaire. Workers were classified into four strain categories: high, passive, active, and low. Outcomes were restricted activity due to musculoskeletal disorders and the diagnosis of a back problem (both yes or no). Survey weights were incorporated to allow for different probabilities of selection. Logistic regression analyses were carried out separately for women and men, controlling for sociodemographic factors.

RESULTS

Prevalence of chronic back problems diagnosed by a health practitioner was 14.5% among men and 12.5% among women. Men had a 6.6% prevalence of restricted activity due to musculoskeletal disorders, whereas the corresponding figure for women was 5.3%. Women, but not men, in high strain jobs were more likely to report both back problems (odds ratio (OR) 1.60, 95% confidence interval (95% CI) 1.14 to 2.28) and restricted activity (OR 1.98, 95% CI 1.16 to 3.48) compared with those in low strain jobs. High physical exertion was an independent predictor of back problems in both sexes. For both men and women, low social support at work and high job insecurity were independent predictors of restricted activity due to musculoskeletal disorders. Conversely, chronic back problems contributed to explanation of high job strain among women (OR 1.76, 95% CI 1.30 to 2.39) and high physical exertion among men (OR 1.39, 95% CI 1.09 to 1.77), whereas restricted activity due to musculoskeletal disorders contributed to explanation of high job insecurity in both sexes.

CONCLUSIONS

Associations of interest between work stressors and musculoskeletal problems in this cross sectional study provide evidence for physical and psychosocial factors both affecting disability and being affected by disability in a working population.

Factors associated with delays in accessing HIV primary care in rural Arkansas

While debate continues at what stage of human immunodeficiency virus (HIV) disease to begin combination antiretroviral therapy, a number of clinical and public health benefits are linked to early entry into primary care soon after first testing HIV positive. However, HIV-infected patients continue to test late and delay entry into care. We used routinely collected demographic and clinical information to examine which factors are associated with delays in seeking care in a predominantly rural, economically poor area of Arkansas. The study population is 75% African American and male and 70% lack health insurance; nearly one fourth were referred from prison. At diagnosis, two thirds of the population had CD4 counts below 500 cells per microliter. Days from initial HIV diagnosis to entry into care declined from a median of 178 in 1994 to 24 in 1998. In 1998, 75% of the population entered into primary care within 2 months of diagnosis. However, CD4 counts at HIV diagnosis also declined in this period, from a median of 427 in 1995 to 208 cells per microliter in 1998. More recent year of diagnosis was associated with a shorter delay in seeking care; males, and individuals lacking health insurance took significantly longer to enter into care than females and those with insurance, respectively. Our univariate finding of extensive delays in seeking care in the prison population did not hold in the multivariate analysis. We found significant delays in time to initial HIV diagnosis, and further considerable delays in males and those lacking health insurance in the time taken to enter into primary care.

Fluorescent amplified fragment length polymorphism genotyping of Salmonella Enteritidis: a method suitable for rapid outbreak recognition

OBJECTIVE

To perform fluorescent amplified fragment length polymorphism (FAFLP) analysis on phage type (PT) reference strains of Salmonella enterica subsp. enterica serotype Enteritidis (S. Enteritidis), and S. Enteritidis PT 6 and 6a recent clinical isolates to determine its usefulness for primary characterization of clinical S. Enteritidis isolates, and then to determine whether FAFLP is suitable for rapid characterization of strains in an outbreak situation.

METHODS

Twenty-five PT reference strains of S. Enteritidis and 20 S. Enteritidis PT 6 and 6a clinical isolates were subjected to FAFLP analysis using the selective primer combinations Eco + 0-Mse + T and Eco + 0-Mse + TA.

RESULTS

FAFLP successfully separated each one of the 25 S. Enteritidis PT strains into distinct profiles, while macrorestriction and PFGE using XbaI identified 20 pulsed-field profiles. FAFLP also resolved cases and outbreaks due to S. Enteritidis PTs 6 and 6a.

CONCLUSIONS

The resolving power of FAFLP was higher than that of PFGE. FAFLP is a highly discriminatory genotyping method and, in conjunction with phage typing for primary subdivision of S. Enteritidis, provides a rapid and powerful tool for strain differentiation, both for outbreak investigation and for epidemiologic surveillance.

Measurement of comfort levels by means of electrical stapedial reflex in children

BACKGROUND

Patient success and satisfaction with a cochlear implant largely depend on the adequacy of the speech-processing program. The program is generated by means of behaviorally determined threshold and comfort levels for each electrode. As the minimum age for implantation continues to decrease, behavioral methods of measuring comfort levels have become more problematic, and so the need for objective ways to program speech processors has become more important.

OBJECTIVES

To evaluate the use of electrically evoked stapedial reflexes (ESRs) to measure comfort levels for children and compare these results with behavioral measurements, and to report the results of a questionnaire assessing the acceptability and general performance of program before and after adjustment of comfort levels measured with ESRs.

DESIGN AND SETTING

Before-after trial in the cochlear implant unit of a tertiary hospital.

PATIENTS AND METHODS

Programming with the ESR technique was successfully completed in 20 of a consecutive sample of 26 children undergoing programming of their cochlear implants.

OUTCOME MEASURES

Programming units as measured by the 2 programming techniques and numerical score of questionnaire.

RESULTS

Comfort levels with the ESR method were found to be consistently lower than those obtained with behavioral techniques. Children using programs set with ESRs wore their implants longer and had fewer episodes of discomfort to environmental sounds.

CONCLUSION

Comfort level estimation by means of ESRs is reliable and objective and hence a valuable programming tool in the pediatric population.

Knowledge and practices regarding tuberculosis: a survey of final-year medical students from Canada, India and Uganda

CONTEXT

Tuberculosis is one of the most common infectious diseases worldwide and is responsible for the largest number of deaths from a single infectious cause.

OBJECTIVE

The objective of this study was to compare the knowledge of and practices regarding tuberculosis in final-year medical students at schools from endemic and non-endemic areas.

SUBJECTS

Final-year medical students at McMaster University in Canada, the Christian Medical College in India, and Makerere University in Uganda.

METHODS

A questionnaire consisting of 20 multiple-choice questions assessing knowledge, practices, and exposure. A total knowledge score (maximum=13) and a total practice score (maximum=5) were created for each study site.

RESULTS

160 questionnaires were returned; the response rate was 68.4% (65/95) for McMaster University, 39.7% (23/58) for the Christian Medical College and 78.3% (72/92) for Makerere University. Students from Makerere University had the highest knowledge scores but differences were non-significant after adjustment for patient exposure and curriculum time (F(2,153)= 1.80, P=0.16). Differences in practice scores, however, remained significant after adjusting for curriculum time and patient exposure (F(2,153)=5.14, P=0.006). Knowledge score (F(1,156)=5.05, P=0.02), patient exposure (F(1,153)=9.11, P=0.003), and curriculum time and patient exposure (F(2,153)=5.14, P=0.006) were statistically significant positive predictors of the total practice score.

CONCLUSIONS

This study demonstrated significant differences in undergraduate exposure to tuberculosis, total knowledge, and practice competency at three medical schools in Canada, India, and Uganda. In general, the knowledge base and practice competency of all three graduating classes was adequate.

Cost-effectiveness of high-dose chemotherapy in first-line treatment of advanced multiple myeloma

The cost-effectiveness of high-dose chemotherapy in multiple myeloma was considered as part of a UK National Health Service Executive regional evidence-based appraisal process. The use of high-dose chemotherapy supported by autologous stem cell transplantation in patients under 65 years of age was shown to provide a marginal benefit of 0.7 life-years over conventional chemotherapy. This corresponded to an incremental cost 'per life-year gained' figure of approximately pound15 000, based upon initial treatment costs and trial-period data only. The use of high-dose chemotherapy in the first-line treatment of advanced multiple myeloma improves event-free and overall survival and appears to be a cost-effective treatment option.

Serine proteinase inhibitor 3 and murinoglobulin I are potent inhibitors of neuropsin in adult mouse brain

Extracellular serine protease neuropsin (NP) is expressed in the forebrain limbic area of adult brain and is implicated in synaptic plasticity. We screened for endogenous NP inhibitors with recombinant NP (r-NP) from extracts of the hippocampus and the cerebral cortex in adult mouse brain. Two SDS-stable complexes were detected, and after their purification, peptide sequences were determined by amino acid sequencing and mass spectrometry, revealing that target molecules were serine proteinase inhibitor-3 (SPI3) and murinoglobulin I (MUG I). The addition of the recombinant SPI3 to r-NP resulted in an SDS-stable complex, and the complex formation followed bimolecular kinetics with an association rate constant of 3.4 +/- 0.22 x 10(6) M(-1) s(-1), showing that SPI3 was a slow, tight binding inhibitor of NP. In situ hybridization histochemistry showed that SPI3 mRNA was expressed in pyramidal neurons in the hippocampal CA1-CA3 subfields, as was NP mRNA. Alternatively, the addition of purified plasma MUG I to r-NP resulted in an SDS-stable complex, and MUG I inhibited degradation of fibronectin by r-NP to 24% at a r-NP/MUG I molar ratio of 1:2. Immunofluorescence histochemistry showed that MUG I localized in the hippocampal neurons. These findings indicate that SPI3 and MUG I serve to inactivate NP and control the level of NP in adult brain, respectively.