Rickets in a child with prolonged acquired hypothyroidism secondary to Hashimoto's thyroiditis

Summary

Skeletal abnormalities with delayed bone age and decreased linear bone growth are commonly found in children with prolonged juvenile hypothyroidism. However, rachitic bone abnormalities have not been previously reported in children with acquired hypothyroidism. Here, we present a case of newly found rickets in an 8-year-old female with untreated acquired hypothyroidism secondary to Hashimoto's thyroiditis. Laboratory finding for abnormalities in calcium/phosphorus homeostasis and hormones that regulate skeletal health was normal. Her radiographic anomalies resolved with levothyroxine treatment alone, suggesting that hypothyroidism was the etiology of the rickets. To our knowledge, this is the first case report of rickets associated with long-standing severe acquired hypothyroidism that resolved exclusively with thyroid repletion.

Learning points

Thyroid hormone plays an important role in bone mineralization. Prolonged hypothyroidism can result in rachitic bone abnormalities noted on radiographs. Hypothyroidism should be considered in the evaluation of a child with rickets.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Interferon-gamma release assays for latent tuberculosis infection screening in Canadian federal correctional facilities

BACKGROUND: The correctional setting presents an opportunity for latent TB infection (LTBI) screening in an otherwise difficult to reach demographic. We evaluate factors associated with the fidelity of the tuberculin skin test (TST) and interferon-gamma release assay (IGRA), specifically the QuantiFERON^®-TB Gold In-Tube assay (QFT-GIT), explain factors associated with discordance, and report LTBI treatment outcomes.METHODS: We describe the association between demographic and clinical variables, and predictors of concordance with IGRA using univariate logistic regression in a population of TST-positive inmates. We report outcomes among those offered LTBI treatment.RESULTS: We observed concordance between TST and QFT-GIT in 90 of 306 (29.4%) inmates. Persons with TST+/QFT-GIT+ results were less likely to be male (OR 3.94, 95% CI 1.73-8.97) or have a BCG vaccination history (OR 0.34, 95% CI 0.12-0.95), and more likely to be foreign-born (P < 0.001). Of the 108 inmates offered LTBI treatment, 65 (60.1%) accepted and 51 (78.0%) completed. TST/QFT-GIT discordance has not been associated with disease during follow-up.CONCLUSION: Our findings suggest that TST/QFT-GIT discordance in Canadian federal inmates is common; however, low-risk of disease progression in those with discordance suggests that a shift towards IGRA-based screening is warranted and feasible.

Introduction and elimination of Bovine Viral Diarrhoea Virus in a commercial beef herd: a case study

Routine Bovine Viral Diarrhoea Virus (BVDV) monitoring of a commercial beef herd in southern New South Wales over a 10-year period provided an opportunity to assess the impact of the introduction of BVDV on that herd. BVDV antibody testing provided strong evidence that the herd was initially free of BVDV (2009-2011). Testing from 2012 suggested BVDV had been introduced into the herd and this was confirmed in 2015 with the identification of persistently infected (PI) animals. Having become established in the herd, the owners then set out to eliminate BVDV from the herd. Antigen testing aimed at identifying PI animals revealed BVDV was already absent from the herd. Subsequent antibody testing confirmed that the herd was now free from BVDV. Despite the incursion of BVDV in this herd, there was little measurable impact on reproductive performance (pregnancy rates), although suspected increased calf losses from birth to calf marking were reported. This is the first time such self-clearance has been documented as part of a longitudinal study under Australian conditions.

Knowledge, attitudes and management of bovine viral diarrhoea virus among eastern Australian cattle producers: results from a 2013 cross-sectional study

Bovine viral diarrhoea virus (BVDV) is an economically significant disease affecting the Australian cattle industry, with losses stemming from decreased production and reproductive performance and control costs. However, these losses can be difficult to appreciate, particularly in endemic regions. Overall, there is a variable but high herd-level seroprevalence in Australia. Despite a potentially high financial burden of the disease, the onus for control ultimately falls on producers and strategies employed will vary between regions. A cross-sectional study, using a postal survey, was conducted in 2013 to evaluate the BVDV knowledge, attitudes and management practices utilised by Australian cattle producers. A total of 192 producers participated in the study, and results indicate that knowledge and attitudes towards disease risk are variable and can be improved. Producer knowledge of how persistently infected (PI) animals are produced was higher than that of disease outcomes or transmission pathways. Implementation of biosecurity practices was limited, with approximately half of respondents employing quarantine procedures for introduced stock and only 2% indicating they would antigen test introduced stock for BVDV. Approximately a third (36%) of producers reported engaging in BVDV control, with the majority of these using vaccination strategies over deliberate exposure to a PI. Knowledge of and engagement with BVDV control was positively influenced by the producer relationships with veterinarians. Findings from this study suggest that building on education and delivering a consistent message among stakeholders would likely improve producer awareness and understanding in relation to BVDV and support decision making in BVDV management.

MON-070 Cross-Reactivity of Human Insulin and Insulin Analogues in Human Insulin Immunoassay Complicates Case of Medical Child Abuse

Background: Measurement of insulin levels with human insulin immunoassays is important in the investigation of hypoglycemia; however, cross-reactivity with insulin analogues complicates clinical assessment.

Clinical Case: A 2-month-old male presented with hypoglycemia. Initial tests were consistent with hyperinsulinemic hypoglycemia: low serum glucose (29 mg/dL, n 70 to 99), elevated insulin (90.1 mU/L, n 3.0 to 19.0), suppressed beta-hydroxybutyrate (0.16 mmol/L, n 0.02 to 0.27), and suppressed free fatty acids (0.27 mmol/L, n 0.50 to 1.60). C-peptide level resulted undetectable (<0.1 ng/mL, n 0.8 to 3.5) raising suspicion for exogenous insulin administration. History revealed an older brother with type 1 diabetes mellitus treated with insulins glargine and lispro. Only one caregiver was present in the hospital, who denied knowledge of exogenous insulin administration. Hypoglycemia persisted despite placement of a continuous 1:1 sitter, high-dose intravenous glucose (glucose infusion rate up to 21.6 mg/kg/min), and treatment with diazoxide. A repeat insulin measurement with the Roche Diagnostics assay specific for human insulin was performed on a critical sample and resulted elevated (13.9 uIU/L, n 2.6 to 24.9), suggestive of endogenous insulin. However, an extensive study of commercial human insulin immunoassays by Heurtault et al., including the Roche Diagnostics assay, has demonstrated cross-reactivity with insulin analogues and their metabolites [1]. Given persistent concern for exogenous insulin administration, the patient’s caregiver was asked to leave the bedside for an extended period of time which resulted in normoglycemia. Diazoxide and dextrose-containing IV fluids were discontinued. Patient maintained normoglycemia for the remainder of the admission and was discharged in the care of child protective services.

Conclusions: Cross-reactivity exists in human insulin immunoassays with insulin analogues and their metabolites complicating the determination of endogenous versus exogenous insulin as the cause of hyperinsulinemic hypoglycemia. It is important to know the cross-reactivity of the assay used if a diagnosis of surreptitious insulin administration is suspected. Separation of patient and possible perpetrators and involvement of child protective services is essential in suspected cases of exogenous insulin administration. Evaluation in cases where self-injection of insulin is suspected may be more difficult to decipher, and inclusion of c-peptide measurement at the time of hypoglycemia is critical.

Reference: [1] Heurtault B, Reix N, Meyer N, et al. Extensive study of human insulin immunoassays: promises and pitfalls for insulin analogue detection and quantification. Clin Chem Lab Med. 2014; 52:355-362.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries

BACKGROUND

The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients.

METHODS

We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step.

RESULTS

A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana.

CONCLUSIONS

Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

Postoperative Hypoparathyroidism After Total Thyroidectomy in Children

BACKGROUND

Postoperative hypocalcemia because of hypoparathyroidism is the most common complication of total thyroidectomy in children. We hypothesized that most children with postoperative hypocalcemia would be eucalcemic by 12 mo and sought to define risk factors for permanent hypoparathyroidism.

METHODS

We retrospectively reviewed children who underwent total thyroidectomy at a single children's hospital from 2012 to 2019. Patients with prior neck surgery were excluded. Indication for operation, final pathologic diagnosis, and postoperative serum calcium up to 12 mo were recorded. Permanent hypoparathyroidism was defined as supplemental calcium requirement beyond 1 y postoperatively.

RESULTS

Sixty-eight patients underwent total thyroidectomy. Graves' disease was the most common benign indication for surgery (38 patients). Twenty-six patients (38%) had cancer on final pathology. Central lymph node dissection (CLND) was performed in 12 cancer patients. Twenty-eight patients (41%) had postoperative hypocalcemia. Eight patients (12%) had hypocalcemia at 6 mo. Risk factors for hypoparathyroidism at 6 mo were a cancer diagnosis (odds ratio [OR] 6.7; P = 0.02), CLND (OR 12.6; P < 0.01), and parathyroid tissue in the surgical specimen on pathologic analysis (OR 19.5; P < 0.01). Only two patients (3%) developed permanent hypoparathyroidism, both of whom had thyroidectomy for cancer and underwent CLND.

CONCLUSIONS

Children with thyroid cancer are at high risk for postoperative hypocalcemia after total thyroidectomy. The risk is further increased by CLND, which should be performed selectively. A majority of patients with hypoparathyroidism at 6 mo postoperatively regain normal parathyroid function by 1 y. Permanent hypoparathyroidism in children after total thyroidectomy at a pediatric endocrine surgery center is rare.

Characterization of cytoplasmic viscosity of hundreds of single tumour cells based on micropipette aspiration

Cytoplasmic viscosity (μ c) is a key biomechanical parameter for evaluating the status of cellular cytoskeletons. Previous studies focused on white blood cells, but the data of cytoplasmic viscosity for tumour cells were missing. Tumour cells (H1299, A549 and drug-treated H1299 with compromised cytoskeletons) were aspirated continuously through a micropipette at a pressure of -10 or -5 kPa where aspiration lengths as a function of time were obtained and translated to cytoplasmic viscosity based on a theoretical Newtonian fluid model. Quartile coefficients of dispersion were quantified to evaluate the distributions of cytoplasmic viscosity within the same cell type while neural network-based pattern recognitions were used to classify different cell types based on cytoplasmic viscosity. The single-cell cytoplasmic viscosity with three quartiles and the quartile coefficient of dispersion were quantified as 16.7 Pa s, 42.1 Pa s, 110.3 Pa s and 74% for H1299 cells at -10 kPa (n cell = 652); 144.8 Pa s, 489.8 Pa s, 1390.7 Pa s, and 81% for A549 cells at -10 kPa (n cell = 785); 7.1 Pa s, 13.7 Pa s, 31.5 Pa s, and 63% for CD-treated H1299 cells at -10 kPa (n cell = 651); and 16.9 Pa s, 48.2 Pa s, 150.2 Pa s, and 80% for H1299 cells at -5 kPa (n cell = 600), respectively. Neural network-based pattern recognition produced successful classification rates of 76.7% for H1299 versus A549, 67.0% for H1299 versus drug-treated H1299 and 50.3% for H1299 at -5 and -10 kPa. Variations of cytoplasmic viscosity were observed within the same cell type and among different cell types, suggesting the potential role of cytoplasmic viscosity in cell status evaluation and cell type classification.

‘Bridging the Continuum' - Reporting Population-Level Trends Across the Continuum of Care: The Australian National Cancer Control Indicator (NCCI) Web Site

Background: High-quality data can assist the development of policy and cancer strategies, stimulate lines of research, and inform the provision of care leading to better cancer outcomes. In November 2017 Cancer Australia launched the National Cancer Control Indicators (NCCI) Web site ( https://ncci.canceraustralia.gov.au ), Australia's first interactive Web site of cancer-specific, national population-based data across the continuum of care. The NCCI Web site presents a set of indicators for monitoring national cancer trends and benchmarking internationally across seven key aspects of cancer control; prevention, screening, diagnosis, treatment, psychosocial care, research and outcomes. Aim: By presenting a set of indicators using seven domains from the cancer care continuum, the NCCI Web site presents the most current Australian national data for a range of cancer control indicators in an accessible and interactive format. The primary aim of the NCCI Web site (hosted as part of the Cancer Australia Web site) is to monitor and report the most recent population-level trends to drive improvements across the cancer control continuum in Australia, and to facilitate international benchmarking of Australia's cancer control efforts. Methods: National data level on 33 individual measures across the seven cancer continuum domains was accessed from both government and nongovernment data custodians. Where applicable and available for measures, data were disaggregated and presented by age, sex, indigenous status, remoteness area of residence and socioeconomic status. Review of the data analysis was undertaken by 46 external reviewers including data custodians and subject matter experts. Results: Example summary data from several indicators across the NCCI Web site, including demographic disaggregation by age, sex, remoteness area of residence and socioeconomic status (where available) will be provided. e.g., • Smoking prevalence has decreased substantially over the past 30 years, and smoking rates among both adolescents and adults in Australia are among the lowest in the world. • Cancer mortality rates have been falling steadily since 1995, across most cancer types. Australia has lower mortality rates from cancer when compared with most other similar developed countries, about 6% lower than the estimated global average in 2012. National population-level data showing incidence by stage at diagnosis for the top five most common cancers has also been reported on the Web site - making Australia one of the few countries in the world where these data are available. Conclusion: The NCCI Web site is a flagship data Web site providing, for the first time, an evolving high-level national data resource to monitor Australian population-level trends in cancer control across the continuum. As one of the very few cross-continuum cancer reporting resources in the world, this is a valuable resource for use by those within the international cancer control community.

Collection and Reporting of National Cancer Stage at Diagnosis Data in Australia (STaR Project)

Background: Stage at diagnosis is an important prognostic factor for cancer, providing contextual information for interpreting population health indicators such as mortality from cancer and cancer survival. Australian population-based cancer registries (PBCRs) routinely collect information on cancer incidence and mortality. The need for high quality, comprehensive national data on stage at diagnosis to supplement these data are widely recognized in Australia. The collection and dissemination of quality national stage data will enhance the: • ability to better monitor cancer outcomes, inform cancer control policy; • understand variations across different populations; and • identify where further research and targeted strategies may be required to improve cancer outcomes. Linking data on cancer stage at diagnosis with other administrative cancer data will also allow for a better understanding of the relationship between stage at diagnosis, treatments received, patterns of cancer recurrence, and survival outcomes. Aim: To strengthen national data capacity by collecting and reporting cancer stage at diagnosis for Cancer Australia's Stage, Treatment and Recurrence (STaR) project. Methods: Working with state and territory population-based cancer registries (PBCRs) and the Australian Pediatric Cancer Registry, Cancer Australia supported the development and testing of Business Rules for the collection of national cancer stage at diagnosis for: • The top 5 incident cancers based on the Tumor, Node, and Metastasis (TNM) staging system. These rules were endorsed by the Australasian Association of Cancer Registries (AACR) as a national standard in May 2016; and • Childhood cancers, with a separate set of Business Rules for 16 childhood cancer types based on the Toronto Pediatric Cancer Stage Guidelines. These rules were supported by the AACR as a national standard. Results: Using the AACR-endorsed Business Rules, comprehensive national cancer stage at diagnosis data for the top 5 incident cancers (for 2011) have been collected in Australia for the first time. Over 90% of incidence cases were able to be assigned a value for registry-derived (RD) stage at diagnosis for melanoma (97%), prostate (97%), and female breast (94%) cancers. Lower staging completeness was found for colorectal cancers (88%), and for lung cancers (72%). Business Rules for the collection of stage at diagnosis data for pediatric cancers have also been developed; 93% of sample cases diagnosed in the period 2006-2010 were able to be staged, ranging from 84% for nonrhabdomyosarcoma to 100% for hepatoblastoma. Conclusion: The Business Rules enabled the uniform collection of cancer stage at diagnosis data for the first time in Australia. The collection of these data will allow for the linkage of stage at diagnosis to other sources of information, including patterns of treatments applied, and enable reporting of survival and recurrence outcomes by stage.

Collection and Reporting of System-Wide Cancer Treatment Activity Data As Part of the Stage, Treatment and Recurrence (STaR) Project

Background: The need for high quality, comprehensive national data on the treatments applied to cancers is widely recognized within the Australian cancer control community. The analysis and reporting of cancer treatment data will greatly enhance our ability to better understand cancer care activity and outcomes - and in particular the treatments being applied across population groups. Aim: To collect and report national data on cancer treatments, as part of Cancer Australia's Stage, Treatment and Recurrence (STaR) project. The linking of this data with national data on stage at diagnosis, survival and recurrence, will help inform policy and practice and ultimately improve cancer outcomes. Methods: Cancer Australia developed a dataset of selected surgical procedures for the treatment of the top five incidence cancers (prostate, breast, colorectal, lung, and melanoma). A dataset of key selected radiotherapy, and systemic therapies for the treatment of all cancer types was also developed.

Data for reporting system-wide treatment activity were extracted from existing national health administrative datasets, including: the Pharmaceutical Benefits Scheme (PBS), the Medicare Benefits Schedule (MBS) and the National Hospital Morbidity Database (NHMD). The scope of the analysis was selected surgical procedures, radiotherapy procedures, or pharmaceutical agents administered with the general intent to change the outcome of the cancer and/or provide symptom relief/ palliative care. Results: The data reported provide a high-level national system-wide overview of cancer treatments applied, including: • More than 1 million radiotherapy services were provided for all cancers combined in Australia (as indicated by MBS reimbursement claims data) for the years 2013 to 2015 inclusive; • The number of people receiving systemic anticancer therapies in Australia for all cancers combined (as indicated by PBS reimbursement claims data) increased from 198,756 in 2012 to 247,939 in 2016; and • The number of hospital separations recorded in the NHMD (i.e., episodes of admitted patient care) for patients with a principal diagnosis of cancer undergoing surgery for the treatment of the top five high incidence cancers in Australia increased from 53,516 in 2010 to 57,651 in 2015. Conclusion: National cancer treatment data were successfully collected and reported. Australia is one of very few countries in the world to collect and report national system-wide treatment data with a specific focus on cancer. These data will be linked to cancer incidence, stage at diagnosis, survival and recurrence data to help inform for population-level reporting of cancer outcomes.

A Survey of "Felt" Versus "Real" Needs of Physical Therapists

Constantly emerging knowledge has made continual learning a necessity for health-related professionals. This research deter mined some educational needs of one professional group, physical therapists, to help plan necessary continuing education. A ques tionnaire was administered to 77 physical therapists to determine and compare felt needs (personal perceptions symptomatic of problems) and real needs (actual knowledge or skill weaknesses). A literature review prompted the hypothesis (null form) of no correlation between perceived felt needs and demonstrated real needs. Statistical testing (Pearson correlation) suggested a failure to reject the null hypothesis (.05 level). The differences existing between felt and real needs indicates the complexity of the needs assessment process and the limitations of a mailed questionnaire that only solicits perceptions of need in planning continuing edu cation programs.

Sprouty2 regulates endochondral bone formation by modulation of RTK and BMP signaling

Skeletal development is regulated by the coordinated activity of signaling molecules that are both produced locally by cartilage and bone cells and also circulate systemically. During embryonic development and postnatal bone remodeling, receptor tyrosine kinase (RTK) superfamily members play critical roles in the proliferation, survival, and differentiation of chondrocytes, osteoblasts, osteoclasts, and other bone cells. Recently, several molecules that regulate RTK signaling have been identified, including the four members of the Sprouty (Spry) family (Spry1-4). We report that Spry2 plays an important role in regulation of endochondral bone formation. Mice in which the Spry2 gene has been deleted have defective chondrogenesis and endochondral bone formation, with a postnatal decrease in skeletal size and trabecular bone mass. In these constitutive Spry2 mutants, both chondrocytes and osteoblasts undergo increased cell proliferation and impaired terminal differentiation. Tissue-specific Spry2 deletion by either osteoblast- (Col1-Cre) or chondrocyte- (Col2-Cre) specific drivers led to decreased relative bone mass, demonstrating the critical role of Spry2 in both cell types. Molecular analyses of signaling pathways in Spry2(-/-) mice revealed an unexpected upregulation of BMP signaling and decrease in RTK signaling. These results identify Spry2 as a critical regulator of endochondral bone formation that modulates signaling in both osteoblast and chondrocyte lineages.

A population-based study of tuberculosis case fatality in Canada: do Aboriginal peoples fare less well?

SETTING

The Province of Alberta, Canada.

OBJECTIVES

To explore trends in tuberculosis (TB) case fatality, compare TB case-fatality rates by population group and determine prognostic factors associated with TB-related death in Alberta from 1996 to 2012.

DESIGN

Retrospective cohort analysis.

RESULTS

During the study years, all-cause TB case fatality fell from 10.7% to 6.3%; the fall was attributable to a change in population structure, as there were more foreign-born and fewer older cases with time. A stable 2% of TB cases died without treatment. Compared to other population groups, Canadian-born Aboriginal case patients were more likely to die without treatment and to die younger. Of TB deaths that were TB-related, 68.9% occurred before or during the initial phase of treatment; of these, TB was a contributory cause of death in 77.5%, i.e., another medical condition was the primary cause of death. In multivariate analysis, age >64 years, aboriginality and miliary/disseminated or central nervous system disease were independent predictors for TB-related death.

CONCLUSION

Preventive therapy for those with latent tuberculous infection and a high-risk medical condition, early diagnosis of disease, and special support of older, Aboriginal or comorbid cases, once diagnosed, are necessary to further minimise TB case fatality in Alberta, Canada.

Y-STR genetic screening by high-resolution melting analysis

Currently, the widely used automated capillary electrophoresis-based short tandem repeat (STR) genotyping method for genetic screening in forensic practice is laborious, time-consuming, expensive, and technically challenging in some cases. Thus, new molecular-based strategies for conclusively identifying forensically relevant biological evidence are required. Here, we used high-resolution melting analysis (HRM) for Y-chromosome STR genotyping for forensic genetic screening. The reproducibility of the melting profile over dilution, sensitivity, discrimination power, and other factors was preliminarily studied in 10 Y-STR loci. The results showed that HRM-based approaches revealed more genotypes (compared to capillary electrophoresis), showed higher uniformity in replicate tests and diluted samples, and enabled successful detection of DNA at concentrations as low as 0.25 ng. For mixed samples, the melting curve profiles discriminated between mixed samples based on reference samples with high efficiency. The triplex Y-chromosome STR HRM assay was performed and provided a foundation for further studies such as a multiplex HRM assay. The HRM approach is a one-step application and the entire procedure can be completed within 2 h at a low cost. In conclusion, our findings demonstrate that the HRM-based Y-STR assay is a useful screening tool that can be used in forensic practice.

IGF-I Signaling in Osterix-Expressing Cells Regulates Secondary Ossification Center Formation, Growth Plate Maturation, and Metaphyseal Formation During Postnatal Bone Development

To investigate the role of IGF-I signaling in osterix (OSX)-expressing cells in the skeleton, we generated IGF-I receptor (IGF-IR) knockout mice ((OSX)IGF-IRKO) (floxed-IGF-IR mice × OSX promoter-driven GFP-labeled cre-recombinase [(OSX)GFPcre]), and monitored postnatal bone development. At day 2 after birth (P2), (OSX)GFP-cre was highly expressed in the osteoblasts in the bone surface of the metaphysis and in the prehypertrophic chondrocytes (PHCs) and inner layer of perichondral cells (IPCs). From P7, (OSX)GFP-cre was highly expressed in PHCs, IPCs, cartilage canals (CCs), and osteoblasts (OBs) in the epiphyseal secondary ossification center (SOC), but was only slightly expressed in the OBs in the metaphysis. Compared with the control mice, the IPC proliferation was decreased in the (OSX)IGF-IRKOs. In these mice, fewer IPCs invaded into the cartilage, resulting in delayed formation of the CC and SOC. Immunohistochemistry indicated a reduction of vessel number and lower expression of VEGF and ephrin B2 in the IPCs and SOC of (OSX)IGF-IRKOs. Quantitative real-time PCR revealed that the mRNA levels of the matrix degradation markers, MMP-9, 13 and 14, were decreased in the (OSX)IGF-IRKOs compared with the controls. The (OSX)IGF-IRKO also showed irregular morphology of the growth plate and less trabecular bone in the tibia and femur from P7 to 7 weeks, accompanied by decreased chondrocyte proliferation, altered chondrocyte differentiation, and decreased osteoblast differentiation. Our data indicate that during postnatal bone development, IGF-I signaling in OSX-expressing IPCs promotes IPC proliferation and cartilage matrix degradation and increases ephrin B2 production to stimulate vascular endothelial growth factor (VEGF) expression and vascularization. These processes are required for normal CC formation in the establishment of the SOC. Moreover, IGF-I signaling in the OSX-expressing PHC is required for growth plate maturation and osteoblast differentiation in the development of the metaphysis.

Feasibility and acceptability of web-based enhanced relapse prevention for bipolar disorder (ERPonline): trial protocol

BACKGROUND

Relapse prevention interventions for Bipolar Disorder are effective but implementation in routine clinical services is poor. Web-based approaches offer a way to offer easily accessible access to evidence based interventions at low cost, and have been shown to be effective for other mood disorders.

METHODS/DESIGN

This protocol describes the development and feasibility testing of the ERPonline web-based intervention using a single blind randomised controlled trial. Data will include the extent to which the site was used, detailed feedback from users about their experiences of the site, reported benefits and costs to mental health and wellbeing of users, and costs and savings to health services. We will gain an estimate of the likely effect size of ERPonline on a range of important outcomes including mood, functioning, quality of life and recovery. We will explore potential mechanisms of change, giving us a greater understanding of the underlying processes of change, and consequently how the site could be made more effective. We will be able to determine rates of recruitment and retention, and identify what factors could improve these rates.

DISCUSSION

The findings will be used to improve the site in accordance with user needs, and inform the design of a large scale evaluation of the clinical and cost effectiveness of ERPonline. They will further contribute to the growing evidence base for web-based interventions designed to support people with mental health problems.

Respirator-Fit Testing: Does It Ensure the Protection of Healthcare Workers Against Respirable Particles Carrying Pathogens?

Objective.

Respiratory protection programs, including fit testing of respirators, have been inconsistently implemented; evidence of their long-term efficacy is lacking. We undertook a study to determine the short- and long-term efficacy of training for fit testing of N95 respirators in both untrained and trained healthcare workers (HCWs).

Design.

Prospective observational cohort study.

Methods.

A group of at-risk, consenting HCWs not previously fit-tested for a respirator were provided with a standard fit-test protocol. Participants were evaluated after each of 3 phases, and 3 and 14 months afterward. A second group of previously fit-tested nurses was studied to assess the impact of regular respirator use on performance.

Results.

Of 43 untrained fit-tested HCWs followed for 14 months, 19 (44.2%) passed the initial fit test without having any specific instruction on respirator donning technique. After the initial test, subsequent instruction led to a pass for another 13 (30.2%) of the 43 HCWs, using their original respirators. The remainder required trying other types of respirators to acheive a proper fit. At 3 and 14 months' follow-up, failure rates of 53.5% (23 of 43 HCWs) and 34.9% (15 of 43 HCWs), respectively, were observed. Pass rates of 87.5%-100.0% were observed among regular users.

Conclusions.

Without any instruction, nearly 50% of the HCWs achieved an adequate facial seal with the most commonly used N95 respirator. Formal fit testing does not predict future adequacy of fit, unless frequent, routine use is made of the respirator. The utility of fit testing among infrequent users of N95 respirators is questionable.

Estimating surface NO2 and SO2 mixing ratios from fast-response total column observations and potential application to geostationary missions

Total-column nitrogen dioxide (NO₂) data collected by a ground-based sun-tracking spectrometer system (Pandora) and an photolytic-converter-based in-situ instrument collocated at NASA's Langley Research Center in Hampton, Virginia were analyzed to study the relationship between total-column and surface NO₂ measurements. The measurements span more than a year and cover all seasons. Surface mixing ratios are estimated via application of a planetary boundary-layer (PBL) height correction factor. This PBL correction factor effectively corrects for boundary-layer variability throughout the day, and accounts for up to ≈75 % of the variability between the NO₂ data sets. Previous studies have made monthly and seasonal comparisons of column/surface data, which has shown generally good agreement over these long average times. In the current analysis comparisons of column densities averaged over 90 s and 1 h are made. Applicability of this technique to sulfur dioxide (SO₂) is briefly explored. The SO₂ correlation is improved by excluding conditions where surface levels are considered background. The analysis is extended to data from the July 2011 DISCOVER-AQ mission over the greater Baltimore, MD area to examine the method's performance in more-polluted urban conditions where NO₂ concentrations are typically much higher.

Preventing tuberculosis in the foreign-born population of Canada: a mathematical modelling study

BACKGROUND

Foreign-born persons in Canada contribute 67% of all tuberculosis (TB) cases annually, but represent only 21% of the total population. Molecular epidemiological studies suggest that most foreign-born TB cases result from the reactivation of latent tuberculous infection (LTBI) acquired before immigration.

OBJECTIVE

To estimate the effect on incidence of a prevention strategy that would screen selected immigrants at arrival for LTBI and offer preventive treatment to those who test positive.

DESIGN

A deterministic model was developed to quantify the incidence of active TB in immigrants to Canada and validated with national immigration and TB case data.

RESULTS

Model simulations suggested that it would be optimal to screen and treat LTBI in new immigrants from countries of birth with an estimated TB incidence rate in excess of 50 per 100 000 person-years. If this strategy had been implemented in 1986, the national TB incidence rate would have fallen by 18.5%, from 5.4 to 4.4 cases per 100 000 population by 2002.

CONCLUSION

This study suggests that screening and treating LTBI in foreign-born persons from high TB incidence countries is the most effective strategy in terms of total persons screened and treated and percentage reduction in national incidence.

Sustained response to deep brain stimulation in LRRK2 parkinsonism with the Y1699C mutation

Although effective deep brain stimulation of the subthalamic nucleus (STN-DBS) is reported in G2019S leucine-rich repeat kinase 2 (LRRK2) parkinsonism, response to surgery in other LRRK2 mutations has not been previously reported. We present an affected individual from the Lincolnshire pedigree (Y1699C), on whom bilateral STN-DBS was performed to control severe motor fluctuations and dyskinesias. He showed a marked improvement in Unified Parkinson's Disease Rating Scale (UPDRS) Part III scores in the "on" and "off" states, sustained for more than three years. Bilateral STN-DBS in LRRK2-parkinsonism with the Y1699C mutation can be as effective as in sporadic PD.

Advanced bone age in a girl with Wiedemann-Steiner syndrome and an exonic deletion in KMT2A (MLL)

Recognition of the gene implicated in a Mendelian disorder subsequently leads to an expansion of potential phenotypes associated with mutations in that gene as patients with features beyond the core phenotype are identified by sequencing. Here, we present a young girl with developmental delay, short stature despite a markedly advanced bone age, hypertrichosis without elbow hair, renal anomalies, and dysmorphic facial features, found to have a heterozygous, de novo, intragenic deletion encompassing exons 2-10 of the KMT2A (MLL) gene detected by whole exome sequencing. Heterozygous mutations in this gene were recently demonstrated to cause Wiedemann-Steiner syndrome (OMIM 605130). Importantly, retrospective analysis of this patient's chromosomal microarray revealed decreased copy number of two probes corresponding to exons 2 and 9 of the KMT2A gene, though this result was not reported by the testing laboratory in keeping with standard protocols for reportable size cutoffs for array comparative genomic hybridization. This patient expands the clinical phenotype associated with mutations in KMT2A to include variable patterns of hypertrichosis and a significantly advanced bone age with premature eruption of the secondary dentition despite her growth retardation. This patient also represents the first report of Wiedemann-Steiner syndrome due to an exonic deletion, supporting haploinsufficiency as a causative mechanism. Our patient also illustrates the need for sensitive guidelines for the reporting of chromosomal microarray findings that are below traditional reporting size cutoffs, but that impact exons or other genomic regions of known function.

The cardioprotectant 3',4'-dihydroxyflavonol inhibits opening of the mitochondrial permeability transition pore after myocardial ischemia and reperfusion in rats

The study aimed to determine the effect of 3',4'-dihydroxyflavonol (DiOHF) on mitochondrial function, in particular opening of the mitochondrial permeability transition pore (mPTP), respiratory function and reactive oxygen species (ROS) production, in isolated cardiac mitochondria after coronary artery occlusion and reperfusion in vivo. Opening of the mPTP, oxygen consumption and ROS production (assessed by measurement of H2O2) was determined in mitochondria isolated from normal hearts or from the ischemic zone of rat hearts subjected to 30min coronary artery occlusion and 15min reperfusion. Treatment of sham rats with DiOHF (10mgkg(-1) iv) significantly increased the concentration of Ca(2+) required to stimulate mPTP opening. This was accompanied by increased state 3 oxygen consumption and decreased H2O2 release. Ischemia and reperfusion (IR) significantly decreased the concentration of Ca(2+) required to stimulate mPTP opening, decreased state 3 oxygen consumption and increased H2O2 release, when pyruvate plus malate was provided as a substrate. Treatment with DiOHF prevented IR-induced changes in mPTP opening, state 3 oxygen consumption and H2O2 release so that there was no difference compared to sham. In isolated cardiac mitochondria from normal rats DiOHF had no effect on mPTP opening or on state 3 respiration but caused a small increase in state 4 respiration and decreased the respiratory control ratio. DiOHF, administered during ischemia just before reperfusion, inhibits mPTP opening and preserves mitochondrial function through a mechanism likely to be independent of its antioxidant activity or any direct effect on the mPTP.

Transcriptome profiling of UPF3B/NMD-deficient lymphoblastoid cells from patients with various forms of intellectual disability

The nonsense-mediated mRNA decay (NMD) pathway was originally discovered by virtue of its ability to rapidly degrade aberrant mRNAs with premature termination codons. More recently, it was shown that NMD also directly regulates subsets of normal transcripts, suggesting that NMD has roles in normal biological processes. Indeed, several NMD factors have been shown to regulate neurological events (for example, neurogenesis and synaptic plasticity) in numerous vertebrate species. In man, mutations in the NMD factor gene UPF3B, which disrupts a branch of the NMD pathway, cause various forms of intellectual disability (ID). Using Epstein Barr virus-immortalized B cells, also known as lymphoblastoid cell lines (LCLs), from ID patients that have loss-of-function mutations in UPF3B, we investigated the genome-wide consequences of compromised NMD and the role of NMD in neuronal development and function. We found that ~5% of the human transcriptome is impacted in UPF3B patients. The UPF3B paralog, UPF3A, is stabilized in all UPF3B patients, and partially compensates for the loss of UPF3B function. Interestingly, UPF3A protein, but not mRNA, was stabilised in a quantitative manner that inversely correlated with the severity of patients' phenotype. This suggested that the ability to stabilize the UPF3A protein is a crucial modifier of the neurological symptoms due to loss of UPF3B. We also identified ARHGAP24, which encodes a GTPase-activating protein, as a canonical target of NMD, and we provide evidence that deregulation of this gene inhibits axon and dendrite outgrowth and branching. Our results demonstrate that the UPF3B-dependent NMD pathway is a major regulator of the transcriptome and that its targets have important roles in neuronal cells.

A population-based study of tuberculosis epidemiology and innovative service delivery in Canada

OBJECTIVE

To compare and interpret tuberculosis (TB) incidence rates in a Canadian population across two decennials (1989-1998 and 1999-2008) as a benchmark for World Health Organization targets and the long-term goal of TB elimination. The population under study was served by two urban clinics in the first decennial and two urban and one provincial clinic in the second.

METHODS

TB rates among Status Indians, Canadian-born 'others' and the foreign-born were estimated using provincial and national databases. Program performance was measured in on-reserve Status Indians in each decennial.

RESULTS

In each decennial, the incidence rate in Status Indians and the foreign-born was greater than that in the Canadian-born 'others'; respectively 27.7 and 33.0 times in Status Indians, and 8.0 and 20.9 times in the foreign-born. Between decennials, the rate fell by 56% in Status Indians, 58% in Canadian-born 'others', and 18% in the foreign-born. On-reserve Status Indians had higher rates than off-reserve Status Indians, and the three-clinic model out-performed the two-clinic model among those on-reserve. Rates in the foreign-born varied by World Bank region, and were highest among those from Africa and Asia.

CONCLUSION

Status Indians and the foreign-born are at increased risk of TB in Canada. Significant progress towards TB elimination has been made in Status Indians but not in the foreign-born.

Common functional polymorphisms of DISC1 and cortical maturation in typically developing children and adolescents

Disrupted-in-schizophrenia-1 (DISC1), contains two common non-synonymous single-nucleotide polymorphisms (SNPs)--Leu607Phe and Ser704Cys--that modulate (i) facets of DISC1 molecular functioning important for cortical development, (ii) fronto-temporal cortical anatomy in adults and (iii) risk for diverse psychiatric phenotypes that often emerge during childhood and adolescence, and are associated with altered fronto-temporal cortical development. It remains unknown, however, if Leu607Phe and Ser704Cys influence cortical maturation before adulthood, and whether each SNP shows unique or overlapping effects. Therefore, we related genotype at Leu607Phe and Ser704Cys to cortical thickness (CT) in 255 typically developing individuals aged 9-22 years on whom 598 magnetic resonance imaging brain scans had been acquired longitudinally. Rate of cortical thinning varied with DISC1 genotype. Specifically, the rate of cortical thinning was attenuated in Phe-carrier compared with Leu-homozygous groups (in bilateral superior frontal and left angular gyri) and accelerated in Ser-homozygous compared with Cys-carrier groups (in left anterior cingulate and temporal cortices). Both SNPs additively predicted fixed differences in right lateral temporal CT, which were maximal between Phe-carrier/Ser-homozygous (thinnest) vs Leu-homozygous/Cys-carrier (thickest) groups. Leu607Phe and Ser704Cys genotype interacted to predict the rate of cortical thinning in right orbitofrontal, middle temporal and superior parietal cortices, wherein a significantly reduced rate of CT loss was observed in Phe-carrier/Cys-carrier participants only. Our findings argue for further examination of Leu607Phe and Ser704Cys interactions at a molecular level, and suggest that these SNPs might operate (in concert with other genetic and environmental factors) to shape risk for diverse phenotypes by impacting on the early maturation of fronto-temporal cortices.

Piecing the puzzle together: foreign-born tuberculosis in an immigrant-receiving country

In major immigrant-receiving countries, annual foreign-born tuberculosis (TB) case counts and rates are relatively constant. Why this is so, and who might be a high-yield target for screening for latent TB infection, remain open questions. Foreign-born TB in Canada during 1986-2002 was retrospectively examined using national TB and immigration data as well as census data. Case counts and rates were analysed in relation to demographics, immigration period and time since arrival. Pre-1986 immigrants (n=3,860,853) and 1986-2002 immigrants (n=3,463,283) contributed 8,662 and 9,613 TB cases, respectively. Immigrants arriving ≤ 5 yrs ago and those arriving >10 yrs ago contributed almost equally to the annual foreign-born TB case count despite a 3.5-fold difference in in-country person-yrs. Remarkably stable and relatively low TB incidence was observed among immigrants >10 yrs post-arrival. Conversely, TB incidence within 5 yrs of arrival was dynamic, demonstrating a strong inverse association with time since arrival and higher sensitivity to changes in immigration level than shifts toward higher incidence source countries. Relative constancy in foreign-born TB incidence is explained by a complex convergence of several factors. Immigrants born in high-incidence countries who arrived ≤ 2 yrs ago and were aged 15-34 yrs upon arrival constitute high-yield targets for preventive therapy.

Impact of pharmacotherapy on the incidence of transurethral prostatectomy for benign prostatic hyperplasia and the implications for surgical training

Medical therapy has become first line treatment for Benign Prostatic Hypertrophy (BPH) and in many cases TURP may no longer be required. Proof and quantification of this evolution in practice has been somewhat elusive and provided the principle impetus for this study. This is a retrospective study of BPH management in Republic of Ireland from 1995 to 2008. National treatment databases were sourced for numbers undergoing TURP and pharmacotherapy prescribing data was obtained from individual pharmaceutical companies. A total of 28,240 TURP's were performed nationally between 1995 and 2008. TURP's performed annually, decreased by 1,494 (51%), alpha-blocker prescriptions increased from 8,710 to 302,159 units and the number of urology trainees increased by 10 (60%). Clear association between decreases in TURP's and increases in pharmacotherapy for BPH is demonstrated. Implications on training likely exist and will require proper evaluation in order to maintain future standards in this surgical practice.

Factors associated with treatment adherence in a randomised trial of latent tuberculosis infection treatment

SETTING

Randomised controlled trial of latent tuberculosis infection (LTBI) treatment in 10 clinics in Canada, Saudi Arabia and Brazil.

OBJECTIVE

To identify early predictors of LTBI treatment adherence, including pre-treatment characteristics.

DESIGN

Patients randomised to 4 months of rifampicin (RMP; n = 420) or 9 months of isoniazid (n = 427) were monitored for adherence using an electronic device. Outcomes were 1) treatment completion, defined as intake of >or=80% of the prescribed doses, and further categorised as completed within the allotted time or not; and 2) treatment regularity, measured by the time interval between doses. Relative risk (RR) and adjusted odds ratios (aOR) of patients' pre-treatment characteristics and adherence at first follow-up visit were calculated.

RESULTS

Completion of treatment was higher with RMP (aOR 4.3, 95%CI 2.7-6.8). Early predictors (first follow-up visit) of non-adherence were late first visit attendance (RR for completion in time 0.9, 95%CI 0.8-0.98), >20% of missed doses (RR 0.4, 95%CI 0.3-0.6) and greater variation of hours between doses (0.209 vs. 0.131, P < 0.001). Serious adverse events were not associated with irregularity of treatment.

CONCLUSION

The shorter RMP regimen was associated with better adherence. Patients with poor adherence could be identified at the first follow-up visit from their punctuality in follow-up, missed doses and variability of pill-taking.

Morphological adaptations of yak (Bos grunniens) tongue to the foraging environment of the Qinghai-Tibetan Plateau

Using light and scanning electron microscopy, the morphological adaptations of the yak (Bos grunniens) tongue to its foraging environment in the Qinghai-Tibetan Plateau were studied. The tongue of the yak was compared with that of cattle (Bos taurus). Compared with cattle, yak tongues are on average 4 cm shorter (P < 0.001), and yak consume forages using the labia oris, rather than by extending the tongue into the harsh environment. The lingual prominence of yak is greater (P < 0.001) and more developed than in cattle. The conical papillae on the prominence surface of yak are slightly larger (diameter: P = 0.068 and height: P = 0.761) and more numerous (P < 0.001) than in cattle. The lenticular papillae on the prominence surface of yak are larger (diameter: P = 0.002 and height: P = 0.115) and more numerous (P = 0.007) than in cattle. Such characteristics may improve the digestibility of forage by the grinding of food between the tongue and the upper palate. Filiform, conical, lenticular, fungiform, and vallate papillae were observed on the dorsal surface of the tongues studied; no foliate papillae were observed. The papillae were covered by keratinized epithelium, which was thicker (P < 0.001) in the yak than in cattle. It is suggested that the development of characteristic filiform papillae, and more numerous lingual gland ducts and mucus-secreting pores in the lenticular, fungiform and vallate papillae, fungiform papillae, probably having mechanical functions, are all morphological adaptations by yak to diets with greater fiber and DM content as provided by the plants within the Qinghai-Tibetan Plateau environment. On average, yak has 26 vallate papillae and cattle have 28. In the vallate papillae of the yak, the taste buds are arranged in a monolayer within the epithelium, whereas they are multilayered (2 to 4) in those papillae in cattle. The number of taste buds in each vallate papillae was less (P < 0.001) in the yak than in cattle. Therefore, the gustatory function of the yak was weaker than in cattle. Yaks graze throughout the year on diverse natural grasslands and have evolved morphological characteristics enabling them to consume a wide variety of plant species, thereby better adapting them to the typically harsh characteristics of their pastures.

Fluoroquinolone resistance in renal isolates of Mycobacterium tuberculosis

SETTING

Alberta, Canada, 1990-2003.

OBJECTIVE

Monotherapy of active tuberculosis (TB) promotes drug resistance. Given the common practice of empiric fluoroquinolone (FQ) therapy for urinary tract infections (UTI) and frequent delayed diagnosis of renal TB, we assessed urine Mycobacterium tuberculosis isolates for FQ resistance.

DESIGN

Retrospective study. Urine M. tuberculosis isolates underwent FQ susceptibility testing. Records were reviewed for evidence of FQ exposure and diagnostic delay.

RESULTS

Among 78 culture-positive renal TB patients between 1990 and 2003, initial isolates of M. tuberculosis were available from 74 (94.9%). Three (4.1%) were FQ-resistant. Previous FQ use was confirmed in nine cases (12.2%). FQ-exposed isolates were more likely than non-exposed isolates to be FQ-resistant (2/9, 22.2% vs. 1/65, 1.5%, P = 0.037). Among 41 cases (55.4%) with signs or symptoms of UTI, eight (19.5%) had previous FQ exposure, of which seven (87.5%) had delayed diagnosis. Only 15/33 (45.5%) UTI symptomatic cases without prior FQ exposure had delayed diagnosis (P = 0.050). In 2/8 (25%) UTI symptomatic cases with prior FQ exposure, the M. tuberculosis isolate was FQ-resistant.

CONCLUSION

FQ monotherapy of unsuspected renal TB may delay diagnosis and lead to FQ resistance.

Bronchial anthracofibrosis and tuberculosis in immigrants to Canada from the Indian subcontinent

BACKGROUND

Bronchial anthracofibrosis is a condition of proximal airway narrowing or obliteration and hyperpigmentation in persons with or without a history of occupational dust exposure. It is a bronchoscopic finding that is not uncommonly associated with pulmonary tuberculosis (PTB) in residents of South Korea, Iran and India. It is largely unrecognized in the Western world.

METHODS

We report the frequency of anthracofibrosis in foreign-born PTB patients who underwent bronchoscopy in two cities of Canada. We describe the composition of the pigment in the lungs of patients and speculate on the pathogenesis of anthracofibrosis-associated PTB.

RESULTS

Anthracofibrosis was present in 10/60 (16.7%) foreign-born patients who underwent bronchoscopy and had PTB between 2002 and 2006. Compared to patients from other Asian countries, patients from the Indian subcontinent were more likely to have anthracofibrosis (9/18, 50.0% vs. 1/26, 3.7%, P < 0.001). Carbonaceous particles, silica and silicates predominated in tissue specimens. Proximal airway narrowing appeared to be secondary to mixed dust- and smoke-related anthracofibrosis, PTB, or both.

CONCLUSIONS

Anthracofibrosis is not uncommon in immigrants to Canada from the Indian subcontinent with PTB. PTB may be a responsible or complicating condition in patients with anthracofibrosis.

Clinical spectrum of SIX3-associated mutations in holoprosencephaly: correlation between genotype, phenotype and function

BACKGROUND

Holoprosencephaly (HPE) is the most common structural malformation of the human forebrain. There are several important HPE mutational target genes, including the transcription factor SIX3, which encodes an early regulator of Shh, Wnt, Bmp and Nodal signalling expressed in the developing forebrain and eyes of all vertebrates.

OBJECTIVE

To characterise genetic and clinical findings in patients with SIX3 mutations.

METHODS

Patients with HPE and their family members were tested for mutations in HPE-associated genes and the genetic and clinical findings, including those for additional cases found in the literature, were analysed. The results were correlated with a mutation-specific functional assay in zebrafish.

RESULTS

In a cohort of patients (n = 800) with HPE, SIX3 mutations were found in 4.7% of probands and additional cases were found through testing of relatives. In total, 138 cases of HPE were identified, 59 of whom had not previously been clinically presented. Mutations in SIX3 result in more severe HPE than in other cases of non-chromosomal, non-syndromic HPE. An over-representation of severe HPE was found in patients whose mutations confer greater loss of function, as measured by the functional zebrafish assay. The gender ratio in this combined set of patients was 1.5:1 (F:M) and maternal inheritance was almost twice as common as paternal. About 14% of SIX3 mutations in probands occur de novo. There is a wide intrafamilial clinical range of features and classical penetrance is estimated to be at least 62%.

CONCLUSIONS

Our data suggest that SIX3 mutations result in relatively severe HPE and that there is a genotype-phenotype correlation, as shown by functional studies using animal models.

Use of the QuantiFERON-TB Gold test to confirm latent tuberculosis infection in a Canadian tuberculosis clinic

SETTING

Capital Health Tuberculosis (TB) Clinic, Edmonton, Alberta, Canada.

OBJECTIVE

To analyze the QuantiFERON-TB Gold In-Tube test (QFT) results after implementation as a routine test for tuberculin skin test (TST) positive patients.

DESIGN

From November 2004 until January 2007, patients who were TST-positive and were eligible for preventive treatment based on Canadian guidelines, were offered a QFT.

RESULTS

Of 1446 TST-positive patients, only 566 (39.6%) were QFT-positive. Categorized by reason for TST testing, 43.1% of 304 contacts, 32.8% of 348 employment screens and 24.2% of 298 post secondary school screens were QFT-positive. In contrast, 59.7% of 290 immigration screens were QFT-positive. A multivariate analysis found that QFT positivity was associated with older age, larger TST size, high-incidence TB region of birth, history of TB and chest X-ray findings suggestive of previous TB.

CONCLUSION

Implementation of the QFT as a secondary test for latent TB infection (LTBI) can significantly reduce the number of patients given LTBI treatment in a low-incidence country such as Canada.

A comparative study on urinary purine derivative excretion of yak (Bos grunniens), cattle (Bos taurus), and crossbred (Bos taurus x Bos grunniens) in the Qinghai-Tibetan plateau, China

Two experiments were conducted to determine the urinary purine derivative (PD) excretion rates and to analyze potential variations in PD excretions between yak, Tibetan indigenous cattle, and their crossbreds under similar ecological environment, and to develop prediction equations based on PD excretion for estimating rumen microbial protein supply. Three Tibetan castrated male yaks, and similar numbers of indigenous cattle and their crossbreds, were used in a fasting trial followed by a feeding trial, using three 3 x 3 Latin squares (1 for each breedtype), to measure responses of PD excretion to different feeding levels. The results showed that i) daily endogenous PD excretion for yak, indigenous cattle, and their crossbreds was 134, 163, and 138 micromol/kg of BW(0.75) (P = 0.38), respectively; and ii) crossbreds have greater PD excretion rate per unit digestible OM intake than indigenous cattle (P = 0.03). However, there were no significant differences between yaks and the crossbreds (P = 0.24) or between yaks and the indigenous cattle (P = 0.25). The proportion of allantoin to total PD in urine ranged from 0.83 to 0.88, with the crossbreds having greater values compared with the 2 parents (P = 0.03). Daily glomerular filtration rate, calculated using endogenous creatinine as an internal marker, for the above animals was 3.85, 4.23, and 3.61 L/kg of BW(0.75), respectively, in fasting trial (P = 0.59). The alpine animals may develop special regulating mechanisms in the kidney in terms of glomerular filtration rate and PD excretion, which would help the animals in adapting to the harsh environment of the Qinghai-Tibetan plateau.