CDC Grand Rounds: A Public Health Approach to Detect and Control Hypertension.

Hypertension is generally defined as systolic blood pressure ≥140 mmHg, or diastolic blood pressure ≥90 mmHg. A person who currently uses blood pressure-lowering medication is also defined as having hypertension. Hypertension is a leading risk factor for cardiovascular disease and stroke (1,2). Hypertension affects nearly one third of U.S. residents aged ≥18 years (approximately 75 million persons), and in approximately one half of adults with hypertension (nearly 35 million persons), it is uncontrolled (2). Among these 35 million U.S. residents with uncontrolled hypertension, 33% (11.5 million persons) are not aware of their hypertension, 20% (7 million persons) are aware of their hypertension, but are not being treated for it, and approximately 47% (16.1 million persons) are aware of their hypertension and being treated for it, but treatment (by medication and/or lifestyle modification) is not adequately controlling their blood pressure (Figure) (2).

Word production inconsistency of Singaporean-English-speaking adolescents with Down Syndrome.

BACKGROUND: The nature of speech disorders in individuals with Down Syndrome (DS) remains controversial despite various explanations put forth in the literature to account for the observed speech profiles. A high level of word production inconsistency in children with DS has led researchers to query whether the inconsistency continues into adolescence, and if the inconsistency stems from inconsistent phonological disorder (IPD) or childhood apraxia of speech (CAS). Of the studies that have been published, most suggest that the speech profile of individuals with DS is delayed, while a few recent studies suggest a combination of delayed and disordered patterns. However, no studies have explored the nature of word production inconsistency in this population, and the relationship between word production inconsistency, receptive vocabulary and severity of speech disorder. AIMS: To investigate in a pilot study the extent of word production inconsistency in adolescents with DS and to examine the correlations between word production inconsistency, measures of receptive vocabulary, severity of speech disorder and oromotor skills in adolescents with DS. METHODS & PROCEDURES: The participants were 32 native speakers of Singaporean-English adolescents, comprising 16 participants with DS and 16 typically developing (TD) participants. The participants completed a battery of standardized speech and language assessments, including The Diagnostic Evaluation of Articulation and Phonology (DEAP) assessment. Results from each test were correlated to determine relationships. Qualitative analyses were also carried out on all the data collected. OUTCOMES & RESULTS: In this study, seven out of 16 participants with DS scored above 40% on word production inconsistency, a diagnostic criterion for IPD. In addition, all participants with DS performed poorly on the oromotor assessment of DEAP. The overall speech profile observed did not exactly correspond with the cluster symptoms observed in children with IPD or CAS. CONCLUSIONS & IMPLICATIONS: Word production inconsistency is a noticeable feature in the speech of individuals with DS. In addition, the speech profiles of individuals with DS consist of atypical and unusual errors alongside developmental errors. Significant correlations were found between the measures investigated, suggesting that speech disorder in DS is multifactorial. The results from this study will help to improve differential diagnosis of speech disorders and individualized treatment plans in the population with DS.

The causal effect of vitamin D binding protein (DBP) levels on calcemic and cardiometabolic diseases: a Mendelian randomization study.

BACKGROUND: Observational studies have shown that vitamin D binding protein (DBP) levels, a key determinant of 25-hydroxy-vitamin D (25OHD) levels, and 25OHD levels themselves both associate with risk of disease. If 25OHD levels have a causal influence on disease, and DBP lies in this causal pathway, then DBP levels should likewise be causally associated with disease. We undertook a Mendelian randomization study to determine whether DBP levels have causal effects on common calcemic and cardiometabolic disease. METHODS AND FINDINGS: We measured DBP and 25OHD levels in 2,254 individuals, followed for up to 10 y, in the Canadian Multicentre Osteoporosis Study (CaMos). Using the single nucleotide polymorphism rs2282679 as an instrumental variable, we applied Mendelian randomization methods to determine the causal effect of DBP on calcemic (osteoporosis and hyperparathyroidism) and cardiometabolic diseases (hypertension, type 2 diabetes, coronary artery disease, and stroke) and related traits, first in CaMos and then in large-scale genome-wide association study consortia. The effect allele was associated with an age- and sex-adjusted decrease in DBP level of 27.4 mg/l (95% CI 24.7, 30.0; n = 2,254). DBP had a strong observational and causal association with 25OHD levels (p = 3.2 × 10(-19)). While DBP levels were observationally associated with calcium and body mass index (BMI), these associations were not supported by causal analyses. Despite well-powered sample sizes from consortia, there were no associations of rs2282679 with any other traits and diseases: fasting glucose (0.00 mmol/l [95% CI -0.01, 0.01]; p = 1.00; n = 46,186); fasting insulin (0.01 pmol/l [95% CI -0.00, 0.01,]; p = 0.22; n = 46,186); BMI (0.00 kg/m(2) [95% CI -0.01, 0.01]; p = 0.80; n = 127,587); bone mineral density (0.01 g/cm(2) [95% CI -0.01, 0.03]; p = 0.36; n = 32,961); mean arterial pressure (-0.06 mm Hg [95% CI -0.19, 0.07]); p = 0.36; n = 28,775); ischemic stroke (odds ratio [OR]  = 1.00 [95% CI 0.97, 1.04]; p = 0.92; n = 12,389/62,004 cases/controls); coronary artery disease (OR = 1.02 [95% CI 0.99, 1.05]; p = 0.31; n = 22,233/64,762); or type 2 diabetes (OR = 1.01 [95% CI 0.97, 1.05]; p = 0.76; n = 9,580/53,810). CONCLUSIONS: DBP has no demonstrable causal effect on any of the diseases or traits investigated here, except 25OHD levels. It remains to be determined whether 25OHD has a causal effect on these outcomes independent of DBP. Please see later in the article for the Editors' Summary.

CDC Grand Rounds: preventing hospital-associated venous thromboembolism.

Deep venous thrombosis (DVT) is a blood clot in a large vein, usually in the leg or pelvis. Sometimes a DVT detaches from the site of formation and becomes mobile in the blood stream. If the circulating clot moves through the heart to the lungs it can block an artery supplying blood to the lungs. This condition is called pulmonary embolism. The disease process that includes DVT and/or pulmonary embolism is called venous thromboembolism (VTE). Each year in the United States, an estimated 350,000-900,000 persons develop incident VTE, of whom approximately 100,000 die, mostly as sudden deaths, the cause of which often goes unrecognized. In addition, 30%-50% of persons with lower-extremity DVT develop postthrombotic syndrome (a long-term complication that causes swelling, pain, discoloration, and, in severe cases, ulcers in the affected limb). Finally, 10%-30% of persons who survive the first occurrence of VTE develop another VTE within 5 years.

Serum voriconazole level variability in patients with hematological malignancies receiving voriconazole therapy.

INTRODUCTION: Voriconazole plasma concentrations have been correlated with oral dosing in healthy subjects, but have been poorly characterized in ill patients with hematological malignancies receiving intensive chemotherapy. METHODS: The relationship between orally administered voriconazole, plasma concentrations and liver toxicity was examined in a cohort of 69 primarily acute leukemia patients undergoing intensive chemotherapy. RESULTS: Oral administration of voriconazole was associated with significant interpatient variability, with voriconazole steady-state concentrations ranging from 0 µg/mL to 16.6 µg/mL. Approximately 20% of patients achieved steady-state concentrations <1 µg/mL. When adjusted for weight, patients receiving higher voriconazole doses tended toward higher plasma concentrations; however, there was no significant relationship between the plasma concentration and genotype, age, sex or use of concomitant proton pump inhibitors. Voriconazole concentrations were correlated with higher serum alkaline phosphatase levels at day 6 to 8, and with higher bilirubin and aspartate aminotransferase levels at day 14 to 16, but not with other liver enzyme levels. CONCLUSION: In ill patients with acute leukemia and related disorders undergoing treatment with oral voriconazole, there is a poor correlation between the voriconazole dose and plasma concentrations, and many patients achieve levels that are considered to be subtherapeutic. The findings support the routine use of therapeutic drug monitoring in these patients.

INTRODUCTION: Les concentrations plasmatiques de voriconazole sont corrélées avec les doses orales chez les sujets en santé, mais sont mal caractérisées chez les patients malades atteints d'une hémopathie maligne sous chimiothérapie intensive. MÉTHODOLOGIE: Les chercheurs ont examiné le lien entre le voriconazole administré par voie orale et la toxicité hépatique dans une cohorte de 69 patients atteints surtout de leucémie aiguë sous chimiothérapie intensive. RÉSULTATS: L'administration de voriconazole par voie orale s'associait à une importante variabilité interpatient, les concentrations à l'état stable oscillant entre 0 µg/mL et 16,6 µg/mL. Environ 20 % des patients ont obtenu des concentrations à l'état stable de moins de 1 µg/mL. Après rajustement selon le poids, les patients qui receviaent des doses plus élevées de voriconazole avaient tendance à présenter des concentrations plasmatiques plus élevées. Cependant, on ne constatait aucun lien significatif entre la concentration plasmatique et le géno-type, l'âge, le sexe ou l'utilisation concomitante d'inhibiteurs de la pompe à protons. Les concentrations de voriconazole étaient corrélées avec des taux de phosphatase alcaline sérique plus élevés les jours 6 à 8 et à des taux de bilirubine et d'aspartate aminotransférase plus élevés les jours 14 à 16, mais pas à d'autres taux d'enzymes hépatiques. CONCLUSION: Chez les patients malades atteints d'une leucémie aiguë et de troubles connexes qui suivent un traitement au voriconazole par voie orale, la corrélation entre la dose de voriconazole et les concentrations plasmatiques est faible, et de nombreux patients obtiennent des taux considérés comme subthérapeutiques. Les observations soutiennent une pharmacovigilance systématique chez ces patients.

Developing DPYD Genotyping Method for Personalized Fluoropyrimidines Therapy.

BACKGROUND: Fluoropyrimidine drugs are widely used in chemotherapy to treat solid tumors. However, severe toxicity has been reported in 10% to 40% of patients. The DPYD gene encodes the rate-limiting enzyme dihydropyrimidine dehydrogenase responsible for fluoropyrimidine catabolism. The DPYD variants resulting in decreased or no enzyme activity are associated with increased risk of fluoropyrimidine toxicity. This study aims to develop a pharmacogenetic test for screening DPYD variants to guide fluoropyrimidine therapy. METHODS: A multiplex allele-specific polymerase chain reaction (AS-PCR) assay, followed by capillary electrophoresis, was developed to detect 5 common DPYD variants (c.557A > G, c.1129-5923C > G, c.1679T > G, c.1905 + 1G > A, and c.2846A > T). Deidentified population samples were used for screening positive controls and optimizing assay conditions. Proficiency testing samples with known genotypes were analyzed for test validation. All variants detected were confirmed by Sanger sequencing. RESULTS: From the deidentified population samples, 5 samples were heterozygous for c.557A > G, 2 samples were heterozygous for c.1129-5923C > G (HapB3), and 1 sample was heterozygous for c.2846A > T. The 20 proficiency samples matched with their assigned genotypes, including 13 wild-type samples, 3 samples heterozygous for c.1679T > G, 2 samples heterozygous for c.1905 + 1G > A, and 2 samples heterozygous for c.2846A > T. One of the 3 patient samples was heterozygous for c.1129-5923C > G (HapB3). All the variants detected by the multiplex AS-PCR assay were concordant with Sanger sequencing results. CONCLUSIONS: A robust multiplex AS-PCR assay was developed to rapidly detect 5 variants in the DPYD gene. It can be used for screening DPYD variants to identify patients with increased risk of toxicity when prescribed fluoropyrimidine therapy.

Urinary Vitamin D Binding Protein: A Marker of Kidney Tubular Dysfunction in Patients at Risk for Type 2 Diabetes.

Context: Recent studies have reported elevated urinary vitamin D binding protein (uVDBP) concentrations in patients with diabetic kidney disease, although the utility of uVDBP to predict deterioration of kidney function over time has not been examined. Objective: Our objective was to assess the association of uVDBP with longitudinal changes in kidney function. Methods: Adults at-risk for type 2 diabetes from the Prospective Metabolism and Islet Cell Evaluation (PROMISE) study had 3 assessments over 6 years (n = 727). Urinary albumin-to-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR) were used as measures of kidney function. Measurements of uVDBP were performed with enzyme-linked immunosorbent assay and normalized to urine creatinine (uVDBP:cr). Generalized estimating equations (GEEs) evaluated longitudinal associations of uVDBP and uVDBP:cr with measures of kidney function, adjusting for covariates. Results: Renal uVDBP loss increased with ACR severity at baseline. Individuals with normoalbuminuria, microalbuminuria, and macroalbuminuria had median log uVDBP:cr concentrations of 1.62 µg/mmol, 2.63 µg/mmol, and 2.48 µg/mmol, respectively, and ACR positively correlated with uVDBP concentrations (r = 0.37; P < .001). There was no significant association between uVDBP and eGFR at baseline. Adjusted longitudinal GEE models indicated that each SD increase both in baseline and longitudinal uVDBP:cr was significantly associated with higher ACR over 6 years (ß = 30.67 and ß = 32.91, respectively). Conversely, neither baseline nor longitudinal uVDBP:cr measures showed a significant association with changes in eGFR over time. These results suggest that loss of uVDBP:cr over time may be a useful marker for predicting renal tubular damage in individuals at risk for diabetes.

Common variants of the vitamin D binding protein gene and adverse health outcomes.

The vitamin D binding protein (DBP) is the major plasma carrier for vitamin D and its metabolites, but it is also an actin scavenger, and is the precursor to the immunomodulatory protein, Gc-MAF. Two missense variants of the DBP gene - rs7041 encoding Asp432Glu and rs4588 encoding Thr436Lys - change the amino acid sequence and alter the protein function. They are common enough to generate population-wide constitutive differences in vitamin D status, based on assay of the serum metabolite, 25-hydroxyvitamin D (25OHD). Whether these variants also influence the role of vitamin D in an immunologic milieu is not known. However, the issue is relevant, given the immunomodulatory effects of DBP and the role of protracted innate immune-related inflammation in response to tissue injury or repeated infection. Indeed, DBP and vitamin D may jointly or independently contribute to a variety of adverse health outcomes unrelated to classical notions of their function in bone and mineral metabolism. This review summarizes the reports to date of associations between DBP variants, and various chronic and infectious diseases. The available information leads us to conclude that DBP variants are a significant and common genetic factor in some common disorders, and therefore, are worthy of closer attention. In view of the heightened interest in vitamin D as a public health target, well-designed studies that look simultaneously at vitamin D and its carrier in relation to genotypes and adverse health outcome should be encouraged.

The Mashpee Wampanoag Tribe COVID-19 Pandemic Response: A Case Study.

During the COVID-19 pandemic, the Mashpee Wampanoag Tribe of southeastern Massachusetts requested US federal government assistance. The tribe collaborated successfully with many partners in response to the COVID-19 pandemic. In this case study, the authors describe the tribe's collaboration with a team from the Centers for Disease Control and Prevention who assisted with epidemiology, case investigation and contact tracing, infection prevention and control, community prevention measures, and vaccination. Collaborative efforts resulted in over 200 public service announcements and videos produced, 55 tribal staff trained, 222 people followed up for contact tracing, 80% of tribal members vaccinated, and 5 COVID-19 response plans written. Deployment response teams learned elements essential to partnering with a Native American tribe. This successful partnership during a rapidly evolving pandemic suggests the US federal government and tribal nations can work together effectively to build response capacity for future infectious disease threats.

Genetic variants in the vitamin D pathway and their association with vitamin D metabolite levels: Detailed studies of an inner-city pediatric population suggest a modest but significant effect in early childhood.

OBJECTIVES: In a large cohort of healthy infants and toddlers 6-36 months of age (n = 776), we have been exploring the potential role of genetic variation in predisposition to vitamin D insufficiency. The genes encoding the key cytochrome P450 hydroxylases (CYP2R1, CYP24A1, and CYP27B1) harbour recurrent mutations of uncertain effect. This study was undertaken to look for biochemically relevant associations of these variants with inter-individual differences in vitamin D metabolism in an at-risk pediatric population. METHODS: Genotyping for CYP2R1-CT (c.-1127 C>T, rs10741657), CYP24A1-AG (c.-686A>G, rs111622401), and CYP27B1-CA (c.-1261 C>A, rs10877012) mutations were performed using SNaPshot assay, followed by Sanger sequencing confirmation. Vitamin D metabolites and vitamin D binding protein (DBP) were measured by established methods. RESULTS: In a multivariate regression model, with corrections for co-variates, subjects with the homozygous CYP2R1-TT variant had significantly higher concentrations of 25(OH)D, free 25(OH)D, and 24,25(OH)2D levels. In subjects with the CYP24A1-AG mutation, concentrations of 25(OH)D were significantly higher. CONCLUSIONS: The CYP2R1-TT and CYP24A1-AG variants have measurable effects on the vitamin D pathway. It seems unlikely that they will be clinically relevant in isolation, but they may be members of the large pool of infrequent mutations contributing to different risks for the vitamin D deficiency phenotype.

Factors associated with delayed diagnosis of symptomatic adult COVID-19 cases presenting to primary care: a population-wide study during transition from Delta to Omicron BA.1 in Singapore.

Background: During pandemics, avoiding time delay in diagnosing infection is crucial. We evaluated factors associated with delayed diagnosis of symptomatic SARS-CoV-2 infection in a national cohort of adult Singaporeans, during which emergence of the more transmissible Omicron variant shifted pandemic management towards endemicity. Methods: Retrospective cross-sectional study amongst all adult Singaporeans diagnosed with symptomatic SARS-CoV-2 infection during the transition from Delta to Omicron BA.1 (September 2021-February 2022). SARS-CoV-2 testing was fully subsidised and compulsory for all symptomatic individuals presenting at primary care. Results and demographic information were extracted from national databases. Time to diagnosis was defined as days from symptom-onset to diagnosis (date of first positive SARS-CoV-2 test); dichotomising into no delay (≤24 h from symptom-onset) and delay >24 h. Multivariable logistic regression was utilised to assess factors associated with delay >24 h, and association of delay >24 h with progression to severe COVID-19. Findings: Of 149,063 Singaporean adults presenting with symptomatic SARS-CoV-2 infection, 75.9% (113,195/149,063) were diagnosed within 24 h of symptom-onset. On multivariable analysis, female gender, older age (>60 years), Chinese (vs. Malay) ethnicity, socioeconomic status (housing type), primary care characteristics, presentation during Omicron BA.1 (vs. Delta), symptom-onset on Friday/Saturday (vs. Monday), and not having completed a primary vaccination series were independently associated with higher odds of delay >24 h. Delay >24 h was independently associated with severe COVID-19 (adjusted odds-ratio, aOR = 1.45, 95% CI = 1.27-1.65, p < 0.001). Interpretation: At-risk populations (unvaccinated, age >60 years) had higher odds of delay in diagnosis. Delay >24 h in diagnosis was independently associated with severe COVID-19. Funding: This study was not grant-funded.

Real-world effectiveness of nirmatrelvir/ritonavir against COVID-19 hospitalizations and severe COVID-19 in community-dwelling elderly Singaporeans during Omicron BA.2, BA.4/5, and XBB transmission.

OBJECTIVES: Real-world data on continued effectiveness of nirmatrelvir/ritonavir against hospitalization and severe COVID-19 in the context of widespread booster mRNA vaccine uptake and more immune-evasive Omicron sub-variants are lacking. We conducted a retrospective cohort study in adult Singaporeans aged ≥60 years presenting to primary care with SARS-CoV-2 infection, during waves of Omicron BA.2/4/5/XBB transmission. METHODS: Binary logistic regression was used to estimate the effect of treatment (receiving nirmatrelvir/ritonavir) on outcomes (hospitalization, severe COVID-19). Additional sensitivity analyses, including inverse-probability-of-treatment-weighting-adjusted analysis and adjustment using overlap weights, were performed to account for observed differences in baseline characteristics among treated/untreated cohorts. RESULTS: We included 3959 nirmatrelvir/ritonavir recipients and 139 379 untreated controls. Almost 95% received ≥3 doses of mRNA vaccines; 5.4% had preceding infection. Overall 26.5% of infections occurred during the Omicron XBB period and 1.7% were hospitalized. On multivariable logistic regression, receipt of nirmatrelvir/ritonavir was independently associated with lower odds of hospitalization (adjusted odds ratio [aOR] = 0.65, 95% CI = 0.50-0.85). Consistent estimates were obtained after inverse-probability-of-treatment-weighting adjustment (aOR for hospitalization = 0.60, 95% CI = 0.48-0.75) and adjustment using overlap weights (aOR for hospitalization = 0.64, 95% CI = 0.51-0.79). Although receipt of nirmatrelvir/ritonavir was associated with lower odds of severe COVID-19, it was not statistically significant. DISCUSSION: Outpatient usage of nirmatrelvir/ritonavir was independently associated with reduced odds of hospitalization amongst boosted older community-dwelling Singaporeans during successive waves of Omicron transmission, including Omicron XBB; however, it did not significantly reduce the already low risk of severe COVID-19 in a highly vaccinated population.

Novel Glial Cells Missing-2 (GCM2) variants in parathyroid disorders.

OBJECTIVE: The aim of this study was to analyze variants of the gene glial cells missing-2 (GCM2), encoding a parathyroid cell-specific transcription factor, in familial hypoparathyroidism and in familial isolated hyperparathyroidism (FIHP) without and with parathyroid carcinoma. DESIGN: We characterized 2 families with hypoparathyroidism and 19 with FIHP in which we examined the mechanism of action of GCM2 variants. METHODS: Leukocyte DNA of hypoparathyroid individuals was Sanger sequenced for CASR, PTH, GNA11 and GCM2 mutations. DNA of hyperparathyroid individuals underwent MEN1, CDKN1B, CDC73, CASR, RET and GCM2 sequencing. The actions of identified GCM2 variants were evaluated by in vitro functional analyses. RESULTS: A novel homozygous p.R67C GCM2 mutation which failed to stimulate transcriptional activity in a luciferase assay was identified in affected members of two hypoparathyroid families. Oligonucleotide pull-down assay and in silico structural modeling indicated that this mutant had lost the ability to bind the consensus GCM recognition sequence of DNA. Two novel (p.I383M and p.T386S) and one previously reported (p.Y394S) heterozygous GCM2 variants that lie within a C-terminal conserved inhibitory domain were identified in three affected individuals of the hyperparathyroid families. One family member, heterozygous for p.I138M, had parathyroid carcinoma (PC), and a heterozygous p.V382M variant was found in another patient affected by sporadic PC. These variants exerted significantly enhanced in vitrotranscriptional activity, including increased stimulation of the PTH promoter. CONCLUSIONS: We provide evidence that two novel GCM2 R67C inactivating mutations with an inability to bind DNA are causative of hypoparathyroidism. Additionally, we provide evidence that two novel GCM2 variants increased transactivation of the PTH promoter in vitro and are associated with FIHP. Furthermore, our studies suggest that activating GCM2 variants may contribute to facilitating more aggressive parathyroid disease.

Mild infantile hypercalcemia: diagnostic tests and outcomes.

OBJECTIVE: To assess outcome in a cohort of patients with infantile hypercalcemia followed over 3 years. STUDY DESIGN: Patients (n = 32) presenting to the calcium clinic between July 2002 and September 2008 were studied. In addition to tests of calcium phosphate metabolism, serum insulin-like growth factor-1, calcitonin, urine citrate, and calcium-sensing receptor gene analysis were obtained. RESULTS: Mean age at presentation was 6.0 ± 6.3 months. Mean calcium level was 11.4 ± 0.7 mg/dL (2.84 ± 0.17 mmol/L). A recognized cause was found in 14% and a probable cause in 14% of the cohort. Those with nephrocalcinosis (n = 11) had significantly lower mean weight SDS and higher mean calcium levels. The biochemical profile of those in whom no cause could be determined included nonsuppressed parathyroid hormone with either normal or increased 1,25(OH)(2)D. Hypercalcemia resolved in 20 patients. However, in approximately a third, there was persistence in hypercalcemia, hypercalciuria, or nephrocalcinosis. CONCLUSIONS: The addition of 1,25(OH)(2)D and calcium-sensing receptor mutation analysis to a panel of investigations may improve diagnostic yield. Clinical outcome is overall good, however, one-third need ongoing follow-up.

Multicenter study to determine disk diffusion and broth microdilution criteria for prediction of high- and low-level mupirocin resistance in Staphylococcus aureus.

Mupirocin susceptibility testing of Staphylococcus aureus has become more important as mupirocin is used more widely to suppress or eliminate S. aureus colonization and prevent subsequent health care- and community-associated infections. The present multicenter study evaluated two susceptibility testing screening methods to detect mupirocin high-level resistance (HLR), broth microdilution (BMD) MICs of >or=512 microg/ml, and a 6-mm zone diameter for a disk diffusion (DD) test with a 200-microg disk. Initial testing indicated that with Clinical and Laboratory Standards Institute methods for BMD and DD testing, the optimal conditions for the detection of mupirocin HLR were 24 h of incubation and reading of the DD zone diameters with transmitted light. Using the presence or absence of mupA as the "gold standard" for HLR, the sensitivity and specificity of a single-well 256 microg/ml BMD test were 97 and 99%, respectively, and those for the 200-microg disk test were 98 and 99%, respectively. Testing with two disks, 200 microg and 5 microg, was evaluated for its ability to distinguish HLR isolates (MICs >or= 512 microg/ml), low-level-resistant (LLR) isolates (MICs = 8 to 256 microg/ml), and susceptible isolates (MICs

External quality assessment of HLA-B*5701 reporting: an international multicentre survey.

OBJECTIVES: HLA-B*5701 strongly predicts abacavir hypersensitivity (HSR), but implementation of effective routine screening into clinical practice requires testing be practical and accurate. We tested the proficiency of HLA-B*5701 typing among laboratories using sequence-specific primer PCR. DESIGN AND METHODS: DNA panels (1 and 2) were distributed to seven laboratories (A to G) for blinded typing of the HLA-B*5701 allele. Panel 1 (n = 10 samples; n = 7 laboratories) included 3 positives and other closely related B17 subtypes (B*5702, B*5703, B*5704 and B*5801). Panel 2 (n = 96 samples; n = 4 laboratories) included 36 positives among a broad spectrum of other B alleles. Two laboratories (A and B) also submitted 96 routine samples, typed by the same methodology, to the reference centre for additional analysis by sequence-based typing. RESULTS: All laboratories correctly typed panel 1 for HLA-B*5701 carriage. Laboratories A, B and C identified HLA-B*5701 alleles in panel 2 with 100% sensitivity and 100% specificity. Laboratory D reported one false negative, reportedly due to a sampling error. The results obtained for routine samples typed by laboratories A and B and those generated by the reference laboratory using sequencing were fully concordant. CONCLUSIONS: Detection of HLA-B*5701 alleles among laboratories was 100% specific and 99.4% sensitive, indicating that participating HIV testing laboratories were currently offering effective primary screening to identify individuals at high risk of abacavir HSR. Accurate reporting of HLA-B*5701 status is critical for the safe administration of this drug and participation in quality assurance programmes by all sites who report HLA-B*5701 status should be promoted.

Genetic variation at the calcium-sensing receptor (CASR) locus: implications for clinical molecular diagnostics.

OBJECTIVES: The calcium-sensing receptor (CASR) is critical for maintenance of blood calcium in a narrow physiologic range. Naturally occurring mutations in the calcium-sensing receptor gene (CASR) cause hypocalcaemia or hypercalcaemia, and molecular diagnosis of these mutations is clinically important. Knowledge of SNP frequency and haplotype structure is essential in understanding molecular test results. DESIGN AND METHODS: Genotyping and haplotype analysis of 26 CASR SNPs (and a tetranucleotide insertion/deletion polymorphism) in control cohorts of Caucasian, Asian and African-American origin (n=1136, 88 and 104 chromosomes, respectively). RESULTS: The three SNPs in exon 7 (A986S, R990G, Q1011E) are the only common exonic variants in our cohorts, and synonymous exonic SNPs are uncommon. Linkage disequilibrium analysis of the Caucasian cohort (Haploview) showed that the CASR locus is divided into three haplotype blocks, coincident with 5' regulatory, coding, and 3' regulatory domains. CONCLUSIONS: These analyses provide an important framework for appropriate interpretation of CASR mutation screening now offered by a number of laboratories for the diagnosis of calcium disorders. They will assist in the study of CASR polymorphisms as predictors of complex disease states.

Frequency of CYP2C9 polymorphisms affecting warfarin metabolism in a large anticoagulant clinic cohort.

OBJECTIVES: To assess allele frequency and genotype distribution of CYP2C9 polymorphisms in patients (n = 189) attending an anticoagulant clinic in comparison to control patients (n = 177) and also to assess if the patients with variant genotypes require lower doses of warfarin. METHODS: Genotyping of the common CYP2C9 variants *2 and *3 was carried out by multiplexed PCR-RFLP while the *5 and *6 allele variants were genotyped by singleton PCR-RFLP. DNA sequencing was used to confirm genotype in all specimens with *3, *4 and *6 alleles. RESULTS: CYP2C9 allele frequencies in patients were 0.81 for *1, 0.11 for *2 and 0.08 for *3, compared to 0.88, 0.08 and 0.04, respectively, in controls. Patients with *1/*3 and *X/*X (where *X is *2 or *3) genotypes required 32 to 67% less warfarin in comparison to patients with the normal *1/*1 genotype. Other alleles were observed in less than 1% of subjects. CONCLUSIONS: Allele frequencies and genotypes for CYP2C9*2 and *3 variants in patients on warfarin are not statistically different from controls whether or not they are stratified for ethnicity. Less common genotypes (*4, *5, *6) do not contribute significantly to warfarin sensitivity among patients attending a routine anticoagulation clinic. CYP2C9 genotype predicts warfarin dosage even in an uncontrolled, retrospective survey of unselected patients on warfarin therapy.

Predictors of suicide ideation and depression in Hong Kong adolescents: perceptions of academic and family climates.

The unique dimensions of perceptions of school and family contributing to depression and suicide ideation in Hong Kong adolescents were examined in two studies. In Study 1, among 327 Hong Kong Chinese female students ages 13-18, 47% reported some suicide ideation. Suicide ideation was significantly associated with depression, test anxiety, academic self-concept, and adolescents' perceived parental dissatisfaction with academic performance. The correlation between test anxiety and depression was especially high (r = .51). Study 2 examined how three different aspects of perceived family relationship were associated with depression and suicide ideation. Among 371 Hong Kong Chinese adolescents ages 14-20, 52.6% reported suicide ideation. Low levels of family cohesion and support and high levels of parent-adolescent conflict were positively related to depression and suicide ideation in both genders. Across both studies, depression mediated associations between academic- and family-related variables and suicide ideation. Findings underscore the importance of both academic and family climate in understanding depression and suicide ideation among Chinese adolescents.