Characterization of 107 genomic DNA reference materials for CYP2D6, CYP2C19, CYP2C9, VKORC1, and UGT1A1: a GeT-RM and Association for Molecular Pathology collaborative project

Pharmacogenetic testing is becoming more common; however, very few quality control and other reference materials that cover alleles commonly included in such assays are currently available. To address these needs, the Centers for Disease Control and Prevention's Genetic Testing Reference Material Coordination Program, in collaboration with members of the pharmacogenetic testing community and the Coriell Cell Repositories, have characterized a panel of 107 genomic DNA reference materials for five loci (CYP2D6, CYP2C19, CYP2C9, VKORC1, and UGT1A1) that are commonly included in pharmacogenetic testing panels and proficiency testing surveys. Genomic DNA from publicly available cell lines was sent to volunteer laboratories for genotyping. Each sample was tested in three to six laboratories using a variety of commercially available or laboratory-developed platforms. The results were consistent among laboratories, with differences in allele assignments largely related to the manufacturer's assay design and variable nomenclature, especially for CYP2D6. The alleles included in the assay platforms varied, but most were identified in the set of 107 DNA samples. Nine additional pharmacogenetic loci (CYP4F2, EPHX1, ABCB1, HLAB, KIF6, CYP3A4, CYP3A5, TPMT, and DPD) were also tested. These samples are publicly available from Coriell and will be useful for quality assurance, proficiency testing, test development, and research.     

Latent Tuberculosis Infection: Treatment Initiation and Completion Rates in Persons Seeking Immigration and Health Care Workers

BackgroundWe assessed the factors associated with initiation and completion rates of latent tuberculosis (TB) infection treatment in persons evaluated at an infectious diseases outpatient clinic in central Massachusetts. The Centers for Disease Control and Prevention (CDC) estimates that there may be up to 14 million persons in the United States with a latent TB infection. The risk of developing active TB in these persons can range from 5% to 15%. Hence, treatment of latent TB infection is an important aspect of any plan attempting to eradicate TB from the United States.MethodsWe performed a retrospective chart review of patients referred to our outpatient infectious diseases clinic from December 2006 to October 2010.ResultsOverall treatment initiation and completion rates were 76% and 68%, respectively, in our cohort. Two factors that were statistically significant for higher rates of treatment completion were 4 or more follow-up visits during the course of treatment (P < 0.001) and persons seeking immigration (PSI) to the United States (P < 0.02). Rate of treatment refusal was higher in health care workers as compared to workers not in health care (35% vs 13%, P = 0.004, 95% confidence interval [CI]: 1.38-4.91).ConclusionOur study reveals findings not previously reported in the US literature. We noted a high rate of treatment completion in persons seeking immigration to the United States. The second unique observation is the higher treatment completion rates in persons with 4 or more follow-up visits. We suggest that an emphasis on at least 4 follow-up visits can be an intervention that could improve the overall rates of treatment completion.     

Incidence and risk factors for surgical infection after total knee replacement

Surgical site infection (SSI) after total knee replacement (TKR) is a devastating complication. We performed a retrospective study of all consecutive TKRs performed during a 2-y period. Surgical site infection (SSI) was defined by standard criteria. All patients were examined 1 y following surgery. Of 180 patients undergoing TKR, 10 (5.6%) developed a superficial (3, 1.7%) or deep (7, 3.9%) SSI. Two independent risk factors for SSI were detected: left knees became infected more often (9/ 92, 9.8%) than right knees (1/88, 1.1%) (Relative Risk 6.7 +/- 95% CI 1.7-26.8); and 7/72 (9.7%) patients receiving a type-1 prosthesis developed infection versus 3/104 (3.1%) receiving a type-2 prosthesis (RR 4.7, 95% CI 1.18-18.4). Investigation of the operating room revealed 3 problems: there was significant traffic through the door on the left of the patient; a nonstandard horizontal-flow air conditioner had been installed above that door; a tool-washing sink was in use on the other side of that door. Infection control guidelines were rehearsed: the sink was removed, the air conditioner was disconnected, and the door was locked. In a prospective survey performed 2 y later only 1/45 patients (2.2%) undergoing TKR developed a superficial SSI (p = 0.5). Correction of independent risk factors for infection following TKR led to a decrease in SSI rate.     

Infection with a proposed new subspecies of Babesia canis, Babesia canis subsp. presentii, in domestic cats

Parasitemia with a large Babesia species was identified in two domestic cats from Israel. One cat, also coinfected with feline immunodeficiency virus and "Candidatus Mycoplasma haemominutum," had profound icterus and anemia which resolved after therapy, whereas a second cat was an asymptomatic carrier. Amplification and sequencing of the 18S rRNA gene, followed by phylogenetic analyses, indicated that infection was caused by Babesia canis. However, the sequences of the internal transcribed and 5.8S rRNA regions of the ribosomal operon used for subspeciation of B. canis were markedly different from the recognized subspecies of B. canis, which include B. canis vogeli, B. canis canis, and B. canis rossi. Based on phylogenetic comparisons of the 18S rRNA gene, 5.8S, and internal transcribed spacer sequences of the isolates from the cats and on the smaller sizes of the merozoite and trophozoite stages of this parasite, which distinguish it from the subspecies of B. canis present in dogs, we propose to identify the novel feline genotype of B. canis described in the present study as a new subspecies, B. canis subsp. presentii.     

Remediating deficits of switching attention in patients with acquired brain injury

Objective : This study was designed to evaluate the remediating effects of two types of aid on a test of switching attention administered to patients with acquired brain injury (ABI). Based on the separation of cognitive functions suggested by a neural network model, it was hypothesized that external inhibition of obsolete rules, and increased salience of stimuli, would differentially improve the WCST performance of participants with ABI.

Design and method : The Wisconsin Card Sorting Test (WCST) performance of 24 patients with ABI assigned to three treatment groups (no treatment, external inhibition, increased stimulus salience) was compared to normal controls.

Main outcomes : External inhibition of learned rules reduced perseverative errors, while increased stimuli salience reduced random errors, committed by patients with ABI.

Conclusions : The pattern of results supports the separation of functions in switching attention suggested by a neural network model, and establishes minimal aids necessary for remediating deficits associated with ABI.     

A comparative study to assess the clinical use of Fluorescein Meniscus Time (FMT) with Tear Break up Time (TBUT) and Schirmer's tests (ST) in the diagnosis of dry eyes

INTRODUCTION: The clinical diagnosis of dry-eye is confirmed by a suitable test of tear production and the technique commonly used today to diagnose dry eye is the Schirmer's test (ST). Although the ST is easy to perform it gives variable results, poor reproducibility and low sensitivity for detecting dry eyes. Another test, the tear break up time (TBUT) is used to assess the stability of tears which if abnormal may also cause symptomatic dry-eye. We present the results of both these tests and a new test, which shows greater sensitivity than the ST in detecting aqueous tear deficiency. The fluorescein meniscus time (FMT) is a new test developed in conjunction with one of the authors (CL) and the Department of Ophthalmology at the University Hospital of Wales. The FMT is a measure of the rate at which a fluorescent tear meniscus is formed using 2% sodium fluorescein, a stopwatch and suitable illumination with a slit lamp. METHOD: An open controlled study in 62 patients and 51 controls was conducted to compare the ability of ST, FMT and TBUT to detect dry-eye in a group of patients diagnosed with rheumatoid arthritis and symptomatic dry eyes for a minimum period of 6 months. A separate control group of 15 subjects was tested on three separate occasions to assess the reproducibility of the FMT test. RESULTS: All three tests showed a statistically significant difference between the patient and control populations; Mann-Whitney P < 0.001. There was a correlation between the right and left eye for all three tests in the control group (ST r(2) = 0.77, FMT r(2) = 0.98, TBUT r(2) = 0.94). This correlation was markedly reduced for FMT and TBUT in the patient population and was in keeping with the symptoms reported as being worse on one side in a proportion of the patients (FMT r(2) = 0.52, TBUT r(2) = 0.54, ST r(2) = 0.75). A correlation with age was also observed for all the three tests in the control group (ST r(2) = 0.74, FMT r(2)= 0.92, TBUT r(2) = 0.51), but not in the patient population (ST r(2) = 0.06, FMT r(2) = 0.18, TBUT r(2) = 0.03). A significant correlation was observed between the ST and FMT in both the control (ST vs FMT r(2) = 0.65) and patient population (ST vs FMT r(2) = 0.44). There was no value greater than 200 seconds for FMT recorded in the control group. Using this value to define an abnormal FMT, 85% of the patients (72% of the eyes tested) had an abnormal result. This was in contrast to 35% of patients (26% of the eyes tested) with abnormal results detected by ST. Using ANOVA and Student's paired t-test, there were no significant differences between the three sets of values recorded serially over 3 months to assess the reproducibility of the FMT. The average standard error of the mean was 2.72% and the average co-efficient of variation 4.07%. CONCLUSION: Our study suggests that the FMT is a more sensitive test with good reproducibility compared to the Schirmer's test. The FMT correlates with the ST and suggests that both tests measure aqueous tear deficiency. The FMT therefore is a better alternative to ST currently being used to test aqueous tear deficiency.