Implementation of App-Based Diabetes Medication Management: Outpatient and Perioperative Clinical Decision Support.

PURPOSE OF REVIEW: Outpatient and perioperative therapeutic decision making for patients with diabetes involves increasingly complex medical-decision making due to rapid advances in knowledge and treatment modalities. We sought to review mobile decision support tools available to clinicians for this essential and increasingly difficult task, and to highlight the development and implementation of novel mobile applications for these purposes. RECENT FINDINGS: We found 211 mobile applications related to diabetes from the search, but only five were found to provide clinical decision support for outpatient diabetes management and none for perioperative decision support. We found a dearth of tools for clinicians to navigate these tasks. We highlight key aspects for effective development of future diabetes decision support. These include just-in-time availability, respect for the five rights of clinical decision support, and integration with clinical workflows including the electronic medical record.

Understanding genetic learning needs of people affected by rare disease.

Nearly 350 million people worldwide are affected by a rare disease (RD) and ~80% of RDs have a genetic type, underscoring the need for access to reliable genomics education. Patient assistance in resource development can help ensure content is appropriate. The aim of this study was to define the needs and practical usage of the RD community to inform the scope and content of an online genetic course targeted toward the entire RD ecosystem. A high-level online survey (OS) was disseminated to 586 RD patients and family members/caregivers. A total of 251 individuals responded to the OS. Eight respondents were invited to participate in a follow-up focus group (FG). Nearly 87% of OS respondents have made efforts previously to learn more about genetics and 95.6% indicated a current interest in genetic education. Navigating healthcare systems, information sharing, and advocacy support were driving factors for this desire. Respondents indicated difficulty finding information on gene function, genetic testing, disease pathogenesis, and scientific advances. FG outcomes dove deeper into psychological needs including reducing emotional burden, alleviating fear of the unknown and seeking hope. Research identified high levels of interest in genetic education across all stages of the RD journey. Key themes identified in this study may help guide genetic counselors as they create their own patient and family-facing content.

Diagnostic Utility of Exome Sequencing for Kidney Disease.

BACKGROUND: Exome sequencing is emerging as a first-line diagnostic method in some clinical disciplines, but its usefulness has yet to be examined for most constitutional disorders in adults, including chronic kidney disease, which affects more than 1 in 10 persons globally. METHODS: We conducted exome sequencing and diagnostic analysis in two cohorts totaling 3315 patients with chronic kidney disease. We assessed the diagnostic yield and, among the patients for whom detailed clinical data were available, the clinical implications of diagnostic and other medically relevant findings. RESULTS: In all, 3037 patients (91.6%) were over 21 years of age, and 1179 (35.6%) were of self-identified non-European ancestry. We detected diagnostic variants in 307 of the 3315 patients (9.3%), encompassing 66 different monogenic disorders. Of the disorders detected, 39 (59%) were found in only a single patient. Diagnostic variants were detected across all clinically defined categories, including congenital or cystic renal disease (127 of 531 patients [23.9%]) and nephropathy of unknown origin (48 of 281 patients [17.1%]). Of the 2187 patients assessed, 34 (1.6%) had genetic findings for medically actionable disorders that, although unrelated to their nephropathy, would also lead to subspecialty referral and inform renal management. CONCLUSIONS: Exome sequencing in a combined cohort of more than 3000 patients with chronic kidney disease yielded a genetic diagnosis in just under 10% of cases. (Funded by the National Institutes of Health and others.).

Follow-up of multiple aneuploidies and single monosomies detected by noninvasive prenatal testing: implications for management and counseling.

OBJECTIVES: To determine the underlying biological basis for noninvasive prenatal testing (NIPT) results of multiple aneuploidies or autosomal monosomies. METHODS: Retrospective analysis of 113,415 tests to determine the study cohort, consisting of 138 (0.12%) cases reported as a single autosomal monosomy (n = 65), single trisomy with a sex chromosome aneuploidy (n = 36), or with multiple aneuploidies (n = 37). Clinical outcome information was reviewed and stratified into eight categories according to whether the karyotype or sonographic information agreed or disagreed with sequencing results. RESULTS: Of 67 cases with fetal or neonatal karyotypes available, 16 (24%) were partially or fully concordant with the NIPT result, 4 (6%) had aneuploidy on a reference chromosome, and 47 (70%) had normal fetal chromosomes, in which 5/47 had maternal malignancies reported. One case of maternal mosaic trisomy 8 was also detected. Of cases with no fetal karyotype information, ten had an abnormal clinical outcome, one was a normal live birth, and one reported maternal malignancy. CONCLUSIONS: Noninvasive prenatal test results of autosomal monosomy or multiple aneuploidies are rare but have a diversity of underlying biologic causes. Some reflect the fetal karyotype; some reflect the presence of other maternal or fetal chromosome abnormalities, and a small number are linked to maternal disease.

Noninvasive prenatal testing in the general obstetric population: clinical performance and counseling considerations in over 85 000 cases.

OBJECTIVE: The primary goal of this study was to provide clinically relevant information for appropriate patient counseling. METHOD: Demographics and test metrics were reviewed for 86 658 clinical cases. Outcome information was requested for samples reported as aneuploidy detected or suspected for chromosomes 21, 18, or 13; voluntary outcome reporting was encouraged for all discordant outcomes. RESULTS: Of 86 658 cases, 85 298 (98.4%) met inclusion criteria for result reporting. Of the 1360 (1.6%) cancellations, only 101 (0.1%) were for technical reasons. Average time to result was 3.3 business days. Aneuploidy was detected or suspected in 2142 (2.5%) samples. For aneuploidy detected cases with known clinical outcomes, the overall positive predictive value (PPV) was 83.5% (608/728); observed PPVs for trisomies 21, 18, and 13 ranged from 50.0 to 92.8%. As individual PPVs are determined by a patient's prior risk, we developed a chart for counseling patients on positive predictive value based on maternal age. CONCLUSION: This large-scale report reinforces that noninvasive prenatal testing is a highly accurate screen for fetal aneuploidy in the general obstetric population. Test improvements have facilitated a reduction in failure rates, time to result, and borderline results/unclassifiable results. We have developed a positive predictive value counseling tool to ensure appropriate patient education, counseling, and clinical utilization.

Discovery of new risk loci for IgA nephropathy implicates genes involved in immunity against intestinal pathogens.

We performed a genome-wide association study (GWAS) of IgA nephropathy (IgAN), the most common form of glomerulonephritis, with discovery and follow-up in 20,612 individuals of European and East Asian ancestry. We identified six new genome-wide significant associations, four in ITGAM-ITGAX, VAV3 and CARD9 and two new independent signals at HLA-DQB1 and DEFA. We replicated the nine previously reported signals, including known SNPs in the HLA-DQB1 and DEFA loci. The cumulative burden of risk alleles is strongly associated with age at disease onset. Most loci are either directly associated with risk of inflammatory bowel disease (IBD) or maintenance of the intestinal epithelial barrier and response to mucosal pathogens. The geospatial distribution of risk alleles is highly suggestive of multi-locus adaptation, and genetic risk correlates strongly with variation in local pathogens, particularly helminth diversity, suggesting a possible role for host-intestinal pathogen interactions in shaping the genetic landscape of IgAN.

Impact of noninvasive prenatal testing in regionally dispersed medical centers in the United States.

OBJECTIVE: Noninvasive prenatal testing using cell-free DNA is a new alternative to screen for common fetal aneuploidies. It is not known what impact regional location may play on noninvasive prenatal testing implementation and downstream invasive prenatal procedure use in the United States. STUDY DESIGN: Six different regionally based centers collected data on noninvasive prenatal testing indication and results between February and November 2012, as well as their invasive prenatal procedure rates before and after offering noninvasive prenatal testing. Statistical analyses were performed using the 2-proportion Z-test. RESULTS: Of 1477 patients who underwent noninvasive prenatal testing; 693 (47%) were from centers in the West; 522 (35.3%) from centers in the East; and 262 (17.7%) from 1 center in the Midwest. Statistically significant differences were observed between West Coast and nonWest Coast sites for gestational age (14.1 weeks; P ≤ .0001). Advanced maternal age (AMA-only) was the most frequent indication in 5 of 6 sites (range, 21.8-62.9%) A total of 98 invasive prenatal procedures performed on 94 (6.4%) patients of which 64 (65.3%) were performed at centers in the West. More invasive procedures were performed following negative noninvasive prenatal testing results (n = 61) than abnormal noninvasive prenatal testing results (n = 30). The overall rate of patients undergoing invasive procedure after an abnormal noninvasive prenatal testing result was 32.6% (30 of 92). All 6 centers reported a decrease in invasive procedure volume after noninvasive prenatal testing introduction. CONCLUSION: This study demonstrates differences in clinical implementation of noninvasive prenatal testing across regionally dispersed centers in the United States, suggesting patient demographics and views toward prenatal testing influence use as well as downstream management.

Lack of serologic evidence to link IgA nephropathy with celiac disease or immune reactivity to gluten.

IgA nephropathy is the most common form of primary glomerulonephritis worldwide. Mucosal infections and food antigens, including wheat gluten, have been proposed as potential contributing environmental factors. Increased immune reactivity to gluten and/or association with celiac disease, an autoimmune disorder triggered by ingestion of gluten, have been reported in IgA nephropathy. However, studies are inconsistent about this association. We aimed to evaluate the proposed link between IgA nephropathy and celiac disease or immune reactivity to gluten by conducting a comprehensive analysis of associated serologic markers in cohorts of well-characterized patients and controls. Study participants included patients with biopsy-proven IgA nephropathy (n = 99), unaffected controls of similar age, gender, and race (n = 96), and patients with biopsy-proven celiac disease (n = 30). All serum specimens were tested for IgG and IgA antibodies to native gliadin and deamidated gliadin, as well as IgA antibody to transglutaminase 2 (TG2). Anti-TG2 antibody-positive nephropathy patients and unaffected controls were subsequently tested for IgA anti-endomysial antibody and genotyped for celiac disease-associated HLA-DQ2 and -DQ8 alleles. In comparison to unaffected controls, there was not a statistically significant increase in IgA or IgG antibody reactivity to gliadin in individuals with IgA nephropathy. In addition, the levels of celiac disease-specific serologic markers, i.e., antibodies to deamidated gliadin and TG2, did not differ between IgA nephropathy patients and unaffected controls. Results of the additional anti-endomysial antibody testing and HLA genotyping were corroborative. The data from this case-control study do not reveal any evidence to suggest a significant role for celiac disease or immune reactivity to gluten in IgA nephropathy.

Next Generation sequencing is the impetus for the next generation of laboratory-based genetic counselors.

Next generation sequencing (NGS) is dramatically increasing the number of clinically available genetic tests and thus the number of patients in which such testing may be indicated. The complex nature and volume of the reported results requires professional interpretation of the testing in order to translate and synthesize the meaning and potential benefit to patients, and genetic counselors are uniquely suited to provide this service. The increased need for genetic counselors in this role, coupled with the time required and a limited number of trained and available counselors presents a challenge to current models for making genetic testing available to patients and their healthcare providers effectively and efficiently. The employment of genetic counselors at genetic/genomic laboratories is one model to expand the resources for providing this service. In this article, we briefly review the advent of NGS and its clinical applications, examine the core skills of genetic counselors and delineate the expanding roles and responsibilities of laboratory-based genetic counselors. We also propose changes to the genetic counseling training program curriculum to account for the increasing opportunities for genetic counselors to contribute and thrive within genetic testing laboratories.

Nutritional control of antibiotic resistance via an interface between the phosphotransferase system and a two-component signaling system.

Enterococci are ubiquitous inhabitants of the gastrointestinal (GI) tract. However, antibiotic-resistant enterococci are also major causes of hospital-acquired infections. Enterococci are intrinsically resistant to cephalosporins, enabling growth to abnormally high densities in the GI tract in patients during cephalosporin therapy, thereby promoting dissemination to other sites where they cause infection. Despite its importance, many questions about the underlying basis for cephalosporin resistance remain. A specific two-component signaling system, composed of the CroS sensor kinase and its cognate response regulator (CroR), is required for cephalosporin resistance in Enterococcus faecalis, but little is known about the factors that control this signaling system to modulate resistance. To explore the signaling network in which CroR participates to influence cephalosporin resistance, we employed a protein fragment complementation assay to detect protein-protein interactions in E. faecalis cells, revealing a previously unknown association of CroR with the HPr protein of the phosphotransferase system (PTS) responsible for carbohydrate uptake and catabolite control of gene expression. Genetic and physiological analyses indicate that association with HPr restricts the ability of CroR to promote cephalosporin resistance and gene expression in a nutrient-dependent manner. Mutational analysis suggests that the interface used by HPr to associate with CroR is distinct from the interface used to associate with other cellular partners. Our results define a physical and functional connection between a critical nutrient-responsive signaling system (the PTS) and a two-component signaling system that drives antibiotic resistance in E. faecalis, and they suggest a general strategy by which bacteria can integrate their nutritional status with diverse environmental stimuli.

Geographic differences in genetic susceptibility to IgA nephropathy: GWAS replication study and geospatial risk analysis.

IgA nephropathy (IgAN), major cause of kidney failure worldwide, is common in Asians, moderately prevalent in Europeans, and rare in Africans. It is not known if these differences represent variation in genes, environment, or ascertainment. In a recent GWAS, we localized five IgAN susceptibility loci on Chr.6p21 (HLA-DQB1/DRB1, PSMB9/TAP1, and DPA1/DPB2 loci), Chr.1q32 (CFHR3/R1 locus), and Chr.22q12 (HORMAD2 locus). These IgAN loci are associated with risk of other immune-mediated disorders such as type I diabetes, multiple sclerosis, or inflammatory bowel disease. We tested association of these loci in eight new independent cohorts of Asian, European, and African-American ancestry (N = 4,789), followed by meta-analysis with risk-score modeling in 12 cohorts (N = 10,755) and geospatial analysis in 85 world populations. Four susceptibility loci robustly replicated and all five loci were genome-wide significant in the combined cohort (P = 5×10⁻³²-3×10⁻¹°), with heterogeneity detected only at the PSMB9/TAP1 locus (I²â€Š= 0.60). Conditional analyses identified two new independent risk alleles within the HLA-DQB1/DRB1 locus, defining multiple risk and protective haplotypes within this interval. We also detected a significant genetic interaction, whereby the odds ratio for the HORMAD2 protective allele was reversed in homozygotes for a CFHR3/R1 deletion (P = 2.5×10⁻4). A seven-SNP genetic risk score, which explained 4.7% of overall IgAN risk, increased sharply with Eastward and Northward distance from Africa (r = 0.30, P = 3×10⁻¹²8). This model paralleled the known East-West gradient in disease risk. Moreover, the prediction of a South-North axis was confirmed by registry data showing that the prevalence of IgAN-attributable kidney failure is increased in Northern Europe, similar to multiple sclerosis and type I diabetes. Variation at IgAN susceptibility loci correlates with differences in disease prevalence among world populations. These findings inform genetic, biological, and epidemiological investigations of IgAN and permit cross-comparison with other complex traits that share genetic risk loci and geographic patterns with IgAN.

Iridescent colour production in hairs of blind golden moles (Chrysochloridae).

Relative to other metazoans, the mammalian integument is thought to be limited in colour. In particular, while iridescence is widespread among birds and arthropods, it has only rarely been reported in mammals. Here, we examine the colour, morphology and optical mechanisms in hairs from four species of golden mole (Mammalia: Chrysochloridae) that are characterized by sheens ranging from purple to green. Microspectrophotometry reveals that this colour is weak and variable. Iridescent hairs are flattened and have highly reduced cuticular scales, providing a broad and smooth surface for light reflection. These scales form multiple layers of light and dark materials of consistent thickness, strikingly similar to those in the elytra of iridescent beetles. Optical modelling suggests that the multi-layers produce colour through thin-film interference, and that the sensitivity of this mechanism to slight changes in layer thickness and number explains colour variability. While coloured integumentary structures are typically thought to evolve as sexual ornaments, the blindness of golden moles suggests that the colour may be an epiphenomenon resulting from evolution via other selective factors, including the ability to move and keep clean in dirt and sand.

The entomopathogenic bacterial endosymbionts Xenorhabdus and Photorhabdus: convergent lifestyles from divergent genomes.

Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, with both partners contributing to insect pathogenesis and the bacteria providing nutrition to the nematode from available insect-derived nutrients. The nematode provides the bacteria with protection from predators, access to nutrients, and a mechanism of dispersal. Members of the bacterial genus Photorhabdus also associate with nematodes to kill insects, and both genera of bacteria provide similar services to their different nematode hosts through unique physiological and metabolic mechanisms. We posited that these differences would be reflected in their respective genomes. To test this, we sequenced to completion the genomes of Xenorhabdus nematophila ATCC 19061 and Xenorhabdus bovienii SS-2004. As expected, both Xenorhabdus genomes encode many anti-insecticidal compounds, commensurate with their entomopathogenic lifestyle. Despite the similarities in lifestyle between Xenorhabdus and Photorhabdus bacteria, a comparative analysis of the Xenorhabdus, Photorhabdus luminescens, and P. asymbiotica genomes suggests genomic divergence. These findings indicate that evolutionary changes shaped by symbiotic interactions can follow different routes to achieve similar end points.

APOL1 variants increase risk for FSGS and HIVAN but not IgA nephropathy.

A chromosome 22q13 locus strongly associates with increased risk for idiopathic focal segmental glomerulosclerosis (FSGS), HIV-1-associated nephropathy (HIVAN), and hypertensive ESRD among individuals of African descent. Although initial studies implicated MYH9, more recent analyses localized the strongest association within the neighboring APOL1 gene. In this replication study, we examined the six top-most associated variants in APOL1 and MYH9 in an independent cohort of African Americans with various nephropathies (44 with FSGS, 21 with HIVAN, 32 with IgA nephropathy, and 74 healthy controls). All six variants associated with FSGS and HIVAN (additive ORs, 1.8 to 3.0; P values 3 × 10(-2) to 5 × 10(-5)) but not with IgA nephropathy. In conditional and haplotype analyses, two APOL1 haplotypes accounted for virtually all of the association with FSGS and HIVAN on chromosome 22q13 (haplotype P value = 5.6 × 10(-8)). To assess the role of MYH9 deficiency in nephropathy, we crossbred Myh9-haploinsufficient mice (Myh9(+/-)) with HIV-1 transgenic mice. Myh9(+/-) mice were healthy and did not demonstrate overt proteinuria or nephropathy, irrespective of the presence of the HIV-1 transgene. These data further support the strong association of genetic variants in APOL1 with susceptibility to FSGS and HIVAN among African Americans.

Role of Mrx fimbriae of Xenorhabdus nematophila in competitive colonization of the nematode host.

Xenorhabdus nematophila engages in mutualistic associations with the infective juvenile (IJ) stage of specific entomopathogenic nematodes. Mannose-resistant (Mrx) chaperone-usher-type fimbriae are produced when the bacteria are grown on nutrient broth agar (NB agar). The role of Mrx fimbriae in the colonization of the nematode host has remained unresolved. We show that X. nematophila grown on LB agar produced flagella rather than fimbriae. IJs propagated on X. nematophila grown on LB agar were colonized to the same extent as those propagated on NB agar. Further, progeny IJs were normally colonized by mrx mutant strains that lacked fimbriae both when bacteria were grown on NB agar and when coinjected into the insect host with aposymbiotic nematodes. The mrx strains were not competitively defective for colonization when grown in the presence of wild-type cells on NB agar. In addition, a phenotypic variant strain that lacked fimbriae colonized as well as the wild-type strain. In contrast, the mrx strains displayed a competitive colonization defect in vivo. IJ progeny obtained from insects injected with comixtures of nematodes carrying either the wild-type or the mrx strain were colonized almost exclusively with the wild-type strain. Likewise, when insects were coinjected with aposymbiotic IJs together with a comixture of the wild-type and mrx strains, the resulting IJ progeny were predominantly colonized with the wild-type strain. These results revealed that Mrx fimbriae confer a competitive advantage during colonization in vivo and provide new insights into the role of chaperone-usher fimbriae in the life cycle of X. nematophila.

Image-guided drainage of pericardial effusions in oncology patients.

The purpose of this study was to report our clinical experience with image-guided drainage of pericardial effusions in oncology patients. IRB approval was obtained for this retrospective, HIPAA-compliant study. From November 2002 to January 2008, 40 patients underwent 43 image-guided drainages of pericardial effusions. The medical records were reviewed to analyze the technical aspects of the procedures, complications, and clinical outcomes. Thirty-three pericardial drains were placed and 10 pericardiocenteses were performed. The technical success rate was 100%. Thirty-three procedures were performed under computed tomographic (CT) guidance, five under ultrasound (US) guidance, and five using both CT and US guidance. There were no technical, procedure-related complications. Delayed postprocedure complications and arrhythmias occurred in 11 cases, for an overall complication rate of 25.6%. All complications occurred in patients who had undergone drain placement. Nine patients developed new or worsening arrhythmias and six of these patients required transfer to a higher level of care or the initiation of pharmacological management. In 58.6% of drain placements, including 4 of 11 patients who developed complications, the catheter could have been removed earlier. The median overall survival was 6.47 months (95% CI: 2.37, 12.7). In conclusion, image-guided pericardial drain placement is safe and feasible. Due to the frequency of delayed postprocedure arrhythmias, follow-up monitoring in a telemetry unit is recommended. Prompt catheter removal after drainage may reduce the incidence of delayed post-catheter-insertion arrhythmias.

New insights into the colonization and release processes of Xenorhabdus nematophila and the morphology and ultrastructure of the bacterial receptacle of its nematode host, Steinernema carpocapsae.

We present results from epifluorescence, differential interference contrast, and transmission electron microscopy showing that Xenorhabdus nematophila colonizes a receptacle in the anterior intestine of the infective juvenile (IJ) stage of Steinernema carpocapsae. This region is connected to the esophagus at the esophagointestinal junction. The process by which X. nematophila leaves this bacterial receptacle had not been analyzed previously. In this study we monitored the movement of green fluorescent protein-labeled bacteria during the release process. Our observations revealed that Xenorhabdus colonizes the distal region of the receptacle and that exposure to insect hemolymph stimulated forward movement of the bacteria to the esophagointestinal junction. Continued exposure to hemolymph caused a narrow passage in the distal receptacle to widen, allowing movement of Xenorhabdus down the intestine and out the anus. Efficient release of both the wild type and a nonmotile strain was evident in most of the IJs incubated in hemolymph, whereas only a few IJs incubated in nutrient-rich broth released bacterial cells. Incubation of IJs in hemolymph treated with agents that induce nematode paralysis dramatically inhibited the release process. These results suggest that bacterial motility is not required for movement out of the distal region of the receptacle and that hemolymph-induced esophageal pumping provides a force for the release of X. nematophila out of the receptacle and into the intestinal lumen.

Spreadsheet use to calculate creatinine clearance from serum creatinine.

Spreadsheets may be created to include the Cockcroft-Gault Formula (CGF) for creatinine-based estimation of glomerular filtration rate. Creatinine clearance (CrCl) provides a more accurate method for perioperative risk assessment of renal function than serum creatinine. CrCl may be used to develop guidelines for renal protective management strategies during cardiopulmonary bypass. CGF uses serum creatinine, age, kilogram weight, sex, and "logical test" functions within the spreadsheet to calculate the CrCl. Implementation of spreadsheets has the potential for numerous other calculations and may provide an accurate and consistent method of clinical perfusion management.

Unique organization and regulation of the mrx fimbrial operon in Xenorhabdus nematophila.

Xenorhabdus nematophila, a Gram-negative bacterium belonging to the Proteus clade of the family Enterobacteriaceae, forms a mutualistic association with the soil nematode Steinernema carpocapsae. The nematode invades insects and releases Xenorhabdus into the haemolymph, where it participates in insect killing. To begin to understand the role of fimbriae in the unique life cycle of Xenorhabdus, the organization and expression of the mrx fimbrial operon was analysed. The mrx operon contained only five structural genes (mrxACDGH), making it one of the smallest chaperone-usher fimbrial operons studied to date. Unlike the mrp operon of Proteus mirabilis, a site-specific recombinase was not linked to the mrx operon. The intergenic region between the major fimbrial gene (mrxA) and the usher gene (mrxC) lacked a mrpB-like gene, but contained three tandem inverted repeat sequences located downstream of mrxA. A 940 nt mrxA-containing mRNA was the major transcript produced in cells growing on agar, while an mrx polycistronic mRNA was produced at low levels. A canonical sigma(70) promoter, identified upstream of mrxA, was not subject to promoter inversion. Fimbriae were not produced in an lrp-mutant strain, suggesting that the leucine-responsive regulatory protein, Lrp, plays a role in the regulation of the mrx operon. These findings show that the genetic organization and regulation of the mrx operon is in several respects distinct from other chaperone-usher fimbrial operons.