Utilization of RNA sequencing to investigate olfactory dysfunction in chronic rhinosinusitis without nasal polyps: A pilot study.

Objectives: Prior research on olfactory dysfunction in chronic rhinosinusitis (CRS) has focused on patients with polyps and suggests that direct inflammation of the olfactory cleft mucosa plays a contributory role. The purpose of this study was to evaluate gene expression in superior turbinate mucosal specimens, comparing normosmic and dysosmic CRS patients without polyps (CRSsNP). Methods: Tissue samples were obtained from the superior turbinates of patients with CRSsNP at the time of endoscopic sinus surgery. Samples subsequently underwent RNA sequencing and functional analysis to investigate biological pathways associated with differentially expressed genes between dysosmic (n = 7) and normosmic (n = 4) patients. Results: Differential gene expression analysis comparing dysosmic and normosmic CRSsNP patients showed upregulation of 563 genes and downregulation of 327 genes. Using stringent criteria for multiple comparisons, one upregulated gene (Immediate Early Response 3 [IER3]) had an false discovery rate (FDR) correction adjusted P value considered statistically significant (P < 0.001, fold change 2.69). Reactome functional analysis revealed eight biological pathways significantly different between dysosmic and normosmic patients (P < 0.05, FDR correction) including IL-4 and IL-13 signaling, IL-10 signaling, and rhodopsin-like receptors. Conclusions: RNA sequencing of the superior turbinates in patients with CRSsNP can provide valuable information regarding biological pathways and genes involved in olfactory dysfunction. This study supports literature suggesting that Type 2 inflammation may play a role in olfactory dysfunction in at least some patients with CRSsNP. This study also prompts questions regarding the role of IL-10, rhodopsin-like receptors, and IER3 in the pathogenesis of olfactory dysfunction.

Comparison of trigeminal lateralization with differing stimulants.

Trigeminal-specific stimulants have been shown to activate different receptors preferentially and this likely accounts for variation in sensory perception. It is unclear whether trigeminal sensitivity is similar across different transient receptor potential (TRP) receptors or if dysfunction of different receptors results in differing patient symptoms. Therefore, a prospective cohort study was conducted, consisting of trigeminal lateralization testing with three different stimulants (eucalyptol, isothiocyanate, acetic acid), olfaction testing with Sniffin' Sticks, and measurement of various patient-reported outcome measures (PROMs). A total of 50 participants were enrolled across the olfactory spectrum. Mean TDI score was 27.1 ± 8.3 (range 7.0-39.5) with 38% normosmic and 62% dysosmic. Mean trigeminal lateralization scores out of 20 in the overall cohort were 16.18 (2.78) for eucalyptol, 14.94 (3.49) for mustard oil, and 15.28 (3.68) for vinegar. Eucalyptol showed a significant correlation with threshold scores of Sniffin' Sticks. A significant correlation was found between acetic acid and various PROMs. None of the lateralization scores of the trigeminal stimulants correlated to each other significantly and there was no correlation to age. The lack of correlation suggests that the measured sensitivity of one type of TRP receptor may not translate to similar sensitivity of the other receptors. Additional investigations with TRPV1 and TRPA1 agonists are needed to corroborate our findings.

Patient experiences and perceived value of genetic testing in inherited retinal diseases: a cross-sectional survey.

This study evaluated patient experiences with genetic testing for inherited retinal diseases (IRDs) and the association between underlying knowledge, testing outcomes, and the perceived value of the results. An online survey was distributed to adults with IRDs and parents/guardians of dependents with IRDs who had had genetic testing. Data included details of genetic testing, pre- and post- test perceptions, Decision Regret Scale, perceived value of results, and knowledge of gene therapy. Of 135 responses (85% from adults with IRDs), genetic testing was primarily conducted at no charge through public hospitals (49%) or in a research setting (30%). Key motivations for genetic testing were to confirm IRD diagnosis and to contribute towards research. Those who had received a genetic diagnosis (odds ratio: 6.71; p < 0.001) and those self-reported to have good knowledge of gene therapy (odds ratio: 2.69; p = 0.018) were more likely to have gained confidence in managing their clinical care. For over 80% of respondents, knowing the causative gene empowered them to learn more about their IRD and explore opportunities regarding clinical trials. Key genetic counselling information needs include resources for family communications, structured information provision, and ongoing genetic support, particularly in the context of emerging ocular therapies, to enhance consistency in information uptake.

Crystal structure and biophysical characterization of IspD from Burkholderia thailandensis and Mycobacterium paratuberculosis.

The methylerythritol phosphate (MEP) pathway is a metabolic pathway that produces the isoprenoids isopentyl pyrophosphate and dimethylallyl pyrophosphate. Notably, the MEP pathway is present in bacteria and not in mammals, which makes the enzymes of the MEP pathway attractive targets for discovering new anti-infective agents due to the reduced chances of off-target interactions leading to side effects. There are seven enzymes in the MEP pathway, the third of which is IspD. Two crystal structures of Burkholderia thailandensis IspD (BtIspD) were determined: an apo structure and that of a complex with cytidine triphosphate (CTP). Comparison of the CTP-bound BtIspD structure with the apo structure revealed that CTP binding stabilizes the loop composed of residues 13-19. The apo structure of Mycobacterium paratuberculosis IspD (MpIspD) is also reported. The melting temperatures of MpIspD and BtIspD were evaluated by circular dichroism. The moderate Tm values suggest that a thermal shift assay may be feasible for future inhibitor screening. Finally, the binding affinity of CTP for BtIspD was evaluated by isothermal titration calorimetry. These structural and biophysical data will aid in the discovery of IspD inhibitors.

Genetic analysis and molecular basis of G6PD deficiency among malaria patients in Thailand: implications for safe use of 8-aminoquinolines.

BACKGROUND: It was hypothesized that glucose-6-phosphate dehydrogenase (G6PD) deficiency confers a protective effect against malaria infection, however, safety concerns have been raised regarding haemolytic toxicity caused by radical cure with 8-aminoquinolines in G6PD-deficient individuals. Malaria elimination and control are also complicated by the high prevalence of G6PD deficiency in malaria-endemic areas. Hence, accurate identification of G6PD deficiency is required to identify those who are eligible for malaria treatment using 8-aminoquinolines. METHODS: The prevalence of G6PD deficiency among 408 Thai participants diagnosed with malaria by microscopy (71), and malaria-negative controls (337), was assessed using a phenotypic test based on water-soluble tetrazolium salts. High-resolution melting (HRM) curve analysis was developed from a previous study to enable the detection of 15 common missense, synonymous and intronic G6PD mutations in Asian populations. The identified mutations were subjected to biochemical and structural characterisation to understand the molecular mechanisms underlying enzyme deficiency. RESULTS: Based on phenotypic testing, the prevalence of G6PD deficiency (< 30% activity) was 6.13% (25/408) and intermediate deficiency (30-70% activity) was found in 15.20% (62/408) of participants. Several G6PD genotypes with newly discovered double missense variants were identified by HRM assays, including G6PD Gaohe + Viangchan, G6PD Valladolid + Viangchan and G6PD Canton + Viangchan. A significantly high frequency of synonymous (c.1311C>T) and intronic (c.1365-13T>C and c.486-34delT) mutations was detected with intermediate to normal enzyme activity. The double missense mutations were less catalytically active than their corresponding single missense mutations, resulting in severe enzyme deficiency. While the mutations had a minor effect on binding affinity, structural instability was a key contributor to the enzyme deficiency observed in G6PD-deficient individuals. CONCLUSIONS: With varying degrees of enzyme deficiency, G6PD genotyping can be used as a complement to phenotypic screening to identify those who are eligible for 8-aminoquinolines. The information gained from this study could be useful for management and treatment of malaria, as well as for the prevention of unanticipated reactions to certain medications and foods in the studied population.

The use of a kaolin-based hemostatic dressing to attenuate bleeding in dogs: A series of 4 cases.

OBJECTIVE: To describe the use of a synthetic hemostatic dressing, QuikClot Combat Gauze (QCG), in dogs with bleeding wounds. CASE SERIES SUMMARY: Two dogs presented with bleeding traumatic wounds, and QCG was used to achieve hemostasis during stabilization of these dogs. In the other 2 dogs, QCG was used to help attenuate bleeding associated with a surgical procedure. NEW OR UNIQUE INFORMATION PROVIDED: While hemostatic dressings have been widely studied and used in human medicine, there is minimal information on the use and efficacy of these hemostatic dressings in veterinary medicine. This case series describes the use of QCG in dogs with hemorrhaging wounds. QCG could be a valuable resource in veterinary emergency and critical care settings.

Optical coherence tomography in children with inherited retinal disease.

Recent advances have led to therapeutic options becoming available for people with inherited retinal disease. In particular, gene therapy has been shown to hold great promise for slowing vision loss from inherited retinal disease. Recent studies suggest that gene therapy is likely to be most effective when implemented early in the disease process, making consideration of paediatric populations important. It is therefore necessary to have a comprehensive understanding of retinal imaging in children with inherited retinal diseases, in order to monitor disease progression and to determine which early retinal biomarkers may be used as outcome measures in future clinical trials. In addition, as many optometrists will review children with an inherited retinal disease, an understanding of the expected imaging outcomes can improve clinical care. This review focuses on the most common imaging modality used in research assessment of paediatric inherited retinal diseases: optical coherence tomography. Optical coherence tomography findings can be used in both the clinical and research setting. In particular, the review discusses current knowledge of optical coherence tomography findings in eight paediatric inherited retinal diseases - Stargardt disease, Bests disease, Leber's congenital amaurosis, choroideremia, RPGR related retinitis pigmentosa, Usher syndrome, X-linked retinoschisis and, Batten disease.

Chimeric antigens displaying GPR65 extracellular loops on a soluble scaffold enabled the discovery of antibodies, which recognized native receptor.

GPR65 is a proton-sensing G-protein coupled receptor associated with multiple immune-mediated inflammatory diseases, whose function is relatively poorly understood. With few reagents commercially available to probe the biology of receptor, generation of an anti-GPR65 monoclonal antibody was desired. Using soluble chimeric scaffolds, such as ApoE3, displaying the extracellular loops of GPR65, together with established phage display technology, native GPR65 loop-specific antibodies were identified. Phage-derived loop-binding antibodies recognized the wild-type native receptor to which they had not previously been exposed, generating confidence in the use of chimeric soluble proteins to act as efficient surrogates for membrane protein extracellular loop antigens. This technique provides promise for the rational design of chimeric antigens in facilitating the discovery of specific antibodies to GPCRs.

This technique offers a viable approach for antibody discovery to difficult GPCRs.Structurally relevant, soluble chimeric scaffold proteins of GPR65 were generated.Chimeric antigens were used to identify GPR65-specific antibodies by phage display.

Perspectives of carriers of X-linked retinal diseases on genetic testing and gene therapy: A global survey.

Female carriers of X-linked inherited retinal diseases (IRDs) are burdened with potentially passing their disease-causing variant to future generations, as well as exhibiting signs of retinal disease themselves. This study aimed to investigate carriers' experiences of genetic testing, emotions relating to having affected children, and their knowledge regarding genetic testing and gene therapy. An online survey was advertised to self-identified carriers worldwide. Two hundred and twenty-eight carriers completed the survey with mean age of 51 years (SD ± 15.0). A majority of respondents resided in the United States of America (51%), Australia (19%), and the United Kingdom (14%). Most carriers identified with feelings of guilt (70%), concern (91%), and anxiety (88%) for their child. Female carriers who had given birth to children had significantly greater gene therapy knowledge compared to carriers who had not (p < 0.05). Respondents agreed that their eyecare provider and general practitioner helped them understand their condition (63%), however, few carriers reported receiving psychological counselling (9%) or family planning advice (5%). Most respondents (78%) agreed that gene therapy should be available to carriers. This study emphasises the importance of providing appropriate counselling to female carriers and illustrates the motivation of many to participate in emerging treatment options, such as gene therapy.

In vitro evaluation of hyperosmotic canine plasma suitable for infusion.

OBJECTIVE: To determine the characteristics of canine freeze-dried plasma (cFDP) as it is serially diluted with sterile water. DESIGN: In vitro experimental study. SETTING: Government blood and coagulation research laboratory. ANIMALS: cFDP from a commercial manufacturer. INTERVENTIONS: Ten units of cFDP were reconstituted to 100%, 90%, 80%, 70%, 60%, 50%, and 40% of the recommended volume with sterile water. The resultant solutions were analyzed for coagulation factor activity (factors II, V, VII, VIII, IX, X, and XII as well as antithrombin), fibrinogen concentration, prothrombin time, activated partial thromboplastin time, viscosity, osmolality, and kaolin-activated thromboelastography. MEASUREMENTS AND MAIN RESULTS: Viscosity, osmolality, and turbidity properties of plasma were increased in a reconstitution volume-dependent manner, with the 40% suggested volume generating approximately 2-fold increases in each. Similarly, factor activity levels and fibrinogen concentration increased by approximately 2-fold over this range in a concentration-dependent manner. Prothrombin time declined from 11.4 seconds at 100% volume to 10.9 seconds at 70% before increasing to 11.9 seconds at 40%. Activated partial thromboplastin time increased exponentially from 21.8 seconds at 100% rehydration to 100.0 seconds at 40%. R-time on TEG increased from 3.1 to 13.9 minutes at 50% rehydration, while alpha angle declined from 61.3° to 24.7° over the same range, and the maximum amplitude initially increased from 13.2 mm at 100% water to 18.6 mm at 70% water before dropping back down to 14.6 mm at 50% water. No clotting was observed with 40% rehydration. CONCLUSIONS: The creation of hyperosmotic plasma from cFDP appears feasible with preservation of concentrated coagulation factors, although there are some unexplained effects that happen to coagulation functions at the highest concentrations tested using only 40%-50% of recommended rehydration volume. Further studies are needed to evaluate the hyperosmotic product in vivo.

Allergy and Asthma Prevalence and Management Across Nasal Polyp Subtypes.

Allergy and asthma prevalence vary across different subsets of chronic rhinosinusitis with nasal polyposis. In this article, the authors investigate the management of allergy and asthma within populations of patients with aspirin-exacerbated respiratory disease, allergic fungal rhinosinusitis, and central compartment atopic disease. Topical steroids, nasal rinses, and endoscopic sinus surgery are frequently employed in the management of nasal polyposis. Further, other causes of upper and lower airway inflammation like allergy and asthma should be considered in the overall treatment plan in order to optimize outcomes.

Adaptive optics imaging in inherited retinal diseases: A scoping review of the clinical literature.

Adaptive optics (AO) imaging enables direct, objective assessments of retinal cells. Applications of AO show great promise in advancing our understanding of the etiology of inherited retinal disease (IRDs) and discovering new imaging biomarkers. This scoping review systematically identifies and summarizes clinical studies evaluating AO imaging in IRDs. Ovid MEDLINE and EMBASE were searched on February 6, 2023. Studies describing AO imaging in monogenic IRDs were included. Study screening and data extraction were performed by 2 reviewers independently. This review presents (1) a broad overview of the dominant areas of research; (2) a summary of IRD characteristics revealed by AO imaging; and (3) a discussion of methodological considerations relating to AO imaging in IRDs. From 140 studies with AO outcomes, including 2 following subretinal gene therapy treatments, 75% included fewer than 10 participants with AO imaging data. Of 100 studies that included participants' genetic diagnoses, the most common IRD genes with AO outcomes are CNGA3, CNGB3, CHM, USH2A, and ABCA4. Confocal reflectance AO scanning laser ophthalmoscopy was the most reported imaging modality, followed by flood-illuminated AO and split-detector AO. The most common outcome was cone density, reported quantitatively in 56% of studies. Future research areas include guidelines to reduce variability in the reporting of AO methodology and a focus on functional AO techniques to guide the development of therapeutic interventions.

Genetic testing and gene therapy in retinal diseases: Knowledge and perceptions of optometrists in Australia and New Zealand.

With advances in gene-based therapies for heritable retinal diseases, primary eye care clinicians should be informed on ocular genetics topics. This cross-sectional survey evaluated knowledge, attitudes, and concerns regarding genetic testing and gene therapy for retinal diseases among optometrists in Australia and New Zealand. Survey data included practitioner background, attitudes and practices towards genetic testing for monogenic inherited retinal disease (IRDs) and age-related macular degeneration, and knowledge of ocular genetics and gene therapy. Responses were received from 516 optometrists between 1 April and 31 December 2022. Key perceived barriers to accessing genetic testing were lack of clarity on referral pathways (81%), cost (65%), and lack of treatment options if a genetic cause is identified (50%). Almost all respondents (98%) believed that ophthalmologists should initiate genetic testing for IRDs and fewer understood the role of genetic counsellors and clinical geneticists. This study found that optometrists in Australia and New Zealand have a high level of interest in ocular genetics topics. However, knowledge gaps include referral pathways and awareness of genetic testing and gene therapy outcomes. Addressing perceived barriers to access and promoting sharing of knowledge between interdisciplinary networks can set the foundation for genetic education agendas in primary eye care.

Molecular characterization of G6PD mutations identifies new mutations and a high frequency of intronic variants in Thai females.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzymopathy caused by mutations in the G6PD gene. A medical concern associated with G6PD deficiency is acute hemolytic anemia induced by certain foods, drugs, and infections. Although phenotypic tests can correctly identify hemizygous males, as well as homozygous and compound heterozygous females, heterozygous females with a wide range of G6PD activity may be misclassified as normal. This study aimed to develop multiplex high-resolution melting (HRM) analyses to enable the accurate detection of G6PD mutations, especially among females with heterozygous deficiency. Multiplex HRM assays were developed to detect six G6PD variants, i.e., G6PD Gaohe (c.95A>G), G6PD Chinese-4 (c.392G>T), G6PD Mahidol (c.487G>A), G6PD Viangchan (c.871G>A), G6PD Chinese-5 (c.1024C>T), and G6PD Union (c.1360C>T) in two reactions. The assays were validated and then applied to genotype G6PD mutations in 248 Thai females. The sensitivity of the HRM assays developed was 100% [95% confidence interval (CI): 94.40%-100%] with a specificity of 100% (95% CI: 88.78%-100%) for detecting these six mutations. The prevalence of G6PD deficiency was estimated as 3.63% (9/248) for G6PD deficiency and 31.05% (77/248) for intermediate deficiency by phenotypic assay. The developed HRM assays identified three participants with normal enzyme activity as heterozygous for G6PD Viangchan. Interestingly, a deletion in intron 5 nucleotide position 637/638 (c.486-34delT) was also detected by the developed HRM assays. G6PD genotyping revealed a total of 12 G6PD genotypes, with a high prevalence of intronic variants. Our results suggested that HRM analysis-based genotyping is a simple and reliable approach for detecting G6PD mutations, and could be used to prevent the misdiagnosis of heterozygous females by phenotypic assay. This study also sheds light on the possibility of overlooking intronic variants, which could affect G6PD expression and contribute to enzyme deficiency.

Survivorship and risk factors for revision of metal-on-metal hip resurfacing.

Aims: Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon. Methods: A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records. Results: A total of 243 hips (205 patients (163 male, 80 female; mean age at surgery 55.3 years (range 25.7 to 75.3)) with MoM-HRA performed between April 2003 and October 2020 were included. Mean follow-up was 11.2 years (range 0.3 to 17.8). Osteoarthritis was the most common indication (93.8%), and 13 hips (5.3%; 7M:6F) showed dysplasia (lateral centre-edge angle < 25°). Acetabular cups were implanted at a median of 45.4° abduction (interquartile range 41.9° - 48.3°) and stems neutral or valgus to the native neck-shaft angle. In all, 11 hips (4.5%; one male, ten females) in ten patients underwent revision surgery at a mean of 7.4 years (range 2.8 to 14.2), giving a cumulative survival rate of 94.8% (95% confidence interval (CI) 91.6% to 98.0%) at ten years, and 93.4% (95% CI 89.3% to 97.6%) at 17 years. For aseptic revision, male survivorship was 100% at 17 years, and 89.6% (95% CI 83.1% to 96.7%) at ten and 17 years for females. Increased metal ion levels were implicated in 50% of female revisions, with the remaining being revised for unexplained pain or avascular necrosis. Conclusion: The Birmingham MoM-HR showed 100% survivorship in males, exceeding the National Institute for Health and Care Excellence '5% at ten years' threshold. Female sex and small component sizes are independent risk factors. Dysplasia alone is not a contraindication to resurfacing.

Escaping the Silos: Utilization of a Pediatric Trauma Escape Room to Promote Interprofessional Education and Collaboration.

BACKGROUND: Millions of children are treated annually for trauma-related injuries but comprise a smaller proportion of emergency department visits than adults. As a result, emergency department teams may not have the knowledge, skills, and confidence to care for pediatric patients, and specialty teams may not interact enough as an interprofessional team to provide high-quality patient care. OBJECTIVE: The purpose of this project is to describe a novel interprofessional simulation-based education initiative to assist pediatric trauma team readiness. METHODS: An escape room was designed to provide an interactive educational environment focused on pediatric trauma education. Using an interprofessional dyad of a trauma nursing specialist and a pediatric nursing expert, the escape room was designed as a series of clues to improve pediatric skills and interprofessional collaboration between specialty teams. The escape room training was conducted (from February to March, 2023) in a large Southeastern U.S. Level II adult trauma center. RESULTS: Twenty-one registered nurses from different specialty teams participated in the simulation exercises with overwhelmingly positive feedback. Colleagues reported this was a unique way to deliver education that resulted in innovative team building and enriched collegiality between the specialty teams. CONCLUSIONS: The escape room educational format was positively received, and future events are planned across disciplines and various topics. Trauma centers with lower pediatric volumes seeking to provide engaging team-based education may use this format as a unique and innovative way to develop teams for clinical success.

The MoXFo initiative - study design: Considerations related to study design and methodology in exercise research for people with multiple sclerosis.

BACKGROUND: Exercise as a subset of physical activity is a cornerstone in the management of multiple sclerosis (MS) based on its pleiotropic effects, but continued progression of the field requires better future designs and methodologies. OBJECTIVES: This paper outlines the work of the 'Study design and methodology' group of the MoXFo (moving exercise research forward) initiative, and addresses critical aspects and future directions when defining the research question of interest, and subsequently, designing the study and exercise intervention in MS patients. METHODS: The work is based on the formation of an international expert panel formed within the MoXFo initiative. We provide a structured and concise synthesis of exercise-specific MS research challenges and considerations when designing randomized controlled trials (RCTs). RESULTS: Challenges and considerations are presented using the Patient population, Intervention, Comparator, Outcomes, Timing, Setting (PICOTS) framework, thereby forming a new and specific MS exercise PICOTS framework. CONCLUSION: We propose that researchers should carefully consider and align all elements of this MS exercise PICOTS framework when developing future research questions and study designs, ultimately improving the quality of new exercise studies in people with MS.

5 year follow up of a hydroxyapatite coated short stem femoral component for hip arthroplasty: a prospective multicentre study.

Short stem, uncemented femoral implants for hip arthroplasty are bone conserving achieving stability through initial metaphyseal press-fit and biological fixation. This study aimed to evaluate the survivorship, mid-term function and health related quality of life outcomes in patients who have undergone total hip arthroplasty (THA) with a fully hydroxyapatite coated straight short stem femoral component with up to 5 years follow-up. 668 patients were recruited to a multicentre study investigating the performance of the cementless Furlong Evolution® stem for THA. 137 patients withdrew at various time points. The mean follow-up was 49 months. Clinical (Harris Hip Score (HHS), radiographic and patient-reported outcome measures-Oxford Hip Score (OHS) and EuroQol 5D (EQ-5D), were recorded pre-operatively and at 6 weeks, 6 months, 1 year, 3 year and 5 year follow ups. At 5-year follow-up, 12 patients underwent revision surgery, representing a cumulative revision rate of 1.8%. Median OHS, HHS and EQ5D scores improved significantly: OHS improved from a pre-operative median of 21 (IQR 14-26) to 47 (IQR 44-48) (p < 0.001). HHS improved from 52 (IQR 40-63) to 98 (IQR 92-100) (p < 0.001) and EQ5D improved from 70 (IQR 50-80) to 85 (IQR 75-95) (p < 0.001). This fully HA-coated straight short femoral stem implant demonstrated acceptable mid-term survivorship and delivered substantial improvements in function and quality of life after THA.

Characterization of a family I inorganic pyrophosphatase from Legionella pneumophila Philadelphia 1.

Inorganic pyrophosphate (PPi) is generated as an intermediate or byproduct of many fundamental metabolic pathways, including DNA/RNA synthesis. The intracellular concentration of PPi must be regulated as buildup can inhibit many critical cellular processes. Inorganic pyrophosphatases (PPases) hydrolyze PPi into two orthophosphates (Pi), preventing the toxic accumulation of the PPi byproduct in cells and making Pi available for use in biosynthetic pathways. Here, the crystal structure of a family I inorganic pyrophosphatase from Legionella pneumophila is reported at 2.0 Šresolution. L. pneumophila PPase (LpPPase) adopts a homohexameric assembly and shares the oligonucleotide/oligosaccharide-binding (OB) ß-barrel core fold common to many other bacterial family I PPases. LpPPase demonstrated hydrolytic activity against a general substrate, with Mg2+ being the preferred metal cofactor for catalysis. Legionnaires' disease is a severe respiratory infection caused primarily by L. pneumophila, and thus increased characterization of the L. pneumophila proteome is of interest.