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1.
Diagnostics (Basel) ; 13(5)2023 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-36900096

RESUMEN

Fever is a common presentation to urgent-care services and is linked to multiple disease processes. To rapidly determine the etiology of fever, improved diagnostic modalities are necessary. This prospective study of 100 hospitalized febrile patients included both positive (FP) and negative (FN) subjects in terms of infection status and 22 healthy controls (HC). We evaluated the performance of a novel PCR-based assay measuring five host mRNA transcripts directly from whole blood to differentiate infectious versus non-infectious febrile syndromes as compared to traditional pathogen-based microbiology results. The FP and FN groups observed a robust network structure with a significant correlation between the five genes. There were statistically significant associations between positive infection status and four of the five genes: IRF-9 (OR = 1.750, 95% CI = 1.16-2.638), ITGAM (OR = 1.533, 95% CI = 1.047-2.244), PSTPIP2 (OR = 2.191, 95% CI = 1.293-3.711), and RUNX1 (OR = 1.974, 95% CI = 1.069-3.646). We developed a classifier model to classify study participants based on these five genes and other variables of interest to assess the discriminatory power of the genes. The classifier model correctly classified more than 80% of the participants into their respective groups, i.e., FP or FN. The GeneXpert prototype holds promise for guiding rapid clinical decision-making, reducing healthcare costs, and improving outcomes in undifferentiated febrile patients presenting for urgent evaluation.

2.
Am J Respir Crit Care Med ; 204(11): 1317-1326, 2021 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-34375564

RESUMEN

Rationale: Standardized dosing of antitubercular drugs contributes to a substantial incidence of toxicities, inadequate treatment response, and relapse, in part due to variable drug concentrations achieved. SNPs in the NAT2 (N-acetyltransferase-2) gene explain the majority of interindividual pharmacokinetic variability of isoniazid (INH). However, an obstacle to implementing pharmacogenomic-guided dosing is the lack of a point-of-care assay. Objectives: To develop and test a NAT2 classification algorithm, validate its performance in predicting isoniazid clearance, and develop a prototype pharmacogenomic assay. Methods: We trained random forest models to predict NAT2 acetylation genotype from unphased SNP data using a global collection of 8,561 phased genomes. We enrolled 48 patients with pulmonary tuberculosis, performed sparse pharmacokinetic sampling, and tested the acetylator prediction algorithm accuracy against estimated INH clearance. We then developed a cartridge-based multiplex quantitative PCR assay on the GeneXpert platform and assessed its analytical sensitivity on whole blood samples from healthy individuals. Measurements and Main Results: With a 5-SNP model trained on two-thirds of the data (n = 5,738), out-of-sample acetylation genotype prediction accuracy on the remaining third (n = 2,823) was 100%. Among the 48 patients with tuberculosis, predicted acetylator types were 27 (56.2%) slow, 16 (33.3%) intermediate, and 5 (10.4%) rapid. INH clearance rates were lowest in predicted slow acetylators (median 14.5 L/h), moderate in intermediate acetylators (median 40.3 L/h), and highest in fast acetylators (median 53.0 L/h). The cartridge-based assay accurately detected all allele patterns directly from 25 µl of whole blood. Conclusions: An automated pharmacogenomic assay on a platform widely used globally for tuberculosis diagnosis could enable personalized dosing of INH.


Asunto(s)
Antituberculosos/farmacocinética , Arilamina N-Acetiltransferasa/genética , Isoniazida/farmacocinética , Pruebas de Farmacogenómica , Polimorfismo Genético/genética , Tuberculosis Pulmonar/genética , Algoritmos , Antituberculosos/administración & dosificación , Estudios de Cohortes , Genotipo , Humanos , Isoniazida/administración & dosificación , Reacción en Cadena de la Polimerasa Multiplex , Farmacogenética , Valor Predictivo de las Pruebas , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/metabolismo
3.
JMIR Res Protoc ; 10(9): e31690, 2021 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-34238753

RESUMEN

BACKGROUND: The current understanding of advanced Parkinson disease (PD) and its treatment is largely based on data from outpatient visits. The most advanced and disabled individuals with PD are disconnected from both care and research. A previous pilot study among older, multimorbid patients with advanced PD demonstrated the feasibility of interdisciplinary home visits to reach the target population, improve care quality, and potentially avoid institutionalization. OBJECTIVE: The aim of this study protocol is to investigate whether interdisciplinary home visits can prevent a decline in quality of life of patients with PD and prevent worsening of caregiver strain. The protocol also explores whether program costs are offset by savings in health care utilization and institutionalization compared with usual care. METHODS: In this single-center, controlled trial, 65 patient-caregiver dyads affected by advanced PD (Hoehn and Yahr stages 3-5 and homebound) are recruited to receive quarterly interdisciplinary home visits over 1 year. The 1-year intervention is delivered by a nurse and a research coordinator, who travel to the home, and it is supported by a movement disorder specialist and social worker (both present by video). Each dyad is compared with age-, sex-, and Hoehn and Yahr stage-matched control dyads drawn from US participants in the longitudinal Parkinson's Outcome Project registry. The primary outcome measure is the change in patient quality of life between baseline and 1 year. Secondary outcome measures include changes in Hoehn and Yahr stage, caregiver strain, self-reported fall frequency, emergency room visits, hospital admissions, and time to institutionalization or death. Intervention costs and changes in health care utilization will be analyzed in a budget impact analysis to explore the potential for model adaptation and dissemination. RESULTS: The protocol was funded in September 2017 and approved by the Rush Institutional Review Board in October 2017. Recruitment began in May 2018 and closed in November 2019 with 65 patient-caregiver dyads enrolled. All study visits have been completed, and analysis is underway. CONCLUSIONS: To our knowledge, this is the first controlled trial to investigate the effects of interdisciplinary home visits among homebound individuals with advanced PD and their caregivers. This study also establishes a unique cohort of patients from whom we can study the natural course of advanced PD, its treatments, and unmet needs. TRIAL REGISTRATION: ClinicalTrials.gov NCT03189459; http://clinicaltrials.gov/ct2/show/NCT03189459. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/31690.

4.
J Endocr Soc ; 5(5): bvab036, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33860132

RESUMEN

CONTEXT: There is no consensus on the effect of recombinant human GH (rhGH) therapy on skeletal maturation in children despite the current practice of annual monitoring of skeletal maturation with bone age in children on rhGH therapy. AIMS: To investigate the effects of long-term rhGH therapy on skeletal age in children and explore the accuracy of bone age-predicted adult height (BAPAH) at different ages based on 13 years of longitudinal data. METHODS: A retrospective longitudinal study of 71 subjects aged 2 to 16 years, mean 9.9 ±â€…3.8 years, treated with rhGH for nonsyndromic short stature for a duration of 2 to 14 years, mean, 5.5 ±â€…2.6 years. Subjects with syndromic short stature and systemic illnesses such as renal failure were excluded. RESULTS: Bone age minus chronological age (BA-CA) did not differ significantly between baseline and the end of rhGH therapy (-1.05 ±â€…1.42 vs -0.69 ±â€…1.63, P = 0.09). Piecewise regression, however, showed a quantifiable catch-up phenomenon in BA of 1.5 months per year of rhGH therapy in the first 6.5 years (P = 0.017) that plateaued thereafter (P = 0.88). BAPAH overestimated near-adult height in younger subjects but became more accurate in older subjects (P < 0.0001). IGF-I levels correlated significantly with increases in child's height and BA-CA. CONCLUSION: Long-term rhGH therapy demonstrated an initial catch-up phenomenon in skeletal maturation in the first 6.5 years that plateaued thereafter with no overall significant advancement in bone age. These findings are reassuring and support strategic, but not the insurance company mandated reflexive annual monitoring of skeletal maturation with bone age in children receiving rhGH therapy.

5.
Eur Urol Oncol ; 4(1): 93-101, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33004290

RESUMEN

BACKGROUND: In patients with haematuria, a fast, noninvasive test with high sensitivity (SN) and negative predictive value (NPV), which is able to detect or exclude bladder cancer (BC), is needed. A newly developed urine assay, Xpert Bladder Cancer Detection (Xpert), measures five mRNA targets (ABL1, CRH, IGF2, UPK1B, and ANXA10) that are frequently overexpressed in BC. OBJECTIVE: To validate the performance of Xpert in patients with haematuria. DESIGN, SETTING, AND PARTICIPANTS: Voided precystoscopy urine specimens were prospectively collected at 22 sites from patients without prior BC undergoing cystoscopy for haematuria. Xpert, cytology, and UroVysion procedures were performed. Technical validation was performed and specificity (SP) was determined in patients without BC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Test characteristics were calculated based on cystoscopy and histology results, and compared between Xpert, cytology, and UroVysion. RESULTS AND LIMITATIONS: We included 828 patients (mean age 64.5 yr, 467 males, 401 never smoked). Xpert had an SN of 78% (95% confidence interval [CI]: 66-87) overall and 90% (95% CI: 76-96) for high-grade (HG) tumours. The NPV was 98% (95% CI: 97-99) overall. The SP was 84% (95% CI: 81-86). In patients with microhaematuria, only one HG patient was missed (NPV 99%). Xpert had higher SN and NPV than cytology and UroVysion. Cytology had the highest SP (97%). In a separate SP study, Xpert had an SP of 89% in patients with benign prostate hypertrophy and 92% in prostate cancer patients. CONCLUSIONS: Xpert is an easy-to-use, noninvasive test with improved SN and NPV compared with cytology and UroVysion, representing a promising tool for identifying haematuric patients with a low likelihood of BC who might not need to undergo cystoscopy. PATIENT SUMMARY: Xpert is an easy-to-perform urine test with good performance compared with standard urine tests. It should help identify (micro)haematuria patients with a very low likelihood to have bladder cancer.


Asunto(s)
ARN Mensajero/análisis , Urinálisis , Neoplasias de la Vejiga Urinaria , Cistoscopía , Femenino , Hematuria/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Vejiga Urinaria/diagnóstico
6.
Case Rep Pediatr ; 2019: 5406482, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31281703

RESUMEN

Lithium-induced nephropathy usually manifests in adulthood as it develops slowly after many years of cumulative exposure. There is very limited information available in pediatric patients. Renal function monitoring and timely intervention is the key in preventing lithium-induced chronic kidney disease in these patients. We report a case of a 14-year-old boy who was on lithium for almost 9 years for his complex psychiatric illness. He presented with increased urinary frequency and nocturia. His serum creatinine increased to 1.15 mg/dL (estimated glomerular filtration rate or eGFR 53 ml/min/1.73 m2) from a baseline of 0.78 mg/dL (eGFR 86 ml/min/1.73 m2) a year prior to this presentation. Results of the imaging study were consistent with lithium-induced nephropathy. He was managed conservatively. His serum creatinine returned to baseline of 0.78 mg/dL after a year of discontinuation of lithium, consistent with mild chronic kidney disease. This case highlights the fact that lithium-induced chronic kidney disease can present in pediatric age group when lithium is initiated at a young age in children and that timely intervention may prevent further progression of renal damage. In addition to drug levels, routine monitoring of renal function during lithium therapy is essential.

7.
Eur Urol ; 75(5): 853-860, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30553612

RESUMEN

BACKGROUND: A fast, noninvasive test with high sensitivity (SN) and a negative predictive value (NPV), which is able to detect recurrences in bladder cancer (BC) patients, is needed. A newly developed urine assay, Xpert Bladder Cancer Monitor (Xpert), measures five mRNA targets (ABL1, CRH, IGF2, UPK1B, and ANXA10) that are frequently overexpressed in BC. OBJECTIVE: To validate Xpert characteristics in patients previously diagnosed with non-muscle-invasive BC. DESIGN, SETTING, AND PARTICIPANTS: Voided precystoscopy urine samples were prospectively collected at 22 sites. Xpert, cytology, and UroVysion were performed. If cystoscopy was suspicious for BC, a histologic examination was performed. Additionally, technical validation was performed and specificity was determined in patients without a history or clinical evidence of BC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Test characteristics were calculated based on cystoscopy and histology results, and compared between Xpert, cytology, and UroVysion. RESULTS AND LIMITATIONS: Of the eligible patients, 239 with a history of BC had results for all assays. The mean age was 71 yr; 190 patients were male, 53 never smoked, and 64% had previous intravesical immunotherapy (35%) or chemotherapy (29%). Forty-three cases of recurrences occurred. Xpert had overall SN of 74% (95% confidence interval [CI]: 60-85) and 83% (95% CI: 64-93) for high-grade (HG) tumors. The NPV was 93% (95% CI: 89-96) overall and 98% (95% CI: 94-99) for HG tumors. Specificity was 80% (95% CI: 73-85). Xpert SN and NPV were superior to those of cytology and UroVysion. Specificity in non-BC individuals (n=508) was 95% (95% CI: 93-97). CONCLUSIONS: Xpert has an improved NPV compared with UroVysion and cytology in patients under follow-up for BC. It represents a promising tool for excluding BC in these patients, reducing the need for cystoscopy. PATIENT SUMMARY: Xpert is an easy-to-perform urine test with good performance compared with standard urine tests. It should help optimize the follow-up of recurrent bladder cancer patients.


Asunto(s)
Recurrencia Local de Neoplasia/diagnóstico , Recurrencia Local de Neoplasia/orina , Vigilancia de la Población/métodos , ARN Mensajero/orina , Neoplasias de la Vejiga Urinaria/orina , Adulto , Anciano , Anciano de 80 o más Años , Anexinas/genética , Biopsia , Hormona Liberadora de Corticotropina/genética , Cistoscopía , Femenino , Humanos , Factor II del Crecimiento Similar a la Insulina/genética , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/genética , Valor Predictivo de las Pruebas , Estudios Prospectivos , Proteínas Proto-Oncogénicas c-abl/genética , Urinálisis , Vejiga Urinaria/patología , Neoplasias de la Vejiga Urinaria/genética , Uroplaquina Ib/genética , Adulto Joven
8.
J Urol ; 199(3): 655-662, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29061538

RESUMEN

PURPOSE: Despite suboptimal sensitivity urine cytology is often performed as an adjunct to cystoscopy for bladder cancer diagnosis. We aimed to develop a noninvasive, fast molecular diagnostic test for bladder cancer detection with better sensitivity than urine cytology while maintaining adequate specificity. MATERIALS AND METHODS: Urine specimens were collected at 18 multinational sites from subjects prior to cystoscopy or tumor resection, and from healthy and other control subjects without evidence of bladder cancer. The levels of 10 urinary mRNAs were measured in a training cohort of 483 subjects and regression analysis was used to identify a 5-mRNA model to predict cancer status. The performance of the GeneXpert® Bladder Cancer Assay, an assay labeled for investigational use only to detect the 5 mRNAs ABL1, CRH, IGF2, ANXA10 and UPK1B, was evaluated in an independent test cohort of 450 participants. RESULTS: In the independent test cohort the assay ROC curve AUC was 0.87 (95% CI 0.81-0.92). At an example cutoff point of 0.4 overall sensitivity was 73% while specificity was 90% and 77% in the hematuria and surveillance patient populations, respectively. CONCLUSIONS: We developed a 90-minute, urine based test that is simple to perform for the detection of bladder cancer. The test can help guide physician decision making in the management of bladder cancer. Additional evaluation in a prospective study is needed to establish the clinical usefulness of this assay.


Asunto(s)
Carcinoma de Células Transicionales/orina , Cistoscopía/métodos , ARN Neoplásico/orina , Neoplasias de la Vejiga Urinaria/orina , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/orina , Carcinoma de Células Transicionales/diagnóstico , Carcinoma de Células Transicionales/genética , Femenino , Estudios de Seguimiento , Marcadores Genéticos/genética , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Curva ROC , Reacción en Cadena en Tiempo Real de la Polimerasa , Factores de Tiempo , Neoplasias de la Vejiga Urinaria/diagnóstico , Neoplasias de la Vejiga Urinaria/genética , Adulto Joven
9.
Biomol NMR Assign ; 11(1): 51-56, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-27981424

RESUMEN

The Bas-Congo virus (BASV) is the first rhabdovirus associated with a human outbreak of acute hemorrhagic fever. The single-stranded, negative-sense RNA genome of BASV contains the five core genes present in all rhabdoviral genomes plus an additional three genes, annotated U1, U2, and U3, with weak (<21%) sequence similarity only to a handful of genes observed in a few other rhabdoviral genomes. The function of the rhabdoviral U proteins is unknown, but, they are hypothesized to play a role in viral infection or replication. To better understand this unique family of proteins, a construct containing residues 27-203 of the 216-residue U1 protein (BASV-U1*) was prepared. By collecting data in 0.5 M urea it was possible to eliminate transient association enough to enable the assignment of most of the observable 1HN, 1Hα, 15N, 13Cα, 13Cß, and 13C´ chemical shifts for BASV-U1* that will provide a foundation to study its solution properties. The analyses of these chemical shifts along with 15N-edited NOESY data enabled the identification of the elements of secondary structure present in BASV-U1*.


Asunto(s)
Resonancia Magnética Nuclear Biomolecular , Rhabdoviridae , Proteínas Virales/química , Estructura Secundaria de Proteína , Proteínas Virales/metabolismo
10.
Lancet Oncol ; 17(11): 1569-1578, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27646843

RESUMEN

BACKGROUND: Histone deacetylase (HDAC) inhibitors are an important new class of therapeutics for treating multiple myeloma. Ricolinostat (ACY-1215) is the first oral selective HDAC6 inhibitor with reduced class I HDAC activity to be studied clinically. Motivated by findings from preclinical studies showing potent synergistic activity with ricolinostat and lenalidomide, our goal was to assess the safety and preliminary activity of the combination of ricolinostat with lenalidomide and dexamethasone in relapsed or refractory multiple myeloma. METHODS: In this multicentre phase 1b trial, we recruited patients aged 18 years or older with previously treated relapsed or refractory multiple myeloma from five cancer centres in the USA. Inclusion criteria included a Karnofsky Performance Status score of at least 70, measureable disease, adequate bone marrow reserve, adequate hepatic function, and a creatinine clearance of at least 50 mL per min. Exclusion criteria included previous exposure to HDAC inhibitors; previous allogeneic stem-cell transplantation; previous autologous stem-cell transplantation within 12 weeks of baseline; active systemic infection; malignancy within the last 5 years; known or suspected HIV, hepatitis B, or hepatitis C infection; a QTc Fridericia of more than 480 ms; and substantial cardiovascular, gastrointestinal, psychiatric, or other medical disorders. We gave escalating doses (from 40-240 mg once daily to 160 mg twice daily) of oral ricolinostat according to a standard 3 + 3 design according to three different regimens on days 1-21 with a conventional 28 day schedule of oral lenalidomide (from 15 mg [in one cohort] to 25 mg [in all other cohorts] once daily) and oral dexamethasone (40 mg weekly). Primary outcomes were dose-limiting toxicities, the maximum tolerated dose of ricolinostat in this combination, and the dose and schedule of ricolinostat recommended for further phase 2 investigation. Secondary outcomes were the pharmacokinetics and pharmacodynamics of ricolinostat in this combination and the preliminary anti-tumour activity of this treatment. The trial is closed to accrual and is registered at ClinicalTrials.gov, number NCT01583283. FINDINGS: Between July 12, 2012, and Aug 20, 2015, we enrolled 38 patients. We observed two dose-limiting toxicities with ricolinostat 160 mg twice daily: one (2%) grade 3 syncope and one (2%) grade 3 myalgia event in different cohorts. A maximum tolerated dose was not reached. We chose ricolinostat 160 mg once daily on days 1-21 of a 28 day cycle as the recommended dose for future phase 2 studies in combination with lenalidomide 25 mg and dexamethasone 40 mg. The most common adverse events were fatigue (grade 1-2 in 14 [37%] patients; grade 3 in seven [18%]) and diarrhoea (grade 1-2 in 15 [39%] patients; grade 3 in two [5%]). Our pharmacodynamic studies showed that at clinically relevant doses, ricolinostat selectively inhibits HDAC6 while retaining a low and tolerable level of class I HDAC inhibition. The pharmacokinetics of ricolinostat and lenalidomide were not affected by co-administration. In a preliminary assessment of antitumour activity, 21 (55% [95% CI 38-71]) of 38 patients had an overall response. INTERPRETATION: The findings from this study provide preliminary evidence that ricolinostat is a safe and well tolerated selective HDAC6 inhibitor, which might partner well with lenalidomide and dexamethasone to enhance their efficacy in relapsed or refractory multiple myeloma. FUNDING: Acetylon Pharmaceuticals.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Mieloma Múltiple/tratamiento farmacológico , Anciano , Dexametasona/administración & dosificación , Dexametasona/efectos adversos , Femenino , Inhibidores de Histona Desacetilasas/administración & dosificación , Humanos , Ácidos Hidroxámicos/administración & dosificación , Ácidos Hidroxámicos/efectos adversos , Lenalidomida , Masculino , Persona de Mediana Edad , Mieloma Múltiple/mortalidad , Pirimidinas/administración & dosificación , Pirimidinas/efectos adversos , Talidomida/administración & dosificación , Talidomida/efectos adversos , Talidomida/análogos & derivados
11.
PLoS One ; 10(4): e0125010, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25909780

RESUMEN

Crystallization of a maltose-binding protein MCL1 fusion has yielded a robust crystallography platform that generated the first apo MCL1 crystal structure, as well as five ligand-bound structures. The ability to obtain fragment-bound structures advances structure-based drug design efforts that, despite considerable effort, had previously been intractable by crystallography. In the ligand-independent crystal form we identify inhibitor binding modes not observed in earlier crystallographic systems. This MBP-MCL1 construct dramatically improves the structural understanding of well-validated MCL1 ligands, and will likely catalyze the structure-based optimization of high affinity MCL1 inhibitors.


Asunto(s)
Proteínas de Unión a Maltosa/química , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/química , Apoproteínas/química , Apoproteínas/genética , Cristalización , Cristalografía por Rayos X , Diseño de Fármacos , Humanos , Ligandos , Proteínas de Unión a Maltosa/genética , Modelos Moleculares , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/antagonistas & inhibidores , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/genética , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Unión Proteica , Conformación Proteica , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética
12.
PLoS One ; 6(8): e24488, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21909395

RESUMEN

The crystallization of membrane proteins in amphiphile-rich materials such as lipidic cubic phases is an established methodology in many structural biology laboratories. The standard procedure employed with this methodology requires the generation of a highly viscous lipidic material by mixing lipid, for instance monoolein, with a solution of the detergent solubilized membrane protein. This preparation is often carried out with specialized mixing tools that allow handling of the highly viscous materials while minimizing dead volume to save precious membrane protein sample. The processes that occur during the initial mixing of the lipid with the membrane protein are not well understood. Here we show that the formation of the lipidic phases and the incorporation of the membrane protein into such materials can be separated experimentally. Specifically, we have investigated the effect of different initial monoolein-based lipid phase states on the crystallization behavior of the colored photosynthetic reaction center from Rhodobacter sphaeroides. We find that the detergent solubilized photosynthetic reaction center spontaneously inserts into and concentrates in the lipid matrix without any mixing, and that the initial lipid material phase state is irrelevant for productive crystallization. A substantial in-situ enrichment of the membrane protein to concentration levels that are otherwise unobtainable occurs in a thin layer on the surface of the lipidic material. These results have important practical applications and hence we suggest a simplified protocol for membrane protein crystallization within amphiphile rich materials, eliminating any specialized mixing tools to prepare crystallization experiments within lipidic cubic phases. Furthermore, by virtue of sampling a membrane protein concentration gradient within a single crystallization experiment, this crystallization technique is more robust and increases the efficiency of identifying productive crystallization parameters. Finally, we provide a model that explains the incorporation of the membrane protein from solution into the lipid phase via a portal lamellar phase.


Asunto(s)
Cristalización/métodos , Glicéridos/química , Lípidos/química , Proteínas de la Membrana/química , Rhodobacter sphaeroides/química , Modelos Biológicos , Proteínas del Complejo del Centro de Reacción Fotosintética/química , Factores de Tiempo
13.
J Clin Microbiol ; 48(1): 229-37, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19864480

RESUMEN

Current nucleic acid amplification methods to detect Mycobacterium tuberculosis are complex, labor-intensive, and technically challenging. We developed and performed the first analysis of the Cepheid Gene Xpert System's MTB/RIF assay, an integrated hands-free sputum-processing and real-time PCR system with rapid on-demand, near-patient technology, to simultaneously detect M. tuberculosis and rifampin resistance. Analytic tests of M. tuberculosis DNA demonstrated a limit of detection (LOD) of 4.5 genomes per reaction. Studies using sputum spiked with known numbers of M. tuberculosis CFU predicted a clinical LOD of 131 CFU/ml. Killing studies showed that the assay's buffer decreased M. tuberculosis viability by at least 8 logs, substantially reducing biohazards. Tests of 23 different commonly occurring rifampin resistance mutations demonstrated that all 23 (100%) would be identified as rifampin resistant. An analysis of 20 nontuberculosis mycobacteria species confirmed high assay specificity. A small clinical validation study of 107 clinical sputum samples from suspected tuberculosis cases in Vietnam detected 29/29 (100%) smear-positive culture-positive cases and 33/39 (84.6%) or 38/53 (71.7%) smear-negative culture-positive cases, as determined by growth on solid medium or on both solid and liquid media, respectively. M. tuberculosis was not detected in 25/25 (100%) of the culture-negative samples. A study of 64 smear-positive culture-positive sputa from retreatment tuberculosis cases in Uganda detected 63/64 (98.4%) culture-positive cases and 9/9 (100%) cases of rifampin resistance. Rifampin resistance was excluded in 54/55 (98.2%) susceptible cases. Specificity rose to 100% after correcting for a conventional susceptibility test error. In conclusion, this highly sensitive and simple-to-use system can detect M. tuberculosis directly from sputum in less than 2 h.


Asunto(s)
Antituberculosos/farmacología , Técnicas Bacteriológicas/métodos , Farmacorresistencia Bacteriana , Mycobacterium tuberculosis/efectos de los fármacos , Sistemas de Atención de Punto , Rifampin/farmacología , Tuberculosis/diagnóstico , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Sensibilidad y Especificidad , Esputo/microbiología , Tuberculosis/microbiología , Uganda , Vietnam , Adulto Joven
14.
Acta Crystallogr D Biol Crystallogr ; 65(Pt 10): 1062-73, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19770503

RESUMEN

When starting a protein-crystallization project, scientists are faced with several unknowns. Amongst them are these questions: (i) is the purity of the starting material sufficient? and (ii) which type of crystallization experiment is the most promising to conduct? The difficulty in purifying active membrane-protein samples for crystallization trials and the high costs associated with producing such samples require an extremely pragmatic approach. Additionally, practical guidelines are needed to increase the efficiency of membrane-protein crystallization. In order to address these conundrums, the effects of commonly encountered impurities on various membrane-protein crystallization regimes have been investigated and it was found that the lipidic cubic phase (LCP) based crystallization methodology is more robust than crystallization in detergent environments using vapor diffusion or microbatch approaches in its ability to tolerate contamination in the forms of protein, lipid or other general membrane components. LCP-based crystallizations produced crystals of the photosynthetic reaction center (RC) of Rhodobacter sphaeroides from samples with substantial levels of residual impurities. Crystals were obtained with protein contamination levels of up to 50% and the addition of lipid material and membrane fragments to pure samples of RC had little effect on the number or on the quality of crystals obtained in LCP-based crystallization screens. If generally applicable, this tolerance for impurities may avoid the need for samples of ultrahigh purity when undertaking initial crystallization screening trials to determine preliminary crystallization conditions that can be optimized for a given target protein.


Asunto(s)
Cristalización/métodos , Proteínas de la Membrana/química , Proteínas Bacterianas/química , Proteínas Bacterianas/aislamiento & purificación , Lípidos/química , Proteínas de la Membrana/aislamiento & purificación , Rhodobacter sphaeroides/química
15.
BMC Biotechnol ; 9: 36, 2009 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-19383142

RESUMEN

BACKGROUND: To improve efficiency in high throughput protein structure determination, we have developed a database software package, Gene Composer, which facilitates the information-rich design of protein constructs and their codon engineered synthetic gene sequences. With its modular workflow design and numerous graphical user interfaces, Gene Composer enables researchers to perform all common bio-informatics steps used in modern structure guided protein engineering and synthetic gene engineering. RESULTS: An interactive Alignment Viewer allows the researcher to simultaneously visualize sequence conservation in the context of known protein secondary structure, ligand contacts, water contacts, crystal contacts, B-factors, solvent accessible area, residue property type and several other useful property views. The Construct Design Module enables the facile design of novel protein constructs with altered N- and C-termini, internal insertions or deletions, point mutations, and desired affinity tags. The modifications can be combined and permuted into multiple protein constructs, and then virtually cloned in silico into defined expression vectors. The Gene Design Module uses a protein-to-gene algorithm that automates the back-translation of a protein amino acid sequence into a codon engineered nucleic acid gene sequence according to a selected codon usage table with minimal codon usage threshold, defined G:C% content, and desired sequence features achieved through synonymous codon selection that is optimized for the intended expression system. The gene-to-oligo algorithm of the Gene Design Module plans out all of the required overlapping oligonucleotides and mutagenic primers needed to synthesize the desired gene constructs by PCR, and for physically cloning them into selected vectors by the most popular subcloning strategies. CONCLUSION: We present a complete description of Gene Composer functionality, and an efficient PCR-based synthetic gene assembly procedure with mis-match specific endonuclease error correction in combination with PIPE cloning. In a sister manuscript we present data on how Gene Composer designed genes and protein constructs can result in improved protein production for structural studies.


Asunto(s)
Bases de Datos Genéticas , Ingeniería de Proteínas/métodos , Programas Informáticos , Interfaz Usuario-Computador , Algoritmos , Clonación Molecular , Codón , Biología Computacional , Genes Sintéticos , Alineación de Secuencia
16.
BMC Biotechnol ; 9: 37, 2009 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-19383143

RESUMEN

BACKGROUND: With the goal of improving yield and success rates of heterologous protein production for structural studies we have developed the database and algorithm software package Gene Composer. This freely available electronic tool facilitates the information-rich design of protein constructs and their engineered synthetic gene sequences, as detailed in the accompanying manuscript. RESULTS: In this report, we compare heterologous protein expression levels from native sequences to that of codon engineered synthetic gene constructs designed by Gene Composer. A test set of proteins including a human kinase (P38alpha), viral polymerase (HCV NS5B), and bacterial structural protein (FtsZ) were expressed in both E. coli and a cell-free wheat germ translation system. We also compare the protein expression levels in E. coli for a set of 11 different proteins with greatly varied G:C content and codon bias. CONCLUSION: The results consistently demonstrate that protein yields from codon engineered Gene Composer designs are as good as or better than those achieved from the synonymous native genes. Moreover, structure guided N- and C-terminal deletion constructs designed with the aid of Gene Composer can lead to greater success in gene to structure work as exemplified by the X-ray crystallographic structure determination of FtsZ from Bacillus subtilis. These results validate the Gene Composer algorithms, and suggest that using a combination of synthetic gene and protein construct engineering tools can improve the economics of gene to structure research.


Asunto(s)
Ingeniería de Proteínas/métodos , Programas Informáticos , Interfaz Usuario-Computador , Algoritmos , Composición de Base , Sistema Libre de Células , Codón , Escherichia coli/metabolismo , Expresión Génica , Genes Sintéticos , Humanos , Estructura Terciaria de Proteína , Alineación de Secuencia
17.
Can Fam Physician ; 49: 1626-31, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14708928

RESUMEN

OBJECTIVE: Much of what we know about ethical issues in palliative care comes from the perceptions of physicians and ethicists. In this study our goal was to hear other voices and to gain first-hand knowledge of the possibly contrasting views of patients, their families, nurses, volunteers, and other team members on end-of-life issues. DESIGN: Qualitative study using semistructured interviews. SETTING: Inpatient and consultation palliative care service of the Royal Victoria Hospital in Montreal, Que. PARTICIPANTS: Of 113 people interviewed, 13 were patients, 43 were family members, 32 were volunteers, 14 were nurses, and 11 were other staff. METHOD: Interviewers elicited subjects' perspectives on ethical issues. Content analysis was used to identify, code, and categorize themes in the data. MAIN FINDINGS: Communication difficulties and insufficient resources and staff were the most frequently mentioned problems in this palliative care setting. CONCLUSION: The findings of this study will help guide policy decisions and setting of educational priorities in end-of-life care, particularly regarding the importance of adequate communication.


Asunto(s)
Salud de la Familia , Enfermeras y Enfermeros , Cuidados Paliativos/ética , Relaciones Profesional-Paciente , Comunicación , Encuestas de Atención de la Salud , Política de Salud , Humanos , Formulación de Políticas , Cuidado Terminal/ética
18.
Phys Sportsmed ; 7(10): 127-130, 1979 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29267068

RESUMEN

Education and prevention across the whole spectrum of sportsmedicine are the goals of Cleveland's nine-year-old Rainbow Sports Medicine Center.

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