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1.
Antimicrob Agents Chemother ; 67(2): e0137722, 2023 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-36715507

RESUMO

Gram-negative bacteria are notoriously more resistant to antibiotics than Gram-positive bacteria, primarily due to the presence of the outer membrane and a plethora of active efflux pumps. However, the potency of antibiotics also varies dramatically between different Gram-negative pathogens, suggesting major mechanistic differences in how antibiotics penetrate permeability barriers. Two approaches are used broadly to analyze how permeability barriers affect intracellular accumulation of antibiotics. One compares the antibacterial activities of compounds, while the other measures the total intracellular concentrations of compounds in nongrowing cells, with both approaches using strains harboring wild-type or genetically modified efflux systems and permeability barriers. Whether the two assays provide similar mechanistic insights remains unclear. In this study, we analyzed the intracellular accumulation and antibacterial activities of antibiotics representative of major clinical classes in three Gram-negative pathogens of high clinical importance, Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. We found that both assays are informative about properties of permeability barriers, but there is no quantitative agreement between the assays. Our results show that the three pathogens differ dramatically in their permeability barriers, with the outer membrane playing the dominant role in E. coli and P. aeruginosa but efflux dominating in A. baumannii. However, even compounds of the same chemotype may use different permeation pathways depending on small chemical modifications. Accordingly, a classification analysis revealed limited conservation of molecular properties that define compound penetration into the three bacteria.


Assuntos
Antibacterianos , Escherichia coli , Antibacterianos/química , Escherichia coli/genética , Escherichia coli/metabolismo , Transporte Biológico , Bactérias Gram-Negativas/metabolismo , Permeabilidade , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/metabolismo
2.
Osteoporos Int ; 34(1): 147-160, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36342539

RESUMO

Patients with Duchenne muscular dystrophy (DMD) have a high fracture burden due to progressive myopathy and steroid-induced osteoporosis. This study in males with DMD showed that markers of systemic glucocorticoid exposure including shorter stature, greater bone age delay, and lower lumbar spine bone mineral density were associated with spine fragility. INTRODUCTION: Fragility  fractures are frequent in DMD. The purpose of this study was to identify clinical factors associated with prevalent vertebral fractures (VF) in boys, teens/young adults with Duchenne muscular dystrophy (DMD). METHODS: This was a cross-sectional study of males aged 4-25 years with DMD. VF were evaluated using the modified Genant semi-quantitative method on T4-L4 lateral spine radiographs. Areal bone mineral density (aBMD) was measured at the lumbar spine (LS) and used to estimate volumetric BMD (vBMD). Clinical factors were analyzed for their association with the Spinal Deformity Index (SDI, the sum of the Genant grades). RESULTS: Sixty participants were enrolled (mean age 11.5 years, range 5.4-19.5). Nineteen participants (32%) had a total of 67 VF; 23/67 VF (34%) were moderate or severe. Participants with VF were shorter (mean height Z-score ± standard deviation: - 3.1 ± 1.4 vs. - 1.8 ± 1.4, p = 0.001), had longer glucocorticoid exposure (mean duration 6.0 ± 3.3 vs. 3.9 ± 3.3 years, p = 0.027), greater bone age (BA) delay (mean BA to chronological age difference - 3.2 ± 3.4 vs. - 1.3 ± 1.2 years, p = 0.035), and lower LSaBMD Z-scores (mean - 3.0 ± 1.0 vs. - 2.2 ± 1.2, p = 0.023). There was no difference in LSvBMD Z-scores. Multivariable Poisson regression showed that every 0.1 mg/kg/day increment in average glucocorticoid daily dose was associated with a 1.4-fold SDI increase (95% confidence interval: 1.1-1.7, p = 0.013). Greater BA delay (p < 0.001), higher weight Z-score (p = 0.004), decreased height Z-score (p = 0.025), and lower LSvBMD Z-score (p = 0.025) were also associated with SDI increase. CONCLUSION: Readily measurable clinical variables were associated with prevalent VF in males with glucocorticoid-treated DMD. These variables may be useful to identify candidates for primary osteoporosis prevention after glucocorticoid initiation.


Assuntos
Fraturas Ósseas , Distrofia Muscular de Duchenne , Osteoporose , Fraturas da Coluna Vertebral , Masculino , Adolescente , Humanos , Pré-Escolar , Criança , Adulto Jovem , Adulto , Glucocorticoides/efeitos adversos , Distrofia Muscular de Duchenne/complicações , Distrofia Muscular de Duchenne/tratamento farmacológico , Estudos Transversais , Fraturas da Coluna Vertebral/etiologia , Fraturas da Coluna Vertebral/complicações , Fraturas Ósseas/complicações , Osteoporose/etiologia , Osteoporose/induzido quimicamente , Densidade Óssea , Fatores de Risco , Vértebras Lombares
3.
Calcif Tissue Int ; 112(5): 613-620, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36867194

RESUMO

Osteogenesis imperfecta (OI) type VI, a recessively inherited form of OI caused by mutations in SERPINF1, is a severe form distinguished by osteomalacia on bone histomorphometry. We describe a boy with severe OI type VI who was initially treated with intravenous (IV) zoledronic acid (ZA) at 1.4 years of age; however, a year later he transitioned to denosumab 1 mg/kg sub-cutaneously every three months in an effort to decrease fracture rates. After two years on denosumab, he presented with symptomatic hypercalcemia due to the denosumab-induced, hyper-resorptive rebound phenomenon. Laboratory parameters at the time of the rebound were as follows: elevated serum ionized calcium (1.62 mmol/L, N 1.16-1.36), elevated serum creatinine due to hypercalcemia-induced muscle catabolism (83 µmol/L, N 9-55), and suppressed parathyroid hormone (PTH) (< 0.7 pmol/L, N 1.3-5.8). The hypercalcemia was responsive to low-dose IV pamidronate, with a rapid decline in serum ionized calcium, and otherwise normalization of the aforementioned parameters within 10 days. To benefit from the powerful, albeit short-term, anti-resorptive effect of denosumab without further rebound episodes, he was treated thereafter with denosumab 1 mg/kg alternating every three months with IV ZA 0.025 mg/kg. Five years later, he remained on dual alternating anti-resorptive therapy without further rebound episodes, and an overall improvement in his clinical status. This novel pharmacological approach of alternating short- and long-term anti-resorptive therapy every three months has not previously been described. Our report suggests this strategy may be an effective method for prevention of the rebound phenomenon in select children for whom denosumab may be beneficial.


Assuntos
Conservadores da Densidade Óssea , Hipercalcemia , Osteogênese Imperfeita , Criança , Masculino , Humanos , Osteogênese Imperfeita/tratamento farmacológico , Osteogênese Imperfeita/genética , Denosumab , Hipercalcemia/tratamento farmacológico , Cálcio/farmacologia , Densidade Óssea , Ácido Zoledrônico/uso terapêutico
4.
Cell ; 135(3): 412-4, 2008 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-18984152

RESUMO

In bacteria, archaea, and the eukaryote nucleus, the endonuclease ribonuclease P (RNase P) is composed of a catalytic RNA that is assisted by protein subunits. Holzmann et al. (2008) now provide evidence that the human mitochondrial RNase P is an entirely protein-based enzyme.


Assuntos
Mitocôndrias/enzimologia , RNA Catalítico/análise , Ribonuclease P/química , Evolução Molecular , Humanos , Ribonuclease P/metabolismo
5.
Adv Exp Med Biol ; 1397: 1-19, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36522590

RESUMO

The undergraduate medical programme at Newcastle University (NU) includes a fundamental 'Essentials of Medical Practice' (EOMP) phase comprising the first 2 years of study. This period is designed to support entrants in their transition from further education into the advanced study and practice of clinical medicine. The anatomical sciences of gross anatomy, histology and embryology, and life sciences including physiology, pharmacology and genetics are key disciplines taught within the integrated case-based EOMP curriculum. Learners apply basic science knowledge to clinical scenarios during training in practical examination, communication and reasoning skills. Within the modern pedagogic landscape, the development and introduction of technology-enhanced learning strategies have enhanced the provision of remote learning resources in pre-clinical education. However, the emergence of COVID-19 has resulted in widespread technological challenges for educators and learners, and has raised pedagogic, logistical and ethical concerns. Nonetheless, the pandemic has produced favourable conditions for the creation of valuable digital visualisation strategies for learning and teaching, and for developing and modernising universal approaches to remote education. Here, we describe our technology-enhanced adaptations to COVID-19 across the domains of teaching, learning and academic support for pre-clinical learners studying basic life sciences and clinical skills. Moreover, we outline research-informed digital visualisation solutions to pandemic-era challenges and reflect upon experiences gained within our own educational context. In doing so, we provide insights into the impacts and successes of our interventions. While providing a record of unprecedented contemporary circumstances, we also aim to utilise our observations and experiences of COVID-19 pedagogy when developing ongoing strategies for delivering curricula and futureproofing educational practice.


Assuntos
COVID-19 , Educação de Graduação em Medicina , Humanos , Pandemias , COVID-19/epidemiologia , Currículo , Educação de Graduação em Medicina/métodos , Aprendizagem
6.
Nucleic Acids Res ; 48(10): 5366-5382, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32324216

RESUMO

Resistance to androgen receptor (AR) targeting therapeutics in prostate cancer (PC) is a significant clinical problem. Mechanisms by which this is accomplished include AR amplification and expression of AR splice variants, demonstrating that AR remains a key therapeutic target in advanced disease. For the first time we show that IKBKE drives AR signalling in advanced PC. Significant inhibition of AR regulated gene expression was observed upon siRNA-mediated IKBKE depletion or pharmacological inhibition due to inhibited AR gene expression in multiple cell line models including a LNCaP derivative cell line resistant to the anti-androgen, enzalutamide (LNCaP-EnzR). Phenotypically, this resulted in significant inhibition of proliferation, migration and colony forming ability suggesting that targeting IKBKE could circumvent resistance to AR targeting therapies. Indeed, pharmacological inhibition in the CWR22Rv1 xenograft mouse model reduced tumour size and enhanced survival. Critically, this was validated in patient-derived explants where enzymatic inactivation of IKBKE reduced cell proliferation and AR expression. Mechanistically, we provide evidence that IKBKE regulates AR levels via Hippo pathway inhibition to reduce c-MYC levels at cis-regulatory elements within the AR gene. Thus, IKBKE is a therapeutic target in advanced PC suggesting repurposing of clinically tested IKBKE inhibitors could be beneficial to castrate resistant PC patients.


Assuntos
Quinase I-kappa B/fisiologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Receptores Androgênicos/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Via de Sinalização Hippo , Humanos , Quinase I-kappa B/antagonistas & inibidores , Masculino , Camundongos Nus , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/patologia , Receptores Androgênicos/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Transcrição Gênica , Proteínas de Sinalização YAP
7.
Proc Natl Acad Sci U S A ; 116(43): 21748-21757, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31591200

RESUMO

The development of new antimicrobial drugs is a priority to combat the increasing spread of multidrug-resistant bacteria. This development is especially problematic in gram-negative bacteria due to the outer membrane (OM) permeability barrier and multidrug efflux pumps. Therefore, we screened for compounds that target essential, nonredundant, surface-exposed processes in gram-negative bacteria. We identified a compound, MRL-494, that inhibits assembly of OM proteins (OMPs) by the ß-barrel assembly machine (BAM complex). The BAM complex contains one essential surface-exposed protein, BamA. We constructed a bamA mutagenesis library, screened for resistance to MRL-494, and identified the mutation bamAE470K BamAE470K restores OMP biogenesis in the presence of MRL-494. The mutant protein has both altered conformation and activity, suggesting it could either inhibit MRL-494 binding or allow BamA to function in the presence of MRL-494. By cellular thermal shift assay (CETSA), we determined that MRL-494 stabilizes BamA and BamAE470K from thermally induced aggregation, indicating direct or proximal binding to both BamA and BamAE470K Thus, it is the altered activity of BamAE470K responsible for resistance to MRL-494. Strikingly, MRL-494 possesses a second mechanism of action that kills gram-positive organisms. In microbes lacking an OM, MRL-494 lethally disrupts the cytoplasmic membrane. We suggest that the compound cannot disrupt the cytoplasmic membrane of gram-negative bacteria because it cannot penetrate the OM. Instead, MRL-494 inhibits OMP biogenesis from outside the OM by targeting BamA. The identification of a small molecule that inhibits OMP biogenesis at the cell surface represents a distinct class of antibacterial agents.


Assuntos
Antibacterianos/farmacologia , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Escherichia coli/antagonistas & inibidores , Escherichia coli/efeitos dos fármacos , Multimerização Proteica/efeitos dos fármacos , Triazinas/farmacologia , Proteínas da Membrana Bacteriana Externa/antagonistas & inibidores , Proteínas da Membrana Bacteriana Externa/genética , Transporte Biológico/fisiologia , Membrana Celular/efeitos dos fármacos , Permeabilidade da Membrana Celular/fisiologia , Avaliação Pré-Clínica de Medicamentos , Farmacorresistência Bacteriana/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Testes de Sensibilidade Microbiana
8.
J Foot Ankle Surg ; 61(4): 680-685, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35562304

RESUMO

Magnetic resonance imaging (MRI) is commonly used to evaluate soft tissue pathology of the foot and ankle. Prior investigations have reported limitations of this modality, however, in evaluation of pathologies related to the peroneal tendons. This article investigates the correlation of pre-operative MRI studies with intraoperative findings. Five board-certified radiologists interpreted MRIs of 80 ankles that subsequently underwent surgical procedures performed by one board-certified foot and ankle surgeon, after which comparison was made between their findings. Statistically significant disagreement was found between radiologist and surgeon findings of a normal peroneus brevis (PB), PB and peroneus longus (PL) tendinosis, PB and PL hypertrophy, PB and PL partial linear tears, PB and PL flattening, PB longitudinal split tears, and the PB attritional spectrum (combined analysis of flattening, partial linear tearing, and longitudinal split tears). These results suggest that given the disconcordance between MRI and intraoperative findings, surgeons should remain cautious in their reliance upon this imaging modality when evaluating this anatomic region.


Assuntos
Traumatismos dos Tendões , Articulação do Tornozelo , Humanos , Imageamento por Ressonância Magnética/métodos , Estudos Retrospectivos , Ruptura , Traumatismos dos Tendões/diagnóstico por imagem , Traumatismos dos Tendões/patologia , Traumatismos dos Tendões/cirurgia , Tendões/cirurgia
9.
Nature ; 526(7575): 672-7, 2015 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-26416753

RESUMO

Riboswitches are non-coding RNA structures located in messenger RNAs that bind endogenous ligands, such as a specific metabolite or ion, to regulate gene expression. As such, riboswitches serve as a novel, yet largely unexploited, class of emerging drug targets. Demonstrating this potential, however, has proven difficult and is restricted to structurally similar antimetabolites and semi-synthetic analogues of their cognate ligand, thus greatly restricting the chemical space and selectivity sought for such inhibitors. Here we report the discovery and characterization of ribocil, a highly selective chemical modulator of bacterial riboflavin riboswitches, which was identified in a phenotypic screen and acts as a structurally distinct synthetic mimic of the natural ligand, flavin mononucleotide, to repress riboswitch-mediated ribB gene expression and inhibit bacterial cell growth. Our findings indicate that non-coding RNA structural elements may be more broadly targeted by synthetic small molecules than previously expected.


Assuntos
Pirimidinas/química , Pirimidinas/farmacologia , RNA Bacteriano/química , RNA Bacteriano/efeitos dos fármacos , Riboswitch/efeitos dos fármacos , Animais , Aptâmeros de Nucleotídeos/química , Bactérias/citologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Sequência de Bases , Cristalografia por Raios X , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Feminino , Mononucleotídeo de Flavina/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Transferases Intramoleculares/genética , Ligantes , Camundongos , Camundongos Endogâmicos DBA , Modelos Moleculares , Dados de Sequência Molecular , Pirimidinas/isolamento & purificação , Pirimidinas/uso terapêutico , RNA Bacteriano/genética , Reprodutibilidade dos Testes , Riboflavina/biossíntese , Riboswitch/genética , Especificidade por Substrato
10.
Mol Cell ; 49(5): 959-71, 2013 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-23375500

RESUMO

The proapoptotic Bcl-2 protein Bax is predominantly found in the cytosol of nonapoptotic cells and is commonly thought to translocate to mitochondria following an apoptotic stimulus. The current model for Bax activation is that BH3 proteins bind to cytosolic Bax, initiating mitochondrial targeting and outer-membrane permeabilization. Here, we challenge this and show that Bax is constitutively targeted to mitochondria but in nonapoptotic cells is constantly translocated back to the cytosol. Using live-cell spinning-disk confocal imaging with a combination of FLIP, FRAP, and photoactivatable GFP-Bax, we demonstrate that disrupting adhesion-dependent survival signals slows the rate of Bax's dissociation from mitochondria, leading to its accumulation on the outer mitochondrial membrane. The overall accumulation of mitochondrial Bax following loss of survival signaling sensitizes cells to proapoptotic BH3 proteins. Our findings show that Bax is normally in a dynamic equilibrium between cytosol and mitochondria, enabling fluctuations in survival signals to finely adjust apoptotic sensitivity.


Assuntos
Apoptose , Citosol/metabolismo , Mitocôndrias/metabolismo , Proteína X Associada a bcl-2/genética , Animais , Células Cultivadas , Células HEK293 , Humanos , Camundongos , Membranas Mitocondriais/metabolismo , Transfecção , Proteína X Associada a bcl-2/metabolismo
11.
J Oncol Pharm Pract ; 27(1): 78-87, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32228132

RESUMO

BACKGROUND: Temozolomide oral suspension is not commercially available. OBJECTIVE: To evaluate the stability of three temozolomide 10 mg/mL suspensions prepared in Oral Mix SF® in three container types stored at 4°C and 23°C. METHODS: Using commercial capsules, three separate batches of three different temozolomide 10 mg/mL formulations (Oral Mix SF® with PK-30; PK-30 and citric acid; and neither PK-30 nor citric acid) were made and stored in three container types (amber glass bottles, amber polyethylene terephthalate bottles, and polypropylene oral syringes). The aliquots in each container type were stored protected from light, half at 25°C and half at 4°C. On study days 0, 5, 8, 14, 21, 28, 35, 42, and 56, physical properties of samples from each container type at each temperature were assessed, and the temozolomide concentration was determined using a stability-indicating method. The beyond-use-date (time to achieve 90% of initial concentration calculated using the lower limit of the 95% confidence interval of the observed degradation rate) was calculated. RESULTS: Samples stored at 25°C turned from white to orange within seven days. Temozolomide crystals were observed in all samples. Concentration changes due to study day and temperature (p < 0.001) were observed but not due to container (p = 0.991) or formulation (p = 0.987). The beyond-use-date of all formulations in all container types was 56 days at 4°C and 6 days at 23°C. CONCLUSIONS: We recommend that these temozolomide 10 mg/mL formulations be stored at 4°C and be assigned a beyond-use-date of 30 days.


Assuntos
Antineoplásicos Alquilantes/química , Temozolomida/química , Cristalização , Composição de Medicamentos , Embalagem de Medicamentos , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Vidro , Plásticos , Seringas , Temperatura
12.
Proc Natl Acad Sci U S A ; 115(28): E6614-E6621, 2018 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-29941590

RESUMO

The outer membrane (OM) of Gram-negative bacteria forms a robust permeability barrier that blocks entry of toxins and antibiotics. Most OM proteins (OMPs) assume a ß-barrel fold, and some form aqueous channels for nutrient uptake and efflux of intracellular toxins. The Bam machine catalyzes rapid folding and assembly of OMPs. Fidelity of OMP biogenesis is monitored by the σE stress response. When OMP folding defects arise, the proteases DegS and RseP act sequentially to liberate σE into the cytosol, enabling it to activate transcription of the stress regulon. Here, we identify batimastat as a selective inhibitor of RseP that causes a lethal decrease in σE activity in Escherichia coli, and we further identify RseP mutants that are insensitive to inhibition and confer resistance. Remarkably, batimastat treatment allows the capture of elusive intermediates in the OMP biogenesis pathway and offers opportunities to better understand the underlying basis for σE essentiality.


Assuntos
Proteínas da Membrana Bacteriana Externa , Endopeptidases , Proteínas de Escherichia coli , Escherichia coli , Proteínas de Membrana , Desdobramento de Proteína , Fatores de Transcrição , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Endopeptidases/genética , Endopeptidases/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Fatores de Transcrição/metabolismo
13.
Clin Infect Dis ; 71(11): 2897-2904, 2020 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-31813967

RESUMO

BACKGROUND: Antimicrobial resistance (AMR) constitutes an international public health threat widely believed to result from excessive antimicrobial use (AMU). Numerous authorities have recommended antimicrobial stewardship programs (ASPs) to curb the selection of AMR, but there is a lack of data confirming this benefit. METHODS: A controlled interrupted time-series study spanning 14 years was performed to assess impact of a comprehensive hospital-based ASP that included pharmacist-led audit and feedback on institutional AMR. Patient-level microbiologic and AMU data were obtained from October 2002 to September 2016. Poisson regression models were used to identify changes in the incidence and trend of hospital-acquired (HA) antibiotic-resistant organisms (AROs) and multidrug-resistant organisms (MDROs). Changes in community-acquired (CA)-ARO, CA-MDRO, and inpatient AMU were assessed as controls and process outcomes. RESULTS: Statistically significant shifts in AMU, HA-ARO, and HA-MDRO trends coinciding with ASP implementation were observed, corresponding with a 9% reduction in HA-ARO burden (incidence rate ratio [IRR], 0.91 [95% confidence interval {CI}, .83-.99]; P = .03) and a 13% reduction in HA-MDRO burden (IRR, 0.87 [95% CI, .73-1.04]; P = .13) in the intervention period. In contrast, CA-ARO and CA-MDRO incidence continued to rise, with 40% (IRR, 1.40 [95% CI, 1.28-1.54]; P < .0001) and 68% (IRR, 1.68 [95% CI, 1.57-1.82]; P < .0001) increases in burden found, respectively. CONCLUSIONS: Implementation of a comprehensive ASP resulting in reduced AMU was associated with a significant reduction in institutional AMR, even though community AMR increased during the same period. These results confirm that ASPs play an important role in the fight against AMR.


Assuntos
Anti-Infecciosos , Gestão de Antimicrobianos , Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana , Humanos , Análise de Séries Temporais Interrompida
14.
J Contemp Dent Pract ; 21(3): 249-252, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32434969

RESUMO

AIM: The purpose of this study was to survey all United States Air Force (USAF) general dentists regarding their experience with computer-aided design/computer-aided manufacturing (CAD/CAM) while in a dental school. Dental school graduation year and location was compared to the type and amount of CAD/CAM training and clinical experience during dental school to better understand the differences and influence of this technology. MATERIALS AND METHODS: A survey consisting of six questions was sent through e-mail to 546 general dentists in the AF Dental Corps in 2018 of which 306 replied (56% response rate). RESULTS: Dentists who graduated in 2005 or earlier and between 2006 and 2009 stated they did not receive CAD/CAM training in dental school, while more respondents in the group of graduation years 2014-2017 stated that they did receive training. About 11% of the respondents who graduated in 2014-2017 completed 6-10 restorations and 9% completed 11 or more restorations compared to the other year groups. More respondents who graduated from a dental school in the southwest and southeast regions of the United States reported completing more restorations compared to other school regions. CONCLUSION: Computer-aided design/computer-aided manufacturing is now becoming a prevalent curriculum in US dental schools, both as a core requirement and an elective. Its training platforms varied from lectures and literature reviews to preclinical laboratory. CLINICAL SIGNIFICANCE: More respondents in the groups of graduation years 2014-2017 had completed more CAD/CAM restorations compared to other year groups; however, most of the respondents did not feel their training was sufficient enough to use CAD/CAM technology independently.


Assuntos
Desenho Assistido por Computador , Planejamento de Prótese Dentária , Odontologia Militar , Odontólogos , Humanos , Faculdades de Odontologia , Inquéritos e Questionários , Estados Unidos
15.
Ann Pharmacother ; 53(4): 348-356, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30345801

RESUMO

BACKGROUND: A number of centers across the world offer short daily hemodialysis (SDHD) treatments. To date, cefazolin pharmacokinetics have not been described in patients undergoing SDHD. OBJECTIVE: The purpose of this study was to investigate the effect of SDHD on the pharmacokinetics of cefazolin. METHODS: This was a prospective, open-label, pharmacokinetic study of cefazolin during SDHD in 10 noninfected patients. Participants received a 1-g intravenous (IV) infusion of cefazolin after SDHD on study day 1 and a second dose after SDHD on study day 2. To determine the concentration of cefazolin, 6 blood samples were drawn at 0, 1, 2, 2.3, 4, and 24 hours after initiation of dialysis on day 2, and 2 dialysate samples were drawn at 1 and 2 hours after initiation of dialysis on day 2. Samples were analyzed using high-performance liquid chromatography, and pharmacokinetic parameters were determined. RESULTS: Median interdialysis clearance was 0.16 L/h (interquartile range [IQR]: 0.11-0.21 L/h), and median intradialysis clearance was 1.95 L/h (IQR: 1.66-2.45 L/h). Median interdialysis half-life was 28.2 hours (IQR: 23.5-59.3 hours) as compared with a median intradialysis half-life of 2.3 hours (IQR: 1.7-2.7 hours). The median percentage removal of cefazolin during dialysis was 41% (IQR: 35%-53%). Conclusion and Relevance: Estimated cefazolin dialysis clearance is similar to previous estimates with conventional thrice-weekly regimens. Current dosing recommendations of 1 g IV post-SDHD achieve total serum drug concentrations greater than 40 mg/L in all patients, which is the total drug concentration required for bactericidal activity against Staphylococcus species.


Assuntos
Antibacterianos/sangue , Cefazolina/sangue , Diálise Renal/métodos , Adulto , Antibacterianos/administração & dosagem , Cefazolina/administração & dosagem , Creatinina/sangue , Feminino , Meia-Vida , Humanos , Infusões Intravenosas , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Tempo
16.
J Oncol Pharm Pract ; 25(8): 1907-1915, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31694495

RESUMO

PURPOSE: Use of aprepitant for chemotherapy-induced nausea and vomiting prophylaxis in patients unable to swallow capsules is hindered by the lack of a commercially available oral liquid formulation in many jurisdictions. A stable oral suspension can be extemporaneously prepared using commercially available capsules. We aimed to determine the bioavailability of this aprepitant suspension relative to the capsule. METHODS: This two-period crossover study enrolled 17 healthy adult volunteers. Volunteers received a single 125 mg aprepitant dose during each study period. Order of formulation presentation (capsule vs suspension first) was randomized. Thirteen blood samples were collected over a 48-h period. Aprepitant plasma concentrations were determined using liquid chromatography-mass spectroscopy. Relative bioavailability was defined as the geometric least squares mean ratio for area under the concentration versus time curve (AUC) from time zero to infinity of the aprepitant suspension versus the capsule. Bioequivalence, defined as per Health Canada guidelines, was assessed as a secondary aim. RESULTS: Relative bioavailability of the aprepitant suspension was 82.3% (90% CI: 69.09-98.00%). Bioequivalence was not established: geometric least squares mean ratios (suspension/capsule) for AUC time zero to 48 h and maximum concentration were 87.8% (90% CI: 75.48-102.16%) and 86.1% (90% CI: 75.59-98.16%), respectively. No serious adverse events were observed. CONCLUSIONS: With a relative bioavailability of 82.3%, the extemporaneous aprepitant oral suspension was well-absorbed relative to the capsule. Though not bioequivalent to the oral capsule, the clinical use of this aprepitant oral suspension in adult and pediatric patients unable to swallow capsules is likely to be effective and safe.


Assuntos
Aprepitanto/administração & dosagem , Administração Oral , Adulto , Aprepitanto/farmacocinética , Área Sob a Curva , Disponibilidade Biológica , Canadá , Cápsulas , Estudos Cross-Over , Feminino , Humanos , Masculino , Estudos Prospectivos , Suspensões , Equivalência Terapêutica , Adulto Jovem
19.
Nonlinear Dyn ; 90(4): 2959-2978, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-32009736

RESUMO

The cyclic nature of the stick-slip phenomenon may cause catastrophic failures in drill-strings or at the very least could lead to the wear of expensive equipment. Therefore, it is important to study the drilling parameters which can lead to stick-slip, in order to develop appropriate control methods for suppression. This paper studies the stick-slip oscillations encountered in drill-strings from both numerical and experimental points of view. The numerical part is carried out based on path-following methods for non-smooth dynamical systems, with a special focus on the multistability in drill-strings. Our analysis shows that, under a certain parameter window, the multistability can be used to steer the response of the drill-strings from a sticking equilibrium or stick-slip oscillation to an equilibrium with constant drill-bit rotation. In addition, a small-scale downhole drilling rig was implemented to conduct a parametric study of the stick-slip phenomenon. The parametric study involves the use of two flexible shafts with varying mechanical properties to observe the effects that would have on stick-slip during operation. Our experimental results demonstrate that varying some of the mechanical properties of the drill-string could in fact control the nature of stick-slip oscillations.

20.
Catheter Cardiovasc Interv ; 88(6): 912-922, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27801973

RESUMO

Current practice of sedation and anesthesia for patients undergoing pediatric congenital cardiac catheterization laboratory (PCCCL) procedures is known to vary among institutions, a multi-society expert panel with representatives from the Congenital Heart Disease Council of the Society for Cardiovascular Angiography and Interventions (SCAI), the Society for Pediatric Anesthesia (SPA) and the Congenital Cardiac Anesthesia Society (CCAS) was convened to evaluate the types of sedation and personnel necessary for procedures performed in the PCCCL. The goal of this panel was to provide practitioners and institutions performing these procedures with guidance consistent with national standards and to provide clinicians and institutions with consensus-based recommendations and the supporting references to encourage their application in quality improvement programs. Recommendations can neither encompass all clinical circumstances nor replace the judgment of individual clinicians in the management of each patient. The science of medicine is rooted in evidence, and the art of medicine is based on the application of this evidence to the individual patient. This expert consensus statement has adhered to these principles for optimal management of patients requiring sedation and anesthesia. What follows are recommendations for patient monitoring in the PCCCL regardless of whether minimal or no sedation is being used or general anesthesia is being provided by an anesthesiologist. © 2016 Wiley Periodicals Inc.


Assuntos
Anestesia Geral/normas , Cateterismo Cardíaco , Sedação Consciente/normas , Consenso , Cardiopatias Congênitas/cirurgia , Guias de Prática Clínica como Assunto , Angiografia , Criança , Cardiopatias Congênitas/diagnóstico , Humanos
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