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In Alzheimer's disease (AD) clinical trials, disease-modifying therapies are expected to slow the rate of disease progression. Treatment effects are evaluated using a validated clinical scale as the difference between treatment and placebo in mean change from baseline to endpoint. Understanding the clinical relevance of this metric is not necessarily intuitive. Expressing active treatment-placebo difference as a time metric (i.e., months saved with treatment) has potential to provide a metric that is more easily and consistently interpreted. Using data from the TRAILBLAZER-ALZ study, time component tests (TCTs) were employed to determine the time saved with donanemab (an amyloid lowering drug) treatment. At study endpoint (Week 76), disease progression was delayed by 5.3 months and 5.2 months as measured by the Integrated Alzheimer's Disease Rating Scale (iADRS) and the Clinical Dementia Rating Sum of Boxes (CDR-SB), respectively.
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Doença de Alzheimer , Humanos , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/tratamento farmacológico , Resultado do Tratamento , Anticorpos Monoclonais/uso terapêutico , Testes de Estado Mental e Demência , Progressão da DoençaRESUMO
Pressurized metered dose inhalers are recommended to be used in combination with spacers, yet inhaler technique and adherence are poor. A novel digital "smart" spacer can record spacer use and technique errors and could facilitate personalized education. In this proof-of-concept study, we assessed the usability of the digital spacer and explored its effects on inhaler technique, adherence, long-term systemic drug exposure and clinical outcomes in COPD. Usability was deemed high. One month after personalized digital spacer inhaler education, the mean number of errors per patient per day decreased with 36%, from 6.40 errors/day to 4.07 errors/day (p = 0.038). Drug exposure was confirmed by bioanalytical scalp hair analysis of formoterol. No significant change in clinical outcomes was observed. This study demonstrates the digital spacer's potential value in inhaler education, but larger, longer-term studies are required.
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Broncodilatadores , Doença Pulmonar Obstrutiva Crônica , Administração por Inalação , Broncodilatadores/uso terapêutico , Fumarato de Formoterol/uso terapêutico , Humanos , Inaladores Dosimetrados , Nebulizadores e Vaporizadores , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológicoRESUMO
Human Precision-cut intestinal slices (hPCIS) are used to study intestinal physiology, pathophysiology, drug efficacy, toxicology, kinetics, and metabolism. However, the use of this ex vivo model is restricted to approximately a 24 h timeframe because of declining viability of the hPCIS during traditional culture. We hypothesized that we could extend the hPCIS viability by using organoid medium. Therefore, we cultured hPCIS for up to 72 h in organoid media [expansion medium (Emed) and differentiation medium (Dmed)]. After incubation, we assessed culture-induced changes on viability markers, specific cell type markers and we assessed the metabolic activity of enterocytes by measuring midazolam metabolite formation. We show that the adenosine triphosphate (ATP)/protein ratio of Emed-cultured hPCIS and morphology of both Emed- and Dmed-cultured hPCIS was improved compared to WME-cultured hPCIS. Emed-cultured hPCIS showed an increased expression of proliferation and stem cell markers, whereas Dmed-cultured hPCIS showed an increased expression of proliferation and enterocyte markers, along with increased midazolam metabolism. Using the Emed, the viability of hPCIS could be extended for up to 72 h, and proliferating stem cells remained preserved. Using Dmed, hPCS also remained viable for up to 72 h, and specifically rescued the metabolizing enterocytes during culture. In conclusion, by using two different organoid culture media, we could extend the hPCIS viability for up to 72 h of incubation and specifically steer stem cells or enterocytes towards their original function, metabolism, and proliferation, potentially allowing pharmacokinetic and toxicology studies beyond the 24 h timeframe.
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Intestinos , Midazolam , Meios de Cultura , Humanos , Inativação Metabólica , Midazolam/farmacologia , OrganoidesRESUMO
Dietary fiber (DF) is receiving increasing attention, and its importance in pig nutrition is now acknowledged. Although DF for pigs was frowned upon for a long time because of reductions in energy intake and digestibility of other nutrients, it has become clear that feeding DF to pigs can affect their well-being and health. This review aims to summarize the state of knowledge of studies on DF in pigs, with an emphasis on the underlying mode of action, by considering research using DF in sows as well as suckling and weaned piglets, and fattening pigs. These studies indicate that DF can benefit the digestive tracts and the health of pigs, if certain conditions or restrictions are considered, such as concentration in the feed and fermentability. Besides the chemical composition and the impact on energy and nutrient digestibility, it is also necessary to evaluate the possible physical and physiologic effects on intestinal function and intestinal microbiota, to better understand the relation of DF to animal health and welfare. Future research should be designed to provide a better mechanistic understanding of the physiologic effects of DF in pigs.
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Fibras na Dieta , Microbioma Gastrointestinal , Suínos , Animais , Feminino , Fibras na Dieta/análise , Microbioma Gastrointestinal/fisiologia , Ração Animal/análise , Dieta/veterináriaRESUMO
For the quantification of the sedative and anesthetic drug midazolam and its main (active) metabolites 1-hydroxymidazolam, 4-hydroxymidazolam and 1-hydroxymidazolam glucuronide in human serum, human EDTA plasma, human heparin plasma and human urine a single accurate method by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) has been developed. Protein precipitation as sample preparation, without the need of a time-consuming deglucuronidation step for the quantification of 1-hydroxymidazolam glucuronide, resulted in a simple and rapid assay suitable for clinical practice with a total runtime of only 1.1 min. The four components and the isotope-labeled internal standards were separated on a C18 column and detection was performed with a triple-stage quadrupole mass spectrometer operating in positive ionization mode. The method was validated based on the "Guidance for Industry Bioanalytical Method Validation" (Food and Drug Administration, FDA) and the "Guideline on bioanalytical method validation" of the European Medicines Agency (EMA). Linearity was proven over the ranges of 5-1500 µg/L for midazolam, 1-hydroxymidazolam and 4-hydroxymidazolam and 25-5000 µg/L for 1-hydroxymidazolam glucuronide, using a sample volume of 100 µL. Matrix comparison indicated that the assay is also applicable to other human matrices like EDTA and heparin plasma and urine. Stability experiments showed good results for the stability of midazolam, 1-hydroxymidazolam and 1-hydroxymidazolam glucuronide in serum, EDTA and heparin plasma and urine stored for 7 days under different conditions. At room temperature, 4-hydroxymidazo-lam is stable for 7 days in EDTA plasma, but stable for only 3 days in serum and heparin plasma and less than 24 h in urine. All four compounds were found to be stable in serum, EDTA plasma, heparin plasma and urine for 7 days after sample preparation and for 3 freeze-thaw cycles. The assay has been applied in therapeutic drug monitoring of midazolam for (pediatric) intensive care patients.
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Cromatografia Líquida de Alta Pressão/métodos , Midazolam , Espectrometria de Massas em Tandem/métodos , Idoso , Estabilidade de Medicamentos , Feminino , Humanos , Recém-Nascido , Limite de Detecção , Modelos Lineares , Midazolam/análogos & derivados , Midazolam/sangue , Midazolam/farmacocinética , Midazolam/urina , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Computerized cognitive assessments may improve Alzheimer's disease (AD) secondary prevention trial efficiency and accuracy. However, they require validation against standard outcomes and relevant biomarkers. OBJECTIVE: To assess the feasibility and validity of the tablet-based Computerized Cognitive Composite (C3). DESIGN: Cross-sectional analysis of cognitive screening data from the A4 study (Anti-Amyloid in Asymptomatic AD). SETTING: Multi-center international study. PARTICIPANTS: Clinically normal (CN) older adults (65-85; n=4486). MEASUREMENTS: Participants underwent florbetapir-Positron Emission Tomography for Aß+/- classification. They completed the C3 and standard paper and pencil measures included in the Preclinical Alzheimer's Cognitive Composite (PACC). The C3 combines memory measures sensitive to change over time (Cogstate Brief Battery-One Card Learning) and measures shown to be declining early in AD including pattern separation (Behavioral Pattern Separation Test- Object- Lure Discrimination Index) and associative memory (Face Name Associative Memory Exam- Face-Name Matching). C3 acceptability and completion rates were assessed using qualitative and quantitative methods. C3 performance was explored in relation to Aß+/- groups (n=1323/3163) and PACC. RESULTS: C3 was feasible for CN older adults to complete. Rates of incomplete or invalid administrations were extremely low, even in the bottom quartile of cognitive performers (PACC). C3 was moderately correlated with PACC (r=0.39). Aß+ performed worse on C3 compared with Aß- [unadjusted Cohen's d=-0.22 (95%CI: -0.31,-0.13) p<0.001] and at a magnitude comparable to the PACC [d=-0.32 (95%CI: -0.41,-0.23) p<0.001]. Better C3 performance was observed in younger, more educated, and female participants. CONCLUSIONS: These findings provide support for both the feasibility and validity of C3 and computerized cognitive outcomes more generally in AD secondary prevention trials.
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Doença de Alzheimer/diagnóstico , Ensaios Clínicos como Assunto , Testes de Estado Mental e Demência , Idoso , Peptídeos beta-Amiloides/metabolismo , Biomarcadores/metabolismo , Computadores , Estudos Transversais , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pesquisa Qualitativa , Prevenção SecundáriaRESUMO
INTRODUCTION: Metformin can accumulate and cause lactic acidosis in patients with renal insufficiency. Metformin is known to inhibit mitochondria, while renal secretion of the drug by proximal tubules indirectly requires energy. We investigated whether addition of metformin before or during ex vivo isolated normothermic machine perfusion (NMP) of porcine and rat kidneys affects its elimination. RESEARCH DESIGN AND METHODS: First, Lewis rats were pretreated with metformin or saline the day before nephrectomy. Subsequently, NMP of the kidney was performed for 90 min. Metformin was added to the perfusion fluid in one of three different concentrations (none, 30 mg/L or 300 mg/L). Second, metformin was added in increasing doses to the perfusion fluid during 4 hours of NMP of porcine kidneys. Metformin concentration was determined in the perfusion fluid and urine by liquid chromatography-tandem mass spectrometry. RESULTS: Metformin clearance was approximately 4-5 times higher than creatinine clearance in both models, underscoring secretion of the drug. Metformin clearance at the end of NMP in rat kidneys perfused with 30 mg/L was lower than in metformin pretreated rats without the addition of metformin during perfusion (both p≤0.05), but kidneys perfused with 300 mg/L trended toward lower metformin clearance (p=0.06). Creatinine clearance was not different between treatment groups. During NMP of porcine kidneys, metformin clearance peaked at 90 min of NMP (18.2±13.7 mL/min/100 g). Thereafter, metformin clearance declined, while creatinine clearance remained stable. This observation can be explained by saturation of metformin transporters with a Michaelis-Menten constant (95% CI) of 23.0 (10.0 to 52.3) mg/L. CONCLUSIONS: Metformin was secreted during NMP of both rat and porcine kidneys. Excretion of metformin decreased under increasing concentrations of metformin, which might be explained by saturation of metformin transporters rather than a self-inhibitory effect. It remains unknown whether a self-inhibitory effect contributes to metformin accumulation in humans with longer exposure times.
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Metformina , Preservação de Órgãos , Animais , Humanos , Rim , Perfusão , Ratos , Ratos Endogâmicos Lew , SuínosRESUMO
Sodium-glucose cotransporter 2 -inhibitors (SGLT2i) are oral glucose-lowering drugs that have also demonstrated cardioprotective and renoprotective effects. SGLT2i play an increasingly important role in the treatment of type 2 diabetes. Here we report a simple and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of three SGLT2i (canagliflozin, dapagliflozin and empagliflozin) in human plasma, serum and urine with a runtime of 1 min. Methanol was used as protein precipitating agent. Chromatographic separation was accomplished using a Waters ACQUITY UPLC HSS T3 1.8 µm; 2.1 × 50 mm column with a Waters ACQUITY UPLC HSS T3 1.8 µm VanGuard Pre-column; 2.1 × 5 mm, using gradient elution with ammonium acetate 20 mM (pH 5) and acetonitrile as mobile phase at a flow rate of 0.8 ml/min. Mass spectrometric analysis of the acetate adduct ions was carried out using electrospray with negative ionization and SRM mode. The assay was validated according to FDA and EMA guidelines, including selectivity, linearity, accuracy and precision, dilution integrity, stability and recovery. With a sample volume of 200 µl, linear ranges of 10-5000 µg/L, 1-500 µg/L and 2-1000 µg/L for canagliflozin, dapagliflozin and empagliflozin respectively, were achieved. The assay was successfully applied in two pharmacokinetic studies with dapagliflozin and empagliflozin. In conclusion, we developed and validated a simple, fast and robust LC-MS/MS method for the simultaneous quantification of canagliflozin, dapagliflozin and empagliflozin, that allows rapid analysis of large numbers of samples and can be used for both pharmacokinetic studies and biomedical analysis of canagliflozin, dapagliflozin and empagliflozin.
Assuntos
Cromatografia Líquida/métodos , Glucosídeos , Inibidores do Transportador 2 de Sódio-Glicose , Espectrometria de Massas em Tandem/métodos , Estabilidade de Medicamentos , Glucosídeos/sangue , Glucosídeos/química , Glucosídeos/farmacocinética , Glucosídeos/urina , Humanos , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Inibidores do Transportador 2 de Sódio-Glicose/sangue , Inibidores do Transportador 2 de Sódio-Glicose/química , Inibidores do Transportador 2 de Sódio-Glicose/farmacocinética , Inibidores do Transportador 2 de Sódio-Glicose/urinaRESUMO
Research has found that 24% of foreign domestic workers (FDWs) in Singapore have poor mental health (24%), with depressive symptoms being identified as the second most severe psychological symptoms [1]. The study assessed the acceptability and effectiveness of a 4-week cognitive behavioral therapy (CBT)-based paraprofessional training program for FDWs in Singapore on depression literacy and CBT knowledge (primary outcomes), depression-related stigma, as well as attitudes towards seeking professional help (secondary outcomes) immediately and 2 months following the training. Forty female Filipino FDWs were recruited and randomized into either a CBT-based paraprofessional training program or wait-list (WL) group. Participants completed outcome measures before, after, and 2 months following their training. No significant difference was found on changes on any of the outcome variables in the intervention group as compared to the WL group. Following training, both groups showed significantly improved depression literacy, CBT knowledge, and attitudes towards seeking professional help. These changes were sustained at 2-month follow-up. All participants indicated a high level of satisfaction with the training program. While findings from between-group analyses do not support the efficacy of the CBT-based paraprofessional training program in improving depression literacy and related outcomes, participation in the program was associated with improvements in several outcomes within the training group. Future research should explore adaptations to the program (e.g., in terms of training duration and modes of delivery) that would increase its efficacy in improving depression literacy and CBT knowledge among FDWs.
Assuntos
Terapia Cognitivo-Comportamental/educação , Zeladoria , Saúde Mental/etnologia , Grupo Associado , Adulto , Depressão/terapia , Emigrantes e Imigrantes , Feminino , Humanos , Pessoa de Meia-Idade , Filipinas/etnologia , Avaliação de Programas e Projetos de Saúde , SingapuraRESUMO
Microwave SQUID multiplexing has become a key technology for reading out large arrays of X-ray and gamma-ray microcalorimeters with mux factors of 100 or more. The desire for fast X-ray pulses that accommodate photon counting rates of hundreds or thousands of counts per second per sensor drives system design toward high sensor current slew rate. Typically, readout of high current slew rate events is accomplished by increasing the sampling rate, such that rates of order 1MHz may be necessary for some experiments. In our microwave multiplexed readout scheme, the effective sampling rate is set by the frequency of the flux-ramp modulation (f r) used to linearize the SQUID response. The maximum current slew rate between samples is then nominally Φ 0 f r/2M in (where M in is the input coupling) because it is generally not possible to distinguish phase shifts of > π from negative phase shifts of < -π. However, during a pulse, we know which direction the current ought to be slewing, and this makes it possible to reconstruct a pulse where the magnitude of the phase shift between samples is > π. We describe a practical algorithm to identify and reconstruct pulses that exceed this nominal slew rate limit on the rising edge. Using pulses produced by X-ray transition-edge sensors, we find that the pulse reconstruction has a negligible impact on energy resolution compared to arrival time effects induced by under-sampling the rising edge. This technique can increase the effective slew rate limit by more than a factor of two, thereby either reducing the resonator bandwidth required or extending the energy range of measurable photons. The extra margin could also be used to improve crosstalk or to decrease readout noise.
RESUMO
The Integrated Alzheimer's Disease (AD) Rating Scale (iADRS) is a composite tool that combines scores from the AD Assessment Scale-Cognitive subscale (ADAS-Cog) and the AD Cooperative Study - instrumental Activities of Daily Living (ADCS-iADL). It demonstrates acceptable psychometric properties, and is effective in capturing both disease progression and separation of placebo and active drug effect. We assessed the performance of iADRS in the solanezumab EXPEDITION3 study, an 80-week, placebo-controlled study of individuals with mild AD dementia. A statistically significant difference between placebo and active drug was observed for iADRS score change from baseline at Week 28 (p=0.028) through Week 80 (p=0.015). Across the Phase 3 solanezumab trials, iADRS was the only tool that consistently differentiated between solanezumab and placebo groups. These findings suggest that the iADRS is a useful integrated measurement tool for treatment trials of individuals with mild AD dementia.
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Doença de Alzheimer/diagnóstico , Doença de Alzheimer/tratamento farmacológico , Anticorpos Monoclonais Humanizados/uso terapêutico , Índice de Gravidade de Doença , Progressão da Doença , Feminino , Humanos , Masculino , PsicometriaRESUMO
The Alzheimer's Disease Assessment Scale's cognitive subscale (ADAS-Cog) has been widely used as an outcome measure in Alzheimer's Disease (AD) clinical trials. In its original form (ADAS-Cog11), the scale has been used successfully in mild-to-moderate AD dementia populations, but its use is more limited in the study of earlier disease (mild cognitive impairment [MCI] or mild dementia due to AD) owing to lack of appropriate sensitivity of some items. With recent focus on earlier treatment, efforts have focused on the development of more sensitive tools, including the Clinical Dementia Rating-Sum of Boxes (CDR-SB), a global assessment tool to evaluate both cognition and function. The ability of the ADAS-Cog and CDR-SB to detect treatment group differences in the clinical trial environment has not been systematically studied. The aim of this analysis was to compare the utility of these tools in detecting treatment group differences, by reviewing study findings identified through advanced searches of clinicaltrials.gov and Ovid, and press releases and scientific presentations. Findings from placebo-controlled studies of ≥ 6m duration and enrolling >100 participants were included; reporting of both the ADAS-Cog and CDR-SB at endpoint was also a requirement. Of the >300 records identified, 34 studies fulfilled the criteria. There were significant placebo versus active drug group differences based on findings from at least one measure for 14 studies. The ADAS-Cog detected treatment differences more frequently than the CDR-SB. Based on these and previously published findings, the ADAS-Cog appears more useful than the CDR-SB in detecting treatment group differences.
Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/terapia , Testes de Estado Mental e Demência/normas , Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Disfunção Cognitiva/diagnóstico , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do TratamentoRESUMO
Ertapenem is a carbapenem antibiotic with activity against Mycobacterium tuberculosis Dose simulations in a hollow-fiber infection model showed that 2,000 mg once daily is an appropriate dose to be tested in clinical studies. Before using this dose in a phase II study, the aim of this prospective pharmacokinetic study was to confirm the pharmacokinetics of 2,000 mg once daily in tuberculosis (TB) patients. Twelve TB patients received a single intravenous dose of 2,000 mg ertapenem as a 30-min infusion. Blood samples were collected at 0, 0.5, 1, 2, 3, 4, 8, 12, and 24 h postadministration. Drug concentrations were measured using a validated liquid chromatography-tandem mass spectrometry assay. A large interindividual variation in the pharmacokinetics of ertapenem was observed. The median (interquartile range) area under the plasma concentration-time curve to infinity (AUC0-∞) was 2,032 (1,751 to 2,346) mg · h/liter, the intercompartmental clearance (CL12) was 1.941 (0.979 to 2.817) liters/h, and the volume of distribution in the central compartment (V1) was 1.514 (1.064 to 2.210) liters. A more than dose-proportional increase in AUC was observed compared to results reported for 1,000 mg ertapenem in multidrug-resistant TB patients. Based on a MIC of 1.0 mg/liter, 11 out of 12 patients would have reached the target value of unbound drug exceeding the MIC over 40% of the time (f40% T>MIC). In conclusion, this study shows that 2,000 mg ertapenem once daily in TB patients reached the expected f40% T>MIC for most of the patients, and exploration in a phase 2 study can be advocated.
Assuntos
Antituberculosos/farmacocinética , Antituberculosos/uso terapêutico , Ertapenem/farmacocinética , Tuberculose/tratamento farmacológico , Adulto , Antituberculosos/administração & dosagem , Ertapenem/administração & dosagem , Ertapenem/uso terapêutico , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Estudos ProspectivosRESUMO
Microwave SQUID multiplexing is a promising technique for multiplexing large arrays of transition edge sensors. A major bottleneck in the development and distribution of microwave SQUID multiplexer chips occurs in the time-intensive design testing and quality assurance stages. To obtain useful RF measurements, these devices must be cooled to temperatures below 500 mK. The need for a more efficient system to screen microwave multiplexer chips has grown as the number of chips requested by collaborators per year reaches into the hundreds. We have therefore assembled a test bed for microwave SQUID circuits, which decreases screening time for four 32-channel chips from 24 h in an adiabatic demagnetization refrigerator to approximately 5 h in a helium dip probe containing a closed cycle 3He sorption refrigerator. We discuss defining characteristics of these microwave circuits and the challenges of establishing an efficient testing setup for them.
RESUMO
Several ongoing clinical development programs are investigating potential disease-modifying treatments for Alzheimer's disease (AD), including lanabecestat (AZD3293/LY3314814). Lanabecestat is a brain-permeable oral inhibitor of human beta-site amyloid (Aß) precursor protein-cleaving enzyme 1 (BACE1) that reduces Aß production. As a potent BACE1 inhibitor, lanabecestat significantly reduced soluble Aß species and soluble amyloid precursor proteins (sAPPß) in mouse, guinea pig, and dog in a time- and dose-dependent manner. Significant reductions in plasma and cerebrospinal fluid (CSF) Aß1-40 and Aß1-42 were observed in Phase 1 studies of healthy subjects and AD patients treated with lanabecestat. Three lanabecestat trials are ongoing and intended to support registration in Early AD: (1) Phase 2/3 study in patients with mild cognitive impairment (MCI) due to AD and mild AD dementia (AMARANTH, NCT02245737); (2) Delayed-start extension study (AMARANTH-EXTENSION, NCT02972658) for patients who have completed treatment in the AMARANTH Study; and (3) Phase 3 study in mild AD dementia (DAYBREAK-ALZ, NCT02783573). This review will discuss the development of lanabecestat, results from the completed nonclinical and clinical studies, as well as describe the ongoing Phase 3 clinical trials.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Imidazóis/farmacologia , Compostos de Espiro/farmacologia , Doença de Alzheimer/sangue , Doença de Alzheimer/líquido cefalorraquidiano , Doença de Alzheimer/tratamento farmacológico , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Ensaios Clínicos como Assunto , Disfunção Cognitiva/sangue , Disfunção Cognitiva/líquido cefalorraquidiano , Disfunção Cognitiva/tratamento farmacológico , Inibidores Enzimáticos/farmacocinética , Inibidores Enzimáticos/uso terapêutico , Humanos , Imidazóis/farmacocinética , Imidazóis/uso terapêutico , Compostos de Espiro/farmacocinética , Compostos de Espiro/uso terapêuticoRESUMO
Reduction of the CP content in the diets of piglets requires supplementation with crystalline essential amino acids (AA). Data on the leucine (Leu) and histidine (His) requirements of young pigs fed low-CP diets are limited and have primarily been obtained from nonlinear models. However, these models do not consider the possible decline in appetite and growth that can occur when pigs are fed excessive amounts of AA such as Leu. Therefore, two dose-response studies were conducted to estimate the standardised ileal digestible (SID) Leu : lysine (Lys) and His : Lys required to optimise the growth performance of young pigs. In both studies, the average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratio (G : F) were determined during a 6-week period. To ensure that the diets had sub-limiting Lys levels, a preliminary Lys dose-response study was conducted. In the Leu study, 60 35-day-old piglets of both sexes were randomly assigned to one of five treatments and fed a low-CP diet (15%) with SID Leu : Lys levels of 83%, 94%, 104%, 115% or 125%. The His study used 120 31-day-old piglets of both sexes, which were allotted to one of five treatments and fed a low-CP diet (14%) with SID His : Lys levels of 22%, 26%, 30%, 34% or 38%. Linear broken-line, curvilinear-plateau and quadratic-function models were used for estimations of SID Leu : Lys and SID His : Lys. The minimum SID Leu : Lys level needed to maximise ADG, ADFI and G : F was, on average, 101% based on the linear broken-line and curvilinear-plateau models. Using the quadratic-function model, the minimum SID Leu : Lys level needed to maximise ADG, ADFI and G : F was 108%. Data obtained from the quadratic-function analysis further showed that a ±10% deviation from the identified Leu requirement was accompanied by a small decline in the ADG (-3%). The minimum SID His : Lys level needed to maximise ADG, ADFI and G : F was 27% and 28% using the linear broken-line and curvilinear-plateau models, respectively, and 33% using the quadratic-function model. The preferred model to estimate the His requirement was the curvilinear-plateau model. However, a 10% reduction in the SID His : Lys level was associated with an 11% reduction in the ADG. In conclusion, the SID Leu : Lys level needed to maximise growth was 108% when using the quadratic-function model as the best-fitting model. The minimum SID His : Lys level required to optimise growth was 28% when using the curvilinear-plateau model as the best-fitting model.
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Ração Animal/análise , Dieta com Restrição de Proteínas/veterinária , Histidina/administração & dosagem , Histidina/farmacologia , Leucina/administração & dosagem , Leucina/farmacologia , Suínos/crescimento & desenvolvimento , Suínos/metabolismo , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Suplementos Nutricionais , Feminino , Histidina/metabolismo , Íleo/metabolismo , Leucina/metabolismo , Lisina/administração & dosagem , Lisina/metabolismo , Lisina/farmacologia , MasculinoRESUMO
Drug susceptibility tests (DSTs) for Mycobacterium tuberculosis require at least 7 days of incubation. Drugs that are unstable at 37°C, such as ertapenem, are likely to be degraded before killing or inhibiting slow-growing bacteria. This would alter the MICs of these drugs, including ertapenem, leading to falsely high MICs. Here, we describe a new strategy we developed to perform DSTs and measure MICs for such unstable compounds.
Assuntos
Antibacterianos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , beta-Lactamas/farmacologia , Ertapenem , Testes de Sensibilidade Microbiana , Mycobacterium/efeitos dos fármacosRESUMO
For Alzheimer's disease treatment trials that focus on the pre-dementia stage of disease, outcome measures are needed that will enable assessment of disease progression in patients who are clinically normal. The EU/US CTAD Task Force, an international collaboration of investigators from industry, academia, non-profit foundations, and regulatory agencies, met in Philadelphia, Pennsylvania, USA, on November 19, 2014 to discuss existing and novel outcome assessments that may be useful in pre-dementia trials. Composite measures that assess changes in episodic memory, executive function, global cognition, and global function have recently been developed by a number of groups and appear to be sensitive at this stage. Functional measures that involve real-life complex tasks also appear to capture early subtle changes in pre-dementia subjects and have the advantage of representing clinically meaningful change. Patient reported outcomes and novel CSF and imaging biomarkers have also shown promise. More studies are needed to validate all of these tests in the pre-dementia population. Many of them have been incorporated as exploratory measures in ongoing or planned trials.