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1.
PRiMER ; 7: 25, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37791055

RESUMO

Background and Objectives: Future Doctors (FD), a high school pathway program, was developed to address the lack of compositional diversity in the health professions at our health sciences campus. Methods: We obtained, analyzed, and compared data on FD student demographic and educational achievement at undergraduate and graduate programs at the University of Utah and graduate programs at other institutions to non-FD students. We followed students from high school to graduate school. Results: We analyzed data from 1,897 FD participants (2014-2019). FD participants were 71% women, with 50.3% identifying as students of color. Ninety-eight students matriculated in graduate school, with 75 (76%) remaining at University of Utah and 45 (46%) attending health sciences graduate programs. Conclusions: FD student cohorts are more diverse than those in the University of Utah undergraduate and graduate programs, contributing to the diversity of those programs. More research is needed to ensure that graduate school gains are evidenced in all underrepresented groups.

2.
R Soc Open Sci ; 10(10): 221108, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37800157

RESUMO

Several predator-prey systems are in flux as an indirect result of climate change. In the Arctic, earlier sea-ice loss is driving polar bears (Ursus maritimus) onto land when many colonial nesting seabirds are breeding. The result is a higher threat of nest predation for birds with potential limited ability to respond. We quantified heart rate change in a large common eider (Somateria mollissima) breeding colony in the Canadian Arctic to explore their adaptive capacity to keep pace with the increasing risk of egg predation by polar bears. Eiders displayed on average higher heart rates from baseline when polar bears were within their field of view. Moreover, eiders were insensitive to variation in the distance bears were to their nests, but exhibited mild bradycardia (lowered heart rate) the longer the eider was exposed to the bear given the hen's visibility. Results indicate that a limited ability to assess the risks posed by polar bears may result in long-term fitness consequences for eiders from the increasing frequency in interactions with this predator.

3.
Harm Reduct J ; 20(1): 65, 2023 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-37161460

RESUMO

BACKGROUND: Electronic nicotine delivery systems (ENDS), such as the JUUL system, are nicotine products for adults who currently smoke cigarettes but are looking for an alternative to combustible cigarettes. Sales of ENDS products were legislatively acknowledged and authorized federally in Canada with the Royal Assent of the Tobacco and Vaping Products Act in 2018. METHODS: With the unique dataset from a major chain retailer in Canada, we evaluated the impacts of JUUL market entry on cigarette sales across Canada from January 2017 to August 2019 using two-way fixed effects panel regression models by leveraging on the entry time variation at the city level. We conducted various robustness checks and a permutation test to validate our results. RESULTS: Our estimates suggested that JUUL market entry was, on average, significantly correlated with a 1.65% per-month decrease in cigarette sales during the initial months, and with a potentially larger impact on urban areas. Our results were robust across various specifications and tests. These findings implied that JUUL and combustible cigarettes act as economic substitutes during the study time period in Canada. CONCLUSIONS: These results suggested that local availability of ENDS products, such as JUUL, has the potential to reduce local cigarette consumption.


Assuntos
Produtos do Tabaco , Adulto , Humanos , Nicotina , Canadá , Comércio
4.
Eur J Hum Genet ; 31(3): 353-359, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36207621

RESUMO

Nystagmus (involuntary, rhythmical eye movements) can arise due to sensory eye defects, in association with neurological disorders or as an isolated condition. We identified a family with early onset nystagmus and additional neurological features carrying a partial duplication of FGF14, a gene associated with spinocerebellar ataxia type 27 (SCA27) and episodic ataxia. Detailed eye movement analysis revealed oculomotor anomalies strikingly similar to those reported in a previously described four-generation family with early onset nystagmus and linkage to a region on chromosome 13q31.3-q33.1 (NYS4). Since FGF14 lies within NYS4, we revisited the original pedigree using whole genome sequencing, identifying a 161 kb heterozygous deletion disrupting FGF14 and ITGBL1 in the affected individuals, suggesting an FGF14-related condition. Therefore, our study reveals the genetic variant underlying NYS4, expands the spectrum of pathogenic FGF14 variants, and highlights the importance of screening FGF14 in apparently isolated early onset nystagmus.


Assuntos
Nistagmo Patológico , Degenerações Espinocerebelares , Humanos , Ataxia/genética , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Integrina beta1/genética , Linhagem , Degenerações Espinocerebelares/genética
5.
Sci Rep ; 12(1): 18804, 2022 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-36335150

RESUMO

Aerial drones are increasingly being used as tools for ecological research and wildlife monitoring in hard-to-access study systems, such as in studies of colonial-nesting birds. Despite their many advantages over traditional survey methods, there remains concerns about possible disturbance effects that standard drone survey protocols may have on bird colonies. There is a particular gap in the study of their influence on physiological measures of stress. We measured heart rates of incubating female common eider ducks (Somateria mollissima) to determine whether our drone-based population survey affected them. To do so, we used heart-rate recorders placed in nests to quantify their heart rate in response to a quadcopter drone flying transects 30 m above the nesting colony. Eider heart rate did not change from baseline (measured in the absence of drone survey flights) by a drone flying at a fixed altitude and varying horizontal distances from the bird. Our findings suggest that carefully planned drone-based surveys of focal species have the potential to be carried out without causing physiological impacts among colonial-nesting eiders.


Assuntos
Patos , Dispositivos Aéreos não Tripulados , Animais , Feminino , Patos/fisiologia , Aves , Animais Selvagens , Organismos Aquáticos
6.
Oecologia ; 197(3): 661-674, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34657196

RESUMO

Droughts can affect invertebrate communities in wetlands, which can have bottom-up effects on the condition and survival of top predators. Shorebirds, key predators at coastal wetlands, have experienced widespread population declines and could be negatively affected by droughts. We explored, in detail, the effects of drought on multiple aspects of shorebird stopover and migration ecology by contrasting a year with average wet/dry conditions (2016) with a year with moderate drought (2017) at a major subarctic stopover site on southbound migration. We also examined the effects of drought on shorebird body mass during stopover across 14 years (historical: 1974-1982 and present-day: 2014-2018). For the detailed comparison of two years, in the year with moderate drought we documented lower invertebrate abundance at some sites, higher prey family richness in shorebird faecal samples, lower shorebird refuelling rates, shorter stopover durations for juveniles, and, for most species, a higher probability of making a subsequent stopover in North America after departing the subarctic, compared to the year with average wet/dry conditions. In the 14-year dataset, shorebird body mass tended to be lower in drier years. We show that even short-term, moderate drought conditions can negatively affect shorebird refuelling performance at coastal wetlands, which may carry-over to affect subsequent stopover decisions. Given shorebird population declines and predicted changes in the severity and duration of droughts with climate change, researchers should prioritize a better understanding of how droughts affect shorebird refuelling performance and survival.


Assuntos
Migração Animal , Áreas Alagadas , Animais , Secas , Ecologia , Invertebrados
7.
Toxicology ; 454: 152753, 2021 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-33741493

RESUMO

The phytochemical sulforaphane (SF) has gained interest for its apparent association with reduced cancer risk and other cytoprotective properties, at least some of which are attributed to activation of the transcription factor Nrf2. Repair of bulky DNA adducts is important for mitigating carcinogenesis from exogenous DNA damaging agents, but it is unknown whether in vivo treatment with SF affects adduct repair. At 12 h following a single oral dose of 100 mg/kg SF, an almost doubling in activity for repair of pyridyloxobutylated DNA was observed in CD-1 mouse liver nuclear extracts, but not in lung extracts. This change at 12 h in repair activity was preceded by the induction of Nrf2-regulated genes but not accompanied by changes in levels of the specific nucleotide excision repair (NER) proteins XPC, XPA, XPB and p53 or in binding of hepatic XPC, XPA and XPB to damaged DNA. SF also did not significantly alter histone deacetylase activity as measured by acetylated histone H3 levels, or stimulate formation of γ-H2A.X, a marker of DNA damage. A significant reduction in oxidative DNA damage, as measured by 8-OHdG (a biomarker of oxidative DNA damage), was observed only in DNA from the lungs of SF-treated mice 3 h post-dosing. These results suggest that the ability of SF to increase bulky adduct repair activity is organ-selective and is consistent with activation of the Nrf2 signaling pathway.


Assuntos
Anticarcinógenos/farmacologia , Dano ao DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Isotiocianatos/farmacologia , Sulfóxidos/farmacologia , Animais , Anticarcinógenos/administração & dosagem , Adutos de DNA/efeitos dos fármacos , Feminino , Isotiocianatos/administração & dosagem , Fígado/efeitos dos fármacos , Fígado/metabolismo , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sulfóxidos/administração & dosagem
8.
Handb Exp Pharmacol ; 257: 177-196, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31628600

RESUMO

Insufficient description of experimental practices can contribute to difficulties in reproducing research findings. In response to this, "minimum information" guidelines have been developed for different disciplines. These standards help ensure that the complete experiment is described, including both experimental protocols and data processing methods, allowing a critical evaluation of the whole process and the potential recreation of the work. Selected examples of minimum information checklists with relevance for in vitro research are presented here and are collected by and registered at the MIBBI/FAIRsharing Information Resource portal.In addition, to support integrative research and to allow for comparisons and data sharing across studies, ontologies and vocabularies need to be defined and integrated across areas of in vitro research. As examples, this chapter addresses ontologies for cells and bioassays and discusses their importance for in vitro studies.Finally, specific quality requirements for important in vitro research tools (like chemical probes, antibodies, and cell lines) are suggested, and remaining issues are discussed.


Assuntos
Pesquisa Biomédica , Técnicas In Vitro/normas , Projetos de Pesquisa
9.
Behav Res Methods ; 51(5): 2074-2084, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30875024

RESUMO

Infantile nystagmus (IN) describes a regular, repetitive movement of the eyes. A characteristic feature of each cycle of the IN eye movement waveform is a period in which the eyes are moving at minimal velocity. This so-called "foveation" period has long been considered the basis for the best vision in individuals with IN. In recent years, the technology for measuring eye movements has improved considerably, but there remains the challenge of calibrating the direction of gaze in tracking systems when the eyes are continuously moving. Identifying portions of the nystagmus waveform suitable for calibration typically involves time-consuming manual selection of the foveation periods from the eye trace. Without an accurate calibration, the exact parameters of the waveform cannot be determined. In this study, we present an automated method for segmenting IN waveforms with the purpose of determining the foveation positions to be used for calibration of an eye tracker. On average, the "point of regard" was found to be within 0.21° of that determined by hand-marking by an expert observer. This method enables rapid clinical quantification of waveforms and the possibility of gaze-contingent research paradigms being performed with this patient group.


Assuntos
Calibragem , Medições dos Movimentos Oculares , Automação , Movimentos Oculares , Humanos , Nistagmo Patológico , Acuidade Visual
10.
Mod Rheumatol ; 29(3): 510-522, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-29862859

RESUMO

OBJECTIVES: Bruton's tyrosine kinase (BTK) is a non-receptor tyrosine kinase required for intracellular signaling downstream of multiple immunoreceptors. We evaluated ABBV-105, a covalent BTK inhibitor, using in vitro and in vivo assays to determine potency, selectivity, and efficacy to validate the therapeutic potential of ABBV-105 in inflammatory disease. METHODS: ABBV-105 potency and selectivity were evaluated in enzymatic and cellular assays. The impact of ABBV-105 on B cell function in vivo was assessed using mechanistic models of antibody production. Efficacy of ABBV-105 in chronic inflammatory disease was evaluated in animal models of arthritis and lupus. Measurement of BTK occupancy was employed as a target engagement biomarker. RESULTS: ABBV-105 irreversibly inhibits BTK, demonstrating superior kinome selectivity and is potent in B cell receptor, Fc receptor, and TLR-9-dependent cellular assays. Oral administration resulted in rapid clearance in plasma, but maintenance of BTK splenic occupancy. ABBV-105 inhibited antibody responses to thymus-independent and thymus-dependent antigens, paw swelling and bone destruction in rat collagen induced arthritis, and reduced disease in an IFNα-accelerated lupus nephritis model. BTK occupancy in disease models correlated with in vivo efficacy. CONCLUSION: ABBV-105, a selective BTK inhibitor, demonstrates compelling efficacy in pre-clinical mechanistic models of antibody production and in models of rheumatoid arthritis and lupus.


Assuntos
Tirosina Quinase da Agamaglobulinemia/antagonistas & inibidores , Anti-Inflamatórios/uso terapêutico , Antirreumáticos/uso terapêutico , Artrite Experimental/tratamento farmacológico , Animais , Anti-Inflamatórios/farmacologia , Antirreumáticos/farmacologia , Linhagem Celular , Humanos , Ratos , Ratos Endogâmicos Lew , Spodoptera
11.
Br Ir Orthopt J ; 15(1): 82-88, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-32999978

RESUMO

Pathological nystagmus is a spontaneous oscillation of the eyes. It is a complex problem with many subtypes and causes ranging from the acute neurological emergency to chronic visual disorders. There is considerable variability in clinical management and patient experience across the UK. The Nystagmus Care Pathway (NCP) is a proposal to provide an evidence-based, consistent minimum standard of care across all eye services for patients with nystagmus. The NCP coordinates expertise from the various team members with a staged approach: 1) pathway entry; 2) nystagmus identification; 3) finding underlying causes/associations; 4) managing causes/associations; 5) managing the nystagmus and its effects; 6) support for patients and families; 7) pathway exit. Orthoptists are ideally placed to coordinate the NCP as they are trained in ocular motility and visual assessment. They are accustomed to providing continuity of care, multidisciplinary working and via the British and Irish Orthoptic Society (BIOS), they can provide consistency of care across the UK. Key performance indicators are proposed.

12.
Gen Comp Endocrinol ; 270: 123-130, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30392885

RESUMO

The production of high quality secondary sexual traits can be constrained by trade-offs in the allocation of energy and nutrients with other metabolic activities, and is mediated by physiological processes. In birds, the factors influencing male plumage quality have been well studied; however, factors affecting female plumage quality are poorly understood. Furthermore, it remains uncertain which physiological traits mediate the relationship between body condition and ornaments. In this three-year study of after-second-year female tree swallows (Tachycineta bicolor), we investigated (1) the relationship between baseline corticosterone near the end of the brood-rearing period (CORTBR) and feather colour characteristics (hue, saturation, brightness) the following year, and (2) the relationship between baseline corticosterone measured during incubation (CORTI) and brood rearing (CORTBR), and feather colour in the same year. To control for reproductive effort, we included reproductive parameters as covariates in all analyses. In this first study between CORT and the plumage colour characteristics of a species bearing iridescent feathers, we did not find any relationship between CORTBR and the colour of subsequently-produced feathers, nor did we find any relationship between CORT and the colour of feathers displayed during that breeding season. If CORT levels at the end of breeding carry over to influence the immediately subsequent moult period as we expect, our results generally indicate that structural plumage quality may not be as sensitive to circulating CORT levels compared to carotenoid-based colouration. Future studies, particularly those employing experimental manipulations of CORT during moult in species with iridescent traits, are necessary to fully determine the role glucocorticoids play in mediating the quality of secondary sexual characteristics.


Assuntos
Corticosterona/metabolismo , Plumas/metabolismo , Animais , Feminino , Masculino , Andorinhas
13.
J Med Chem ; 61(24): 11074-11100, 2018 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-30384606

RESUMO

A HTS campaign identified compound 1, an excellent hit-like molecule to initiate medicinal chemistry efforts to optimize a dual ROCK1 and ROCK2 inhibitor. Substitution (2-Cl, 2-NH2, 2-F, 3-F) of the pyridine hinge binding motif or replacement with pyrimidine afforded compounds with a clean CYP inhibition profile. Cocrystal structures of an early lead compound were obtained in PKA, ROCK1, and ROCK2. This provided critical structural information for medicinal chemistry to drive compound design. The structural data indicated the preferred configuration at the central benzylic carbon would be ( R), and application of this information to compound design resulted in compound 16. This compound was shown to be a potent and selective dual ROCK inhibitor in both enzyme and cell assays and efficacious in the retinal nerve fiber layer model after oral dosing. This tool compound has been made available through the AbbVie Compound Toolbox. Finally, the cocrystal structures also identified that aspartic acid residues 176 and 218 in ROCK2, which are glutamic acids in PKA, could be targeted as residues to drive both potency and kinome selectivity. Introduction of a piperidin-3-ylmethanamine group to the compound series resulted in compound 58, a potent and selective dual ROCK inhibitor with excellent predicted drug-like properties.


Assuntos
Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Quinases Associadas a rho/antagonistas & inibidores , Administração Oral , Animais , Disponibilidade Biológica , Cristalografia por Raios X , Inibidores do Citocromo P-450 CYP2C9/química , Inibidores do Citocromo P-450 CYP2C9/farmacologia , Inibidores do Citocromo P-450 CYP3A/química , Inibidores do Citocromo P-450 CYP3A/farmacologia , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Meia-Vida , Humanos , Camundongos Endogâmicos C57BL , Traumatismos do Nervo Óptico/tratamento farmacológico , Traumatismos do Nervo Óptico/patologia , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Quinases Associadas a rho/química
14.
SLAS Discov ; 23(10): 1040-1050, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29991334

RESUMO

In vitro analysis of covalent inhibitors requires special consideration, due to the time-dependent and typically irreversible nature of their target interaction. While many analyses are reported for the characterization of a final candidate, it is less clear which are most useful in the lead optimization phase of drug discovery. In the context of identifying covalent inhibitors of Bruton's tyrosine kinase (BTK), we evaluated multiple techniques for characterizing covalent inhibitors. Several methods qualitatively support the covalent mechanism of action or support a particular aspect of interaction but were not otherwise informative to differentiate inhibitors. These include the time dependence of IC50, substrate competition, mass spectrometry, and recovery of function after inhibitor removal at the biochemical and cellular level. A change in IC50 upon mutation of the targeted BTK C481 nucleophile or upon removal of the electrophilic moiety of the inhibitor was not always a reliable indicator of covalent inhibition. Determination of kinact and KI provides a quantitative description of covalent interactions but was challenging at scale and frequently failed to provide more than the ratio of the two values, kinact/KI. Overall, a combination of approaches is required to assess time-dependent, covalent, and irreversible inhibitors in a manner suitable to reliably advance drug candidates.


Assuntos
Tirosina Quinase da Agamaglobulinemia/antagonistas & inibidores , Descoberta de Drogas , Inibidores de Proteínas Quinases/farmacologia , Tirosina Quinase da Agamaglobulinemia/química , Tirosina Quinase da Agamaglobulinemia/metabolismo , Animais , Relação Dose-Resposta a Droga , Descoberta de Drogas/métodos , Ativação Enzimática/efeitos dos fármacos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Espectrometria de Massas , Inibidores de Proteínas Quinases/química , Proteínas Recombinantes
15.
Oecologia ; 183(4): 987-996, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28214946

RESUMO

Feather corticosterone (CORT) levels are increasingly employed as biomarkers of environmental stress. However, it is unclear if feather CORT levels reflect stress and/or workload in the wild. We investigated whether feather CORT represents a biomarker of environmental stress and reproductive effort in tree swallows (Tachycineta bicolor). Specifically, we examined whether individual state and investment during reproduction could predict feather CORT levels in subsequently moulted feathers and whether those levels could predict future survival and reproductive success. Through a manipulation of flight cost during breeding, we also investigated whether an increase in stress level would be reflected in subsequently grown feathers, and whether those levels could predict future success. We found that CORT levels of feathers grown during moult did not (1) reflect past breeding experience (n = 29), (2) predict reproductive output (n = 18), or (3) respond to a manipulation of flight effort during reproduction (10 experimental, 14 control females). While higher feather CORT levels predicted higher return rate (a proxy for survival), they did so only in the manipulated group (n = 36), and this relationship was opposite to expected. Overall, our results add to the mixed literature reporting that feather CORT levels can be positively, negatively, or not related to proxies of within-season and longer-term fitness (i.e., carryover effects). In addition, our results indicate that CORT levels or disturbances experienced during one time (e.g., breeding) may not carry over to subsequent stages (e.g., moult). We, therefore, petition for directed research investigating whether feather CORT represents exposure to chronic stress in feathers grown during moult.


Assuntos
Corticosterona , Plumas , Animais , Biomarcadores , Cruzamento , Muda , Reprodução
16.
Invest Ophthalmol Vis Sci ; 58(1): 642-650, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28129427

RESUMO

Purpose: Most individuals with infantile nystagmus (IN) have an idiosyncratic gaze angle at which their nystagmus intensity is minimized. Some adopt an abnormal head posture to use this "null zone," and it has therefore long been assumed that this provides people with nystagmus with improved visual acuity (VA). However, recent studies suggest that improving the nystagmus waveform could have little, if any, influence on VA; that is, VA is fundamentally limited in IN. Here, we examined the impact of the null zone on VA. Methods: Visual acuity was measured in eight adults with IN using a psychophysical staircase procedure with reversals at three horizontal gaze angles, including the null zone. Results: As expected, changes in gaze angle affected nystagmus amplitude, frequency, foveation duration, and variability of intercycle foveation position. Across participants, each parameter (except frequency) was significantly correlated with VA. Within any given individual, there was a small but significant improvement in VA (0.08 logMAR) at the null zone as compared with the other gaze angles tested. Despite this, no change in any of the nystagmus waveform parameters was significantly associated with changes in VA within individuals. Conclusions: A strong relationship between VA and nystagmus characteristics exists between individuals with IN. Although significant, the improvement in VA observed within individuals at the null zone is much smaller than might be expected from the occasionally large variations in intensity and foveation dynamics (and anecdotal patient reports of improved vision), suggesting that improvement of other aspects of visual performance may also encourage use of the null zone.


Assuntos
Adaptação Ocular/fisiologia , Movimentos Oculares/fisiologia , Nistagmo Congênito/fisiopatologia , Músculos Oculomotores/fisiopatologia , Acuidade Visual/fisiologia , Adulto , Técnicas de Diagnóstico Oftalmológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nistagmo Congênito/diagnóstico , Músculos Oculomotores/diagnóstico por imagem , Postura , Adulto Jovem
17.
Conserv Physiol ; 4(1): cow051, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27933163

RESUMO

The measurement of corticosterone (CORT) levels in feathers has recently become an appealing tool for the conservation toolbox, potentially providing a non-invasive, integrated measure of stress activity throughout the time of feather growth. However, because the mechanism of CORT deposition, storage and stability in feathers is not fully understood, it is unclear how reliable this measure may be, especially when there is an extended interval between growth and feather collection. We compared CORT levels of naturally grown feathers from tree swallows (Tachycineta bicolor) that were moulted and regrown concurrently and therefore expected to have similar CORT levels. Specifically, we compared the same feather from the left and right wing (moulted symmetrically) and different types of feathers (wing, back and tail) expected to have been moulted within the same time period. We found that larger, heavier feathers held more CORT per unit length. In addition, we found a lack of concordance in CORT levels both within the same feather type and between different feather types, even after taking into account differences in feather density. Our results indicate that naturally grown feathers may not consistently provide an indication of stress status. Additionally, conflict in results may arise depending on the feather assayed, and total feather volume may be an important consideration when interpreting feather CORT levels. Future work is necessary to determine explicitly the mechanisms of CORT deposition, the effects of environmental exposure and feather wear on the permanence of the feather CORT signal, and the influence of responses to wild stressors on feather CORT levels, before feather CORT can be implemented effectively as a tool for ecological and conservation applications.

18.
J Pharmacol Exp Ther ; 359(1): 151-8, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27519818

RESUMO

Inhibition of the sphingosine-1-phosphate (S1P)-catabolizing enzyme S1P lyase (S1PL) elevates the native ligand of S1P receptors and provides an alternative mechanism for immune suppression to synthetic S1P receptor agonists. S1PL inhibition is reported to preferentially elevate S1P in lymphoid organs. Tissue selectivity could potentially differentiate S1PL inhibitors from S1P receptor agonists, the use of which also results in bradycardia, atrioventricular block, and hypertension. But it is unknown if S1PL inhibition would also modulate cardiac S1P levels or cardiovascular function. The S1PL inhibitor 6-[(2R)-4-(4-benzyl-7-chlorophthalazin-1-yl)-2-methylpiperazin-1-yl]pyridine-3-carbonitrile was used to determine the relationship in rats between drug concentration, S1P levels in select tissues, and circulating lymphocytes. Repeated oral doses of the S1PL inhibitor fully depleted circulating lymphocytes after 3 to 4 days of treatment in rats. Full lymphopenia corresponded to increased levels of S1P of 100- to 1000-fold in lymph nodes, 3-fold in blood (but with no change in plasma), and 9-fold in cardiac tissue. Repeated oral dosing of the S1PL inhibitor in telemeterized, conscious rats resulted in significant bradycardia within 48 hours of drug treatment, comparable in magnitude to the bradycardia induced by 3 mg/kg fingolimod. These results suggest that S1PL inhibition modulates cardiac function and does not provide immune suppression with an improved cardiovascular safety profile over fingolimod in rats.


Assuntos
Aldeído Liases/antagonistas & inibidores , Bradicardia/induzido quimicamente , Inibidores Enzimáticos/efeitos adversos , Coração/efeitos dos fármacos , Lisofosfolipídeos/metabolismo , Miocárdio/metabolismo , Esfingosina/análogos & derivados , Animais , Bradicardia/metabolismo , Relação Dose-Resposta a Droga , Feminino , Coração/fisiologia , Masculino , Piperazinas/efeitos adversos , Ratos , Ratos Sprague-Dawley , Esfingosina/metabolismo
19.
Toxicol Pathol ; 44(7): 998-1012, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27324990

RESUMO

Spleen tyrosine kinase (Syk) is a nonreceptor tyrosine kinase that is an important signaling enzyme downstream of immunoreceptors containing an intracellular immunoreceptor tyrosine activating motif (ITAM). These receptors encompass a wide variety of biological functions involved in autoimmune disease pathogenesis. There has been considerable interest in the development of inhibitors of the Syk pathway for the treatment of rheumatoid arthritis and systemic lupus erythematosus. We report that Syk inhibition mechanistically caused peri-islet hemorrhages and fibrin deposition in the rat pancreas and that this finding is due to a homeostatic functional defect in platelets. In more limited studies, similar lesions could not be induced in mice, dogs, and cynomolgus monkeys at similar or higher plasma drug concentrations. Irradiation-induced thrombocytopenia caused a phenotypically similar peri-islet pancreas lesion and the formation of this lesion could be prevented by platelet transfusion. In addition, Syk inhibitor-induced lesions were prevented by the coadministration of prednisone. A relatively greater sensitivity of rat platelets to Syk inhibition was supported by functional analyses demonstrating rat-specific differences in response to convulxin, a glycoprotein VI agonist that signals through Syk. These data demonstrate that the Syk pathway is critical in platelet-endothelial cell homeostasis in the peri-islet pancreatic microvasculature in rats.


Assuntos
Plaquetas/metabolismo , Inibidores Enzimáticos/toxicidade , Hemorragia/induzido quimicamente , Ilhotas Pancreáticas/efeitos dos fármacos , Quinase Syk/antagonistas & inibidores , Animais , Plaquetas/efeitos dos fármacos , Cães , Ilhotas Pancreáticas/patologia , Macaca fascicularis , Camundongos , Ratos , Ratos Sprague-Dawley , Especificidade da Espécie
20.
Bioorg Med Chem Lett ; 26(9): 2293-6, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-27013389

RESUMO

S1P Lyase (SPL) has been described as a drug target in the treatment of autoimmune diseases. It plays an important role in maintaining intracellular levels of S1P thereby affecting T cell egress from lymphoid tissues. Several groups have already published approaches to inhibit S1P Lyase with small molecules, which in turn increase endogenous S1P concentrations resulting in immunosuppression. The use of structural biology has previously aided SPL inhibitor design. Novel construct design is at times necessary to provide a reagent for protein crystallography. Here we present a chimeric bacterial protein scaffold used for protein X-ray structures in the presence of early small molecule inhibitors. Mutations were introduced to the bacterial SPL from Symbiobacterium thermophilum which mimic the human enzyme. As a result, two mutant StSPL crystal structures resolved to 2.8Å and 2.2Å resolutions were solved and provide initial structural hypotheses for an isoxazole chemical series, whose optimization is discussed in the accompanying paper.


Assuntos
Aldeído Liases/metabolismo , Desenho de Fármacos , Escherichia coli/enzimologia , Aldeído Liases/química , Cristalografia por Raios X
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