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1.
JAMIA Open ; 7(3): ooae048, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38978714

RESUMO

Introduction: The Pediatric Surviving Sepsis Campaign supports the implementation of automated tools for early sepsis recognition. In 2019 the C.S. Mott Children's Hospital Pediatric Intensive Care Unit deployed an electronic medical record (EMR)-based screening for early recognition and treatment of sepsis. Materials and Methods: We analyzed all automated primary sepsis alerts, secondary screens, and bedside huddles from November 2019 to January 2020 (Cohort 1) and from November 2020 to January 2021 (Cohort 2) to identify barriers and facilitators for the use of this tool. We distributed surveys to frontline providers to gather feedback on end-user experience. Results: In Cohort 1, 895 primary alerts were triggered, yielding 503 completed secondary screens and 40 bedside huddles. In Cohort 2, 925 primary alerts were triggered, yielding 532 completed secondary screens and 12 bedside huddles. Surveys assessing end-user experience identified the following facilitators: (1) 73% of nurses endorsed the bedside huddle as value added; (2) 74% of medical providers agreed the bedside huddle increased the likelihood of interventions. The greatest barriers to successful implementation included the (1) overall large number of primary alerts from the automated tool and (2) rate of false alerts, many due to routine respiratory therapy interventions. Discussion: Our data suggests that the successful implementation of EMR-based sepsis screening tools requires countermeasures focusing on 3 key drivers for change: education, technology, and patient safety. Conclusion: While both medical providers and bedside nurses found merit in our EMR-based sepsis early recognition system, continued refinement is necessary to avoid sepsis alert fatigue.

2.
Pharmaceutics ; 16(5)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38794254

RESUMO

The movement of organic anionic drugs across cell membranes is partly governed by interactions with SLC and ABC transporters in the intestine, liver, kidney, blood-brain barrier, placenta, breast, and other tissues. Major transporters involved include organic anion transporters (OATs, SLC22 family), organic anion transporting polypeptides (OATPs, SLCO family), and multidrug resistance proteins (MRPs, ABCC family). However, the sets of molecular properties of drugs that are necessary for interactions with OATs (OAT1, OAT3) vs. OATPs (OATP1B1, OATP1B3) vs. MRPs (MRP2, MRP4) are not well-understood. Defining these molecular properties is necessary for a better understanding of drug and metabolite handling across the gut-liver-kidney axis, gut-brain axis, and other multi-organ axes. It is also useful for tissue targeting of small molecule drugs and predicting drug-drug interactions and drug-metabolite interactions. Here, we curated a database of drugs shown to interact with these transporters in vitro and used chemoinformatic approaches to describe their molecular properties. We then sought to define sets of molecular properties that distinguish drugs interacting with OATs, OATPs, and MRPs in binary classifications using machine learning and artificial intelligence approaches. We identified sets of key molecular properties (e.g., rotatable bond count, lipophilicity, number of ringed structures) for classifying OATs vs. MRPs and OATs vs. OATPs. However, sets of molecular properties differentiating OATP vs. MRP substrates were less evident, as drugs interacting with MRP2 and MRP4 do not form a tight group owing to differing hydrophobicity and molecular complexity for interactions with the two transporters. If the results also hold for endogenous metabolites, they may deepen our knowledge of organ crosstalk, as described in the Remote Sensing and Signaling Theory. The results also provide a molecular basis for understanding how small organic molecules differentially interact with OATs, OATPs, and MRPs.

3.
J Family Med Prim Care ; 13(2): 613-618, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38605798

RESUMO

Introduction: The AST/platelet ratio index (APRI) is a well-researched indicator of liver fibrosis. Some studies have shown that APRI can be used as a predictor of severe dengue, but the data is limited. As dengue epidemics are common in our country with limited healthcare resources, we believe APRI can help emergency physicians/primary physicians in predicting the severity of dengue and plan for the appropriate use of limited healthcare resources. Objective: 1) To determine the utility of APRI as a predictor of severe dengue. 2) To determine the association of APRI with length of hospital stay and platelet requirement. Materials and Methods: A retrospective cross-sectional study was done on patients presented to the Emergency Medicine department at Travancore Medicity Medical College with a positive Dengue NS1 antigen or IgM antibody. Results: We found from the univariate analysis results that ALT > 74.5 IU/L has a sensitivity of 59.6 and a specificity of 76.3 (AUC: 0.696; 95% CI: 0.606-0.786), AST > 160.5 IU/L has a sensitivity of 42.3 and a specificity of 93.7 (AUC: 0.747; 95% CI: 0.665-0.829), and APRI > 3.2 has a sensitivity of 69.2 and a specificity of 84.2 (AUC: 0.806; 95% CI: 0.72-0.884) to predict severe dengue. Patients with an APRI of >3.2 required a mean hospital stay of 5.47 days (P = 0.005); 27 (81.8%) requiring platelet transfusion had an APRI of > 3.2 (P = 0.00). Conclusion: APRI is a straightforward index that can be easily derived from AST and platelet values. APRI values of >3.2 can predict severe dengue with a sensitivity of 69.2 and a specificity of 84.2. APRI values of >3.2 are also associated with the length of hospital stay and requirement of platelet transfusion.

4.
Cureus ; 16(3): e56379, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38633929

RESUMO

Acute ischemic stroke (AIS) affecting the posterior cerebral artery (PCA) represents a unique clinical challenge, necessitating a multifaceted approach to rehabilitation. This review aims to provide a comprehensive overview of physiotherapeutic interventions tailored specifically for individuals with AIS involving the PCA territory. The PCA supplies critical areas of the brain responsible for visual processing, memory, and sensory integration. Consequently, patients with PCA infarcts often exhibit a distinct set of neurological deficits, including visual field disturbances, cognitive impairments, and sensory abnormalities. This case report highlights evidence-based physiotherapy strategies that encompass a spectrum of interventions, ranging from early mobilization and motor training to sensory reintegration and cognitive rehabilitation. Early mobilization, including bed mobility exercises and upright activities, is crucial to prevent complications associated with immobility. Motor training interventions target the restoration of functional movement patterns, addressing hemiparesis and balance impairments.

5.
Pharmaceutics ; 13(10)2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34684013

RESUMO

In patients with liver or kidney disease, it is especially important to consider the routes of metabolism and elimination of small-molecule pharmaceuticals. Once in the blood, numerous drugs are taken up by the liver for metabolism and/or biliary elimination, or by the kidney for renal elimination. Many common drugs are organic anions. The major liver uptake transporters for organic anion drugs are organic anion transporter polypeptides (OATP1B1 or SLCO1B1; OATP1B3 or SLCO1B3), whereas in the kidney they are organic anion transporters (OAT1 or SLC22A6; OAT3 or SLC22A8). Since these particular OATPs are overwhelmingly found in the liver but not the kidney, and these OATs are overwhelmingly found in the kidney but not liver, it is possible to use chemoinformatics, machine learning (ML) and deep learning to analyze liver OATP-transported drugs versus kidney OAT-transported drugs. Our analysis of >30 quantitative physicochemical properties of OATP- and OAT-interacting drugs revealed eight properties that in combination, indicate a high propensity for interaction with "liver" transporters versus "kidney" ones based on machine learning (e.g., random forest, k-nearest neighbors) and deep-learning classification algorithms. Liver OATPs preferred drugs with greater hydrophobicity, higher complexity, and more ringed structures whereas kidney OATs preferred more polar drugs with more carboxyl groups. The results provide a strong molecular basis for tissue-specific targeting strategies, understanding drug-drug interactions as well as drug-metabolite interactions, and suggest a strategy for how drugs with comparable efficacy might be chosen in chronic liver or kidney disease (CKD) to minimize toxicity.

6.
Am J Pharm Educ ; 85(5): 8311, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-34283730

RESUMO

As a result of restrictions imposed by COVID-19, many researchers have responded to the call for remote, advanced pharmacy practice experiences (APPEs) that do not involve direct patient care. The influx of materials on online pedagogy may be difficult for new preceptors to digest while familiarizing themselves with the APPE program. To complement the available guidance on remote learning for new preceptors, we describe our experiences with implementing a remote, research-focused APPE during COVID-19. Common challenges are discussed and potential solutions that may help new preceptors anticipate and overcome barriers to achieving the educational outcomes of research-focused APPE are proposed.


Assuntos
COVID-19/epidemiologia , Educação em Farmácia/organização & administração , Pesquisa em Farmácia/organização & administração , Preceptoria/organização & administração , Currículo , Humanos , Pandemias , Aprendizagem Baseada em Problemas , Estudantes de Farmácia
7.
JBI Evid Synth ; 19(11): 3129-3141, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34054037

RESUMO

OBJECTIVE: The objective of this review is to summarize observational research methods employed to study fracture risk and the use of type 2 diabetes mellitus medications. The methods summary will be used as a case study to illustrate current practices in the study of medication effects on fracture risk. INTRODUCTION: Observational studies examining drug effects on fracture risk fill knowledge gaps left by clinical trials but require specific design considerations. In recent years, several pharmacoepidemiologic studies have examined fracture risk as a possible adverse effect of type 2 diabetes mellitus medications using varying methodologies; these studies can illustrate design considerations for studies of fracture risk. INCLUSION CRITERIA: This scoping review will consider peer-reviewed observational studies that examine the effects of type 2 diabetes mellitus medications on fracture risk. Primary literature comprising empirical pharmacoepidemiologic studies, such as cohort, case-control, case-crossover, self-controlled, case series, and case-cohort designs, that evaluate fracture risk associated with at least one type 2 diabetes mellitus medication will be eligible. Studies without use of an administrative database and those with an experimental, cross-sectional, or time-series design will be excluded. METHODS: This scoping review will follow JBI methodology for scoping reviews. MEDLINE (Ovid), Embase (Ovid), and CINAHL Plus with Full Text (EBSCO) will be searched from January 1, 2000 (to capture recent methodologies) to the present to identify eligible articles. After de-duplication, titles and abstracts will be screened independently by two reviewers, then full texts will be reviewed. Data on study methods will be extracted from eligible texts using a piloted form developed by the authors, and study methods will be aggregated in tabular format.


Assuntos
Diabetes Mellitus Tipo 2 , Envio de Mensagens de Texto , Estudos Transversais , Atenção à Saúde , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , Humanos , Estudos Observacionais como Assunto , Projetos de Pesquisa , Literatura de Revisão como Assunto
8.
J Biol Chem ; 296: 100603, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33785360

RESUMO

Organic anion transporter 1 (OAT1/SLC22A6) is a drug transporter with numerous xenobiotic and endogenous substrates. The Remote Sensing and Signaling Theory suggests that drug transporters with compatible ligand preferences can play a role in "organ crosstalk," mediating overall organismal communication. Other drug transporters are well known to transport lipids, but surprisingly little is known about the role of OAT1 in lipid metabolism. To explore this subject, we constructed a genome-scale metabolic model using omics data from the Oat1 knockout mouse. The model implicated OAT1 in the regulation of many classes of lipids, including fatty acids, bile acids, and prostaglandins. Accordingly, serum metabolomics of Oat1 knockout mice revealed increased polyunsaturated fatty acids, diacylglycerols, and long-chain fatty acids and decreased ceramides and bile acids when compared with wildtype controls. Some aged knockout mice also displayed increased lipid droplets in the liver when compared with wildtype mice. Chemoinformatics and machine learning analyses of these altered lipids defined molecular properties that form the structural basis for lipid-transporter interactions, including the number of rings, positive charge/volume, and complexity of the lipids. Finally, we obtained targeted serum metabolomics data after short-term treatment of rodents with the OAT-inhibiting drug probenecid to identify potential drug-metabolite interactions. The treatment resulted in alterations in eicosanoids and fatty acids, further supporting our metabolic reconstruction predictions. Consistent with the Remote Sensing and Signaling Theory, the data support a role of OAT1 in systemic lipid metabolism.


Assuntos
Metabolismo dos Lipídeos , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Animais , Técnicas de Inativação de Genes , Genômica , Aprendizado de Máquina , Camundongos , Proteína 1 Transportadora de Ânions Orgânicos/deficiência , Proteína 1 Transportadora de Ânions Orgânicos/genética
9.
J Biol Chem ; 295(7): 1829-1842, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-31896576

RESUMO

The multispecific organic anion transporters, OAT1 (SLC22A6) and OAT3 (SLC22A8), the main kidney elimination pathways for many common drugs, are often considered to have largely-redundant roles. However, whereas examination of metabolomics data from Oat-knockout mice (Oat1 and Oat3KO) revealed considerable overlap, over a hundred metabolites were increased in the plasma of one or the other of these knockout mice. Many of these relatively unique metabolites are components of distinct biochemical and signaling pathways, including those involving amino acids, lipids, bile acids, and uremic toxins. Cheminformatics, together with a "logical" statistical and machine learning-based approach, identified a number of molecular features distinguishing these unique endogenous substrates. Compared with OAT1, OAT3 tends to interact with more complex substrates possessing more rings and chiral centers. An independent "brute force" approach, analyzing all possible combinations of molecular features, supported the logical approach. Together, the results suggest the potential molecular basis by which OAT1 and OAT3 modulate distinct metabolic and signaling pathways in vivo As suggested by the Remote Sensing and Signaling Theory, the analysis provides a potential mechanism by which "multispecific" kidney proximal tubule transporters exert distinct physiological effects. Furthermore, a strong metabolite-based machine-learning classifier was able to successfully predict unique OAT1 versus OAT3 drugs; this suggests the feasibility of drug design based on knockout metabolomics of drug transporters. The approach can be applied to other SLC and ATP-binding cassette drug transporters to define their nonredundant physiological roles and for analyzing the potential impact of drug-metabolite interactions.


Assuntos
Metabolômica , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Toxinas Biológicas/metabolismo , Trifosfato de Adenosina/genética , Animais , Ácidos e Sais Biliares/metabolismo , Transporte Biológico/genética , Humanos , Inativação Metabólica/genética , Túbulos Renais Proximais/metabolismo , Aprendizado de Máquina , Camundongos , Camundongos Knockout , Proteína 1 Transportadora de Ânions Orgânicos/genética , Transportadores de Ânions Orgânicos/genética , Transportadores de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/genética , Transdução de Sinais
10.
Indian J Pharmacol ; 47(6): 687-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26729967

RESUMO

Drug reaction with eosinophilia and systemic symptoms (DRESS) or drug hypersensitivity syndrome is considered as a severe cutaneous adverse drug reaction which is most commonly precipitated by aromatic anticonvulsants, lamotrigine, dapsone, allopurinol, minocycline, and salazopyrin. Its clinical manifestations are often variable. On rare occasions, it can present with only systemic involvement without any cutaneous features. A complete drug history is of paramount importance in making an early diagnosis. We report the case of a male patient who presented with fever, lymphadenopathy, hepatosplenomegaly, and hepatitis, 2 weeks after starting salazopyrin. The presence of atypical lymphocytes in the peripheral smear was indicative of a viral infection or a hematological dyscrasia. Bone marrow examination revealed a normocellular marrow with an increase in eosinophil precursors. Investigations for the common causes for fever and hepatitis were negative. The presence of eosinophilia, the temporal relationship of the symptoms with the initiation of treatment with salazopyrin, and the marked improvement on withdrawal of the drug along with the administration of systemic corticosteroids, were features consistent with the diagnosis of DRESS. With the incidence of this condition showing a rising trend, it is important for the clinician to be aware of its variable manifestations, as a delay in diagnosis and treatment can be fatal.


Assuntos
Anti-Inflamatórios não Esteroides/efeitos adversos , Síndrome de Hipersensibilidade a Medicamentos/diagnóstico , Sulfassalazina/efeitos adversos , Adulto , Anti-Inflamatórios/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Artrite Reativa/tratamento farmacológico , Diagnóstico Diferencial , Síndrome de Hipersensibilidade a Medicamentos/tratamento farmacológico , Síndrome de Hipersensibilidade a Medicamentos/fisiopatologia , Quimioterapia Combinada/efeitos adversos , Humanos , Articulação do Joelho , Masculino , Prednisolona/uso terapêutico , Índice de Gravidade de Doença , Sulfassalazina/uso terapêutico , Resultado do Tratamento
12.
PLoS One ; 6(9): e25587, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21980496

RESUMO

BACKGROUND: Hepatic steatosis is an established risk factor for complications following major hepatic resection. Pharmacological options to reverse steatosis prior to surgery, however, are lacking. We hypothesized that treatment with the pharmacologic tumor necrosis factor-α converting enzyme (TACE)-inhibitor Marimastat would reverse established steatosis, leading to improved outcome following hepatectomy. METHODOLOGY/PRINCIPAL FINDINGS: C57BL/6 male mice were fed a high fat diet for 9 weeks to establish obesity, hepatic steatosis and insulin resistance, and were administered either Marimastat or vehicle for an additional 2 or 4 weeks. Leptin deficient, hyperinsulinemic ob/ob mice were treated with Marimastat for 4 weeks. Hepatic steatosis was quantified by magnetic resonance spectroscopy and confirmed by histology. After two weeks, Marimastat-treated animals significantly improved surrogate markers for insulin sensitivity and liver histology, and experienced a 66% decrease in steatosis (P = 0.010). These findings were confirmed in ob/ob mice. Transcripts related to fatty acid synthesis were significantly downregulated in Marimastat-treated animals. Following pre-treatment with Marimastat or vehicle for two weeks, high fat fed C57BL/6 mice were subjected to two-thirds hepatectomy. Post-operative liver injury as quantified by serum aspartate aminotransferase levels and alanine aminotransferase levels was significantly decreased by 57% (P = 0.020) and 44% (P = 0.032) respectively, compared to controls. CONCLUSION/SIGNIFICANCE: Treatment with the TACE-inhibitor Marimastat improved surrogate markers for insulin sensitivity and reversed steatosis in mouse models of diet-induced obesity and leptin deficiency, thereby attenuating post-operative injury following hepatectomy. This may suggest a potential therapeutic role in patients with fatty liver disease; especially those who need to undergo hepatic resection.


Assuntos
Proteínas ADAM/antagonistas & inibidores , Fígado Gorduroso/metabolismo , Fígado Gorduroso/cirurgia , Ácidos Hidroxâmicos/farmacologia , Insulina/metabolismo , Inibidores de Proteases/farmacologia , Proteínas ADAM/metabolismo , Proteína ADAM17 , Adipocinas/sangue , Animais , Biomarcadores/metabolismo , Dieta Hiperlipídica/efeitos adversos , Ácidos Graxos/metabolismo , Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/patologia , Retroalimentação Fisiológica/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Hepatectomia/efeitos adversos , Ácidos Hidroxâmicos/uso terapêutico , Resistência à Insulina , Leptina/deficiência , Fígado/efeitos dos fármacos , Fígado/lesões , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/tratamento farmacológico , Obesidade/etiologia , Obesidade/metabolismo , Obesidade/patologia , Inibidores de Proteases/uso terapêutico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fatores de Tempo , Inibidor Tecidual de Metaloproteinase-3/metabolismo , Resultado do Tratamento
13.
Gastroenterology ; 140(5): 1642-52, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21277850

RESUMO

BACKGROUND & AIMS: The ubiquitous cross-linking enzyme tissue transglutaminase (TG2) has been implicated in irreversible collagen stabilization in liver fibrosis, although functional evidence is lacking. We studied the contribution of TG2 to hepatic fibrotic matrix stability, as well as liver fibrosis progression and regression in TG2-deficient mice. METHODS: Advanced liver fibrosis was induced by carbon tetrachloride or thioacetamide in TG2(-/-) mice and their wild-type littermates to study fibrosis progression and its spontaneous regression for up to 36 weeks. Pattern and extent of fibrosis were analyzed by histology and hepatic hydroxyproline quantification. Dynamic changes in hepatic matrix cross-linking were assessed by stepwise collagen extraction. Expression of 7 TGs and fibrosis-related genes was determined by quantitative reverse-transcription polymerase chain reaction. RESULTS: Transglutaminase activity was increased in fibrosis, and the level of TG2 messenger RNA correlated with the expression of fibrosis-related genes. Biochemical analysis revealed progressive collagen stabilization, with an up to 6-fold increase in the highly cross-linked, pepsin-insoluble fraction (26%). In TG2(-/-) mice, hepatic TG activity was significantly decreased, but chronic administration of carbon tetrachloride or thioacetamide led to a comparable extent and pattern of liver fibrosis, as in wild-type mice. In TG2(-/-) mice, the composition of hepatic collagen fractions and levels of fibrosis-related transcripts were unchanged, and fibrosis reversal was not facilitated. CONCLUSIONS: TG2 and TG activity are up-regulated during hepatic fibrosis progression, but do not contribute to fibrogenesis or stabilization of the collagen matrix. TG2 deletion does not promote regression of liver fibrosis. TG2-independent collagen cross-linking is a remarkable feature of progressing hepatic fibrosis and represents an important therapeutic target for liver fibrosis.


Assuntos
Proteínas de Ligação ao GTP/genética , Regulação da Expressão Gênica , Cirrose Hepática Experimental/enzimologia , Fígado/patologia , RNA/genética , Transglutaminases/genética , Animais , Apoptose/genética , Progressão da Doença , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Proteínas de Ligação ao GTP/biossíntese , Fígado/enzimologia , Cirrose Hepática Experimental/genética , Cirrose Hepática Experimental/patologia , Camundongos , Camundongos Endogâmicos C57BL , Proteína 2 Glutamina gama-Glutamiltransferase , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transglutaminases/biossíntese
14.
Am J Physiol Gastrointest Liver Physiol ; 298(3): G323-34, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20056896

RESUMO

Studies have suggested the reversibility of liver fibrosis, but the mechanisms of fibrosis reversal are poorly understood. We investigated the possible functional link between apoptosis, macrophages, and matrix turnover in rat liver during reversal of fibrosis secondary to bile duct ligation (BDL). Biliary fibrosis was induced by BDL for 4 wk. After Roux-en-Y (RY)-bilio-jejunal-anastomosis, resolution of fibrosis was monitored for up to 12 wk by hepatic collagen content, matrix metalloproteinase (MMP) expression and activities, and fibrosis-related gene expression. MMP expression and activities were studied in macrophages after engulfment of apoptotic cholangiocytes in vitro. Hepatic collagen decreased to near normal at 12 wk after RY-anastomosis. During reversal, profibrogenic mRNA declined, whereas expression of several profibrolytic MMPs increased. Fibrotic septa showed fragmentation at week 4 and disappeared at week 12. Peak histological remodeling at week 4 was characterized by massive apoptosis of cytokeratin 19+ cholangiocytes, >90% in colocalization with CD68+ macrophages, and a 2- to 7.5-fold increase in matrix-degrading activities. In vitro, phagocytosis of apoptotic cholangiocytes induced matrix-degrading activities and MMP-3, -8, and -9 in rat peritoneal macrophages. We concluded that reconstruction of bile flow after BDL leads to an orchestrated fibrolytic program that results in near complete reversal of advanced fibrosis. The peak of connective tissue remodeling and fibrolytic activity is associated with massive apoptosis of cholangiocytes and their phagocytic clearance by macrophages in vivo. Macrophages upregulate MMPs and become fibrolytic effector cells upon apoptotic cholangiocyte engulfment in vitro, suggesting that phagocytosis-associated MMP induction in macrophages significantly contributes to biliary fibrosis reversal.


Assuntos
Apoptose/fisiologia , Ductos Biliares Intra-Hepáticos/patologia , Cirrose Hepática Biliar/patologia , Cirrose Hepática Experimental/patologia , Macrófagos/fisiologia , Fagocitose/fisiologia , Anastomose em-Y de Roux , Animais , Ductos Biliares Extra-Hepáticos/cirurgia , Linhagem Celular , Movimento Celular/fisiologia , Células Cultivadas , Colágeno/metabolismo , Colágeno Tipo I/genética , Cadeia alfa 1 do Colágeno Tipo I , Colagenases/metabolismo , Regulação para Baixo/genética , Gelatinases/metabolismo , Expressão Gênica/genética , Cadeias beta de Integrinas/genética , Ligadura , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática Biliar/metabolismo , Cirrose Hepática Biliar/cirurgia , Cirrose Hepática Experimental/metabolismo , Cirrose Hepática Experimental/cirurgia , Macrófagos/enzimologia , Macrófagos/patologia , Masculino , Metaloproteinases da Matriz/metabolismo , Camundongos , Modelos Biológicos , Inibidor 1 de Ativador de Plasminogênio/genética , Ratos , Ratos Sprague-Dawley , Inibidor Tecidual de Metaloproteinase-1/genética , Fator de Crescimento Transformador beta/genética
15.
J Biomed Opt ; 14(1): 014001, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19256689

RESUMO

The polarization dependence of second harmonic generation (SHG) microscopy is used to uncover structural information in different muscle cells in a living Caenorhabditis elegans (C. elegans) nematode. This is done by using a generalized biophysical model in which element ratios for the associated second-order nonlinear tensor and angular orientations for thick filaments are retrieved using a pixel-by-pixel fitting algorithm. As a result, multiple arbitrary orientations of thick filaments, at the pixel-resolution level, are revealed in the same image. The validity of our method is first corroborated in well-organized thick filaments such as the nonfibrilar body wall muscles. Next, a region of the nonstriated muscular cells of the pharynx is analyzed by showing different regions with homogenous orientations of thick filament as well as their radial distribution. As a result, different sets of the nonstriated muscle cell groups in the pharynx of this nematode were exposed. This methodology is presented as a filtering mechanism to uncover biological information unreachable by common intensity SHG microscopy. Finally, a method to experimentally retrieve the distribution of the effective orientation of active SHG molecules is proposed and tested.


Assuntos
Algoritmos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Microscopia de Polarização/métodos , Células Musculares/ultraestrutura , Sarcômeros/ultraestrutura , Animais , Caenorhabditis elegans/citologia , Microscopia Eletrônica de Varredura/métodos , Microscopia de Fluorescência por Excitação Multifotônica , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
Oecologia ; 136(4): 565-70, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12838401

RESUMO

In animal-pollinated flowers, the pollinators cannot detect the presence of nectar before entering flowers, and therefore flowers may cheat by not producing nectar. An earlier model suggested that a mixed strategy of producing nectarful and nectarless flowers would be evolutionarily stable. Here we compare nectarless flowers as a cheating strategy with three competing hypotheses namely "visit-more-flowers", "cross-pollination enhancement" and "better contact". We collected field data on 28 species of plants to test some of the differential predictions of the hypotheses. Nectarless flowers were detected in 24 out of 28 plant species. Correlations of percent nectarless flowers with floral and ecological variables support the cheater flower hypothesis. We further model the cost-benefits of cheating and show that an evolutionary stable ratio of nectarless to nectarful flowers can be reached. The equilibrium ratio is mainly decided by factors associated with pollinator density and pollinator learning.


Assuntos
Evolução Biológica , Flores , Modelos Teóricos , Plantas , Animais , Ecologia , Reprodução
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