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1.
BMC Med Educ ; 23(1): 173, 2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36941597

RESUMO

BACKGROUND: In medicine, critical thinking is required for managing and tolerating medical uncertainty, as well as solving professional problems and treating diseases. However, the core of Confucianism, teacher-centered and exam-oriented settings in middle and high school education may pose challenges to developing critical thinking in Han Chinese or Taiwanese students. Students may be adversely affected by these pedagogies since student-centered settings were more effective in stimulating their critical and reflective thinking, as well as a sense of responsibility, in the ever-changing world. Therefore, guiding students with less stable foundations of critical thinking might require a different approach. A review article highlighted the potential utility of the Socratic method as a tool for teaching critical thinking in the healthcare field. The method involves posing a series of questions to students. More importantly, medical students and residents in clinical teaching are familiar with the method. Almost all healthcare students must complete a biochemistry laboratory course as part of their basic science training. Thus, we aimed to train students to develop critical thinking in the biochemistry laboratory course by using learning sheets and teacher guidance based on the Socratic method and questioning. METHOD: We recruited second-year students from a medical school, of whom 32 had medical science and biotechnology majors (MSB), 27 had pharmaceutical science majors (PS), and 85 were medical undergraduate (MU) students. An exercise in critical thinking was conducted during a biochemistry laboratory course, which consisted of five different biochemical experiments, along with learning sheets that contained three or four critical thinking questions. Then, the teacher evaluated the students' ability to think critically based on nine intellectual dimensions (clarity, accuracy, precision, relevance, depth, breadth, logic, fairness, and significance) based on the universal intellectual standards developed by Prof. Linda Elder and Richard Paul. In the following analysis, regression models and multivariate analysis were used to determine how students improved over time, and trajectory analysis were carried out in order to observe the trends in students' critical thinking skills construction. RESULTS: Clarity and logic dimensions were identified as the key elements to facilitate the development of critical thinking skills through learning sheets and teacher guidance in students across all three different healthcare majors. The results showed that metacognitive monitoring via Socratic questioning learning sheets have demonstrated potential encourage students to develop critical thinking skills in all dimensions. Another unique contribution of current study was present the heterogeneous learning patterns and progress trajectories of clarity and logic dimensions within classes. CONCLUSION: Using the Socratic learning model could effectively develop students' critical thinking skills so they can more effectively care for their patients.


Assuntos
Bacharelado em Enfermagem , Estudantes de Medicina , Humanos , Idoso , Pensamento , Resolução de Problemas , Bacharelado em Enfermagem/métodos , Atenção à Saúde
2.
PLoS Comput Biol ; 11(3): e1004153, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25826798

RESUMO

Target identification is one of the most critical steps following cell-based phenotypic chemical screens aimed at identifying compounds with potential uses in cell biology and for developing novel disease therapies. Current in silico target identification methods, including chemical similarity database searches, are limited to single or sequential ligand analysis that have limited capabilities for accurate deconvolution of a large number of compounds with diverse chemical structures. Here, we present CSNAP (Chemical Similarity Network Analysis Pulldown), a new computational target identification method that utilizes chemical similarity networks for large-scale chemotype (consensus chemical pattern) recognition and drug target profiling. Our benchmark study showed that CSNAP can achieve an overall higher accuracy (>80%) of target prediction with respect to representative chemotypes in large (>200) compound sets, in comparison to the SEA approach (60-70%). Additionally, CSNAP is capable of integrating with biological knowledge-based databases (Uniprot, GO) and high-throughput biology platforms (proteomic, genetic, etc) for system-wise drug target validation. To demonstrate the utility of the CSNAP approach, we combined CSNAP's target prediction with experimental ligand evaluation to identify the major mitotic targets of hit compounds from a cell-based chemical screen and we highlight novel compounds targeting microtubules, an important cancer therapeutic target. The CSNAP method is freely available and can be accessed from the CSNAP web server (http://services.mbi.ucla.edu/CSNAP/).


Assuntos
Biologia Computacional/métodos , Ensaios de Triagem em Larga Escala/métodos , Algoritmos , Sítios de Ligação , Bases de Dados Factuais , Desenho de Fármacos , Humanos , Ligantes
3.
Chem Res Toxicol ; 28(1): 43-50, 2015 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-25486454

RESUMO

Acrylamide (AA), a rodent carcinogen, is widely used in industry and present in cigarette smoke as well as in foods processed at high temperatures. The metabolic activation of AA to glycidamide (GA) could be critical for AA carcinogenicity since GA causes DNA adduct formation in vivo. N7-(2-carbamoyl-2-hydroxyethyl) guanine (N7-GAG), the most abundant DNA adduct of AA, is subjected to spontaneous and enzymatic depurination and excreted through urine. Urinary N7-GAG analysis can confirm AA genotoxicity and identify active species of AA metabolites in humans, thereby serving as a risk-associated biomarker for molecular epidemiology studies. This study aimed to develop an isotope-dilution solid-phase extraction liquid chromatography tandem mass spectrometry method to comparatively analyze urinary N7-GAG levels in nonsmokers and smokers. Urinary N-acetyl-S-(propionamide)-cysteine (AAMA), a metabolite of AA, was also analyzed as a biomarker for current AA exposure. Urinary N7-GAG was quantified by monitoring m/z 239 → 152 for N7-GAG and m/z 242 → 152 for (13)C3-labeled N7-GAG under positive electron spray ionization and multiple reaction mode. The median urinary N7-GAG level was 0.93 µg/g creatinine in nonsmokers (n = 33) and 1.41 µg/g creatinine in smokers (n = 30). Multiple linear regression analysis of data revealed that N7-GAG levels were only significantly associated with AAMA levels. These results demonstrate that urinary N7-GAG of nonsmokers and smokers is significantly associated with a very low level of dietary AA intake, assessed by analyzing urinary AAMA.


Assuntos
Acetilcisteína/análogos & derivados , Acrilamida/metabolismo , Carcinógenos/metabolismo , Cotinina/urina , Guanina/análogos & derivados , Fumar/urina , Acetilcisteína/urina , Adulto , Biomarcadores/urina , Dieta , Exposição Ambiental/análise , Guanina/urina , Humanos , Adulto Jovem
4.
ScientificWorldJournal ; 2015: 697569, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26171419

RESUMO

This study proposes virtual-reality (VR) simulator system for double interventional cardiac catheterization (ICC) using fractional-order vascular access tracker and haptic force producer. An endoscope or a catheter for diagnosis and surgery of cardiovascular disease has been commonly used in minimally invasive surgery. It needs specific skills and experiences for young surgeons or postgraduate year (PGY) students to operate a Berman catheter and a pigtail catheter in the inside of the human body and requires avoiding damaging vessels. To improve the training in inserting catheters, a double-catheter mechanism is designed for the ICC procedures. A fractional-order vascular access tracker is used to trace the senior surgeons' consoled trajectories and transmit the frictional feedback and visual feedback during the insertion of catheters. Based on the clinical feeling through the aortic arch, vein into the ventricle, or tortuous blood vessels, haptic force producer is used to mock the elasticity of the vessel wall using voice coil motors (VCMs). The VR establishment with surgeons' consoled vessel trajectories and hand feeling is achieved, and the experimental results show the effectiveness for the double ICC procedures.


Assuntos
Cateterismo Cardíaco , Cateteres Cardíacos , Simulação por Computador , Interface Usuário-Computador , Algoritmos , Angiografia , Cateterismo Cardíaco/instrumentação , Cateterismo Cardíaco/métodos , Doenças Cardiovasculares/diagnóstico por imagem , Doenças Cardiovasculares/cirurgia , Humanos , Processamento de Imagem Assistida por Computador , Procedimentos Cirúrgicos Minimamente Invasivos , Reprodutibilidade dos Testes
5.
Clin Nephrol ; 81(5): 359-62, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-23110773

RESUMO

A 68-year-old man presented with a spontaneous bilateral perirenal hemorrhage following a 2-month fever of unknown origin. A renal biopsy for a pathologic diagnosis seemed very risky because of the patient's bilateral perirenal hemorrhage. Therefore, we diagnosed polyarteritis nodosa using an abdominal computed tomography scan, a renal angiogram, and American College of Rheumatology criteria. The patient's multiple symptoms then responded well to the prescribed immunosuppressive regimen. This case is an uncommon presentation of polyarteritis nodosa with fever of unknown origin before a spontaneous bilateral perirenal hemorrhage.


Assuntos
Febre de Causa Desconhecida/complicações , Hemorragia/etiologia , Poliarterite Nodosa/complicações , Idoso , Anticorpos Anticitoplasma de Neutrófilos/análise , Humanos , Masculino , Tomografia Computadorizada por Raios X
6.
ScientificWorldJournal ; 2014: 203148, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24892039

RESUMO

This study proposes multiple-site hemodynamic analysis of Doppler ultrasound with an adaptive color relation classifier for arteriovenous access occlusion evaluation in routine examinations. The hemodynamic analysis is used to express the properties of blood flow through a vital access or a tube, using dimensionless numbers. An acoustic measurement is carried out to detect the peak-systolic and peak-diastolic velocities of blood flow from the arterial anastomosis sites (A) to the venous anastomosis sites (V). The ratio of the supracritical Reynolds (Re(supra)) number and the resistive (Res) index quantitates the degrees of stenosis (DOS) at multiple measurement sites. Then, an adaptive color relation classifier is designed as a nonlinear estimate model to survey the occlusion level in monthly examinations. For 30 long-term follow-up patients, the experimental results show the proposed screening model efficiently evaluates access occlusion.


Assuntos
Derivação Arteriovenosa Cirúrgica , Hemodinâmica , Ultrassonografia Doppler em Cores , Humanos , Diálise Renal
7.
Int J Cancer ; 132(6): 1475-85, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22915089

RESUMO

We investigated the in vitro metabolism and estrogenic and antiestrogenic activity of toremifene (TOR), tamoxifen (TAM) and their metabolites to better understand the potential effects of cytochrome P-450 2D6 (CYP2D6) status on the activity of these drugs in women with breast cancer. The plasma concentrations of TOR and its N-desmethyl (NDM) and 4-hydroxy (4-OH) metabolites during steady-state dosing with TOR were also determined. Unlike TOR, TAM and its NDM metabolite were extensively oxidized to 4-OH TAM and 4-OH-NDM TAM by CYP2D6, and the rate of metabolism was affected by CYP2D6 status. 4-OH-NDM TOR concentrations were not measurable at steady state in plasma of subjects taking 80 mg of TOR. Molecular modeling provided insight into the lack of 4-hydroxylation of TOR by CYP2D6. The 4-OH and 4-OH-NDM metabolites of TOR and TAM bound to estrogen receptor (ER) subtypes with fourfold to 30-fold greater affinity were 35- to 187-fold more efficient at antagonizing ER transactivation and had antiestrogenic potency that was up to 360-fold greater than their parent drugs. Our findings suggest that variations in CYP2D6 metabolic capacity may cause significant differences in plasma concentrations of active TAM metabolites (i.e., 4-OH TAM and 4-OH-NDM TAM) and contribute to variable pharmacologic activity. Unlike TAM, the clinical benefits in subjects taking TOR to treat metastatic breast cancer would not likely be subject to allelic variation in CYP2D6 status or affected by coadministration of CYP2D6-inhibiting medications.


Assuntos
Citocromo P-450 CYP2D6/fisiologia , Moduladores Seletivos de Receptor Estrogênico/metabolismo , Tamoxifeno/metabolismo , Toremifeno/metabolismo , Adulto , Humanos , Masculino , Oxirredução , Relação Estrutura-Atividade , Tamoxifeno/análogos & derivados , Tamoxifeno/sangue
8.
Med Microbiol Immunol ; 202(2): 105-15, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22797522

RESUMO

Group B streptococcus (GBS) is a common asymptomatic colonizer in acidic vagina of pregnant women and can transmit to newborns, causing neonatal pneumonia and meningitis. Biofilm formation is often associated with bacterial colonization and pathogenesis. Little is known about GBS biofilm and the effect of environmental stimuli on their growth along with biofilm formation. The objective of this study was to investigate the survival and biofilm formation of GBS, isolated from pregnant women, in nutrient-limited medium under various pH conditions. Growth and survival experiments were determined by optical density and viable counts. Crystal violet staining, scanning electron microscopy, and atomic force microscopy (AFM) were used to analyze the capacity of biofilm production. Our results showed that GBS isolates proliferated with increasing pH with highest maximum specific growth rate (µmax) at pH 6.5, but survived at pH 4.5 for longer than 48 h. Biofilm formation of the 80 GBS isolates at pH 4.5 was significantly higher than at pH 7.0. This difference was confirmed by two other methods. The low elastic modulus obtained from samples at pH 4.5 by AFM revealed the softness of biofilm; in contrast, little or no biofilm was measured at pH 7.0. Under acidic pH, the capability of biofilm formation of serotypes III and V showed statistically significant difference from serotypes Ia and Ib. Our finding suggested that survival and enhanced biofilm formation at vaginal pH are potentially advantageous for GBS in colonizing vagina and increase the risk of vaginosis and neonatal infection.


Assuntos
Biofilmes , Streptococcus agalactiae/fisiologia , Vagina/microbiologia , Adulto , Feminino , Perfilação da Expressão Gênica , Humanos , Concentração de Íons de Hidrogênio , Gravidez , Estudos Prospectivos , Sorotipagem , Streptococcus agalactiae/isolamento & purificação , Streptococcus agalactiae/ultraestrutura
9.
Pharm Res ; 29(11): 3040-52, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22410804

RESUMO

PURPOSE: To evaluate abilities of 2-aryl-4-benzoyl-imidazoles (ABI) to overcome multidrug resistance (MDR), define their cellular target, and assess in vivo antimelanoma efficacy. METHODS: MDR cell lines that overexpressed P-glycoprotein, MDR-associated proteins, and breast cancer resistance protein were used to evaluate ABI ability to overcome MDR. Cell cycle analysis, molecular modeling, and microtubule imaging were used to define ABI cellular target. SHO mice bearing A375 human melanoma xenograft were used to evaluate ABI in vivo antitumor activity. B16-F10/C57BL mouse melanoma lung metastasis model was used to test ABI efficacy to inhibit tumor lung metastasis. RESULTS: ABIs showed similar potency to MDR cells compared to matching parent cells. ABIs were identified to target tubulin on the colchicine binding site. After 31 days of treatment, ABI-288 dosed at 25 mg/kg inhibited melanoma tumor growth by 69%; dacarbazine at 60 mg/kg inhibited growth by 52%. ABI-274 dosed at 25 mg/kg showed better lung metastasis inhibition than dacarbazine at 60 mg/kg. CONCLUSIONS: This new class of antimitotic compounds can overcome several clinically important drug resistant mechanisms in vitro and are effective in inhibiting melanoma lung metastasis in vivo, supporting their further development.


Assuntos
Neoplasias Pulmonares/prevenção & controle , Melanoma/tratamento farmacológico , Melanoma/secundário , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Animais não Endogâmicos , Antimitóticos/farmacologia , Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Colchicina/metabolismo , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Feminino , Células HEK293 , Humanos , Imidazóis/farmacologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Melanoma/metabolismo , Melanoma/patologia , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Camundongos Pelados , Camundongos Endogâmicos C57BL , Camundongos SCID , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Metástase Neoplásica
10.
Pharm Res ; 29(11): 3053-63, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22760659

RESUMO

PURPOSE: To evaluate the efficacy and oral activity of two promising indoles, (2-(1H-indol-3-yl)-1H-imidazol-4-yl)(3,4,5-trimethoxyphenyl)methanone [compound II] and (2-(1H-indol-5-ylamino)-thiazol-4-yl)(3,4,5-trimethoxyphenyl)methanone [compound IAT], in paclitaxel- and docetaxel-resistant tumor models in vitro and in vivo. METHODS: The in vitro drug-like properties, including potency, solubility, metabolic stability, and drug-drug interactions were examined for our two active compounds. An in vivo pharmacokinetic study and antitumor efficacy study were also completed to compare their efficacy with docetaxel. RESULTS: Both compounds bound to the colchicine-binding site on tubulin, and inhibited tubulin polymerization, resulting in highly potent cytotoxic activity in vitro. While the potency of paclitaxel and docetaxel was compromised in a multidrug-resistant cell line that overexpresses P-glycoprotein, the potency of compounds II and IAT was maintained. Both compounds had favorable drug-like properties, and acceptable oral bioavailability (21-50 %) in mice, rats, and dogs. Tumor growth inhibition of greater than 100 % was achieved when immunodeficient mice with rapidly growing paclitaxel-resistant prostate cancer cells were treated orally at doses of 3-30 mg/kg of II or IAT. CONCLUSIONS: These studies highlight the potent and broad anticancer activity of two orally bioavailable compounds, offering significant pharmacologic advantage over existing drugs of this class for multidrug resistant or taxane-refractory cancers.


Assuntos
Indóis/farmacologia , Indóis/farmacocinética , Neoplasias/tratamento farmacológico , Paclitaxel/farmacologia , Moduladores de Tubulina/farmacologia , Moduladores de Tubulina/farmacocinética , Tubulina (Proteína)/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Sítios de Ligação/efeitos dos fármacos , Disponibilidade Biológica , Células CACO-2 , Linhagem Celular Tumoral , Colchicina/metabolismo , Docetaxel , Cães , Interações Medicamentosas , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Camundongos Nus , Neoplasias/metabolismo , Polimerização/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Taxoides/farmacologia
11.
Drug Metab Dispos ; 39(10): 1833-9, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21742898

RESUMO

Microtubules are critical components of the cytoskeleton. Perturbing their function arrests the growth of a broad spectrum of cancer cell lines, making microtubules an excellent and established target for chemotherapy. All of the U.S. Food and Drug Administration-approved antitubulin agents bind to paclitaxel or vinblastine binding sites in tubulin. Because of the complexity of their structures, it is difficult to structurally modify the vinca alkaloids and taxanes and develop orally bioavailable agents. Antitubulin agents that target the colchicine-binding site in tubulin may provide a better opportunity to be developed for oral use because of their relatively simple structures and physicochemical properties. A potent antitubulin agent, 4-(3,4,5-trimethoxybenzoyl)-2-phenyl-thiazole (SMART-H), binding to the colchicine-binding site, was discovered in our laboratory. However, the bioavailability of SMART-H was low because of its poor solubility. Structural modification of SMART-H led to the development of 2-aryl-4-benzoyl-imidazole analog (ABI-274), with improved bioavailability and potency but still considerable first-pass metabolism. A chlorine derivative (ABI-286), replacing the methyl site of ABI-274, resulted in 1.5-fold higher metabolic stability in vitro and 1.8-fold lower clearance in rats in vivo, indicating that metabolic stability of ABI-274 can be extended by blocking benzylic hydroxylation. Overall, ABI-274 and ABI-286 provided 2.4- and 5.5-fold increases in exposure (area under the curve) after oral dosing in rats compared with SMART-H. Most importantly, the structural modifications did not compromise potency. ABI-286 exhibited moderate clearance, moderate volume of distribution, and acceptable oral bioavailability. This study provided the first evidence that ABI-286 may be the first member of a new class of orally bioavailable antitubulin agents.


Assuntos
Colchicina/análogos & derivados , Colchicina/metabolismo , Imidazóis/farmacocinética , Tiazóis/farmacocinética , Administração Oral , Animais , Sítios de Ligação , Disponibilidade Biológica , Linhagem Celular Tumoral , Colchicina/química , Cães , Feminino , Humanos , Imidazóis/química , Masculino , Camundongos , Microssomos Hepáticos/metabolismo , Microtúbulos/metabolismo , Paclitaxel/farmacocinética , Ratos , Solubilidade , Relação Estrutura-Atividade , Tiazóis/química , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacocinética , Vimblastina/farmacocinética
12.
Drug Metab Dispos ; 39(4): 636-43, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21233217

RESUMO

3-(1H-Indol-2-yl)phenyl)(3,4,5-trimethoxyphenyl)methanone (I-387) is a novel indole compound with antitubulin action and potent antitumor activity in various preclinical models. I-387 avoids drug resistance mediated by P-glycoprotein and showed less neurotoxicity than vinca alkaloids during in vivo studies. We examined the pharmacokinetics and metabolism of I-387 in mice as a component of our preclinical development of this compound and continued interest in structure-activity relationships for antitubulin agents. After a 1 mg/kg intravenous dose, noncompartmental pharmacokinetic analysis in plasma showed that clearance (CL), volume of distribution at steady state (Vd(ss)), and terminal half-life (t(1/2)) of I-387 were 27 ml per min/kg, 5.3 l/kg, and 7 h, respectively. In the in vitro metabolic stability study, half-lives of I-387 were between 10 and 54 min by mouse, rat, dog, monkey, and human liver microsomes in the presence of NADPH, demonstrating interspecies variability. I-387 was most stable in rat liver microsomes and degraded quickly in monkey liver microsomes. Liquid chromatography-tandem mass spectrometry was used to identify phase I metabolites. Hydroxylation, reduction of a ketone group, and O-demethylation were the major metabolites formed by the liver microsomes of the five species. The carbonyl group of I-387 was reduced and identified as the most labile site in human liver microsomes. The results of these drug metabolism and pharmacokinetic studies provide the foundation for future structural modification of this pharmacophore to improve stability of drugs with potent anticancer effects in cancer patients.


Assuntos
Antimitóticos/metabolismo , Benzofenonas/metabolismo , Indóis/metabolismo , Microssomos Hepáticos/metabolismo , NADP/metabolismo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Antimitóticos/sangue , Antimitóticos/síntese química , Antimitóticos/farmacologia , Benzofenonas/sangue , Benzofenonas/síntese química , Benzofenonas/farmacologia , Biotransformação , Cães , Estabilidade de Medicamentos , Meia-Vida , Haplorrinos , Humanos , Hidroxilação , Indóis/sangue , Indóis/síntese química , Indóis/farmacologia , Injeções Intravenosas , Desintoxicação Metabólica Fase I , Desintoxicação Metabólica Fase II , Camundongos , Microssomos Hepáticos/efeitos dos fármacos , Ratos , Especificidade da Espécie , Relação Estrutura-Atividade
13.
Bioorg Med Chem ; 19(16): 4782-95, 2011 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-21775150

RESUMO

We previously reported the discovery of 2-aryl-4-benzoyl-imidazoles (ABI-I) as potent antiproliferative agents for melanoma. To further understand the structural requirements for the potency of ABI analogs, gain insight in the structure-activity relationships (SAR), and investigate metabolic stability for these compounds, we report extensive SAR studies on the ABI-I scaffold. Compared with the previous set of ABI-I analogs, the newly synthesized ABI-II analogs have lower potency in general, but some of the new analogs have comparable potency to the most active compounds in the previous set when tested in two melanoma and four prostate cancer cell lines. These SAR studies indicated that the antiproliferative activity was very sensitive to subtle changes in the ligand. Tested compounds 3ab and 8a are equally active against highly paclitaxel resistant cancer cell lines and their parental cell lines, indicating that drugs developed based on ABI-I analogs may have therapeutic advantages over paclitaxel in treating resistant tumors. Metabolic stability studies of compound 3ab revealed that N-methyl imidazole failed to extend stability as literature reported because de-methylation was found as the major metabolic pathway in rat and mouse liver microsomes. However, this sheds light on the possibility for many modifications on imidazole ring for further lead optimization since the modification on imidazole, such as compound 3ab, did not impact the potency.


Assuntos
Antineoplásicos/síntese química , Proliferação de Células/efeitos dos fármacos , Desenho de Fármacos , Imidazóis/síntese química , Terapia de Alvo Molecular , Moduladores de Tubulina/síntese química , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Encéfalo/efeitos dos fármacos , Linhagem Celular Tumoral , Cães , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Imidazóis/química , Masculino , Camundongos , Microssomos Hepáticos/efeitos dos fármacos , Modelos Moleculares , Polimerização , Ratos , Relação Estrutura-Atividade , Suínos , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/análise , Moduladores de Tubulina/farmacocinética , Moduladores de Tubulina/farmacologia
14.
Drug Metab Dispos ; 38(11): 2032-9, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20675405

RESUMO

Tubulins are some of the oldest and most extensively studied therapeutic targets for cancer. Although many tubulin polymerizing and depolymerizing agents are known, the search for improved agents continues. We screened a class of tubulins targeting small molecules and identified 4-(3,4,5-trimethoxybenzoyl)-2-phenyl-thiazole (SMART-H) as our lead compound. SMART-H inhibited the proliferation of a variety of cancer cells in vitro, at subnanomolar IC(50), and in vivo, in nude mice xenografts, with near 100% tumor growth inhibition. Metabolic stability studies with SMART-H in liver microsomes of four species (mouse, rat, dog, and human) revealed half-lives between <5 and 30 min, demonstrating an interspecies variability. The clearance predicted based on in vitro data correlated well with in vivo clearance obtained from mouse, rat, and dog in vivo pharmacokinetic studies. SMART-H underwent four major metabolic processes, including ketone reduction, demethylation, combination of ketone reduction and demethylation, and hydroxylation in human liver microsomes. Metabolite identification studies revealed that the ketone and the methoxy groups of SMART-H were most labile and that ketone reduction was the dominant metabolism reaction in human liver microsomes. We designed and tested four derivatives of SMART-H to improve the metabolic stability. The oxime and hydrazide derivatives, replacing the ketone site, demonstrated a 2- to 3-fold improved half-life in human liver microsomes, indicating that our prediction regarding metabolic stability of SMART-H can be extended by blocking ketone reduction. These studies led us to the next generation of SMART compounds with greater metabolic stability and higher pharmacologic potency.


Assuntos
Microssomos Hepáticos/metabolismo , Bibliotecas de Moléculas Pequenas/farmacocinética , Tiazóis/farmacocinética , Triazóis/farmacocinética , Moduladores de Tubulina/farmacocinética , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cães , Estabilidade de Medicamentos , Meia-Vida , Humanos , Masculino , Taxa de Depuração Metabólica , Camundongos , Camundongos Endogâmicos ICR , Valor Preditivo dos Testes , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Especificidade da Espécie , Tiazóis/síntese química , Tiazóis/química , Tiazóis/farmacologia , Triazóis/síntese química , Triazóis/química , Triazóis/farmacologia , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologia
15.
Pharmacol Res ; 61(2): 108-15, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19643180

RESUMO

DB-67 and its lactone homolog DB-91 are derivatives of topoisomerase I inhibitor camptothecin (CPT) with silyl moiety, which may exhibit a slower inactivation process by changed kinetics of protein binding and/or hydrolysis of its lactone ring and result in increased antitumor activity and decreased toxicity. Pharmacokinetic properties and antitumor activities of the two silatecans were studied and compared. The lactone ring of DB-91 is more stable than those of all the other CPT derivatives in mouse plasma. Both silatecans were metabolized faster than CPT in mouse and human liver microsomes. Pharmacokinetic study revealed a plasma elimination half-life (t(1/2)) of 33 and 94min for DB-67 and DB-91, respectively; similar systemic exposure in plasma between DB-67 and DB-91; and similar volume of distribution at the steady state between DB-67 and DB-91, approximately 15-fold smaller than that of CPT. While DB-91 showed limited activities, DB-67 exhibited activities against the growth of in vivo-like histocultured human tumors and s.c. xenografted human tumors in nude mice. In conclusion, DB-67 is more effective, compared to DB-91, against human tumor growth in in vitro, in vivo-like and in vivo systems. Further pre-clinical and clinical investigations of DB-67 are warranted.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Camptotecina/análogos & derivados , Inibidores Enzimáticos/farmacologia , Neoplasias/tratamento farmacológico , Compostos de Organossilício/farmacologia , Inibidores da Topoisomerase I , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/sangue , Antineoplásicos Fitogênicos/farmacocinética , Camptotecina/administração & dosagem , Camptotecina/sangue , Camptotecina/farmacocinética , Camptotecina/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Resistencia a Medicamentos Antineoplásicos , Estabilidade de Medicamentos , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacocinética , Feminino , Meia-Vida , Humanos , Injeções Intravenosas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Microssomos Hepáticos/metabolismo , Neoplasias/enzimologia , Neoplasias/patologia , Compostos de Organossilício/administração & dosagem , Compostos de Organossilício/sangue , Compostos de Organossilício/farmacocinética , Fatores de Tempo , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Bioorg Med Chem ; 18(2): 477-95, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20056548

RESUMO

A series of (2RS,4R)-2-arylthiazolidine-4-carboxylic acid amide (ATCAA) was synthesized. Antiproliferative activity against melanoma and prostate cancer cells compared with control cells (fibroblast and RH7777, respectively) was evaluated. Compound 3id showed the best selectivity and growth-inhibition activity against three melanoma cell lines (B16-F1, A375, and WM-164). Compounds 15b and 3ac had good selectivity and potency against four prostate cancer cell lines (DU 145, PC-3, LNCaP, and PPC-1). The structure-activity relationship (SAR) of the side chain, the thiazolidine ring, and phenyl substituents is discussed. Cell cycle analysis showed that the percentage of cancer cells undergoing apoptosis (sub-G1 phase) increased after treatment with 1b and 3ad, which also strongly inhibited melanoma colony formation. In vivo studies on nude mice bearing A375 melanoma tumors showed that compound 1b inhibited tumor growth in a dose-dependent manner. At a dose of 10mg/kg, 1b significantly inhibited melanoma tumor growth and showed higher efficacy than did dacarbazine at 60mg/kg.


Assuntos
Amidas/química , Amidas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Ácidos Carboxílicos/farmacologia , Tiazolidinas/química , Tiazolidinas/farmacologia , Amidas/síntese química , Animais , Antineoplásicos/química , Ácidos Carboxílicos/síntese química , Ácidos Carboxílicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Camundongos , Conformação Molecular , Estereoisomerismo , Relação Estrutura-Atividade , Tiazolidinas/síntese química , Células Tumorais Cultivadas
17.
Healthc Technol Lett ; 5(1): 38-44, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29515815

RESUMO

Blood leakage and blood loss are serious life-threatening complications occurring during dialysis therapy. These events have been of concerns to both healthcare givers and patients. More than 40% of adult blood volume can be lost in just a few minutes, resulting in morbidities and mortality. The authors intend to propose the design of a warning tool for the detection of blood leakage/blood loss during dialysis therapy based on fog computing with an array of photocell sensors and heteroassociative memory (HAM) model. Photocell sensors are arranged in an array on a flexible substrate to detect blood leakage via the resistance changes with illumination in the visible spectrum of 500-700 nm. The HAM model is implemented to design a virtual alarm unit using electricity changes in an embedded system. The proposed warning tool can indicate the risk level in both end-sensing units and remote monitor devices via a wireless network and fog/cloud computing. The animal experimental results (pig blood) will demonstrate the feasibility.

18.
J Appl Physiol (1985) ; 124(4): 899-905, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29357510

RESUMO

Acute respiratory distress syndrome (ARDS) is characterized by lung inflammation and pulmonary edema, leading to arterial hypoxemia and death if the hypoxemia is severe. Strategies to correct hypoxemia have the potential to improve clinical outcomes in ARDS. The goal of this study was to evaluate the potential of hemoglobin modification as a novel therapy for ARDS-induced hypoxemia. The therapeutic effect of two different doses of GBT1118, a compound that increases the oxygen affinity of hemoglobin, was evaluated in a murine model of acute lung injury induced by intratracheal LPS instillation 24 h before exposure to 5% or 10% hypoxia ( n = 8-15 per group). As expected, administration of GBT1118 to mice significantly increased the oxygen affinity of hemoglobin. Compared with mice receiving vehicle control, mice treated with GBT1118 had significantly lower mortality after LPS + 5% hypoxia (47% with vehicle vs. 22% with low-dose GBT1118, 13% with high-dose GBT1118, P = 0.032 by log rank) and had reduced severity of illness. Mice treated with GBT1118 showed a sustained significant increase in SpO2 over 4 h of hypoxia exposure. Treatment with GBT1118 did not alter alveolar-capillary permeability, bronchoalveolar lavage (BAL) inflammatory cell counts, or BAL concentrations of IL-1ß, TNF-α, or macrophage inflammatory protein-1α. High-dose GBT1118 did not affect histological lung injury but did decrease tissue hypoxia as measured intensity of pimonidazole (Hypoxyprobe) staining in liver ( P = 0.043) and kidney ( P = 0.043). We concluded that increasing the oxygen affinity of hemoglobin using GBT1118 may be a novel therapy for treating hypoxemia associated with acute lung injury. NEW & NOTEWORTHY In this study, we show that GBT1118, a compound that increases hemoglobin affinity for oxygen, improves survival and oxygen saturation in a two-hit lung injury model of intratracheal LPS without causing tissue hypoxia. Modulation of hemoglobin oxygen affinity represents a novel therapeutic approach to treatment of acute lung injury and acute respiratory distress syndrome, conditions characterized by hypoxemia.


Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Benzaldeídos/uso terapêutico , Niacinamida/análogos & derivados , Lesão Pulmonar Aguda/etiologia , Animais , Benzaldeídos/farmacologia , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Hipóxia/complicações , Hipóxia/tratamento farmacológico , Lipopolissacarídeos , Masculino , Camundongos Endogâmicos C57BL , Niacinamida/farmacologia , Niacinamida/uso terapêutico
19.
IET Syst Biol ; 11(2): 69-76, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28476975

RESUMO

Atherosclerosis and resultant peripheral arterial disease (PAD) are common complications in patients with type 2 diabetes mellitus or end-stage renal disease and in elderly patients. The prevalence of PAD is higher in patients receiving haemodialysis therapy. For early assessment of arterial occlusion using bilateral photoplethysmography (PPG), such as changes in pulse transit time and pulse shape, bilateral timing differences could be used to identify the risk level of PAD. Hence, the authors propose a discrete fractional-order integrator to calculate the bilateral area under the systolic peak (AUSP). These indices indicated the differences in both rise-timing and amplitudes of PPG signals. The dexter and sinister AUSP ratios were preliminarily used to separate the normal condition from low/high risk of PAD. Then, transition probability-based decision-making model was employed to evaluate the risk levels. The joint probability could be specified as a critical threshold, < 0.81, to identify the true positive for screening low or high risk level of PAD, referring to the patients' health records. In contrast to the bilateral timing differences and traditional methods, the proposed model showed better efficiency in PAD assessments and provided a promising strategy to be implemented in an embedded system.


Assuntos
Técnicas de Apoio para a Decisão , Técnicas de Diagnóstico Cardiovascular , Modelos Estatísticos , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/etiologia , Fotopletismografia , Diálise Renal/efeitos adversos , Algoritmos , Simulação por Computador , Tomada de Decisões Assistida por Computador , Técnicas de Diagnóstico Cardiovascular/instrumentação , Estudos de Viabilidade , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
IEEE Trans Biomed Circuits Syst ; 11(4): 784-793, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28727557

RESUMO

Blood leakage and blood loss are serious complications during hemodialysis. From the hemodialysis survey reports, these life-threatening events occur to attract nephrology nurses and patients themselves. When the venous needle and blood line are disconnected, it takes only a few minutes for an adult patient to lose over 40% of his / her blood, which is a sufficient amount of blood loss to cause the patient to die. Therefore, we propose integrating a flexible sensor and self-organizing algorithm to design a cloud computing-based warning device for blood leakage detection. The flexible sensor is fabricated via a screen-printing technique using metallic materials on a soft substrate in an array configuration. The self-organizing algorithm constructs a virtual direct current grid-based alarm unit in an embedded system. This warning device is employed to identify blood leakage levels via a wireless network and cloud computing. It has been validated experimentally, and the experimental results suggest specifications for its commercial designs. The proposed model can also be implemented in an embedded system.


Assuntos
Computação em Nuvem , Hemorragia/diagnóstico , Monitorização Fisiológica/instrumentação , Diálise Renal , Tecnologia sem Fio , Algoritmos , Sistemas Computacionais , Humanos
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