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1.
Int Q Community Health Educ ; : 272684X211004737, 2021 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-33752546

RESUMO

INTRODUCTION: During the care of incapacitated patients, physicians, and medical residents discuss treatment options and gain consent to treat through healthcare surrogates. The purpose of this study is to ascertain medical residents' knowledge of healthcare consent laws, application during clinical practice, and appraise the education residents received regarding surrogate decision making laws. METHODS: Beginning in February of 2018, 35 of 113 medical residents working with patients within Indiana completed a survey. The survey explored medical residents' knowledge of health care surrogate consent laws utilized in Indiana hospitals and Veterans Affairs (VA) hospitals via clinical vignettes. RESULTS: Only 22.9% of medical residents knew the default state law in Indiana did not have a hierarchy for settling disputes among surrogates. Medical residents correctly identified which family members could participate in medical decisions 86% of the time. Under the Veterans Affairs surrogate law, medical residents correctly identified appropriate family members or friends 50% of the time and incorrectly acknowledged the chief decision makers during a dispute 30% of the time. All medical residents report only having little or some knowledge of surrogate decision making laws with only 43% having remembered receiving surrogate decision making training during their residency. CONCLUSIONS: These findings demonstrate that medical residents lack understanding of surrogate decision making laws. In order to ensure medical decisions are made by the appropriate surrogates and patient autonomy is upheld, an educational intervention is required to train medical residents about surrogate decision making laws and how they are used in clinical practice.

2.
Anesth Analg ; 121(5): 1231-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26332856

RESUMO

BACKGROUND: The use of an intraoperative lung-protective ventilation strategy through tidal volume (TV) size reduction and positive end-expiratory pressure (PEEP) has been increasingly investigated. In this article, we describe the current intraoperative lung-protective ventilation practice patterns and trends. METHODS: By using the Multicenter Perioperative Outcomes Group database, we identified all general endotracheal anesthetics from January 2008 through December 2013 at 10 institutions. The following data were calculated: (1) percentage of patients receiving TV > 10 mL/kg predicted body weight (PBW); (2) median initial and overall TV in mL/kg PBW and; (3) percentage of patients receiving PEEP ≥ 5 cm H2O. The data were analyzed at 3-month intervals. Interinstitutional variability was assessed. RESULTS: A total of 330,823 patients met our inclusion criteria for this study. During the study period, the percentage of patients receiving TV > 10 mL/kg PBW was reduced for all patients (26% to 14%) and in the subpopulations of obese (41% to 25%), short stature (52% to 36%), and females (39% to 24%; all P values <0.001). There was a significant reduction in TV size (8.90-8.20 mL/kg PBW, P < 0.001). There was also a statistically significant but clinically irrelevant difference between initial and overall TV size (8.65 vs 8.63 mL/kg PBW, P < 0.001). Use of PEEP ≥ 5 cm H2O increased during the study period (25%-45%, P < 0.001). TV usage showed significant interinstitutional variability (P < 0.001). CONCLUSIONS: Although decreasing, a significant percentage of patients are ventilated with TV > 10 mL/kg PBW, especially if they are female, obese, or of short stature. The use of PEEP ≥ 5 cm H2O has increased significantly. Creating awareness of contemporary practice patterns and demonstrating the efficacy of lung-protective ventilation are still needed to optimize intraoperative ventilation.


Assuntos
Cuidados Intraoperatórios/tendências , Pulmão/fisiologia , Respiração com Pressão Positiva/tendências , Relatório de Pesquisa/tendências , Volume de Ventilação Pulmonar/fisiologia , Feminino , Humanos , Cuidados Intraoperatórios/métodos , Masculino , Respiração com Pressão Positiva/métodos , Estudos Retrospectivos , Resultado do Tratamento
3.
J Dairy Sci ; 98(12): 8710-22, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26409968

RESUMO

Efficacy of 2 cooling systems (Korral Kool, KK, Korral Kool Inc., Mesa, AZ; FlipFan dairy system, FF, Schaefer Ventilation Equipment LLC, Sauk Rapids, MN) was estimated utilizing 400 multiparous Holstein dairy cows randomly assigned to 1 of 4 cooled California-style shade pens (2 shade pens per cooling system). Each shaded pen contained 100 cows (days in milk=58±39, milk production=56±18 kg/d, and lactation=3±1). Production data (milk yield and reproductive performance) were collected during 3mo (June-August, 2013) and physiological responses (core body temperature, respiration rates, surface temperatures, and resting time) were measured in June and July to estimate responses of cows to the 2 different cooling systems. Water and electricity consumption were recorded for each system. Cows in the KK system displayed slightly lower respiration rates in the month of June and lower surface temperatures in June and July. However, no differences were observed in the core body temperature of cows, resting time, feed intake, milk yield, services/cow, and conception rate between systems. The FF system used less water and electricity during this study. In conclusion, both cooling systems (KK and FF) were effective in mitigating the negative effects of heat stress on cows housed in arid environments, whereas the FF system consumed less water and electricity and did not require use of curtains on the shade structure.


Assuntos
Ar Condicionado/instrumentação , Bovinos/fisiologia , Indústria de Laticínios/instrumentação , Abrigo para Animais , Animais , Temperatura Corporal , Doenças dos Bovinos/prevenção & controle , Indústria de Laticínios/métodos , Meio Ambiente , Feminino , Transtornos de Estresse por Calor/prevenção & controle , Transtornos de Estresse por Calor/veterinária , Lactação/fisiologia , Leite/química , Reprodução/fisiologia , Taxa Respiratória , Arábia Saudita , Estações do Ano , Temperatura
4.
Behav Neurosci ; 123(3): 577-88, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19485564

RESUMO

We previously demonstrated that lesions of the nucleus accumbens (NAc) core enhanced locomotion and locomotor sensitization to repeated injections of nicotine in rats (Kelsey & Willmore, 2006). In this study, we compared the effects of separate lesions of the NAc core, NAc medial shell, and basolateral amygdala on context-specific locomotor sensitization to repeated injections of 0.4 mg/kg nicotine. Electrolytic lesions of the NAc core increased locomotion, and lesions of the core (but not the shell) and the basolateral amygdala enhanced context-specific locomotor sensitization by enhancing the development of sensitization in paired rats and decreasing expression in unpaired rats relative to sham-operated rats when challenged with an injection of 0.4 mg/kg nicotine in the locomotor chambers. These data are consistent with findings that the NAc core and the basolateral amygdala share a variety of behavioral functions and anatomical connections. The findings that lesions of these structures enhance context-specific locomotor sensitization while typically impairing other reward-related behaviors also indicate that the processes underlying locomotor sensitization and reward are not identical.


Assuntos
Tonsila do Cerebelo/fisiologia , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Núcleo Accumbens/fisiologia , Análise de Variância , Animais , Eletrólise , Masculino , Distribuição Aleatória , Ratos , Ratos Long-Evans
5.
Curr Med Res Opin ; 24(4): 1101-14, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18328120

RESUMO

OBJECTIVES: The objective of this study was to evaluate the effects of losartan +/- hydrochlorothiazide (HCTZ) versus placebo in obese patients with systolic and diastolic hypertension. RESEARCH DESIGN AND METHODS: Randomized patients (n = 261) were non-diabetic with systolic blood pressure (SBP) > or = 140 and < or = 180 mmHg and diastolic BP (DBP) > or = 95 and < or = 115 mmHg, body mass index > 30 kg/m(2), and waist circumference > 40 (males)/> 35 (females) inches. Patients were randomized to placebo or a forced titration of losartan 50 mg titrated at 4-week intervals to losartan 100 mg, losartan 100 mg/HCTZ 12.5 mg, and losartan 100 mg/HCTZ 25 mg. Primary efficacy measurements were change from baseline in SBP and DBP at 12 weeks. Secondary measurements were change from baseline in BPs at 8 and 16 weeks, percent responders at 12 and 16 weeks, and safety/tolerability. Post-hoc analyses were BP at 4 weeks and achievement of controlled BP (SBP < 140 and/or DBP < 90 mmHg) at 12 and 16 weeks. RESULTS: Losartan 50 mg reduced BP from 151.6/99.2 mmHg at baseline to 140.1/89.8 mmHg at week 4 (post hoc), 139.5/89.6 mmHg with losartan 100 mg at week 8 (secondary), 134.3/85.9 mmHg with losartan 100 mg/HCTZ 12.5 mg at week 12 (primary), and 132.1/84.9 mmHg with losartan 100 mg/HCTZ 50 mg at week 16 (secondary) (all p < 0.05). Rates of clinical adverse experiences were similar between treatment groups. A limitation of these analyses is the relatively rapid rate of study drug titration, which may not have allowed for the evaluation of the full treatment effect at each titration step. CONCLUSIONS: We conclude that losartan alone or in combination with HCTZ was generally well tolerated and effective in the treatment of elevated systolic and diastolic BP in obese patients with hypertension.


Assuntos
Anti-Hipertensivos/uso terapêutico , Hidroclorotiazida/uso terapêutico , Hipertensão/tratamento farmacológico , Losartan/uso terapêutico , Obesidade/fisiopatologia , Adulto , Idoso , Anti-Hipertensivos/efeitos adversos , Pressão Sanguínea/efeitos dos fármacos , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Hidroclorotiazida/efeitos adversos , Hipertensão/complicações , Hipertensão/fisiopatologia , Losartan/efeitos adversos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Fatores de Tempo , Resultado do Tratamento
6.
Kidney Int ; 73(5): 630-6, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18094675

RESUMO

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers can decrease hemoglobin, causing anemia and this may be an independent risk factor for chronic kidney disease progression. We studied the relationship between a decline in hemoglobin and outcome in 1513 patients with type 2 diabetes and kidney disease by a post hoc analysis of the RENAAL Study (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) with an average follow-up of 3.4 years. The relationship between baseline and year-1 hemoglobin and treatment on end-stage renal disease (ESRD) and ESRD or death was evaluated using multivariate Cox models (covariates: baseline hemoglobin, proteinuria, serum albumin, serum creatinine, and year-1 hemoglobin). Compared with placebo, losartan treatment was associated with a significant decrease of hemoglobin, with the largest between-group difference at 1 year. After adjustment, there were significant relative risk reductions for losartan compared with placebo for ESRD and for ESRD or death regardless of the baseline hemoglobin even in those patients with a baseline hemoglobin below 120 g l(-1). Hence, the renoprotective properties of losartan were maintained despite a significant lowering of the hemoglobin concentration.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Diabetes Mellitus Tipo 2/complicações , Nefropatias Diabéticas/tratamento farmacológico , Hemoglobinas/efeitos dos fármacos , Losartan/uso terapêutico , Idoso , Anemia/etiologia , Anemia/prevenção & controle , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Método Duplo-Cego , Feminino , Hemoglobinas/análise , Humanos , Falência Renal Crônica/etiologia , Falência Renal Crônica/mortalidade , Falência Renal Crônica/prevenção & controle , Losartan/farmacologia , Masculino , Pessoa de Meia-Idade , Placebos , Estudos Prospectivos , Resultado do Tratamento
7.
J Intern Med ; 262(4): 439-48, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17875180

RESUMO

OBJECTIVES: Physical activity (PA) is a preventive strategy for cardiovascular disease and for managing cardiovascular risk factors. There is little information on the effectiveness of PA for the prevention of cardiovascular outcomes once cardiovascular disease is present. Thus, we studied the relationship between PA at baseline and cardiovascular events in a high-risk population. DESIGN: A prespecified analyses of observational data in a prospective, randomized hypertension study. SETTING: Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. SUBJECTS: Hypertension and left ventricular hypertrophy (LVH) (n = 9,193). INTERVENTIONS: Losartan versus atenolol. MAIN OUTCOME MEASURES: Reported level of PA: never exercise, exercise 30 min twice per week at baseline and after a mean of 4.8 years of treatment with losartan- versus atenolol-based therapy. Risk reductions were calculated by level of PA for the primary composite end-point and its components cardiovascular death, stroke and myocardial infarction, and also all-cause mortality and new-onset diabetes. RESULTS: A modest level of PA (>30 min twice per week) was associated with significant reductions in risk for the primary composite end-point [adjusted hazard ratio (aHR) 0.70, P < 0.001) and its components, all-cause mortality (aHR 0.65, P < 0.001), and new-onset diabetes (aHR 0.66, P < 0.001). CONCLUSION: A modest level of self-reported PA (>30 min twice per week) in patients with hypertension and LVH in the LIFE study was associated with significant reductions in risk for the primary composite end-point and its components of cardiovascular death, stroke, and myocardial infarction, all-cause mortality, and new-onset diabetes.


Assuntos
Anti-Hipertensivos/uso terapêutico , Atenolol/uso terapêutico , Doenças Cardiovasculares/prevenção & controle , Hipertensão/tratamento farmacológico , Losartan/uso terapêutico , Atividade Motora/fisiologia , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/tratamento farmacológico , Complicações do Diabetes/prevenção & controle , Métodos Epidemiológicos , Feminino , Humanos , Hipertensão/terapia , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Hipertrofia Ventricular Esquerda/prevenção & controle , Hipertrofia Ventricular Esquerda/terapia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/prevenção & controle , Resultado do Tratamento
8.
J Hum Hypertens ; 21(8): 625-32, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17476291

RESUMO

The relation of metabolic syndrome (MetS) with cardiovascular outcome may be less evident when preclinical cardiovascular disease is present. We explored, in a post hoc analysis, whether MetS predicts cardiovascular events in hypertensive patients with electrocardiographic left ventricular hypertrophy (ECG-LVH) in the Losartan Intervention For Endpoint (LIFE) reduction in hypertension study. MetS was defined by >or=2 risk factors plus hypertension: body mass index >or=30 kg/m(2), high-density lipoprotein (HDL)-cholesterol <1.0/1.3 mmol/l (<40/50 mg/dl) (men/women), glucose >or=6.1 mmol/l (>or=110 mg/dl) fasting or >or=7.8 mmol/l (>or=140 mg/dl) nonfasting or diabetes. Cardiovascular death and the primary composite end point (CEP) of cardiovascular death, stroke and myocardial infarction were examined. In MetS (1,591 (19.3%) of 8,243 eligible patients), low HDL-cholesterol (72%), obesity (77%) and impaired glucose (73%) were similarly prevalent, with higher blood pressure, serum creatinine and Cornell product, but lower Sokolow-Lyon voltage (all P<0.001). After adjusting for baseline covariates, hazard ratios for CEPs and cardiovascular death (4.8+/-1.1 years follow-up) were 1.47 (95% confidence interval (CI), 1.27-1.71)- and 1.73 (95% CI, 1.38-2.17)-fold higher with MetS (both P<0.0001), and were only marginally reduced when further adjusted for diabetes, obesity, low HDL-cholesterol, non-HDL-cholesterol, pulse pressure and in-treatment systolic blood pressure and heart rate. Thus, MetS is associated with increased cardiovascular events in hypertensive patients with ECG-LVH, independently of single cardiovascular risk factors.


Assuntos
Doenças Cardiovasculares/etiologia , Hipertensão/complicações , Hipertrofia Ventricular Esquerda/complicações , Losartan/uso terapêutico , Síndrome Metabólica/complicações , Idoso , Doenças Cardiovasculares/mortalidade , Eletrocardiografia , Feminino , Humanos , Hipertensão/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Fatores de Risco , Triglicerídeos/sangue
9.
Ann N Y Acad Sci ; 1071: 538-41, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16891614

RESUMO

Male Sprague-Dawley rats were trained and tested in the fear-potentiated startle (FPS) paradigm to examine the involvement of the bed nucleus of the stria terminalis (BST) in the expression of conditioned fear. Studies were designed to (a) detect physiological changes in the BST that might correlate with different levels of FPS expression and (b) determine if chemical inactivation of the BST with muscimol (1 ng) had any effect on FPS expression. The data suggest that the BST plays a role in the expression of conditioned fear and that GABA-mediated inhibition at this level may influence the level of this expression.


Assuntos
Condicionamento Clássico/fisiologia , Medo/fisiologia , Núcleos Septais/fisiologia , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Masculino , Estimulação Luminosa , Ratos , Ratos Sprague-Dawley , Reflexo de Sobressalto/fisiologia
10.
J Neurosci ; 26(14): 3855-63, 2006 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-16597740

RESUMO

The neuropeptide corticotropin-releasing factor (CRF) is believed to play a role in a number of psychiatric conditions, including anxiety disorders and depression. In the present study, male Sprague Dawley rats were used to examine the behavioral effects of altering dopamine transmission on CRF-enhanced startle, a behavioral assay believed to reflect stress- or anxiety-like states. Systemic administration of the selective dopamine D1 receptor antagonist SCH 23390 [R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride] (0, 0.01, 0.05, 0.1, 0.5 mg/kg) dose dependently blocked the effect of CRF (1 microg, i.c.v.) on startle at doses that had no effect on baseline startle response. Immunohistochemical studies showed that most CRF-containing cells in the dorsolateral division of the bed nucleus of the stria terminalis (BSTld), part of the critical brain area mediating CRF-enhanced startle, are surrounded by a dense plexus of tyrosine hydroxylase (TH)-positive fibers. Intra-BSTld injections of the retrograde tracer Fluorogold (FG) into the TH field identified neurons in the major dopaminergic areas (A8-A10), but not the major noradrenergic areas [A5, A6 (locus ceruleus), A7], as a significant source of TH-positive innervation. The majority of FG-filled cells double-labeled for TH were found in the dorsocaudal A10 cell group (A10dc) located in the periaqueductal gray area. Together, these data suggest that neuronal regulation of the BSTld by specific dopaminergic pathways and receptors may be an important mechanism for controlling CRF-dependent moods and affective states. These data also suggest that compounds with D1 receptor antagonist properties might have anxiolytic-like effects that could be useful for treating conditions associated with hyperactive CRF systems.


Assuntos
Encéfalo/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Dopamina/metabolismo , Reflexo de Sobressalto/fisiologia , Animais , Comportamento Animal/fisiologia , Masculino , Neurotransmissores/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/fisiologia
12.
Eur J Neurosci ; 23(1): 239-50, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16420433

RESUMO

The amygdala plays key roles in several aspects of addiction to drugs of abuse. This brain structure has been implicated in behaviours that reflect drug reward, drug seeking, and the aversive effects of drug withdrawal. Using a model that involves repeated cocaine injections to approximate 'binge' intoxication, we show in rats that during cocaine withdrawal, the impact of rewarding brain stimulation is attenuated, as quantified by alterations in intracranial self-stimulation (ICSS) behaviour. These behavioural signs of withdrawal are accompanied by enhancements of glutamatergic synaptic transmission within the lateral amygdala (LA) that occlude electrically induced long-term potentiation (LTP) in tissue slices. Synaptic enhancements during periods of cocaine withdrawal are mechanistically similar to LTP induced with electrical stimulation in control slices, as both forms of synaptic plasticity involve an increase in glutamate release. These results suggest that mechanisms of LTP within the amygdala are recruited during withdrawal from repeated exposure to cocaine. As such, they raise the possibility that the development and maintenance of addictive behaviours may involve, at least in part, mechanisms of synaptic plasticity within specific amygdala circuits.


Assuntos
Tonsila do Cerebelo/fisiologia , Cocaína/administração & dosagem , Inibidores da Captação de Dopamina/administração & dosagem , Potenciação de Longa Duração/efeitos dos fármacos , Síndrome de Abstinência a Substâncias/fisiopatologia , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Animais , Comportamento Animal , Relação Dose-Resposta à Radiação , Estimulação Elétrica/métodos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Potenciais Pós-Sinápticos Excitadores/efeitos da radiação , Medo , Agonistas GABAérgicos/farmacologia , Potenciação de Longa Duração/fisiologia , Potenciação de Longa Duração/efeitos da radiação , Masculino , Muscimol/farmacologia , Ratos , Ratos Sprague-Dawley , Reflexo de Sobressalto/efeitos dos fármacos , Reflexo de Sobressalto/fisiologia , Reflexo de Sobressalto/efeitos da radiação , Autoadministração , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia , Transmissão Sináptica/efeitos da radiação , Fatores de Tempo
17.
Am Heart J ; 128(3): 551-6, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8074019

RESUMO

Significant decreases in blood pressure (BP) may occur when administration of angiotensin-converting enzyme (ACE) inhibitors is initiated for the treatment of heart failure. The purpose of this study was to compare the safety and tolerability of recommended initial doses of the longer-acting ACE inhibitor enalapril (ENAL) with those of the shorter-acting captopril (CAP) in patients with heart failure who were treated concomitantly with digitalis and diuretic agents. We evaluated BP, serum ACE activity, and clinical status when a low, first dose of ENAL (2.5 mg, n = 59) or CAP (6.25 mg, n = 58) was administered in a double-blind, randomized, and parallel fashion to 117 patients with mild to moderate heart failure. BP and serum ACE activity were measured at 30 min and hourly for 8 hours after drug administration. BP decreases were similar for both groups (mean supine BP -6.2/-4.8 mm Hg for ENAL vs -8.3/-6.4 mm Hg for CAP; mean standing BP -9.2/-5.6 mm Hg for ENAL vs -10.0/-4.7 mm Hg for CAP). Although the maximum mean decrease in BP occurred at hours 4 and 5 in the ENAL group and hours 1 and 2 in the CAP group, considerable between-group overlap was observed for individual patients. Decreases in mean serum ACE activity occurred earlier and were of shorter duration in the CAP group. ENAL significantly inhibited serum ACE activity to a greater extent than did CAP at all time points except the 1st hour. Administration of a first dose of ENAL, 2.5 mg or CAP, 6.25 mg to patients with heart failure was well tolerated.


Assuntos
Captopril/administração & dosagem , Enalapril/administração & dosagem , Insuficiência Cardíaca/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea/efeitos dos fármacos , Captopril/efeitos adversos , Método Duplo-Cego , Tolerância a Medicamentos , Enalapril/efeitos adversos , Humanos , Pessoa de Meia-Idade , Peptidil Dipeptidase A/sangue , Segurança
18.
Photosynth Res ; 31(3): 167-94, 1992 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24408059

RESUMO

The underlying principles of spectral hole burning spectroscopies and the theory for hole profiles are reviewed and illustrated with calculated spectra. The methodology by which the dependence of the overall hole profile on burn wavelength can be used to reveal the contributions from site inhomogeneous broadening and various homogeneous broadening contributions to the broad Qy-absorption bands of cofactors is emphasized. Applications to the primary electron donor states of the reaction centers of purple bacteria and Photosystems I and II of green plants are discussed. The antenna (light harvesting) complexes considered include B800-B850 and B875 of Rhodobacter sphaeroides and the base-plate complex of Prosthecochloris aestuarii with particular attention being given to excitonic interactions and level structure. The data presented show that spectral hole burning is a generally applicable low temperature approach for the study of excited state electronic and vibrational (intramolecular, phonon) structures, structural heterogeneity and excited state lifetimes.

19.
J Med Chem ; 34(10): 3132-8, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1920362

RESUMO

Basic nitrobenzenesulfonamides containing nitroisopropyl and (ureidooxy)methyl groups were prepared and evaluated as novel hypoxic cell selective cytotoxic agents. In vitro, N-(2-aminoethyl)-N-methyl-3-nitro-4-(1-methyl-1-nitroethyl)benzene sulfonamide hydrochloride (11) proved to be preferentially toxic to hypoxic EMT6 mammary carcinoma cells. At 1 mM concentration in vitro, 11 reduced the surviving fraction of these hypoxic cells to 3 x 10(-3) with no effect on aerobic cells. In radiation experiments, 11 appeared to function as a hypoxic cell radiosensitizer as well as a selective cytotoxic agent. However, administration of 11 at 200 mg/kg ip or 100 mg/kg iv to BALB/c mice implanted with solid EMT6 tumors produced no evidence of significant in vivo cytotoxic or radiosensitizing activity. N-Methyl-N-[2-(methylamino)ethyl]-3-nitro-4- [(ureidooxy)methyl]benzenesulfonamide hydrochloride (20) showed slight differential toxicity toward EMT6 cells at 3 mM concentration and radiosensitizing activity comparable to misonidazole at 1 mM concentration.


Assuntos
Antineoplásicos/farmacologia , Nitrobenzenos/farmacologia , Oxigênio/administração & dosagem , Sulfonamidas/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/uso terapêutico , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Mamárias Experimentais/tratamento farmacológico , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Nitrobenzenos/síntese química , Nitrobenzenos/química , Nitrobenzenos/uso terapêutico , Sulfonamidas/síntese química , Sulfonamidas/química , Sulfonamidas/uso terapêutico , Células Tumorais Cultivadas
20.
J Med Chem ; 33(9): 2590-5, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2391697

RESUMO

Some 3'- and 5'-[[(alkylamino)ethyl]glycyl] esters of 5-bromo-2'-deoxyuridine were prepared and evaluated in vitro as progenitors of the parent alcohol. The esters proved to be relatively stable at low pH but released 5-bromo-2'-deoxyuridine cleanly at rates which were pH and structure dependent. These basic esters are examples of cyclization-activated prodrugs in which generation of active drug is not linked to enzymatic cleavage but rather results from an intramolecular cyclization-elimination reaction.


Assuntos
Bromodesoxiuridina/análogos & derivados , Pró-Fármacos/síntese química , Fenômenos Químicos , Química , Ciclização , Ésteres , Pró-Fármacos/farmacocinética , Relação Estrutura-Atividade
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