RESUMO
OBJECTIVE: To evaluate the current practice of preconception care in the Netherlands and the perceptions of birth care professionals concerning preconception care. METHODS: We have developed a digital questionnaire and conducted a cross-sectional study by distributing the questionnaire among 102 organisations: 90 primary care midwifery practices and obstetric departments of 12 hospitals in the Southwest region of the Netherlands between December 2020 and March 2021. One birth care professional per organization was asked to complete the questionnaire. Descriptive statistics were used to present the results. FINDINGS: Respondents of eighty-three organisations (81.4 %) filled in the questionnaire, of whom 74 respondents were independent primary care midwives and 9 respondents were obstetricians. Preconception care mostly consisted of an individual consultation in which personalized health and lifestyle advice was given. Among the respondents, 44.4 % reported that the organization had a preconception care protocol. The way in which the consultation was carried out, as well as the health and lifestyle related questions asked, differed between respondents. More than 85 % of the respondents inquire about the following possible risk factors for complications: maternal illnesses, obstetric history, folic acid supplement intake, alcohol intake, smoking, substance abuse, hereditary disease, prescription medication, dietary habits, overweight, and birth defects in the family. The respondents acknowledged that preconception care should be offered to all couples who wish to become pregnant, as opposed to offering preconception care only to those with an increased risk of complications. Still, respondents do not receive many questions regarding the preconception period or requests for preconception care consultations. KEY CONCLUSION: Birth care professionals acknowledge the need for preconception care for all couples. In the Netherlands, preconception care consists mostly of an individual consultation with recommendations for health and lifestyle advice. However, the identification of risk factors varies between birth care professionals and less than half of the respondents indicate that they have a protocol available in their practice. Furthermore, the demand of parents-to-be for preconception care is low. More research, that includes more obstetricians, is necessary to investigate if there is a difference between the care provided by primary care midwives and obstetricians. IMPLICATIONS FOR PRACTICE: To increase the awareness and uptake of preconception care, it would be prudent to emphasize its importance to parents-to-be and professionals, and actively promote the use of widespread, standardized protocols for birth care professionals.
Assuntos
Tocologia , Cuidado Pré-Concepcional , Gravidez , Feminino , Humanos , Cuidado Pré-Concepcional/métodos , Países Baixos , Estudos Transversais , Inquéritos e QuestionáriosRESUMO
UNLABELLED: We report the results of alendronate ingestion plus exercise in preventing the declines in bone mass and strength and elevated levels of urinary calcium and bone resorption in astronauts during 5.5 months of spaceflight. INTRODUCTION: This investigation was an international collaboration between NASA and the JAXA space agencies to investigate the potential value of antiresorptive agents to mitigate the well-established bone changes associated with long-duration spaceflight. METHODS: We report the results from seven International Space Station (ISS) astronauts who spent a mean of 5.5 months on the ISS and who took an oral dose of 70 mg of alendronate weekly starting 3 weeks before flight and continuing throughout the mission. All crewmembers had available for exercise a treadmill, cycle ergometer, and a resistance exercise device. Our assessment included densitometry of multiple bone regions using X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) and assays of biomarkers of bone metabolism. RESULTS: In addition to pre- and post-flight measurements, we compared our results to 18 astronauts who flew ISS missions and who exercised using an early model resistance exercise device, called the interim resistance exercise device, and to 11 ISS astronauts who exercised using the newer advanced resistance exercise device (ARED). Our findings indicate that the ARED provided significant attenuation of bone loss compared with the older device although post-flight decreases in the femur neck and hip remained. The combination of the ARED and bisphosphonate attenuated the expected decline in essentially all indices of altered bone physiology during spaceflight including: DXA-determined losses in bone mineral density of the spine, hip, and pelvis, QCT-determined compartmental losses in trabecular and cortical bone mass in the hip, calculated measures of fall and stance computed bone strength of the hip, elevated levels of bone resorption markers, and urinary excretion of calcium. CONCLUSIONS: The combination of exercise plus an antiresoptive drug may be useful for protecting bone health during long-duration spaceflight.
Assuntos
Alendronato/uso terapêutico , Conservadores da Densidade Óssea/uso terapêutico , Terapia por Exercício/métodos , Osteoporose/prevenção & controle , Voo Espacial , Absorciometria de Fóton/métodos , Adulto , Alendronato/administração & dosagem , Biomarcadores/sangue , Biomarcadores/urina , Composição Corporal/fisiologia , Densidade Óssea/efeitos dos fármacos , Densidade Óssea/fisiologia , Conservadores da Densidade Óssea/administração & dosagem , Reabsorção Óssea/etiologia , Reabsorção Óssea/prevenção & controle , Terapia Combinada , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/etiologia , Osteoporose/fisiopatologia , Ausência de Peso/efeitos adversosRESUMO
CONTEXT: Animal models and human studies suggest that osteocytes regulate the skeleton's response to mechanical unloading in part by an increase in sclerostin. However, few studies have reported changes in serum sclerostin in humans exposed to reduced mechanical loading. OBJECTIVE: We determined changes in serum sclerostin and bone turnover markers in healthy adult men undergoing controlled bed rest. DESIGN, SETTING, AND PARTICIPANTS: Seven healthy adult men (31 ± 3 yr old) underwent 90 d of 6° head down tilt bed rest at the University of Texas Medical Branch Institute for Translational Sciences-Clinical Research Center. OUTCOMES: Serum sclerostin, PTH, vitamin D, bone resorption and formation markers, urinary calcium and phosphorus excretion, and 24-h pooled urinary markers of bone resorption were evaluated before bed rest [baseline (BL)] and at bed rest d 28 (BR-28), d 60 (BR-60), and d 90 (BR-90). Bone mineral density was measured at BL, BR-60, and 5 d after the end of the study (BR+5). Data are reported as mean ± SD. RESULTS: Consistent with prior reports, bone mineral density declined significantly (1-2% per month) at weight-bearing skeletal sites. Serum sclerostin was elevated above BL at BR-28 (+29 ± 20%; P = 0.003) and BR-60 (+42 ± 31%; P < 0.001), with a lesser increase at BR-90 (+22 ± 21%; P = 0.07). Serum PTH levels were reduced at BR-28 (-17 ± 16%; P = 0.02) and BR-60 (-24 ± 14%; P = 0.03) and remained lower than BL at BR-90 (-21 ± 21%; P = 0.14), but did not reach statistical significance. Serum bone turnover markers were unchanged; however, urinary bone resorption markers and calcium were significantly elevated at all time points after bed rest (P < 0.01). CONCLUSIONS: In healthy men subjected to controlled bed rest for 90 d, serum sclerostin increased, with a peak at 60, whereas serum PTH declined, and urinary calcium and bone resorption markers increased.
Assuntos
Repouso em Cama , Proteínas Morfogenéticas Ósseas/sangue , Absorciometria de Fóton , Proteínas Adaptadoras de Transdução de Sinal , Adulto , Biomarcadores/urina , Densidade Óssea , Reabsorção Óssea/metabolismo , Reabsorção Óssea/urina , Osso e Ossos/metabolismo , Cálcio/urina , Marcadores Genéticos , Decúbito Inclinado com Rebaixamento da Cabeça , Humanos , Estudos Longitudinais , Masculino , Hormônio Paratireóideo/sangue , Fósforo/urina , Aptidão Física , Vitamina D/sangueRESUMO
BACKGROUND: Despite frequent clinical use, information about the pharmacokinetics and efficacy of pantoprazole in camelids is not available. OBJECTIVES: To examine the pharmacokinetics of both IV and SC pantoprazole and to determine whether pantoprazole administration would increase 3rd compartment pH in alpacas. ANIMALS: Six healthy adult alpacas. METHODS: Alpacas were fitted with a 3rd compartment cannula for measuring gastric pH. After recovery, alpacas received 1 mg/kg pantoprazole IV, q24h for 3 days or 2 mg/kg SC q24h for 3 days. Alpacas received both IV and SC pantoprazole, with a minimum of 3 weeks between treatments. Third compartment pH was recorded and plasma samples were taken for pharmacokinetic analysis. RESULTS: Pantoprazole induced a slow but sustained increase in 3rd compartment pH when given by both the IV and SC routes. Third compartment pH was significantly increased as compared with baseline values (1.81+/-0.7; mean+/-SD) at 24 (2.47+/-0.8), 48 (3.53+/-1.0) and 72 hours (4.03+/-1.3) after daily IV administration of pantoprazole. Third compartment pH increased from 1.73+/-0.6 at baseline to 3.05+/-1.1, 4.02+/-1.4, and 3.61+/-1.6 at 24, 48, and 72 hours after SC administration, respectively. Pharmacokinetic analysis demonstrated that pantoprazole had a short elimination half-life (0.47+0.06 h) and a high clearance rate (12.2+/-2.9 mL/kg/min) after both IV and SC administration. CONCLUSIONS AND CLINICAL RELEVANCE: Based on the results of this study, pantoprazole represents a safe and effective drug for increasing 3rd compartment pH in camelids. Either IV or SC administration is likely to be an effective treatment for gastric ulcers.
Assuntos
2-Piridinilmetilsulfinilbenzimidazóis/farmacocinética , 2-Piridinilmetilsulfinilbenzimidazóis/uso terapêutico , Antiulcerosos/farmacocinética , Antiulcerosos/uso terapêutico , Camelídeos Americanos , Úlcera Gástrica/veterinária , Animais , Concentração de Íons de Hidrogênio , Pantoprazol , Úlcera Gástrica/prevenção & controleRESUMO
Maintaining an intact nutrient supply in the food system flown on spacecraft is a critical issue for mission success and crew health. Ground-based evidence indicates that some vitamins may be altered and fatty acids oxidized (and therefore rendered useless, or even dangerous) by long-term storage and by exposure to radiation, both of which will be issues for long-duration exploration missions in space. In this study, the stability of nutrients was investigated in food samples exposed to spaceflight on the Intl. Space Station (ISS). A total of 6 replicates of 5 different space food items, a multivitamin, and a vitamin D supplement were packaged into 4 identical kits and were launched in 2006 on the space shuttle. After 13, 353, 596, and 880 d of spaceflight aboard the ISS, the kits were returned to Earth. Nine replicates of each food item and vitamin, from the same lots as those sent into space, remained in an environmental chamber on Earth to serve as controls at each time point. Vitamins, hexanal, oxygen radical absorbance capacity, and amino acids were measured in identical-lot food samples at each time point. After 596 d of spaceflight, differences in intact vitamin concentrations due to duration of storage were observed for most foodstuffs, but generally, nutrients from flight samples did not degrade any faster than ground controls. This study provided the 1st set of spaceflight data for investigation of nutrient stability in the food system, and the results will help NASA design food systems for both ISS and space exploration missions.
Assuntos
Suplementos Nutricionais/análise , Análise de Alimentos , Manipulação de Alimentos/métodos , Voo Espacial , Aldeídos/análise , Aminoácidos/análise , Animais , Radiação Cósmica , Suplementos Nutricionais/efeitos da radiação , Alimentos/efeitos da radiação , Estado Nutricional , Espécies Reativas de Oxigênio , Fatores de Tempo , Vitaminas/análiseRESUMO
The Restoring Health Program, a multi-disciplinary model of care for patients with chronic lung diseases, heart failure, and diabetes, was established to improve the quality of life and function for patients with these target chronic diseases, while reducing their disproportionately high demand on acute health care services. Acute health care utilization at St Vincent's Hospital Melbourne for all patients recruited between February 2003 and June 2005 (n = 351) was analyzed using within-subjects paired sample t-tests to compare the 6 months of pre-recruitment with 6 months of post-recruitment. Analysis showed statistically significant decreases in emergency department presentations (P < 0.001), hospital admissions (P < 0.001), and length of stay (P < 0.001). This article describes the current model of care, the program's enablers, and its impact on health service demand after the first 4 years of implementation.
Assuntos
Diabetes Mellitus/reabilitação , Serviço Hospitalar de Emergência/estatística & dados numéricos , Insuficiência Cardíaca/reabilitação , Doença Pulmonar Obstrutiva Crônica/reabilitação , Qualidade de Vida , Idoso , Doença Crônica , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Programas Nacionais de Saúde , Equipe de Assistência ao Paciente/organização & administração , VitóriaRESUMO
Functionally significant landmarks in the brain do not necessarily align with local sulcal and gyral architecture in a manner that is consistent across individuals. However, the functional specialisation underlying these landmarks is strongly constrained by the connectional architecture of the region. Here, we explore this relationship in the supplementary motor area (SMA) and pre-SMA in the medial frontal cortex of the human brain. Using diffusion tensor, conventional and functional MR imaging, we find that the location of the functional boundary between SMA and preSMA is more consistent with respect to specific features of the local white matter as it approaches neocortex than with respect to the local gyral and sulcal anatomy in the region.
Assuntos
Imagem de Difusão por Ressonância Magnética , Lobo Frontal/fisiologia , Aumento da Imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Córtex Motor/fisiologia , Vias Neurais/fisiologia , Oxigênio/sangue , Adulto , Mapeamento Encefálico , Imagem Ecoplanar , Feminino , Lobo Frontal/anatomia & histologia , Humanos , Masculino , Córtex Motor/anatomia & histologia , Vias Neurais/anatomia & histologia , Tratos Piramidais/anatomia & histologia , Tratos Piramidais/fisiologia , Valores de Referência , Tálamo/anatomia & histologia , Tálamo/fisiologiaRESUMO
High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.
Assuntos
Aminoácidos Essenciais/administração & dosagem , Aminoácidos Essenciais/efeitos adversos , Reabsorção Óssea/induzido quimicamente , Reabsorção Óssea/metabolismo , Calcificação Fisiológica/efeitos dos fármacos , Suplementos Nutricionais/efeitos adversos , Simulação de Ausência de Peso/efeitos adversos , Adulto , Fosfatase Alcalina/sangue , Aminoácidos/urina , Cálcio/metabolismo , Colágeno/urina , Colágeno Tipo I , Humanos , Masculino , Peptídeos/urinaRESUMO
There have been a limited number of randomised controlled trials carried out in Irish general practice. This paper presents an overview of the particular issues involved, based on a recently completed randomised controlled trial of diabetes shared care. Study design, ethical considerations, practice and patient related factors including recruitment and barriers to participation and the role of parallel economic and qualitative analyses are considered with a view to informing future study design.
Assuntos
Prestação Integrada de Cuidados de Saúde , Diabetes Mellitus Tipo 2/terapia , Medicina de Família e Comunidade , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Humanos , Irlanda , Avaliação de Processos e Resultados em Cuidados de SaúdeRESUMO
A fully probabilistic framework is presented for estimating local probability density functions on parameters of interest in a model of diffusion. This technique is applied to the estimation of parameters in the diffusion tensor model, and also to a simple partial volume model of diffusion. In both cases the parameters of interest include parameters defining local fiber direction. A technique is then presented for using these density functions to estimate global connectivity (i.e., the probability of the existence of a connection through the data field, between any two distant points), allowing for the quantification of belief in tractography results. This technique is then applied to the estimation of the cortical connectivity of the human thalamus. The resulting connectivity distributions correspond well with predictions from invasive tracer methods in nonhuman primate.
Assuntos
Imagem de Difusão por Ressonância Magnética , Algoritmos , Anisotropia , Humanos , Processamento de Imagem Assistida por Computador , Modelos Estatísticos , Tálamo/anatomia & histologiaRESUMO
Evidence concerning anatomical connectivities in the human brain is sparse and based largely on limited post-mortem observations. Diffusion tensor imaging has previously been used to define large white-matter tracts in the living human brain, but this technique has had limited success in tracing pathways into gray matter. Here we identified specific connections between human thalamus and cortex using a novel probabilistic tractography algorithm with diffusion imaging data. Classification of thalamic gray matter based on cortical connectivity patterns revealed distinct subregions whose locations correspond to nuclei described previously in histological studies. The connections that we found between thalamus and cortex were similar to those reported for non-human primates and were reproducible between individuals. Our results provide the first quantitative demonstration of reliable inference of anatomical connectivity between human gray matter structures using diffusion data and the first connectivity-based segmentation of gray matter.
Assuntos
Córtex Cerebral/anatomia & histologia , Imagem de Difusão por Ressonância Magnética/métodos , Vias Neurais/anatomia & histologia , Tálamo/anatomia & histologia , Adulto , Mapeamento Encefálico , Córtex Cerebral/fisiologia , Feminino , Humanos , Masculino , Vias Neurais/metabolismo , Probabilidade , Reprodutibilidade dos Testes , Tálamo/fisiologiaRESUMO
Metabolic activation of retinol (vitamin A) via sequential actions of retinol and retinal dehydrogenases produces the active metabolite all-trans-retinoic acid. This work reports cDNA cloning, enzymatic characterization, function in a reconstituted path of all-trans-retinoic acid biosynthesis in cell culture, and mRNA expression patterns in adult tissues and embryos of a mouse retinol dehydrogenase, RDH1. RDH1 represents a new member of the short chain dehydrogenase/reductase superfamily that differs from other mouse RDH in relative activity with all-trans and cis-retinols. RDH1 has a multifunctional catalytic nature, as do other short chain dehydrogenase/reductases. In addition to retinol dehydrogenase activity, RDH1 has strong 3alpha-hydroxy and weak 17beta-hydroxy steroid dehydrogenase activities. RDH1 has widespread and intense mRNA expression in tissues of embryonic and adult mice. The mouse embryo expresses RDH1 as early as 7.0 days post-coitus, and expression is especially intense within the neural tube, gut, and neural crest at embryo day 10.5. Cells cotransfected with RDH1 and any one of three retinal dehydrogenase isozymes synthesize all-trans-retinoic acid from retinol, demonstrating that RDH1contributes to a path of all-trans-retinoic acid biosynthesis in intact cells. These characteristics are consistent with RDH1 functioning in a path of all-trans-retinoic acid biosynthesis starting early during embryogenesis.
Assuntos
Oxirredutases do Álcool/metabolismo , Hidroxiesteroide Desidrogenases/metabolismo , Vitamina A/metabolismo , Oxirredutases do Álcool/química , Oxirredutases do Álcool/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Clonagem Molecular , DNA Complementar , Embrião de Mamíferos/metabolismo , Hidroxiesteroide Desidrogenases/química , Hidroxiesteroide Desidrogenases/genética , Hibridização In Situ , Cinética , Camundongos , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
The effects of surface (aboveground) and peat (belowground) fire on a number of soil constituents were examined within a hydrologically altered marsh in the northern Florida Everglades. Peat fire resulted in losses of total carbon (TC), total nitrogen (TN), and organic phosphorus (Po), while inorganic phosphorus (Pi) and total calcium (TCa) concentrations increased. In addition, peat fire led to a more pronounced vertical gradient in constituent concentrations between upper and lower soil layers. Surface fire also affected soil constituents, but impacts were small relative to peat fire. The effects of physical versus chemical processes during burning were assessed using ratios of constituent to TCa concentrations. This measure indicated that increases in the levels of total phosphorus (TP) in peat-burned areas were due primarily to the physical reduction of soil, while decreases in TN and TC were the result of volatilization. Increases in concentrations of Pi fractions arose from both chemically and physically mediated processes. In an ecological context, the observed soil transformations may encourage the growth of invasive plant species, such as southern narrow-leaved cattail (Typha domingensis Pers.), which exhibits high growth rates in response to increased P availability.
Assuntos
Ecossistema , Incêndios , Solo , Disponibilidade Biológica , Cálcio/análise , Monitoramento Ambiental , Fósforo/análise , Plantas , Poaceae , Dinâmica PopulacionalRESUMO
Potato D-enzyme catalyses an intramolecular transglycosylation reaction on amylose to produce cycloamylose, a novel cyclic alpha-1, 4 glucan. To determine if a similar activity could be observed with a high molecular weight branched substrate, recombinant potato D-enzyme was incubated with amylopectin. The substrate was converted into two fractions of lower molecular mass. Fraction I comprised 15% cyclic molecules of which the majority contained both alpha-1,4 and alpha-1,6 links. These were shown to be branched molecules with branches shorter than those in amylopectin. Fraction II comprised 80% cyclic molecules of which the majority contained only alpha-1,4 links (cycloamylose). Since fraction II appeared before fraction I, we propose that D-enzyme first catalysed the cyclisation of the outer side chains of amylopectin and then the cyclisation of inner chains to produce branched clusters. These results demonstrate that D-enzyme can catalyse the transfer of branched glucans, and suggest novel ways in which it may participate in starch metabolism in plants.
Assuntos
Amilopectina/metabolismo , Glucanos/biossíntese , Sistema da Enzima Desramificadora do Glicogênio/metabolismo , Amilopectina/química , Glucana 1,4-alfa-Glucosidase/metabolismo , Glucanos/química , Glicosilação , Modelos Biológicos , Peso Molecular , Plantas/metabolismo , Solanum tuberosum/enzimologia , Amido/metabolismoRESUMO
RXRalpha null mutant mice display ocular and cardiac malformations, liver developmental delay, and die from cardiac failure around embryonic day (E) 14.5 pc. To dissect the molecular basis of the RXRalpha-associated cardiomyopathy, we performed subtractive hybridization and systematically characterized putative downstream target genes that were selectively lacking in the mutant embryos, both at early (E10.5) and late (E13.5) stages of mouse embryonic development. Approximately 50% of the subtracted clones (61/115) encoded proteins involved in intermediary metabolism and electron transport, suggesting an energy deficiency in the RXRalpha-/- embryos. In particular, clone G1, which encodes subunit 14.5b of the NADH-ubiquinone dehydrogenase complex, displayed a dose-dependent expression in the wild-type, heterozygous and RXRalpha mutant mice. This gene was also downregulated in a retinoid-deficient rat embryo model. ATP content and medium Acyl-CoA dehydrogenase mRNA were lower in RXRalpha mutant hearts compared to wild-type mice. Ultrastructural studies showed that the density of mitochondria per myocyte was higher in the RXRalpha mutant compared to wild-type littermates. We propose a model whereby defects in intermediary metabolism may be a causative factor of the RXRalpha-/- phenotype and resembles an embryonic form of dilated cardiomyopathy.
Assuntos
Cardiomiopatia Dilatada/embriologia , Metabolismo Energético/genética , Genes/fisiologia , Coração/embriologia , Receptores do Ácido Retinoico/fisiologia , Fatores de Transcrição/fisiologia , Acil-CoA Desidrogenase , Acil-CoA Desidrogenases/genética , Trifosfato de Adenosina/análise , Animais , Cardiomiopatia Dilatada/genética , Clonagem Molecular/métodos , DNA Complementar/genética , Complexo I de Transporte de Elétrons , Regulação da Expressão Gênica no Desenvolvimento , Biblioteca Gênica , Genes/genética , Camundongos , Camundongos Knockout , Mitocôndrias Cardíacas , Miocárdio/química , Miocárdio/citologia , Miocárdio/metabolismo , Miocárdio/ultraestrutura , NADH NADPH Oxirredutases/genética , RNA Mensageiro/análise , Ratos , Ratos Mutantes , Receptores do Ácido Retinoico/genética , Receptores X de Retinoides , Retinoides , Fatores de Transcrição/genéticaRESUMO
Potato D-enzyme was purified from recombinant Escherichia coli, and its action on synthetic amylose (average Mr of 320,000) was analyzed. D-enzyme treatment resulted in a decrease in the ability of the amylose to form a blue complex with iodine. Analysis of the products indicated that the enzyme catalyzes an intramolecular transglycosylation reaction on amylose to produce cyclic alpha-1,4-glucan (cycloamylose). Confirmation of the cyclic structure was achieved by demonstrating the absence of reducing and nonreducing ends, resistance to hydrolysis by glucoamylase (an exoamylase), and by "time of flight" mass spectrometry. The degree of polymerization of cycloamylose products was determined by time of flight mass spectrometry analysis and by high-performance anion-exchange chromatography following partial acid hydrolysis of purified cycloamylose molecules and was found to range from 17 to several hundred. The yield of cycloamylose increased with time and reached >95%. D-enzyme did not act upon purified cycloamylose, but if glucose was added as an acceptor molecule, smaller cyclic and linear molecules were produced. The mechanism of the cyclization reaction, the possible role of the enzyme in starch metabolism, and the potential applications for cycloamylose are discussed.
Assuntos
Ciclodextrinas/metabolismo , Sistema da Enzima Desramificadora do Glicogênio/metabolismo , Solanum tuberosum/enzimologia , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Ciclodextrinas/química , Ciclodextrinas/isolamento & purificação , Escherichia coli , Sistema da Enzima Desramificadora do Glicogênio/isolamento & purificação , Iodo , Cinética , Modelos Estruturais , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismoRESUMO
New therapies for vancomycin-resistant Enterococcus faecium (VREF) infections are urgently needed. We describe the treatment of 15 patients with VREF infection with quinupristin/dalfopristin (RP 59500), a new injectable streptogramin antibiotic. Primary infections treated were bacteremia (4), urinary tract (4), intraabdominal (5), otitis externa (1), and meningitis (1). Minimum inhibitory concentrations for quinupristin/dalfopristin ranged from 0.5 microgram/ml or less to 2 micrograms/ml, and minimum bactericidal concentrations were greater than 64 micrograms/ml for all VREF isolates tested. Peak serum inhibitory titers following infusion of quinupristin/dalfopristin ranged from 1:8 to 1:64; all bactericidal titers were less than 1:2. Development of resistance to quinupristin/dalfopristin during therapy was not observed. The only drug-related adverse effect noted was phlebitis in 4 patients; all had received quinupristin/dalfopristin by peripheral venous infusion. Three patients had clinical and bacteriologic cures. Relapses occurred in 5 patients with recovery of VREF from infected sites in post-treatment cultures. Ten patients died of severe underlying disease; VREF was believed to contribute directly to the death of only 1 patient. While evaluation of clinical efficacy was complicated by the severity of underlying disease in patients with VREF infection, our experience suggests that quinupristin/dalfopristin is a safe and potentially useful agent for the treatment of VREF infections.
Assuntos
Antibacterianos , Antibacterianos/uso terapêutico , Enterococcus faecium/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Vancomicina , Virginiamicina/uso terapêutico , Adulto , Idoso , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , DNA Bacteriano/análise , DNA Bacteriano/biossíntese , DNA Bacteriano/isolamento & purificação , Resistência Microbiana a Medicamentos , Eletroforese em Gel de Poliacrilamida , Feminino , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Injeções Intravenosas , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Vancomicina/farmacologia , Virginiamicina/administração & dosagem , Virginiamicina/farmacologiaRESUMO
The effects of immunosuppressant blockers of calcineurin (protein phosphatase 2B) on cAMP formation and hormone release were investigated in mouse pituitary tumor (AtT20) cells. Immunosuppressants enhanced corticotropin-releasing factor- and isoproterenol-evoked cAMP production in proportion with their potency to block calcineurin. Further analysis of cAMP production revealed that intracellular Ca2+ derived through voltage-regulated calcium channels reduces cAMP formation induced by corticotropin releasing-factor or beta 2-adrenergic stimulation and that this effect of Ca2+ is inhibited by blockers of calcineurin. AtT20 cells were found to express at least three species of adenylyl cyclase mRNA-encoding types 1 and 6 as well as a novel isotype, which appeared to be the predominant species. In two cell lines expressing very low or undetectable levels of the novel cyclase mRNA (NCB20 and HEK293 cells respectively), corticotropin-releasing factor-induced cAMP formation was not altered upon blockage of calcineurin activity. These data identify calcineurin as a Ca2+ sensor that mediates the negative feedback effect of intracellular Ca2+ on receptor-stimulated cAMP production. Furthermore, the effect of calcineurin on cAMP synthesis appears to be associated with the expression of a novel adenylyl cyclase isotype, which is highly abundant in AtT20 cells.
Assuntos
1-Metil-3-Isobutilxantina/farmacologia , Adenilil Ciclases/biossíntese , Agonistas Adrenérgicos beta/farmacologia , Canais de Cálcio/fisiologia , Cálcio/metabolismo , Proteínas de Ligação a Calmodulina/antagonistas & inibidores , AMP Cíclico/metabolismo , Isoproterenol/farmacologia , Fosfoproteínas Fosfatases/antagonistas & inibidores , Sequência de Aminoácidos , Animais , Sequência de Bases , Calcineurina , Canais de Cálcio/efeitos dos fármacos , Linhagem Celular , Sequência Conservada , Hormônio Liberador da Corticotropina/farmacologia , Ciclosporinas/farmacologia , Primers do DNA , DNA Complementar , Retroalimentação , Humanos , Imunossupressores/farmacologia , Isoenzimas/biossíntese , Cinética , Camundongos , Dados de Sequência Molecular , Adeno-Hipófise , Neoplasias Hipofisárias , Reação em Cadeia da Polimerase , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , Homologia de Sequência de Aminoácidos , Tacrolimo/farmacologia , Células Tumorais CultivadasRESUMO
The isolation of clinical strains of enterococci requiring vancomycin for growth has only recently been reported. We describe the isolation of Enterococcus faecium requiring vancomycin for growth from the stool of a patient who had completed oral vancomycin therapy. Growth of the vancomycin-dependent E. faecium was supported by ristocetin and D-alanyl-D-alanine but not by daptomycin, teicoplanin, or D,L-alanine. Spontaneous revertants not requiring vancomycin occurred at a rate of 1 in 10(6). Both the vancomycin-dependent E. faecium and the revertant hybridized with a vanB gene probe and had identical contour-clamped homogeneous electrophoresis patterns. The majority of revertant colonies were resistant to teicoplanin, suggesting constitutive production of the vanB ligase. We believe the vancomycin-dependent E. faecium evolved from a vancomycin-resistant, vancomycin-independent E. faecium in the presence of high concentrations of vancomycin in the intestine.
Assuntos
Enterococcus faecium/crescimento & desenvolvimento , Fezes/microbiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Vancomicina/metabolismo , Idoso , Idoso de 80 Anos ou mais , DNA Bacteriano , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/genética , Enterococcus faecium/isolamento & purificação , Enterocolite Pseudomembranosa/complicações , Enterocolite Pseudomembranosa/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/complicações , Humanos , Masculino , Testes de Sensibilidade Microbiana , Vancomicina/uso terapêuticoRESUMO
Male Sprague-Dawley rats were fed a diet high in either saturated fat (lard) or polyunsaturated fat (corn oil) beginning at 10 weeks of age. After 10 weeks of diet treatment, blood pressure (BP) was 17% higher in rats fed saturated fat and 8% higher in rats fed polyunsaturated fat than in rats fed a low-fat control diet. Rats fed the lard diet became obese, and their fasting insulin levels were elevated (38% above control). These data demonstrate that both saturated and polyunsaturated dietary fats induce hypertension.