We have studied the kinetics of hydrolysis of triacylglycerols, vinyl esters and
p-nitrophenyl butyrate by four carboxylesterases of the HSL family, namely recombinant human hormone-sensitive lipase ...(HSL), EST2 from
Alicyclobacillus acidocaldarius, AFEST from
Archeoglobus fulgidus, and protein RV1399C from Mycobacterium tuberculosis. The kinetic properties of enzymes of the HSL family have been compared to those of a series of lipolytic and non-lipolytic carboxylesterases including human pancreatic lipase, guinea pig pancreatic lipase related protein 2, lipases from
Mucor miehei and
Thermomyces lanuginosus, cutinase from
Fusarium solani, LipA from
Bacillus subtilis, porcine liver esterase and Esterase A from
Aspergilus niger. Results indicate that human HSL, together with other lipolytic carboxylesterases, are active on short chain esters and hydrolyze water insoluble trioctanoin, vinyl laurate and olive oil, whereas the action of EST2, AFEST, protein RV1399C and non-lipolytic carboxylesterases is restricted to solutions of short chain substrates. Lipolytic and non-lipolytic carboxylesterases can be differentiated by their respective value of
K
0.5 (apparent
K
m) for the hydrolysis of short chain esters. Among lipolytic enzymes, those possessing a lid domain display higher activity on tributyrin, trioctanoin and olive oil suggesting, then, that the lid structure contributes to enzyme binding to triacylglycerols. Progress reaction curves of the hydrolysis of
p-nitrophenyl butyrate by lipolytic carboxylesterases with lid domain show a latency phase which is not observed with human HSL, non-lipolytic carboxylesterases, and lipolytic enzymes devoid of a lid structure as cutinase.
Hormone-sensitive lipase (HSL) is thought to contribute importantly to the mobilization of fatty acids from the triacylglycerols (TAGs) stored in adipocytes, providing the main source of energy in ...mammals. To investigate the HSL substrate specificity more closely, we systematically assessed the lipolytic activity of recombinant human HSL on solutions and emulsions of various vinyl esters and TAG substrates, using the pH-stat assay technique. Recombinant human HSL activity on solutions of partly soluble vinyl esters or TAG was found to range from 35 to 90% of the maximum activity measured with the same substrates in the emulsified state. The possible existence of a lipid−water interface due to the formation of small aggregates of vinyl esters or TAG in solution may account for the HSL activity observed below the solubility limit of the substrate. Recombinant human HSL also hydrolyzes insoluble medium- and long-chain acylglycerols such as trioctanoylglycerol, dioleoylglycerol, and olive oil, and can therefore be classified as a true lipase. Preincubation of the recombinant HSL with a serine esterase inhibitor such as diethyl p-nitrophenyl phosphate in 1:100 molar excess leads to complete HSL inhibition within 15 min. This result indicates that the catalytic serine of HSL is highly reactive and that it is readily accessible. Similar behavior was also observed with lipases with no lid domain covering their active site, or with a deletion in the lid domain. The 3-D structure of HSL, which still remains to be determined, may therefore lack the lid domain known to exist in various other lipases.
An approach for tracing the origin of submerged entry nozzle (SEN) clogging that occurs during continuous casting of Al-killed steel is presented. This approach consists of using stable oxygen ...isotope ratios. IR laser fluorination in combination with gas mass spectroscopy is performed to determine the oxygen isotope composition of alumina-rich precipitates (clogging) and possible oxygen sources like refractory materials, slags, process and atmospheric oxygen. Three oxygen sources for clogging are identified. A quantitative model is presented.
For facilitation of the experimental analysis of the mechanism and regulation of mobilization of fatty acids from adipose triacylglycerol (TAG) stores, which also represents important targets for ...pharmacological intervention with the pathogenesis of diabetes and obesity, we developed a convenient and reliable non-radioactive cell-based assay. Isolated rat adipocytes are incubated with the fluorescent fatty acid derivative, 12-((7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoic acid (NBD-FA), in the presence of insulin. The resulting NBD-FA-labeled TAG is efficiently cleaved by hormone-sensitive lipase (HSL) in vitro. After removal of insulin and excess of free NBD-FA, lipolysis is initiated by addition of isoproterenol and/or adenosine deaminase. The amount of NBD-FA generated in total or released into the incubation medium in the presence of modulatory hormones or compounds is then monitored by thin layer chromatography and fluorescence imaging. Release of NBD-FA, glycerol and
3Holeic acid from TAG follows similar kinetics and concentration dependence in response to various lipolytic and anti-lipolytic stimuli as well as inhibitors of HSL. Release of NBD-FA from adipocytes correlates well to translocation of HSL from the cytosol to TAG droplets. In addition, we found that a cell-free system consisting of NBD-FA-labeled TAG droplets with endogenous associated HSL closely reflects the lipolytic state of the adipocytes used for its preparation. In conclusion, release of NBD-FA from TAG in vivo and in vitro can be used as accurate index for (regulation of) lipolysis in primary and cultured adipocytes.
Chlorogenic acid derivatives are potent inhibitors of hepatic glucose production by inhibition of the glucose-6-phosphate translocase component of the hepatic glucose-6-phosphatase system. The ...pharmacological proof of concept was clearly demonstrated during i.v. infusion of potent derivatives (S 4048, S 3483) in rats. However, the blood glucose lowering effect of S 4048 after bolus i.v. injection lasted only 60–90 min. Plasma clearance of S 4048 was very high, and the parent compound was rapidly and efficiently excreted into the bile of Wistar and GY/TR
− rats, indicating that mrp-2 was not involved in this hepatobiliary elimination process. About 72% of the total administered radioactivity appeared in the bile within 20 min after i.v. bolus injection of the radiolabeled analogue
3HS 1743 in a Wistar rat. However, in GY/TR
− rats the dicarboxylic analogue of S 4048, S 3025, was cleared from the plasma less rapidly than its parent compound and its biliary elimination was comparatively low. In contrast, S 3025 exhibited comparable pharmacokinetics and biliary elimination profile as S 4048 in Wistar rats, suggesting that biliary elimination of S 3025 is facilitated by mrp-2, functionally absent in GY/TR
− rats. Targeting to mrp-2 resulted in a significantly prolonged reduction of blood glucose levels in GY/TR
− rats after i.v. bolus administration of S 3025.
RESUMEN Objetivo: agrupar y sintetizar los estudios que abordan la enseñanza de las Infecciones de Transmisión Sexual Incurables para los estudiantes de grado en enfermería a nivel mundial ...(1989-2020). Método: revisión de alcance según los lineamientos del Instituto Joanna Briggs. Estrategia de búsqueda realizada en PubMed, CINAHL, Embase, Web of Science y LILACS. Dos revisores realizaron la selección y extracción de datos de forma independiente. Resultados: después de buscar y eliminar duplicados, 41 estudios cumplieron con los criterios establecidos y fueron incluidos. El análisis de contenido dio como resultado tres categorías: Escenarios y Estrategias de Enseñanza; Foco de la Enseñanza; y Eficacia de la Enseñanza. Consideraciones finales: las acciones educativas fueron efectivas para aumentar el conocimiento, reducir el estigma y la ansiedad y aumentar la sensibilidad para promover el cuidado de enfermería. La enseñanza de este tema es importante para el desempeño de la profesión para los índices epidemiológicos y la formación de los estudiantes de enfermería para la prevención y promoción de la salud.
RESUMO Objetivo: agrupar e sintetizar os estudos que abordam o ensino das Infecções Sexualmente Transmissíveis Incuráveis para estudantes de graduação em enfermagem no mundo (1989-2020). Método: revisão de escopo conforme Instituto Joanna Briggs. Estratégia de busca realizada na PubMed, CINAHL, Embase, Web of Science e LILACS. Dois revisores realizaram seleção e extração dos dados de forma independente. Resultados: após busca e remoção de duplicatas, 41 estudos estavam de acordo com os critérios estabelecidos e foram incluídos. A análise de conteúdo resultou em três categorias: Cenários e Estratégias de Ensino; Foco do Ensino; e Efetividade do Ensino. Considerações finais: as ações educativas tiveram efetividade no aumento do conhecimento, diminuição do estigma e ansiedade, e aumento da sensibilidade em promover o cuidado de enfermagem. O ensino dessa temática se mostra importante na atuação da profissão sobre os índices epidemiológicos e na formação dos estudantes de enfermagem para prevenção e promoção em saúde.
ABSTRACT Objective: to group and synthesize the studies that address the teaching of Incurable Sexually Transmitted Infections for undergraduate Nursing students in the world (1989-2020). Method: a scoping review according to the Joanna Briggs Institute. The search strategy was carried out in PubMed, CINAHL, Embase, Web of Science and LILACS. Two reviewers selected and extracted the data independently. Results: after searching and removing duplicates, 41 studies met the established criteria and were included. Content analysis resulted in three categories: Teaching Scenarios and Strategies; Teaching Focus; and Teaching Effectiveness. Final considerations: the educational actions were effective in increasing knowledge, reducing stigma and anxiety, and increasing sensitivity in promoting Nursing care. Teaching this theme is important in the profession’s work on epidemiological indices and in the training of Nursing students for prevention and promotion in health.
The glucose-6-phosphatase system catalyses the terminal step of hepatic glucose production from both gluconeogenesis and glycogenolysis and is thus a key regulatory factor of blood glucose ...homoeostasis. To identify the glucose 6-phosphate transporter T1, we have performed photoaffinity labelling of human and rat liver microsomes by using the specific photoreactive glucose-6-phosphate translocase inhibitors S 0957 and S 1743. Membrane proteins of molecular mass 70, 55, 33 and 31 kDa were labelled in human microsomes by 3HS 0957, whereas in rat liver microsomes bands at 95, 70, 57, 54, 50, 41, 33 and 31 kDa were detectable. The photoprobe 3HS 1743 led to the predominant labelling of a 57 kDa and a 50 kDa protein in the rat. Stripping of microsomes with 0.3% CHAPS retains the specific binding of T1 inhibitors; photoaffinity labelling of such CHAPS-treated microsomes resulted in the labelling of membrane proteins of molecular mass 55, 33 and 31 kDa in human liver and 50, 33 and 31 kDa in rat liver. Photoaffinity labelling of human liver tissue samples from a healthy individual and from liver samples of patients with a diagnosed glycogen-storage disease type 1b (GSD type 1b; von Gierke's disease) revealed the absence of the 55 kDa protein from one of the patients with GSD type 1. These findings support the identity of the glucose 6-phosphate transporter T1, with endoplasmic reticulum protein of molecular mass 50 kDa in rat liver and 55 kDa in human liver.
The glucose-6-phosphatase system catalyses the terminal step of hepatic glucose production from both gluconeogenesis and glycogenolysis and is thus a key regulatory factor of blood glucose ...homoeostasis. To identify the glucose 6-phosphate transporter T1, we have performed photoaffinity labelling of human and rat liver microsomes by using the specific photoreactive glucose-6-phosphate translocase inhibitors S 0957 and S 1743. Membrane proteins of molecular mass 70, 55, 33 and 31 kDa were labelled in human microsomes by 3HS 0957, whereas in rat liver microsomes bands at 95, 70, 57, 54, 50, 41, 33 and 31 kDa were detectable. The photoprobe 3HS 1743 led to the predominant labelling of a 57 kDa and a 50 kDa protein in the rat. Stripping of microsomes with 0.3% CHAPS retains the specific binding of T1 inhibitors; photoaffinity labelling of such CHAPS-treated microsomes resulted in the labelling of membrane proteins of molecular mass 55, 33 and 31 kDa in human liver and 50, 33 and 31 kDa in rat liver. Photoaffinity labelling of human liver tissue samples from a healthy individual and from liver samples of patients with a diagnosed glycogen-storage disease type 1b (GSD type 1b; von Gierke's disease) revealed the absence of the 55 kDa protein from one of the patients with GSD type 1. These findings support the identity of the glucose 6-phosphate transporter T1, with endoplasmic reticulum protein of molecular mass 50 kDa in rat liver and 55 kDa in human liver.
A method of stepwise chemical degradation was elaborated on a microgram quantity of 3-O-alpha-L-fucosyllactose. The key step, TiCl4-catalysed dithioacetal formation from the permethylated ...N-4-nitrophenyl triosylamine (4) was accompanied by quantitative defucosylation. 14CAcetylation of the dried mercaptalation mixture gave radiolabelled 3,5-di-O-14Cacetyl-4-O-(2,3,4,6-tetra-O-methyl-beta-D-galactopyranosyl )-2 , 6-di-O-methyl-D-glucose diethyl dithioacetal (7) and 5-O-14Cacetyl-2,3,4-tri-O-methyl-L-fucose diethyl dithioacetal (8). The former was further degraded via the bis(sulfone), and thereby 2,3,4,6-tetra-O-methyl-D-galactose (13) was expelled. The monosaccharide branches, fucose and galactose, were identified as derivatives 8 and 13, respectively, by comparison with authentic samples. Isolation of microquantities of products was carried out by preparative TLC.
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