266 research outputs found
Metode i važnost ispitivanja oksidacije biljnih ulja, masti i lipoproteina pomoću lipaze pankreasa i arilesteraze
Fats and oils as major dietary components are involved in the development of chronic diseases. In this paper the physiological relevance and some methodological aspects related to the determination of two enzymes enrolled in metabolism of fat – pancreatic lipase and arylesterase – are discussed. Pancreatic lipase has been extensively used to study the triacylglycerol fatty acid composition and the in vitro digestion of oils and fats. The action of this enzyme may be coupled to analytical methods as GC, HPLC, HPSEC, TLC- -FID, etc. as a useful tool for understanding the composition and digestion of thermal oxidized oils. Pancreatic lipase hydrolysis occurs in the water/oil interface, and it presents a behaviour that seems to be Michaelian, in which the apparent Km and the apparent Vmax of the enzymatic process depend more on the type of oil tested than on the degree of alteration. The kinetic behaviour of pancreatic lipase towards thermally oxidized oils also depends on the presence of natural tensioactive compounds present in the oil and surfactants formed during the frying. Arylesterase is an HDL binding enzyme that inhibits LDL oxidation. Low serum concentration of this enzyme has been related to increased cardiovascular disease risk. In this paper the most widely used methods for the determination of arylesterase activity are commented on. The importance of intrinsic factors (e.g. substrates, cofactors) participating in the enzyme reaction is also discussed. Moreover, several suggestions about further researches on the influence of extrinsic factors (e.g. diet, oxidative stress) upon the enzyme activity are proposed.Masti i ulja, kao glavni sastojci prehrane, uzrok su razvoja nekih kroničnih bolesti. U radu su ispitivani fiziološka važnost i neke metode određivanja dvaju enzima koji sudjeluju u metabolizmu masti, i to lipaze pankreasa i arilesteraze. Lipaza pankreasa vrlo se često koristila u ispitivanju sastava masnih kiselina u triacilglicerolima i u in vitro digestiji ulja i masti. Djelovanje tog enzima može se povezati s analitičkim metodama kao što su GC, HPLC, HPSEC i TLC-FID kako bi se utvrdio sastav i digestija toplinski oksidiranih ulja. Hidrolitsko djelovanje lipaze pankreasa provodi se na granici faza voda/ulje, te se čini da se pokorava Michaelis-Mentenovoj kinetici, u kojoj prividne Km i Vmax vrijednosti enzimskog procesa više ovise o vrsti ispitivanog ulja nego o stupnju hidrolize. Kinetika lipaze pankreasa prema toplinski oksidiranim uljima ovisi također o prisutnosti prirodnih tenzioaktivnih spojeva u ulju i o površinski aktivnim spojevima nastalim tijekom prženja. Arilesteraza je enzim koji veže HDL i time inhibira oksidaciju LDL. Mala koncentracija tog enzima u serumu povezana je s povećanim rizikom kardiovaskularnih bolesti. U radu su prikazane najčešće primijenjeni postupci za određivanje aktivnosti arilesteraze. Ujedno je razmotrena važnost unutarnjih faktora (npr. supstrata, kofaktora) koji sudjeluju u enzimskoj reakciji. Nadalje, predložena su daljnja istraživanja o utjecaju vanjskih faktora (npr. dijeta, oksidativni stres) na aktivnost enzima
Mesoporous silica nanoparticles as a new carrier methodology in the controlled release of the active components in a polypill
Polypill is a medication designed for preventing heart attacks through a combination of drugs. Current formulations contain blood pressure-lowering drugs and others, such statins or acetylsalicylic acid. These drugs exhibit different physical chemical features, and consequently different release kinetics. Therefore, the concentration in plasma of some of them after the release process can be out of the therapeutic range. This paper investigates a new methodology for the control dosage of a polypill recently reported containing hydrochlorothiazide, amlodipine, losartan and simvastatin in a 12.5/2.5/25/40 weight ratio. The procedure is based onmesoporous silica nanoparticles (MSN) with MCM-41 structure (MSN-41) used as carrier, aimed to control release of the four drugs included in the polypill. In vitro release data were obtained by HPLC and the curves adjusted with a kinetic model. To explain the release results, a molecular model was built to determine the drug-matrix interactions, and quantum mechanical calculations were performed to obtain the electrostatic properties of each drug. Amlodipine, losartan and simvastatin were released from the polypill-MSN-41 system in a controlled way. This would be a favourable behavior when used clinically because avoid too quick pressure decrease. However, the diuretic hydrochlorothiazide was quickly released from our system in the first minutes, as is needed in hypertensive urgencies. In addition, an increase in the stability of amlodipine and hydrochlorothiazide occurred in the polypill-MSN-41 system. Therefore, the new way of polypill dosage proposed can result in a safer and effective treatment. (C) 2016 Elsevier B.V. All rights reserved
A molecular model to explain the controlled release from SBA-15 functionalized with APTES
A molecular model with the approximate pore diameter of SBA-15 was constructed for the first time to investigate the effect of functionalize the matrix with 3-aminopropyl-triethoxy-silane (APTES) in the release of Chicago Sky Blue 6B (CSB). It was expected that the positively charged amino groups of APTES could interact with the negatively charged sulphonic groups of CSB allowing controlling the release process. Indeed the experimental study showed that the release kinetics of CSB from SBA-15-APTES is two orders of magnitude smaller than from native SBA-15. However molecular modelling calculations investigating the possible interactions of APTES and SBA-15 yield unexpected results. In the model including only the condensation between the silanol groups of SBA-15 and APTES, the calculated interaction energy of CSB was quite similar than with the model of native SBA-15. However when additional electrostatic interactions of the -NH2 groups of APTES with the mesoporous matrix were modelled the mesoporous channels underwent a considerable deformation. These results point to the structure deformation as the cause of the greater retention of CSB in SBA-15-APTES and warn about the special features of AFTES when used to functionalize mesoporous silica materials. The model built in this paper could be used to construct predictive models in analogous drug delivery systems. (C) 2014 Elsevier Inc. All rights reserved
Willingness to Be Vaccinated against COVID-19 in Spain before the Start of Vaccination: A Cross-Sectional Study
Vaccine hesitancy has increased in the past few years, influenced by the socio-cultural differences, political populism, or concerns related to the effectiveness and safety of some vaccines, resulting a feeling of distrust. This feeling can become a barrier against the achievement of the immunity necessary to stop the expansion of COVID-19. The aim of this study was to evaluate the acceptance of the vaccine against COVID-19 in Spain, as well as to identify the factors that have an influence on the concerns and attitudes of people against accepting the vaccine in the months prior to the start of vaccination on December 2020. An online questionnaire was created to obtain information about (1) sociodemographic characteristics; (2) concerns and sources of information about vaccines; and (3) attitudes about vaccination and state of health. A multivariate logistic regression was performed to identify the influencing factors. Of the 2501 participants, 1207 (48.3%) would accept the COVID-19 vaccine, 623 (24.9%) were hesitant, and 671 (26.8%) would reject it. The logistic regression showed that being male, older than 60, married, retired, with a high level of education, or with a leftist political inclination, could increase the probability of accepting the COVID-19 vaccine. Disinformation and the lack of political consensus were the main sources of distrust. The patients with hypertension, immunodepression, hypercholesterolemia, or respiratory disease, or were overweight, showed a greater acceptance to the vaccine, while those with cancer took the longest to accept it. A low acceptance of the vaccine against COVID-19 was observed among the Spanish population in the phase prior to its availability, and the main fears of the population were identified. It is necessary to offer correct and transparent information about these vaccines to reduce the concerns and increase the trust of the population, to thereby guarantee the success of the vaccination campaigns
Association of meal timing with body composition and cardiometabolic risk factors in young adults
Purpose To investigate the association of meal timing with body composition and cardiometabolic risk factors in young
adults.
Methods In this cross-sectional study participated 118 young adults (82 women; 22 ± 2 years old; BMI: 25.1 ± 4.6 kg/m2).
Meal timing was determined via three non-consecutive 24-h dietary recalls. Sleep outcomes were objectively assessed using
accelerometry. The eating window (time between first and last caloric intake), caloric midpoint (local time at which ≥ 50%
of daily calories are consumed), eating jetlag (variability of the eating midpoint between non-working and working days),
time from the midsleep point to first food intake, and time from last food intake to midsleep point were calculated. Body
composition was determined by DXA. Blood pressure and fasting cardiometabolic risk factors (i.e., triglycerides, total cholesterol,
high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and insulin resistance) were measured.
Results Meal timing was not associated with body composition (p > 0.05). The eating window was negatively related to
HOMA-IR and cardiometabolic risk score in men (R2 = 0.348, β = − 0.605; R2 = 0.234, β = − 0.508; all p ≤ 0.003). The
time from midsleep point to first food intake was positively related to HOMA-IR and cardiometabolic risk score in men
(R2 = 0.212, β = 0.485; R2 = 0.228, β = 0.502; all p = 0.003). These associations remained after adjusting for confounders and
multiplicity (all p ≤ 0.011).
Conclusions Meal timing seems unrelated to body composition in young adults. However, a longer daily eating window and
a shorter time from midsleep point to first food intake (i.e., earlier first food intake in a 24 h cycle) are associated with better
cardiometabolic health in young men.
Clinical trial registration NCT0236512
Current state of biology and diagnosis of clonal mast cell diseases in adults
[EN] Mastocytosis comprises a heterogeneous group of disorders characterized by the presence of clonal mast cells (MC) in organs such as skin, bone marrow (BM), and gastrointestinal tract, among other tissues. The clonal nature of the disease can be established in most adult patients by the demonstration of activating KIT mutations in their BM MC. When highly sensitive techniques capable of identifying cells
present at very low frequencies in a sample are applied, BM MC from virtually all systemic mastocytosis patients display unique immunophenotypical features, particularly the aberrant expression of CD25.
By contrast, large, multifocal BM MC aggregates (the only World Health Organization major criterion for systemic mastocytosis) are absent in a significant proportion of patients fulfilling at least three
minor criteria for systemic mastocytosis, particularly in subjects studied at early stages of the disease with very low MC burden. Moreover, recent molecular and immunophenotypical investigations of BM MC
from patients with indolent systemic mastocytosis have revealed a close association of some biological features (e.g., multilineage involvement of hematopoiesis by the KIT mutation and an immature mast cell
immunophenotype) with an increased risk for disease progression. These observations support the fact that, although the current consensus diagnostic criteria for systemic mastocytosis have been a major advance for the diagnosis and classification of the disease, rationale usage of the most sensitive diagnostic techniques available nowadays is needed to improve the diagnosis, refine the classification, and reach objective prognostic stratification of adult mastocytosis
Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents
Objectives. This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types. Study D esign. Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, and cement type on vertical misfit. The statistical significance was set at ? = 0.05. Results. The alloy/manufacturing technique and the luting cement affected the vertical discrepancy (p < 0.001). For each cement type, LS samples exhibited the best fit (p < 0.01) whereas CC and CT frames were statistically similar. Within each alloy group, PF and RXU provided comparably greater discrepancies than KC, PIC, and DT, which showed no differences. Conclusions. Laser sintering may be an alternative to vacuum-casting of base metals to obtain passive-fitting implant-supported crown copings. The best marginal adaptation corresponded to laser sintered structures luted with glass-ionomer KC, or temporary PIC or DT cements. The highest discrepancies were recorded for Co-Cr and Ti cast frameworks bonded with PF or RXU resinous agents. All groups were within the clinically acceptable misfit range
Differential cytogenetic profile in advanced chronic myeloid leukemia with sequential lymphoblastic and myeloblastic blast crisis
Frequency of additional chromosomal abnormalities in chronic myeloid leukemia (CML) is estimated to be 7% in chronic phase and increases to 40–70% in advanced disease. Progression of CML from chronic phase to accelerated phase or blast crisis is often associated with secondary chromosomal aberrations. We report an exceptional case of CML as debut in lymphoblastic blast crisis and a subsequent progression in myeloblastic blast crisis with rare cytogenetic abnormalities
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