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1.
ESMO Open ; 6(6): 100219, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34924144

RESUMO

BACKGROUND: With the implementation of multidisciplinary treatment and development of multiple novel anticancer drugs in parallel with expanding knowledge of supportive and palliative care, a need for separate training and specialisation in medical oncology emerged. A Global Curriculum (GC) in medical oncology, developed and updated by a joint European Society for Medical Oncology/American Society of Clinical Oncology (ESMO/ASCO) GC Task Force/Working Group (GC WG), greatly contributed to the recognition of medical oncology worldwide. MATERIAL AND METHODS: ESMO/ASCO GC WG carried out a global survey on medical oncology recognition and GC adoption in 2019. RESULTS: Based on our survey, medical oncology is recognised as a separate specialty or sub-specialty in 47/62 (75%) countries participating in the survey; with a great majority of them (39/47, 83%) recognising medical oncology as a standalone specialty. Additionally, in 9 of 62 (15%) countries, medical oncology is trained together with haematology as a specialty in haemato-oncology or together with radiotherapy as a specialty in clinical oncology. As many as two-thirds of the responding countries reported that the ESMO/ASCO GC has been either fully or partially adopted or adapted in their curriculum. It has been adopted in a vast majority of countries with established training in medical oncology (28/41; 68%) and adapted in 12 countries with mixed training in haemato-oncology, clinical oncology or other specialty responsible for training on systemic anticancer treatment. CONCLUSIONS: With 75% of participating countries reporting medical oncology as a separate specialty or sub-specialty and as high as 68% of them reporting on GC adoption, the results of our survey on global landscape are reassuring. Despite a lack of data for some regions, this survey represents the most comprehensive and up-to-date information about recognition of medical oncology and GC adoption worldwide and will allow both societies to further improve the dissemination of the GC and global recognition of medical oncology, thus contributing to better cancer care worldwide.


Assuntos
Antineoplásicos , Oncologia , Currículo , Humanos , Oncologia/educação , Cuidados Paliativos , Inquéritos e Questionários
2.
Gynecol Oncol Rep ; 25: 65-69, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29928684

RESUMO

Eighty-five percent of the incidents and deaths from cervical cancer occur in low and middle income countries. In many of these countries, this is the most common cancer in women. The survivals of the women with gynecologic cancers are hampered by the paucity of prevention, screening, treatment facilities and gynecologic oncology providers. Increasing efforts dedicated to improving education and research in these countries have been provided by international organizations. We describe here the existing educational and research programs that are offered by major international organizations, the barriers and opportunities provided by these collaborations and hope to improve the outcomes of cervical cancer through these efforts.

3.
Nat Commun ; 7: 13332, 2016 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-27824353

RESUMO

Caldera-forming eruptions of island volcanoes generate tsunamis by the interaction of different eruptive phenomena with the sea. Such tsunamis are a major hazard, but forward models of their impacts are limited by poor understanding of source mechanisms. The caldera-forming eruption of Santorini in the Late Bronze Age is known to have been tsunamigenic, and caldera collapse has been proposed as a mechanism. Here, we present bathymetric and seismic evidence showing that the caldera was not open to the sea during the main phase of the eruption, but was flooded once the eruption had finished. Inflow of water and associated landsliding cut a deep, 2.0-2.5 km3, submarine channel, thus filling the caldera in less than a couple of days. If, as at most such volcanoes, caldera collapse occurred syn-eruptively, then it cannot have generated tsunamis. Entry of pyroclastic flows into the sea, combined with slumping of submarine pyroclastic accumulations, were the main mechanisms of tsunami production.

5.
Nature ; 499(7456): 70-3, 2013 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-23823795

RESUMO

Investigations of a variety of continental rifts and margins worldwide have revealed that a considerable volume of melt can intrude into the crust during continental breakup, modifying its composition and thermal structure. However, it is unclear whether the cause of voluminous melt production at volcanic rifts is primarily increased mantle temperature or plate thinning. Also disputed is the extent to which plate stretching or thinning is uniform or varies with depth with the entire continental lithospheric mantle potentially being removed before plate rupture. Here we show that the extensive magmatism during rifting along the southern Red Sea rift in Afar, a unique region of sub-aerial transition from continental to oceanic rifting, is driven by deep melting of hotter-than-normal asthenosphere. Petrogenetic modelling shows that melts are predominantly generated at depths greater than 80 kilometres, implying the existence of a thick upper thermo-mechanical boundary layer in a rift system approaching the point of plate rupture. Numerical modelling of rift development shows that when breakup occurs at the slow extension rates observed in Afar, the survival of a thick plate is an inevitable consequence of conductive cooling of the lithosphere, even when the underlying asthenosphere is hot. Sustained magmatic activity during rifting in Afar thus requires persistently high mantle temperatures, which would allow melting at high pressure beneath the thick plate. If extensive plate thinning does occur during breakup it must do so abruptly at a late stage, immediately before the formation of the new ocean basin.

6.
J Agric Food Chem ; 57(21): 9916-22, 2009 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-19817419

RESUMO

Quantitative control of aroma generation during the Maillard reaction presents great scientific and industrial interest. Although there have been many studies conducted in simplified model systems, the results are difficult to apply to complex food systems, where the presence of other components can have a significant impact. In this work, an aqueous extract of defatted beef liver was chosen as a simplified food matrix for studying the kinetics of the Maillard reaction. Aliquots of the extract were heated under different time and temperature conditions and analyzed for sugars, amino acids, and methylbutanals, which are important Maillard-derived aroma compounds formed in cooked meat. Multiresponse kinetic modeling, based on a simplified mechanistic pathway, gave a good fit with the experimental data, but only when additional steps were introduced to take into account the interactions of glucose and glucose-derived intermediates with protein and other amino compounds. This emphasizes the significant role of the food matrix in controlling the Maillard reaction.


Assuntos
Aldeídos/química , Manipulação de Alimentos , Fígado/química , Carne/análise , Animais , Bovinos , Temperatura Alta , Cinética , Modelos Químicos , Volatilização
7.
Appl Environ Microbiol ; 73(8): 2468-78, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17293511

RESUMO

A new primary model based on a thermodynamically consistent first-order kinetic approach was constructed to describe non-log-linear inactivation kinetics of pressure-treated bacteria. The model assumes a first-order process in which the specific inactivation rate changes inversely with the square root of time. The model gave reasonable fits to experimental data over six to seven orders of magnitude. It was also tested on 138 published data sets and provided good fits in about 70% of cases in which the shape of the curve followed the typical convex upward form. In the remainder of published examples, curves contained additional shoulder regions or extended tail regions. Curves with shoulders could be accommodated by including an additional time delay parameter and curves with tails shoulders could be accommodated by omitting points in the tail beyond the point at which survival levels remained more or less constant. The model parameters varied regularly with pressure, which may reflect a genuine mechanistic basis for the model. This property also allowed the calculation of (a) parameters analogous to the decimal reduction time D and z, the temperature increase needed to change the D value by a factor of 10, in thermal processing, and hence the processing conditions needed to attain a desired level of inactivation; and (b) the apparent thermodynamic volumes of activation associated with the lethal events. The hypothesis that inactivation rates changed as a function of the square root of time would be consistent with a diffusion-limited process.


Assuntos
Desinfecção/métodos , Escherichia coli/fisiologia , Pressão Hidrostática , Viabilidade Microbiana , Modelos Biológicos , Contagem de Colônia Microbiana , Cinética , Temperatura , Fatores de Tempo
8.
Biotechnol Bioeng ; 90(5): 532-42, 2005 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-15816026

RESUMO

The selective separation of whey proteins was studied using colloidal gas aphrons generated from the cationic surfactant cetyl trimethyl ammonium bromide (CTAB). From the titration curves obtained by zeta potential measurements of individual whey proteins, it was expected to selectively adsorb the major whey proteins, i.e., bovine serum albumin, alpha-lactalbumin, and beta-lactoglobulin to the aphrons and elute the remaining proteins (lactoferrin and lactoperoxidase) in the liquid phase. A number of process parameters including pH, ionic strength, and mass ratio of surfactant to protein (M(CTAB)/M(TP)) were varied in order to evaluate their effect on protein separation. Under optimum conditions (2 mmol/l CTAB, M(CTAB)/M(TP) = 0.26-0.35, pH 8, and ionic strength = 0.018 mol/l), 80-90% beta-lactoglobulin was removed from the liquid phase as a precipitate, while about 75% lactoferrin and lactoperoxidase, 80% bovine serum albumin, 95% immunoglobulin, and 65% alpha-lactalbumin were recovered in the liquid fraction. Mechanistic studies using zeta potential measurements and fluorescence spectroscopy proved that electrostatic interactions modulate only partially the selectivity of protein separation, as proteins with similar surface charges do not separate to the same extent between the two phases. The selectivity of recovery of beta-lactoglobulin probably occurs in two steps: the first being the selective interaction of the protein with opposite-charged surfactant molecules by means of electrostatic interactions, which leads to denaturation of the protein and subsequent formation and precipitation of the CTAB-beta-lactoglobulin complex. This is followed by the separation of CTAB-beta-lactoglobulin aggregates from the bulk liquid by flotation in the aphron phase. In this way, CGAs act as carriers which facilitate the removal of protein precipitate.


Assuntos
Compostos de Cetrimônio/química , Fracionamento Químico/métodos , Lactoglobulinas/química , Lactoglobulinas/isolamento & purificação , Leite/química , Tensoativos/química , Animais , Cátions , Bovinos , Cetrimônio , Gases/química , Concentração de Íons de Hidrogênio
9.
Biotechnol Bioeng ; 87(7): 924-9, 2004 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-15334419

RESUMO

Truly continuous solid-state fermentations with operating times of 2-3 weeks were conducted in a prototype bioreactor for the production of fungal (Penicillium glabrum) tannase from a tannin-containing model substrate. Substantial quantities of the enzyme were synthesized throughout the operating periods and (imperfect) steady-state conditions seemed to be achieved soon after start-up of the fermentations. This demonstrated for the first time the possibility of conducting solid-state fermentations in the continuous mode and with a constant noninoculated feed. The operating variables and fermentation conditions in the bioreactor were sufficiently well predicted for the basic reinoculation concept to succeed. However, an incomplete understanding of the microbial mechanisms, the experimental system, and their interaction indicated the need for more research in this novel area of solid-state fermentation.


Assuntos
Reatores Biológicos/microbiologia , Hidrolases de Éster Carboxílico/biossíntese , Hidrolases de Éster Carboxílico/isolamento & purificação , Técnicas de Cultura de Células/métodos , Penicillium/enzimologia , Penicillium/crescimento & desenvolvimento , Taninos/metabolismo , Técnicas de Cultura de Células/instrumentação , Proliferação de Células , Fermentação , Projetos Piloto
10.
Biotechnol Prog ; 20(2): 514-25, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15058997

RESUMO

The recovery of lactoferrin and lactoperoxidase from sweet whey was studied using colloidal gas aphrons (CGAs), which are surfactant-stabilized microbubbles (10-100 microm). CGAs are generated by intense stirring (8000 rpm for 10 min) of the anionic surfactant AOT (sodium bis-2-ethylhexyl sulfosuccinate). A volume of CGAs (10-30 mL) is mixed with a given volume of whey (1-10 mL), and the mixture is allowed to separate into two phases: the aphron (top) phase and the liquid (bottom) phase. Each of the phases is analyzed by SDS-PAGE and surfactant colorimetric assay. A statistical experimental design has been developed to assess the effect of different process parameters including pH, ionic strength, the concentration of surfactant in the CGAs generating solution, the volume of CGAs and the volume of whey on separation efficiency. As expected pH, ionic strength and the volume of whey (i.e. the amount of total protein in the starting material) are the main factors influencing the partitioning of the Lf.Lp fraction into the aphron phase. Moreover, it has been demonstrated that best separation performance was achieved at pH = 4 and ionic strength = 0.1 mol/L i.e., with conditions favoring electrostatic interactions between target proteins and CGAs (recovery was 90% and the concentration of lactoferrin and lactoperoxidase in the aphron phase was 25 times higher than that in the liquid phase), whereas conditions favoring hydrophobic interactions (pH close to pI and high ionic strength) led to lower performance. However, under these conditions, as confirmed by zeta potential measurements, the adsorption of both target proteins and contaminant proteins is favored. Thus, low selectivity is achieved at all of the studied conditions. These results confirm the initial hypothesis that CGAs act as ion exchangers and that the selectivity of the process can be manipulated by changing main operating parameters such as type of surfactant, pH and ionic strength.


Assuntos
Fracionamento Químico/métodos , Misturas Complexas/isolamento & purificação , Ácido Dioctil Sulfossuccínico/química , Lactoferrina/isolamento & purificação , Lactoperoxidase/isolamento & purificação , Leite/enzimologia , Modelos Químicos , Animais , Ânions , Bovinos , Coloides/química , Coloides/isolamento & purificação , Técnicas de Química Combinatória , Misturas Complexas/química , Simulação por Computador , Ácido Dioctil Sulfossuccínico/isolamento & purificação , Gases/química , Gases/isolamento & purificação , Lactoferrina/química , Lactoperoxidase/química , Leite/química , Modelos Estatísticos , Tensoativos/química , Tensoativos/isolamento & purificação
11.
Atherosclerosis ; 157(1): 23-9, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11427200

RESUMO

We have used discoidal reconstituted high density lipoproteins (rHDL) containing apolipoprotein (apo) A-I and dimyristoyl phosphatidylcholine (DMPC) as a tool to investigate the time sequence of the HDL-mediated inhibition of vascular cell adhesion molecule (VCAM)-1 and E-selectin expression in cytokine-activated human umbilical vein endothelial cells (HUVECs). Specifically, we have asked a few questions - (i) how long do the cells need to be exposed to the rHDL before adhesion molecule expression is inhibited and (ii) how long does the inhibition persist after removing the rHDL from the cells. When the cells were not pre-incubated with the rHDL, there was no inhibition. The magnitude of the inhibition increased progressively with increasing duration of pre-incubation up to 16 h. Inhibition did not require the rHDL to be physically present during the activation of adhesion molecule expression by tumour necrosis factor(TNF)-alpha, excluding the possibility that the rHDL was merely interfering with the interaction between TNF-alpha and the cells. When HUVECs were pre-incubated for 16 h with rHDL, the inhibition remained substantial even if the rHDL were removed from the medium up to 8 h prior to addition of TNF-alpha. The HDL-mediated inhibition of VCAM-1 in HUVECs was unaffected by the presence of puromycin, an inhibitor of protein synthesis, excluding the possibility that HDL may have acted by stimulating the synthesis of a cell protein that itself inhibits adhesion molecule expression. These results have important implications in terms of understanding the mechanism(s) of the HDL-mediated inhibition of endothelial adhesion molecule expression.


Assuntos
Endotélio Vascular/metabolismo , Lipoproteínas HDL/farmacologia , Molécula 1 de Adesão de Célula Vascular/biossíntese , Células Cultivadas , Humanos , Lipoproteínas HDL/química , Fatores de Tempo
12.
Enzyme Microb Technol ; 28(6): 499-509, 2001 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-11267644

RESUMO

The individual effect of two different enzymes-protease and cellulase-on oil and protein extraction yields combined with other process parameters-enzyme concentration, time of hydrolysis, particle size and solid-to-liquid ratio-was evaluated by Response Surface Methodology. The selection of the enzymes for the study was based on preliminary experiments that showed higher increments in the extraction yield with the use of the two enzymes when compared to hemicellulase and pectinase. The levels of the quantitative parameters studied were: i) enzyme concentration: 0.1, 0.45, 2 w/w %; ii) liquid-to-solid ratio: 0.05, 0.125, 0.2; iii) mean particle size: 212.5, 449.5, 855 µm; iv) time of hydrolysis: 30; 60; 120 min. Experimental data for both oil and protein extraction yields obtained with and without enzymes correlated very well with process parameters (P < 0.0001), resulting in models with high coefficient of determination for oil and protein extraction yields (r(2) = 0.9570 and r(2) = 0.9807, respectively). The use of protease resulted in significantly higher yields over the control (protein yield increased from 27.8 to 66.2%, oil yield increased from 41.8 to 58.7%) only when heat treated flour was used, or when non-heat treated flour with large particle sizes was used in the extraction. The yields of protein and oil from non-heat treated material in general decreased slightly with the use of enzymes.

13.
Vaccine ; 18(17): 1743-54, 2000 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-10699322

RESUMO

Pneumococcal surface protein A (PspA) is a highly variable protein found on all strains of pneumococci. To be successful, a PspA-based vaccine for S. pneumoniae must induce antibodies that are broadly cross-reactive. To address whether cross-reactive antibodies could be induced in man, we evaluated serum from adults immunized with recombinant clade 2 PspA from strain Rx1. Immunization with 5-125 microg rPspA lead to a significant increase in circulating anti-PspA antibodies, as well as antibodies reactive to heterologous rPspA molecules. Increased binding of post-immune sera to 37 pneumococcal strains expressing a variety of PspA and capsule types was observed, versus pre-immune sera. The extent of cross-clade reactivity of human anti-rPspA followed roughly the amount of sequence homology to the non-clade 2 antigens. It is hypothesized that priming of humans by natural exposure to S. pneumoniae contributes to the breadth of the cross-reactivity of antibody to PspA.


Assuntos
Formação de Anticorpos/imunologia , Proteínas de Bactérias/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia , Adolescente , Adulto , Animais , Anticorpos Antibacterianos/sangue , Formação de Anticorpos/efeitos dos fármacos , Especificidade de Anticorpos , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/administração & dosagem , Proteínas de Bactérias/genética , Ligação Competitiva/imunologia , Reações Cruzadas/imunologia , Método Duplo-Cego , Humanos , Imunoglobulina G/sangue , Injeções Intramusculares , Pessoa de Meia-Idade , Coelhos , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/imunologia
14.
J Biol Chem ; 275(12): 9019-25, 2000 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-10722751

RESUMO

Previous studies have provided detailed information on the formation of spherical high density lipoproteins (HDL) containing apolipoprotein (apo) A-I but no apoA-II (A-I HDL) by an lecithin:cholesterol acyltransferase (LCAT)-mediated process. In this study we have investigated the formation of spherical HDL containing both apoA-I and apoA-II (A-I/A-II HDL). Incubations were carried out containing discoidal A-I reconstituted HDL (rHDL), discoidal A-II rHDL, and low density lipoproteins in the absence or presence of LCAT. After the incubation, the rHDL were reisolated and subjected to immunoaffinity chromatography to determine whether A-I/A-II rHDL were formed. In the absence of LCAT, the majority of the rHDL remained as either A-I rHDL or A-II rHDL, with only a small amount of A-I/A-II rHDL present. By contrast, when LCAT was present, a substantial proportion of the reisolated rHDL were A-I/A-II rHDL. The identity of the particles was confirmed using apoA-I rocket electrophoresis. The formation of the A-I/A-II rHDL was influenced by the relative concentrations of the precursor discoidal A-I and A-II rHDL. The A-I/A-II rHDL included several populations of HDL-sized particles; the predominant population having a Stokes' diameter of 9.9 nm. The particles were spherical in shape and had an electrophoretic mobility slightly slower than that of the alpha-migrating HDL in human plasma. The apoA-I:apoA-II molar ratio of the A-I/A-II rHDL was 0.7:1. Their major lipid constituents were phospholipids, unesterified cholesterol, and cholesteryl esters. The results presented are consistent with LCAT promoting fusion of the A-I rHDL and A-II rHDL to form spherical A-I/A-II rHDL. We suggest that this process may be an important source of A-I/A-II HDL in human plasma.


Assuntos
Apolipoproteína A-II/metabolismo , Apolipoproteína A-I/metabolismo , Lipoproteínas HDL/metabolismo , Lipoproteínas HDL/ultraestrutura , Fosfatidilcolina-Esterol O-Aciltransferase/metabolismo , Ésteres do Colesterol/metabolismo , Humanos , Modelos Biológicos
15.
Biochem J ; 337 ( Pt 3): 445-51, 1999 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-9895287

RESUMO

We have shown previously that apolipoprotein A (apoA)-I-containing high-density lipoprotein (HDL) particles are formed by the conjugation of lipid-free apoA-I with lipids derived from other lipoprotein fractions in a process dependent on non-esterified fatty acids, generated by the lipolysis of very-low-density lipoprotein (VLDL) or provided exogenously. In the present study, we show that this process is also able to generate HDL particles containing apoA-II (A-II HDL) and both apoA-I and apoA-II (A-I/A-II HDL). When lipid-free apoA-II was incubated with either VLDLs and lipoprotein lipase or LDLs and sodium oleate, a significant proportion of the apoA-II was recovered in the HDL density fraction. This was associated with the formation of several populations of HDL-sized particles with pre-beta2 electrophoretic mobility, which contained phospholipids and unesterified cholesterol as their main lipid constituents. When both lipid-free apoA-I and lipid-free apoA-II were incubated with LDL and sodium oleate, both apolipoproteins were recovered in HDLs that contained phospholipids and unesterified cholesterol as their main lipids. Two populations of particles had diameters of 7.4 and 10.8 nm and pre-beta2-migration; there was also a population of pre-beta1-migrating particles of diameter 4.7 nm. ApoA-I and apoA-II were both present in the larger HDLs, whereas only apoA-I was present in the smaller particles. Immunoaffinity chromatography on an anti-(apoA-I)-Sepharose column revealed that 10-20% of the apoA-II resided in particles that also contained apoA-I. The majority of the A-I/A-II HDL were present in a population of pre-beta2 particles of 10.8 nm diameter. These results in vitro illustrate a potential mechanism for the formation of HDLs containing both apoA-I and apoA-II.


Assuntos
Apolipoproteína A-II/química , Apolipoproteína A-I/química , Lipoproteínas HDL/síntese química , Cromatografia de Afinidade , Eletroforese em Gel de Ágar , Eletroforese em Gel Bidimensional , Eletroforese em Gel de Poliacrilamida , Lipoproteínas LDL/química , Lipoproteínas VLDL/química , Ácido Oleico/química , Tamanho da Partícula
16.
Psychopharmacology (Berl) ; 134(1): 38-45, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9399365

RESUMO

The effects of cocaine and quinpirole were studied in baboons to determine whether quinpirole, a relatively selective D2/D3 dopamine agonist, produced effects similar to those of cocaine on perceptual and motor processes. To measure perceptual and motor function, three baboons were trained to discriminate differences between a standard vowel and four other synthetic vowels: response accuracy as well as response latencies, or "reaction times", were measured following drug administrations. Cocaine reduced reaction times in two baboons, and did not affect reaction times in a third; on the other hand, quinpirole lengthened reaction times in a dose-dependent manner in all baboons. Cocaine and quinpirole also differed in the time course to produce the maximal reaction time effect following drug administration. Cocaine and quinpirole did not differ consistently in their perceptual effects, as indicated by similar changes in d', a signal-detection index of discriminability. These distinct profiles of effects for cocaine and quinpirole suggest differing neurochemical actions for these two drugs.


Assuntos
Cocaína/farmacologia , Agonistas de Dopamina/farmacologia , Inibidores da Captação de Dopamina/farmacologia , Percepção/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Quimpirol/farmacologia , Animais , Percepção Auditiva/efeitos dos fármacos , Relação Dose-Resposta a Droga , Masculino , Papio , Tempo de Reação/efeitos dos fármacos , Comportamento Verbal/efeitos dos fármacos
17.
Am J Physiol ; 273(1 Pt 2): R161-7, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9249545

RESUMO

The presence of brown adipose tissue (BAT) in marsupials is controversial because attempts to identify mitochondrial uncoupling protein (UCP) have been unsuccessful. Sminthopsis crassicaudata is a small nocturnal marsupial with an interscapular pad of adipose tissue. Electron microscopy revealed this tissue to have characteristics typical of BAT. GDP binding and UCP detection by immunoblot confirmed BAT. Expression of UCP was increased by cold exposure. When animals were placed from 28 to 15 degrees C, body temperature (Tb) decreased by 1.7 degrees C within 30 min and a further 1.0 degree C by 90 min (P < 0.001) before stabilizing at these lower levels. When animals were returned to 28 degrees C, Tb increased within 30 min (P < 0.001) and returned to basal by 120 min. When animals were maintained at 15 degrees C with ad libitum food for 12 days, Tb (P < 0.05), tail width (P < 0.04), and O2 consumption (P < 0.01) all decreased. The respiratory quotient increased (P < 0.001), indicating a change from fat to carbohydrate utilization. Food intake was unchanged, and body weight increased on day 1 (P < 0.01) before returning to baseline on day 3, remaining stable thereafter. These data suggest that although BAT is present in the marsupial S. crassicaudata, it may not be necessary for thermogenesis, at least in the short term. S. crassicaudata utilizes a plasticity in Tb and a change in substrate utilization to maintain energy balance and body composition without the need for an increase in metabolic rate or food consumption and without the need for torpor.


Assuntos
Tecido Adiposo Marrom/fisiologia , Regulação da Temperatura Corporal , Proteínas de Transporte/biossíntese , Metabolismo Energético , Marsupiais/fisiologia , Proteínas de Membrana/biossíntese , Aclimatação , Adipócitos/fisiologia , Adipócitos/ultraestrutura , Tecido Adiposo Marrom/ultraestrutura , Animais , Peso Corporal , Temperatura Baixa , Comportamento Alimentar , Guanosina Difosfato/metabolismo , Canais Iônicos , Masculino , Camundongos , Microscopia Eletrônica , Mitocôndrias/metabolismo , Proteínas Mitocondriais , Modelos Biológicos , Consumo de Oxigênio , Proteína Desacopladora 1
18.
Bioseparation ; 7(1): 31-7, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9615611

RESUMO

Transgenic sheep milk containing the protein human alpha 1-Antitrypsin (AAT) was partitioned in Poly(ethylene glycol) (PEG)-Sulphate and PEG-Phosphate biphasic systems. Individual partition coefficients for AAT and some of the milk proteins were determined in these systems. The effects of PEG molecular weight, pH and the inclusion of NaCl on the partitioning of the proteins were also studied. It was found that increasing the concentration of NaCl and decreasing the molecular weight of the PEG resulted in an increase of the partition coefficients of the proteins to the upper (PEG) phase. This partitioning effect was greater for the more hydrophobic proteins and particularly in systems having a pH close to the isoelectric point of the protein. Solubilities of the proteins in increasing concentrations of ammonium sulphate were measured in order to investigate the effects of hydrophobic and electrostatic interactions on the partitioning of these proteins in aqueous two-phase systems. Those proteins that precipitated at low levels of ammonium sulphate showed an increase in partition coefficient at low concentrations of NaCl, or they were precipitated at the interface of the phase at low concentrations of NaCl. Proteins that had low salting out constants in ammonium sulphate solutions were relatively unaffected by NaCl in ATPS. It is probable however that conformational changes and the state of aggregation of proteins are also important and should be invoked in describing the partitioning behavior observed for beta-Lg for example. Comparison of theoretical and experimental values for AAT yield and purity showed clearly that partition coefficients are influenced by the degree of purity and values obtained with purified standards are not necessarily the same as for the same protein present in a complex mixture. Under the most favourable conditions using a 4% w/w loading of transgenic ovine milk, we obtained a 91% yield of AAT in the PEG phase with a purity of 73%.


Assuntos
Leite/química , Proteínas Recombinantes/isolamento & purificação , Animais , Animais Geneticamente Modificados , Biotecnologia , Feminino , Humanos , Proteínas do Leite/isolamento & purificação , Peso Molecular , Polietilenoglicóis/química , Proteínas Recombinantes/genética , Ovinos , Cloreto de Sódio , Água , alfa 1-Antitripsina/genética , alfa 1-Antitripsina/isolamento & purificação
20.
Psychopharmacology (Berl) ; 125(2): 120-8, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8783385

RESUMO

The effects of cocaine on speech sound discriminations was examined to determine whether cocaine's previously demonstrated effect in reducing speech sound discriminability was dependent upon either the type of stimuli employed (simple tones versus complex speech) or the procedure (stimulus detection versus stimulus discrimination). Because of demonstrated similarities in the way that baboons and humans discriminate speech, and in the way the CNS is thought to encode and process speech sounds in these two species, baboons were trained to perform a choice procedure to identify the occurrence of different synthetic vowel sounds (see text). Animals held down a lever and released the lever only when one of four target vowels sounded, and not when a fifth, standard vowel sounded. Acute IM administration of cocaine (0.0032-1.0 mg/kg) produced dose-dependent decreases in vowel discriminability that were mostly due to elevations in false alarms (i.e., releases to the standard vowel) following cocaine. Cocaine also shortened reaction times to the stimuli in two of three baboons, but to a much lesser extent than observed previously. These results suggest that cocaine may interfere with the ability of the CNS to process the acoustic cues in speech sounds, and that the effects of cocaine on reaction times may depend upon the complexity of the reaction time procedure employed.


Assuntos
Percepção Auditiva/efeitos dos fármacos , Cocaína/farmacologia , Entorpecentes/farmacologia , Tempo de Reação/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Masculino , Papio , Fatores de Tempo
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