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1.
Vox Sang ; 112(3): 201-209, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28198026

RESUMO

BACKGROUND: Although most studies have shown that little haemolysis is induced by infusion pumps, there are some notable exceptions. Only limited data are available on the actual infusion pumps that are most used in hospitals in Quebec and elsewhere, namely, the Infusomat® Space (peristaltic), Plum A+™ (piston) and Colleague® CXE (shuttle) pumps. METHODS: Haemolysis and potassium levels were compared before and after the use of the three different infusion pumps. Using 135 units of packed red blood cells (RBCs) aged from 10 to 28 days, 27 measurements were taken for each pump at various flow rates (30, 60, 150, 300 and 450 ml/h) and were compared with measurements taken before using the pumps. The range of flow rates was chosen to cover those of paediatric and adult transfusions. RESULTS: The shuttle- and piston-type pumps resulted in low haemolysis levels. The peristaltic-type pump produced significantly more haemolysis, which worsened at low flow rates, but the absolute value of haemolysis remained within the range recommended by the regulatory agencies in North America and Europe. Approximately two-thirds of the haemolysis produced by the peristaltic-type pump seemed to be secondary to the use of an antisiphon valve (ASV) on the transfusion line recommended by the manufacturer. Potassium levels did not increase with the use of the pumps. CONCLUSION: Modern infusion pumps widely used in hospitals in Quebec and elsewhere produce non-threatening levels of haemolysis during the transfusion of packed RBCs aged from 10 to 28 days. ASVs appear to induce additional haemolysis, and we do not recommend using them for blood transfusion.


Assuntos
Transfusão de Eritrócitos/instrumentação , Bombas de Infusão , Transfusão de Eritrócitos/métodos , Eritrócitos/citologia , Eritrócitos/metabolismo , Hematócrito , Hemoglobinas/análise , Hemólise , Humanos , Potássio/análise , Resistência ao Cisalhamento , Fatores de Tempo
2.
Vox Sang ; 110(2): 150-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26389829

RESUMO

BACKGROUND AND OBJECTIVES: Platelet concentrates (PCs) are associated with transfusion reactions involving hypotension, particularly bradykinin-mediated acute hypotensive transfusion reactions. This study aims to determine the incidence of hypotensive events and more specifically acute hypotensive transfusion reaction associated with PC transfusions. We also sought to ascertain whether these reactions are associated with elevated bradykinin levels. MATERIALS AND METHODS: This is a prospective descriptive study of PCs administered at Sainte-Justine Hospital over 28 months. All PCs administered during this period were screened for hypotension through review of all transfusion-associated reaction reports (TARRs) sent to the blood bank. All residual PC bags were returned to the blood bank. TARRs associated with hypotension were reviewed by adjudicators that established the imputability of the PC transfusion to the reaction. Bradykinin levels were sampled in the first 168 PC bags returned to the blood bank. Levels were compared between PCs associated with hypotension and control PCs not associated with hypotension. RESULTS: A total of 3672 PC bags were returned to the blood bank; 25 PCs were associated with hypotension. Adjudicators ascertained that five hypotensive events were imputable to PCs of which one was an acute hypotensive transfusion reaction (incidence: 0·03%). Bradykinin level in the latter PC was 10 pg/ml, whereas levels were 226·2 ± 1252 pg/ml in the 143 control PCs. CONCLUSION: Our results show a low incidence of hypotension after PC transfusion. We identified only one acute hypotensive transfusion reaction. No correlation between bradykinin level and the occurrence of acute hypotensive reactions could be observed given that only one event was identified.


Assuntos
Hipotensão/etiologia , Transfusão de Plaquetas/efeitos adversos , Reação Transfusional/etiologia , Bancos de Sangue/normas , Humanos
3.
Vox Sang ; 111(4): 341-349, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27280338

RESUMO

BACKGROUND AND OBJECTIVES: Fluid warmers are routinely used to reduce the risk of hypothermia and cardiac complications associated with the infusion of cold blood products. However, warming blood products could generate haemolysis. This study was undertaken to compare the impact of temperature of blood warmers on the per cent haemolysis of packed red blood cells (RBCs) heated at different flow rates as well as non-flow conditions. MATERIALS AND METHODS: Infusion warmers used were calibrated at 41·5°C ± 0·5°C and 37·5°C ± 0·5°C. Cold RBC units stored at 4°C in AS-3 (n = 30), aged 30-39 days old, were divided into half units before being allocated under two different scenarios (i.e. infusion pump or syringe). RESULTS: Blood warmers were effective to warm cold RBCs to 37·5°C or 41·5°C when used in conjunction with an infusion pump at flow rate up to 600 ml/h. However, when the warmed blood was held in a syringe for various periods of time, such as may occur in neonatal transfusions, the final temperature was below the expected requirements with measurement as low as 33·1°C. Increasing the flow with an infusion pump increased haemolysis in RBCs from 0·2% to up to 2·1% at a flow rate of 600 ml/h regardless of the warming device used (P < 0·05). No relevant increase of haemolysis was observed using a syringe. CONCLUSIONS: The use of a blood warmer adjusted to 41·5°C is probably the best choice for reducing the risk of hypothermia for the patient without generating haemolysis. However, we should be cautious with the use of an infusion pump for RBC transfusion, particularly at high flow rates.


Assuntos
Transfusão de Sangue/métodos , Eritrócitos/fisiologia , Hemólise , Segurança do Sangue , Sobrevivência Celular , Contagem de Eritrócitos , Humanos , Temperatura
4.
Vox Sang ; 106(2): 127-36, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24024981

RESUMO

BACKGROUND AND OBJECTIVES: Many countries allow the overnight storage of whole blood (WB) at ambient temperature. Some countries, such as Canada, also require a rapid cooling of WB with an active cooling system. Given the significant operational constraints associated with current cooling systems, an alternative method for cooling and transporting WB at 20-24°C was evaluated. MATERIALS AND METHODS: Phase 22 cooling packs (TCP Reliable Inc., USA) were used in combination with vacuum-insulated panel (VIP) boxes. Temperature profiles of simulated WB units were studied in extreme temperatures (-35 and 40°C). The quality of blood components prepared using Phase 22 packs and CompoCool-WB (Fresenius HemoCare, Germany) was studied. RESULTS: Phase 22 packs reduced the temperature of simulated WB bags from 37 to 24°C in 1·7 ± 0·2 h. Used in combination with VIP boxes, Phase 22 packs maintain the temperature of bags between 20 and 24°C for 15 and 24 h, compared to 2 and 11 h with CompoCool-WB, when exposed at -35 and 40°C, respectively. The quality of platelet concentrates and plasma was comparable, regardless of the cooling system used. For red blood cell units, per cent haemolysis on day 42 was slightly higher in products prepared after cooling with Phase 22 packs compared to CompoCool-WB (0·33 ± 0·15% vs. 0·21 ± 0·06%; P < 0·05). CONCLUSIONS: Phase 22 packs combined with VIP boxes are an acceptable alternative to butane-1,4-diol cooling systems. This system allows blood manufacturers to transport WB to processing facilities in a broad range of environmental conditions.


Assuntos
Preservação de Sangue/métodos , Temperatura Baixa , Congelamento , Temperatura Alta , Humanos , Temperatura
5.
Vox Sang ; 107(3): 239-46, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24730703

RESUMO

BACKGROUND AND OBJECTIVES: Many international standards state that red blood cell (RBC) products should be discarded if left out of controlled temperature storage for longer than 30 min to reduce the risk of bacterial growth and RBC loss of viability. This study aimed to verify whether repeated short-time exposures to room temperature (RT) influence RBCs quality and bacterial proliferation. MATERIALS AND METHODS: Saline-adenine-glucose-mannitol (SAGM) and AS-3 RBC units were split and exposed to RT for 30 or 60 min on day 2, 7, 14, 21, and 42 of storage while reference units remained stored at 1-6°C. Red blood cell in vitro quality parameters were evaluated after each exposure. In a second experiment, SAGM and AS-3 RBC units were split and inoculated with Staphylococcus epidermidis (5 CFU/ml), Serratia marcescens (1 CFU/ml), and Serratia liquefaciens (1 CFU/ml). Reference units remained in storage while test units were exposed as described previously. Bacterial concentrations were investigated after each exposure. RESULTS: No differences were noticed between reference and test units in any of the in vitro parameters investigated. S. epidermidis did not grow in either reference or exposed RBCs. While S. marcescens did not grow in AS-3, bacterial growth was observed in RT-exposed SAGM RBCs on day 42. Similar growth was obtained for S. liquefaciens in the two additive solutions for both reference and test units. CONCLUSION: Short-time exposures to RT do not affect RBC quality and do not significantly influence bacterial growth. An expansion of the '30-minute' rule to 60 min should be considered by regulatory agencies.


Assuntos
Preservação de Sangue/normas , Eritrócitos/microbiologia , Temperatura , Doadores de Sangue , Preservação de Sangue/efeitos adversos , Criopreservação , Humanos , Manitol , Segurança , Serratia liquefaciens/crescimento & desenvolvimento , Serratia marcescens/crescimento & desenvolvimento , Cloreto de Sódio , Soluções , Staphylococcus epidermidis/crescimento & desenvolvimento
6.
Med Trop (Mars) ; 72 Spec No: 19-22, 2012 Mar.
Artigo em Francês | MEDLINE | ID: mdl-22693921

RESUMO

The epidemic of chikungunya (CHIK) that swept through Reunion Island from late 2005 to mid 2006 affected 38.2% of the population, i.e., 300000 people. Although this outbreak took place in a French overseas department with high public health standards, failure to anticipate a large-scale epidemic associated with unprecedented severity and unexpectedly high mortality led to a major public health crisis. The purpose of this report is to provide a complete account of the experience of hospital intensive care physicians in addressing problems ranging from discovery of severe forms to management of a major health crisis. This report underlines the role of the head hospital physician and the necessity of mutual trust and collaboration with supervisory authorities.


Assuntos
Infecções por Alphavirus/epidemiologia , Infecções por Alphavirus/prevenção & controle , Surtos de Doenças , Papel do Médico , Serviços Preventivos de Saúde/organização & administração , Infecções por Alphavirus/mortalidade , Atitude do Pessoal de Saúde , Febre de Chikungunya , Comportamento Cooperativo , Surtos de Doenças/prevenção & controle , Epidemias , Hospitais/estatística & dados numéricos , Humanos , Reunião/epidemiologia , Fatores de Tempo , Recursos Humanos
7.
Vox Sang ; 99(2): 136-41, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20345516

RESUMO

BACKGROUND AND OBJECTIVES: IgA deficiency is common (1/500) and up to 40% of affected individuals will develop anti-IgA. A few studies suggested that passive transfusion of anti-IgA was not associated with an increased risk of allergic reactions. This study was designed to assess the safety of transfusing blood components containing anti-IgA. MATERIALS AND METHODS: IgA-deficient blood donors with and without anti-IgA were identified from Héma-Québec's (HQ) computerized database. IgA deficiency was confirmed by an ELISA method and the presence of anti-IgA by a passive hemagglutination assay. Blood donations from IgA-deficient donors issued to hospitals between March 1999 and December 2004 were retrieved. Medical charts of recipients were reviewed for the occurrence of a suspected transfusion reaction. Presence and nature of transfusion reactions were assessed blindly by an adjudicating committee. RESULTS: A total of 323 IgA-deficient blood products were issued by HQ to 55 hospitals. Of these, 48 agreed to participate [315 blood products (97.5%)]. A total of 272 products were transfused: 174 contained anti-IgA, and 98 did not. Only two minor allergic reactions occurred in each group. Incidence of allergic reactions was 1.15% in the anti-IgA group and 2.04% in the group without anti-IgA (P = 0.91). There was no anaphylactic reaction in either group. CONCLUSIONS: This study indicates that the proportion of allergic reactions does not appear to be greater in recipients of blood components containing anti-IgA compared to recipients of non-anti-IgA-containing components. Allowing donations from IgA-deficient donors with anti-IgA may therefore be contemplated.


Assuntos
Anticorpos Anti-Idiotípicos/sangue , Hipersensibilidade/sangue , Deficiência de IgA/sangue , Transfusão de Plaquetas/efeitos adversos , Reação Transfusional , Anticorpos Anti-Idiotípicos/imunologia , Feminino , Humanos , Hipersensibilidade/etiologia , Hipersensibilidade/imunologia , Deficiência de IgA/imunologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Doadores de Tecidos
8.
AJNR Am J Neuroradiol ; 41(10): 1856-1862, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32943417

RESUMO

BACKGROUND AND PURPOSE: There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies. MATERIALS AND METHODS: The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society. RESULTS: Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure. CONCLUSIONS: More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor.


Assuntos
Aneurisma Roto/terapia , Procedimentos Endovasculares , Aneurisma Intracraniano/terapia , Trombose Intracraniana/prevenção & controle , Inibidores da Agregação Plaquetária/uso terapêutico , Adulto , Consenso , Técnica Delphi , Embolização Terapêutica/efeitos adversos , Embolização Terapêutica/instrumentação , Embolização Terapêutica/métodos , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/instrumentação , Procedimentos Endovasculares/métodos , Feminino , Humanos , Trombose Intracraniana/etiologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Stents
9.
AJNR Am J Neuroradiol ; 41(12): 2274-2279, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33122218

RESUMO

BACKGROUND AND PURPOSE: There are only few data and lack of consensus regarding antiplatelet management for carotid stent placement in the setting of endovascular stroke treatment. We aimed to develop a consensus-based algorithm for antiplatelet management in acute ischemic stroke patients undergoing endovascular treatment and simultaneous emergent carotid stent placement. MATERIALS AND METHODS: We performed a literature search and a modified Delphi approach used Web-based questionnaires that were sent in several iterations to an international multidisciplinary panel of 19 neurointerventionalists from 7 countries. The first round included open-ended questions and formed the basis for subsequent rounds, in which closed-ended questions were used. Participants continuously received feedback on the results from previous rounds. Consensus was defined as agreement of ≥70% for binary questions and agreement of ≥50% for questions with >2 answer options. The results of the Delphi process were then summarized in a draft manuscript that was circulated among the panel members for feedback. RESULTS: A total of 5 Delphi rounds were performed. Panel members preferred a single intravenous aspirin bolus or, in jurisdictions in which intravenous aspirin is not available, a glycoprotein IIb/IIIa receptor inhibitor as intraprocedural antiplatelet regimen and a combination therapy of oral aspirin and a P2Y12 inhibitor in the postprocedural period. There was no consensus on the role of platelet function testing in the postprocedural period. CONCLUSIONS: More and better data on antiplatelet management for carotid stent placement in the setting of endovascular treatment are urgently needed. Panel members preferred intravenous aspirin or, alternatively, a glycoprotein IIb/IIIa receptor inhibitor as an intraprocedural antiplatelet agent, followed by a dual oral regimen of aspirin and a P2Y12 inhibitor in the postprocedural period.


Assuntos
Hemorragia Cerebral/prevenção & controle , AVC Isquêmico/terapia , Inibidores da Agregação Plaquetária/uso terapêutico , Stents , Acidente Vascular Cerebral/cirurgia , Consenso , Técnica Delphi , Procedimentos Endovasculares/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Trombectomia/métodos
11.
Vox Sang ; 94(4): 286-91, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18208406

RESUMO

BACKGROUND AND OBJECTIVES: A previous study indicated that the extension of whole blood (WB) storage from 8 to 24 h at 20-24 degrees C before the processing of platelet-rich plasma (PRP)-depleted red blood cell (RBC) units had a negative effect on the efficacy of leucoreduction filters. In this study, we further characterized the phenomenon and tested the leucoreduction capacity of two newly developed filters. MATERIALS AND METHODS: Whole blood was stored at 20-24 degrees C and processed at 4-h intervals between 8 and 24 h postcollection. Components were leucoreduced before storage. Efficacy of novel filters to leucoreduce 24-h-hold PRP-depleted RBC units was also evaluated. RESULTS: Using a conventional filter, the mean residual white blood cell (WBC) counts in leucoreduced PRP-depleted RBCs were comparable in units prepared within 12 h from collection but gradually increased upon extended preprocessing storage from 0.36 +/- 0.03 at 12 h to 0.46 +/- 0.21, 0.76 +/- 0.54 and 1.72 +/- 1.76 x 10(6) per unit at 16, 20 and 24 h, respectively. However, the mean residual WBC content in 24-h-hold RBCs was reduced to 0.60 +/- 0.39 x 10(6) and 0.46 +/- 0.13 x 10(6) per units using RC2D and the prototypes B-1582 rev B filters, respectively. CONCLUSION: For PRP-depleted RBC units, the extension of the WB room temperature storage from 8 to 24 h before processing is likely to require the introduction of newly developed filters having an increased leucoreduction capacity in order to meet the maximal residual WBC guideline in the RBCs.


Assuntos
Filtração/instrumentação , Procedimentos de Redução de Leucócitos/instrumentação , Procedimentos de Redução de Leucócitos/métodos , Canadá , Transfusão de Eritrócitos , Humanos , Plasma Rico em Plaquetas/citologia , Manejo de Espécimes , Temperatura
12.
Physiol Behav ; 90(5): 760-70, 2007 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-17336348

RESUMO

Aminoglycosides (AG) such as gentamicin are antimicrobial drugs widely used in the hospital setting due to their efficacy in the treatment of severe gram-negative bacterial infections. However, all AG have the potential to cause nephrotoxicity. Two studies have been conducted (1) to assess the protein level of a diet that would give the best renal outcome with gentamicin administration, and (2) to get a better idea about the rhythms of food ingestion associated with the different protein levels. Adult female Sprague-Dawley rats fully adapted to a standard chow diet, the standard chow with 20% or 55% added casein were chronically treated for 10 days with a nephrotoxic dose of gentamicin sulfate (40 mg/kg/day, i.p.) or a saline solution. Food ingestion patterns of rats were recorded every hour using a Diet Scan system and gentamicin nephrotoxicity indices were measured. The second study used rats that were fed the same diets and given a sham injection. Corticosterone was assayed to quantify the stress of the animals. Results showed that chronic gentamicin treatment leads to a decrease in food intake and flattening of the rhythms of food ingestion. Also, chow feeding and the 20% casein diet were found to be more protective against gentamicin-induced nephrotoxicity than the 55% casein diet. Therefore, while a protein-rich diet can be protective against gentamicin-induced nephrotoxicity, the present study demonstrates that a diet too high in protein might rather be harmful to the kidneys.


Assuntos
Antibacterianos/toxicidade , Proteínas Alimentares/metabolismo , Comportamento Alimentar/efeitos dos fármacos , Gentamicinas/toxicidade , Nefropatias/induzido quimicamente , Animais , Caseínas/metabolismo , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/fisiologia , Corticosterona/sangue , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Comportamento Alimentar/fisiologia , Feminino , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/fisiopatologia , Nefropatias/prevenção & controle , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley
13.
Biochim Biophys Acta ; 1049(1): 45-58, 1990 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-2113406

RESUMO

Poly(ADP-ribose) is synthesized and degraded by poly(ADP-ribose) polymerase and glycohydrolase, respectively. We have reconstituted in vitro two turnover systems containing these two enzymes. We have measured the kinetics of NAD consumption and polymer accumulation during turnover. The combined action of the two enzymes (i.e., turnover) generates a steady state of polymer quantity. The glycohydrolase determines the time and the level at which this steady state of total polymer is reached. A major observation is that the size and calculated density of polymer bound to the total polymerase molecules is tightly regulated by the rate of polymer turnover. On the polymerase, an increase in the rate of polymer turnover does not affect the mean polymer size, but reduces the polymer density on the enzyme (i.e., the number of polymer chains per polymerase molecule). In the absence of glycohydrolase and at low histone H1 concentration (less than 1.5 micrograms/ml), poly(ADP-ribose) polymerase preferentially automodifies itself instead of modifying histone H1. In contrast, under turnover conditions, oligomer accumulation on histone H1 was greatly increased, with almost 40% of all the polymer present on H1 after 5 min of turnover. Although turnover conditions were necessary for histone H1 labelling, there was no difference between the fast and the slow turnover systems as concerns the proportion of histone H1 labelling, although the mean polymer size on histone H1 was decreased with increasing turnover rate. Due to its small size, polymer is not degraded by the glycohydrolase and accumulates on histone H1 during turnover. These data suggest that the glycohydrolase modulates the level of poly(ADP-ribosyl)action of different proteins in two ways; by degrading shorter polymers at a slower rate and probably by competing with the polymerase for polymer.


Assuntos
Poli(ADP-Ribose) Polimerases/metabolismo , Timo/metabolismo , Animais , Ligação Competitiva , Bovinos , Histonas/farmacologia , Hidrolases/farmacologia , Hidrólise , Técnicas In Vitro , Cinética , Peso Molecular , NAD/metabolismo , Timo/efeitos dos fármacos
14.
Artigo em Inglês | MEDLINE | ID: mdl-26382508

RESUMO

In this article, we show that the projection-free, snapshot-based, balanced truncation method can be applied directly to unstable systems. We prove that even for unstable systems, the unmodified balanced proper orthogonal decomposition algorithm theoretically yields a converged transformation that balances the Gramians (including the unstable subspace). We then apply the method to a spatially developing unstable system and show that it results in reduced-order models of similar quality to the ones obtained with existing methods. Due to the unbounded growth of unstable modes, a practical restriction on the final impulse response simulation time appears, which can be adjusted depending on the desired order of the reduced-order model. Recommendations are given to further reduce the cost of the method if the system is large and to improve the performance of the method if it does not yield acceptable results in its unmodified form. Finally, the method is applied to the linearized flow around a cylinder at Re = 100 to show that it actually is able to accurately reproduce impulse responses for more realistic unstable large-scale systems in practice. The well-established approximate balanced truncation numerical framework therefore can be safely applied to unstable systems without any modifications. Additionally, balanced reduced-order models can readily be obtained even for large systems, where the computational cost of existing methods is prohibitive.

15.
Neurosci Biobehav Rev ; 23(4): 457-528, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10073890

RESUMO

The only evidence for nutrient selection comes from baseline or treatment effects on nutrient intakes that are qualitatively similar when sensorily contrasting forms of each macronutrient are investigated and/or dietary compositions and strains of rat or mouse are different within or between laboratories. By that criterion the only potential case of a treatment reliably altering macronutrient selection identified in the present review of the literature is d-norfenfluramine, fluoxetine and paraventricular serotonin (5-HT) reducing the intake of dextrin-containing diets at early dark. The only clear example of reverse effects of an agonist and an antagonist on dietary intake was found with serotonergic agents. Claims for catecholaminergic or opioid involvement in protein intake and peptidergic involvement in carbohydrate intake were not substantiated. There remain the issues of which learnt macronutrient-specific postgastric actions and sensory cues from the affected diet rely on the neural pathway(s) on which the drug is acting to alter dietary selection. Until experiments address these questions, the neural bases of nutrient-specific appetites will remain unknown. Drug effects must be consistent across differently textured and flavoured versions of each macronutrient tested.


Assuntos
Preferências Alimentares/fisiologia , Preferências Alimentares/psicologia , Fenômenos Fisiológicos do Sistema Nervoso , Roedores/fisiologia , Animais , Ingestão de Alimentos/fisiologia , Camundongos , Estado Nutricional , Ratos
16.
FEBS Lett ; 393(2-3): 253-8, 1996 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-8814300

RESUMO

We investigated insulin's effect on intestinal lipid, transport and, particularly, the biogenesis of apolipoproteins crucial to lipoprotein secretion. Adding insulin (3 mU) to the serum-free medium of cultured jejunal explants from human fetuses (17-20 weeks) reduced triglyceride and chylomicron production and inhibited apo B-48 and apo B-100 secretion. When apo B mRNA was assayed by RT-PCR and its editing by primer extension, no change was detectable following the addition of insulin. HDL lipid content, apo A-1 synthesis and RNA level were unaffected by insulin. Collectively, these results suggest that the insulin-stimulated decline in intestinal chylomicron output may involve apo B co- or post-translational modifications.


Assuntos
Apolipoproteínas B/biossíntese , Expressão Gênica , Insulina/farmacologia , Jejuno/metabolismo , Edição de RNA , Aborto Induzido , Apolipoproteína A-I/biossíntese , Apolipoproteína B-100 , Apolipoproteína B-48 , Primers do DNA , Embrião de Mamíferos , Feminino , Feto , Idade Gestacional , Humanos , Jejuno/efeitos dos fármacos , Jejuno/embriologia , Metabolismo dos Lipídeos , Lipoproteínas/biossíntese , Técnicas de Cultura de Órgãos , Reação em Cadeia da Polimerase , Gravidez
17.
Free Radic Biol Med ; 28(1): 46-54, 2000 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-10656290

RESUMO

Mammalian sterol regulatory enzymes are integral membrane proteins of the endoplasmic reticulum. They play a critical role in liver cholesterol homeostasis and the maintenance of overall cholesterol balance in different species. Because lipid peroxidation has been implicated in hepatic dysfunction and atherosclerosis, we hypothesized that its occurrence could alter the composition and properties of the bilayer lipid environment, and thereby affect the functions of these membrane proteins. Preincubation of rat liver microsomes with iron (Fe)/ascorbate (50 microM/200 microM), known to induce peroxidation, resulted in a significant inhibition of (i) the rate-limiting enzyme in cholesterol biosynthesis, HMG-CoA reductase (46%, p < .01), (ii) the crucial enzyme controlling the conversion of cholesterol in bile acids, cholesterol 7alpha-hydroxylase (48%, p < .001), and (iii) the central enzyme for cholesterol esterification: Acyl-CoA:cholesterol acyltransferase (ACAT, 80%, p < .0001). The disturbances of these key enzymes took place concomitantly with the high production of malondialdehyde (350%, p < .007) and the loss of polyunsaturated fatty acids (36.19 +/- 1.06% vs. 44.24 +/- 0.41 in controls, p < .0008). While alpha-tocopherol simultaneously neutralized lipid peroxidation, preserved microsomal fatty acid status, and restored ACAT activity, it was not effective in preventing Fe/ascorbate-induced inactivation of both HMG-CoA reductase (44%, p < .01) and cholesterol 7alpha-hydroxylase (71%, p < .0001). These results indicate that Fe/ascorbate alters the activity of the rate-determining steps in liver cholesterol metabolism, either directly or via lipid peroxidation, capable of modifying their membrane environment. The present data also suggest that the three regulatory enzymes respond differently when exposed to Fe/ascorbate or antioxidants, which may be due to dissimilar mechanisms.


Assuntos
Ácido Ascórbico/farmacologia , Colesterol 7-alfa-Hidroxilase/metabolismo , Colesterol/metabolismo , Retículo Endoplasmático/enzimologia , Hidroximetilglutaril-CoA Redutases/metabolismo , Ferro/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Microssomos Hepáticos/efeitos dos fármacos , Oxidantes/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Esterol O-Aciltransferase/metabolismo , Animais , Ácidos e Sais Biliares/biossíntese , Catalase/farmacologia , Ácidos Graxos/metabolismo , Glutationa/farmacologia , Masculino , Malondialdeído/metabolismo , Lipídeos de Membrana/metabolismo , Microssomos Hepáticos/metabolismo , Estresse Oxidativo , Ratos , Vitamina E/farmacologia
18.
Am J Clin Nutr ; 57(4): 573-9, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8460614

RESUMO

The purpose of this study was to elucidate the roles of lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) in the lipoprotein derangement of cystic fibrosis (CF) patients with respect to their essential fatty acid (EFA) status. Triglyceride enrichment and cholesteryl ester (CE) depletion were observed in the lipoproteins of 22 CF patients. The abnormal chemical composition was more severe in 12 EFA-deficient (EFAD) than in 10 EFA-sufficient (EFAS) patients. Expressed in nmol.L-1.h-1, LCAT activity was higher (P < 0.05) in both EFAS (mean +/- SE, 92.7 +/- 1.9) and EFAD (108.8 +/- 3.0) patients than in control subjects (65.2 +/- 0.9). An equal CE transfer was recorded in the lipoprotein-deficient serum, as a source of CETP activity, in all groups studied by using normal exogenous low-density lipoprotein (LDL) and high-density lipoprotein (HDL). However, in contrast to the maximal amount of CE transferred from endogenous HDL to endogenous apolipoprotein B (apo B) in control subjects, a reduction in CETP activity was seen in CF patients and more pronounced in the EFAD group. These findings indicate that impaired lipoprotein composition may have marked effects on the transfer of CE between HDL and apo B in EFAD CF patients.


Assuntos
Proteínas de Transporte/fisiologia , Fibrose Cística/metabolismo , Ácidos Graxos Essenciais/deficiência , Glicoproteínas , Fosfatidilcolina-Esterol O-Aciltransferase/fisiologia , Adolescente , Apolipoproteínas/sangue , Criança , Proteínas de Transferência de Ésteres de Colesterol , Humanos , Lipídeos/sangue , Lipoproteínas/sangue
19.
Am J Clin Nutr ; 71(3): 807-15, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10702177

RESUMO

BACKGROUND: Growing evidence supports a role for peroxidation in the pathogenesis of Crohn disease (CD). The activation of inflammatory cells, the release of their mediators, and the excessive production of free radicals may affect circulating lipids. OBJECTIVE: We examined the lipid profile, lipoprotein composition, and oxidant-antioxidant status of children with CD. DESIGN: We studied 22 pediatric CD patients and 10 healthy control subjects. RESULTS: The proportion of saturated and monounsaturated fatty acids in plasma of CD patients was higher but that of polyunsaturated fatty acids was lower than in control subjects. This resulted in higher ratios in CD patients of palmitoleic acid to linoleic acid (P < 0. 05) and of eicosatrienoic acid to arachidonic acid (P < 0.04), 2 established indexes of essential fatty acid deficiency. Hypocholesterolemia was noted in CD patients as a result of lower LDL-cholesterol concentrations than in control subjects (P < 0.02). Plasma apolipoproteins B (P < 0.02) and A-I (P < 0.02) were also lower in CD patients, whereas plasma triacylglycerols were higher (P < 0.005). Lipoprotein composition was altered in CD patients, with relative triacylglycerol depletion and protein enrichment in VLDL. In contrast, intermediate-density lipoprotein of CD patients was characterized by an increased percentage of triacylglycerol and protein (P < 0.005) and a reduced proportion of phospholipids (P < 0. 01). Additional abnormalities were observed in the chemical distribution of HDL(2) and HDL(3) moieties. Lipid peroxidation was documented by higher plasma malondialdehyde concentrations in CD patients (P < 0.05), accompanied by lower retinol concentrations (P < 0.02). CONCLUSION: Disturbances in the lipid profile, in lipoprotein concentrations and composition, and in oxidant-antioxidant status occur in CD patients.


Assuntos
Antioxidantes/análise , Doença de Crohn/sangue , Lipídeos/sangue , Lipoproteínas/sangue , Adolescente , Apolipoproteína A-I/análise , Apolipoproteínas B/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Ácidos Graxos/sangue , Ácidos Graxos Insaturados/sangue , Feminino , Humanos , Masculino , Malondialdeído/sangue , Estado Nutricional , Estresse Oxidativo
20.
Am J Clin Nutr ; 57(6): 922-9, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8503363

RESUMO

Glycogen storage disease type I (GSD-I) is frequently complicated by severe hyperlipoproteinemia and the increased potential risk of premature atherosclerosis. The effects of fish-oil supplementation [MaxEPA, 10 g.(1.73 m2)-1 for 3 mo] were investigated prospectively in seven hyperlipoproteinemic patients with GSD-I. Hypertriglyceridemia and hypercholesterolemia improved after 3 mo of fish-oil treatment, decreasing 49% (P < 0.005) and 23%, respectively. This was accompanied by a reduction in both low-density-lipoprotein (LDL) cholesterol (25%, P < 0.03) and apolipoprotein B (40%) and by increased high-density-lipoprotein increased (HDL) cholesterol (30%, P < 0.002) and apolipoprotein A-I (31%, P < 0.05). Low pretreatment ratios of HDL to total cholesterol and HDL to LDL, indicators of elevated atherosclerosis risk, increased significantly (P < 0.05). Plasma lipoprotein profile as well as lipoprotein composition [triglyceride (TG) enrichment and cholesteryl depletion] improved. Reduced TG concentrations were due to enhanced fat catabolism, as evidenced by the significantly increased hepatic and extrahepatic lipoprotein lipase activity (P < 0.05). Withdrawal of fish oil for 3 mo was associated with a return to pretreatment abnormalities in plasma lipids and lipoproteins. Fish-oil supplementation thus improves the hyperlipoproteinemia in GSD-I and may significantly reduce the risk of premature atherosclerotic cardiovascular disease.


Assuntos
Óleos de Peixe/farmacologia , Doença de Depósito de Glicogênio Tipo I/sangue , Lipídeos/sangue , Lipase Lipoproteica/sangue , Lipoproteínas/sangue , Adolescente , Adulto , Colesterol/sangue , Colesterol/classificação , Óleos de Peixe/efeitos adversos , Doença de Depósito de Glicogênio Tipo I/complicações , Humanos , Hiperlipidemias/sangue , Hiperlipidemias/complicações , Masculino , Estudos Prospectivos
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