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1.
Med Mal Infect ; 45(7): 286-92, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26123765

ABSTRACT

OBJECTIVES: The aim of this study was to evaluate the proportion of transfer letters that contained information relative to infection or colonization by multidrug-resistant (MDR) bacteria and factors associated with the presence of that information. PATIENTS AND METHODS: Patients for whom at least one of these selected MDR bacteria (methicillin-resistant Staphylococcus aureus, extended-spectrum ß-lactamase-producing Enterobacteriaceae, or MDR Pseudomonas aeruginosa) was isolated during their hospitalization and who were transferred to another health care facility between 2009 and 2012 were included. Information of the MDR bacterium and the mention of isolation precautions were evaluated in the electronic medical record. RESULTS: Information (mention of MDR bacterium or isolation precaution) was present in 57% [52; 65] of records. Full information (genus and species, concept of MDR bacterium and mention of isolation precaution) was found in 20% [16; 25]. The presence of a dedicated item in the standard medical discharge letter was associated with more frequent information. Less information was retrieved with P. aeruginosa cases than with the other 2 MDR bacteria. CONCLUSION: The presence of the information has improved, but it is still insufficiently reported. Measures to improve information are needed. Indeed, information on MDR bacterial colonization or infection is the first step for isolation precautions. An item could be added to all standard medical discharge letters. An item could also be added to the indicators used to assess quality and safety in healthcare facilities.


Subject(s)
Drug Resistance, Multiple, Bacterial , Enterobacteriaceae Infections , Enterobacteriaceae , Infection Control , Medical Records , Methicillin-Resistant Staphylococcus aureus , Patient Transfer , Pseudomonas Infections , Pseudomonas aeruginosa , Staphylococcal Infections , Enterobacteriaceae/isolation & purification , Humans , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Patient Discharge , Pseudomonas aeruginosa/isolation & purification , Retrospective Studies
2.
Med Mal Infect ; 44(9): 412-6, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25193630

ABSTRACT

OBJECTIVE: Our objective was to estimate the case fatality rates of Zaire, Sudan, and Bundibugyo Ebola species, responsible for sometimes-lethal hemorrhagic fevers. METHODS: We performed a meta-analysis of World Health Organization data on outbreaks of infections due to theses species. RESULTS: Twenty outbreaks, including the current one, were studied. The estimated case fatality rate was 65.4% (CI 95% [54.6%; 75.5%]) and varied among the outbreaks. A species effect was identified, with a higher case fatality rate for the Zaire species than for Sudan and Bundibugyo species. The case fatality rate of the Zaire species tended to decrease with time. CONCLUSION: The case fatality rates associated with these 3 species was high. A great variability was observed. It could be explained partly by a species effect and by the decrease of Zaire species case fatality rate, with time.


Subject(s)
Disease Outbreaks/statistics & numerical data , Ebolavirus/classification , Hemorrhagic Fever, Ebola/mortality , Hemorrhagic Fever, Ebola/virology , Africa/epidemiology , Hemorrhagic Fever, Ebola/epidemiology , Humans , Regression Analysis , World Health Organization
3.
Nitric Oxide ; 23(3): 194-8, 2010 Nov 01.
Article in English | MEDLINE | ID: mdl-20547233

ABSTRACT

An overwhelming nitric oxide (NO) production is a crucial step in the circulatory events as well as in the cellular alterations taking place in septic shock. However, evidences of this role arise from studies assessing the NO production on an intermittent basis precluding any clear evaluation of temporal relationship between NO production and circulatory alterations. We evaluated this relationship by using a NO specific electrode allowing a continuous measurement of NO production. Septic shock was induced by a cecal ligation and puncture (CLP) in a first group of anesthetized rats. After the same CLP, a second group received a selective iNOS inhibitor (L-NIL). Control rats were sham operated or sham operated with L-NIL administration. While NO concentration was measured every 2 min by a NO-sensitive electrode over 7h following CLP, the liver microcirculation was recorded by a laser-Doppler flowmeter. CLP induced a severe septic shock with hypotension occurring at a mean time of 240 min after CLP. At the same time, an increase in liver NO concentration was observed, whereas a decrease in microvascular liver perfusion was noted. In the septic shock group, L-NIL administration induced an increase in arterial pressure whereas the liver NO concentration returned to baseline values. In addition, shock groups experienced an increase in iNOS mRNA. These data showed a close temporal relationship between the increase in liver NO concentration and the microvascular alteration taking place in the early period of septic shock induced by CLP. The iNOS isoform is involved in this NO increase.


Subject(s)
Cecum/surgery , Liver/metabolism , Nitric Oxide/analysis , Punctures , Shock, Septic/physiopathology , Animals , Disease Models, Animal , Electrodes , Ligation , Male , Nitric Oxide/biosynthesis , Peritonitis/physiopathology , Rats , Rats, Wistar , Time Factors
4.
J Chir (Paris) ; 144(5): 421-4, 2007.
Article in French | MEDLINE | ID: mdl-18065898

ABSTRACT

INTRODUCTION: In patients with an abdominal knife wound, the main problem is to determine whether the abdominal trauma is penetrating. The aim of this work is to study the safety of the laparoscopic approach in the management of abdominal knife trauma. MATERIALS: A laparoscopy was performing in sixty patients. Patients were dispatched in four categories according to the laparoscopic findings. A laparotomy was performed after laparoscopy in case of peritoneal tear. RESULTS: Unnecessary laparotomy was avoided in 58% of the patients. The follow-up was favourable with nil mortality and a low morbidity (3%). CONCLUSION: Laparoscopic management of abdominal wound knife trauma is a reliable approach to identify a peritoneum tear. This specific situation requires a laparotomy to look for an intra abdominal tear.


Subject(s)
Abdominal Injuries/surgery , Laparoscopy , Wounds, Stab/surgery , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Retrospective Studies , Wounds, Stab/diagnosis
5.
J Hazard Mater ; 146(3): 624-9, 2007 Jul 31.
Article in English | MEDLINE | ID: mdl-17532130

ABSTRACT

Photocatalysis is efficient in several fields. Firstly, in selective mild oxidation: oxidation of gas and liquid hydrocarbons (alkanes, alkenes, cyclo-alkanes, aromatics) into aldehydes and ketons. Primary and secondary alcohols are also oxidized into their corresponding aldehydes or ketones. The high selectivity was ascribed to a photoactive neutral, atomic oxygen species. Once platinized (only 0.5wt.% Pt) titania may catalyze reactions involving hydrogen (deuterium-alkane isotopic exchange and alcohol dehydrogenation). For fine chemicals, high initial selectivities enable titania to address most of the twelve principles of "green chemistry", such as the synthesis of 4-tert-butyl-benzaldehyde, an important intermediate in perfume industry by direct selective oxidation of 4-tert-butyl-toluene with air. A new field recently appeared: thio-photocatalysis. Oxygen was replaced by sulfur, using H(2)S as a convenient and reactive source. For instance, the conversion of propene in 1-propanthiol was successfully obtained. The reaction was performed using either CdS or TiO(2). The latter was much more active than CdS. In environmental photocatalysis, titania becomes a total oxidation catalyst once in presence of water because of the photogeneration of OH radicals by neutralization of OH(-) surface groups by positive holes. Many toxic inorganic ions are oxidized in their harmless upper oxidized state. The total degradation of organic pollutants (pesticides, herbicides, insecticides, fungicides, dyes, etc. ...) is the main field of water photocatalytic decontamination. The UVA solar spectrum can de advantageously used as demonstrated by many campaigns performed in the solar pilot plant at the "Plataforma Solar de Almeria" (Spain).


Subject(s)
Titanium/chemistry , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/radiation effects , Catalysis , Oxidation-Reduction , Photochemistry , Ultraviolet Rays
6.
Am J Physiol Regul Integr Comp Physiol ; 287(4): R870-7, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15178544

ABSTRACT

King penguins (Aptenodytes patagonicus) may fast for up to 30 days during their breeding period. As such extended fasting may affect the relationship between the rate of O(2) consumption (Vo(2)) and heart rate (f(H)), five male king penguins were exercised at various speeds on repeated occasions during a fasting period of 24-31 days. In addition, Vo(2) and f(H) were measured in the same animals during rest in cold air and water (4 degrees C). Vo(2) and f(H) at rest and Vo(2) during exercise decreased with fasting. There was a significant relation between Vo(2) and f(H) (r(2) = 0.56) that was improved by including speed, body mass (M(b)), number of days fasting (t), and a cross term between f(H) and t (r(2) = 0.92). It was concluded that there was a significant change in the Vo(2)-f(H) relationship with fasting during exercise. As t is measurable in the field and was shown to be significant and, therefore, a practical covariate, a regression equation for use when birds are ashore was obtained by removing speed and M(b). When this equation was used, predicted Vo(2) was in good agreement with the observed data, with an overall error of 3.0%. There was no change in the Vo(2)-f(H) relationship in penguins at rest in water.


Subject(s)
Birds/physiology , Fasting/physiology , Heart Rate/physiology , Oxygen Consumption/physiology , Algorithms , Animals , Body Weight/physiology , Carbon Dioxide/metabolism , Organ Size/physiology , Physical Exertion/physiology , Respiratory Mechanics/physiology , Rest/physiology
7.
Am J Physiol Regul Integr Comp Physiol ; 283(5): R1245-53, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12376419

ABSTRACT

Thermogenic endurance and development of metabolic cold adaptation in birds may critically depend on their ability to synthesize and use fatty acids (FA) as fuel substrates. Hepatic lipogenesis and the capacity to oxidize FA in thermogenic tissues were measured in cold-acclimated (CA) ducklings (Cairina moschata) showing original mechanisms of metabolic cold adaptation in the absence of brown adipose tissue, the specialized thermogenic tissue of rodents. The rate of FA synthesis from [U-(14)C]glucose and from [1-(14)C]acetate, measured in incubated hepatocytes isolated from 5-wk-old thermoneutral (TN; 25 degrees C) or CA (4 degrees C) fed ducklings, was higher than in other species. Hepatic de novo lipogenesis was further increased by cold acclimation with both glucose (+194%) and acetate (+111%) as precursor. Insulin slightly increased (+11-14%) hepatic lipogenesis from both precursors in CA ducklings, whereas glucagon was clearly inhibitory (-29 to -51%). Enhanced de novo lipogenesis was associated with higher (+171%) hepatocyte activity of glucose oxidation and larger capacity (+50 to +100%) of key lipogenic enzymes. The potential for FA oxidation was higher in liver (+61%) and skeletal muscle (+29 to +81%) homogenates from CA than from TN ducklings, suggesting that the higher hepatic lipogenesis may fuel oxidation in thermogenic tissues. Present data underline the high capacity to synthesize lipids from glucose in species like muscovy ducks susceptible to hepatic steatosis. Lipogenic capacity can be further increased in the cold and may represent an important step in the metabolic adaptation to cold of growing ducklings.


Subject(s)
Acclimatization/physiology , Cold Temperature , Ducks/physiology , Hepatocytes/metabolism , Lipids/biosynthesis , Acetyl-CoA Carboxylase/metabolism , Animals , Body Temperature Regulation/physiology , Cell Separation , Fatty Acid Synthases/metabolism , Fatty Acids/metabolism , Glucagon/physiology , Glucose/metabolism , Glucosephosphate Dehydrogenase/metabolism , Insulin/physiology , Kinetics , Liver/metabolism , Liver/physiology , Male , Muscle, Skeletal/enzymology , Muscle, Skeletal/metabolism , Oleic Acid/metabolism , Oxidation-Reduction
9.
Article in English | MEDLINE | ID: mdl-11282327

ABSTRACT

The control of hepatic metabolism by substrates and hormones was assessed in perfused liver from young Muscovy ducklings. Studies were performed in fed or 24-h fasted 5-week-old thermoneutral (25 degrees C; TN) or cold-acclimated ducklings (4 degrees C; CA) and results were compared with those obtained in rats. Basal oxygen uptake of perfused liver (LVO2) was higher after cold acclimation both in fed (+65%) and 24-h fasted (+29%) ducklings and in 24-h fasted rats (+34%). Lactate (2 mM), the main gluconeogenic substrate in birds, similarly increased LVO2 in both TN and CA ducklings and the effect was larger after fasting. Both glucagon and norepinephrine dose-dependently increased LVO2 in ducklings and rats, but cold acclimation did not improve liver response and liver sensitivity to norepinephrine in ducklings was even reduced in CA animals. Liver contribution to glucagon-induced thermogenesis in vivo was estimated to be 22% in TN and 12% in CA ducklings. Glucagon stimulated gluconeogenesis from lactate in duckling liver and the stimulation was 2.2-fold higher in CA than in TN fasted birds. These results indicate a stimulated hepatic oxidative metabolism in CA ducklings but hepatic glucagon-induced thermogenesis (as measured by LVO2) was not improved. A role of the liver is suggested in duckling metabolic acclimation to cold through an enhanced hepatic gluconeogenesis under glucagon control.


Subject(s)
Ducks/physiology , Glucose/metabolism , Liver/metabolism , Oxygen/metabolism , Adaptation, Physiological , Animals , Cold Temperature , Fasting , Glucagon/metabolism , In Vitro Techniques , Lactic Acid/pharmacology , Liver/drug effects , Male , Perfusion
10.
Biochem J ; 353(Pt 3): 441-4, 2001 Feb 01.
Article in English | MEDLINE | ID: mdl-11171038

ABSTRACT

The cDNA of an uncoupling protein (UCP) homologue was obtained by screening a chicken skeletal-muscle library. The predicted 307-amino-acid sequence of avian UCP (avUCP) is 55, 70, 70 and 46% identical with mammalian UCP1, UCP2 and UCP3 and plant UCP respectively. avUCP mRNA expression is restricted to skeletal muscle and its abundance was increased 1.3-fold in a chicken line showing diet-induced thermogenesis, and 3.6- and 2.6-fold in cold-acclimated and glucagon-treated ducklings developing muscle non-shivering thermogenesis respectively. The present data support the implication of avUCP in avian energy expenditure.


Subject(s)
Avian Proteins , Carrier Proteins/physiology , Mitochondrial Proteins , Muscle, Skeletal/physiology , Thermogenesis/physiology , Amino Acid Sequence , Animals , Base Sequence , Blotting, Northern , Carrier Proteins/chemistry , Carrier Proteins/genetics , Chickens , DNA Primers , DNA, Complementary , Mitochondrial Uncoupling Proteins , Molecular Sequence Data , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction , Sequence Homology, Amino Acid
11.
Lipids ; 35(10): 1099-106, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11104016

ABSTRACT

The phospholipid fatty acid (FA) composition and functional properties of skeletal muscle and liver mitochondria were examined in cold-acclimated (CA, 4 degrees C) ducklings. Phospholipid FA of isolated muscle mitochondria from CA birds were longer and more unsaturated than those from thermoneutral (TN, 25 degrees C) reared ducklings. The rise in long-chain and polyunsaturated FA (PUFA, mainly 20:4n-6) was associated with a higher State 4 respiration rate and a lower respiratory control ratio (RCR). Hepatic mitochondria, by contrast, were much less affected by cold acclimation. The cold-induced changes in phospholipid FA profile and functional properties of muscle mitochondria were reproduced by giving TN ducklings a diet enriched in grapeseed oil (GO, rich in n-6 FA), suggesting a causal relationship between the membrane structure and mitochondrial functional parameters. However, hepatic mitochondria from ducklings fed the GO diet also showed an enrichment in long-chain PUFA but opposite changes in their biochemical characteristics (lower State 4, higher RCR). It is suggested that the differential modulation of mitochondrial functional properties by membrane lipid composition between skeletal muscle and liver may depend on muscle-specific factors possibly interacting with long-chain PUFA and affecting the proton leakiness of mitochondrial membranes.


Subject(s)
Cold Temperature , Diet , Fatty Acids/pharmacology , Mitochondria, Liver/chemistry , Muscle, Skeletal/chemistry , Phospholipids/chemistry , Plant Oils/chemistry , Plant Oils/pharmacology , Animals , Ducks , Fatty Acids, Unsaturated/metabolism , Intracellular Membranes/metabolism , Male , Temperature , Time Factors
12.
Mol Cell Biochem ; 208(1-2): 139-42, 2000 May.
Article in English | MEDLINE | ID: mdl-10939637

ABSTRACT

Brown adipose tissue (BAT) is implicated in both cold-induced thermogenesis and regulation of energy expenditure and is mainly controlled by sympathetic innervation. To clarify the permissive and/or complementary roles of glucagon in cold-induced BAT activation, glucagon receptor gene expression and its modulation by sympathetic activity were investigated in rats. One pad of interscapular BAT was surgically denervated while the other pad was sham operated, then rats were either cold-exposed (CE) for 1 week at 4 degrees C or kept near thermoneutrality (25 degrees C, TN). Using a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay, it was shown that cold exposure decreased (-44%) the relative abundance of BAT glucagon receptor mRNA, an effect which was prevented by unilateral surgical sympathectomy of BAT. The present results show a negative control by sympathetic nervous activity of glucagon receptor gene expression and/or of glucagon receptor mRNA stability in BAT of cold-exposed rats. The down-regulation of glucagon receptor expression during cold exposure does not support a major role of the peptide in the thermogenic control of BAT.


Subject(s)
Adipose Tissue, Brown/innervation , Adipose Tissue, Brown/metabolism , Cold Temperature , RNA, Messenger/metabolism , Receptors, Glucagon/genetics , Receptors, Glucagon/metabolism , Sympathetic Nervous System/physiology , Adipose Tissue, Brown/anatomy & histology , Adipose Tissue, Brown/surgery , Animals , Body Weight , Gene Expression Regulation , Male , Organ Size , RNA/metabolism , Rats , Rats, Wistar , Reverse Transcriptase Polymerase Chain Reaction , Sympathectomy
13.
Biochem Biophys Res Commun ; 266(2): 518-22, 1999 Dec 20.
Article in English | MEDLINE | ID: mdl-10600534

ABSTRACT

The effect of long-term hindlimb unloading (2 or 5 week) on the expression of uncoupling protein-3 (UCP3) gene was investigated in rat skeletal muscles. The interaction of hindlimb unloading and thyroid status was also investigated at 2 weeks. Whatever the duration, mechanical unloading induced a similar increase in UCP3 mRNA relative abundance in the slow-twitch soleus (SOL) muscle (+80%, P < 0.05), whereas no effect was observed in the fast-twitch extensor digitorum longus (EDL) muscle. Hypothyroidism down-regulated while hyperthyroidism up-regulated UCP3 mRNA relative abundance in both SOL and EDL muscles, but thyroid status did not prevent the up-regulation of UCP3 induced by 2 weeks of suspension. These data therefore indicate for the first time that long-term hindlimb unloading up-regulates muscle UCP3 gene expression in a muscle-specific manner which is independent of thyroid status.


Subject(s)
Carrier Proteins/genetics , Muscle, Skeletal/metabolism , RNA, Messenger/metabolism , Animals , Female , Gene Expression Regulation/genetics , Hindlimb , Hyperthyroidism/genetics , Hypothyroidism/genetics , Ion Channels , Mitochondrial Proteins , Rats , Rats, Wistar , Reverse Transcriptase Polymerase Chain Reaction , Stress, Physiological/metabolism , Uncoupling Protein 3
14.
Am J Physiol ; 277(6): R1733-40, 1999 12.
Article in English | MEDLINE | ID: mdl-10600921

ABSTRACT

The characteristics and modulation of glucose transport were investigated in skeletal muscles of 5-wk-old Muscovy ducklings (Cairina moschata). Glucose uptake by sarcolemmal vesicles isolated from gastrocnemius muscle followed typical Michaelis-Menten kinetics with a K(m) value (17 mM) similar to that described in equivalent mammalian preparations. Western blot analysis of duckling sarcolemma using antibodies directed against rat GLUT-4 transporter revealed an immunoreactive protein of similar molecular mass (45 kDa) to that present in rats. When ducklings were killed in the postabsorptive state, GLUT-4 homologous protein was located predominantly (80%) in intracellular membranes. Insulin stimulation of a perfused leg muscle preparation in vitro led to the translocation of GLUT-4 homologous proteins from intracellular pools to the sarcolemma, with a subsequent increase in glucose uptake by sarcolemmal vesicles and perfused muscles. Glucose transport was positively controlled by the metabolic needs of skeletal muscle as reflected by the increased glucose uptake of sarcolemmal vesicles isolated from cold-acclimated ducklings. Present results, therefore, demonstrate, for the first time in an avian species, the existence in skeletal muscle of a glucose transporter showing molecular and functional homologies with the mammalian GLUT-4 transporter.


Subject(s)
Monosaccharide Transport Proteins/metabolism , Muscle Proteins , Muscle, Skeletal/physiology , Acclimatization , Animals , Ducks , Glucose/metabolism , Glucose Transporter Type 1 , Glucose Transporter Type 4 , Humans , In Vitro Techniques , Insulin/pharmacology , Insulin, Regular, Pork , Intracellular Membranes/metabolism , Kinetics , Male , Molecular Weight , Monosaccharide Transport Proteins/chemistry , Muscle, Skeletal/drug effects , Muscle, Skeletal/metabolism , Rats , Sarcolemma/metabolism
15.
Can J Physiol Pharmacol ; 77(6): 414-21, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10537227

ABSTRACT

To determine whether newborn pigs are able to display adequate cardiovascular adjustments favouring shivering thermogenesis in skeletal muscles soon after birth, regional blood flow and fractional distribution of cardiac output were determined in 1-day-old (n = 6) and 5-day-old (n = 6) conscious piglets at thermal neutrality and during cold exposure, using coloured microspheres. Five-day-old piglets stayed with the sow before the experiment. The cold challenge was designed to induce a similar increase (approximately +90%) in heat production at both ages. Skeletal muscle blood flow increased with both age (p < 0.05) and cold exposure (p < 0.001), with the effect of cold being more pronounced in 5-day-old piglets than in 1-day-old piglets (+60%, p < 0.05). The difference between individual muscles increased with age, with fractional blood flow being 41% higher in rhomboideus than in longissimus thoracis muscle during cold exposure in 5-day-old piglets (p < 0.05). Cardiac output was similar at both ages and increased by 23% in the cold (p < 0.001). At 1 day of age, there was no redistribution of cardiac output among the internal organs during the cold challenge, while at 5 days of age, the increase in muscle fractional blood flow was associated with a reduction (p < 0.05) in the fraction of cardiac output reaching the skin (-24%), the small intestine (-21%), and the liver (-20%). In conclusion, these results suggest that there is a rapid postnatal improvement of cardiovascular adjustments favouring blood perfusion and probably heat production during cold-induced shivering in the most oxidative muscles studied. This cardiovascular response may play a role in the postnatal enhancement of thermoregulation in piglets.


Subject(s)
Muscle, Skeletal/blood supply , Shivering/physiology , Adipose Tissue/blood supply , Age Factors , Animals , Body Temperature , Cardiac Output , Cold Temperature , Female , Regional Blood Flow , Skin/blood supply , Swine
16.
FEBS Lett ; 444(2-3): 181-5, 1999 Feb 12.
Article in English | MEDLINE | ID: mdl-10050755

ABSTRACT

The control of uncoupling protein-1, -2 and -3 (UCP-1, UCP-2, UCP-3) mRNA levels by sympathetic innervation in rats was investigated by specific and sensitive RT-PCR assays. In rats reared at thermoneutrality (25 degrees C), unilateral surgical sympathetic denervation of interscapular brown adipose tissue (BAT) markedly reduced the UCP-1 mRNA level (-38%) as compared with the contralateral innervated BAT pad, but was without significant effect on UCP-2 and -3 mRNA levels. Cold exposure (7 days, 4 degrees C) markedly increased UCP-1 (+180%), UCP-2 (+115%) and UCP-3 (+195%) mRNA levels in interscapular BAT. Unilateral sympathetic denervation prevented the cold-induced rise in BAT UCP-1 and UCP-2 mRNAs, but not that in BAT UCP-3 mRNA. Results were confirmed by Northern blot analysis. These data indicate a differential endocrine control of UCP-1, UCP-2 and UCP-3 gene expression in rat BAT both at thermoneutrality and during prolonged cold exposure.


Subject(s)
Adipose Tissue, Brown/metabolism , Carrier Proteins/genetics , Gene Expression Regulation/genetics , Membrane Proteins/genetics , Membrane Transport Proteins , Mitochondrial Proteins , Proteins/genetics , Sympathetic Nervous System/physiology , Analysis of Variance , Animals , Cold Temperature , Ion Channels , Male , RNA, Messenger/genetics , Rats , Rats, Wistar , Sympathectomy , Temperature , Uncoupling Protein 1 , Uncoupling Protein 2 , Uncoupling Protein 3
17.
Physiol Biochem Zool ; 72(2): 170-8, 1999.
Article in English | MEDLINE | ID: mdl-10068620

ABSTRACT

Energetic adaptation to fasting in the cold has been investigated in a nocturnal raptor, the barn owl (Tyto alba), during winter. Metabolic rate and body temperature (Tb) were monitored in captive birds, (1) after acute exposure to different ambient temperatures (Ta), and (2) during a prolonged fast in the cold (4 degrees C), to take into account the three characteristic phases of body fuel utilization that occur during a long-term but reversible fast. In postabsorptive birds, metabolic rate in the thermoneutral zone was 4. 1+/-0.1 W kg-1 and increased linearly below a lower critical temperature of 23 degrees C. Metabolic rate was 70% above basal at +4 degrees C Ta. Wet thermal conductance was 0.22 W kg-1 degrees C-1. During fasting in the cold, the mass-specific resting metabolic rate decreased by 16% during the first day (phase I) and remained constant thereafter. The amplitude of the daily rhythm in Tb was only moderately increased during phase II, with a slight lowering (0. 6 degrees C) in minimal diurnal Tb, but rose markedly in phase III with a larger drop (1.4 degrees C) in minimal diurnal Tb. Refeeding the birds ended phase III and reversed the observed changes. These results indicate that diurnal hypothermia may be used in long-term fasting barn owls and could be triggered by a threshold of body lipid depletion, according to the shift from lipid to protein fuel metabolism occurring at the phase II/phase III transition. The high cost of regulatory thermogenesis and the limited use of hypothermia during fasting may contribute to the high mortality of barn owls during winter.


Subject(s)
Body Temperature Regulation/physiology , Body Temperature , Energy Metabolism , Fasting/physiology , Strigiformes/physiology , Animals , Cold Temperature , Mortality , Seasons
18.
FEBS Lett ; 439(3): 258-62, 1998 Nov 20.
Article in English | MEDLINE | ID: mdl-9845333

ABSTRACT

Gastrocnemius subsarcolemmal and intermyofibrillar mitochondria were isolated from 5-week-old cold-acclimated and thermoneutral control ducklings. In vitro respiration (polarography) and ATP synthesis (bioluminescence) were determined at 25 degrees C. Subsarcolemmal mitochondria showed a higher state 4 respiration and lower respiratory control and ADP/O ratio in cold-acclimated than in thermoneutral ducklings. Palmitate decreased the rate of ATP synthesis in both mitochondrial populations to about 30% of maximal but failed to abolish this process even at high concentrations. It is suggested that both expensive ATP synthesis and increased ATP hydrolysis could contribute synergistically to muscle non-shivering thermogenesis in cold-acclimated ducklings.


Subject(s)
Acclimatization , Cold Temperature , Energy Metabolism , Mitochondria, Muscle/metabolism , Muscle, Skeletal/metabolism , Palmitates/metabolism , Adenosine Triphosphate/biosynthesis , Animals , Cell Respiration , Ducks , Male , Membrane Potentials , Muscle Fibers, Skeletal/metabolism , Muscle, Skeletal/physiology , Sarcolemma/metabolism
19.
Mol Cell Endocrinol ; 144(1-2): 71-81, 1998 Sep 25.
Article in English | MEDLINE | ID: mdl-9863628

ABSTRACT

The influence of thyroid status on glucagon receptor mRNA levels was investigated in rats using a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Glucagon receptor mRNA was detected in liver, brown and white adipose tissues (BAT and WAT) and brain. In BAT and WAT, pharmacologically-induced moderate hypothyroidism resulted in a marked reduction in the relative abundance of glucagon receptor mRNA. Short-term treatment of hypothyroid rats with exogenous 3,3',5'-triiodo-L-thyronine (T3), resulting in a marked hyperthyroidism, reversed the phenomenon in BAT while the reversal was only partial in WAT. In the liver, there was no significant effect of mild hypothyroidism while there was a positive effect of hyperthyroidism. In brain, the relative tissue abundance of glucagon receptor mRNA was not affected by the large changes in plasma T3. The present results therefore indicate that thyroid status may modulate the relative abundance of glucagon receptor mRNA in a tissue-specific manner.


Subject(s)
RNA, Messenger/metabolism , Receptors, Glucagon/genetics , Thyroid Diseases/metabolism , Thyroid Gland/metabolism , Adipose Tissue/drug effects , Adipose Tissue/metabolism , Animals , Body Weight/drug effects , Brain/drug effects , Brain/metabolism , Gene Expression/drug effects , Iopanoic Acid/pharmacology , Liver/drug effects , Liver/metabolism , Male , Organ Specificity , Propylthiouracil/pharmacology , RNA, Messenger/genetics , Rats , Rats, Wistar , Reverse Transcriptase Polymerase Chain Reaction , Thyroid Diseases/chemically induced , Thyroid Diseases/drug therapy , Thyroid Gland/drug effects , Triiodothyronine/administration & dosage , Triiodothyronine/blood , Triiodothyronine/pharmacology
20.
Am J Physiol ; 275(3): R683-90, 1998 09.
Article in English | MEDLINE | ID: mdl-9728063

ABSTRACT

In cold-acclimated (CA) birds, lipids play a crucial role in regulatory thermogenesis by acting both as substrates for and activators of thermogenic processes. The capacity to supply lipids to thermogenic tissues, which could limit cold thermogenesis, was assessed in CA ducklings (5 wk old, 4 degrees C) and compared with thermoneutral controls (TN, 25 degrees C). In CA ducklings, basal lipolytic activity of adipose tissue fragments was higher (202 +/- 9 vs. 130 +/- 14 nmol glycerol released . 100 mg tissue-1 . h-1, +55%) than in TN controls, while glucagon had a much higher stimulatory effect (+140 to +500% depending on dose). This was consistent with increased plasma levels of nonesterified fatty acids (FA, +57%) and glycerol (+31%) in vivo. In vitro endothelial lipase activity per organ was higher in CA than in TN ducklings in red gastrocnemius muscle (6.3 +/- 0.6 vs. 3.5 +/- 0.3 microeq nonesterified FA released per hour, +80%) and liver (+55%). The intracellular FA-binding capacity of (12-18 kDa) proteins was higher in gastrocnemius muscle (+43%) and liver (+74%) from CA ducklings. In gastrocnemius, it was linked to a higher content (21 +/- 2 vs. 15 +/- 2 microg/mg protein, +37%) of an intracellular 15.4-kDa FA-binding protein. These in vitro results indicate that coordinated increases in FA supply from adipose tissue, cellular uptake of lipoprotein-derived FA, and intracellular FA transport capacity occur in CA ducklings endowed with higher thermogenic capacity and cold endurance.


Subject(s)
Acclimatization , Cold Temperature , Ducks/metabolism , Fatty Acids/metabolism , Neoplasm Proteins , Adipose Tissue/metabolism , Animals , Biological Transport , Body Temperature Regulation , Carrier Proteins/analysis , Carrier Proteins/isolation & purification , Endothelium, Vascular/enzymology , Fatty Acid-Binding Proteins , Fatty Acids, Nonesterified/blood , Glucagon/pharmacology , Glycerol/blood , Glycerol/metabolism , Lipase/metabolism , Lipids/blood , Lipolysis , Liver/enzymology , Male , Muscle, Skeletal/chemistry , Muscle, Skeletal/enzymology , Myelin P2 Protein/analysis , Myelin P2 Protein/isolation & purification
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