Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 37
Filter
1.
Occup Med (Lond) ; 74(1): 113-119, 2024 02 19.
Article in English | MEDLINE | ID: mdl-38330159

ABSTRACT

BACKGROUND: Prior studies showed that during the coronavirus disease 2019 (COVID-19) pandemic healthcare workers had a higher risk of developing post-traumatic stress disorder (PTSD) symptoms. However, studies conducted among doctors several years after the beginning of the COVID-19 pandemic are scarce. AIMS: To evaluate the prevalence of PTSD among hospital doctors and to describe potential explanatory factors. METHODS: The Protec-Cov study was an observational, cross-sectional, multicentre study, which used an anonymous online questionnaire to evaluate PTSD in doctors from six hospitals in France between December 2021 and March 2022. The presence of PTSD was assessed using the Post-traumatic Stress Disorder Checklist Scale (PCLS) questionnaire with a cut-off of 44. RESULTS: Among the 307 doctors included, 18% presented a PCLS ≥44. The multivariate analysis showed that factors associated with a PCLS ≥44 were having a higher workload than before the COVID-19 pandemic (odds ratio [OR] = 4.75; 95% confidence interval [CI] 1.68-13.38), not feeling recognized within the professional environment (OR = 2.83; 95% CI 1.26-6.33), and feeling isolated because of the lockdown (OR = 4.2; 95% CI 1.97-8.95). Approximately 30% of hospital doctors (n = 91) felt a need for psychological support but only 31% of them (n = 28) received support. CONCLUSIONS: Based on our findings, a high prevalence of PTSD was observed among hospital doctors 2 years after the beginning of the COVID-19 pandemic. This study supports an early diagnosis of PTSD in this category of healthcare workers and warrants further study.


Subject(s)
COVID-19 , Stress Disorders, Post-Traumatic , Humans , COVID-19/epidemiology , COVID-19/complications , Stress Disorders, Post-Traumatic/epidemiology , Stress Disorders, Post-Traumatic/etiology , Pandemics , Cross-Sectional Studies , Communicable Disease Control , Hospitals
2.
Crit Rev Clin Lab Sci ; 58(3): 207-224, 2021 05.
Article in English | MEDLINE | ID: mdl-33929278

ABSTRACT

In the clinical laboratory, knowledge of and the correct use of clot activators and anticoagulant additives are critical to preserve and maintain samples in optimal conditions prior to analysis. In 2017, the Latin America Confederation of Clinical Biochemistry (COLABIOCLI) commissioned the Latin American Working Group for Preanalytical Phase (WG-PRE-LATAM) to study preanalytical variability and establish guidelines for preanalytical procedures to be applied by clinical laboratories and health care professionals. The aim of this critical review, on behalf of COLABIOCLI WG-PRE-LATAM, is to provide information to understand the mechanisms of the interactions and reactions that occur between blood and clot activators and anticoagulant additives inside evacuated tubes used for laboratory testing. Clot activators - glass, silica, kaolin, bentonite, and diatomaceous earth - work by surface dependent mechanism whereas extrinsic biomolecules - thrombin, snake venoms, ellagic acid, and thromboplastin - start in vitro coagulation when added to blood. Few manufacturers of evacuated tubes state the type and concentration of clot activators used in their products. With respect to anticoagulant additives, sodium citrate and oxalate complex free calcium and ethylenediaminetetraacetic acid chelates calcium. Heparin potentiates antithrombin and hirudin binds to active thrombin, inactivating the thrombin irreversibly. Blood collection tubes have improved continually over the years, from the glass tubes containing clot activators or anticoagulant additives that were prepared by laboratory personnel to the current standardized evacuated systems that permit more precise blood/additive ratios. Each clot activator and anticoagulant additive demonstrates specific functionality, and both manufacturers of tubes and laboratory professional strive to provide suitable interference-free sample matrices for laboratory testing. Both manufacturers of in vitro diagnostic devices and laboratory professionals need to understand all aspects of venous blood sampling so that they do not underestimate the impact of tube additives on laboratory testing.


Subject(s)
Anticoagulants , Blood Specimen Collection , Anticoagulants/pharmacology , Blood Coagulation , Humans , Phlebotomy
3.
EJIFCC ; 29(1): 26-35, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29765284

ABSTRACT

OBJECTIVE: The aim of the present study was to evaluate the possible association between the Q223R Leptin receptor (LEPR) polymorphism (A>G; rs1137101) and leptin levels in patients with rheumatoid arthritis (RA) from Western Mexico. METHODS: A cross-sectional study was performed with 70 RA patients and 74 controls subject (CS). Disease activity was evaluated using DAS28 score, the Q223R LEPR polymorphism was determined by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and serum leptin levels, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and rheumatoid factor (RF) were quantified. RESULTS: RA patients had significant high serum leptin levels compared with CS; leptin levels correlated strongly with body composition measures, but not with inflammatory markers, disease evolution, and activity. The genotype and allele frequencies of the Q223R LEPR polymorphism were not associated with RA. Similarly, leptin levels did not differ between Q223R LEPR genotypes. CONCLUSION: The LEPR Q223R polymorphism was not associated with RA risk in patients from Mexican population, even though high levels of serum leptin were present and these could explain the low weight observed in RA patients when they were compared to control subjects. However, the serum leptin levels did not correlate with inflammatory markers, severity and disease evolution.

4.
Clin Exp Med ; 18(2): 229-235, 2018 May.
Article in English | MEDLINE | ID: mdl-28965181

ABSTRACT

Psoriatic arthritis (PsA) is an autoimmune inflammatory disease associated with psoriasis. The cause of this pathology is still unknown, but research suggests the diseases are caused by a deregulated cytokine production. MIF is a cytokine associated with immunomodulation of Th1, Th2, and Th17 cytokine profiles in inflammatory diseases. Based on this knowledge, the aim of this study was to determine the association of MIF and TNFA expression with Th1, Th2, and Th17 cytokine profiles in serum levels of PsA patients. A cross-sectional study was performed in 50 PsA patients and 30 control subjects (CS). The cytokine profiles were quantified by BioPlex MagPix system and the mRNA expression levels by real-time PCR. TNFA mRNA expression was 138.81-folds higher in PsA patients than CS (p < 0.001). Regarding MIF mRNA expression, no significant differences were observed; however, a positive correlation was identified between MIF mRNA expression and PsA time of evolution (r = - 0.53, p = 0.009). An increase of Th1 (IFNγ: PsA = 37.1 pg/mL vs. CS = 17 pg/mL, p < 0.05; TNFα: PsA = 24.6 pg/mL vs. CS = 9.8 pg/mL, p < 0.0001) and Th17 cytokine profiles (IL-17: PsA = 6.4 pg/mL vs. CS = 2.7 pg/mL, p < 0.05; IL-22: PsA = 8.4 pg/mL vs. CS = 1.8 pg/mL, p < 0.001), were found in PsA patients. Th2 cytokines were not significantly different in both groups. In conclusion, a high expression of TNFA mRNA, as well as an increase of Th1 and Th17 cytokine profiles evaluated by IFNγ, TNFα, IL-17, and IL-22 cytokines, was observed in PsA patients.


Subject(s)
Arthritis, Psoriatic/genetics , Cytokines/blood , Intramolecular Oxidoreductases/genetics , Macrophage Migration-Inhibitory Factors/genetics , Tumor Necrosis Factor-alpha/genetics , Up-Regulation , Adult , Arthritis, Psoriatic/blood , Arthritis, Psoriatic/immunology , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Th1 Cells/immunology , Th17 Cells/immunology , Th2 Cells/immunology
6.
Br J Sports Med ; 46(11): 770-9, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22685119

ABSTRACT

Challenging environmental conditions, including heat and humidity, cold, and altitude, pose particular risks to the health of Olympic and other high-level athletes. As a further commitment to athlete safety, the International Olympic Committee (IOC) Medical Commission convened a panel of experts to review the scientific evidence base, reach consensus, and underscore practical safety guidelines and new research priorities regarding the unique environmental challenges Olympic and other international-level athletes face. For non-aquatic events, external thermal load is dependent on ambient temperature, humidity, wind speed and solar radiation, while clothing and protective gear can measurably increase thermal strain and prompt premature fatigue. In swimmers, body heat loss is the direct result of convection at a rate that is proportional to the effective water velocity around the swimmer and the temperature difference between the skin and the water. Other cold exposure and conditions, such as during Alpine skiing, biathlon and other sliding sports, facilitate body heat transfer to the environment, potentially leading to hypothermia and/or frostbite; although metabolic heat production during these activities usually increases well above the rate of body heat loss, and protective clothing and limited exposure time in certain events reduces these clinical risks as well. Most athletic events are held at altitudes that pose little to no health risks; and training exposures are typically brief and well-tolerated. While these and other environment-related threats to performance and safety can be lessened or averted by implementing a variety of individual and event preventative measures, more research and evidence-based guidelines and recommendations are needed. In the mean time, the IOC Medical Commission and International Sport Federations have implemented new guidelines and taken additional steps to mitigate risk even further.


Subject(s)
Altitude , Body Temperature Regulation/physiology , Cold Temperature/adverse effects , Hot Temperature/adverse effects , Sports , Acclimatization/physiology , Altitude Sickness/prevention & control , Athletic Performance/physiology , Cold Climate/adverse effects , Dehydration/prevention & control , Exercise/physiology , Frostbite/prevention & control , Health Facilities/supply & distribution , Heat Stress Disorders/prevention & control , Humans , Hypothermia/prevention & control , Respiration Disorders/prevention & control , Risk Factors
7.
J Fr Ophtalmol ; 31(6 Pt 1): 585-90, 2008 Jun.
Article in French | MEDLINE | ID: mdl-18772809

ABSTRACT

PURPOSE: To compare multifocal electroretinogram (mfERG) amplitudes with the Gold Foil electrode and ERG-jet electrode. To study mfERG amplitude changes between two successive records (intraindividual reproducibility). METHODS: The right eye of 27 normal subjects was examined. Two mfERG recordings using the 61-hexagon strategy (Vision Monitor, Métrovision, France) were made with both ERG-jet and Gold Foil electrodes. N1 and P1 wave amplitudes were analyzed in the central response and in four concentric rings. Bland and Altman analysis was used for the reproducibility study. RESULTS: MfERG amplitudes were significantly lower with the Gold Foil electrode, which averaged 72+/-10% of ERG-jet amplitudes. For N1 and P1 waves, the percentage change for the intraindividual reproducibility study was 9.1% and 6.7%, respectively, with the ERG-jet electrode and 18.2% and 13.5%, respectively, with the Gold Foil electrode. CONCLUSION: MfERG amplitudes were larger and more reproducible with an ERG-jet electrode than with a Gold Foil electrode. The limits of agreement of each ring can be used in clinical practice to determine whether the variation between two mfERG recordings over time is normal, which could reflect a retinal disorder.


Subject(s)
Electrodes , Electroretinography/methods , Adolescent , Adult , Electroretinography/instrumentation , Equipment Design , Gold , Humans , Male , Middle Aged , Reproducibility of Results , Young Adult
8.
J Clin Monit Comput ; 21(2): 91-101, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17186401

ABSTRACT

OBJECTIVE: Unexpected intraoperative movement may be detrimental during delicate surgery. This study tested retrospectively an algorithm based on beat-by-beat circulatory variables (incorporated into a Cardiovascular depth of anesthesia index: CARDEAN in relationship to unexpected movement, and compared its performance to that of the electroencephalogram (EEG)-derived index: BIS-XP 4.0. METHODS: 40 ASA I or II patients presenting for knee surgery had EEG (BIS XP 4.0), beat-by-beat (Finapres) finger non-invasive blood pressure (BP), conventional brachial BP and electrocardiogram (EKG) monitors attached. Anesthesia was induced and maintained with propofol and remifentanil. Before incision, the propofol concentration was set to maintain BIS < 60. From incision to emergence, the anesthesiologist was denied access to BIS or Finapres. Anesthesia adjustment was titrated at the discretion of the anesthesiologist according to conventional signs only: brachial BP, EKG, eyelash reflex, movement. Occurrences of movement and eye signs (divergence of eyeballs, tears, corneal reflex, eyelash reflex) were observed. The CARDEAN algorithm was written retrospectively and tested vs. BIS. RESULTS: 11 movements occurred in 8 patients. CARDEAN > 60 predicted movement in 30% of the cases, 15 to 274 s before movement (sensitivity: 100%, specificity: 95%; relative operating curve ROC = 0.98; prediction probability pk = 0.98). BIS > 60 predicted movement in 19% of cases (sensitivity: 64%; specificity: 94%, ROC: 0.85, pk: 0.85). CONCLUSION: Retrospectively, a cardiovascular index predicted unexpected intraoperative movements. Prospective validation is needed.


Subject(s)
Anesthesia/methods , Anesthetics, General/administration & dosage , Blood Pressure Determination/methods , Blood Pressure/drug effects , Heart Rate/drug effects , Monitoring, Intraoperative/methods , Movement/drug effects , Algorithms , Electroencephalography/drug effects , Electroencephalography/methods , Humans , Paralysis , Reproducibility of Results , Sensitivity and Specificity
9.
Eur J Appl Physiol ; 97(5): 527-34, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16775741

ABSTRACT

Energy substrate oxidation was measured using indirect respiratory calorimetry combined with tracer technique in five healthy young male subjects, during a 80-min exercise period on ergocycle with ingestion of 140 g of (13)C-labelled glucose, in normoxia and acute hypobaric hypoxia (445 mmHg or 4,300 m), at the same relative [77% V(.-)((O)(2)(max))] and absolute workload (161+/-8 W, corresponding to 77 and 54% V(.-)((O)(2)(max)) in hypoxia and normoxia). The oxidation rate of exogenous glucose was not significantly different in the three experimental situations: 21.4+/-2.9, 20.2+/-1.2 and 17.2+/-0.6 g over the last 40 min of exercise at approximately 77 and approximately 54% V(.-)((O)(2)(max)) in normoxia and in hypoxia, respectively, providing 12.5+/-1.5, 16.8+/-1.1 and 14.9+/-1.1% of the energy yield, although ingestion of glucose during exercise resulted in a higher plasma glucose concentration in hypoxia than normoxia. The contribution of carbohydrate (CHO) oxidation to the energy yield was significantly higher in hypoxia (92.0+/-2.1%) than in normoxia for both a given absolute (75.3+/-5.2%) and relative workload (78.1+/-1.8%). This greater reliance on CHO oxidation in hypoxia was entirely due to the significantly larger contribution of endogenous glucose oxidation to the energy yield: 75.9+/-1.7% versus 66.6+/-3.3 and 55.2+/-3.7% in normoxia at the same relative and absolute workload.


Subject(s)
Atmospheric Pressure , Exercise/physiology , Glucose/metabolism , Hypoxia/metabolism , Adult , Atmosphere Exposure Chambers , Blood Glucose/analysis , Calorimetry, Indirect , Carbon Isotopes , Exercise Test , Humans , Hyperventilation/physiopathology , Male , Oxidation-Reduction , Oxygen Consumption/physiology , Pulmonary Gas Exchange/physiology
10.
J Fr Ophtalmol ; 27 Spec No 2: 2S5-2S10, 2004 Sep.
Article in French | MEDLINE | ID: mdl-15314569

ABSTRACT

Most biological activities fluctuate throughout the day and contribute to a better adaptation to the organism's daily activity. During the last 30 Years, chronobiology has aimed at studying these biological rhythms, explaining most of the biological mechanisms of i) the endogenous circadian rhythmicity, ii) the neurophysiological mechanisms of the photic system that allows its external resetting, and iii) the neuroendocrine mechanisms of internal rhythm synchronization. Moreover, the description of specific biological rhythm disorders and rhythm problems at the cellular and even the molecular level have prompted the emerging fields of chronopharmacology and chronotherapeutics.


Subject(s)
Circadian Rhythm/physiology , Animals , Biological Clocks/physiology , Chronobiology Phenomena , Circadian Rhythm/radiation effects , Humans , Hydrocortisone/metabolism , Hypothalamo-Hypophyseal System/physiology , Light , Melatonin/metabolism , Melatonin/physiology , Meningoencephalitis/etiology , Meningoencephalitis/physiopathology , Photoperiod , Pineal Gland/physiology , Pituitary-Adrenal System/physiology , Retina/physiology , Sleep/physiology , Trypanosomiasis, African/complications , Trypanosomiasis, African/physiopathology
11.
J Fr Ophtalmol ; 27 Spec No 2: 2S19-2S26, 2004 Sep.
Article in French | MEDLINE | ID: mdl-15314571

ABSTRACT

Intraocular pressure (IOP) varies and depends on many factors. These variations throughout the nycthemeron (the full 24-h period of a night and a day) are the most interesting to study. With the current techniques, it is impossible to measure continuously without waking the subject. Therefore, IOP must be measured hourly over 24 h with a portable tonometer, which provides short measurements in any posture, without requiring the subjects to rise during the night. Intraocular pressure depends on a nyctohemeral rhythm and in healthy subjects is higher at night than during the day, with a nocturnal peak value (acrophase). In the same normal individual, several 24-h measurements are identical. Each individual has his own 24-h IOP pattern. In glaucoma patients, however, the 24-h IOP rhythm was shown to be reversed, with values higher during the day (a midday peak in IOP) than during the night. The time course of the nyctohemeral curve of intraocular pressure is considered to play a role in the prognosis of glaucoma and can serve to classify the type of glaucoma (POAG, NTG). Lowering IOP is still the only option that is available for treating patients with glaucoma. Variations encountered in the individual's nyctohemeral IOP pattern must be taken into consideration to provide the most effective treatment.


Subject(s)
Circadian Rhythm/physiology , Intraocular Pressure/physiology , Chronotherapy , Genetic Variation , Glaucoma/drug therapy , Glaucoma/physiopathology , Humans , Monitoring, Ambulatory/instrumentation , Ocular Hypertension/physiopathology , Posture , Reference Values , Reproducibility of Results , Sleep Apnea Syndromes/physiopathology , Tonometry, Ocular/instrumentation
12.
Exp Biol Med (Maywood) ; 228(11): 1355-62, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14681551

ABSTRACT

Animal models of Human African Trypanosomiasis (HAT) have been developed to understand the pathogenic mechanisms leading to the passage into the neurological phase, most of them referring to histological aspects but not clinical or behavioral data. Our study aimed at defining simple clinical and/or behavioral markers of the passage between the hemolymphatic phase and the meningo-encephalitic stage of the disease. Sprague-Dawley rats (n=24) were infected with Trypanosoma brucei brucei AnTat 1.1E. Food intake and body weight were measured daily from the day of infection until death. Hematocrit was measured twice a week. Behavioral disturbances were evaluated through an Open-field test. A sudden weight loss occurred on the twelfth day after infection, due to a significant drop of food intake starting two days before. The rats developed an anemic state shown by the hematocrit measurements. The Open-field test showed them to be less active and reactive as soon as the second week after infestation. A complementary histological study observed trypanosomes and inflammatory cells in the choroid plexus at the same period. These results are in favor of central nervous system functional disturbances. The observed weight loss is discussed as being a parameter of the entry in the meningo-encephalitic phase. The rat model reproduces neurological symptoms observed in the human disease and may prove to be useful for further neurohistological and therapeutic studies.


Subject(s)
Trypanosomiasis, African/etiology , Animals , Body Weight , Disease Models, Animal , Eating , Hematocrit , Humans , Male , Motor Activity , Rats , Rats, Sprague-Dawley , Trypanosomiasis, African/physiopathology , Trypanosomiasis, African/psychology
13.
Can J Physiol Pharmacol ; 81(10): 959-65, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14608413

ABSTRACT

The glutamate NMDA receptor has been suggested to be involved in thermoregulation. To further analyse its role, the thermoregulatory responses of rats treated with 0.5 mg.kg-1 of dizocilpine (MK801) were compared with those of control rats treated only with the same volume of saline during a 180-min exposure at one of the six different ambient temperatures, ranging from cold to heat. Colonic temperature (Tco) and tail skin temperature (Ttail) were measured throughout using Cu-Ct thermocouples. In the cold (2.4 and 12.3 degrees C), Tco decreased either sharply (MK801) or progressively (saline), reaching the same final value (2.4 degrees C) or a lower value in the MK801-treated rats (12.3 degrees C). At the same time, Ttail decreased in both groups. In the cool environment (20.7 degrees C), Tco and Ttail decreased in both groups, with lower final values in MK801-treated rats. At thermoneutrality (28.8 degrees C), the MK801-induced hyperthermia remained steady, while Ttail increased in both groups. In the heat (34.6 and 36.2 degrees C), Tco and Ttail increased in both groups, with higher final values in MK801-treated rats. Moreover, at 36.2 degrees C, only MK801-treated rats exhibited heatstroke. It is thus suggested that MK801-induced inhibition of NMDA receptors impairs thermoregulation, especially in the heat.


Subject(s)
Body Temperature Regulation/physiology , Cold Temperature , Dizocilpine Maleate/pharmacology , Hot Temperature , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Animals , History, Ancient , Male , Motor Activity/drug effects , Rats , Rats, Sprague-Dawley
14.
Med Trop (Mars) ; 63(3): 223-7, 2003.
Article in French | MEDLINE | ID: mdl-14579455

ABSTRACT

Has research on sleeping sickness, i.e., human African trypanosomiasis (HAT), been forgotten? To get an idea on funding, we consulted the Medline bibliographic database for the last 14 years. The number of publications on HAT was stagnant over the study period. By comparison there was a steady increase in the number of publications dealing with malaria. These findings suggest that interest in HAT research waned in favor of other endemics even though government or other funding agencies continued to finance research networks. To illustrate this situation, we present the funding and findings of our multidisciplinary working group in a wide range of domains including sleep, endocrine rhythms, identification of biological markers, research on physiopathologic mechanisms of the host-pathogen relationship, and development on new medications. Over the last 14 years, a total of 1 million Euros was spent to produce 68 publications on Medline, i.e., roughly 15000 [symbol: see text] per publication.


Subject(s)
Biomedical Research/trends , Trypanosomiasis, African , Disease Outbreaks , Financing, Government , Humans , Interprofessional Relations , Trypanosomiasis, African/physiopathology , Trypanosomiasis, African/therapy
15.
Neurosci Lett ; 316(1): 45-9, 2001 Dec 04.
Article in English | MEDLINE | ID: mdl-11720775

ABSTRACT

Vascular and immunological mechanisms are both likely to be involved in heatstroke, this condition being preceded by a decrease in cerebral blood flow and an increase in brain cytokine concentrations. As the two mechanisms involve a nitridergic step, we analysed their respective role in heat tolerance by exposing vigil rats to heat after treatment with nitric oxide synthases (NOS) antagonists: non-specific inhibitors N(omega)-nitro-L-arginine (LNA) and N-nitro-L-arginine-methyl-ester (L-NAME); 7-nitroindazol (neuronal NOS inhibitor) and aminoguanidine (AG) (inducible NOS inhibitor). Heat exposure was interrupted when clinical signs occurred or when colonic temperature reached 43 degrees C. LNA and L-NAME dramatically reduced heat tolerance, while AG did not modify it. These results suggest the involvement of constitutive NOS in heat tolerance. Inducible NOS does not seem to be involved in the occurrence of heatstroke.


Subject(s)
Body Temperature Regulation/drug effects , Enzyme Inhibitors/pharmacology , Hot Temperature , Nitric Oxide Synthase/antagonists & inhibitors , Animals , Body Temperature Regulation/physiology , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Male , Nitric Oxide Synthase/metabolism , Nitric Oxide Synthase Type II , Nitric Oxide Synthase Type III , Rats , Rats, Sprague-Dawley
16.
Eur J Pharmacol ; 426(3): 179-83, 2001 Aug 31.
Article in English | MEDLINE | ID: mdl-11527542

ABSTRACT

Sulfhydryl-reducing agents, such as dithiothreitol, modulate glutamate N-methyl-D-aspartate (NMDA) receptors. Since these receptors are involved in thermoregulatory processes, we studied the effects of their positive modulation, through a dithiothreitol-induced reduction of the receptor redox site, on thermoregulation in rats maintained at an ambient temperature of 20-22 degrees C. Given intraperitoneally at the dose of 25 and 50 mg x kg(-1), dithiothreitol induced dose-dependent hypothermia. The prior administration of 0.5 mg x kg(-1) of (+/-)-dizocilpine maleate (MK801), a non-competitive glutamate NMDA receptor antagonist, blocked most of the dithiothreitol-induced hypothermia. MK801 given alone was followed by slight transient hyperthermia. This confirms the involvement of NMDA receptors in thermoregulation and suggests that they might be under redox modulation.


Subject(s)
Body Temperature/drug effects , Dithiothreitol/pharmacology , Receptors, N-Methyl-D-Aspartate/physiology , Animals , Dizocilpine Maleate/pharmacology , Dose-Response Relationship, Drug , Excitatory Amino Acid Antagonists/pharmacology , Hypothermia, Induced , Injections, Intraperitoneal , Male , Rats , Rats, Sprague-Dawley , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Time Factors
17.
Sleep Med Rev ; 5(2): 139-153, 2001 Apr.
Article in English | MEDLINE | ID: mdl-12531051

ABSTRACT

Sleeping sickness, once under control, is a re-emergent endemic parasitic disease in intertropical Africa. Its originality resides in its duality. Two trypanosome groups (Trypanososma brucei gambiense vs.rhodesiense ) are transmitted to humans by tsetse flies from two geographical areas (Western and Central Africa humid forest vs. Eastern Africa arboreous savannah), provoking a slowly or a rapidly evolutive disease. The two stage (haemolymphatic vs. neurological invasion) pathogenic evolution leads to the duality of the immune response, depending on the host-parasite inter-relation differences in the blood and the brain. In the blood, the immune processes involved are both specific (anti-variant surface glycoprotein (VSG) antibodies) and non-specific (complement-mediated lysis, opsonification-facilitated phagocytosis and antibody dependent cell-mediated cytotoxicity). Although macrophages are activated in the blood and infiltrate the brain, nitric oxide decreases in the blood and increases in the brain, with a breakage in the blood-brain barrier, leading to brain lesions through the production of deleterious molecules. Prophylactic means are affected by the duality of pathogenic processes. This finally leads to a two stage disease (haemolymphatic vs. neurological) with two different therapeutic strategies. The sleep-wake cycle and other biological rhythms are also marked by the disappearance of circadian rhythmicity demasking basic ultradian activities and relationships, such as the interdependence of endocrine profiles and the sleep-wake alternation. 2001 Harcourt Publishers Ltd

18.
Med Trop (Mars) ; 61(4-5): 328-39, 2001.
Article in French | MEDLINE | ID: mdl-11803823

ABSTRACT

At the meningoencephalitis stage, human African trypanosomiasis (HAT), sleeping sickness, causes dysregulation of the circadian rhythm of the sleep/wake cycle, rather than hypersomnia. In bedridden patients, total sleep time does not exceed 9 hours. The change in the 24-hour distribution of sleep and wakefulness is proportional to severity of clinical symptoms and laboratory abnormalities. The internal structure of sleep is also altered. All patients present sleep onset rapid eye movement periods (SOREMP), i.e., several sleep episodes beginning with rapid eye movement (REM) sleep. In mild cases, treatment with melarsoprol reverses circadian dysregulation, and SOREMP either decrease in number or disappear. Other circadian disturbances may be observed in HAT. These may include circadian dysrhythmia of hormonal secretions, but the relationship between hormonal pulses and sleep/wake states is preserved. The circadian rhythm of secretion of prolactin, renin, growth hormone and cortisol disappears in severe cases, but persists in mild ones. The amplitude and mean 24-hour value of plasma melatonin are normal with nocturnal peaks and no diurnal secretion. However, peak melatonin secretion occurs 2 hours earlier than in healthy African controls. In conclusion, HAT-induced dysregulation of circadian rhythm is proportional to disease severity. Presence of SOREMP and precocity of peak melatonin secretion support disturbance of the serotoninergic network rather than direct action on the biological clock.


Subject(s)
Circadian Rhythm , Trypanosomiasis, African/physiopathology , Human Growth Hormone/blood , Humans , Hydrocortisone/blood , Melatonin/blood , Prolactin/blood , Renin/blood , Sleep Wake Disorders/parasitology , Sleep, REM , Wakefulness
19.
Acta Biotheor ; 48(3-4): 259-72, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11291944

ABSTRACT

This work presents an hydrodynamical model of heat stroke, which is a physiopathological state of stress, due to an exposure of animals to an ambient temperature of approximatively 40 degrees C during two hours. The evolution of body temperature during this stress process is characterised by three phases. A first phase of increase is followed by a plateau which occurs before a second phase of increase which can be lethal. The model is based on the analogy of a boat progressively caught in a whirlpool. The evolution of the degree of freedom lost by the boat is mathematically analysed and this study leads to the same three phases. The theoretical curves calculated during this study are well in agreement with the experimental curves obtained with animals. This analogy is compared to a previous one which has been made during another experiment with animals constrained by chemical intoxications. It seems that stress can be considered as a vital vorticity and that hydrodynamic models are powerful tools in understanding this physiopathological state.


Subject(s)
Body Temperature Regulation/physiology , Disease Models, Animal , Heat Exhaustion/physiopathology , Animal Testing Alternatives , Animals , Humans , Models, Theoretical , Stress, Physiological/physiopathology
20.
Eur J Appl Physiol Occup Physiol ; 79(5): 397-403, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10208247

ABSTRACT

To determine whether or not acute hypobaric hypoxia alters the rate of water absorption from a carbohydrate beverage ingested during exercise, six men cycled for 80 min on three randomly assigned different occasions. In one trial, exercise was performed in hypoxia (barometric pressure, P(B) = 594 hPa, altitude 4,400 m) at an exercise intensity selected to elicit 75% of the individual's maximal oxygen uptake (VO2max) previously determined in such conditions. In the two other experiments, the subjects cycled in normoxia (P(B) = 992 hPa) at the same absolute and the same relative intensities as in hypoxia, which corresponded to 55% and 75%, respectively, of their VO2max determined in normoxia. The subjects consumed 400 ml of a 12.5% glucose beverage just prior to exercise, and 250 ml of the same drink at 20, 40 and 60 min from the beginning of exercise. The first drink contained 20 ml of deuterium oxide to serve as a tracer for the entry of water into body fluids. The heart rate (HR) during exercise was higher in hypoxia than in normoxia at the same absolute exercise intensity, whereas it was similar to HR measured in normoxia at the same relative exercise intensity. Both in normoxia and hypoxia, plasma noradrenaline concentrations were related to the relative exercise intensity up to 40 min of exercise. Beyond that duration, when exercise was performed at the highest absolute power in normoxia, the noradrenaline response was higher than in hypoxia at the same relative exercise intensity. No significant differences were observed among experimental conditions, either in temporal profiles of plasma D accumulation or in elimination of water ingested in sweat. Conversely, elimination in urine of the water ingested appeared to be related to the severity of exercise, either high absolute power or the same relative power combined with hypoxia. We concluded that water absorption into blood after drinking a 12.5% glucose beverage is not altered during cycling exercise in acute hypobaric hypoxia. It is suggested that the elimination of water ingested in sweat and urine may be dependent on local circulatory adjustments during exercise.


Subject(s)
Altitude , Atmospheric Pressure , Deuterium , Exercise , Hypoxia , Water/metabolism , Absorption , Beverages , Body Fluids/chemistry , Deuterium/analysis , Dietary Carbohydrates/administration & dosage , Heart Rate , Humans , Kinetics , Male , Norepinephrine/blood , Oxygen Consumption , Plasma Volume , Sweat , Urine
SELECTION OF CITATIONS
SEARCH DETAIL
...