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1.
BMC Cancer ; 22(1): 1219, 2022 Nov 25.
Article de Anglais | MEDLINE | ID: mdl-36434607

RÉSUMÉ

BACKGROUND: Previous studies have observed an increased incidence of Cetuximab-induced hypersensitivity infusion reactions (CI-IRs) in the southeastern states of the USA. Tick's bites were suspected of generating cross-reactions between cetuximab and alpha-gal. This study aims was to describe the incidence and associated risk factors of CI-IRs, in the French areas chosen according to their Lyme disease incidence. PATIENTS AND METHODS: A retrospective chart review was conducted on patients that received cetuximab infusion from January 2010 to June 2019 in 4 French areas with different Lyme disease incidence rates. RESULTS: Of 1392 patients, 117 (8.4%) experienced a CI-IR, including 68 severe (grade 3 or 4) reactions (4.9%). This CI-IR incidence was significantly higher in the Lyme disease high-risk area than in the other areas (13.2% versus 7.1%, 8.1% and 6.4%; P = 0.016). Sex (P = 0.53), premedication (P = 0.91), primary cancer location (P = 0.46) and chemotherapy regimen type (P = 0.78) had no impact on CI-IR incidence in the overall population. In the head and neck squamous cell carcinoma (HNSCC) patient subgroup, CI-IRs were significantly more frequent in the high-risk area (16.4% versus 6.7%, 7.1% and 7.0%; P = 0.0015). CONCLUSION: This study suggests that patients treated in the French area with the highest incidence of Lyme disease are at a higher risk of CI-IRs.


Sujet(s)
Hypersensibilité médicamenteuse , Tumeurs de la tête et du cou , Maladie de Lyme , Humains , Cétuximab/effets indésirables , Incidence , Études rétrospectives , Hypersensibilité médicamenteuse/épidémiologie , Hypersensibilité médicamenteuse/étiologie , Perfusions veineuses , Tumeurs de la tête et du cou/complications , Maladie de Lyme/traitement médicamenteux , Maladie de Lyme/épidémiologie , Maladie de Lyme/complications
2.
Dig Liver Dis ; 52(6): 658-667, 2020 06.
Article de Anglais | MEDLINE | ID: mdl-32362489

RÉSUMÉ

BACKGROUND: The effect of treatment delay on survival in pancreatic ductal adenocarcinoma (PDAC) remains unclear. AIMS: This study aimed to assess the prognostic impact of time to diagnosis and chemotherapy in advanced PDAC and factors influencing the time intervals. METHODS: advanced PDAC patients receiving chemotherapy in five centers in the decade 2007-2016 were included. Key time points during care pathway from clinical presentation to beginning of chemotherapy were retrospectively collected. Multivariate Cox proportional hazard model was performed. RESULTS: A total of 409 patients were included (mean age 66.1 ± 10.3 years; 250 metastatic (61%); 139 received FOLFIRINOX chemotherapy (34%). The median overall survival (OS) was 7.2 months. The median times from first symptoms and from first specialist visit to the beginning of chemotherapy were respectively 100 days and 47 days. None of time intervals was significantly associated with OS. Significant prognostic factors were FOLFIRINOX chemotherapy (HR 0.6 [0.5-0.8]; P < 0.001), metastasis (HR 1.6 [1.3-2.0]; P = 0.001), WHO PS ≥ 2 (HR 1.6 [1.2-2.1]; P < 0.001) and acute pancreatitis as first symptom (HR 2.9 [1.7-4.9]; P < 0.001). Jaundice shortened time to diagnosis (P < 0.001). Acute pancreatitis (P < 0.001) and diabetes (P = 0.01) increased time to treatment. CONCLUSION: Wait times from clinical presentation to beginning of chemotherapy do not influence survival in advanced PDAC.


Sujet(s)
Adénocarcinome/traitement médicamenteux , Adénocarcinome/mortalité , Tumeurs du pancréas/traitement médicamenteux , Tumeurs du pancréas/mortalité , Délai jusqu'au traitement , Adénocarcinome/anatomopathologie , Sujet âgé , Protocoles de polychimiothérapie antinéoplasique/usage thérapeutique , Diabète/physiopathologie , Femelle , Fluorouracil/usage thérapeutique , France/épidémiologie , Humains , Irinotécan/usage thérapeutique , Leucovorine/usage thérapeutique , Mâle , Adulte d'âge moyen , Analyse multifactorielle , Oxaliplatine/usage thérapeutique , Tumeurs du pancréas/anatomopathologie , Pancréatite/physiopathologie , Pronostic , Modèles des risques proportionnels , Études rétrospectives
3.
J Gynecol Obstet Hum Reprod ; 47(2): 35-38, 2018 Feb.
Article de Anglais | MEDLINE | ID: mdl-29208503

RÉSUMÉ

OBJECTIVE: To evaluate maternal tolerance to digoxin, used alone or associated to other antiarrhythmic drugs in the management of fetal tachycardia. PATIENTS AND METHODS: This retrospective study was conducted at Rouen University Hospital between January 2009 and July 2016. All women who have received a treatment by either digoxin alone or associated with another antiarrhythmic drug for fetal tachycardia were included in the study. Maternal cardiac and extracardiac adverse effects were reported and comparisons between electrocardiograms before and during treatment with digoxin alone were performed. RESULTS: Eighteen women were treated by digoxin, either alone or associated with another antiarrhythmic (sotalol, flecainide or amiodarone). During treatment, digoxin overdosing (>2ng/mL) was observed in 11 women (61%), among which 4 women had toxic levels of digoxinemia (>3ng/mL) that was symptomatic in 3 women. Cardiac complications such as sinus bradycardia, first-degree auriculo-ventricular block and Mobitz I second-degree auriculo-ventricular block were reported in four women (18.2%). Extracardiac side effects i.e. neurosensorial or digestive were diagnosed in 35.3% of women. The parameters of the electrocardiogram were not altered before and after treatment with digoxin alone. CONCLUSION: Antiarrhythmics can cause maternal cardiac complications and extracardiac side effects that can sometimes be severe but rapidly reversible upon treatment arrest.


Sujet(s)
Antiarythmiques/effets indésirables , Digoxine/effets indésirables , Maladies foetales/traitement médicamenteux , Complications cardiovasculaires de la grossesse/induit chimiquement , Complications cardiovasculaires de la grossesse/physiopathologie , Tachycardie/traitement médicamenteux , Adulte , Digoxine/sang , Électrocardiographie , Femelle , Humains , Grossesse
4.
J Gynecol Obstet Hum Reprod ; 46(3): 297-299, 2017 Mar.
Article de Français | MEDLINE | ID: mdl-28403929

RÉSUMÉ

We report a retrospective series of 12 placentas percreta with bladder invasion and for which an expected initially multidisciplinary conservative surgical treatment associated with uterine artery embolization was programmed. Conservative surgical treatment was only performed in 7 women. Radical surgical treatment was necessary during the caesarean section and complicated by massive hemorrhage in three women and secondary in two other women for infectious diseases. Radical surgical treatment was associated with partial cystectomy complicated with urinary disorder sequelae in three women. Maternal morbidity of the placenta percreta bladder remains high despite the establishment of a multidisciplinary care protocol.


Sujet(s)
Placenta accreta/thérapie , Embolisation d'artère utérine , Adulte , Césarienne , Traitement conservateur , Cystectomie , Femelle , Humains , Hystérectomie , Hémorragie de la délivrance/étiologie , Hémorragie de la délivrance/chirurgie , Grossesse , Études rétrospectives
5.
Neurochirurgie ; 62(2): 94-9, 2016 Apr.
Article de Anglais | MEDLINE | ID: mdl-26853800

RÉSUMÉ

PURPOSE: To assess long-term neurodevelopmental outcome in children with hydrocephalus requiring neurosurgical treatment during the neonatal period. METHODS: This prospective longitudinal population-based study included 43 children with neonatal shunted hydrocephalus. The 43 children were prospectively reviewed in the presence of their parents at the outpatient clinic. Cognitive and motor outcomes were assessed respectively using different Wechsler scales according to age and Gross Motor Function Classification System (GMFCS). Postoperative MRI was routinely performed. RESULTS: The mean gestational age at birth of the 43 consecutive children with neonatal hydrocephalus (sex ratio M/F: 1.39) was 34.5±5.4 weeks of gestation. At mean follow-up of 10.4±4 years, mean total IQ was 73±27.7, with equivalent results in mean verbal and mean performance IQ. Of the 33 children with IQ evaluation, 18 presented an IQ≥85 (41.9%). Efficiency in walking without a mobility device (GMFCS≤2) was obtained in 37 children (86%). Only severity of postoperative ventricular dilation was significantly associated with unfavorable outcome (Evans index>0.37; odds ratio: 0.16, P=0.03). CONCLUSION: This information could be provided to those families concerned who often experience anxiety when multi-disciplinary management of neonatal hydrocephalus is required.


Sujet(s)
Hydrocéphalie/chirurgie , Maladies du prématuré/chirurgie , Troubles du développement neurologique/étiologie , Complications postopératoires/prévention et contrôle , Dérivation ventriculopéritonéale , Ventriculostomie , Malformations multiples , Tumeurs des ventricules cérébraux/complications , Tumeurs des ventricules cérébraux/chirurgie , Femelle , Études de suivi , Âge gestationnel , Humains , Hydrocéphalie/complications , Hydrocéphalie/imagerie diagnostique , Nouveau-né , Prématuré , Déficience intellectuelle/épidémiologie , Déficience intellectuelle/étiologie , Déficience intellectuelle/prévention et contrôle , Imagerie par résonance magnétique , Mâle , Troubles de la motricité/épidémiologie , Troubles de la motricité/étiologie , Troubles de la motricité/prévention et contrôle , Troubles du développement neurologique/épidémiologie , Troubles du développement neurologique/prévention et contrôle , Complications postopératoires/imagerie diagnostique , Complications postopératoires/épidémiologie , Complications postopératoires/étiologie , Études prospectives , Indice de gravité de la maladie , Résultat thérapeutique
6.
Ultrasound Obstet Gynecol ; 43(3): 346-52, 2014 Mar.
Article de Anglais | MEDLINE | ID: mdl-23640781

RÉSUMÉ

In order to illustrate the significance of a new anatomical finding, distortion of the interhemispheric fissure (DIHF) associated with impacted medial borders of the frontal lobes, we report a retrospective observational study of 13 fetuses in which DIHF was identified on prenatal imaging. In 10 cases there were associated anatomical anomalies, including mainly midline anomalies (syntelencephaly (n=2), lobar holoprosencephaly (n=1), Aicardi syndrome (n=2)), but also schizencephaly (n=1), cortical dysplasia (n=1) and more complex cerebral malformations (n=3), including neural tube defect in two cases. Chromosomal anomaly was identified in two cases, including 6p deletion in a case without associated central nervous system anomalies and a complex mosaicism in one of the cases with syntelencephaly. In two cases, the finding was apparently isolated on both pre- and postnatal imaging, and the children were doing well at follow-up, aged 4 and 5 years. The presence of DIHF on prenatal imaging may help in the diagnosis of cerebral anomalies, especially those involving the midline. If DIHF is apparently isolated on prenatal ultrasound, magnetic resonance imaging is recommended for careful analysis of gyration and midline, especially optic and olfactory structures. Karyotyping is also recommended.


Sujet(s)
Cortex cérébral/malformations , Cortex cérébral/imagerie diagnostique , Imagerie par résonance magnétique , Malformations corticales/imagerie diagnostique , Échographie prénatale , Femelle , Études de suivi , Âge gestationnel , Humains , Nouveau-né , Malformations corticales/embryologie , Malformations corticales/anatomopathologie , Valeur prédictive des tests , Grossesse , Études rétrospectives
7.
J Radiol ; 90(1 Pt 1): 11-9, 2009 Jan.
Article de Français | MEDLINE | ID: mdl-19182709

RÉSUMÉ

MR Urography (MRU) provides both morphologic and functional information without radiation exposure. It enables the assessment of split renal function, excretion, and quantification of obstruction. MRU is thus complementary to ultrasonography in the assessment of pre- and post-natal obstructive uropathies in children. If available, MRU should be definitely preferred to intravenous urography.


Sujet(s)
Hydronéphrose/diagnostic , Angiographie par résonance magnétique/méthodes , Imagerie par résonance magnétique/méthodes , Urographie/méthodes , Maladies urologiques/diagnostic , Adulte , Facteurs âges , Poids , Enfant d'âge préscolaire , Produits de contraste/administration et posologie , Diurétiques/administration et posologie , Femelle , Furosémide/administration et posologie , Acide gadopentétique/administration et posologie , Humains , Nourrisson , Maladies du rein/diagnostic , Mâle , Facteurs sexuels , Jeune adulte
8.
Int J Oral Maxillofac Surg ; 35(9): 850-5, 2006 Sep.
Article de Anglais | MEDLINE | ID: mdl-16697145

RÉSUMÉ

This research focuses on the effects of radiotherapy on bone remodelling around mandibular implants in dogs. After bilateral extraction of the mandibular premolars and first 2 molars, each of 11 beagles received 8 mandibular implants. Four animals were irradiated 4 weeks after implantation and 4 others 8 weeks before implantation; the remaining 3 did not receive radiotherapy. Irradiation consisted of 10 daily fractions of 4.3Gy (60)Co. Fluorochromes were given at implantation and irradiation to allow the measurement of bone apposition. The dogs were killed 6 months after implantation. Each hemi-mandible was processed according to bone-specific histological techniques. New bone formation was visible around 85 of the 88 implants. Stimulated mandibular remodelling was attested in both irradiated groups by increased porosity and numerous labelled osteons. Resorption was more pronounced in the group irradiated after implantation, but osteon formation appeared unvarying. Osseointegration was thus shown to be compatible with bone irradiation as bone turnover activities were maintained throughout the experiment. As the apposition stage of the remodelling cycle appears crucial to achieve optimal osseointegration, its normal completion should be taken into account in clinical practice by respecting a 6-month period between irradiation and implantation.


Sujet(s)
Remodelage osseux/effets des radiations , Pose d'implant dentaire endo-osseux , Implants dentaires , Mandibule/effets des radiations , Ostéo-intégration/effets des radiations , Animaux , Chiens , Mâle , Mandibule/chirurgie , Répartition aléatoire , Facteurs temps
9.
Anal Biochem ; 249(1): 29-36, 1997 Jun 15.
Article de Anglais | MEDLINE | ID: mdl-9193705

RÉSUMÉ

STAT (signal transducers and activators of transcription) is a class of transcription factors that are activated upon cytokine or growth factor binding to cell surface receptors. Activated STAT proteins dimerize, translocate into the nucleus, and activate transcription, leading to various immune responses. The inhibition of STAT binding to cell receptors might provide a means to modulate these immune responses. We developed a high-throughput biochemical assay to measure the interaction between an interferon-gamma receptor-derived phosphotyrosine-containing peptide and STAT1, using fluorescence polarization as the detection method. This assay can be used to screen for small molecules capable of disrupting receptor-STAT interactions.


Sujet(s)
Protéines de liaison à l'ADN/composition chimique , Polarisation de fluorescence , Transduction du signal/physiologie , Transactivateurs/composition chimique , Fixation compétitive , Modèles logistiques , Oligopeptides/composition chimique , Phosphotyrosine/composition chimique , Liaison aux protéines , Facteur de transcription STAT-1
10.
Anal Biochem ; 244(2): 340-6, 1997 Jan 15.
Article de Anglais | MEDLINE | ID: mdl-9025951

RÉSUMÉ

A chemiluminescent protein kinase assay using biotinylated substrate peptides captured on a streptavidin-coated microtiter plate and monoclonal antibodies to detect their phosphorylation is described. Assay conditions were optimized and validated for sensitive measurement of protein kinase A, protein kinase C, Ca2+/calmodulin-dependent protein kinase II (CAM-KII), receptor interacting protein, and src activities. The newly developed chemiluminescent assay has several advantages over currently used radioactive or colorimetric methods. It is highly sensitive at low enzyme and substrate concentrations and high, close to physiological ATP levels. It is fast, simple to perform and amenable to automation and high-throughput drug screening. The assay is also robust, exhibiting minimum interference from solvents and test substances from various sources. Overall, among the presently available methods for the detection of protein kinase activity, chemiluminescence was found to provide the highest sensitivity under conditions most closely mimicking the intracellular environment. This assay is expected to be useful in both academic and industrial laboratories, especially in identifying novel classes of protein kinase inhibitors.


Sujet(s)
Cyclic AMP-Dependent Protein Kinases/analyse , Mesures de luminescence , Adénosine triphosphate/métabolisme , Animaux , Apoptose , Colorimétrie , Test ELISA , Protéine gliofibrillaire acide/analyse , Souris , Phosphorylation , Protéines/analyse , Receptor-Interacting Protein Serine-Threonine Kinases , src-Family kinases/analyse
11.
Article de Anglais | MEDLINE | ID: mdl-9007457

RÉSUMÉ

Strenuous exercise may be associated with immune suppression. However, the underlying mechanism is not known. A decrease in the plasma level of glutamine, which is utilised at a high rate by cells of the immune system, and an increase in the plasma level of some cytokines may impair immune functions such as lymphocyte proliferation after prolonged, exhaustive exercise. In two separate studies of the Brussels marathon, using similar protocols, the time course of the changes in the plasma concentrations of some amino acids (glutamine, glutamate, alanine, tryptophan and branched chain amino acids), acute phase proteins and cytokines (interleukins IL-1 alpha, IL-2, IL-6, tumour necrosis factor type a) was measured in male athletes. The numbers of circulating leucocytes and lymphocytes were also measured. Amino acid and cytokine concentrations have not previously been measured concomitantly in marathon runners; the measurement of some of these parameters the morning after the marathon (16 h) is novel. Another novel feature is the provision of glutamine versus placebo to marathon runners participating in the second study. In both studies the plasma concentrations of glutamine, alanine and branched chain amino acids were decreased immediately after and 1 h after the marathon. Plasma concentrations of all amino acids returned to pre-exercise levels by 16 h after exercise. The plasma concentration of the complement anaphylotoxin C5a increased to abnormal levels after the marathon, presumably due to tissue damage activating the complement system. There was also an increase in plasma C-reactive protein 16 h after the marathon. The plasma levels of IL-1 alpha were unaffected by the exercise, while that of IL-2 was increased 16 h after exercise. Plasma IL-6 was increased markedly (approximately 45-fold) immediately after and at 1 h after exercise. Neopterine, a macrophage activation marker, was significantly increased post-exercise. There was a marked leucocytosis immediately after the marathon, which returned to normal 16 h later. At the same time there was a decrease in the number of T-lymphocytes, which was further reduced within 1 h to below pre-exercise levels. Glutamine supplementation, as administered in the second study, did not appear to have an effect upon lymphocyte distribution.


Sujet(s)
Réaction inflammatoire aigüe , Exercice physique/physiologie , Glutamine/administration et posologie , Endurance physique/physiologie , Course à pied , Protéine de la phase aigüe/métabolisme , Adulte , Acides aminés/sang , Protéine C-réactive/métabolisme , Complément C5a/métabolisme , Cytokines/sang , Humains , Interleukine-1/sang , Interleukine-2/sang , Cinétique , Numération des leucocytes , Mâle
12.
Immunity ; 2(6): 689-97, 1995 Jun.
Article de Anglais | MEDLINE | ID: mdl-7796300

RÉSUMÉ

Latent and activated forms of Stat1 and Stat6 have been expressed and purified, enabling biochemical experiments relating to their functional activities. Stat1 bound to a phosphotyrosine peptide derived from the IFN gamma receptor with a KD of 50 nM, whereas Stat6 bound to an IL-4 receptor peptide with a KD of 300 nM. Stat-receptor peptide interactions were specific and dependent upon tyrosine phosphorylation. Activated forms of Stat1 and Stat6 were used to select their optimal DNA binding sites. Stat1 selected a recognition site having dyad half-sites separated by 3 bp. Stat6 selected a recognition site composed of the same dyad half-sites, yet separated by 4 bp. Chimeric Stat1-Stat6 recombinants were expressed, purified, and assayed for receptor coupling and DNA binding specificity. Such studies led to the identification of polypeptide domains that specify these activities. These observations provide a framework for understanding how different cytokines elicit distinctive patterns of gene expression.


Sujet(s)
Protéines de liaison à l'ADN/métabolisme , Phosphopeptides/métabolisme , Transactivateurs/métabolisme , Séquence d'acides aminés , Séquence nucléotidique , Cellules cultivées , Protéines de liaison à l'ADN/analyse , Protéines de liaison à l'ADN/composition chimique , Polarisation de fluorescence/méthodes , Humains , Données de séquences moléculaires , Liaison aux protéines/physiologie , Protéines de fusion recombinantes/composition chimique , Facteur de transcription STAT-1 , Facteur de transcription STAT-6 , Transactivateurs/composition chimique
13.
Science ; 265(5179): 1701-6, 1994 Sep 16.
Article de Anglais | MEDLINE | ID: mdl-8085155

RÉSUMÉ

Interleukin-4 (IL-4) is an immunomodulatory cytokine secreted by activated T lymphocytes, basophils, and mast cells. It plays an important role in modulating the balance of T helper (Th) cell subsets, favoring expansion of the Th2 lineage relative to Th1. Imbalance of these T lymphocyte subsets has been implicated in immunological diseases including allergy, inflammation, and autoimmune disease. IL-4 may mediate its biological effects, at least in part, by activating a tyrosine-phosphorylated DNA binding protein. This protein has now been purified and its encoding gene cloned. Examination of the primary amino acid sequence of this protein indicates that it is a member of the signal transducers and activators of transcription (Stat) family of DNA binding proteins, hereby designated IL-4 Stat. Study of the inhibitory activities of phosphotyrosine-containing peptides derived from the intracellular domain of the IL-4 receptor provided evidence for direct coupling of receptor and transcription factor during the IL-4 Stat activation cycle. Such observations indicate that IL-4 Stat has the same functional domain for both receptor coupling and dimerization.


Sujet(s)
Protéines de liaison à l'ADN/métabolisme , Interleukine-4/pharmacologie , Récepteur mitogène/métabolisme , Transactivateurs/métabolisme , Facteurs de transcription/métabolisme , Séquence d'acides aminés , Séquence nucléotidique , Lignée cellulaire , Clonage moléculaire , Réactifs réticulants , ADN/métabolisme , Protéines de liaison à l'ADN/composition chimique , Protéines de liaison à l'ADN/génétique , Protéines de liaison à l'ADN/isolement et purification , Humains , Sous-unité alpha du récepteur à l'interleukine-4 , Modèles biologiques , Données de séquences moléculaires , Monocytes/métabolisme , Phosphopeptides/métabolisme , Phosphopeptides/pharmacologie , Phosphorylation , Polymères , Récepteurs de surface cellulaire , Récepteurs à l'interleukine-4 , Facteur de transcription STAT-6 , Transactivateurs/composition chimique , Transactivateurs/génétique , Transactivateurs/isolement et purification , Facteurs de transcription/composition chimique , Facteurs de transcription/génétique
14.
Arch Gen Psychiatry ; 51(8): 616-24, 1994 Aug.
Article de Anglais | MEDLINE | ID: mdl-8042910

RÉSUMÉ

OBJECTIVE: To characterize sleep and the 24-hour profiles of cortisol, prolactin (PRL), and growth hormone (GH) secretion in mania. METHODS: Blood was sampled at 15-minute intervals, and sleep was polygraphically recorded in eight unmedicated male patients with pure mania and the results compared with those from a group of 14 healthy age-matched controls. The circadian, sleep-related, and pulsatile hormonal variations were quantitatively characterized using specifically designed computer algorithms. RESULTS: The manic state was associated with alterations of corticotropic activity and circadian rhythmicity partially overlapping those previously observed in acute endogenous depression, consisting of an elevation of nocturnal cortisol levels and an early timing of the nadir of the circadian variation. Sleep onset was delayed and the sleep period was reduced. A trend for short rapid eye movement latencies was apparent in the adult patients. Both the amount and the temporal organization of PRL and GH secretion were normal. CONCLUSION: The manic state seems to be characterized by similar but less severe neuroendocrine and circadian abnormalities, compared with major depression.


Sujet(s)
Trouble bipolaire/sang , Rythme circadien , Hormone de croissance/sang , Hydrocortisone/sang , Prolactine/sang , Maladie aigüe , Adolescent , Adulte , Facteurs âges , Trouble dépressif/sang , Humains , Mâle , Adulte d'âge moyen , Polysomnographie , Récidive , Sommeil/physiologie , Sommeil paradoxal/physiologie
16.
Article de Anglais | MEDLINE | ID: mdl-1563370

RÉSUMÉ

Classically, cold induced plasma volume reduction is explained by an increased diuresis which is generated by an inhibition of antidiuretic hormone release. However, most of the haemoconcentration appears to be reversible during rewarming. This observation weakens the former statement. The aim of this study was to clarify the mechanisms involved in the reversal of the cold induced haemoconcentration. Six young males, resting in a dorsal reclining position, were exposed successively to a thermoneutral environment (30 min), a cold environment (1 degrees C; cold) or thermoneutrality (control) for 120 min, and during a 60-min recovery period in thermoneutral conditions. During cold stress, a reduction of 15% (i.e. 510 ml) of the plasma volume was observed, and osmolality was unchanged. After the 60-min recovery under thermoneutral conditions, plasma volume variation between the Cold and the Control experiments was reduced and reached 3% (i.e. 100 ml). This volume equalled the increased amount of urine production observed during the cold stress experiment. Haemoconcentration cannot be explained by increased urinary water loss (+/- 100 ml) alone. Therefore a transient shift of plasma water from vascular to interstitial spaces, due to an increase of blood pressure, could be involved in the reduction of plasma volume.


Sujet(s)
Basse température , Volume plasmatique/physiologie , Adulte , Température du corps , Eau corporelle/métabolisme , Diurèse/physiologie , Humains , Mâle , Concentration osmolaire , Consommation d'oxygène , Vasopressines/sang
17.
J Biol Chem ; 266(29): 19851-7, 1991 Oct 15.
Article de Anglais | MEDLINE | ID: mdl-1717472

RÉSUMÉ

Antimicrobial peptides are widely distributed in nature and appear to play a role in the host defense of plants and animals. In this study we report the existence of antimicrobial peptides in the stomach of the vertebrate Xenopus laevis, an animal previously shown to store high concentrations of antimicrobial peptides in its skin. Antimicrobial activity was detected in extracts of X. laevis stomach tissue and nine antimicrobial peptides were then purified. A novel 24-amino acid peptide, designated PGQ, was isolated from these extracts, and has the following amino acid sequence: GVLSNVIGYLKKLGTGALNAVLKQ. PGQ is relatively basic and has the potential to form an amphipathic alpha-helix. The other peptides isolated are members of the magainin family of antimicrobial peptides, and include magainins I and II, PGLa, xenopsin precursor fragment, and four caerulein precursor fragments. None of these peptides had been previously identified in tissues other than the skin. The purification of the peptides from stomach extracts and subsequent protein sequence analysis reveals that the peptides have undergone the same processing as their dermal counterparts, and that they are stored in their processed forms. Northern blot analysis indicates that the magainin family of peptides are synthesized in the stomach, and immunohistochemical studies demonstrate that magainin is stored in a novel granular multinucleated cell in the gastric mucosa of Xenopus. This study demonstrates that the magainin family of antimicrobial peptides is found in the gastrointestinal system of X. laevis and offers an opportunity to further define the physiological role of these defense peptides.


Sujet(s)
Anti-infectieux/isolement et purification , Peptides/pharmacologie , Estomac/composition chimique , Séquence d'acides aminés , Animaux , Technique de Northern , Chromatographie en phase liquide à haute performance , Électrophorèse , Données de séquences moléculaires , ARN/analyse , Peau/composition chimique , Xenopus laevis
18.
Proc Natl Acad Sci U S A ; 88(9): 3952-6, 1991 May 01.
Article de Anglais | MEDLINE | ID: mdl-2023943

RÉSUMÉ

Extracts of the bovine tracheal mucosa have an abundant peptide with potent antimicrobial activity. The 38-amino acid peptide, which we have named tracheal antimicrobial peptide (TAP), was isolated by a sequential use of size-exclusion, ion-exchange, and reverse-phase chromatographic fractionations using antimicrobial activity as a functional assay. The yield was approximately 2 micrograms/g of wet mucosa. The complete peptide sequence was determined by a combination of peptide and cDNA analysis. The amino acid sequence of TAP is H-Asn-Pro-Val-Ser-Cys-Val-Arg-Asn-Lys-Gly-Ile-Cys-Val-Pro-Ile-Arg-Cys-Pr o- Gly-Ser-Met-Lys-Gln-Ile-Gly-Thr-Cys-Val-Gly-Arg-Ala-Val-Lys-Cys-Cys-Arg- Lys-Lys - OH. Mass spectral analysis of the isolated peptide was consistent with this sequence and indicated the participation of six cysteine residues in the formation of intramolecular disulfide bonds. The size, basic charge, and presence of three intramolecular disulfide bonds is similar to, but clearly distinct from, the defensins, a well-characterized class of antimicrobial peptides from mammalian circulating phagocytic cells. The putative TAP precursor is predicted to be relatively small (64 amino acids), and the mature peptide resides at the extreme carboxyl terminus and is bracketed by a short putative propeptide region and an inframe stop codon. The mRNA encoding this peptide is more abundant in the respiratory mucosa than in whole lung tissue. The purified peptide had antibacterial activity in vitro against Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, and Pseudomonas aeruginosa. In addition, the peptide was active against Candida albicans, indicating a broad spectrum of activity. This peptide appears to be, based on structure and activity, a member of a group of cysteine-rich, cationic, antimicrobial peptides found in animals, insects, and plants. The isolation of TAP from the mammalian respiratory mucosa may provide insight into our understanding of host defense of this vital tissue.


Sujet(s)
Peptides antimicrobiens cationiques , Peptides/génétique , Peptides/isolement et purification , Trachée/composition chimique , Séquence d'acides aminés , Bactéries/effets des médicaments et des substances chimiques , Séquence nucléotidique , Technique de Northern , Clonage moléculaire , ADN/génétique , Expression des gènes , Données de séquences moléculaires , Oligonucléotides/composition chimique , ARN messager/génétique , Trachée/immunologie , Trachée/microbiologie
19.
Arch Gen Psychiatry ; 48(4): 348-56, 1991 Apr.
Article de Anglais | MEDLINE | ID: mdl-1848971

RÉSUMÉ

Plasma levels of prolactin, growth hormone, corticotropin, and cortisol were measured at 15-minute intervals for 24 hours in nine unmedicated male schizophrenic patients and in nine age-matched normal male subjects. Each study was preceded by 3 days of habituation to the laboratory environment. Sleep was polygraphically recorded. The circadian and pulsatile variations present in each hormonal profile were quantitatively characterized with the use of computer algorithms specifically designed for analyses of hormonal fluctuations. The major abnormality of neuroendocrine release that was observed in the schizophrenic patients was an almost threefold enhancement of the sleep-related increase in the prolactin level, associated with an intensified frequency of nocturnal prolactin pulses. This increased stimulatory effect of sleep on prolactin secretion was evident immediately after sleep onset. The normal inhibition of cortisol secretion during early sleep was absent in schizophrenic patients. The major sleep abnormalities were a prolonged sleep latency and a reduction in total rapid eye movement stage sleep. During wakefulness, prolactin and cortisol levels were normal. The 24-hour profile of growth hormone was unaltered in schizophrenic patients, and a sleep-onset growth hormone pulse was observed in all patients. No abnormalities were noted in the levels or temporal organization of corticotropin secretion. Both the amplitude and the timing of the cortisol rhythm were normal. We conclude that, in schizophrenic men, pituitary-adrenal function and circadian time-keeping are normal but prolactin secretion is hyperresponsive to the physiologic stimulus of sleep onset. Schizophrenia thus appears to be characterized by a subset of neuroendocrine disturbances distinct from that observed in major endogenous depression.


Sujet(s)
Hormone corticotrope/sang , Rythme circadien/physiologie , Hormone de croissance/sang , Hydrocortisone/sang , Prolactine/sang , Schizophrénie/physiopathologie , Sommeil/physiologie , Adulte , Humains , Axe hypothalamohypophysaire/physiopathologie , Mâle , Axe hypophyso-surrénalien/physiopathologie , Schizophrénie/sang , Sommeil paradoxal/physiologie
20.
Int J Biometeorol ; 34(1): 1-14, 1990 May.
Article de Anglais | MEDLINE | ID: mdl-2361773

RÉSUMÉ

The affect of negative thermal stress on hematological variables at rest, and during submaximal (sub ex) and maximal exercise (max ex) were observed for young males who volunteered in two experimental sessions, performed in cold (0 degree C) and in normal room temperature (20 degrees C). At rest, hematological variables such as RBC and derivates Hb and Hct were significantly increased (P less than 0.05) during cold stress exposure, while plasma volume decreased. The findings of this study suggest that the major factor inducing hypovolemia during low thermal stress can be imputed to local plasma water-shift mechanisms and especially to a transient shift of plasma water from intra- to extravascular compartments. Rest values for WBC and platelets (Pla) were also slightly increased during cold stress exposure. However this increase can partly be related to hemoconcentration but also to the cold induced hyperventilation activating the lung circulation. Maximal exhaustive exercise induced, in both experimental temperatures, significant (P less than 0.05) increments of RBC, Hb, Hct, and WBC while plasma volume decreased. However, Pla increase was less marked. On the other hand, cold stress raised slightly the observed variations of the different hematological variables. Submaximal exercise induced a similar, though non-significant, pattern for the different hematological variables in both experimental conditions. Observed plasma volume (delta PV%) reduction appears during exercise. However cold stress induced resting plasma volume variations that are transferred at every exercise level. Neither exercise nor cold inducement significantly modified the hematological indices (MCH, MCV, MCHC). In conclusion hematological variables are affected by cold stress exposure, even when subjects perform a physical activity.


Sujet(s)
Phénomènes physiogiques du sang , Climat froid/effets indésirables , Acclimatation/physiologie , Adulte , Hémogramme , Volume sanguin/physiologie , Exercice physique/physiologie , Hémoglobines/métabolisme , Humains , Mâle , Stress physiologique/sang
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