Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 161
Filter
1.
Arch Pediatr ; 30(1): 1-9, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36509624

ABSTRACT

Cystic fibrosis is a severe monogenic disease that affects around 7400 patients in France. More than 2100 mutations in the cystic fibrosis conductance transmembrane regulator (CFTR), the gene encoding for an epithelial ion channel that normally transports chloride and bicarbonate, lead to mucus dehydration and impaired bronchial clearance. Systematic neonatal screening in France since 2002 has enabled early diagnosis of cystic fibrosis. Although highly demanding, supportive treatments including daily chest physiotherapy, inhaled aerosol therapy, frequent antibiotic courses, nutritional and pancreatic extracts have improved the prognosis. Median age at death is now beyond 30 years. Ivacaftor was the first CFTR modulator found to both reduce sweat chloride concentration and improve pulmonary function in the rare CFTR gating mutations. Combinations of modulators such as lumacaftor + ivacaftor or tezacaftor + ivacaftor were found to improve pulmonary function both in patients homozygous for the F508del mutation characterized by the lack of CFTR protein and those heterozygous for F508del with minimal CFTR activity. The triple combination of ivacaftor + tezacaftor + elexacaftor was recently shown to significantly improve pulmonary function and quality of life, to normalize sweat chloride concentration, and to reduce the need for antibiotic therapy in patients with at least one F508del mutation (83% in France). These impressive data, however, need to be confirmed in the long term. Nevertheless, it is encouraging to hear treated patients testify about their markedly improved quality of life and to observe that the number of lung transplants for cystic fibrosis decreased dramatically in France after 2020, despite the COVID pandemic, with no increase in deaths without lung transplant.


Subject(s)
Cystic Fibrosis , Adult , Humans , Infant, Newborn , Chlorides/metabolism , Cystic Fibrosis/drug therapy , Cystic Fibrosis/genetics , Cystic Fibrosis Transmembrane Conductance Regulator/genetics , Drug Combinations , Mutation , Quality of Life
2.
Bull Acad Natl Med ; 205(6): 579-586, 2021 Jun.
Article in French | MEDLINE | ID: mdl-33753947

ABSTRACT

SARS-CoV-2 pandemics is characterized by a high level of infectivity and a high mortality among adults at risk (older than 65 years, obesity, diabetes, systemic hypertension). Following a common viral pneumonia, a multisystem inflammatory syndrome sometimes occurs, including an Acute Respiratory Distress Syndrome (ARDS) carrying a high mortality. Unlike most common respiratory viruses, children seem less susceptible to SARS-CoV-2 infection and generally develop a mild disease with low mortality. However, clusters of severe shock associated with high levels of cardiac biomarkers and unusual vasoplegia requiring inotropes, vasopressors and volume loading have been recently described. Both clinical symptoms (i.e., high and persistent fever, gastrointestinal disorders, skin rash, conjunctivitis and dry cracked lips) and biological signs (e.g., elevated CRP/PCT, hyperferritinemia) resembled Kawasaki disease. In most instances, intravenous immunoglobin therapy improved the cardiac function and led to full recovery within a few days. However, adjunctive steroid therapy and sometimes biotherapy (e.g., anti-IL-1Ra, anti-IL-6 monoclonal antibodies) were often necessary. Although almost all children fully recovered within a week, some of them developed coronary artery dilation or aneurysm. Thus, a new 'Multisystem Inflammatory Syndrome associated with SARS-CoV-2' has been recently described in children and helps to better understand Kawasaki disease pathophysiology.

3.
Arch Pediatr ; 27(8): 474-479, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33028494

ABSTRACT

Intravenous fluids are frequently used in hospitalized children. Hypotonic fluids have been the standard of care in pediatrics for many years. This might be explained by the empiricism of early recommendations favoring fluids with dextrose, but an insufficient amount of sodium. The risk of hyponatremia (<135mmol/L) might be increased by the occurrence of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in the course of common acute diseases (e.g., bronchiolitis, acute gastroenteritis, encephalitis, meningitis) in children. Severe hyponatremia (<130mmol/L) is often associated with neurologic complications leading to sequelae or even death. Over the last few years, hyponatremia induced by hypotonic fluids has been increasingly reported, and significant progress has been made in the understanding of cerebral edema and osmotic demyelination. Several randomized clinical trials have shown weak but significant evidence that isotonic fluids were superior to hypotonic solutions in preventing hyponatremia. However, clinical practices have not changed much in France, as suggested by the analysis of intravenous fluids ordered from the Assistance Publique-Hôpitaux de Paris (AP-HP) central pharmacy (PCH) in 2017. Therefore, it would be advisable that national guidelines be released under the French Health Authorities regarding the safe infusion of infants and children.


Subject(s)
Fluid Therapy/adverse effects , Hyponatremia/etiology , Hypotonic Solutions/adverse effects , Child , Child, Preschool , Fluid Therapy/methods , France , Hospitalization , Humans , Hyponatremia/mortality , Hyponatremia/physiopathology , Hyponatremia/prevention & control , Infant , Isotonic Solutions , Practice Guidelines as Topic , Practice Patterns, Physicians' , Risk Factors , Severity of Illness Index
5.
Arch Dis Child ; 101(4): 359-64, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26729746

ABSTRACT

OBJECTIVE: To study reconstitution and preparation dosing errors of liquid oral medications given by caregivers to children. METHODS: A prospective observational study was carried out in the departments of general paediatrics and emergency paediatrics at the Robert-Debré Children's University Hospital. An interview with caregivers involved (1) practical reconstitution and preparation of an oral liquid medication from a prescription drawn at random (amoxicillin (Clamoxyl, dosing spoon) or josamycin (Josacine, dose-weight pipette)) and (2) a questionnaire about their use. RESULTS: One hundred caregivers were included. Clamoxyl and Josacine were incorrectly reconstituted in 46% (23/50) and 56% (28/50) of cases, respectively, with a risk of underdosing of Clamoxyl (16/23) and overdosing of Josacine (23/28). Dose preparation with the dosing spoon was incorrect in 56% of cases, and in 10% of cases with the dose-weight pipette. Female sex, native French speaker, and age were significantly associated with correct reconstitution. Male sex and medication were significantly associated with correct preparation. CONCLUSIONS: This study highlights the high incidence of errors made by caregivers in reconstituting and preparing doses of these liquid oral medicines, which are associated with considerable risks of over- and underdosing. Factors associated with these errors have been identified which could help health professionals to optimise their strategy for educating families about the use of liquid oral medications and the need to check that they understand these instructions.


Subject(s)
Amoxicillin/administration & dosage , Anti-Bacterial Agents/administration & dosage , Josamycin/administration & dosage , Medication Errors/statistics & numerical data , Administration, Oral , Adolescent , Adult , Caregivers , Child , Child, Preschool , Female , Hospitals, Pediatric , Humans , Incidence , Male , Pediatrics , Prospective Studies , Surveys and Questionnaires
6.
Orthop Traumatol Surg Res ; 101(5): 597-600, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26198018

ABSTRACT

INTRODUCTION: Diaphyseal forearm fractures are very common pediatric traumas. At present, distal radius metaphyseal fractures are often successfully treated with closed reduction by emergency physicians. However, the management of diaphyseal fractures remains controversial. The purpose of this study was to analyze the results of diaphyseal forearm fractures in the emergency department (ED) in children. MATERIALS AND METHODS: In a prospective 2-year-study, all closed diaphyseal forearm fractures in patients under 15, with an angle of >15° and treated by closed reduction in the ED were included. Fractures with overlapping fragments were excluded. Reduction was performed by an emergency physician, with a standardized analgesic protocol (painkillers and nitrous oxide). Clinical tolerance was checked within the first 24hours, and the radiographic stability of reduction was assessed at days 8 and 15. Initial and final follow-up radiographs were analyzed. Elbow and wrist range of motion was assessed at the final follow-up. RESULTS: Sixty patients (41 boys and 19 girls) were included. Mean age was 5.2 years old (±3). At initial evaluation, the maximum angle was 30° (±11.3). After reduction, the maximum angle was significantly reduced (30° vs. 5°, P<0.001). Mean immobilization in a cast was 11.7 weeks (±2). There were no cast related complications in any of these children. There was no surgery for secondary displacement. Full range of motion was obtained in all patients at the final follow-up. DISCUSSION: The outcome of conservative treatment of closed diaphyseal forearm fractures, without overlapping fragments was excellent. However, reduction is usually performed in the operating room by orthopedic surgeons under general anesthesia and requires hospitalization, which is very expensive. The results of this study show that high quality care may be obtained in the ED by a trained and experienced team. These results are similar to those for distal metaphyseal fractures, which could extend the indications for reduction in the ED. LEVEL OF EVIDENCE: Level IV. Retrospective study.


Subject(s)
Emergency Service, Hospital , Fractures, Closed/therapy , Manipulation, Orthopedic , Radius Fractures/therapy , Ulna Fractures/therapy , Adolescent , Casts, Surgical , Child , Child, Preschool , Diaphyses/injuries , Feasibility Studies , Female , Humans , Infant , Male , Prospective Studies
7.
Arch Pediatr ; 22(3): 255-9, 2015 Mar.
Article in French | MEDLINE | ID: mdl-25656458

ABSTRACT

Suicide attempts (SA) in children are often considered rare and poorly studied. The aim of this study was to explore the clinical characteristics of SA in children under 12 years of age. A retrospective assessment was conducted in 30 consecutive SAs reported in children under 12 years of age admitted to the emergency department at the Robert-Debré University Hospital (Paris, France) from 2007 to 2010 and the Regional University Hospital (Besançon, France) from 2000 to 2008. All suicide attempters were directly assessed at the somatic and psychiatric level. Patients were 8-11 years old (mean, 10.2±0.8). The sex ratio was 0.9 boys for 1 girl. The leading SA methods were poisoning by medication (53.3%), hanging or strangulation (23.3%), jumping from a height (16.7%), poisoning by chemicals (3.3%), and lesions inflicted by sharp objects (3.3%). In addition, SAs were characterized by high lethality (43.7%) contrasting with their low to moderate suicidal intentionality (43.8% and 56.2%, respectively). In conclusion, we reported that SA in children differs from those of adolescents by their greater lethality related to the methods used, but contrasting with the low intentionality mentioned by these patients.


Subject(s)
Suicide, Attempted/statistics & numerical data , Age Distribution , Child , Female , France , Humans , Male , Retrospective Studies , Sex Distribution
8.
Nitric Oxide ; 38: 8-16, 2014 Apr 30.
Article in English | MEDLINE | ID: mdl-24566008

ABSTRACT

RATIONAL: Inhaled nitric oxide (NO) is frequently administered to full term and preterm newborns in various clinical settings in order to alleviate pulmonary hypertension whilst improving oxygenation. However, the physiological effect of NO on early postnatal lung development has not yet been clearly described. We therefore investigated whether NO administered by inhalation affects lung development at early postnatal life. METHODS: Pregnant rats were placed in a chamber containing 5 ppm (iNO-5 ppm group) and 20 ppm NO (iNO-20 ppm group), started from the last day of their pregnancy in order to keep rat pups under ambient NO from birth to 7 days postnatal. Control animals were kept at room air and all rat pups were sacrificed at postnatal day 7 and day 14. RESULTS: Lung-to-body weight and wet-to-dry lung weight ratios did not significantly differ among 3 groups at postnatal day 7 and day 14. Vascular volume densities (Vv) in both NO groups (5 and 20 ppm) were higher than controls (P<0.05; P<0.001). Pulmonary vessel number was significantly increased in iNO-20 ppm group. Radial alveolar counts (RAC) and mean linear intercepts (MLI) markedly increased (consistent with increased alveolarization) in iNO-20 ppm group. This was associated with upregulation of VEGF/VEGFR-2, MT1-MMP/MMP2 and HO-1 protein expression in iNO-20 ppm group. CONCLUSIONS: We concluded that inhaled NO at 20 ppm enhanced lung development possibly through increased expression of HO-1, VEGF/VEGFR-2, and MMP2 at early stage of postnatal rat life.


Subject(s)
Lung/drug effects , Lung/growth & development , Nitric Oxide/administration & dosage , Nitric Oxide/pharmacology , Administration, Inhalation , Animals , Body Weight/drug effects , Female , Lung/metabolism , Organ Size/drug effects , Pregnancy , Rats , Rats, Sprague-Dawley
9.
Eur J Clin Microbiol Infect Dis ; 31(7): 1295-303, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22002230

ABSTRACT

Acute respiratory tract infections (ARTIs) are the main reason for antibiotic prescription in children. In 2005, the French Drug Agency published guidelines to minimise inappropriate use of antibiotics for ARTI. The purpose of this study was to assess the impact of implementing these guidelines in a paediatric emergency department. We retrospectively analysed data collected prospectively in a French paediatric emergency department from November 2005 (date of guideline implementation) to October 2009. For each child diagnosed with ARTI, we collected age, diagnosis, and prescribed antibiotics. We computed antibiotic prescription rates in the study population. During the study period, 53,055 children were diagnosed with ARTI and 59% of the 22,198 antibiotic prescriptions given at discharge were related to ARTI. The proportion of ARTI patients given antibiotic prescriptions fell from 32.1% during the first year to 21% in year 4 (p<10(-4), Cochran-Armitage test). Amoxicillin-clavulanic acid and amoxicillin accounted for 50% and 34% of antibiotic prescriptions for ARTI, respectively. French antibiotic guidelines led to significant decreases in antibiotic prescription for ARTI in our paediatric emergency department.


Subject(s)
Anti-Bacterial Agents/administration & dosage , Bacterial Infections/drug therapy , Drug Therapy/standards , Health Services Research , Respiratory Tract Infections/drug therapy , Adolescent , Child , Child, Preschool , Drug Prescriptions/statistics & numerical data , Emergency Medical Services , Female , France , Hospitals, Pediatric , Humans , Infant , Infant, Newborn , Male , Practice Guidelines as Topic , Prospective Studies
10.
Arch Pediatr ; 18(12): 1271-7, 2011 Dec.
Article in French | MEDLINE | ID: mdl-21963378

ABSTRACT

OBJECTIVES: Evaluating the frequency and modalities of transmissible infection prevention counseling in children before a stay in tropical or subtropical areas. METHODS: Description of the frequency and modalities of transmissible infection prevention counseling (except specific vaccination) given prior to travel in children attending a tertiary care center in Paris, France, for fever occurring within 3 months following a return from Africa. Data were collected retrospectively from medical observations and telephone interviews with parents. RESULTS: A total of 173 children were included; 98 and 75 returned from sub-Saharan Africa and North Africa, respectively. Forty-one percent were less than 2 years old. Eighty-one percent of the children had consulted before leaving. Among children who returned from North Africa, the proportion of children who had a specific preventive consultation before travel was lower than among children who returned from sub-Saharan Africa (respectively, 72.1% versus 94.7%; p<0.001). In children having consulted before traveling, specific hygiene and diet advice had been given in 72% of cases but less frequently in children who traveled in North Africa compared to children who traveled to sub-Saharan Africa (respectively, 57.8% vs. 92.2%; p<0.001). Among children who returned from North Africa, those who had no preventive consultation before travel had febrile gastrointestinal infection more frequently than those who had a consultation before traveling (p=0.003). CONCLUSION: Although in this study the majority of children traveling to Africa receive transmissible infection prevention counseling before the travel, prevention could be improved, particularly before a stay in North Africa.


Subject(s)
Directive Counseling , Fever , Gastrointestinal Diseases , Infection Control , Primary Prevention , Travel , Africa South of the Sahara , Africa, Northern , Algorithms , Child, Preschool , Directive Counseling/statistics & numerical data , France/epidemiology , Gastrointestinal Diseases/epidemiology , Gastrointestinal Diseases/prevention & control , Humans , Infant , Population Surveillance , Primary Prevention/methods , Surveys and Questionnaires , Vaccination
11.
Emerg Med J ; 28(11): 924-6, 2011 Nov.
Article in English | MEDLINE | ID: mdl-20943835

ABSTRACT

INTRODUCTION: The influenza A (H1N1) 2009 outbreak caused death and a disruption of public health services. Rapid influenza diagnostic tests (RIDT) could be helpful to ease the triage of patients and prevent an overload of emergency and laboratory facilities. OBJECTIVES: To compare the sensitivity and specificity of the Clearview Exact Influenza A&B test and real-time reverse transcription(RT)-PCR to detect influenza A (H1N1) 2009 in a paediatric emergency department of a paediatric teaching hospital in Paris, France. METHODS: 76 children with an influenza-like illness and either severe symptoms or an underlying medical condition were prospectively recruited between July 2009 and October 2009. RIDT and RT-PCR were simultaneously performed and compared. RESULTS: Among 39 influenza A (H1N1) 2009 RT-PCR-positive children (median age 5 years), 23 Clearview Exact Influenza A&B tests were positive. Sensitivity was 59% (95% CI 42.2 to 74) and specificity was 94.6% (95% CI 80.5 to 99.1). CONCLUSIONS: This study shows a sensitivity of RIDT of 59%, in agreement with other prospective studies, which could be useful in clinical practice for diagnosis influenza A (H1N1) 2009 in children. In outbreaks of a high prevalence, such as the 2009 outbreak, this test can help to prevent an overload of public health services.


Subject(s)
Disease Outbreaks , Influenza A Virus, H1N1 Subtype , Influenza, Human/diagnosis , Adolescent , Child , Child, Preschool , Diagnostic Tests, Routine/standards , Female , Humans , Infant , Influenza, Human/epidemiology , Male , Paris/epidemiology , Polymerase Chain Reaction/methods , Prospective Studies , Sensitivity and Specificity
13.
Eur J Clin Microbiol Infect Dis ; 29(3): 341-6, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20063027

ABSTRACT

Invasive group A streptococcal (GAS) infections have a broad and evolving clinical spectrum, associated with various GAS genotypes and/or virulence factors that are only poorly described in children. We aimed to assess the clinical and molecular characteristics of invasive GAS infections in 28 children admitted from 2000 to 2007 at a large French pediatric tertiary care center. The GAS isolates were characterized molecularly by emm-typing and by the determination of the main virulence factors: speA, speB, speC, smeZ-1, ssa, sic, and silC. The median age of the children was 2.9 years. Osteoarticular infection (OAI) was the main clinical manifestation (n=15/28, 53%). emm-1 predominated (n=10/28), followed by emm-12, 3, and 4. No significant correlation was found between emm type and clinical manifestations, but emm-1 predominated in cases of OAI (n=7/15) and was associated with speA, speB, smeZ-1, and sic virulence factor genes. In this pediatric study, we describe a predominance of OAI associated with emm-1 GAS. Further larger international pediatric studies, including host immunity evaluation, are needed in order to better assess the pathogenesis of GAS infection in children.


Subject(s)
Streptococcal Infections/microbiology , Streptococcus pyogenes/genetics , Antigens, Bacterial/genetics , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/genetics , Bone Diseases, Infectious/epidemiology , Bone Diseases, Infectious/microbiology , Carrier Proteins/genetics , Child, Preschool , Cohort Studies , Exotoxins/genetics , Female , France/epidemiology , Humans , Male , Streptococcal Infections/epidemiology , Virulence Factors/genetics
14.
Arch Pediatr ; 16 Suppl 1: S1-8, 2009 Sep.
Article in French | MEDLINE | ID: mdl-19836663

ABSTRACT

With the advent of prenatal steroids, postnatal exogenous surfactant and less aggressive respiratory support, premature infants can develop chronic lung disease without even acute respiratory distress. This "new bronchopulmonary dysplasia" could be the result of impaired postnatal growth. Several experimental studies have suggested a possible role of the vascular endothelial growth factor/nitric oxide (VEGF/NO) pathway in restoring pulmonary angiogenesis and enhancing distal lung growth. The results of the clinical studies are, however, inconclusive, and it is currently unclear which subsets of premature infants might benefit from inhaled nitric oxide. Besides, severe intracranial haemorrhage and/or cystic periventricular leukomalacia may affect the most immature babies, many of whom are spared from severe initial respiratory disease. Recently, inhaled nitric oxide was shown to significantly decrease the incidence of these neurological events, and to improve the long-term outcome in a few clinical trials. At times neuroprotective, at times neurotoxic, nitric oxide is capable of divergent effects depending upon the extent of cerebral damage, the redox state of the cell, and the experimental model used. Recently, inhaled nitric oxide had recognized to have dramatic remote effects including angiogenesis and maturation on the developing brain in rodent pups. Therefore, the developmental consequences of inhaled NO should be further investigated to ensure its safety on the developing brain and to test its potential neurprotective effect.


Subject(s)
Brain/drug effects , Lung/drug effects , Nitric Oxide/adverse effects , Nitric Oxide/therapeutic use , Administration, Inhalation , Brain/growth & development , Bronchodilator Agents/therapeutic use , Humans , Infant, Newborn , Infant, Premature , Infant, Premature, Diseases/drug therapy , Lung/growth & development , Lung Diseases/drug therapy , Neuroprotective Agents/adverse effects , Neuroprotective Agents/therapeutic use , Respiratory Insufficiency/drug therapy , Safety
15.
Med Mal Infect ; 39(7-8): 452-61, 2009.
Article in French | MEDLINE | ID: mdl-19409742

ABSTRACT

Bacterial meningitis is a medical emergency requiring prompt recognition and evaluation and urgent initiation of appropriate antibacterial therapy. However, early recognition of severe bacterial infection including bacterial meningitis is a challenge in infants. Two clinical forms are basically observed in infants and young children: firstly, clinical meningitis which is characterized by fever, usually greater than 39 degrees C, and poorly specific gastrointestinal signs such as refusal of feeding and/or vomiting; irritability, abnormal crying, bulging fontanel, unusual generalized seizures occurring before six months of age and lasting more than 10 min should draw the clinician's attention and lead him/her to perform a lumbar puncture and initiate antibiotics; secondly, severe sepsis which is characterized by tachycardia, cold and/or mottled limbs and sometimes leg pain which should suggest a meningococcal disease; it is quite urgent to administer rapid fluid loading and antibiotic treatment while postponing lumbar puncture before the septic cascade evolves towards septic shock, extensive hemorrhagic rash, and ischemic limbs. Given the relative frequency of viral self-limiting diseases and rarity of serious bacterial infections, guidelines were published to guide the clinician's decision when dealing with a febrile infant. However, an alternative to these guidelines was recently suggested with a more clinically oriented decision-making attitude appearing as efficient while limiting hospitalizations.


Subject(s)
Meningitis, Bacterial/diagnosis , Anorexia/etiology , Child, Preschool , Cranial Fontanelles/pathology , Diagnosis, Differential , Fever/etiology , Hospitalization , Humans , Infant , Muscle Hypotonia/etiology , Pain/etiology , Predictive Value of Tests , Seizures/etiology , Spinal Puncture
16.
Exp Lung Res ; 34(7): 355-71, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18716924

ABSTRACT

Endogenous nitric oxide (NO) mediates pulmonary vasodilatation at birth, but inhaled NO fails to reduce pulmonary vascular resistance (PVR) in newborns with congenital diaphragmatic hernia (CDH). This study was designed to investigate the effects of ventilation, and the nature of its endogenous mediator, in fetal lambs with experimental CDH. Investigations at 138 days of gestation showed that ventilation markedly decreased PVR. Inhibition of NO synthesis reduced ventilation-induced pulmonary vasodilatation in vivo and increased in vitro isometric tension of vascular rings. Ventilation therefore reduces PVR at birth in lambs with CDH, and endogenous NO seems to contribute to this reduction.


Subject(s)
Hernia, Diaphragmatic/therapy , Lung/blood supply , Nitric Oxide/metabolism , Pulmonary Circulation , Respiration, Artificial , Vasodilation , Animals , Disease Models, Animal , Electric Stimulation , Enzyme Inhibitors/pharmacology , Gestational Age , Hemodynamics , Hernia, Diaphragmatic/physiopathology , Hernias, Diaphragmatic, Congenital , Nitric Oxide Synthase/antagonists & inhibitors , Nitric Oxide Synthase/metabolism , Nitroarginine/pharmacology , Pulmonary Circulation/drug effects , Sheep , Vascular Resistance , Vasodilation/drug effects
19.
Eur Respir J ; 19(3): 525-9, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11936533

ABSTRACT

In the vascular system, synthesis of the potent vasodilator nitric oxide (NO) is tightly regulated by the constitutively expressed endothelial NO synthase (eNOS). Activity of eNOS is controlled by Ca2+/calmodulin and various seryl/threonyl protein kinases. Less is known about the importance of phosphorylation and dephosphorylation of tyrosyl residues. Therefore the role of tyrosine phosphatase on the modulation of isolated rat pulmonary artery tone has been assessed. Inhibition of tyrosine phosphatase by sodium orthovanadate (SOV, 1x10(-6) M) significantly: 1) increased phenylephrine-induced vasoconstriction and 2) decreased endothelium-dependent relaxation to acetylcholine, but had no effect on endothelium-independent relaxation to the NO donor, sodium nitroprusside. In phenylephrine-precontracted pulmonary arterial rings, SOV (1x10(-7)-1x10(-5) M) had no effect on vascular tone but significantly relaxed rings which were pretreated with the NO-synthase inhibitor, N(omega)-nitro-L-arginine-methyl ester (L-NAME). SOV-induced relaxation in the presence of L-NAME was, however, abolished by glibenclamide. In conclusion, inhibition of tyrosine phosphatase altered pulmonary vascular tone by increasing vasoconstrictor response to phenylephrine and decreasing endothelium-dependent relaxation to acetylcholine. Furthermore, the tyrosine phosphatase inhibitor, sodium orthovanadate, exhibited original vasodilator properties which were only observed when nitric oxide synthesis was inhibited. Thus a new pathway involving the inhibitory effect of nitric oxide on a glibenclamide-sensitive diffusible relaxing factor, that might play an important role in the control of pulmonary vascular tone is described.


Subject(s)
Muscle, Smooth, Vascular/drug effects , Protein Tyrosine Phosphatases/metabolism , Pulmonary Artery/drug effects , Vanadates/pharmacology , Acetylcholine/pharmacology , Animals , Culture Techniques , Drug Interactions , Endothelium, Vascular/drug effects , Endothelium, Vascular/physiology , Male , Models, Animal , Muscle, Smooth, Vascular/physiology , NG-Nitroarginine Methyl Ester/pharmacology , Phenylephrine/pharmacology , Probability , Protein Tyrosine Phosphatases/drug effects , Rats , Rats, Sprague-Dawley , Sensitivity and Specificity , Statistics, Nonparametric , Vasoconstriction/drug effects , Vasodilation/drug effects
20.
Arch Pediatr ; 8(8): 843-52, 2001 Aug.
Article in French | MEDLINE | ID: mdl-11524916

ABSTRACT

Despite significant progress in intensive care medicine, the mortality of septic shock has not changed in recent years. Early recognition of subtle signs in favor of meningococcal sepsis, early antibiotic treatment, and aggressive hemodynamic support remains the cornerstone of therapy of severe meningococcal shock in children. Recent work has emphasized the role of genetic polymorphisms in various systems to explain the most severe cases: anti-inflammatory cytokine profile IL-10/TNF-alpha, elevated levels of plasminogen activator inhibitor type-1, variants of the gene for mannose-binding lectin complement pathway. This may explain the disillusionment of pediatric intensivists, and the general failure of immunotherapy for sepsis. Reasonable hope lies upon new meningococcal vaccines.


Subject(s)
IgA Vasculitis/physiopathology , Meningococcal Infections/complications , Polymorphism, Genetic , Shock, Septic/physiopathology , Child , Coagulation Protein Disorders/complications , Cytokines/genetics , Cytokines/pharmacology , Genetic Predisposition to Disease , Humans , IgA Vasculitis/genetics , Shock, Septic/genetics
SELECTION OF CITATIONS
SEARCH DETAIL