[Epidemiology of nasopharyngeal colonization by Streptococcus pneumoniae and Haemophilus influenzae in a closed community of young children].
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Child↗
Biomedical subjects
J Raymond
Publications and source records attributed to J Raymond.
Effect of high hydrostatic pressures on 20S proteasome activity.
The 20S proteasome is the catalytic core of the ubiquitin proteolytic pathway, which is implicated in many cellular processes. The cylindrical structure of this complex consists of four stacked rings of seven subunits each. The central cavity is formed by two beta catalytic subunit rings in which protein substrates are progressively degraded. The 20S proteasome is isolated in a latent form which can be activated in vitro by various chemical and physical treatments. In this study, the effects of high hydrostatic pressures on 20S proteasome enzymatic activity were investigated. When proteasomes were subjected to increasing hydrostatic pressures, a progressive loss of peptidase activities was observed between 75 and 150 MPa. The inactivation also occurred when proteasomes were pressurized in the presence of synthetic peptide substrates; this may be the result of the dissociation of the 20S particle into its subunits under pressure, as was shown by PAGE. Pressurized proteasomes also lost their caseinolytic activity. In contrast, in the presence of casein, the pressure-induced inactivation and the dissociation of the 20S particles were prevented. In addition, in comparison to that observed at atmospheric pressure, their caseinolytic activity was increased under pressure. Following depressurization, the caseinolytic activity returned to basal levels but was further enhanced following an additional pressurization treatment. Thus, the structure of the 20S particle exhibits a certain degree of plasticity. This pressure-induced activation of the 20S proteasome is discussed in relation to its hollow structure, its currently accepted proteolytic mechanism and the general effect of high pressures on the biochemical reactions and structures of biopolymers.
Animals↗
Interferon-alpha in viral and bacterial gastroenteritis: a comparison with C-reactive protein and interleukin-6.
The aim of the study was to identify serum markers able to differentiate bacterial and viral origin in acute diarrhoea. Interferon-alpha (INF-alpha), C-reactive protein (CRP) and interleukin-6 were determined on admission in the sera of 119 children aged between 1 mo and 14 y who were hospitalized for rotavirus (n = 60) or bacterial diarrhoea (Salmonella spp. 39 cases, Shigella spp. 15 cases, Campylobacter jejuni 5 cases). CRP concentration was >10 mg/l in 48.3% of children with viral gastroenteritis and 86.4% of children with bacterial gastroenteritis. IL6 concentration was >100 pg/ml in 11.7% and 26.3% of cases, respectively. INF-alpha was detected in 79.1% of children with rotavirus (sens 79%) and in 3.5% (spec 93%) with bacterial gastroenteritis. However the INF-alpha assay takes 48 h and pathogens are often identified from stools before interferon results are available. We found that serum markers are not discriminating enough to differentiate between viral and bacterial gastroenteritis in emergency cases.
Acute Disease↗
Degradation of an ubiquitin-conjugated protein is associated with myoblast differentiation in primary cell culture.
At the early stages of myogenesis, myoblasts fuse to form multinucleated myotubes. This morphological differentiation is the result of dynamic changes in gene regulation and expression. The ubiquitin proteasome-dependent pathway has been reported to play an important role in many aspects of cellular functions such as regulation of growth and cell cycle progression. In this study, we showed that the amount of mRNA's corresponding to the iota subunit of the 20S proteasome, the level of the S4 subunit of the 19S complex and the 20S and 26S proteasomes peptidase activities increased during myoblast fusion. Cell permeable 20S proteasome inhibitor prevented fusion with concomitant accumulation of ubiquitin-conjugated protein. On the other hand, inhibition of ubiquitin ligase E3 enzymes prevented the formation of ubiquitin conjugate and decreased the fusion process. These results strongly support the involvement of the ubiquitin-proteasome proteolytic pathway in the events leading to myoblast fusion.
Animals↗
20S proteasome, hsp90, p97 fusion protein, PA28 activator copurifying oligomers and ATPase activities.
Whether hsp90 acts in an ATP-dependent or independent way is of crucial importance for understanding the molecular mechanism of this chaperone and, to day, the involvement of ATP hydrolysis in hsp90 function is still a controversial subject. ATPase activities may be detected in partially purified hsp90's preparations from rabbit muscle. We demonstrate that the major contaminant associated with hsp90 is the p97 fusion protein and that these oligomeric structures are copurifying together with the 20S proteasome and its PA28 activator. Improving the purification procedure permits to separate hsp90 and p97 to homogeneity. Then, our attempts failed to detect any significant ATPase activity in the hsp90 fraction. Thus, p97 would be principally responsible for the ATPase activity detected in partially purified hsp90 preparations from rabbit muscle.
Adenosine Triphosphatases↗
In-vitro bactericidal activity of cefpirome and cefamandole in combination with glycopeptides against methicillin-resistant Staphylococcus aureus.
The bactericidal activity in vitro of cefpirome plus either vancomycin or teicoplanin was compared with that of a cefamandole-vancomycin combination against ten clinical isolates of homogeneous methicillin-resistant Staphylococcus aureus. Cefpirome (0.125 x MIC) combined with vancomycin (0.5-2 x MIC) or teicoplanin (0.5-4 x MIC) acted synergically against the ten isolates. Similar effects were observed with the cefamandole-vancomycin combination, except that for one isolate, higher cefamandole concentrations (0.25-1 x MIC) were required.
Anti-Bacterial Agents↗
The rate of Helicobacter pylori infection in children with growth retardation.
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Adolescent↗
Managing intrafamilial dissemination of Helicobacter pylori gastric infection improves eradication rate in children.
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Adolescent↗
Cardiorespiratory responses to arm cranking and electrical stimulation leg cycling in people with paraplegia.
PURPOSE: The purpose of this study was to assess the cardiorespiratory responses during arm exercise with and without concurrent electrical stimulation-induced leg cycling in people with paraplegia. METHODS: On separate days, 10 subjects with spinal cord injuries (T5-T12) performed either arm cranking (ACE), or simultaneous arm cranking + electrical stimulation-induced leg cycling (ACE+ES-LCE) graded exercise tests. RESULTS: During submaximal, steady-state exercise, ACE+ES-LCE elicited significantly higher VO2, (by 0.25-0.28 L x min(-1)) stroke volume (by 13 mL), and VE(BTPS) (by 9.4 L x min(-1)) compared with ACE alone. In contrast, there were no significant differences of submaximal HR, cardiac output, or power output between the exercise modes. At maximal exercise, ACE+ES-LCE elicited significantly higher VO2 (by 0.23 L x min(-1)) compared with ACE alone, but there were no differences in power output, HR, or VE(BTPS). CONCLUSIONS: These results demonstrate that during submaximal or maximal exercise there was a greater metabolic stress elicited during ACE+ES-LCE compared with during ACE alone. The higher stroke volume observed during submaximal ACE+ES-LCE, in the absence of any difference in HR, implied a reduced venous pooling and higher cardiac volume loading during ACE+ES-LCE. These results suggest that training incorporating ACE+ES-LCE may be more effective in improving aerobic fitness in people with paraplegia than ACE alone.
Adult↗
Endovascular treatment of hemifacial spasm associated with a cerebral arteriovenous malformation using transvenous embolization: case report.
OBJECTIVE AND IMPORTANCE: To illustrate that decompression of the facial nerve by transvenous endovascular treatment may relieve hemifacial spasm (HFS) caused by dilated veins. CLINICAL PRESENTATION: A 35-year-old man suffered severe chronic right HFS associated with a dilated right lateral mesencephalic vein lying in the vicinity of the facial nerve. This nonessential vein was recruited as a secondary collateral drainage from an inoperable left temporo-occipital arteriovenous malformation. INTERVENTION: The lateral mesencephalic vein was reached through the superior petrosal sinus using a transfemoral venous approach and was occluded with interlocking detachable coils (Target Therapeutics, Freemont, CA). There was complete remission of HFS without recurrence after 2.5 years of follow-up. CONCLUSION: This case report supports vascular compression in the pathogenesis of HFS and suggests that facial nerve injury is not essential for the therapeutic effect of surgical decompression.
Adult↗
Comparison of procalcitonin with C-reactive protein, interleukin 6 and interferon-alpha for differentiation of bacterial vs. viral infections.
BACKGROUND: Procalcitonin (PCT) concentration increases in bacterial infections but remains low in viral infections and inflammatory diseases. The change is rapid and the molecule is stable, making it a potentially useful marker for distinguishing between bacterial and viral infections. METHODS: PCT concentration was determined with an immunoluminometric assay on plasma collected at admission in 360 infants and children hospitalized for bacterial or viral infection. It was compared with C-reactive protein (CRP), interleukin 6 and interferon-alpha measured on the same sample. RESULTS: The mean PCT concentration was 46 microg/l (median, 17.8) in 46 children with septicemia or bacterial meningitis. PCT concentration was > 1 microg/l in 44 of 46 in this group and in 59 of 78 children with a localized bacterial infection who had a negative blood culture (sensitivity, 83%). PCT concentration was > 1 microg/l in 16 of 236 children with a viral infection (specificity, 93%). PCT concentration was low in 9 of 10 patients with inflammatory disease and fever. A CRP value > or =20 mg/l was observed in 61 of 236 patients (26%) with viral infection and in 105 of 124 patients (86%) with bacterial infection. IL-6 was > 100 pg/ml in 14% of patients infected with virus and in 53% with bacteria. A secretion of interferon-alpha was found in serum in 77% of viral infected patients and in 8.6% of bacterial infected patients. CONCLUSIONS: In this study a PCT value of 1 microg/l or greater had better specificity, sensitivity and predictive value than CRP, interleukin 6 and interferon-alpha in children for distinguishing between viral and bacterial infections. PCT values are higher in invasive bacterial infections, but the cutoff value of 1 microg/l indicates the severity of the disease in localized bacterial infection and helps to decide antibiotic treatment in emergency room. PCT may be useful in an emergency room for differentiation of bacterial vs. viral infections in children and for making decisions about antibiotic treatments.
Adolescent↗
Value of prenatal diagnosis and early postnatal diagnosis of congenital toxoplasmosis: retrospective study of 110 cases.
We reviewed the files of 110 women with Toxoplasma seroconversion during pregnancy. Prenatal diagnosis was attempted for 94 women by amniotic fluid sampling. Toxoplasma gondii was detected by PCR, with or without tissue culture and mouse inoculation. The early neonatal diagnostic procedure included placental testing by PCR and/or mouse inoculation, cord blood serological testing, and comparison of maternal and newborn antibodies by Western blotting (WB). Serological follow-up of the infants was conducted during the first year of life or until the diagnosis of congenital toxoplasmosis (CT) could be ruled out. Congenital infection was diagnosed in 27 individuals (20 live births) in the prenatal and/or neonatal period. The sensitivity and specificity of prenatal diagnosis were 81 and 100%, respectively. Placental examination was positive for 66.7% of individuals with CT and was always negative for neonates without CT. Cord blood serology detected immunoglobulin M (IgM) and/or IgA in 80% of infected newborns, with respective specificities of 91.2 and 87.7%. By WB we detected bands on IgG and IgM blots recognized by the newborn serum but not by the maternal serum (neosynthesized IgG and/or IgM) for 88.2% of infected infants within the first 2 months of life with a specificity of 100%. Early postnatal diagnosis was negative for 2 of the 20 neonates with CT. Both of these newborns had a negative prenatal diagnosis and were asymptomatic, suggesting a very low parasite load. In conclusion, despite the use of advanced methods, some cases of congenital toxoplasmosis cannot be detected early, which underlines the importance of careful follow-up of newborns who are at risk.
Animals↗
Fibrinogen and vascular smooth muscle cell grafts promote healing of experimental aneurysms treated by embolization.
BACKGROUND AND PURPOSE: Residual necks and recurrences frequently occur after endovascular treatment of cerebral aneurysms. Addition of fibrinogen and vascular smooth muscle cells (VSMCs) to the embolic material may promote healing of embolized aneurysms by increasing neointima formation at the neck. METHODS: Bilateral carotid aneurysms were constructed with venous pouches in 31 dogs. Aneurysms were packed intraoperatively with bare Gelfoam sponges, sponges treated with fibrinogen, or fibrinogen sponges seeded with the animal's own VSMCs or peripheral blood mononuclear cells. Animals were killed after angiography at 3 weeks, and morphometric studies were performed to measure the thickness of the neointima at the neck of treated lesions. Angiographic results and mean thickness of neointimas were compared using ANOVA. In 8 animals, 1 aneurysm was embolized with sponge seeded with VSMCs transduced by adenoviral infection to express a fluorescent protein (green fluorescent protein), and gene expression was monitored for 4, 7, 14, and 21 days by fluorescent microscopy. RESULTS: Aneurysms treated with sponges seeded with VSMCs had significantly thicker neointimas and were more completely obliterated at 3 weeks than control aneurysms treated with fibrinogen sponges. Peripheral blood mononuclear cells could not reproduce these findings. Sponges treated with fibrinogen alone promoted formation of a thicker neointima than bare sponges. Transduced cells transplanted into in vivo aneurysms still expressed green fluorescent protein at 3 weeks. CONCLUSIONS: VMSC grafts can improve healing of experimental aneurysms treated by embolization. Transplantation of cells transduced to express a foreign gene opens the way for in situ gene therapy for cerebral aneurysms.
Adenoviridae↗
Transarterial embolization of aneurysms associated with spinal cord arteriovenous malformations. Report of four cases.
The authors sought to show the feasibility and discuss the rationale of embolization of aneurysms associated with spinal cord arteriovenous malformations (SCAVMs). The authors reviewed the clinical presentation, magnetic resonance (MR) images, spinal angiograms, and clinical evolution of four patients treated for aneurysms associated with an SCAVM. Aneurysms were located on branches of the anterior spinal artery in three patients and on radiculopial arteries in two patients; one patient harbored two lesions. Treatment consisted of superselective bucrylate embolization of the branches harboring the aneurysms, with preservation of the arterial axis. Follow-up angiograms were obtained at 3 to 6 months postembolization in all patients. All patients presented with hemorrhagic events. Hematomyelia was clearly related to a sulcocommissural or a vasa corona aneutrysm in two patients. Another sulcocommissural aneurysm and multiple radiculopial aneurysms were presumed to be the cause of subarachnoid hemorrhage in two other patients. One patient harbored aneurysms on a sulcocommissural artery and on a radiculopial artery. All aneurysms were permanently obliterated. In one patient with a single fistula, the SCAVM was cured. The SCAVM was only partially obliterated (95, 50, and 20% in apparent volume) in three other patients. There were no complications or rebleeding episodes during a follow-up period of 17 to 37 months. Aneurysms associated with SCAVMs can be eradicated by supraselective embolization, even on the anterior spinal artery territory. For patients presenting with hemorrhage and prohibitive risk of complete resection, embolization of aneurysms may decrease the risk of further rebleeding.
Adult↗
Cerebellar infarct caused by spontaneous thrombosis of a developmental venous anomaly of the posterior fossa.
Spontaneous thrombosis of a posterior fossa developmental venous anomaly (DVA) caused a nonhemorrhagic cerebellar infarct in a 31-year-old man who also harbored a midbrain cavernous angioma. DVA thrombosis was well depicted on CT and MR studies and was proved at angiography by the demonstration of an endoluminal clot.
Adult↗
Healing mechanisms in experimental aneurysms. I. Vascular smooth muscle cells and neointima formation.
PURPOSE: The purpose of this work is to better define healing phenomena in this model, in an effort to find strategies to improve long term results of endovascular treatment. METHODS: Lateral wall venous pouch aneurysms were constructed on both carotid arteries in 30 pigs. The aneurysms were packed with collagen sponges per-operatively in 25 animals. Angiography, serial histological studies and immuno-histochemistry tests were used to study healing phenomena and measure neointima formation at various time intervals from 1 day to 9 weeks after surgery. GDC embolization was performed in 5 other pigs for comparison with the collagen sponge model. Explants from the neointima at the neck of aneurysms as well as from the parent artery of 8 pigs were prepared in an attempt to grow and to characterize in vitro cells responsible for healing porcine aneurysms using immunocytochemistry and enzymatic assays. To confirm the hypothesis that an analogy exists between cells involved in aneurysmal healing and neointimal cells found in restenosis, explant outgrowths were scored and compared to explants from intact carotid arteries and carotid arteries subjected to angioplasty in 3 other animals. In addition, to test the value of neointima measurements in quantifying results, 6 dogs were analysed to correlate the thickness of the neointima formed at the neck of aneurysms with angiographic results in animals prone to recurrences. RESULTS: Histopathological findings with collagen sponge packing were similar to the ones following coil embolization. Porcine aneurysms had a strong tendency to heal with a thick neointima primarily composed of vascular smooth muscle cells (VSMCs). Aneurysms in dogs did not heal as well and the neointima at the neck of treated lesions was thin. Cells responsible for healing of experimental porcine aneurysms could be cultured in vitro, and are activated VSMCs. These cells, similar to those harvested following balloon injury, had a higher colony forming capacity and an accelerated explant outgrowth rate as compared to cells derived from the parent artery. CONCLUSION: Animals which heal poorly harbor a thin or deficient neointima at the neck of treated aneurysms. Favorable healing in porcine aneurysms involves VSMCs which form a thick neointima. These VSMCs can be cultured in vitro. They share similar outgrowth characteristics with VSMCs recovered after balloon angioplasty. The collagen sponge model may be useful to harvest cells for in vitro experimentation and in the in vivo evaluation of the local delivery of potential therapeutic molecules thought to improve healing following embolization of aneurysms.
Aneurysm↗
Juvenile nasopharyngeal angiofibroma.
This is a retrospective study of 17 patients with juvenile nasopharyngeal angiofibroma treated from 1983 to 1996. Patients with Stage I or II disease according to the Fisch classification system were treated surgically by a transpalatal approach. One patient underwent a Le Fort I osteotomy and down-fracture approach for access. Three patients underwent combined transpalatal and lateral rhinotomy for access, whereas one underwent a transcervical double mandibular osteotomy to facilitate the exposure. A patient with Stage IV disease underwent a combined subcranial frontonasal osteotomy plus a Le Fort I osteotomy for access to a massive angiofibroma. Initial surgical management prevented recurrence in 79% of patients. Two patients with intracranial extension were treated with primary irradiation therapy; their tumours became asymptomatic. Preoperative angiography and embolization were used to treat all surgical candidates. The use of newer craniofacial or subcranial techniques and infratemporal fossa approaches with osteotomies can provide access to large angiofibromas even when there is skull base or intracranial involvement. Surgical exposure may also be enhanced by the use of the Le Fort I osteotomy and down-fracture approaches.
Adolescent↗
Healing of experimental aneurysms. II: Platelet extracts can increase the thickness of the neointima at the neck of treated aneurysms.
PURPOSE: To assess the effect of platelet extracts (PE) on neointima formation following gelfoam packing of experimental porcine aneurysms. A strategy involving the local delivery of platelet growth factors may potentially improve long term results of endovascular treatment of aneurysms. METHODS: Bilateral lateral wall common carotid aneurysms were constructed on 30 pigs. A collagen sponge containing a PE rich in growth factors was used to pack one aneurysm with the controlateral lesion being embolized with a sponge containing NaCl 0.9% (22 animals). In 8 animals, a control sponge was used on both sides. Animals were sacrificed at 1, 2, 3, 4 and 9 weeks and the thickness of the neointima covering the neck of PE-treated aneurysms was measured in 5 locations for each lesion at 2 and 3 weeks and compared with the control aneurysm of the same animal. Morphometric data was analysed using the paired Student's t-test. RESULTS: The thickness of the neointima was significantly increased in lesions treated with PE as compared to control lesions at 2 weeks (p = 0.008, n = 9). There was no significant difference at 3 weeks (p = 0.99, n = 9). There was no significant difference between lesions of control animals (p = 0.95, n = 8). CONCLUSION: PE rich in growth factors can increase the thickness of the neointima at the neck of treated experimental porcine aneurysms at 2 weeks, but had no effect at 3 weeks. This accelerated neointimal formation may have some value in improving healing following endovascular treatment. This hypothesis could not be supported with this experimental model which has a spontaneous tendency to heal. Further studies using an animal model which reproduces the clinical problem of recurrences may help to define the role of the local delivery of growth factors in combination with coils in a strategy designed to improve results of endovascular treatment.
Aneurysm↗