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Biomedical subjects

M Tardieu

Publications and source records attributed to M Tardieu.

At least 127 records · Page 7Linked to original sources
PubMed1992

Human immunodeficiency virus type 1-infected monocytic cells can destroy human neural cells after cell-to-cell adhesion.

Primary cultures of human embryonic neurons and astrocytes have been used to test the interactions between neural cells and either human immunodeficiency virus type 1 (HIV-1) or HIV-1-infected monocytes. After direct infection with HIV-1, neither morphological alteration of neurons and astrocytes nor signs of viral replication were observed. Similarly, cultured human neurons and astrocytes were resistant to incubation with the supernatant of HIV-1-infected U937 cells, a human monoblastoid cell line. In contrast, HIV-1-infected U937 monocytic cells adhered to neural cells and induced large plaques of necrosis surrounding them. This cytopathic effect began at the time of viral replication (day 16 after infection). Its intensity depended on that of viral replication, and its range was identical to the region of diffusion of viral antigens, as judged by immunocytochemistry. The cytopathic effect was not dependent on the release of free radicals. It could not be induced by cytokines or cytokine-stimulated U937 cells. It is likely that this cytopathic effect depends on the release of viral antigens either within the site of adherence itself or within close range of the astrocyte membrane.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Derivatized dextrans mimic heparin as stabilizers, potentiators, and protectors of acidic or basic FGF.

Acidic and basic fibroblast growth factors (aFGF and bFGF) belong to a family of structurally related polypeptides characterized by a high affinity for heparin. a and bFGF display mitogenic activity for many cell types. Biological activity is strongly potentiated by heparin which stabilizes their molecular conformation by preventing physicochemical or enzymatic degradation. In our previous study we have shown that a water-soluble derivatized dextran named DDE, containing 82.2% methyl carboxylic acid groups, 6.1% benzylamide, and 5.6% sulfonate with a specific anticoagulant activity equivalent to heparin of 0.5 IU/mg could potentiate the mitogenic activity of aFGF on CCL39 cells. Optimal concentrations for maximal potentiation of 400 micrograms/ml and 20 micrograms/ml were obtained respectively for DDE and heparin. In the present report, we have uncovered the fact that several carboxymethyl benzylamide sulfonate dextrans differing in degree and positioning of the substituent groups can mimic heparin in regard to the protection, stabilization, and potentiating effects with aFGF or bFGF. Our data establishes that the dextran derivatives studied can act as potentiating agents for FGFs. Native dextran (DDA) had no effect. Dextran derivatives can also protect aFGF and bFGF from heat as well as from pH denaturation, and against trypsic and chymotrypsic degradation. The dextran derivative DDI (82% methylcarboxylic acid, 23% benzylamide, 13% sulfonate) was studied in greater detail and exhibited a greater protection for bFGF and a lesser protecting effect for aFGF than heparin. Derivatized dextrans which have very weak anticoagulant activity are of great interest as alternatives to heparin for use as stabilizers, potentiators, protectants, and slow-release matrices for FGFs in pharmaceutical formulations.

Animals↗
PubMed1992

Hydrodynamics in vein of Galen malformations.

Forty-three patients with vein of Galen aneurysmal malformations (VGAM) referred to us for endovascular treatment between 1985 and 1990 and 335 additional cases published in the literature were reviewed with particular attention to the presence of ventricular enlargement and outcome after shunting. Hydrocephalus was the second most frequent symptom (46.8%); it is more frequent in infants (73%) than in children, adults (30%) or neonates (15%). Of the patients reported in the literature, 17.9% had undergone shunting. Within the shunted population there was an overall morbidity of 41% and a mortality of 10% (especially in the infant group). In our series 17 patients (39.5%) were shunted and a significant difference in the clinical outcome was noted between the shunted and the nonshunted group. Of the nonshunted patients, 66.6% were free of any neurological deficit or mental retardation and fewer than 5% presented with significant mental retardation. On the other hand, only 33.3% of the shunted patients had a favorable outcome and more than 15% developed significant mental retardation. Among the various causes of hydrocephalus in patients with VGAMs, such as obstruction of the aqueduct, subarachnoid hemorrhage, or ex vacuo hydrocephalus, high venous pressure may be of particular importance. In this article a physiopathological interpretation of the hydrodynamics in VGAMs is developed and a speculative explanation for CSF disorders related to ventricular shunting proposed. Treatment of hydrocephalus in VGAMs can be achieved through obliteration of the malformation or at least diminishing the venous pressure; surgical ventricular shunting does not have to be the first treatment of hydrodynamic disorders associated with VGAMs, especially in infants.

Brain Damage, Chronic↗
PubMed1992

Coma associated with intense bursts of abnormal movements and long-lasting cognitive disturbances: an acute encephalopathy of obscure origin.

We report six previously healthy children who several days after a prodromal illness had an acute encephalopathy that ran a biphasic course. It appears to constitute a recognizable syndrome with a good prognosis that can be differentiated from other encephalopathies of obscure origin as previously defined by Lyon et al. The active phase was dominated by coma or confusion and by abnormal movements, including disordered gesticulation and attacks of orofacial dyskinesia or limb dystonia associated with permanent rigidity and culminating in opisthotonic posturing. Repeated seizures were observed in only two patients. Permanent slow waves were recorded on the electroencephalogram in all patients, even during bursts of abnormal movements. Cerebrospinal fluid and results of serologic studies were normal throughout the course of the disease, and attempts at viral isolation and antiviral antibody detection yielded negative results. Brain imaging either showed no abnormalities or suggested a moderate degree of brain edema. The recovery phase, which extended for several weeks, was characterized by a rapid return of motor function and persistent behavioral and cognitive disturbances. Nonverbal reasoning recovered long before verbal expression returned to normal. Four patients eventually recovered fully, whereas two had mild sequelae.

Acute Disease↗
PubMed1992

Enhanced tumor necrosis factor alpha in coronavirus but not in paracetamol-induced acute hepatic necrosis in mice.

Previous reports have demonstrated that tumor necrosis factor alpha (TNF-alpha) plays an important role in the pathogenesis of fulminant hepatic necrosis. The purpose of this experimental study was to measure TNF-alpha blood activity in paracetamol-induced liver necrosis and in coronavirus (MHV3)-induced fulminant hepatitis in mice. No elevation of TNF-alpha activity was found in hepatic failure complicating paracetamol poisoning. In contrast, TNF-alpha activity significantly increased in response to MHV3, reaching 16.3 +/- 5.5 U/ml from 24 h post infection (P less than 0.01). This augmentation was observed even though the virus was not detectable in the liver. Serum alanine aminotransferase levels were low and no histological lesion was observed. In conclusion, our study further supports the implication of TNF-alpha in virus-induced hepatitis failure and confirms that paracetamol poisoning does not cause increased TNF-alpha activity in the circulation.

Acetaminophen↗
PubMed1992

Extracellular matrix covered biomaterials for human endothelial cell growth.

The aim of this study is to optimize conditions for growing endothelial cells on vascular biomaterials. Bovine cornea endothelial cells (BCEC), stimulated by basic Fibroblast Growth Factor (bFGF) secrete an extracellular matrix (ECM) similar to the Descemet membrane produced in vivo by these cells. This ECM, obtained by removing BCEC with an hypotonic shock can be used as a substratum for other endothelial cell growth. Human endothelial cells (HEC) were purified from omentum that was digested with a solution of collagenase-dispase, then filtered through nylon meshes. The cells were further purified by centrifugation onto a Percoll gradient. A comparative study on the attachment and growth of HEC on various coatings (laminin, poly-L-lysine, fibronectin or ECM) indicates that ECM is the most performing substratum. The quality of this endothelium was confirmed by the presence of factor VIII, and MHC class I and the absence of class II antigens.

Animals↗
PubMed1992

Natural history of human immunodeficiency virus type 1 infection in children: prognostic value of laboratory tests on the bimodal progression of the disease.

This study analyzes the correlation of basic laboratory test results with clinical outcome in 94 children with perinatally acquired human immunodeficiency virus 1 infection who did not receive zidovudine during the study period of 1983 to 1988. Two life-threatening conditions highly correlated with survival, opportunistic infection and severe encephalopathy, were the end points of the study. At a median age of 25 months 30 (32%) of the 94 children had developed such conditions (Group I), and their survival at 3 years of age was 48% (95% confidence interval, 24 to 72%), contrasting with the 97% survival rate (95% confidence interval, 94 to 100%) of the remaining 64 (68%) children who had not developed such conditions by age 25 months. (Group II). Compared with children in Group II, children with life-threatening complications were more likely at the onset of symptoms to be younger and have a lower CD4 count, an impaired in vitro lymphocytic proliferation and a lack of p18 or p25 antibodies in the Western blot profile and, during the progression of the disease, a negative slope of the subsequent CD4 counts. These results highlight the need for an early diagnosis of the human immunodeficiency virus 1 infection in children and demonstrate that it is possible to determine the prognosis of their disease as early as in the first year of life.

Child, Preschool↗
PubMed1992

Low levels of human immunodeficiency virus replication in the brain tissue of children with severe acquired immunodeficiency syndrome encephalopathy.

The authors examined the autopsy brain samples of nine children infected with human immunodeficiency virus (HIV) at birth by histology, immunologic staining, and in situ hybridization. Surprisingly, although seven of these children presented with typical AIDS encephalopathy, the authors could detect a multifocal HIV infection in the brains of only three of these patients. The authors could not detect any significant HIV replication in the brain of four other children despite severe neurologic disease. However, HIV DNA was detected by polymerase chain reaction (PCR) in the central nervous system (CNS) of all patients. In addition, the authors found associated lesions in the brains of three of these four patients. This study shows that severe AIDS encephalopathy exists in children and therefore might exist in adults with few signs or without any signs of HIV replication or inflammation in the CNS. Understanding the pathogenesis of this neurologic disease and the kinetics of HIV replication in brain tissue of children with AIDS encephalopathy is essential to determine the best therapeutic strategy.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Rett syndrome].

Explore the source record for details and available documents.

Humans↗
PubMed1991

Human microglial cells: characterization in cerebral tissue and in primary culture, and study of their susceptibility to HIV-1 infection.

Neuropathological studies have shown that human immunodeficiency virus type 1-infected cells within the brain express several markers characteristic of macrophages and could either be microglial cells, or monocytes invading the CNS, or both. To better define the target cells of human immunodeficiency virus type 1 within the brain, we have studied human microglial cells, both in vivo and in vitro, and compared them to monocytes for their antigenic markers and their susceptibility to human immunodeficiency virus type 1 infection. Brain-derived macrophages were isolated from primary cortical and spinal cord cultures obtained from 8 to 12-week-old human embryos. The isolated cells presented esterase activity, phagocyted zymosan particles, expressed several (Fc receptors, and CD68/Ki-M7 and CD11b/CR3 receptors) of the macrophagic antigenic markers, and appeared to be resident microglial cells from human embryonic brain. Conversely, brain-derived macrophages did not express antigens CD4, CD14, or CD68/Ki-M6, which are easily detected on freshly isolated monocytes. Using these antigenic differences between isolated microglial cells and monocytes, we have observed that two populations of macrophages could be individualized. In the normal adult brain, microglial cells were numerous in both the gray and the white matter. The infrequent cells sharing antigens with monocytes were found almost exclusively around vessels. In 8 to 12-week-old human embryos, microglial cells were found in both the parenchyma and the germinative layer. Cells sharing antigens with monocytes were only found at the top of and inside the germinative layer. In brain tissue from patients with human immunodeficiency virus type 1 encephalitis, cells sharing antigens with monocytes are abundant not only around the vessels but also in the parenchyma. In double-labeling experiments, human immunodeficiency virus type 1-infected cells showed monocyte antigens. Finally, microglial cells also differ from monocytes in their in vitro susceptibility to human immunodeficiency virus type 1 infection; after stimulation by r-TNF alpha or GmCSF, monocytes but not microglial cells can replicate human immunodeficiency virus type 1. This in vitro difference in human immunodeficiency virus type 1 susceptibility between monocytes and microglial cells together with the presence of monocytic antigens within the brain tissue of human immunodeficiency virus type 1-infected patients suggest that human immunodeficiency virus type 1-infected cells within the brain are either monocytes that have crossed the blood-brain barrier and spread through the tissue or perivascular microglial cells that, after phagocyting infected blood lymphocytes, subsequently contain viral antigen and migrate to brain tissue.

Brain↗
PubMed1991

Vein of Galen malformation. Endovascular management of 43 cases.

Since 1984, 43 patients with true vein of Galen aneurysmal malformations have been referred to us and managed according to our patient selection, technique, and follow-up guidelines. Thirty-four were embolized transarterially with bucrilate (isobutyl cyanoacrylate) or enbucrilate (N-butyl cyanoacrylate) embolization. No cutdown or hypotension during or after the embolization was used and no balloon catheter was employed. Forty-seven percent of the children had a completely occluded lesion which was confirmed when the child was at least 6 months of age at the follow-up angiographic examination; 52.9% were found to be completely normal or only to have mild cardiac failure that could be treated medically or moderate macrocephaly without neurological symptoms or mental retardation. In the embolized group 5.8% died as a result of the wrong treatment (1 case) or poor timing of embolization 3 days after ventricular shunting (1 case). The overall mortality (embolized and non-embolized groups) in the neonatal children was 27.7% with a total of 18.6% for all ages. Complete morphological exclusion of the arteriovenous malformation was accomplished in 41.9%; 74.4% of all children referred are now clinically normal or present moderate mental retardation which is diminishing. There was 3% neurological morbidity in the embolized group (only following the venous approach) in 78 sessions and more than 100 arteries embolized. These results compare favorably with surgical or other techniques of arterial embolization (balloon or particles), as well as transvenous (transtorcular or transfemoral) embolization, where the morbidity and mortality are significantly higher and the late clinical evaluation is seldom satisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Atypical electroencephalographic activity in terminal phase subacute sclerosing panencephalitis].

The authors describe the evolution of the EEG during a 3-yr period in a case of subacute sclerosing panencephalitis (SSPE) revealed by epilepsy in a 9 yr-old boy. During the first 2 yr, the EEG was markedly abnormal (diffuse spike-waves, delta rhythms). During the static period, it looked like a continuous non-convulsive status epilepticus. The typical periodic abnormal activity only appeared at the terminal stage, and after a Valium test. Then slow wave complexes persisted on a dysrhythmic background. This type of EEG has never been described; our study stressed the efficacy of the Valium test in this particular case.

Child↗
PubMed1991

Low-dose zidovudine in children with an human immunodeficiency virus type 1 infection acquired in the perinatal period.

This report describes the one-year results of a noncomparative study designed to assess the safety and tolerance of low-dose zidovudine (azidothymidine) given orally to 60 human immunodeficiency virus type 1-infected infants and children. At baseline, the mean age was 1.9 years (+/- 1.4), and all were symptomatic: 43% were P2A and 57% were P2B to F according to the Centers for Disease Control classification. All the patients received zidovudine for at least 6 months, and 52 of them (87%) completed a full year of therapy. The mean duration of follow-up was 346 days (+/- 42) (range, 183 to 366 days). The initial therapy consisted of four daily doses of 100 mg/m2 (400 mg/m2 per day, equivalent to 20 mg/kg per day). However, this treatment was modified when neutropenia or anemia was observed. Twenty-nine children (48%) remained at the initial therapy for the entire study. Zidovudine dosage was adjusted 92 times in the other 31 children (52%), mostly due to neutropenia (83%). Altogether, the time under full-dose therapy represented 81% of the total duration of the protocol for all patients. Children with mild symptoms, P2A at study entry, were more likely to remain under full-dose therapy than children with severe symptoms, P2B to F: the time under full-dose therapy represented 91% of the duration of the protocol for the former group and only 74% for the latter one (P less than .02). No clinical adverse experiences were attributed directly to zidovudine. Thirty-seven children were prescribed trimethoprim-sulfametoxazole as a prophylaxis for Pneumocystis carinii pneumonia.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1991

Autosomal dominant deletions of the mitochondrial genome in a case of progressive encephalomyopathy.

Multiple deletions of the mitochondrial genome were found in a family in which the proband had ataxia and ketoacidotic comas. A progressive multiorgan involvement appeared in the course of the disease, and histopathological investigation demonstrated mitochondrial myopathy features with ragged red fibers. A defect of oxidative phosphorylation was found in both skeletal muscle and lymphocytes. It is surprising that various mtDNA deletions were detected both in the proband and in his healthy mother and maternal aunt but not in the rest of the maternal progeny. All the deletions were located between Cox II and cytochrome b genes, and short (4-5 bp) repeated sequences were consistently present at the boundaries of the rearrangements in different tissues. Therefore, the deletions appear not to be transmitted per se but to be inherited in a Mendelian manner, being possibly dominant. Both the Mendelian inheritance of the trait and the variety of the deletions in carriers suggest that a nuclearly encoded factor(s) might be involved in the triggering of the deletions. However, the presence of the rearrangements in healthy individuals raises the question of whether mtDNA deletions actually cause the clinical expression of the disease.

Base Sequence↗
PubMed1990

Longitudinal study of 94 symptomatic infants with perinatally acquired human immunodeficiency virus infection. Evidence for a bimodal expression of clinical and biological symptoms.

To better define the clinical and biological evolution of infants after vertical human immunodeficiency virus type 1 infection, we analyzed 94 consecutive infected patients followed up after their first clinical symptoms. The expression of clinical symptoms and biological abnormalities followed a bimodal distribution, some patients having an early and severe disease and the others having a slowly progressive one. One third of our patients suffered from early onset of opportunistic infection (OI). These patients had a significantly higher incidence of severe encephalopathy compared with patients without OI. The rate of survival at 3 years was 48% +/- 24%. In contrast, the patients without early OI or severe encephalopathy had a probability of survival at 3 years of 97% +/- 3%. This probability was not modified by the occurrence of bacterial infection or lymphoid interstitial pneumonitis. Lymphoid interstitial pneumonitis occurred at a mean age of 29 months, significantly later than OI or severe encephalopathy. Laboratory results at initial examination were correlated with clinical symptoms. Thus, when the number of CD4 lymphocytes was less than 500/mm3, children suffered more frequently from life-threatening symptoms (OI and severe encephalopathy): 15 of 22 vs 14 of 69. The same was true when the lymphocytes did not proliferate after antigenic stimulation, when anti-p18 and/or anti-p25 antibodies were absent in the serum, and when p24 antigen was detected in serum. Finally, severe encephalopathy was associated with low anti-human immunodeficiency virus cerebrospinal fluid antibody titer, whereas 88% of patients with moderate or no encephalopathy had signs of intrathecal anti-human immunodeficiency virus antibody synthesis. In conclusion, a subgroup of patients expressed very early signs of severe immunodeficiency and encephalopathy, whereas the majority of patients had a longer survival and less severe clinical symptoms during their first years of life than previously thought.

AIDS Dementia Complex↗
PubMed1990

[Prognostic evaluation of severe head injuries in children].

In 34 children overcoming a severe head injury (coma greater than 1 d, mean: 10 d), the follow-up (mean: 25 m) has been correlated with several data. 1) The quality of life, according to a 3 grade-score, is mostly dependent upon the degree of neuropsychological sequelae. By decreasing frequency were noted disturbances of: memory, intelligence (the most significantly correlated with the quality of life), attention, rapidity of performances, behaviour, visuoconstructive activities. Most often several disturbances were associated, but without systematization. 2) Correlations between general outcome and early findings: a coma greater than 10 d, a subdural collection on the CT scan at 2-6 weeks have a pejorative meaning. Age does not appear to be relevant. 3) In a sequential study of neuropsychological functions, an early evaluation is poorly predictive, except in case of rapid normalization. Evaluation at 6 months gives a good picture of the outcome. Sectorial improvements can occur beyond the 1st year but do not appear to modify dramatically the general outcome.

Adolescent↗
PubMed1990

[Encephalitis with viral replication. Clinical aspects, prognosis and treatment].

Encephalites with viral replication are due to multiplication of a virus within the central nervous system. Diagnosis and initial therapeutic decisions rest on simple clinical and paraclinical findings: age of the child, presence of high-grade fever, presence and localization of seizures, CSF characteristics, and EEG findings. Acyclovir is always indicated in a drowsy child with a high fever who has even a brief seizure and CSF abnormalities.

Adolescent↗