Biomedical subjects

G Ponsot

Publications and source records attributed to G Ponsot.

At least 91 records · Page 5Linked to original sources

PubMed1991

Cerebral lymphoma and HIV encephalitis in a case of paediatric AIDS, with pre-existing multicystic encephalomalacia.

A case of intracerebral malignant B cell lymphoma associated with encephalitis typical of Human Immunodeficiency Virus (HIV) infection is described in a 4 year old child, with post-transfusion Acquired Immune Deficiency Syndrome (AIDS) and severe pre-existing cystic encephalomalacia. This report further documents B cell lymphoma as the commonest cause of an intracerebral mass, and an important cause of death in paediatric AIDS. That more than one pathological process may be responsible for neurological symptoms in paediatric AIDS is also emphasised.

AIDS Dementia Complex↗

PubMed1991

Physical exercise and voluntary hyperventilation in childhood absence epilepsy.

The aim of this study was to compare the effects of a physical exercise test and of voluntary hyperventilation between controls and children with absence epilepsy. Eighteen children (6 controls and 12 epileptics) were studied during rest (R), a maximal physical exercise test (15 min; PE), recovery (REC) and voluntary hyperventilation (3 min; VHPV). EEG and ECG were recorded during the experiment; respiratory parameters were measured to quantify PE; plasma levels of pH, lactate, pyruvate, glucose and antiepileptic drugs were determined. A decrease in the number of absences was observed during PE whereas an increase was observed during VHPV. We found significant positive correlations between the number of children with absences, the total number of absences for each state, frequency of absences per minute and the corresponding mean plasma pH, which demonstrate that the lower the pH is, the fewer absences occur. On the other hand, there was no relationship between the number of absences and the values of other parameters. Relations between variations of the plasma value of the pH, and thus the probable cerebral value of pH, and neuronal excitability are discussed. Our results indicate that children who suffer absence epilepsy should not be discouraged from sport practice.

Adolescent↗

PubMed1991

Deletions of mitochondrial DNA in Kearns-Sayre syndrome and ocular myopathies: genetic, biochemical and morphological studies.

Genetic, biochemical and morphological investigations were conducted on skeletal muscle mitochondria from 6 cases of ocular myopathy: 4 cases with Kearns-Sayre syndrome (KSS) and 2 with chronic progressive external ophthalmoplegia. All of these 6 cases showed mitochondrial DNA (mtDNA) deletions in addition to normal sized DNA in the quadriceps muscle. The deletions ranging from 3 to 8 kbp were also mapped between nucleotides 5500 and 16000 by Southern blot. The deleted genes encoded for some subunits of complexes I, IV, V and 5-10 tRNAS. The boundaries of the deletions have been sequenced in three patients. Five patients had mitochondrial respiratory chain deficiency in complex I as shown by the low oxygen consumption in isolated mitochondria using three NAD(+)-linked substrates. Mitochondria with an abnormal ultrastructure were also observed in 2 cases. A good relationship between the cytochrome c oxidase deficiency and the amount of deleted mtDNA was shown in our present investigations.

Adult↗

PubMed1991

Bilateral porencephalic defect in a newborn after injection of benzol during pregnancy.

Porencephaly is usually considered to be a prenatal brain lesion due to a circulatory failure. We report a case of bilateral porencephaly with heterotopia and absence of the septum pellucidum in a newborn. The mother had received several injections of benzol during pregnancy with an intent of inducing abortion. The possibility of a causal relationship between the administration of benzol and the occurrence of the defect is supported by the existence of previously reported cases of cerebral malformations following maternal exposure to organic solvents.

Abnormalities, Drug-Induced↗

PubMed1991

Diffuse cortical dysplasia, or the 'double cortex' syndrome: the clinical and epileptic spectrum in 10 patients.

Diffuse neuronal migration disorders associated with epilepsy can now be recognized by modern neuroimaging techniques, particularly high-resolution MRI. We report 10 patients with a recently described MRI picture of continuous or generalized band heterotopia underlying the cortical mantle, giving the appearance of a "double cortex." They have epilepsy, and almost all have mental retardation. The epileptic disorder varies in nature and degree of severity. Patients may present with infantile spasms, a Lennox-Gastaut syndrome, or other forms of secondary generalized or multifocal epilepsy. Response to medical treatment is variable. Callosotomy may lead to considerable reduction of drop attacks, present in 60%. Mental retardation is usually mild or moderate, and only rarely severe. It correlates with the type of epileptic syndrome, and is greater in patients with more disorganized cortex overlying the heterotopia. Recognition of this entity by MRI is important for appropriate diagnosis of the epileptic disorder, planning of therapeutic strategy, and prognosis.

Adolescent↗

PubMed1991

[Mitochondrial diseases].

The authors describe the main characteristics of the mitochondria. These features are essential in order to understand the clinical phenotype and the biochemical and genetic abnormalities of mitochondrial cytopathies.

Chromosome Aberrations↗

PubMed1991

[Mitochondrial function and mitochondrial DNA in a series of 64 patients suspected of having mitochondrial myopathy].

Biochemical results concerning 64 patients suspected of mitochondrial myopathies are presented. Four clinical groups were studied including 21 encephalomyopathies, 42 ocular myopathies, 8 isolated myopathies and 3 cardiomyopathies. In 26 cases, the coexistence of a normal mitochondrial DNA and a mutated mitochondrial DNA (heteroplasmy) was found (19 simple deletions, 4 multiple deletions and 3 punctual mutations) and all cases presented with ocular disorders (excepted 2 cases with MERRF). Furthermore, 1 complex I deficiency (1 ocular myopathy), 1 complex IV deficiency (1 adult encephalomyopathy type Leigh), 3 complexes I + IV deficiencies (2 cases with a cardiomyopathy and 1 familial MELAS) and 2 pyruvate (1 adult from of Leigh's encephalomyopathy) dehydrogenase deficiencies (clinically and genetically different) did not show evidence of mitochondrial DNA mutation.

Blotting, Western↗

PubMed1991

[Congenital hereditary motor and sensory neuropathy].

The authors report 6 cases of hereditary sensorimotor neuropathy (HSMN) presenting with the following clinical features: (1) severe outcome (3 out of 6 patients died before the age of 4 years), and (2) intellectual impairment (3 out of 6 cases). Histopathological study of nerve biopsies gave heterogeneous results: there was one case of axonal neuropathy (HSMN II of Dyck and Lambert), one case of demyelinating neuropathy with Schwann's cell proliferation (HSMN III of Dyck and Lambert), and one case of giant axonal neuropathy. The last three cases displayed an original pattern hitherto unknown in classical delayed HSMN, with complete disappearance of myelinated sheaths and Schwann's cell proliferation. This particular pattern did not seem to be due to the biopsy being performed at an early stage, since in one case a second biopsy showed the same histological features.

Female↗

PubMed1990

Reversible hearing loss in a patient with cryptococcosis.

A 16-year-old girl had hearing loss, paroxysmal tremor, gait disorders, and psychiatric disturbances as the initial manifestations of a cryptococcal meningoencephalitis. Imaging demonstrated an obstructive hydrocephalus, and neuro-otological explorations showed a retrocochlear deafness and diffuse brainstem involvement. Emphasis is on the deafness, which rarely occurs as a presenting symptom in this condition, and on its dramatic improvement following antimycotic therapy.

Adolescent↗

PubMed1990

Kearns-sayre syndrome. Two clinico-pathological cases.

Two clinico-pathological cases of Kearns-Sayre syndrome are reported. In both cases the typical triad (progressive external ophthalmoplegia, heart block, retinitis pigmentosa) was present and spongiosis was the main pathological finding. In one case there was also a marked capillary proliferation, significance of which is discussed. A deletion of the mitochondrial DNA was found in the muscle, spinal cord and brain of this last case.

Adolescent↗

PubMed1990

[Joubert's syndrome].

We report a new case of pathologically documented Joubert syndrome. A review of 35 published cases showed that this syndrome, first described by Joubert and Eisenring in 1969, is well individualized and exhibits consistent features, including attacks of tachypnea alternating with respiratory pauses, abnormal ocular movements, severe psychomotor retardation, and ataxia. Anatomic anomalies include vermian agenesis with cystic dilatation of the fourth ventricle. Inheritance of this condition is autosomal and recessive. Onset is in the neonatal period and prognosis is severe. Significant anatomic resemblances with the Dandy-Walker syndrome exist, although genetic and clinical features are different. The origin of this syndrome is unknown, but a study of peroxisomes is required since three cases of Joubert syndrome with pipecolic acidemia have been reported and resemblances exist between some recognized peroxisomal diseases and Joubert syndrome.

Cerebral Ventricles↗

PubMed1990

[Delayed acute measles encephalitis].

Delayed acute encephalitis is a rare complication of measles that may occur either in immunodepressed patients or in patients without overt immunodepression. In the present series of 8 cases, diagnosis was made on CSF/serum measles antibody titre and/or intranuclear paramyxovirus nucleocapsides identified by electron microscopy in the central nervous system cells. The disease is characterized by the association of focal defects (monoparesis, hemiparesis, aphasia, a.s.o.) with periodic myoclonic jerks without major impairment of consciousness. The encephalitis lasted 2 to 4 weeks and 3 patients died. With the exception of 1 case, all the patients had severe sequelae after a follow-up of 1 to 9 years. The EEG showed diffuse polymorphous delta waves, with a predominance on the side opposite to the myoclonias and pseudoperiodic complexes in all cases. CT scan was abnormal in 4 of 6 cases, showing hypodense areas. Antiviral or immunogenic therapeutic trials were administered to 5 patients without clear improvement. Sensitive methods of antibody dosage seem to be useful for the early diagnosis of the disease.

Acute Disease↗

PubMed1989

Mapping of heteroplasmic mitochondrial DNA deletions in Kearns-Sayre syndrome.

Kearns-Sayre syndrome (KSS) is a progressive neuromuscular disease characterised by ophtalmoplegia, cardiac bloc branch, pigmentary retinopathy associated with abnormal mitochondrial function. We have studied the mitochondrial DNA organization of patients presenting KSS and have found large deletions ranging from 3 to 8.5 kilobase pairs. DNA molecules containing deletion are accompanied by the presence of the normal sized mtDNA molecule forming heteroplasmic genomes. The deletions always map in the region which is potentially single stranded during mitochondrial DNA replication. The deletions differ in length and position between individuals but are similar within the different tissues of an individual suggesting that they arise during or before embryogenesis.

Biopsy↗

PubMed1989

Immunohistochemical analysis of brain macrophages in adrenoleukodystrophy.

Using a panel of monoclonal antibodies directed against antigenic determinants present at the surface of mononuclear cells, we characterized the macrophage infiltration in frozen brain specimens from a patient with adrenoleukodystrophy by immunohistochemical staining. This study demonstrated that macrophages were the main infiltrating cells in the white matter and that there was a wide variability in their phenotype according to their location: they stained very strongly with Leu-M5, EBM11, Leu-M3, To5 and 2LPM 19 C in the perivascular cuffs, whereas they stained principally with Leu-M5 and EBM11 and to a lesser extent with To5 and 2LPM19c in the white matter. In addition to the expression of MHC class II and CD4 molecules, macrophages exhibited strong labelling with 7G7B6, a monoclonal antibody raised against IL2 receptors. These results attest that macrophages, which infiltrate the brain parenchyma have various phenotypes, and very likely different states of activation, and suggest that interleukin-2 plays an important role during this activation.

Adrenoleukodystrophy↗

PubMed1989

[Nucleotide mapping and a kinetic model of a heteroplasmic deletion of 4,666 base pairs from mitochondrial DNA in the Kearns-Sayre syndrome].

We report the nucleotidic mapping of a 4,666 base pairs deletion of the human mitochondrial DNA localized at positions 8571 and 13237 in a Kearns-Sayre syndrome patient. The gene fusion between the 15 N terminal amino acid residues of ATP synthetase subunit 6 and the 303 C terminal aminoacids of NADH dehydrogenase yields a potential protein of 35,000 d MW called A6-ND5. Deletion boundaries show a short inverted repeat ATCXTA. The heteroplasmic deletion mechanism is discussed in view of these data.

Amino Acid Sequence↗

PubMed1989

[Post-transfusion cerebrovascular hemorrhagic complications disclosing homozygote sickle cell anemia].

A case of bipolar and relapsing cerebrovascular hemorrhages with hypertension is reported in a 7 year-old Gabonese girl. These strokes were the first sign of a sickle cell disease. Mechanisms of cerebral hemorrhages in sickle cell disease are reviewed and similarities with the "hypertension, convulsion and cerebral hemorrhage after transfusions "syndrome reported by Wasi et al. in thalassemic patients are underlined.

Anemia, Sickle Cell↗

PubMed1989

[Giant axonal neuropathy: intermediate filament disease with involvement of the peripheral and central nervous system].

We report a case of giant axonal neuropathy in a 14 year-old turkish boy with progressive chronic neuropathy and central involvement with mental retardation. CT showed a low density and MRI imaging multiple cavities and hypersignals of the white matter. Nerve and skin biopsies revealed an accumulation of neurofilaments in axonal swellings and an accumulation of intermediate filaments in fibroblasts, Schwann cells, endothelial cells. These findings are in accordance with the reported cases. Giant axonal neuropathy results from a generalized disorder of the intermediate filaments, but the precise biochemical defect is unknown. We would agree with Maia (1988) to name this affection "Giant Axonal Disease".

Axons↗

PubMed1989

Electroencephalographic aspects of hemimegalencephaly.

The authors retrospectively studied the electroencephalograms (EEGs) of 12 patients with hemimegalencephaly-a unilateral brain malformation which is often overlooked, despite having typical CT-scan and MRI aspects. They were characterized by three types of abnormal tracing, which correlated with prognosis: triphasic complexes of large amplitude were observed in patients with the earliest onset of seizures, and were associated with the most severe prognosis; unilateral, rhythmic 'alpha-like' activity was recorded in patients with seizures occurring after three months of age, and was associated with a relatively favourable outcome; asymmetrical suppression-bursts characterised by 'alpha-like' activity on the abnormal side were seen in patients with infantile spasms. The EEG pattern seems to make an important contribution to both diagnosis and prognosis.

Brain↗