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Biomedical subjects

G Buisson

Publications and source records attributed to G Buisson.

At least 19 recordsLinked to original sources

Crystallization and crystal packing of Proteus mirabilis PR catalase.

The tetrameric catalase from Proteus mirabilis PR (EC 1.11.1.6), known to bind NADPH, has been crystallized by the hanging-drop method in a form apparently depleted in dinucleotide. The crystals belong to the hexagonal space group P6(2)22 with a = b = 111.7 A, c = 248.8 A. There is one subunit in the asymmetric unit. Data were collected to 2.9 A at the L.U.R.E. (Orsay) synchrotron radiation facility. The tetramers have been located in the crystal, centered on the site (1/2, 0, 0) with 222 symmetry.

Catalase

Diagnosis of HTLV-I infected seronegative neurological patients by polymerase chain reaction amplification in Martinique.

HTLV-I is a type C human retrovirus, endemic in Japan, central Africa, South America and the Caribbean, which causes adult T cell leukemia/lymphoma and chronic progressive paraparesis. Some neurological patients with chronic progressive myelopathies, but seronegative for HTLV-I have been reported in Martinique. We performed polymerase chain reaction (PCR), to look for the presence of HTLV-I genomic sequences in those patients. Two primers were chosen for gag and tax genes. Liquid hybridization was performed on the amplified products using an internal 32p labelled oligonucleotide as a probe. The hybridized material was run on a 6% polyacrylamide gel. Forty-three of forty-four seropositive subjects analysed as "positive controls" were positive for gag, but only 16/29 for tax. Twenty HTLV-I seronegative neurological patients with a symptomatology suggesting HAM/TSP were tested: 18 were found positive for at least one of the 2 oligonucleotide pairs. Two "negative controls": Moya-Moya and vascular brain failure were found negative. 8/9 subjects with uninterpretable WB were also studied by PCR, and 8 were found positive for at least one oligo pair. Our conclusion is that PCR methodology is able to detect genetic information related to HTLV-I in a number of cases where classical serology is negative.

Blotting, Western

Bronchoalveolar lymphocytosis in patients with tropical spastic paraparesis associated with human T-cell lymphotropic virus type 1 (HTLV-1). Clinical, immunologic, and cytologic studies.

STUDY OBJECTIVE: To determine the features of pulmonary involvement in patients with tropical spastic paraparesis associated with human T-cell lymphotropic virus type 1. DESIGN: Nonrandomized prospective case series. SETTING: Tertiary care units in two university medical centers. PATIENTS: Consecutive sample of 21 patients with tropical spastic paraparesis associated with human T-cell lymphotropic virus type 1 infection. INTERVENTIONS: Chest roentgenogram and bronchoalveolar lavage were done in all patients. Fifteen patients had pulmonary function tests. Alveolar T-lymphocyte subsets were analysed in 10 patients and thoracic computed tomographic scans were done in 10 patients. MEASUREMENTS AND MAIN RESULTS: All patients were free of clinical pulmonary symptoms and had normal chest roentgenograms. Thoracic computed tomographic scans were normal in 9 of 10 patients and showed mild interstitial pneumonitis in 1. Pulmonary function tests were within the normal range in 13 patients and showed a mild restrictive syndrome in 2. Eighteen patients had increased absolute numbers of alveolar lymphocytes (mean, 77 +/- 39 X 10(3) lymphocytes/mL; range, 13.5 X 10(3) to 259 X 10(3) lymphocytes/mL). Sixteen patients had percentages of alveolar lymphocytes higher than 20% of all alveolar cells (mean, 33.5 +/- 12.7; range, 9 to 69). In all 10 patients tested, 64.2% +/- 13.2% of alveolar lymphocytes were CD8+ cells. CONCLUSIONS: Excessive absolute numbers and percentages of alveolar lymphocytes were observed in 18 and 16 patients, respectively. Most alveolar lymphocytes were CD8+ cells.

Adult

HTLV-I-associated tropical spastic paraparesis in Martinique: a reappraisal.

Human T-lymphotropic virus type I (HTLV-I)-associated tropical spastic paraparesis in Martinique has been identified in 54 patients, 49 women and 5 men. This myelopathy represents an endemic problem on this island and the earliest documented case dates from 1952. A blood transfusion history was obtained in 7 of the 54 patients (13%). There was a preponderance of cases from the northern Atlantic coast of Martinique, the most humid region on the island. The prevalence in this region reached 49.5 per 100,000, compared with the global prevalence of 11.9 cases per 100,000 for the island. An immune-mediated mechanism may be important in the pathogenesis of HTLV-I-associated tropical spastic paraparesis.

Adult

[Cerebrovascular complications of sickle-cell anemia].

Cerebrovascular disorders are frequent in sickle-cell anemia. They occur mainly in homozygous children. Traditionally, they were believed to result from an arteriolar sickle-cell thrombosis, the "sludge" phenomenon, which is generally responsible for sickle cell anemia disorders. It is now well known that several other kinds of cerebral damages are involved such as moya-moya syndrome, cerebral hemorrhage, subdural hematoma, extra-dural hematoma and cerebral thrombophlebitis. In this disease, the identification of these different processes cannot be always made by a simple clinical examination. However, specific therapies are sometimes necessary, such as neurosurgical intervention in the case of aneurysm or hematoma, and, according to some authors, the necessity of repeated appropriate transfusions, in the case of moya-moya. So it is imperative to carry out without delay a complete neuroradiological assessment of the lesions. At present, the most widely accepted theory to explain the arteriolar lesions, is that they result from a sickle-cell thrombosis of the vasa-vasorum, but, we think it is not the only valid hypothesis and we think that other phenomena may be involved with a genetic factor (patients with connective tissue disorders may have a particular genotype), and with infectious or autoimmune or coagulation disorders, the latter being frequently observed in this disease.

Adolescent

Three dimensional structure of porcine pancreatic alpha-amylase at 2.9 A resolution. Role of calcium in structure and activity.

The crystal structure of porcine pancreatic alpha-amylase (PPA) has been solved at 2.9 A resolution by X-ray crystallographic methods. The enzyme contains three domains. The larger, in the N-terminal part, consists of 330 amino acid residues. This central domain has the typical parallel-stranded alpha-beta barrel structure (alpha beta)8, already found in a number of other enzymes like triose phosphate isomerase and pyruvate kinase. The C-terminal domain forms a distinct globular unit where the chain folds into an eight-stranded antiparallel beta-barrel. The third domain lies between a beta-strand and a alpha-helix of the central domain, in a position similar to those found for domain B in triose phosphate isomerase and pyruvate kinase. It is essentially composed of antiparallel beta-sheets. The active site is located in a cleft within the N-terminal central domain, at the carboxy-end of the beta-strands of the (alpha beta)8 barrel. Binding of various substrate analogues to the enzyme suggests that the amino acid residues involved in the catalytic reaction are a pair of aspartic acids. A number of other residues surround the substrate and seem to participate in its binding via hydrogen bonds and hydrophobic interactions. The 'essential' calcium ion has been located near the active site region and between two domains, each of them providing two calcium ligands. On the basis of sequence comparisons this calcium binding site is suggested to be a common structural feature of all alpha-amylases. It represents a new type of calcium-protein interaction pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Endemic tropical spastic paraparesis associated with human T-lymphotropic virus type I: a clinical and seroepidemiological study of 25 cases.

Tropical spastic paraparesis (TSP) is a common myeloneuropathy with primary and predominant involvement of the pyramidal tract and minimal sensory loss. The epidemic form of TSP is related to toxic nutritional factors, but the endemic form occurs in clusters in tropical areas, especially in India, Africa, the Seychelles, Colombia, and areas of the Caribbean. We describe the clinical and epidemiological features of 25 TSP patients from Martinique (French West Indies) with serum antibodies to human T-lymphotropic virus type I (HTLV-I). Furthermore, all 11 patients who were seropositive for HTLV-I had specific HTLV-I antibodies in their CSF. All were women. The age of onset varied from 25 to 60 years (mean, 45 years). The main clinical features are spastic paraparesis or paraplegia with spasticity of the upper limbs, minimal sensory loss, and bladder dysfunction. Minimal estimated incidence and prevalence are 1 per 100,000 inhabitants per year and 8 per 100,000, respectively. Seventeen percent of the relatives of patients with HTLV-I-associated TSP have HTLV-I antibodies (1 husband and 7 children). In Martinique, the prevalence of HTLV-I antibodies in the general population is about 2% and reaches 10% for neurological disorders other than TSP. Since our initial report, the association between spastic paraparesis and HTLV-I has been confirmed in Jamaica, Colombia, and Japan, suggesting the neurotropism of this lymphotropic human retrovirus.

Adult

[Tropical spastic paraparesis in Martinique. High prevalence of anti-HTLV-I antibodies].

Owing to the frequent occurrence in tropical countries of subacute spinal cord diseases of unknown origin, a nosological entity called tropical spastic paraparesis has been individualized. Twenty-two cases have been observed in Martinique. The presence in the serum of antibodies directed against human T-cell leukaemia/lymphoma virus (HTLV-I) in 15 of these 22 patients suggests that this lymphotropic virus or a related one might also be neurovirulent.

Adult