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Biomedical subjects

M Granier

Publications and source records attributed to M Granier.

At least 19 recordsLinked to original sources
PubMed2006

[Mild head trauma: complications and acousticovestibular sequelae].

Head injury with fracture of the petrous bone is frequent and directly related to the development of human activity. Head trauma is associated with nearly 75% of traffic accidents; 5% of them with petrous bone fracture. Based on a clinical case, the acute injuries and secondary acoustic or vestibular sequelae after low-energy cranio-cerebral trauma are discussed here. The subject was a victim of a low-energy head trauma with brief loss of consciousness and translabyrinthine fracture of the petrous bone. This fracture caused invalidating equilibrium disorders related to a perilymphatic fistula. These disorders persisted for 3.5 years and required several hospitalizations and three surgical procedures. The acoustic problems progressed towards cophosis and persistent and invalidating tintinus. We discuss the pathogenesis and treatment of these different sequelae of the middle ear as well as the external lesions. Among labyrinthine involvement, especially unilateral destruction, fistulization, concussion, and post concussion syndrome are especially descripted. Bony dislocations dominate middle ear sequelae. We also discuss the medicolegal problems associated with this type of pathology.

Adult↗
PubMed2006

Microsatellites reveal extensive geographical, ecological and genetic contacts between invasive and indigenous whitefly biotypes in an insular environment.

Human-mediated bioinvasions provide the opportunity to study the early stages of contact between formerly allopatric, divergent populations of a species. However, when invasive and resident populations are morphologically similar, it may be very difficult to assess their distribution in the field, as well as the extent of ecological overlap and genetic exchanges between invasive and resident populations. We here illustrate the use of data obtained from a set of eight microsatellite markers together with Bayesian clustering methods to document invasions in a group of major tropical pests, Bemisia tabaci, which comprises several morphologically indistinguishable biotypes with different agronomic impacts. We focus on the island of La Réunion, where an invasive biotype (B) has recently been introduced and now interacts with the resident biotype (Ms). The temporal and spatial distribution, host-plant range and genetic structure of both biotypes are investigated. We showed (i) that, without prior information, clustering methods separate two groups of individuals that can safely be identified as the B and Ms biotypes; (ii) that the B biotype has invaded all regions of the island, and showed no signs of genetic founder effect relative to the Ms biotype; (iii) that the B and Ms biotypes coexist in sympatry throughout most of their geographical ranges, although they tend to segregate into different host plants; and finally (iv) that asymmetrical and locus-specific introgression occurs between the two biotypes when they are in syntopy.

Animals↗
PubMed2005

A new silverleaf-inducing biotype Ms of Bemisia tabaci (Hemiptera: Aleyrodidae) indigenous to the islands of the south-west Indian Ocean.

Following the first detection of tomato yellow leaf curl virus (TYLCV) from Reunion (700 km east of Madagascar) in 1997 and the upsurge of Bemisia tabaci (Gennadius) on vegetable crops, two genetic types of B. tabaci were distinguished using RAPD-PCR and cytochrome oxidase I (COI) gene sequence comparisons. One type was assigned to biotype B and the other was genetically dissimilar to the populations described elsewhere and was named Ms, after the Mascarenes Archipelago. This new genetic type forms a distinct group that is sister to two other groups, one to which the B biotype is a member and one to which the Q biotype belongs. The Ms biotype is thought to be indigenous to the region as it was also detected in Mauritius, the Seychelles and Madagascar. Both B and Ms populations of B. tabaci induced silverleaf symptoms on Cucurbita sp., and were able to acquire and transmit TYLCV. Taken together these results indicate that the Ms genetic type should be considered a new biotype of B. tabaci.

Animals↗
PubMed1999

Nucleotide sequence evidence for three distinct sugarcane streak mastreviruses.

The complete sequences of four clones of sugarcane streak virus (SSV) isolates from Egypt and one SSV clone from Reunion island were determined. The four Egyptian genomes were highly similar to one another (97-99% nt identity) and were considered as variants of the same virus. The Egyptian SSV was genetically different from all other mastreviruses, the closest virus being SSV from South-Africa (60% nt identity), and defined as a new mastrevirus species named SSEV. The SSV clone from Reunion was highly related to the SSV from Mauritius and SSV from Nigeria, for which only partial sequences were available, indicating that the three sugarcane streak isolates from Mauritius, Reunion and Nigeria were strains of the same virus tentatively named SSMV. This work further confirms that SSMV is a distinct viral species compared to other mastreviruses, including the SSEV (59% nt identity) and SSV (66% nt identity). By comparing two clones from the Mascarene islands, we correlated substitutions in the C-terminal end of the coat protein with a different response to a monoclonal antibody, providing data on the mapping of a specific epitope. Agroinoculations experiments demonstrated that an SSEV clone induced more severe symptoms on maize than two clones from the Mascarene. Inside the African streak virus cluster, the sugarcane mastrevirus isolates were gathered in a sub-cluster of three viruses, SSEV, SSV and SSMV. The diversity of the SSVs is discussed in relation to its host, sugarcane, an imported crop in Africa.

Base Sequence↗
PubMed1999

[Urogenital amyloidosis: clinico-pathological study of 8 cases].

Amyloidosis of the genito-urinary tract is uncommon. We report 8 cases, often misdiagnosed as a neoplastic process (6/8). Amyloidosis was localized in the bladder (3 cases), in the ureter (1 case) and in the prostate and/or seminal vesicles (4 cases). The amyloid protein was characterized in 7 cases by immunohistochemistry. Among the bladder and ureter amyloidosis, 2 cases were classified as AL lambda amyloidosis and one case as AA amyloidosis in a patient with long history of chronic arthritis. In the fourth case, the deposits could not be identified. Nevertheless an AL amyloidosis might be suggested. Two cases of prostate and/or seminal vesicles amyloidosis were stained with an anti-B2M antibody, in hemodialyzed patients. The 2 others, positive with the anti-Transthyretina antibody, were classified as senile amyloidosis. This small series illustrated the heterogeneous pathogenic types of amyloidosis in the urogenital tract and emphasized the interest of immunohistochemistry to identify the chemical composition of these deposits.

Adult↗
PubMed1998

Quasispecies nature of three maize streak virus isolates obtained through different modes of selection from a population used to assess response to infection of maize cultivars.

Three maize streak virus (MSV) isolates were derived from an MSV population used to assess the response to infection of maize cultivars. Isolate SP1 was obtained from this population through short acquisition and inoculation periods (1 and 5 min, respectively), using a single Cicadulina mbila vector. Isolate SP2 was derived from SP1 after transmission to a wild perennial host (Coix lacryma-jobi), on which it was maintained for about 4 years without insect transmission. Isolate N2A, the most pathogenic isolate, was obtained from the initial population after serial passages on almost completely resistant inbred maize lines. The complexity of each isolate was analysed by RFLP analysis and sequencing based on 120 SP1 clones, 36 SP2 clones and 40 N2A clones. All three isolates were composed of different but related clones, consistent with a quasispecies structure. The mutations were distributed throughout the genome. Mutation frequencies, based on all available sequences, were 3.8 x 10(-4) for SP1, 10.5 x 10(-4) for SP2 and 6.9 x 10(-4) for N2A. As expected from the bottleneck selection step, the intra-isolate variability of SP1 was relatively low. Comparison between SP1 and SP2 showed that SP1 heterogeneity increased during maintenance on the wild host. Furthermore, the consensus sequences of SP1 and SP2 differed by two non-synonymous substitutions in the complementary sense gene repA. N2A had a relatively low degree of heterogeneity, but was composed of several sub-populations. The results reflect the influence of the mode of selection of MSV isolates on their quasispecies organization, i.e. distribution of variants, and master sequence.

Base Sequence↗
PubMed1996

Infectivity and complete nucleotide sequence of the genome of a genetically distinct strain of maize streak virus from Reunion Island.

A complete infectious genome of an isolate of maize streak subgroup 1 geminivirus from Reunion Island (MSV-R) was cloned and sequenced. Using an Agrobacterium tumefaciens Ti plasmid delivery system, the cloned 2.7 kb circular DNA was shown to be infectious in maize. The agroinfected virus could be transmitted by Cicadulina mbila, the most common vector species of MSV in Reunion. Analysis of open reading frames (ORFs) revealed seven potential coding regions including the 4 ORFs conserved in all geminiviruses infecting monocotyledonous plants, the 2 on the viral "+" strand (MP, CP), and the 2 on the complementary "-" strand (RepA, RepB). The nucleotide sequence of MSV-R was compared to previously determined sequence of three African clones from Nigeria (MSV-N), Kenya (MSV-K), and South Africa (MSV-S). More similarity was found between the African clones (97.0-97.3%) than between these and MSV-R (94.4-95.3%). Nucleotide substitutions were frequent in the large intergenic region, particularly in and around the most likely TATA box for the complementary sense genes, and in the 5' end of ORF V1. The comparison of the predicted peptide sequences of the proteins encoded by ORFs MP, RepA and RepB confirmed the higher similarity between the African clones (97.8-99.3%) than between these and MSV-R (95.1-97.1%). However the amino acid sequences of the protein encoded by ORF CP (capsid protein) were very conserved among all the 4 clones, suggesting a high selection pressure on this ORF.

Base Sequence↗
PubMed1996

Four families with loss of function mutations of the thyrotropin receptor.

We observed four families with loss of function mutations of the TSH receptor gene. One patient had a homozygous Pro162 Ala substitution. The three other were compound heterozygotes: 1) Gln324-->Stop and Asp410 Asn2), Cys41 Ser and Phe525 Leu, 3) Cys390 Trp and Trp546-->Stop. In all patients, the plasma TSH concentration was increased, whereas T3 and T4 concentrations were normal. The TSH levels were normal in the heterozygous parents. These results confirmed the recessive character of TSH receptor defects. Expression of the various mutated receptors in transfected COS-7 cells demonstrated the impairment of their function. We studied the expression of the receptors on the cell surface by immunofluorescence, their ability to bind hormone, and their capacity to activate adenylate cyclase. Some mutations allowed us to identify sites that are especially important for receptor function. The substitution Cys390 Trp abolished high affinity hormone binding. Receptor mutated at Asp410 Asn bound the hormone normally, but failed to activate adenylate cyclase. This result underscores the role of this acidic extracellular residue, close to the first transmembrane segment, in signal transmission. The Phe525 Leu substitution also markedly impaired adenylate cyclase activation, underlining the importance of the second intracellular loop in receptor signaling.

Adenylyl Cyclases↗
PubMed1995

[Cyclophosphamide during pregnancy: a safe prescription].

Cyclophosphamide is an alkylating agent used to treat haematologic malignant diseases and multisystem diseases with progressive glomerulonephritis. It is rarely prescribed during pregnancy. We report a case of Henoch-Schönlein purpura discovered at the end of the first trimester of pregnancy. Despite steroid therapy, glomerulonephritis worsened and 100 mg/day cyclophosphamide per os was administered from 28th week till delivery. The infant, prematurely born, was normal and did not have any haematological disorder. Congenital malformations are often reported (5 out of 19 newborns exposed in utero to cyclophosphamide), but in all those cases, there was another potentially teratogenic agent: either radiotherapy or another antineoplastic drug. Therefore, if mother's life is in jeopardy, cyclophosphamide therapy should be given and not postponed.

Adult↗
PubMed1990

Amino acids and memory consolidation in the cricket. I: Changes in the titer of free amino acids in nervous tissue after learning.

The involvement of certain amino acids in the memory consolidation process was investigated in the cricket Pteronemobius sp. Thirsty crickets were trained to constantly turn to one side of a symmetrical Y-shaped maze using reinforcement with water. Controls were trained to turn to both sides of the maze according to a random program. Animals were sacrificed immediately after training and free amino acid fractions were isolated from whole brain, subesophagic, prothoracic, mesothoracic and metathoracic ganglia homogenates and analyzed by high pressure liquid chromatography. A complex pattern of variation in the titer of amino acids emerged after learning, where the changes differed among the various ganglia. The most conspicuous change was an increase in the levels of urea and an amino acid-like compound related to the urea cycle, in all ganglia except the subesophagic one, if compared to controls. Arginine increased in the subesophagic ganglion, but decreased significantly in the metathoracic ganglion. The variation of ganglionic amino acid levels and its possible relation to mnemonic processes is discussed.

Amino Acids↗
PubMed1990

Amino acids and memory consolidation in the cricket. II: Effect of injected amino acids and opioids on memory.

The effect of injections of selected amino acids on memory, given before a maze-learning, was investigated. Thirsty crickets (Pteronemobius sp.) were trained to turn only to one side of a symmetrical Y-shaped maze using reinforcements with water. The insects retained the learned task 24 hr later. N2 anoxia applied immediately after training produced retrograde amnesia. Injections of Ala, Arg, Gln or morphine prior to training blocked the amnesic action of anoxia, whereas those of Cys, Met, Pro, Orn, octopamine or naloxone did not. Naloxone blocked long-term memory formation, but not learning, whereas Pro and Orn blocked both. The antiamnesic effect of morphine and Arg, but not that of Ala, was blocked by naloxone. A hypothesis assigning a neuromodulatory role to some amino acids is put forward.

Amino Acids↗
PubMed1990

[Partial atrioventricular block and prolonged QT interval in 4 premature infants receiving diphemanil].

Four premature infants presenting with episodes of bradycardia in the first weeks of life were given diphemanil. One of them received an overdose accidentally. Paradoxically, this induced a permanent bradycardia leading to the discovery of a grade II A-V block as well as a prolonged QT interval. Discontinuation of the drug resulted in a prompt normalization of these changes. It is felt that this anticholinergic therapy may have caused a prolongation of the QT interval and, therefore, a partial A-V block in case of sinus tachycardia. Thus, such a therapy should not be given to young premature infants without having checked the QT interval on a ECG tracing and having made sure that it is adapted to the actual heart rate. It is also advised to reduce usual doses.

Bradycardia↗
PubMed1984

[Cardiac failure complicating laryngomalacia in a newborn infant].

A case of cardiac failure with pulmonary hypertension in a neonate with laryngomalacia is described. The interest of clinical and echocardiographical follow up and transcutaneous blood gas measurements to monitor the course of any upper airway obstruction is emphasized.

Airway Obstruction↗
PubMed1983

[Histologic and ultrastructural forms of benign tumors of the kidney with renin secretion. Functional implications].

Two cases of renal benign renin-secreting tumours (juxta-glomerular cells tumors) have been compared by optical and electron microscopy. The first is the simplest type of tumoral form which can be observed. This contains secretory cells similar to epitheloid cells of normal juxta-glomerular apparatus, which multiply in well developed arteriolar and capillary network. As in afferent arterioles of glomeruli, transformation of parietal smooth cells in secretory cells can be observed. This results in the presence of intermediate cells, containing both contractile filaments and secretory granules. This tumor does not contain nerves. The second tumor has a more complex structure. Beside usual secretory cells, tubular formations and adrenergic amyelinic nerves are observed. Tubes and nerves have been described separated in many juxta glomerular cells tumors but had never been observed in association. Tubules with small lumen are made of highly dystrophic cells. High concentration of "kallikrein" in tumoral tissue, strongly suggests that they proceed from distal tubule. Unmyelinated nerves from varicosities containing densely cored vesicles characteristics of adrenergic nerves, and synaptic terminal endings on secretory cells. The presence of nerve bundles suggest a nervous regulation of tumoral secretions. This hypothesis is confirmed by dynamic explorations of sympathetic system.

Adult↗