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1.
Trials ; 22(1): 208, 2021 Mar 12.
Article in English | MEDLINE | ID: mdl-33712076

ABSTRACT

BACKGROUND: Arterial hypotension induced by general anesthesia is commonly identified as a risk factor of morbidity, especially neurological, after cardiac or noncardiac surgery in adults and children. Intraoperative hypotension is observed with sevoflurane anesthesia in children, in particular in neonates, infants younger than 6 months, and preterm babies. Ephedrine is commonly used to treat intraoperative hypotension. It is an attractive therapeutic, due to its dual action on receptors alpha and beta and its possible peripheral intravenous infusion. There are few data in the literature on the use of ephedrine in the context of pediatric anesthesia. The actual recommended dose of ephedrine (0.1 to 0.2 mg/Kg) frequently leads to a therapeutic failure in neonates and infants up to 6 months of age. The use of higher doses would probably lead to a better correction of hypotension in this population. The objective of our project is to determine the optimal dose of ephedrine for the treatment of hypotension after induction of general anesthesia with sevoflurane, in neonates and infants up to 6 months of age. METHODS: The ephedrine study is a prospective, randomized, open-label, controlled, dose-escalation trial. The dose escalation consists of 6 successive cohorts of 20 subjects. The doses studied are 0.6, 0.8, 1, 1.2, and 1.4 mg/kg. The dose chosen as the reference is 0.1 mg/kg, the actual recommended dose. Neonates and infants younger than 6 months, males and females, including preterm babies who undergo a surgery with general anesthesia inducted with sevoflurane were eligible. Parents of the subject were informed. Then, the subjects were randomized if presenting a decrease in mean blood pressure superior to 20% of their initial mean blood pressure (before induction of anesthesia), despite a vascular filling with sodium chloride 0.9%. The primary outcome is the success of the therapy defined as an mBP superior to 80% of the baseline mBP (prior to anesthesia) within 10 min post ephedrine administration. The subjects were followed-up for 3 days postanesthesia. DISCUSSION: This study is the first randomized, controlled trial intending to determine the optimal dose of ephedrine to treat hypotension in neonates and infants below 6 months old. TRIAL REGISTRATION: ClinicalTrials.gov NCT02384876 . Registered on March 2015.


Subject(s)
Ephedrine , Hypotension , Adult , Anesthesia, General/adverse effects , Blood Pressure , Child , Ephedrine/adverse effects , Female , Humans , Hypotension/chemically induced , Hypotension/diagnosis , Hypotension/drug therapy , Infant , Infant, Newborn , Male , Prospective Studies , Randomized Controlled Trials as Topic , Vasoconstrictor Agents/adverse effects
2.
Virology ; 546: 98-108, 2020 07.
Article in English | MEDLINE | ID: mdl-32452421

ABSTRACT

Two members of the genus Capulavirus (Geminiviridae) are transmitted by aphids including Alfalfa leaf curl virus (ALCV) transmitted by Aphis craccivora. The capulavirus Euphorbia caput-medusae latent virus was shown here to be transmitted also by A. craccivora, using the population EuphorbiaSA. ALCV was transmissible by several A. craccivora populations including Robinia, but not the EuphorbiaSA population, reflecting a high transmission specificity. Typical of the circulative-persistent mode of transmission, ALCV persists through insect molts. ALCV accumulation and localization were analyzed in whole insects, midguts, hemolymphs, and heads of aphids from vector and non-vector populations of A. craccivora and from the non-vector species Acyrthosiphon pisum. Vector and non-vector populations could be distinguished by contrasted virus accumulations and midgut intracellular localization consistent with a gut barrier to the transmission of ALCV in A. pisum and a primary salivary gland barrier in A. craccivora.


Subject(s)
Aphids/virology , Geminiviridae/physiology , Insect Vectors/virology , Medicago sativa/virology , Plant Diseases/virology , Animals , Aphids/physiology , Geminiviridae/classification , Geminiviridae/genetics , Geminiviridae/isolation & purification , Insect Vectors/physiology , Phylogeny , Species Specificity
3.
Rev Mal Respir ; 36(8): 971-984, 2019 Oct.
Article in French | MEDLINE | ID: mdl-31521432

ABSTRACT

As a result of the constantly increasing epidemic of obesity, it has become a common problem in the intensive care unit. Morbid obesity has numerous consequences for the respiratory system. It affects both respiratory mechanics and pulmonary gas exchange, and dramatically impacts on the patient's management and outcome. With the potential for causing devastating respiratory complications, the particular anatomical and physiological characteristics of the respiratory system of the morbidly obese subject should be carefully taken into consideration. The present article reviews the management of obese patients in respiratory failure, from noninvasive ventilation to tracheostomy, including postural and technical issues, and explains the physiologically based ventilatory strategy both for NIV and invasive mechanical ventilation up to the weaning from the ventilatory support.


Subject(s)
Obesity Hypoventilation Syndrome/therapy , Obesity/complications , Respiration, Artificial , Respiratory Distress Syndrome/therapy , Catheterization , Critical Care , Humans , Intubation, Intratracheal , Patient Positioning , Respiratory Distress Syndrome/etiology , Tracheostomy
4.
Diagn Interv Imaging ; 99(10): 625-632, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29754870

ABSTRACT

PURPOSE: To evaluate operator and patient irradiation during radiofrequency ablation (RFA) of common atrial flutter (AF) using three different fluoroscopy settings. MATERIAL AND METHOD: A total of 38 patients who underwent RFA of AF with three different fluoroscopy settings (low dose, standard dose and collimated field) were included. Twelve patients (11 men, 1 woman; mean age, 67±12 [SD]years) were included in the low dose group (3.75 frames per second), 13 patients (13 men; mean age, 66±8 [SD]years) were included in the standard dose group (7.5 frames per second) and 13 patients (13 men; mean age, 71±12 [SD]years) were included in the collimated field group (7.5 frames per second). Operator and patient exposure were compared between groups. RESULT: No differences in procedure time and radiation exposure were found between the three groups. In the low dose group, mean operator X-ray exposures of eye-lens (4.7±2.9 [SD]µSv/h; range: 0.9-10.5µSv/h), whole body (1.6±1.2 [SD]µSv/h; range 0.5-3.6µSv/h) and hand skin (11.1±10.8 [SD] µSv/h; range 2.4-35.4µSv/h) were significantly lower than those in the standard dose group (P<0.001). Significant patient dose reduction was found between low dose group (0.7±0.4 [SD]Gy/h; range: 0.3-0.9Gy/h) and standard (1.7±0.5 [SD]Gy/h; range: 0.8 to 3.9Gy/h) and collimated (1.8±0.5 [SD]Gy/h; range: 0.7-3.0Gy/h) groups (P<0.01). CONCLUSION: The use of a low dose setting (3.75 f/s) during fluoroscopy dramatically reduces operator's irradiation during RFA of AF by a mean of 90%.


Subject(s)
Fluoroscopy/methods , Occupational Exposure/prevention & control , Radiation Dosage , Radiation Exposure/prevention & control , Radiofrequency Ablation , Aged , Aged, 80 and over , Atrial Flutter/surgery , Female , Humans , Male , Middle Aged , Occupational Exposure/statistics & numerical data , Radiation Exposure/statistics & numerical data , Radiation Protection , Retrospective Studies
5.
Virus Res ; 243: 44-51, 2018 01 02.
Article in English | MEDLINE | ID: mdl-28988981

ABSTRACT

TYLCV-IS76 is an unusual recombinant between the highly recombinogenic tomato yellow leaf curl virus (TYLCV) and tomato yellow leaf curl Sardinia virus (TYLCSV), two Mediterranean begomoviruses (Geminiviridae). In contrast with the previously reported TYLCV/TYLCSV recombinants, it has a TYLCSV derived fragment of only 76 nucleotides, and has replaced its parental viruses in natural conditions (Morocco, Souss region). The viral population shift coincided with the deployment of the popular Ty-1 resistant tomato cultivars, and according to experimental studies, has been driven by a strong positive selection in such resistant plants. However, although Ty-1 cultivars were extensively used in Mediterranean countries, TYLCV-IS76 was not reported outside Morocco. This, in combination with its unusual recombination pattern suggests that it was generated through a rare and possibly multistep process. The potential generation of a recombination breakpoint (RB) at locus 76 (RB76) was investigated over time in 10 Ty-1 resistant and 10 nearly isogenic susceptible tomato plants co-inoculated with TYLCV and TYLCSV clones. RB76 could not be detected in the recombinant progeny using the standard PCR/sequencing approach that was previously designed to monitor the emergence of TYLCV-IS76 in Morocco. Using a more sensitive PCR test, RB76 was detected in one resistant and five susceptible plants. The results are consistent with a very low intra-plant frequency of RB76 bearing recombinants throughout the test and support the hypothesis of a rare emergence of TYLCV-IS76. More generally, RBs were more scattered in resistant than in susceptible plants and an unusual RB at position 141 (RB141) was positively selected in the resistant cultivar; interestingly, RB141 bearing recombinants were detected in resistant tomato plants from the field. Scenarios of TYLCV-IS76 pre-emergence are proposed.


Subject(s)
Begomovirus/isolation & purification , Plant Diseases/virology , Recombination, Genetic , Solanum lycopersicum/virology , Animals , Begomovirus/classification , Begomovirus/physiology , Morocco , Plant Leaves/virology
6.
Arch Pediatr ; 23(9): 913-20, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27388909

ABSTRACT

OBJECTIVE: Skin-to-skin contact shows benefits in the relationship developed between a mother and her premature infant. In the skin-to-skin session, face-to-face exchanges are impossible in vertical infant positioning. We therefore undertook an observational, prospective, single-center study using kangaroo "supported diagonal flexion" (SDF) positioning. The first aim was to evaluate the safety of kangaroo SDF positioning compared to the usual vertical positioning. The second aim was to evaluate SDF positioning on early communication between the mother and her infant and to improve their well-being. PARTICIPANTS AND SETTING: Fifteen mothers and their very premature infants (birth 26<32 weeks' gestation) were assigned to one of the two kangaroo positioning modes, either the current vertical positioning (n=7) or SDF positioning (n=8). DESIGN: Physiological variables and critical events were recorded before, during, and after ten successive skin-to-skin contact sessions. The first and last sessions were videotaped to allow later behavioral measurements. Mothers' risk for depression and feelings about the way they experienced communication with their infant were assessed through questionnaires. RESULTS: In terms of the infant's physiology, no negative effects were associated with SDF positioning in comparison with the usual vertical positioning. SDF positioning led to fewer disorganized gestures, negative vocalizations, and drowsiness, in favor of more deep sleep. SDF led to more mother-infant eye-to-eye contact as well as maternal vocalizations, smiles, and caressing, although these differences did not reach significance. The score for the risk of postnatal depression decreased significantly between the first and the last session in the SDF group, whereas it did not change in the vertical positioning group. CONCLUSION: These results support the idea that the kangaroo SDF positioning technique is physiologically safe, has obvious immediate benefits on mothers' infant-directed communicative behaviors, and respects the baby's naturally flexed and asymmetrical tonic neck posture. It is an innovative, inexpensive, easy-to-use technique in daily practice, by all healthcare professionals working in a neonatal intensive care unit. These data suggest that the current kangaroo positioning technique could be improved. More studies are needed to confirm the benefits and safety of the kangaroo SDF positioning in larger groups of preterm infants.


Subject(s)
Communication , Infant, Premature , Kangaroo-Mother Care Method/methods , Mother-Child Relations , Adult , Depression, Postpartum/prevention & control , Female , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Prospective Studies , Young Adult
7.
Virology ; 486: 291-306, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26519598

ABSTRACT

Recombinant viruses are increasingly being reported but the dynamics of their emergence is rarely documented. A new recombinant Tomato yellow leaf curl virus (TYLCV-IS76) was detected for the first time in 2010 in Southern Morocco (Souss). An original diagnostic tool was needed to fit its unusual recombination profile. Although IS76 was detected following the appearance of Tylc symptoms on tolerant tomato plants, symptoms could not be associated to IS76 or to a synergy with criniviruses. According to infection profiles of Tylc-associated viruses determined on 879 plant samples collected between 1998 and 2014 and a Bayesian inference applied to genomic sequences of representatives of TYLCV, IS76 emerged in Southern Morocco at the end of the 1990s, replaced the parental viruses between 2004 and 2012 in Souss and is spreading towards the North of Morocco. The emergence of IS76 coincides with the increasing use of tolerant cultivars in the 2000s.


Subject(s)
Begomovirus/genetics , Plant Diseases/virology , Recombination, Genetic , Satellite Viruses/genetics , Solanum lycopersicum/virology , Base Sequence , Bayes Theorem , Begomovirus/classification , Begomovirus/isolation & purification , Molecular Sequence Data , Phylogeny , Plant Leaves/virology , Satellite Viruses/classification , Satellite Viruses/isolation & purification , Viral Proteins/genetics
9.
Article in English | MEDLINE | ID: mdl-23367383

ABSTRACT

The analysis of high-density activation maps of atrial fibrillation (AF) provides fundamental insights into the fibrillation wave propagation patterns and thus the mechanisms of AF. Current annotation of local activations in unipolar atrial electrograms and the construction of fibrillation waves require labor-intensive manual editing. To enhance the possibilities for spatiotemporal analysis of AF, we developed a rapid and fully automated procedure to accurately identify local, intrinsic atrial deflections and construct fibrillation waves based on these deflections. In this study, the automated procedure was validated using manually annotated electrograms and wave maps. We show that the novel procedure accurately detects intrinsic deflections (sensitivity=87%, positive predictive value=89%) and that reconstructed wave maps correlate well with manually edited wave maps in terms of number of waves (r=0.96), intra-wave conduction velocity (r=0.97), AF cycle length (r=0.97), and wave size (r=0.96) (p<0.01 in all cases). The automated procedure is therefore an adequate substitute for manual annotation.


Subject(s)
Atrial Fibrillation/physiopathology , Automation , Probability , Algorithms , Humans , Signal-To-Noise Ratio
10.
Arch Pediatr ; 18(3): 313-23, 2011 Mar.
Article in French | MEDLINE | ID: mdl-21288702

ABSTRACT

The quality of nutritional support impacts not only the growth and quality of growth of preterm infants, but also all aspects of their development. In order to provide optimal nutrition, two main rules should be followed: optimise early parenteral nutrition and introduce appropriate enteral nutrition preferably with the mother's milk as early as possible. Recommendations have recently increased early energy and protein intake. The term "aggressive nutrition" has been introduced to qualify these changes, but we prefer the term "optimal nutrition," which more precisely reflects the physiology and needs of the preterm infant. Specific efforts should be continued to improve physician training in neonatal nutrition and to facilitate the dissemination of the most recent recommendations. Standardization of nutritional protocols in neonatal units should be promoted as a way to improve overall nutritional care. A full field of research remains open to determine the most effective nutritional strategy for preterm infants in order to maximize their growth and development.


Subject(s)
Infant Nutritional Physiological Phenomena , Infant, Premature , Brain/growth & development , Breast Feeding , Enterocolitis, Necrotizing/prevention & control , Gastroesophageal Reflux/prevention & control , Humans , Infant, Newborn , Lung/growth & development , Nutritional Support
11.
Environ Entomol ; 40(5): 989-98, 2011 Oct.
Article in English | MEDLINE | ID: mdl-22251711

ABSTRACT

Bemisia tabaci populations belonging to Middle East-Asia Minor one (MEAM1) and Mediterranean (MED) groups (formerly biotype B and Q, respectively) have spread throughout the world. Although the introduction of MEAM1 is documented from several Caribbean islands, it is generally not known whether MED has also been introduced; whether indigenous populations have survived; and if in the affirmative, to which group(s) they belonged. Whiteflies were collected from seven islands on various plant species. The prevalence of MEAM1 and non-MEAM1 individuals was assessed using a microsatellite approach validated with sequences of the mitochondrial cytochrome oxidase I (mtCOI) gene. Of the 262 samples tested, 247 exhibited the MEAM1 pattern, whereas none showed the MED pattern. The mtCOI gene was partially sequenced from a sample of individuals exhibiting MEAM1 (n = 15) and non-MEAM1 patterns (n = 8) and compared with type sequences. The 15 individuals exhibiting the MEAM1 pattern were confirmed to belong to MEAM1. Of the eight individuals representative of the six non-MEAM1 patterns, two belonged to the indigenous New World (NW) group of B. tabaci (NW), one belonged to a distinct species of Bemisia, and five belonged to MEAM1. One individual belonging to NW exhibited 99.9% nucleotide identity with a NW individual from Puerto Rico. The other was identified as the most divergent individual of the North and Central American genetic cluster. We conclude that a highly homogenous MEAM1 population has extensively settled in the Caribbean and that heterogeneous NW populations were still detectable although severely displaced.


Subject(s)
Hemiptera , Introduced Species , Animals , Caribbean Region , Electron Transport Complex IV/genetics , Hemiptera/genetics , Microsatellite Repeats , Sequence Analysis, DNA
12.
Ann Fr Anesth Reanim ; 29(10): 687-92, 2010 Oct.
Article in French | MEDLINE | ID: mdl-20729034

ABSTRACT

OBJECTIVE: The purpose of the present study was to compare how many inflate and deflate are necessary to maintain the endotracheal tube cuff pressure between 15 and 35 cm H2O by using air, O2-N2O mix or saline solution. STUDY DESIGN: Randomized and prospective study. PATIENTS AND METHODS: Ninety children from 1 month to 15 years of age were included in the study. All patients were ventilated with O250%-N2O50%. Subsequently, the patients were divided in three groups: (1) Group 1: patients with air inflated cuffs; (2) Group 2: patients with O2-N2O mix inflated cuffs; (3) Group 3: patients with saline solution inflated cuffs. In all groups cuffs were inflated to reach an intracuff pressure of 20 cm H2O. The cuff pressure was then monitored every 10 minutes and adjusted to be between 15 and 35 cm H2O. Laryngeal and tracheal symptoms were noted in the recovery room. RESULTS: The three groups of patients were similar for age, weight, and sex. The length of surgery was significantly longer in Group 3. The deflate rate was higher in Group 1 (60%) than in Group 2 (10%) or 3 (3.3%) (p<0.0001). The inflate rate was higher in Group 2 (76.6%) than in Group 1 or 3 (both 3.3%) (p<0.0001). Side effects were comparable in the three groups of patients. CONCLUSION: Using air or O2-N2O mix to inflate cuffs is not reliable. SSI helps to maintain a more stable cuff pressure but monitoring is difficult and sometimes contraindicated by tracheal tubes producers. Inflating cuffs with air and regularly monitoring pressure is the most reliable and easiest technique.


Subject(s)
Air , Intubation, Intratracheal/methods , Nitrous Oxide/administration & dosage , Oxygen/administration & dosage , Sodium Chloride/administration & dosage , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Male , Prospective Studies
14.
Rev Chir Orthop Reparatrice Appar Mot ; 94(5): 490-7, 2008 Sep.
Article in French | MEDLINE | ID: mdl-18774024

ABSTRACT

PURPOSE OF THE STUDY: The purpose of this study is to assess the consequences brought by selective dorsal arthrodesis of thoracic spine (T1-T6) to the growth of spine and thoracic volume in operated and sham-operated New Zealand White rabbits, between prepubertal age and the end of somatic growth, through the study of computerised tomography (CT) scans periodically carried out on them after arthrodesis surgery. MATERIAL AND METHODS: Nine female rabbits were subjected to surgery for selective dorsal arthrodesis of the upper thoracic spine and three were sham-operated. Surgery was performed at age nine weeks, before the onset of puberty. Two "C"-shaped titanium bars were placed beside the spinous processes of the thoracic vertebrae to obtain a selective posterior arthrodesis of the first six thoracic vertebrae. Under general anesthesia, three CT scans were performed, 10 (t1), 55 (t2) and 139 (t3) days after surgery. Measures were obtained by Myrian Pro software for three different groups: group 1 with complete fusion, group 2 with incomplete fusion, group 3 sham-operated. RESULTS: The total dorsal and ventral lengths of thoracic vertebral bodies in the spinal segment T1-T6 was smaller in group 1 and group 2 than in group 3, whereas no differences were observed between the three groups in the T7-T12 segment. The average of the dorsoventral/laterolateral thoracic diameter ratio at fused levels was less than 1 in group 1 as well as in group 2; on the contrary, in group 3 it was greater than 1. The sternum and lung volume grow less. CONCLUSIONS: Vertebral arthrodesis in the treatment of progressive idiopathic scoliosis in prepubertal patients is not ideal, but is still a choice in treating major deformities of the spine. Postoperative assessment of spinal deformity is essential, feasible and recordable through CT scans. Dorsal arthrodesis in prepubertal rabbits changes thoracic growth patterns. In operated rabbits, the dorsoventral thoracic diameter grows more slowly than the laterolateral thoracic diameter. The sternum, the total lengths of thoracic vertebral bodies in the spinal segment T1-T6 and lungs grow less. The Crankshaft phenomenon is evident at the fused vertebral levels where there is a reduction of thoracic kyphosis.


Subject(s)
Spinal Fusion/methods , Spine/growth & development , Thoracic Vertebrae , Thorax/growth & development , Animal Experimentation , Animals , Data Interpretation, Statistical , Female , Rabbits , Sexual Maturation , Thoracic Vertebrae/growth & development , Tomography, X-Ray Computed
15.
Heredity (Edinb) ; 100(3): 316-25, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18073781

ABSTRACT

The geographic range of plant pests can be modified by the use of glasshouses. Bemisia tabaci, originating from warm to hot climates, has been shown to be a complex of distinct genetic groups with very limited gene flow. The genetic structure of this pest was studied in glasshouses in southern France, a region beyond the northern limit of its open-field development area in Europe. Seven microsatellite loci were scored in 22 populations sampled from various regions over 3 years. Two genetic groups were distinguished using a Bayesian clustering method and were assigned to the so-called biotypes B and Q using the gene sequence of cytochrome oxidase 1 (CO1). All but one population corresponded to biotype Q, even though only biotype B was previously reported. Despite the enclosed environment of glasshouses and their expected isolation due to low outdoor survival during the winter, only limited differentiation among biotype Q glasshouses was observed. A single sample site was notable for a decrease in expected heterozygosity and the mean number of alleles over the years. The lack of spatial genetic structure among biotype Q populations was indicative of a recent colonization event combined with large dispersal at all spatial scales. This migration pattern of biotype Q populations was further supported by additional CO1 sequences, since individuals from France, Asia and America exhibited 100% nucleotide identity. The evolution of genetic diversity observed in glasshouses in France is part of the worldwide invasion of biotype Q, which is discussed in light of human activities.


Subject(s)
Evolution, Molecular , Genetic Variation , Genetics, Population , Hemiptera/genetics , Phylogeny , Animals , Base Sequence , Bayes Theorem , Cluster Analysis , Demography , Electron Transport Complex IV/genetics , France , Gene Flow/genetics , Genetic Drift , Genotype , Haplotypes/genetics , Hemiptera/classification , Microsatellite Repeats/genetics , Molecular Sequence Data , Mutation/genetics , Sequence Analysis, DNA
17.
Rev Stomatol Chir Maxillofac ; 107(4): 253-63, 2006 Sep.
Article in French | MEDLINE | ID: mdl-17003760

ABSTRACT

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.


Subject(s)
Hearing Disorders/etiology , Petrous Bone/injuries , Postural Balance/physiology , Sensation Disorders/etiology , Skull Fractures/complications , Adult , Ear, Inner/injuries , Fistula/etiology , Follow-Up Studies , Hearing Loss, Mixed Conductive-Sensorineural/etiology , Humans , Male , Perilymph , Tinnitus/etiology , Unconsciousness/etiology , Vestibular Diseases/etiology
18.
Genet Res ; 87(2): 109-24, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16709274

ABSTRACT

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.


Subject(s)
Chromosome Mapping , Gene Frequency , Hemiptera/genetics , Microsatellite Repeats , Animals , Ecosystem , Genetic Variation , Genome, Insect , Genotype , Geography , Hemiptera/classification , Host-Parasite Interactions/genetics , Phylogeny , Reunion , Seasons
19.
Bull Entomol Res ; 95(1): 29-35, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15705212

ABSTRACT

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.


Subject(s)
Hemiptera/genetics , Animals , DNA, Mitochondrial , Hemiptera/classification , Host-Parasite Interactions , Indian Ocean Islands , Phylogeny , Plant Diseases/parasitology , Plant Diseases/virology , Plants/parasitology
20.
Plant Dis ; 86(12): 1404, 2002 Dec.
Article in English | MEDLINE | ID: mdl-30818457

ABSTRACT

In April 2001, reduced leaf size, leaf curling, yellowing symptoms, and reduced yield were observed in tomato plants in the southwestern (Toliary, Morondava, Miandrivazo) and northern (Antsiranana) regions of Madagascar. Symptoms were similar to those caused by Tomato yellow leaf curl virus (TYLCV, genus Begomovirus, family Geminiviridae). Large populations of Bemisia tabaci (Gennadius) were observed colonizing tomato, other crops, and weeds. Leaf samples were collected from tomato plants from 14 sites located in northern, central, and southern Madagascar. Two plant samples collected near Antsiranana, one sample near Morondava, and one sample near Toliary were positive in triple-antibody sandwich enzyme-linked immunosorbent assay using a begomovirus-specific antibody purchased from ADGEN (Nellies Gates, Auchincruive, Scotland, UK). A 500-bp product was amplified and cloned (2) from two leaf samples collected near Toliary and one near Morondava using a pair of degenerate primers that are expected to amplify a region of the A component of begomoviruses between the intergenic conserved nonanucleotide sequence and the first 200 nucleotides of the coat protein ORF. The sequences corresponding to the two Toliary samples (GenBank Accession Nos. AJ422123 and AJ422124) and the Morondava sample (GenBank No. AJ422125) showed the most significant alignments (NCBI, BLAST) with begomoviruses, Tobacco leaf curl virus from Zimbabwe (GenBank Accession No. AF 350330) and Tomato leaf curl virus from Tanzania (GenBank Accession No. U73498) with 76 to 77% nucleotide identity (Clustal method, MegAlign, DNASTAR, London) and South African cassava mosaic viruses (SACMV GenBank Accession Nos. AJ422132 and AF155806) and East African cassava mosaic viruses from Malawi (GenBank Accession Nos. AJ006459 and AJ006460) with 74 to 75.5% nucleotide identity. The low nucleotide identity suggests that the begomovirus isolated from tomato in Madagascar is a new species. Since the core region of the coat protein gene is a molecular marker for provisional classification of begomoviruses (1), this region was amplified for the Morondava isolate with degenerate primers. The 519nt core fragment obtained showed the most significant alignments with SACMV (GenBank Accession No. AF329227), Cassava geminivirus from Mozambique (GenBank Accession No. AF329240), and with TYLCV (GenBank Accession Nos. AB014346 and AF105975) with 81 to 82% nucleotide identity. According to the current taxonomic criteria (4), the begomovirus from Madagascar is a new one that is related to begomoviruses from the southern part of Africa and to TYLCV and is provisionally named Tomato yellow leaf curl Morondava virus (TYLCMV). Tomato yellow leaf curl disease was previously described in Madagascar by Reckhaus (3) who presumed that it was caused by TYLCV. Although symptoms in the tomato plant from which TYLCMV was isolated were similar to those induced by TYLCV, TYLCV was not detected in our samples. References: (1) J. K. Brown et al. Arch. Virol. 146:1581, 2001 (2) M. Peterschmitt et al. Plant Dis. 83:303, 1999. (3) P. Reckhaus, Maladies et ravageurs des cultures maraîchères: A l'exemple de Madagascar. GTZ, Weikersem, 1997. (4) M. H. V. van Regenmortel et al. Virus Taxonomy. Seventh Rep. Int. Comm. Taxon. Viruses. Academic Press, San Diego, 2000.

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