Landscape features impact connectivity between soil populations: a comparative study of gene flow in earthworms.

Landscape features are known to alter the spatial genetic variation of aboveground organisms. Here, we tested the hypothesis that the genetic structure of belowground organisms also responds to landscape structure. Microsatellite markers were used to carry out a landscape genetic study of two endogeic earthworm species, Allolobophora chlorotica (N = 440, eight microsatellites) and Aporrectodea icterica (N = 519, seven microsatellites), in an agricultural landscape in the North of France, where landscape features were characterized with high accuracy. We found that habitat fragmentation impacted genetic variation of earthworm populations at the local scale. A significant relationship was observed between genetic diversity (He , Ar ) and several landscape features in A. icterica populations and A. chlorotica. Moreover, a strong genetic differentiation between sites was observed in both species, with a low degree of genetic admixture and high Fst values. The landscape connectivity analysis at the regional scale, including isolation by distance, least-cost path and cost-weighted distance approaches, showed that genetic distances were linked to landscape connectivity in A. chlorotica. This indicates that the fragmentation of natural habitats has shaped their dispersal patterns and local effective population sizes. Landscape connectivity analysis confirmed that a priori favourable habitats such as grasslands may constitute dispersal corridors for these species.

Acute stroke in the very elderly: epidemiological features, stroke subtypes, management, and outcome in Martinique, French West Indies.

BACKGROUND AND PURPOSE: Stroke incidence increases with increasing age and has an impact on daily living in many areas. With increasing life expectancy, old people will constitute the majority of stroke victims. We present the first stroke study focusing on very old patients in a black Caribbean population (Martinique, French West Indies). METHODS: All Martinican patients suffering from their first-ever stroke during 1 calendar year between June 1, 1998, and May 31, 1999, were included. Epidemiological, clinical, neuroimaging, management, and outcome data during the first month were collected and compared between very old patients (>or=85 years) and patients aged <85 years. RESULTS: One hundred patients aged >or=85 years and 480 patients aged <85 years were included (sex ratio, women/men, 2.84 and 0.85, respectively; mean+/-SD age, 88.8+/-3.6 and 65.8+/-13.3 years, respectively). The incidence of first-ever stroke was 1.64/1000 per year in the Martinique population and 18.2/1000 per year in patients aged >or=85 years. Elderly patients showed a significantly lower proportion of diabetes (19.1% versus 32.2%; P=0.012) and smoking (0% versus 8.4%; P=0.004) and a higher proportion of peripheral artery disease (23.4% versus 11.4%; P=0.002). Prevalence of hypertension was identical in the 2 groups (70%). There were no significant differences in stroke types or ischemic stroke subtypes between the 2 groups. Active medical care was poorer in older than in younger patients (hospitalization rate, 89% versus 94.4%; admission to neurological ward, 8% versus 23.8%; rate of performance of a CT scan, 82% versus 94%). The 30-day case fatality rate was approximately twice as high in elderly patients (31% versus 16.7%; P=0.0009), and disability (Rankin Scale score >or=3) in survivors was markedly higher (78% versus 48%; P<0.0001). CONCLUSIONS: In Martinique, the incidence of first-ever stroke in very old black Caribbean patients seems similar to that in white patients. They have the same pathological type and subtype of stroke as do young patients. The poorer stroke outcome found in the elderly during the first month may be related in large part to less active management than in younger patients.

ERMANCIA: Epidemiology of Stroke in Martinique, French West Indies: Part I: methodology, incidence, and 30-day case fatality rate.

BACKGROUND AND PURPOSE: The ERMANCIA (Etude Réalisée en Martinique et Centrée sur l'Incidence de Accidents vasculaires cérébraux) study was designed to provide the first comparable epidemiological data on stroke in a black Caribbean population. METHODS: ERMANCIA was a prospective community-based study performed in Martinique (French West Indies) from June 1, 1998, to May 31, 1999. The black at-risk population was approximately 360 000. Multiple sources were used to identify hospitalized and nonhospitalized patients with first-ever stroke. RESULTS: Five hundred eighty patients (285 men and 295 women; mean+/-SD age, 71.2+/-14 years) suffered from a first-ever in a lifetime stroke, yielding a crude annual incidence of 164/100 000 per year (95% CI, 151 to 177). The rates adjusted by age and sex to the French population (1999 census) and to the European population were 202 (95% CI, 185 to 218) and 151 (95% CI, 139 to 164), respectively. Thirty-eight patients (6.5%) were not hospitalized during the acute phase of the stroke; 92.8% had CT scan. Pathological types of strokes were infarction (79.8%, including 23% of lacunar strokes), intracerebral hemorrhage (14.3%), subarachnoid hemorrhage (3.4%), and undetermined (2.4%). The main risk factors for stroke were hypertension (69.1%) and diabetes (29.5%). The 30-day case fatality rate was 19.3% (15.8% for cerebral infarction and 37.3% for intracerebral hemorrhage). CONCLUSIONS: In Martinique, the ERMANCIA population-based study showed a high stroke incidence and a high prevalence of hypertension and diabetes in the stroke population compared with those observed in continental France. Epidemiological data on stroke in African Caribbeans from Martinique are comparable to those reported in blacks from the United States and United Kingdom.

[Rehabilitation treatment in lumbar canal stenosis. Intermediate results of a prospective study (Télemar)]. / Prise en charge rééducative des sténoses du canal lombaire. Résultats intermédiaires d'une étude prospective (Télemar).

STUDY DESIGN: Lumbar spine stenosis is a common cause of lower back pain and lower extremity pain especially in people over 60-years-old. Treatment can be surgical or non-surgical. The efficacy of these treatments remains unclear. The purpose of this study was to assess the result of a medical management in a prospective study. Preliminary results are presented. PATIENTS AND METHODS: Patients following the clinical and the radiological criteria of inclusion were included in the study. Pain was assessed by visual analogic scale (VAS) and Oswestry scale. Sixty patients meeting inclusion criteria underwent non-surgical intervention including therapeutic exercises and 2 epidural injections. Patients were followed up at 3 and 6 months. RESULTS: The main score on VAS was 5.2 for lumbar pain, 5.8 for radicular pain and 21/50 on the Oswestry scale. Three months later an improvement was noticed in 12 cases. Thirty-seven patients remained unchanged and surgery was decided for 11 patients. At 6 months an improvement was reported by 47% of the patients who have been managed by conservative treatment. No predictive factor except VAS was noticed. DISCUSSION: Our results are inferior to those previously reported. Most of previous studies are retrospective and criteria of assessment are not based on functional scale as we done. The fact that the treatment management was ambulatory without supervision is probably the main explanation. CONCLUSION: Conservative treatment for spinal lumbar stenosis remains a reasonable option.

Intramedullary neurenteric cyst without any associated malformation. One case evaluated by RMI and electron microscopic study.

A 46 years old woman presented with several years history of low back pain. For five years she suffered from weakness of the left lower limb and three years later she experienced an episode of right foot weakness. She suffered too from occasional urinary urgency. The examination showed decreased power and diminished sensory perception in the left leg. On myelography, a block at L2 level was observed. RMI evaluation showed an intramedullary cyst in the anterior part of the spinal cord without any enhancement of its wall by the Gadolinium. At operation a thin-wall cyst was found containing clear fluid. After a biopsy of the wall, a cystosubarachnoid shunt was performed. Histological examination of the surgical sample showed a simple cuboidal epithelium lying on collagen fibrills. Electron microscopic studies showed ciliated cells with a clearly-visible basement membrane. The diagnosis of neurenteric cyst was confirmed. In the postoperative course the patient complained about sensory loss of the legs and the perineal area. Six months later, she exhibited a sensory disturbance of the feet and the right sacral area, a motor deficit of the distal left leg without urinary disturbance. Neurenteric cysts are dysraphic lesions which can be observed without other abnormalities. They are usually extramedullary and the intramedullary forms are very rare: among 5 cases reported in the literature, one has been evaluated by RMI. In the absence of enhancement by the Gadolinium, the other possible diagnosis seems an ependymal cyst. Contrary to extramedullary forms the postoperative course of intramedullary neurenteric cysts are not always eventful. Because the cyst wall cannot be removed, repeated RMI are desirable in the follow-up.