Musculotopic organization of the motor neurons supplying the mouse hindlimb muscles: a quantitative study using Fluoro-Gold retrograde tracing

We have mapped the motor neurons (MNs) supplying the major hindlimb muscles of transgenic (C57/BL6J-ChAT-EGFP) and wild-type (C57/BL6J) mice. The fluorescent retrograde tracer Fluoro-Gold was injected into 19 hindlimb muscles. Consecutive transverse spinal cord sections were harvested, the MNs counted, and the MN columns reconstructed in 3D. Three longitudinal MN columns were identified. The dorsolateral column extends from L4 to L6 and consists of MNs innervating the crural muscles and the foot. The ventrolateral column extends from L1 to L6 and accommodates MNs supplying the iliopsoas, gluteal, and quadriceps femoris muscles. The middle part of the ventral horn hosts the central MN column, which extends between L2–L6 and consists of MNs for the thigh adductor, hamstring, and quadratus femoris muscles. Within these longitudinal columns, the arrangement of the different MN groups reflects their somatotopic organization. MNs innervating muscles developing from the dorsal (e.g., quadriceps) and ventral muscle mass (e.g., hamstring) are situated in the lateral and medial part of the ventral gray, respectively.MN pools belonging to proximal muscles (e.g., quadratus femoris and iliopsoas) are situatedventral to those supplying more distal ones (e.g., plantar muscles). Finally, MNs innervatingflexors (e.g., posterior crural muscles) are more medial than those belonging to extensors ofthe same joint (e.g., anterior crural muscles). These data extend and modify the MN maps in the recently published atlas of the mouse spinal cord and may help when assessing neuronal loss associated with MN diseases

Long telomeres are associated with clonality in wild populations of the fissiparous starfish Coscinasterias tenuispina

7 páginas, 4 figuras, 3 tablasTelomeres usually shorten during an organism’s lifespan and have thus been used as an aging and health marker. When telomeres become sufficiently short, senescence is induced. The most common method of restoring telomere length is via telomerase reverse transcriptase activity, highly expressed during embryogenesis. However, although asexual reproduction from adult tissues has an important role in the life cycles of certain species, its effect on the aging and fitness of wild populations, as well as its implications for the long-term survival of populations with limited genetic variation, is largely unknown. Here we compare relative telomere length of 58 individuals from four populations of the asexually reproducing starfish Coscinasterias tenuispina. Additionally, 12 individuals were used to compare telomere lengths in regenerating and non-regenerating arms, in two different tissues (tube feet and pyloric cecum). The level of clonality was assessed by genotyping the populations based on 12 specific microsatellite loci and relative telomere length was measured via quantitative PCR. The results revealed significantly longer telomeres in Mediterranean populations than Atlantic ones as demonstrated by the Kruskal–Wallis test (K=24.17, significant value: P-valueo0.001), with the former also characterized by higher levels of clonality derived from asexual reproduction. Telomeres were furthermore significantly longer in regenerating arms than in non-regenerating arms within individuals (pyloric cecum tissue: Mann–Whitney test, V=299, P-valueo10− 6; and tube feet tissue Student's t= 2.28, P-value =0.029). Our study suggests that one of the mechanisms responsible for the long-term somatic maintenance and persistence of clonal populations is telomere elongation.This research was financially supported by a PhD fellowship FPI-MICINN (BES-2011-044154) (ACG), the European ASSEMBLY project (227799), the Swedish Royal Academy of Sciences (ACG) and the Spanish Government project CTM2010-22218-C02. The research was also supported by a ‘Juan de la Cierva’ contract from the Spanish Government (RPP) and by the Adlerbertska Research Foundation (HNS).Peer reviewe

Immediate versus deferred treatment for advanced prostatic cancer: Initial results of the Medical Research Council trial

Objective To compare the effect on the course of advanced prostate cancer of hormone treatment commenced on diagnosis with that deferred until clinically significant progression occurs. Patients and methods Nine hundred and thirty-eight patients with locally advanced or asymptomatic metastatic prostate cancer were randomized either to immediate treatment (orchidectomy or luteinizing hormone-releasing hormone analogue) or to the same treatment deferred until an indication occurred, Follow-up and management were otherwise according to the participating clinician's normal practice. Information was collected annually on survival, local and distant progression, and major complications (pathological fracture, spinal cord compression, ureteric obstruction and extra-skeletal metastases). Results Follow-up data were returned on 934 patients; 51 deferred patients died from causes other than prostate cancer before treatment was started (but only five of these presented at age <70 years) and 29 died from prostate cancer before treatment could be started, Treatment was commenced for local progression almost as frequently as for metastatic disease, Progression from M0 to M1 disease (P<0.001, two-tailed) and development of metastatic pain occurred more rapidly in deferred patients; 141 deferred patients needed transurethral resection for local progression compared with 65 treated immediately (P<0.001, two-tailed). Pathological fracture, spinal cord compression, ureteric obstruction and development of extra-skeletal metastases were twice as common in deferred patients. Of the patients who died, 67% did so from prostate cancer; 361 patients died in the deferred arm compared with 328 in the immediate arm (P=0.02, two-tailed), where 257 and 203 were deaths from prostate cancer, respectively (P=0.001 two-tailed). This difference was seen largely in M0 patients, with 119 and 81 deaths from prostate cancer, respectively (P<0.001 two-tailed). Conclusions The results consistently favour immediate treatment, although some of the data, especially on M0 patients, are immature. The implications for management of advanced prostate cancer are discussed

Almond orchards with living ground cover host more wild insect pollinators

Wild pollinators are becoming more valuable to global agriculture as the commercial honeybee industry is increasingly affected by disease and other stressors. Perennial tree crops are particularly reliant on insect pollination, and are often pollen limited. Research on how different tree crop production systems influence the richness and abundance of wild pollinators is, however, limited. We investigated, for the first time, the richness and abundance of potential wild pollinators in commercial temperate almond orchards in Australia, and compared them to potential pollinator communities in proximate native vegetation. We quantified ground cover variables at each site and assessed the value of ground cover on the richness and abundance of potential wild pollinators in commercial almond systems focussing on three common taxa: bees, wasps and flies. More insects were caught in orchards with living ground cover than in native vegetation or orchards without ground cover, although overall species richness was highest in native vegetation. Percent ground cover was positively associated with wasp richness and abundance, and native bee richness, but flies showed no association with ground cover. The strongest positive relationship was between native bee abundance and the richness of ground cover plants. Our results suggest that maintaining living ground cover within commercial almond orchards could provide habitat and resources for potential wild pollinators, particularly native bees. These insects have the potential to provide a valuable ecosystem service to pollinator-dependent crops such as almond