Isotopic Incorporation and the Effects of Fasting and Dietary Lipid Content on Isotopic Discrimination in Large Carnivorous Mammals.

There has been considerable emphasis on understanding isotopic discrimination for diet estimation in omnivores. However, discrimination may differ for carnivores, particularly species that consume lipid-rich diets. Here, we examined the potential implications of several factors when using stable isotopes to estimate the diets of bears, which can consume lipid-rich diets and, alternatively, fast for weeks to months. We conducted feeding trials with captive brown bears (Ursus arctos) and polar bears (Ursus maritimus). As dietary lipid content increased to ∼90%, we observed increasing differences between blood plasma and diets that had not been lipid extracted (∆(13)Ctissue-bulk diet) and slightly decreasing differences between plasma δ(13)C and lipid-extracted diet. Plasma Δ(15)Ntissue-bulk diet increased with increasing protein content for the four polar bears in this study and data for other mammals from previous studies that were fed purely carnivorous diets. Four adult and four yearling brown bears that fasted 120 d had plasma δ(15)N values that changed by <±2‰. Fasting bears exhibited no trend in plasma δ(13)C. Isotopic incorporation in red blood cells and whole blood was ≥6 mo in subadult and adult bears, which is considerably longer than previously measured in younger and smaller black bears (Ursus americanus). Our results suggest that short-term fasting in carnivores has minimal effects on δ(13)C and δ(15)N discrimination between predators and their prey but that dietary lipid content is an important factor directly affecting δ(13)C discrimination and indirectly affecting δ(15)N discrimination via the inverse relationship with dietary protein content.

Endoscopic lumbar discectomy under local anesthesia may be an alternative to microdiscectomy: A single centre's experience using the far lateral approach.

OBJECTIVES: Since the turn of the century, minimally invasive surgery has become increasingly widespread. Discectomy surgery has evolved from wide open to microscopic and now endoscopic. This study aims to demonstrate that transforaminal endoscopic discectomy is an alternative and safe approach for degenerative disk surgery. PATIENTS AND METHODS: Two year retrospective assessments of patients who underwent transforaminal endoscopic discectomy at a tertiary neurosurgical center in the United Kingdom by a single surgeon. Under strict confidentiality, data was collected from online patient data and PACS systems. Patient feedback was achieved using phone call follow up and clinic appointments. Standard statistical analysis was performed. RESULTS: 201 patients had endoscopic discectomy and the mean age was 41 years. Male:female ratio was 1.3:1.0. Mean time of onset of symptoms was 5.5 months and the most common level was L4/5 (53%). All endoscopic discectomies were performed under local anesthesia. Theater time was on average 110 min. 10 patients were lost to follow up. 95% of patients were discharged within 7h post operatively. Visual acuity score of the pain dropped from an average of 7/10 pre-operatively to 0-1/10 in 95% of patients two weeks post operatively. 87% patients went back to their normal daily activities within two weeks. There were no cases of CSF leak, hematoma formation or wound infection. 1% of patients developed a nerve root injury. 6% of patients had recurrent herniation and require microdiscectomy. CONCLUSION: Endoscopic discectomy can be an alternative approach to microdiscectomy. While it can take more expertise to perform endoscopic discectomy, our data shows that the far lateral endoscopic discectomy using the TESSYS technique has comparable outcomes to microdiscectomy.

Paratrigonal choroid plexus papilloma presenting with satellite multiple supra- and infratentorial hemorrhages. Neuroanatomical basis and pathological hypothesis.

INTRODUCTION: Choroid plexus papillomas (CPP) are rare tumors arising from the neuroepithelium of the choroid plexus. PRESENTATION OF CASE: We report a case of a patient operated for a paratrigonal hemorrhagic WHO class I CPP presenting with multiple satellite supra- and infratentorial hemorrhages. Clinical presentation was characterized by sudden hemiparesis, speech impairment and consciousness deterioration; neuroradiological imaging showed a huge contrast-enhanced solid hemorrhagic left paratrigonal lesion along with others multifocal right occipital and vermian hemorrhages. The patient underwent urgent intervention for excision of the paratrigonal lesion, whose histological analysis led to the diagnosis of CPP. A few days later due to failure of conservative treatment of the satellite hemorrhages the patient underwent a second-time surgery for their evacuation; interestingly histological examination of the tissue probe did not reveal any neoplastic features confirming their sole hemorrhagic nature. Patient's conditions slowly improved despite severe neurological deficits, without any further tumor recurrence. DISCUSSION: A thorough revision of the literature is provided including previous reported cases of spontaneous bleeding CPPs and other underlying causes that could lead to multifocal hemorrhages. CONCLUSION: Due to the rarity of these events, this case remains still open to speculative hypotheses drawn to explain the neuroanatomical and pathogenetic basis behind this case report.