Epidural Blood Patching in Spontaneous Intracranial Hypotension-Do we Really Seal the Leak?

PURPOSE Epidural blood patch (EBP) is a minimally invasive treatment for spontaneous intracranial hypotension (SIH). Follow-up after EBP primarily relies on clinical presentation and data demonstrating successful sealing of the underlying spinal cerebrospinal fluid (CSF) leak are lacking. Our aim was to evaluate the rate of successfully sealed spinal CSF leaks in SIH patients after non-targeted EBP. METHODS Patients with SIH and a confirmed spinal CSF leak who had been treated with non-targeted EBP were retrospectively analyzed. Primary outcome was persistence of CSF leak on spine MRI or intraoperatively. Secondary outcome was change in clinical symptoms after EBP. RESULTS In this study 51 SIH patients (mean age, 47 ± 13 years; 33/51, 65% female) treated with non-targeted EBP (mean, 1.3 EBPs per person; range, 1-4) were analyzed. Overall, 36/51 (71%) patients had a persistent spinal CSF leak after EBP on postinterventional imaging and/or intraoperatively. In a best-case scenario accounting for missing data, the success rate of sealing a spinal CSF leak with an EBP was 29%. Complete or substantial symptom improvement in the short term was reported in 45/51 (88%), and in the long term in 17/51 (33%) patients. CONCLUSION Non-targeted EBP is an effective symptomatic treatment providing short-term relief in a substantial number of SIH patients; however, successful sealing of the underlying spinal CSF leak by EBP is rare, which might explain the high rate of delayed symptom recurrence. The potentially irreversible and severe morbidity associated with long-standing intracranial hypotension supports permanent closure of the leak

The “minimal boundary curve for endothermy” as a predictor of heterothermy in mammals and birds: a review

According to the concept of the “minimal boundary curve for endothermy”, mammals and birds with a basal metabolic rate (BMR) that falls below the curve are obligate heterotherms and must enter torpor. We examined the reliability of the boundary curve (on a double log plot transformed to a line) for predicting torpor as a function of body mass and BMR for birds and several groups of mammals. The boundary line correctly predicted heterothermy in 87.5% of marsupials (n = 64), 94% of bats (n = 85) and 82.3% of rodents (n = 157). Our analysis shows that the boundary line is not a reliable predictor for use of torpor. A discriminate analysis using body mass and BMR had a similar predictive power as the boundary line. However, there are sufficient exceptions to both methods of analysis to suggest that the relationship between body mass, BMR and heterothermy is not a causal one. Some homeothermic birds (e.g. silvereyes) and rodents (e.g. hopping mice) fall below the boundary line, and there are many examples of heterothermic species that fall above the boundary line. For marsupials and bats, but not for rodents, there was a highly significant phylogenetic pattern for heterothermy, suggesting that taxonomic affiliation is the biggest determinant of heterothermy for these mammalian groups. For rodents, heterothermic species had lower BMRs than homeothermic species. Low BMR and use of torpor both contribute to reducing energy expenditure and both physiological traits appear to be a response to the same selective pressure of fluctuating food supply, increasing fitness in endothermic species that are constrained by limited energy availability. Both the minimal boundary line and discriminate analysis were of little value for predicting the use of daily torpor or hibernation in heterotherms, presumably as both daily torpor and hibernation are precisely controlled processes, not an inability to thermoregulate

Nanofabrication of protein-patterned substrates for future cell adhesion experiments

A method for fabricating sub-micrometer size adhesion sites for future experiments in cell biology is presented. Glass substrates were coated with a thin layer of InSnO and SiO2. The SiO2 was structured by means of electron beam lithography and reactive ion etching, exposing sub-micrometer patches of the underlying InSnO. Dodecylphosphate, to which proteins can bind, was selectively adsorbed on these InSnO structures, whereas poly-l-lysine-g-poly(ethylene glycol) was used to passivate the surrounding SiO2 against protein adsorption. The effectiveness of the process was investigated by fluorescent microscopy and scanning near-field optical microscopy on substrates which have been exposed to fluorescently labeled streptavidin

Diving capacity and foraging behaviour of the water shrew (Neomys fodiens)

With regard to semi-aquatic mammals, Schröpfer & Stubbe (1992) distinguished three riparian guilds: the herbivores with the water vole and the beaver; the megacarnivores with the mink and the otter; and the macrocarnivores with water shrews and desmans. Among water shrews, the evolution of aquatic foraging behaviour occurred several times: Nectogale and Chimarrogale in Asia, several species of the genus Sorex in America, and Neomys in Eurasia (Churchfield, 1990). The fairly common European water shrew N. fodiens is the best known. However, the reports on the degree of adaptation to the water habitat are conflicting. Therefore some important findings from the literature are reviewed in this introduction, whereas new data are presented in the following sections. The swimming locomotion of water shrews was analysed by Ruthardt & Schröpfer (1985) and Köhler (1991), and the related morphological adaptation were reviewed by Hutterer (1985) and Churchfield (this volume pp. 49-51). They obviously present a compromise between the requirements for activity on land and in the water. Thermoregulation is a major problem for semi-aquatic mammals, because heat conductance in water is 25-fold greater than in air (Calder, 1969). According to this author, the body temperature of immersed American Sorex palustris dropped by a rate of 2.8 °C per min. However, this may be an experimental artefact, because Neomys fodiens can maintain its body temperature at 37 °C during an immersion of 6 min (Vogel, 1990)