Negligible In Vitro Recovery of Macromolecules from Microdialysis Using 100 kDa Probes and Dextran in Perfusion Fluid.

Microdialysis is applied in neurointensive care to monitor cerebral glucose metabolism. If recoverable, macromolecules may also serve as biomarkers in brain disease and provide clues to their passage across the blood-brain barrier. Our study aimed to investigate the in vitro recovery of human micro- and macromolecules using microdialysis catheters and perfusion fluids approved for clinical use. In vitro microdialysis of a bulk solution containing physiological or supraphysiological concentrations of glucose, lactate, pyruvate, human IgG, serum albumin, and hemoglobin was performed using two different catheters and perfusion fluids. One had a membrane cut-off of 20 kDa and was used with a standard CNS perfusion fluid, and the other had a membrane cut-off of 100 kDa and was perfused with the same solution supplemented with dextran. The flow rate was 0.3 µl/min. We used both push and push-pull methods. Dialysate samples were collected at 2-h intervals for 6 h and analyzed for relative recovery of each substance. The mean relative recovery of glucose, pyruvate, and lactate was > 90% in all but two sets of experiments. In contrast, the relative recovery of human IgG, serum albumin, and hemoglobin from both bulk solutions was below the lower limit of quantification (LLOQ). Using a push-pull method, recovery of human IgG, serum albumin, and hemoglobin from a bulk solution with supraphysiological concentrations were above LLOQ but with low relative recovery (range 0.9%-1.6%). In summary, exchanging the microdialysis setup from a 20 kDa catheter with a standard perfusion fluid for a 100 kDa catheter with a perfusion solution containing dextran did not affect the relative recovery of glucose and its metabolites. However, it did not result in any useful recovery of the investigated macromolecules at physiological levels, either with or without a push-pull pump system.

Three underdogs among galenic veins: anatomical analysis and literature review of surgical relevant veins in the quadrigeminal cistern.

Recent studies (Alaou-Ismaili et al. 2020; Kilic et al. Eur J Radiol 56:212-219, 2005) among experienced sub-specialized neurosurgeons described divergent perceptions of surgical risk for venous sacrifice in posterior fossa surgery. Three galenic veins stood out as controversial in venous risk assessment and underexplored in the literature: the internal occipital vein (IOV), the precentral cerebellar vein (PCV), and the superior vermian vein (SVV). We have conducted a narrative review based on a systematic literature search to analyze terminology and anatomic descriptions and to suggest a coherent synthesis of published data on these veins. A systematic PubMed literature search was carried out using the keywords: "posterior fossa," "venous anatomy," and "radiology." Relevant radiological, microsurgical, and anatomical articles were selected if they described the anatomy of the three veins. Anatomical descriptions were analyzed with hermeneutic methodology alongside the articles' radiological and anatomical dissection pictures. New illustrations were created to depict the synthesized image of the venous anatomy. A total of 13 articles described the anatomy and terminology of the relevant veins. The descriptions of the IOV included smaller non-occipital vessels that confused the identification of the vessel. IOV is analyzed to be the vein draining the primary visual cortex, which drains into the vein of Galen (VG). The PCV and SVV enter the VG from below and are fused in almost half of all studied patients, creating a third vessel by the name of the superior cerebellar vein. A conscientious narrative review and hermeneutic analysis produced a synthesized, uniform picture of terminology and anatomy. Consensus on anatomical descriptions and definitions are indispensable for validation of anatomy, research into anatomical variation, for surgical planning and documentation.

Relevancy of radiographic features in elbow fractures.

PURPOSE: To correlate radiographic and clinical findings of elbow fractures. MATERIAL AND METHODS: A retrospective study was made of 110 consecutive adult elbow fractures of various types involving the humerus, the ulna, and the radius. RESULTS: Twenty-seven fractures with radiographically conspicuous distortions healed. Of these only 15 had clinical sequelae. Five had clinical sequelae without showing conspicuous radiographic distortions after healing. CONCLUSION: For radiographic evaluation and classification purposes, it would seem to be important to note the status of the capitellum, the capitellum-trochlear plane, and the combination of a distal humerus and a proximal ulna fracture. The outcome of common olecranon fractures and injuries to the radial head would seem to depend less on a detailed radiographic description.