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The choroid plexus (CP) is an extensively vascularized neuroepithelial tissue that projects into the brain ventricles. The restriction of transepithelial transport across the CP establishes the blood-cerebrospinal fluid (CSF) barrier that is fundamental to the homeostatic regulation of the central nervous system microenvironment. However, the molecular mechanisms that control this process remain elusive. Here we show that the genetic ablation of Sox9 in the hindbrain CP results in a hyperpermeable blood-CSF barrier that ultimately upsets the CSF electrolyte balance and alters CSF protein composition. Mechanistically, SOX9 is required for the transcriptional up-regulation of Col9a3 in the CP epithelium. The reduction of Col9a3 expression dramatically recapitulates the blood-CSF barrier defects of Sox9 mutants. Loss of collagen IX severely disrupts the structural integrity of the epithelial basement membrane in the CP, leading to progressive loss of extracellular matrix components. Consequently, this perturbs the polarized microtubule dynamics required for correct orientation of apicobasal polarity and thereby impedes tight junction assembly in the CP epithelium. Our findings reveal a pivotal cascade of SOX9-dependent molecular events that is critical for construction of the blood-CSF barrier., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)

Background and Objective: We investigated cerebrospinal fluid characteristics in patients with and without diabetes mellitus and the influences that changes in these characteristics have on sensory and motor block when spinal anaesthesia is performed., Methods: We included 44 patients in each study group. All received spinal administration of 15 mg of 0.5% isobaric bupivacaine. Blood and cerebrospinal fluid were analysed for glucose, total protein, urea, albumin, immunoglobulin G, sodium, chloride, potassium, calcium, magnesium and osmolarity as well as the performance of the local anaesthetic from establishment until complete regression of sensory and motor block., Results: The cerebrospinal fluid of the two groups differed significantly (P < 0.05) in the levels of total protein, albumin, immunoglobulin G, glucose and osmolarity. Sensory and motor block was established more rapidly in the diabetic group (P < 0.05), and the total duration from maximum block until regression to two dermatomes was greater (P < 0.05), as was the complete regression from sensory and motor block (P < 0.05)., Conclusion: This study shows that diabetes mellitus has an influence on sensory and motor block after the administration of spinal isobaric bupivacaine.

CSF samples were taken from 50 healthy pigs of both sexes and cytologically and biochemically examined. With the aid of regression calculations it was investigated, whether deep freezing of CSF samples influences the laboratory results. The parameters glucose, urea, creatinine, total protein, magnesium, anorganic phosphate, AST and AP were in good agreement with the values of the original samples exhibiting only slight variations. Minor age relationship was only seen with respect to the two enzymes LDH and HBDH. A linear relationship was found between values in CSF and in serum of the parameters urea, creatinine, sodium and potassium. CSF examination should include cell count, Pandy's test and bacteriological investigation as well as the determination of the levels of the enzymes LDH and HBDH. The activity of the enzymes AST and ALT increases along with the severity of the tissue damage (meningitis). The specific gravity increases similarly to the total protein level in cases of chronic compression of the spinal cord, and Pandy's test becomes positive. However, CSF glucose levels are partly reduced in animals with central nervous symptoms. The levels of the enzymes AP and CK are often increased in central nervous disturbances, but do not admit drawing a conclusion on the degree of damage.

We describe the chemical values of the normal cerebro-spinal fluid and any variation during meningitis. We also refere the physical peculiarity and the variations of non-proteins-nitrogen, of enzymes, of glucose and its metabolites, of proteins and cells. On the picture we resume the most significative variation for differential diagnosis among bacterial, viral and tuberculous meningitis.

Increases in cerebrospinal fluid pressure (CSFP) were measured in the lateral ventricle in barbiturate anaesthetized male Sprague Dawley rats during intracerebroventricular (IVT) infusions into the contralateral ventricle. IVT infusions of isotonic artificial CSF (art-CSF) solutions at 10 and 38 microliters/hr increased mean CSFP from control preinfusion level of 3.6 cm H2O to 4.6 cm H20 (n.s.) and 5.2 cm H2O (p less than 0.01) respectively with CSFP appearing to attain equilibrium after 30-60 min of infusion. IVT infusion of hyperosmolar art CSF solutions (saccharide and salt solutions of approximate 1000 mOsm/kg) at 38 microliters/hr resulted in a larger increase of CSFP which equilibrated at 8.5 cm H2O (p less than 0.001) after 90 min of infusion. It is suggested that on the basis of CSFP measurements in these and other experiments cited that IVT infusions be run at infusion rates of less than 40 microliters/hr to ensure minimal physiological change.

Methods have been developed for the placement of cannulas in the lateral cerebral ventricle and cisternum magnum of the fetal lamb. Three to seven days after surgery, perfusion of the cerebral ventricular system was carried out in unanesthetized lambs in utero. Artificial cerebrospinal fluid (CSF) was perfused at 123 microliter/min for 4-5 h with no change in fetal arterial O2 pressure, CO2 pressure, pH, mean arterial blood pressure, or heart rate. The preparation is suitable for measurements of net formation of fetal central CSF and also for producing changes in the ionic composition of the fetal CSF.