Diazepam-binding inhibitor-like activity in rat cerebrospinal fluid after stimulation by an aversive quinine taste

Cerebrospinal fluid (CSF) taken from rats after stimulation by an aversive quinine taste (hereafter called quinine CSF) administered into the fourth ventricle of mice suppressed their intake of 5% sucrose solution. We examined the effects of CSF on glutathione-induced tentacle ball formation (TBF) of hydra to determine the change in CSF components associated with aversive taste stimuli. The suppressive activity of quinine CSF on TBF in the presence of 3 microM S:-methyl-glutathione (GSM) was markedly lower than that of CSF obtained from control rats (control CSF). Pronase-treated quinine CSF had suppressive activity similar to that of control CSF. The active principle passed through an ultrafiltration membrane, with a molecular weight cut-off of 30 kDa, but not through one with a cut-off of 3 kDa. A peptide fragment of diazepam-binding inhibitor (DBI) nullified the suppression of TBF at 3 microM GSM by control CSF. The nullifying activity of quinine CSF was not observed after treatment with a benzodiazepine receptor preparation that was able to bind DBI. When flumazenil, a benzodiazepine receptor antagonist, was given to mice, the suppression of the intake of 5% sucrose solution by quinine CSF was partially reversed. It is suggested that quinine CSF contains a DBI-like substance.     

Enhanced detection of CNS cell secretome in plasma protein-depleted cerebrospinal fluid

Human cerebrospinal fluid (CSF) proteome is actively investigated to identify relevant biomarkers and therapeutic targets for neurological disorders. Approximately 80% of CSF proteome originate from plasma, yielding a high dynamic range in CSF protein concentration and precluding identification of potential biomarkers originating from CNS cells. Here, we have adapted the most complete multiaffinity depletion method available to remove 20 abundant plasma proteins from a CSF pool originating from patients with various cognitive disorders. We identified 622 unique CSF proteins in immunodepleted plus retained fractions versus 299 in native CSF, including 22 proteins hitherto not identified in CSF. Parallel analysis of neuronal secretome identified 34 major proteins secreted by cultured cortical neurons (cell adhesion molecules, proteins involved in neurite outgrowth and axonal guidance, modulators of synaptic transmission, proteases and protease inhibitors) of which 76% were detected with a high confidence in immunodepleted CSF versus 50% in native CSF. Moreover, a majority of proteins previously identified as secretory products of choroid plexus cells or astrocytes were detected in immunodepleted CSF. Hence, removal of 20 major plasma proteins from CSF improves detection of brain cell-derived proteins in CSF and should facilitate identification of relevant biomarkers in CSF proteome profiling analyses.     

Cerebrospinal fluid glucose and lactate: age-specific reference values and implications for clinical practice

Cerebrospinal fluid (CSF) analysis is an important tool in the diagnostic work-up of many neurological disorders, but reference ranges for CSF glucose, CSF/plasma glucose ratio and CSF lactate based on studies with large numbers of CSF samples are not available. Our aim was to define age-specific reference values. In 1993 The Nijmegen Observational CSF Study was started. Results of all CSF samples that were analyzed between 1993 and 2008 at our laboratory were systematically collected and stored in our computerized database. After exclusion of CSF samples with an unknown or elevated erythrocyte count, an elevated leucocyte count, elevated concentrations of bilirubin, free hemoglobin, or total protein 9,036 CSF samples were further studied for CSF glucose (n = 8,871), CSF/plasma glucose ratio (n = 4,516) and CSF lactate values (n = 7,614). CSF glucose, CSF/plasma glucose ratio and CSF lactate were age-, but not sex dependent. Age-specific reference ranges were defined as 5–95^th percentile ranges. CSF glucose 5^th percentile values ranged from 1.8 to 2.9 mmol/L and 95^th percentile values from 3.8 to 5.6 mmol/L. CSF/plasma glucose ratio 5^th percentile values ranged from 0.41 to 0.53 and 95^th percentile values from 0.82 to 1.19. CSF lactate 5^th percentile values ranged from 0.88 to 1.41 mmol/L and 95^th percentile values from 2.00 to 2.71 mmol/L. Reference ranges for all three parameters were widest in neonates and narrowest in toddlers, with lower and upper limits increasing with age. These reference values allow a reliable interpretation of CSF results in everyday clinical practice. Furthermore, hypoglycemia was associated with an increased CSF/plasma glucose ratio, whereas hyperglycemia did not affect the CSF/plasma glucose ratio.     

Critical evaluation of the biological role of IgM in cerebrospinal fluid in inflammatory and other diseases of the nervous system

In a group of 10,156 patients with neurological diseases, the IgM level was assessed (using laser nephelometry) both in cerebrospinal fluid (CSF) and serum; concentration of other 17 protein fractions was also simultaneously determined: albumin, immunoglobulins, acute phase reactants, complement components, apolipoproteins, proteinase inhibitors and alpha1-microglobulin. Total protein, element counts and glucose level were also evaluated. In patients with normal CSF findings, only limited statistically significant correlations were demonstrated between IgM and other CSF protein fractions while, in the group of patients with pathological CSF findings, significant correlations were found between CSF(IgM) and other immunoglobulins, complement fractions and the rate of intrathecal synthesis of immunoglobulins. Correlations were also found between CSF(IgM) and CSF antithrombin-III and alpha1-microglobulin. Correlations between CSF(IgM) and CSF apolipoproteins support the theory of CNS tissue destruction whenever the concentration of CSF apolipoproteins is elevated. Our data substantially contribute to establishing the diagnosis in patients with neurological diseases; simultaneous measurement of a high number of CSF proteins is becoming inevitable for a reasonable assessment of the CSF Protein Status.     

The impact of blood contamination on the proteome of cerebrospinal fluid

Human cerebrospinal fluid (CSF) is in direct contact with the brain extracellular space. Beside the secretion of CSF by the choroid plexus the fluid also derives directly from the brain by the ependymal lining of the ventricular system and the glial membrane and from blood vessels in the arachnoid. Therefore, biochemical change in the brain may be reflected in the CSF. CSF is a potential source of protein molecular indices of central nervous system function and pathology. However, various amounts of blood contamination in CSF may arise during sample acquisition. The concentration of protein in the CSF is only 0.2 to 0.5% that of blood. Minor contamination of CSF with blood during collection of the fluid may dramatically alter the protein profile confounding the identification of potential biomarkers. We have analyzed CSF and CSF spiked with increasing amounts of whole blood using proteomic techniques. We detected at least four blood specific highly abundant proteins: hemoglobin, catalase, peroxiredoxin and carbonic anhydrase I. These proteins can be used as blood contamination markers for proteomic analysis of CSF. Proteins in blood contaminated CSF samples were less stable compared to neat CSF at 37 degrees C suggesting that blood borne protease may induce protein degradation in CSF during sample acquisition. This analysis was aimed at identification of proteins found primarily in CSF, those found primarily in blood and assessment of the impact of blood contamination on those proteins found in both fluids.     

Spinal and cranial contributions to total cerebrospinal fluid transport

In this study, we quantified cerebrospinal fluid (CSF) transport from the cranial and spinal subarachnoid spaces separately in sheep and determined the relative proportion of total CSF drainage that occurred from both CSF compartments. Cranial and spinal CSF systems were separated by placement of an extradural ligature over the spinal cord between C(1) and C(2). In one approach, two different radiolabeled human serum albumins (HSA) were introduced into the appropriate CSF compartment by a perfusion system (method 1) or as a bolus injection (method 2). Plasma tracer recoveries in conjunction with a mass balance equation were used to estimate CSF transport. In method 3, catheters connected to reservoirs filled with artificial CSF were introduced into the cranial and spinal CSF compartments. Incremental CSF pressures were established in each CSF system, and the corresponding steady-state flow rates were measured. Total CSF drainage ranged from 0.51 to 0.75 ml. h(-1). cmH(2)O(-1). Expressed as a percentage of the total CSF transport, the ratios of cranial-to-spinal clearance estimated from methods 1, 2, and 3 were 75:25, 88:12, and 75:25, respectively. Primarily on the basis of the data derived from methods 1 and 3, we conclude that the spinal subarachnoid compartment has an important role in CSF clearance and is responsible for approximately one-fourth of total CSF transport.     

Automated extraction of canopy shadow fraction using unmanned helicopter-based color vegetation indices

The canopy shadow fraction (CSF) is composed of the fractional area covered by shadowed tree crowns and shadowed backgrounds for a given illumination and view geometry. Since the CSF is related to the canopy biological and structural features, an accurate estimation of the CSF is expected for better understanding of the canopy characteristics. This study explores an algorithm for an automated extraction of the CSF using near-surface remote sensing method. The high-spatial resolution true-color images over different forested canopies were acquired using an unmanned helicopter. For each site, the images of the same target canopy from multiple view zenith angles (VZA) were taken at the principal plane. The digital images were processed to extract the CSF using the color vegetation indices (CVI) combined with an image threshold algorithm. The CSF was measured based on visual interpretation of the grayscale images. For an automated extraction of the CSF, different CVI related to CSF were assessed with Otsu threshold algorithm. A new CVI called the blue deficient index (BDI) was proposed as an indicator of the CSF exploiting the canopy spectral properties. The performance of each automated extraction method was evaluated with comparison to measured CSF. Among the methods assessed under the study, the CSF estimated by the BDI with the Otsu algorithm was found to be most closely related to the measured CSF. After a successful extraction of the CSF, the effect of VZA on CSF was analyzed. The substantial variation of the CSF with respect to the VZA in the principal plane was confirmed for a given solar position.     

Detection of adiponectin in cerebrospinal fluid in humans

Adiponectin circulates in the body in high concentrations, and 100-fold lower amounts were described in the cerebrospinal fluid (CSF) of mice, whereas in humans, contradictory results have been published. To clarify whether adiponectin is present in human CSF and is derived from the circulation, it was determined in human CSF and plasma of 52 nonselected patients. Adiponectin was detected by immunoblot in CSF and was quantified in CSF and serum by ELISA. CSF adiponectin was positively correlated to systemic levels, and the CSF/serum adiponectin ratio was correlated to the CSF/serum albumin ratio. Furthermore, disturbed function of the blood-brain barrier (BBB) was associated with an elevated CSF/serum adiponectin ratio. Adiponectin mRNA was not found in the brain, indicating that adiponectin crosses the BBB and/or the blood-cerebrospinal fluid barrier (BCB). Rat adiponectin with a COOH-terminal tag was injected into the tail vein of rats and was detected 3 h later in CSF. However, CSF adiponectin in humans and rats was approximately 0.1% of the serum concentration and therefore was below the 0.5% expected in the CSF because of the residual leakage of an undisturbed BBB/BCB. Taken together, data from the present study show that adiponectin in human CSF is far below the level expected by the baseline BBB/BCB permeability, indicating that adiponectin enters the brain much less efficiently than albumin, thus supporting recent data that exclude adiponectin transport to the CSF. Additional studies are needed to reveal whether these low levels of adiponectin in CSF have a physiological function.     

Role of amphibian egg transglutaminase in the development of secondary cytostatic factor in vitro

Fresh cytosols extracted from unfertilized amphibian eggs contain a cytostatic factor (CSF) which arrests the cell cycle at metaphase when microinjected into cleaving blastomeres. This CSF is sensitive to Ca²⁺, and is designated primary CSF (1°CSF). During storage of Ca²⁺-containing cytosols at 2°C, stable CSF activity appears, designated secondary CSF (2°CSF). In Rana pipiens egg cytosols, the development of 2°CSF coincides with the formation of a protein complex with a molecular weight above 2,000 kDa, and this large molecule exhibits a high 2°CSF activity when purified (Shibuya and Masui, 1989: Development 106:799–808). The present study shows that both the formation of 2°CSF protein complex and the development of its activity are inhibited by ethylamine and glycine-ethyl-ester (GEE), both known as potent transglutaminase (TGase) inhibitors. An affinity-purified polyclonal antibody raised against mammalian transglutaminase reacts with an approximately 68-kDa protein in fresh egg cytosols, as well as with the 2°CSF protein complex. In cytosols deprived of transglutaminase by immunoprecipitation, neither the development of 2°CSF activity nor the formation of its protein complex can occur. These results indicate that transglutaminase of Rana pipiens eggs is responsible for the formation of 2°CSF, and that transglutaminase itself is incorporated into 2°CSF molecules. Mol. Reprod. Dev. 47:302–311, 1997. © 1997 Wiley-Liss, Inc.     

Effect of Ganglion Blockade on Cerebrospinal Fluid Norepinephrine

The source of norepinephrine (NE) in CSF has been unclear. It has been suggested that CSF NE indicates central neural noradrenergic tone and is determined differently from plasma NE. If CSF NE depended specifically on NE release in the CNS, then interference with ganglionic neurotransmission would be expected to decrease plasma NE but not CSF NE. Hypotension caused by ganglionic blockade might be expected to increase CSF NE reflexively. We infused the ganglion blocker, trimethaphan, intravenously into anesthetized dogs and measured the effects on mean arterial blood pressure (MAP) and on cisterna magna CSF levels of NE. The results were compared with those obtained on administration of saline, clonidine (2 micrograms/kg), yohimbine (0.25 mg/kg), or nitroprusside and with those obtained when hypotension during ganglion blockade was prevented by concurrent treatment with phenylephrine. Trimethaphan decreased MAP by 40%, arterial NE by 64%, and CSF NE by 61%. Nitroprusside administered intravenously to produce the same 40% depressor response increased arterial NE by 612% and CSF NE by 155%. Prevention of ganglion blockade-induced hypotension using phenylephrine did not prevent the decrease in CSF NE caused by trimethaphan, and when phenylephrine was discontinued, the resulting hypotension was not associated with increases in CSF NE. The similar decreases in plasma NE and CSF NE during ganglionic blockade, and the abolition of reflexive increases in CSF NE during hypotension in ganglion-blocked subjects, cast doubt on the hypothesis that CSF NE indicates central noradrenergic tone and are consistent instead with at least partial derivation of CSF NE from postganglionic sympathetic nerve endings.     

Changes in the relationship between cerebrospinal fluid and blood composition produced by ACTH treatment in conscious sheep

It has been proposed that an increase in CSF osmolality could be involved in the genesis of hypertension by activation of central nervous system receptors involved in cardiovascular regulation. ACTH induced hypertension in the sheep is an adrenally dependent model of steroid induced hypertension. This study reports the effect of ACTH administration (20 g/kg/day) for 5 days on the composition of cerebrospinal fluid (CSF) and blood (plasma) in conscious sheep. ACTH increased CSF and plasma osmolality within 24 h associated with parallel increases in both blood and CSF glucose concentrations and plasma and CSF sodium concentration. Plasma potassium fell within 24 h, but CSF potassium did not change over the 5 days of ACTH treatment. Neither calcium nor magnesium changed in either plasma or CSF. CSF phosphate increased and plasma phosphate decreased. CSF and plasma bicarbonate were elevated with ACTH. Plasma chloride decreased after 5 days of ACTH treatment but was not associated with a change in CSF. The relevance of the measured changes in CSF osmolality and composition to the mechanisms involved in the production of ACTH-induced hypertension will be subject of further experimentation.     

CSF bicarbonate regulation in respiratory acidosis and alkalosis.

CSF bicarbonate regulation was studied in respiratory acidosis and alkalosis of 4h duration in antsthetized dogs. PCO2, pH, HCO3, ammonia, and lactate in CSF and arterial and safittal sinus bloof were measured when equal volumes of saline or acetazolamide (8 mg) were injected into lateral cerebral ventricles. The brain CO2 dissociation curve was determined at the end of all experiments. CSF and arterial bicarbonate increased 11.8 and 5.9 meg/l, respectively, in acidosis. Acetazolamide limited the rise in CSF bicarbonate to 4.2 meg/l, and prevented the CSF bicarbonate increase associated with hyperammonemia. During alkalosis CSF bicarbonate fell 6.5 meg/l and CSF lactate increased almost 2 meg/l while arterial bicarbonate fell 5.7 meg/l and lactate remained unchanged. Thus plasma bicarbonate changes account for some of the CSF unchanged. Thus plasma bicarbonate changes account for some of the CSF bicarbonate alterations in respiratory acid-base-disturbances. In acidosis additional CSF bicarbonate is formed by the choroid plexus and glial cells on the inner and outer surfaces of the brain--a reaction catalyzed by the locally present carbonic anhydrase. In alkalosis the greater fall in CSF bicarbonate than blood is due to selective brain and CSF lactic acidosis.     

The regulation of haemopoiesis in long-term bone marrow cultures: I. Role of L-cell CSF

The effects of L-cell conditioned medium which contains granulocyte/macrophage colony stimulating factor (CSF); of highly purified L-cell CSF; and the antiserum directed against L-cell CSF, have been investigated in long-term murine bone marrow cultures. Treatment of cultures with CSF containing conditioned medium led to a rapid decline in haemopoiesis. However, this inhibition of in vitro haemopoiesis is probably caused by materials other than CSF, since the addition of highly purified L-cell CSF had no appreciable effect upon long-term haemopoietic cell proliferation or differentiation. Furthermore, the inhibitory activity of L-cell conditioned medium was not abrogated following neutralization of the CSF activity by CSF antiserum. The direct addition of CSF antiserum did not inhibit granulocyte or macrophage formation. These results suggest that long-term cultures of murine marrow cells may show extensive interactions with stromal cells which are not influenced by exogenous stimulatory or inhibitory factors.     

Quantification of Axonal Damage in Traumatic Brain Injury

Abstract : Diffuse axonal injury is a primary feature of head trauma and is one of the most frequent causes of mortality and morbidity. Diffuse axonal injury is microscopic in nature and difficult or impossible to detect with imaging techniques. The objective of the present study was to determine whether axonal injury in head trauma patients could be quantified by measuring levels of CSF tau proteins. Tau proteins are structural microtubule binding proteins primarily localized in the axonal compartment of neurons. Monoclonal antibodies recognizing the form of tau found in the CSF of head trauma patients were developed by differential CSF hybridoma screening using CSF from head trauma and control patients. Clones positive for head trauma CSF tau proteins were used to characterize this form of tau and for ELISA development. Using the developed ELISA, CSF tau levels were elevated >1,000-fold in head trauma patients (mean, 1,519 ng/ml of CSF) when compared with patients with multiple sclerosis (mean, 0.014 ng/ml of CSF ; p < 0.001), normal pressure hydrocephalus (nondetectable CSF tau), neurologic controls (mean, 0.031 ng/ml of CSF ; p < 0.001), or nonneurologic controls (nondetectable CSF tau ; p < 0.001). In head trauma, a relationship between clinical improvement and decreased CSF tau levels was observed. These data suggest that CSF tau levels may prove a clinically useful assay for quantifying the axonal injury associated with head trauma and monitoring efficacy of neuroprotective agents. Affinity purification of CSF tau from head trauma patients indicated a uniform cleavage of ~ 18 kDa from all six tau isoforms, reducing their apparent molecular sizes to 30-50 kDa. These cleaved forms of CSF tau consisted of the interior portion of the tau sequence, including the microtubule binding domain, as judged by cyanogen bromide digestion. Consistent with these data, CSF cleaved tau bound taxolpolymerized microtubules, indicating a functionally intact microtubule binding domain. Furthermore, epitope mapping studies suggested that CSF cleaved tau proteins consist of the interior portion of the tau sequence with cleavage at both N and C terminals.     

Integrated analysis of the cerebrospinal fluid peptidome and proteome

Cerebrospinal fluid (CSF) is the only body fluid in direct contact with the brain and thus is a potential source of biomarkers. Furthermore, CSF serves as a medium of endocrine signaling and contains a multitude of regulatory peptides. A combined study of the peptidome and proteome of CSF or any other body fluid has not been reported previously. We report confident identification in CSF of 563 peptide products derived from 91 precursor proteins as well as a high confidence CSF proteome of 798 proteins. For the CSF peptidome, we use high accuracy mass spectrometry (MS) for MS and MS/MS modes, allowing unambiguous identification of neuropeptides. Combination of the peptidome and proteome data suggests that enzymatic processing of membrane proteins causes release of their extracellular parts into CSF. The CSF proteome has only partial overlap with the plasma proteome, thus it is produced locally rather than deriving from plasma. Our work offers insights into CSF composition and origin.     

正常麻醉犬动脉血和脑脊液酸碱及电解质值

２０条正常麻醉犬经股动脉插管和枕骨下经皮穿刺在严格隔绝空气情况下，分别取得动脉血和脑脊液（ＣＳＦ）样本，用ＩＬ－１３０３型血气分析仪和Ｂｅｃｋｍａｎ－７００型生化分析仪检测酸碱变量及电解质。通过酶反应分光光度法检测乳酸（Ｌａｃｔ）。应用（Ｎａ＋＋Ｋ＋）－（Ｃｌ－＋Ｌａｃｔ＋ＨＣＯ３－）公式计算阴离子隙（ＡＧ）。经统计学处理结果表明ＣＳＦＰＨ、Ｋ＋、ＡＧ＜动脉血（ｐ＜０．０１）；ＣＳＦＰＣＯ２、ＨＣＯ３－、Ｃｌ－、Ｌａｃｔ＞动脉血（ｐ＜０．０１）；ＣＳＦＮａ＋同动脉血比较无明显差异（ｐ＞０．０５）。     

Granulocyte‐macrophage colony‐stimulating factor antibody suppresses microglial activity: implications for anti‐inflammatory effects in Alzheimer’s Disease and multiple sclerosis

The objective of our study was to determine granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) activity in the brain following GM‐CSF induction. We injected recombinant mouse GM‐CSF into the brains of 8‐month‐old C57BL6 mice via intracerebroventricular injections and studied the activities of microglia, astrocytes, and neurons. We also sought to determine whether an anti‐GM‐CSF antibody could suppress endogenous microglial activity in the C57BL6 mice and could also suppress microglial activity induced by the recombinant mouse GM‐CSF in another group of C57BL6 mice. Using quantitative real‐time RT‐PCR, we assessed microglial, astrocytic, and neuronal activity by measuring mRNA expression of pro‐inflammatory cytokines, GFAP, and the neuronal marker NeuN in the cerebral cortex tissues from C57BL6 mice. We performed immunoblotting and immunohistochemistry of activated microglia in different regions of the brains from control (phosphate‐buffered saline‐injected C57BL6 mice) and experimental mice (recombinant GM‐CSF‐injected C57BL6 mice, GM‐CSF antibody‐injected C57BL6 mice, and recombinant mouse GM‐CSF plus anti‐GM‐CSF antibody‐injected C57BL6 mice). We found increased mRNA expression of CD40 (9.75‐fold), tumor necrosis factor‐alpha (2.1‐fold), CD45 (1.73‐fold), and CD11c (1.70‐fold) in the cerebral cortex of C57BL6 mice that were induced with recombinant GM‐CSF, compared with control mice. Further, the anti‐GM‐CSF antibody suppressed microglia in mice that were induced with recombinant GM‐CSF. Our immunoblotting and immunohistochemistry findings of GM‐CSF‐associated cytokines in C57BL6 mice induced with recombinant GM‐CSF, in C57BL6 mice injected with the anti‐GM‐CSF antibody, and in C57BL6 mice injected with recombinant mouse GM‐CSF plus anti‐GM‐CSF antibody concurred with our real‐time RT‐PCR findings. These findings suggest that GM‐CSF is critical for microglial activation and that anti‐GM‐CSF antibody suppresses microglial activity in the CNS. The findings from this study may have implications for anti‐inflammatory effects of Alzheimer’s disease and experimental autoimmune encephalomyelitis mice (a multiple sclerosis mouse model).     

Inhibition of murine CFU-C by vindesine: restoration of colony growth by colony stimulating factor

Vindesine (VDS) is a new vinca-alkaloid related to vinblastine and vincristine that blocks production of the microtubules in the mitotic phase of the cell cycle. Studies were undertaken to investigate the inhibitory effect of VDS on normal murine bone marrow cell proliferation and the possible interactions between this compound and L-cell derived colony stimulating factor (CSF). One X 10(7) murine bone marrow cells were exposed to various concentrations of VDS, ranging from 0.1 to 1.5 micrograms/ml for 1 h at 37 degrees C. Following this period, the cells were plated in agar in the presence of 100 units of CSF. A dose-dependent inhibition of colony formation was noted with increasing doses of the drugs. To determine whether an increased dose of CSF could overcome the inhibitory effect of VDS, further studies compared colony growth in response to 100 and 200 units of CSF. Virtually no inhibition of colony growth was detected in VDS-treated cells exposed to this higher dose of CSF while a dose-dependent reduction in CFU-C was noted with 100 units of CSF. Preincubation of cells with VDS and CSF prevented the inhibition that occurred with VDS alone. The addition of anti-CSF serum during the preincubation phase abolished the protective effect of CSF. The studies show that short-term exposure of marrow cells to VDS causes a dose-dependent inhibition of in vitro colony formation; this inhibition is prevented by increasing doses of CSF in agar culture or by simultaneous preincubation with CSF. The CSF action appears specific as its protective effect is neutralized by antibody to CSF, suggesting a potential role for CSF in preventing the antimitotic activity of VDS.     

Molecular properties of a granulocyte/macrophage colony-stimulating factor obtained from the serum-free culture of Yoshida sarcoma cell Line YSSF-212T

A granulocyte/macrophage colony-stimulating factor (Peak-1 CSF) was partially purified from the medium of a serum-free culture of Yoshida sarcoma cells (Line YSSF-212T). Its elution position in gel-filtration chromatography corresponded to a molecular weight of about 22,000. The factor had an isoelectric point at pH 4.5 and a sedimentation coefficient of 2.3 S. The major part of its activity was not bound by Concanavalin A-Sepharose. Although CSF activity behaved as a single component in the gel-filtration and isoelectrofocussing procedures, subsequently it was resolved into two species by preparative discontinuous polyacrylamide gel-electrophoresis. This resolution indicates microheterogeneity of the CSF molecule. Oxidation with periodate readily inactivated L . P3-cell CSF, but the YSSF-cell CSF was fairly resistant. Moreover, titration with anti-L cell CSF serum showed a definite difference between L . P3-cell CSF and YSSF-cell CSF.     

The importance of lymphatics in cerebrospinal fluid transport

Despite the fact that the central nervous system parenchyma does not contain lymphatics, extracranial lymphatic vessels play a very important role in volumetric cerebrospinal fluid (CSF) transport. The most important extracranial location at which lymphatics gain access to CSF is in the nasal submucosa after CSF convects through the cribriform plate. At relatively low intracranial pressures (ICPs), the majority of cranial CSF absorption occurs through this pathway. Global CSF transport parameters in the late gestation fetus and adult sheep are very similar, even though significant numbers of arachnoid projections seem to exist only in the adult. Therefore, extracranial lymphatic vessels play an important role in CSF transport before birth and may represent the primary mechanism for CSF absorption in the neonate. Based on these considerations, hydrocephalus may involve reduced CSF transport to, or into extracranial lymphatic absorption sites.