Factors influencing the concentration gradient of protein in cerebrospinal fluid

Rifampicin and protein concentrations in paired spinal versus ventricular cerebrospinal fluid samples of children with tuberculous meningitis

BACKGROUND

Tuberculous meningitis (TBM) is the most lethal form of TB. To study the disease, drug concentrations in samples obtained from the spinal CSF are usually used to reflect brain concentrations. Emerging data suggest that transport of substances across capillaries in the brain (ventricular CSF) and spinal cord may differ.

METHODS

We examined paired, time-linked samples of ventricular CSF (VCSF) and lumbar CSF (LCSF) of 28 patients with TBM and analysed these for rifampicin and total protein concentrations. Clinically indicated samples from procedures to determine the level of CSF block were collected from children being treated for TBM and hydrocephalus. Total protein concentrations were determined using the bicinchoninic acid (BCA) or turbidimetry assay, and rifampicin concentrations were determined using a validated LC coupled with tandem MS method. A paired Wilcoxon signed-rank test was used to determine significance.

RESULTS

TBM was confirmed in 19 cases (68%) using TB culture or GeneXpert Mtb/Rifampicin assay. All other cases were classified as probable. The median total protein concentration in LCSF was 6.0 g/L and in VCSF was 1.3 g/L. The median rifampicin concentration in LCSF was 299 ng/mL and 133 ng/mL in VCSF. The median ratio of LCSF/VSCF for protein was 4.23 and 1.57 for rifampicin.

CONCLUSIONS

Total protein and rifampicin concentrations differed significantly between the two compartments, both being higher in LCSF than in VCSF samples (P < 0.0001 for total protein and P = 0.0046 for rifampicin). Further studies are required to explore the causative reasons for the observed differences.

Ventricular and lumbar cerebrospinal fluid analysis in 77 HIV-negative patients with Cryptococcal meningitis who received a ventriculoperitoneal shunt

Lumbar cerebrospinal fluid (CSF) parameters are widely studied and have wide clinical applications, but ventricular CSF has rarely been studied since it is relatively difficult to obtain. To determine whether there are differences between ventricular and lumbar CSF parameters and whether the differences have clinical significance, we retrospectively reviewed 77 patients with Cryptococcal meningitis who received a ventriculoperitoneal shunt. We analyzed the following parameters: white blood cell count, total protein concentration, CSF/blood glucose ratio, chloride ion concentration, and Cryptococcal count. All parameters between lumbar and ventricular CSF were remarkably different (all p < 0.001). White blood cell count, total protein level and Cryptococcal count were lower in ventricular CSF than in lumbar CSF, while CSF/blood glucose ratio and chloride ion concentration were higher. Compared to patients without ventriculomegaly, patients with ventriculomegaly had a significantly higher total protein concentration in ventricular CSF (p = 0.047). Compared to patients without surgical complications, patients with complications had a significantly lower CSF/blood glucose ratio in ventricular CSF (p = 0.032). The lumbar CSF parameters had no significant differences between these groups. The changes in lumbar CSF indices over time after shunt placement were also analyzed. After shunt placement, total protein concentration was transiently increased, white blood cell count, CSF/blood glucose ratio and chloride ion concentration were continued at the preoperative level until two months after shunting surgery. These findings suggest that the composition of ventricular CSF differs from that of lumbar CSF, and different CSF parameters have disparate rostro-caudal gradients in patients with Cryptococcal meningitis. Furthermore, ventricular and lumbar CSF parameters may have different clinical implications. Transient deterioration of lumbar CSF parameters after ventriculoperitoneal shunt placement may not be due to disease progression, but to change in CSF flow rate by CSF shunts.

Spatial and temporal variation of routine parameters: pitfalls in the cerebrospinal fluid analysis in central nervous system infections

The cerebrospinal fluid (CSF) space is convoluted. CSF flow oscillates with a net flow from the ventricles towards the cerebral and spinal subarachnoid space. This flow is influenced by heartbeats, breath, head or body movements as well as the activity of the ciliated epithelium of the plexus and ventricular ependyma. The shape of the CSF space and the CSF flow preclude rapid equilibration of cells, proteins and smaller compounds between the different parts of the compartment. In this review including reinterpretation of previously published data we illustrate, how anatomical and (patho)physiological conditions can influence routine CSF analysis. Equilibration of the components of the CSF depends on the size of the molecule or particle, e.g., lactate is distributed in the CSF more homogeneously than proteins or cells. The concentrations of blood-derived compounds usually increase from the ventricles to the lumbar CSF space, whereas the concentrations of brain-derived compounds usually decrease. Under special conditions, in particular when distribution is impaired, the rostro-caudal gradient of blood-derived compounds can be reversed. In the last century, several researchers attempted to define typical CSF findings for the diagnosis of several inflammatory diseases based on routine parameters. Because of the high spatial and temporal variations, findings considered typical of certain CNS diseases often are absent in parts of or even in the entire CSF compartment. In CNS infections, identification of the pathogen by culture, antigen detection or molecular methods is essential for diagnosis.

Comparison of Lumbar and Ventricular Cerebrospinal Fluid for Diagnosis and Monitoring of Meningitis

Severe meningitis, especially basilar meningitis, can lead to hydrocephalus requiring external ventricular drain (EVD) placement. There are differences in cerebrospinal fluid (CSF) obtained from an EVD compared to a lumbar puncture (LP). Hence, it becomes difficult to compare LP and EVD samples for diagnosis and monitoring of meningitis. Recognizing these differences is important to properly treat and discontinue antibiotics. We report a case series of 6 patients with meningitis comparing EVD and LP CSF study analysis. In all 6 patients, CSF from LP was obtained before EVD placement by 1.7 days on average. Although corrected white blood cell (WBC) counts were elevated in CSF obtained from LP and EVD, the counts were significantly higher in LP CSF. Protein concentration in LP CSF was also significantly higher than EVD CSF. Glucose and red blood cells varied in both LP and EVD samples. Even though EVD CSF was obtained later in the clinical course than LP, slower circulation of CSF in lumbar space as compared to ventricles is likely the reason for a more sterile appearance of EVD CSF for the diagnosis of meningitis. It is important to recognize these differences as EVD CSF analysis for diagnosis of meningitis may lead to a missed diagnosis and false perception of significant improvement when monitoring response to treatment. One can consider repeating LP prior to discontinuation of antibiotics to properly determine the extent of improvement given EVD CSF sample appears more sterile in comparison. Larger studies are needed to confirm the above findings.

Soluble protein tyrosine phosphatase receptor type Z (PTPRZ) in cerebrospinal fluid is a potential diagnostic marker for glioma

Background

High-grade glioma is the most pervasive and lethal of all brain malignancies. Despite advances in imaging technologies, discriminating between gliomas and other brain diseases such as multiple sclerosis (MS) often requires brain biopsy. Several reports show that protein tyrosine phosphatase receptor Z (PTPRZ) is highly expressed in glioblastoma, and we found that a soluble cleaved form of PTPRZ (sPTPRZ) was present in the cerebrospinal fluid (CSF). The aim of this study was to determine whether the sPTPRZ level in CSF has utility as a diagnostic marker for glioma.

Methods

Microarray datasets from normal brain tissue and brain tumors were obtained from the Gene Expression Omnibus. PTPRZ protein expression in clinical specimens was evaluated by immunohistochemistry. Semiquantitative western blotting was used to measure sPTPRZ levels in CSF samples from patients with glioma, schwannoma, MS, or nontumor disorders.

Results

Expression of PTPRZ mRNA and protein was markedly increased in glioblastoma, astrocytoma, oligodendroglioma, and schwannoma tissues compared with control brain tissue. sPTPRZ was present at significantly elevated levels in the CSF of patients with glioma (grades 1–4), but not in patients with schwannoma or MS, compared with the control samples. Receiver operating characteristic curve analysis showed that sPTPRZ in CSF could discriminate between glioma and MS patients (area under the curve 0.9676; P < .0001).

Conclusions

sPTPRZ in CSF is a promising diagnostic biomarker for glioma and could reduce the need for a surgical biopsy.

Glymphatic solute transport does not require bulk flow

Observations of fast transport of fluorescent tracers in mouse brains have led to the hypothesis of bulk water flow directed from arterial to venous paravascular spaces (PVS) through the cortical interstitium. At the same time, there is evidence for interstitial solute transport by diffusion rather than by directed bulk fluid motion. It has been shown that the two views may be consolidated by intracellular water flow through astrocyte networks combined with mainly diffusive extracellular transport of solutes. This requires the presence of a driving force that has not been determined to date, but for which arterial pulsation has been suggested as the origin. Here we show that arterial pulsation caused by pulse wave propagation is an unlikely origin of this hypothetical driving force. However, we further show that such pulsation may still lead to fast para-arterial solute transport through dispersion, that is, through the combined effect of local mixing and diffusion in the para-arterial space.

Interactions between Flow Oscillations and Biochemical Parameters in the Cerebrospinal Fluid

The equilibrium between the ventricular and lumbar cerebrospinal fluid (CSF) compartments may be disturbed (in terms of flow and biochemistry) in patients with chronic hydrocephalus (CH). Using flow magnetic resonance imaging (MRI) and CSF assays, we sought to determine whether changes in CSF were associated with biochemical alterations. Nine elderly patients with CH underwent phase-contrast MRI. An index of CSF dynamics (Idyn) was defined as the product of the lumbar and ventricular CSF flows. During surgery, samples of CSF were collected from the lumbar and ventricular compartments and assayed for chloride, glucose and total protein. The lumbar/ventricular (L/V) ratio was calculated for each analyte. The ratio between measured and expected levels (Ibioch) was calculated for each analyte and compared with Idyn. Idyn varied from 0 to 100.10(3)μl(2).s(2). In contrast to the L/V ratios for chloride and glucose, the L/V ratio for total protein varied markedly from one patient to another (mean ± standard deviation (SD): 2.63 ± 1.24). The Ibioch for total protein was strongly correlated with the corresponding Idyn (Spearman's R: 0.98; p < 5 × 10(-5)).We observed correlated alterations in CSF flow and biochemical parameters in patients with CH. Our findings also highlight the value of dynamic flow analysis in the interpretation of data on CSF biochemistry.

Large and giant vestibular schwannomas: does cisterna magna hyperproteinorrhachia influence visual status?

BACKGROUND

Hyperproteinorrhachia associated with vestibular schwannomas (VSs) may influence visual status independent of the effect caused by raised intracranial pressure. The role of cisterna magna CSF protein levels (CMCP) in determining visual outcome in patients with large to giant vestibular schwannomas (VSs) was prospectively investigated.

METHODS

The mean CMCP levels in VSs and control group; and, levels in VSs with or without visual deterioration were compared. Spearman's rank correlation coefficient tested for relationships between CMCP level with symptom duration and tumour volume (Kawamoto's method). Vision was regarded as normal when visual acuity was >6/18; and, deteriorated when it was between 6/18 and PL negative in the worse eye. Papilloedema (n = 26)/secondary optic atrophy (n = 6) and hydrocephalus (based on Evan's ratio, mild to moderate: n = 22; none: n = 18) were also recorded. The analysis of factors predicting diminished vision was done using logistic regression analysis (p < 0.05 significant).

FINDINGS

There was a significant difference (p < 0.001) in mean CMCP levels between VS (456.3 SD 213.6 mg/dl) and control groups (96.3 SD 74.3 mg/dl). The mean CMCP levels in the VS group were also markedly higher than the ventricular mean protein levels. The CMCP levels in patients with visual diminution (<6/18 to PL negative; n = 23) was 561.4 SD 186.9 mg/dl and those without visual loss (n = 17) was 314.2 SD 160.8 mg/dl (p < 0.001). Their grade of visual diminution had a positive correlation with mean CMCP levels (p < 0.001). There was a negative correlation between total duration of symptoms and CMCP levels (p < 0.015). Logistic regression analysis using five independent factors (symptom duration, papilloedema/secondary optic atrophy, tumour volume, hydrocephalus and mean CMCP level) revealed that only CMCP level had a significant association with visual diminution.

CONCLUSION

Elevated cisternal CSF proteins may play an important role in determining visual outcome in large to giant VSs. Ventricular CSF analysis is often unable confirm the presence of VS-associated cisternal hyperproteinorrhachia. High CMCP levels may influence decision-making while instituting a permanent CSF diversion for postoperative hydrocephalus or recalcitrant pseudomeningocoele.

ETIOPATHOLOGICAL FACTORS RELATED TO HYDROCEPHALUS ASSOCIATED WITH VESTIBULAR SCHWANNOMA

OBJECTIVE

We retrospectively analyzed various clinical factors to determine whether or not these factors are etiopathologically related to the development of hydrocephalus in patients with vestibular schwannomas.

METHODS

There were 68 patients (29 men, 39 women) in this study who underwent resection of a vestibular schwannoma. The age at the time of surgery ranged from 19 to 76 years (mean age, 51.4 yr). The maximum diameter of the tumor in the cerebellopontine cistern ranged from 0 (localized within the internal auditory canal) to 56 mm (mean, 32.0 ± 12.9 mm). Cerebrospinal fluid (CSF) protein concentration in the cerebellomedullary cistern was measured intraoperatively in all patients.

RESULTS

Sixteen (23.5%) of the 68 patients exhibited radiographic evidence of hydrocephalus. Univariate analysis of various factors revealed that both tumor size and CSF protein concentration were positively related to development of hydrocephalus (P &lt; 0.05 and P &lt; 0.01, respectively). However, in multiple logistic regression analysis, only the CSF protein concentration was predictive for development of hydrocephalus (P = 0.022). There was a trend toward increased CSF protein concentration in patients with a large tumor (≥40 mm) compared with those with a small tumor (&lt;40 mm) (P = 0.06).

CONCLUSION

A high CSF protein concentration in fluid from the cerebellomedullary cistern is one of the most important factors contributing to hydrocephalus associated with vestibular schwannoma. It is important to judge whether or not any further treatment is required for hydrocephalus, in addition to tumor resection, especially in patients with communicating hydrocephalus.

Osmotherapy for elevated intracranial pressure: a critical reappraisal

The administration of osmotic agents is one of the principal strategies to lower elevated intracranial pressure (ICP) and to increase cerebral perfusion pressure. Of the 3 osmotic agents frequently used (mannitol, glycerol and sorbitol), each has characteristic advantages and disadvantages. In addition to renal filtration, sorbitol [elimination half-life (t1/2beta) approximately 1h] and glycerol (t1/2beta 0.2 to 1h) are metabolised, mainly by the liver. The risk of these compounds accumulating in patients with renal insufficiency is low. However, both compounds frequently affect glucose metabolism, leading to an increase in the serum glucose concentration. Mannitol is almost exclusively renally filtered and possesses the slowest elimination from serum (t1/2beta 2 to 4h). The t1/2beta of mannitol is markedly increased in patients with renal insufficiency, but it does not interfere with glucose metabolism. Entry into the cerebrospinal fluid (CSF) is highest with glycerol [CSF: serum ratio of the areas under the concentration-time curves (AUC(CSF): AUCs) approximately 0.25], intermediate with mannitol (AUC(CSF): AUCs approximately 0.15) and lowest with sorbitol (AUC(CSF): AUCs approximately 0.10). The elimination of all osmotic agents from the CSF compartment is substantially slower than from serum. During the elimination phase, the CSF-to-serum osmotic gradient is temporarily reversed. This is one cause of the paradoxical rise of ICP above the pretreatment level sometimes observed with osmotherapeutics. The ability of mannitol, glycerol and sorbitol to lower elevated ICP has been extensively documented. However, whether the use of osmotic agents, particularly with repeated application, improves outcome remains unproven. Therefore, these agents should only be used to treat manifest elevations of ICP, not for prophylaxis of brain oedema.

Pharmacokinetic optimisation of the treatment of bacterial central nervous system infections

Central nervous system (CNS) infections caused by bacteria with reduced sensitivity to antibacterials are an increasing worldwide challenge. In successfully treating these infections the following conditions should be considered: (i) Antibacterials do not distribute homogeneously in the central nervous compartments [cerebrospinal fluid (CSF), extracellular space of the nervous tissue, intracellular space of the neurons, glial cells and leucocytes]. Even within the CSF, after intravenous administration, a ventriculo-lumbar concentration gradient is often observed. (ii) Valid parameters of drug entry into the CSF are the CSF: serum concentration ratio in steady state and the CSF: serum ratio of the area under the concentration-time curves (AUCCSF/AUCS). Frequently, the elimination half-life (t1/2 beta) in CSF is longer than t1/2 beta in serum. (iii) For most antibacterials, lipophilicity, molecular weight and serum protein binding determine the drug entry into the CSF and brain tissue. With an intact blood-CSF and blood-brain barrier, the entry of hydrophilic antibacterials (beta-lactam antibacterials, glycopeptides) into the CNS compartments is poor and increases during meningeal inflammation. More lipophilic compounds [metronidazole, quinolones, rifampicin (rifampin) and chloramphenicol] are less dependent on the function of the blood-CSF and blood-brain barrier. (iv) Determination of the minimal inhibitory concentrations (MIC) of the causative organism is necessary for optimisation of treatment. (v) For rapid sterilisation of CSF, drug concentrations of at least 10 times MIC are required. The minimum CSF concentration: MIC ratio ensuring successful therapy is unknown. Strategies to achieve optimum antibacterial concentrations in the presence of minor disturbances of the blood-CSF and blood-brain barrier include, the increased use of low toxicity antibacterials (e.g., beta-lactam antibiotics), the use of moderately lipophilic compounds, and the combination of intravenous and intraventricular administration. Antibacterials which do not interfere with bacterial cell wall synthesis delay and/or decrease the liberation of proinflammatory bacterial products, delay or inhibit tumour necrosis factor release, and may reduce brain oedema in experimental meningitis. Conclusive evidence of the reduction of neuronal damage by this approach, however, is lacking.

Kinetics of piperacillin and tazobactam in ventricular cerebrospinal fluid of hydrocephalic patients

Its broad antibacterial spectrum qualifies the combination of piperacillin and tazobactam for therapy of nosocomial bacterial central nervous system (CNS) infections. Since these infections sometimes are accompanied by only minor dysfunction of the blood-cerebrospinal fluid (CSF) barrier, patients with noninflammatory occlusive hydrocephalus who had undergone external ventriculostomy were studied (n = 9; age range, 48 to 75 years). After administration of the first dose of piperacillin (6 g)-tazobactam (0.5 g) over 30 min intravenously, serum and CSF were drawn repeatedly and analyzed by high-performance liquid chromatography. Pharmacokinetics were determined by noncompartmental analysis. Maximum concentrations of piperacillin in CSF ranged from 8.67 to <0.37 mg/liter (median, 3.42 mg/liter), and those of tazobactam ranged from 1.37 to 0.11 mg/liter (median, 0.45 mg/liter). CSF maxima were observed, in median, 1.5 and 2 h after the end of the infusion. Elimination in CSF was considerably slower than in serum (median half-life at beta phase for piperacillin, 5.9 h in CSF versus 1.47 h in serum; for tazobactam, 6.1 h versus 1.34 h). For tazobactam, the ratio of the area under the concentration-time curve (AUC) in CSF to the AUC in serum was approximately three times as high as that for piperacillin (medians, 0.106 versus 0.034). In view of the tazobactam concentrations in CSF observed in this study, the practice of using a constant concentration of 4 mg of tazobactam per liter for MIC determination is inadequate for intracranial infections. Larger amounts of tazobactam than the standard dose of 0.5 g three times daily may be necessary for CNS infections.

Estimation of steady state antibiotic concentration in cerebrospinal fluid from single-dose kinetics

OBJECTIVE

Assuming linear kinetics, the mean CSF concentrations of an antibacterial in steady state (CssCSF) can be estimated, when the area under the concentration-time curve in CSF after the first dose is known. For this purpose we propose the function CssCSF = AUCCSF.Anticipated dose/Dosing Interval. Applied dose.

RESULTS

Together with the MIC and MBC of the causative pathogen, the estimate is of value in the choice of antibacterial drug and the dosing regimen in central nervous system infections.

An evaluation of human neurophysin production in Alzheimer's disease: preliminary observations

The concentrations of human neurophysins in the cerebrospinal fluid (CSF) of nine patients with Alzheimer's disease: Preliminary observations. (AD), and one patients with Pick's disease, were determined using specific radioimmunoassays (RIAs). Concentrations of vasopressin and oxytocin were also measured. Values were compared with those from 20 age-matched mentally normal individuals who were being treated for back pain. CSF levels of vasopressin-associated human neurophysin (VP-HNP) and oxytocin-associated human neurophysin (OT-HNP) in patients with AD (22 +/- 4 fmol/ml and 104 +/- 17 fmol/ml) were only 42% and 58% of those in the control subjects (p less than 0.0001, p less than 0.0004). Vasopressin levels for these patients (3.6 +/- 0.4 fmol/ml) were also significantly reduced to 51% of controls (p less than 0.007) and oxytocin levels were marginally (p = 0.092) reduced to 70% of controls. Because neurophysins and neuropeptides are gene-related products of vasopressin-neurons and oxytocin-neurons, the data indicate that these neurons are functionally impaired in patients with AD. Plasma neurophysin values suggest this impairment is confined to neurons with centrally-directed axons. Data from the one patient with Pick's disease demonstrates that reduced CSF levels of neurophysins and hormones is not confined to Alzheimer-type dementia.

Discontinuous distribution of IgG oligoclonal bands in cerebrospinal fluid from multiple sclerosis patients

To test the effect of sampling on the detection of immunoglobulin (Ig) cerebrospinal fluid (CSF) abnormalities, we analyzed the first and last 1 ml fraction of 10 ml obtained during a single CSF removal from 27 multiple sclerosis (MS) patients and six patients with other neurological diseases. IgG index, hyperbolic function, and IgG synthesis rate decreased between the first and the last CSF aliquot. Discordant results were found in 4/27 (15%) MS patients. In 2/27 (7.5%) clinically definite MS patients, the number of CSF oligoclonal bands (OCB) decreased between the first and the last fraction. In one of the two patients, the three OCB visualized in the first fraction were not found in the last. We conclude that fractionated sampling may partially account for the absence of OCB in the CSF of some definite MS patients.

Laboratory investigation of cerebrospinal fluid proteins

Analysis of CSF proteins is useful in the diagnosis and management of neurological diseases in the following situations: 1. In inflammatory conditions when there is breakdown of blood-CSF barrier integrity. Meningitis is a medical emergency, with CSF total protein measurement being only a screening test. 2. In the detection of immune responses within the CNS. This is by far the most important application in a routine clinical setting, as it is now a firmly established criterion in the diagnosis of multiple sclerosis. Oligoclonal bands restricted to the CSF are the only reliable indicators of intrathecal immunoglobulin G synthesis and are practically always associated with inflammatory disease of the CNS. The method fo choice for detecting oligoclonal bands is isoelectric focusing with immunofixation. Quantitative measurement of IgG in the CSF is of no value in diagnostic pathology. 3. In destructive brain diseases when brain-specific proteins are released into the CSF, measurement of these proteins can give prognostic information.

Cerebrospinal fluid immunoreactive substance P and somatostatin in neurological patients with peripheral and spinal cord disease

We have measured substance P-like (SPLI) and somatostatin-like (SLI) immunoreactivities in cerebrospinal fluid of 49 patients with peripheral (polyneuropathy, lumboischialgia) and spinal cord disease and in 16 control patients. The patient groups showed significantly higher CSF SPLI levels than controls while the mean SLI levels were unchanged. Fractionated sampling of CSF (total volume 30 ml) in 20 patients with various neurological diseases showed no significant differences between early and late fractions for SLI. In contrast, lumbar-cisternal concentration gradients were negative for SPLI, total protein and IgG, and positive for the dopamine metabolite homovanillic acid and the serotonin metabolite 5-hydroxyindolacetic acid. This suggests that SPLI may be released into the lumbar CSF from lower levels of the neuraxis, presumably the spinal cord and spinal ganglia, whereas SLI stems from diffuse CSF secretion without spinal preponderance.

Assay of immune complexes in infantile hydrocephalus among Nigerians

The immune complexes in infantile hydrocephalic CSF in Nigerian children using a laser nephelometer were quantified. The values obtained were relatively low when compared with the serum levels. There was no evidence of selective admixture or of a breakdown of blood-brain-barrier (BBB). The low levels of immune complexes, when associated with implantation of shunt device for treatment of the hydrocephalus, may be a predisposing factor that can lead to overwhelming infection among this group of patients in a developing country like Nigeria. Between the hydrocephalic fluid and lumbar CSF, an IgG gradient was found.

Dementia--and adenylate kinase activity in cerebrospinal fluid

Adenylate kinase (AK) was determined in a lumbo-cisternal cerebrospinal fluid (CSF) gradient and in CSF from patients with mental deterioration. AK activity was unchanged in the gradient and different from albumin and albumin ratio (alb CSF/albumin serum), a blood-brain barrier marker in the same gradient. No differences between normal pressure hydrocephalus, multiinfarct dementia and dementia of the Alzheimer type could be found with regard to adenylate kinase activity in CSF.

[Ventriculo-lumbar gradient of concentration of total cerebrospinal fluid proteins: 1 - mechanisms of origin]

In normal conditions there is a concentration gradient of proteins along the neuraxis. From a low level in the ventricles, ranging from 5 to 15 mg/10C ml, to an intermediate level in the cisterna magna, the protein content reaches its highest level in the lumbar sac, 12 to 44 mg/100 ml. Several mechanisms were considered to elucidate the origin of this gradient but many investigators think that the progressive increase of the protein concentration is best explained by the transfer of proteins from serum to the cerebrospinal fluid due to the relatively raised permeability of blood-cerebrospinal fluid barrier in the spinal subarachnoid space. This paper presents a study of the protein concentrations in cisternal and lumbar cerebrospinal fluid samples of patients with neurocysticercosis in activity. The 11 patients of the first group had free subarachnoid space communication between the cisterna magna and the lumbar sac; the 6 patients of the second group had a complete block of the subarachnoid space between these two levels. In every cerebrospinal fluid specimen the quantitative complement fixation test for cysticercus was performed and the titer determined in order to make an assessment of the central nervous system humoral immune response. The analysis of the data of this investigation shows that the concentration gradient of proteins is evident in the cerebrospinal fluid of patients with patency of the spinal subarachnoid space, and the ratio of concentrations of protein contents in simultaneous cisternal and lumbar samples was similar to that one observed in normal individuals. This gradient is also detected when the intensity of the humoral immune response is determined by quantitative complement fixation test for cysticercus in simultaneous cisternal and lumbar specimens. After the onset of spinal subarachnoid block, the confront of the results of the tests in cerebrospinal fluid samples, obtained before and after the blockage, shows a large increase both in the total protein content as well as the intensity of the humoral immune response, in the lumbar level. The similar increases both in protein concentration and titer of cysticercus complement fixation test in the lumbar fluid, in comparison with the cisternal fluid, in patients with patent spinal subarachnoid space, and the large simultaneous and similar increases in both protein content and titer of the cysticercus complement fixation test in the lumbar fluid of patients with spinal subarachnoid block are in disagreement with the usual explanation of the origin mechanisms of the gradient.(ABSTRACT TRUNCATED AT 400 WORDS)

The influence of the choroid plexus on the concentration of prealbumin in CSF

Prealbumin and albumin concentrations were measured in homogenates of choroid plexus, ventricular and lumbar CSF, and in serum. The passive permeability-independent prealbumin concentration was estimated by subtracting from the total concentration that portion which enters the plexus and CSF by a passive molecular sieve effect, assuming that the diffusion of albumin and prealbumin is similar. The passive permeability-independent prealbumin concentration was highest in homogenates of the choroid plexus (mean = 56 micrograms/g). It was almost 3 times that in ventricular CSF (mean = 18 micrograms/ml). The passive permeability-independent concentration decreased only slightly during passage from the ventricular to the lumbar CSF space (mean = 16 micrograms/ml). These data suggest that much of the prealbumin in CSF enters the ventricular CSF via the choroid plexus by a mechanism different from that responsible for the transit of albumin.

Separation of cerebrospinal fluid-enriched proteins. A methodological study, Part 2

Beta-trace protein, beta2-microglobulin and prealbumin were identified in a cerebrospinal fluid fraction containing proteins enriched in CSF-characteristic proteins obtained through affinity chromatography. The prealbumin amount was somewhat higher among CSF-enriched proteins from ventricular CSF than in the same fraction from lumbar CSF. Otherwise no variations in the CSF-enriched protein pattern were found in a ventriculo-spinal CSF-gradient analysed with isoelectric focusing. Affinity chromatography was done using insolubilized antisera against human serum proteins or against human cerebrum. Soluble brain proteins were analysed similarly and compared to the CSF-enriched protein pattern.

Neoplastic meningitis. Marked variations of cerebrospinal fluid composition in the absence of extradural block

Cerebrospinal fluid levels of protein, glucose, and malignant cells may differ markedly at different levels of the neuraxis in patients with neoplastic meningitis, even in the absence of an extradural blockage to cerebrospinal fluid flow. The pathogenesis of these differences is unclear, but is probably related to focal disruption of the blood-cerebrospinal fluid barrier produced by neoplastic involvement of the meninges. The clinical implications of this new observation are important. When the diagnosis of neoplastic meningitis is strongly suspected, but malignant cells cannot be demonstrated by repeated examination of lumbar cerebrospinal fluid, samples should be obtained by cisternal tap if the neurologic deficits are manifestations from involvement of the cranial nerves or cerebrum. Similarly, response to intrathecal chemotherapy should be monitored with serial examinations of cerebrospinal fluid obtained from the site of most marked pretreatment abnormality.

Cerebrospinal fluid protein findings in cervical syndromes classified by myelography, and in multiple sclerosis

Determinations of cerebrospinal fluid (CSF) albumin, IgG, albumin blood brain barrier (BBB) permeability and local IgG synthesis indexes in CNS were carried out on 85 patients with various neck, shoulder and upper extremity pain syndromes. CSF was obtained by lumbar puncture in 29, and by lateral neck puncture in 56 of the patients. The patients were classified into 3 different groups according to varying severity of degenerative changes, or cavitation verified by myelography. CSF protein patterns in these patients were compared with lumbar CSF findings in 18 patients with multiple sclerosis. CSF protein changes in patients with abnormal myelographic findings were slight. Protein values were clearly more abnormal in lumbar CSF than in cervical CSF, probably due to a retardation of the CSF flow. Only 3 of 62 patients with a narrowing of the cervical spinal canal had pathological values for IgG synthesis or BBB permeability indexes. On the other hand 14 of 18 patients with multiple sclerosis had abnormal, high values for the IgG index. Thus the present results suggest that investigation of the CSF protein pattern has value in differential diagnosis between patients with multiple sclerosis and degenerative diseases of the cervical spine.

Protein fractions of lumbar, cisternal, and ventricular cerebrospinal fluid. Separate areas of reference

Ventricular (n=27), cisternal (n=33) and lumbar (n=127) cerebrospinal fluid of "non-diseased" reference persons was investigated. The following measurements were taken: (1) Total protein, albumin, immunoglobulin A,G, M (IgA,G,M) in unconcentrated cerebrospinal fluid (CSF). (2) Protein fractions in the microzone electrophoresis of concentrated CSF. Albumin and IgG concentrations were highly correlated in all the samples, regardless of their origin. Therefore, bivariate areas of reference as well as interdependent regression coefficients were computed for the paired data. The regression lines of the 3 different areas of reference (ventricular, cisternal, lumbar) ran parallel to each other, displaced along the axis of the IgG concentration: approximately 10% of the lumbar IgG does not originate directly from serum. Although the albumin concentration increased 2.2 times, and the IgG 2.6 times, from ventricular to lumbar region, the concentration of pre-albumin decreased by a factor of 0.7. The concentration of IgA never surpassed the limits of detection set by this method (8 mg/I), in spite of its similarity to IgG regarding molecular weight and size. The observations strengthen the assumption that selective functions are present at the blood-CSF barrier. In 4 illustrative cases with a chronic inflammatory process, the discriminating power of the different reference areas was demonstrated. The findings should be evaluated in a multivariate manner, considering the location from which the sample was obtained.

Globulina beta do líquido cefalorraqueano no prognóstico de processos inflamatórios do sistema nervoso central

Foi feita avaliação do comportamento da globulina beta do LCR em processos inflamatórios do SNC e/ou de seus envoltórios no sentido de verificar até que ponto podem ser úteis para o prognóstico as informações obtidas. Essa avaliação foi baseada no fato de a concentração dessa globulina no LCR estar relacionada ao metabolismo do parênquima nervoso, aumentando em condições que acarretem seu sofrimento. Os proteinogramas do LCR de 45 pacientes com processos inflamatórios do SNC e/ou de seus envoltórios, distribuídos em 6 grupos de casos, foram analisados segundo a possibilidade de o processo inflamatório estar acarretando, ou não, sofrimento do parênquima encefálico. A análise dos resultados mostrou que o estudo da concentração da globulina beta no LCR fornece elementos que permitem avaliar o comprometimento do parênquima encefálico nessas condições, aduzindo dados úteis para a avaliação prognóstica. A intensidade do aumento da concentração dessa globulina no LCR era maior do que a do aumento da concentração de albumina nos casos em que o processo inflamatório determinava comprometimento do parênquima encefálico.