Effects of moderate alcohol consumption on the central nervous system

The concept of moderate consumption of ethanol (beverage alcohol) has evolved over time from considering this level of intake to be nonintoxicating and noninjurious, to encompassing levels defined as "statistically" normal in particular populations, and the public health-driven concepts that define moderate drinking as the level corresponding to the lowest overall rate of morbidity or mortality in a population. The various approaches to defining moderate consumption of ethanol provide for a range of intakes that can result in blood ethanol concentrations ranging from 5 to 6 mg/dl, to levels of over 90 mg/dl (i.e., approximately 20 mM). This review summarizes available information regarding the effects of moderate consumption of ethanol on the adult and the developing nervous systems. The metabolism of ethanol in the human is reviewed to allow for proper appreciation of the important variables that interact to influence the level of exposure of the brain to ethanol once ethanol is orally consumed. At the neurochemical level, the moderate consumption of ethanol selectively affects the function of GABA, glutamatergic, serotonergic, dopaminergic, cholinergic, and opioid neuronal systems. Ethanol can affect these systems directly, and/or the interactions between and among these systems become important in the expression of ethanol's actions. The behavioral consequences of ethanol's actions on brain neurochemistry, and the neurochemical effects themselves, are very much dose- and time-related, and the collage of ethanol's actions can change significantly even on the rising and falling phases of the blood ethanol curve. The behavioral effects of moderate ethanol intake can encompass events that the human or other animal can perceive as reinforcing through either positive (e.g., pleasurable, activating) or negative (e.g., anxiolysis, stress reduction) reinforcement mechanisms. Genetic factors and gender play an important role in the metabolism and behavioral actions of ethanol, and doses of ethanol producing pleasurable feelings, activation, and reduction of anxiety in some humans/animals can have aversive, sedative, or no effect in others. Research on the cognitive effects of acute and chronic moderate intake of ethanol is reviewed, and although a number of studies have noted a measurable diminution in neuropsychologic parameters in habitual consumers of moderate amounts of ethanol, others have not found such changes. Recent studies have also noted some positive effects of moderate ethanol consumption on cognitive performance in the aging human. The moderate consumption of ethanol by pregnant women can have significant consequences on the developing nervous system of the fetus. Consumption of ethanol during pregnancy at levels considered to be in the moderate range can generate fetal alcohol effects (behavioral, cognitive anomalies) in the offspring. A number of factors--including gestational period, the periodicity of the mother's drinking, genetic factors, etc.--play important roles in determining the effect of ethanol on the developing central nervous system. A series of recommendations for future research endeavors, at all levels, is included with this review as part of the assessment of the effects of moderate ethanol consumption on the central nervous system.

Changing incidence of central nervous system diseases in the EuroSIDA cohort

A drastic decrease in incidence has been observed for most human immunodeficiency virus (HIV)-related opportunistic manifestations after use of highly active antiretroviral therapy (HAART). We assessed the trend of incidence of central nervous system (CNS) diseases in a prospective multicenter observational study involving 9,803 patients across Europe in the period 1994 to 2002 and analyzed patient and treatment variables associated with these conditions. Overall, 568 patients (5.8%) received a diagnosis of a new CNS disease. Incidence decreased significantly from 5.9 per 100 person-year in 1994 to 0.5 in 2002. Overall, the decrease was 40% per calendar year, and it was similar to that of non-CNS diseases and less evident after year 1998. In multivariable models, low CD4 cell count and high plasma viral load, but not HAART or calendar year, were significantly associated with risk to develop CNS disease, indicating that the effect of HAART was likely mediated by both improved immunological conditions and inhibition of viral replication. In contrast, use of nucleoside reverse transcriptase inhibitors, irrespective of use of protease inhibitors or non-nucleoside reverse transcriptase inhibitors, appeared to protect specifically against acquired immunodeficiency disease syndrome dementia complex, suggesting that, in this condition, therapy might have a direct, additive effect in the CNS.

Circulating microRNAs: a novel class of potential biomarkers for diagnosing and prognosing central nervous system diseases

As a class of important endogenous small noncoding RNAs that regulate gene expression at the posttranscriptional level, microRNAs (miRNAs) play a critical role in many physiological and pathological processes. It is believed that miRNAs contribute to the development, differentiation, and synaptic plasticity of the neurons, and their dysregulation has been linked to a series of diseases. MiRNAs exist in the tissues and as circulating miRNAs in several body fluids, including plasma or serum, cerebrospinal fluid, urine, and saliva. There are significant differences between the circulating miRNA expression profiles of healthy individuals and those of patients. Consequently, circulating miRNAs are likely to become a novel class of noninvasive and sensitive biomarkers. Although little is known about the origin and functions of circulating miRNAs at present, their roles in the clinical diagnosis and prognosis of diseases make them attractive markers, particularly for tumors and cardiovascular diseases. Until now, however, there have been limited data regarding the roles of circulating miRNAs in central nervous system (CNS) diseases. This review focuses on the characteristics of circulating miRNAs and their values as potential biomarkers in CNS diseases, particularly in Alzheimer's disease, Huntington's disease, multiple sclerosis, schizophrenia, and bipolar disorder.

Intravenous immunoglobulin treatment in paraneoplastic neurological syndromes with antineuronal autoantibodies

OBJECTIVE

To evaluate the effect of intravenous high dose human immunoglobulin (IVIg) therapy on the clinical course and autoantibody titres of patients with neurological paraneoplastic syndromes.

METHODS

Twenty two patients with paraneoplastic encephalomyelitis and sensory neuronopathy syndrome associated with anti-Hu antibodies (18) or paraneoplastic cerebellar degeneration (PCD) with anti-Yo antibodies (four), were treated with 1-26 (mean 5.8) cycles of IVIg. The Rankin scale was used to evaluate the response.

RESULTS

The only serious toxicity was one case of haemolytic anaemia. Twenty one patients were evaluable for therapeutic response. One patient, with subacute sensory neuronopathy (SSN), improved for at least 15 months, 10 remained stable (eight with anti-Hu and two with anti-Yo antibodies), and 10 deteriorated (eight with anti-Hu and two with anti-Yo antibodies). In seven of the 10 patients who stabilised, the syndrome had already made a plateau when the treatment was started but three patients (one with anti-Hu and two with anti-Yo antibodies) who had still been progressing stabilised for six, eight, and more than 48 months, including one patient with SSN who achieved stabilisation when the neurological dysfunction was only moderate (Rankin scale = 3). Another patient with SSN and initial stable response worsened when IVIg was reduced and improved when it was increased. No significant predictive factors of outcome could be identified but improvement or stabilisation was more frequent in patients with isolated involvement of the peripheral nervous system (62%) than in patients with evidence of CNS damage (37%) at the onset of treatment. Stabilisation in patients with CNS involvement was only achieved when the neurological dysfunction was already severe (Rankin scale > 3). The titres of autoantibodies did not change significantly.

CONCLUSION

Treatment with IVIg at the doses given in the present protocol was not effective in paraneoplastic CNS syndromes associated with antineuronal antibodies. The role of this regime in the treatment of SSN should be further evaluated.

Detection of influenza virus RNA by reverse transcription-PCR and proinflammatory cytokines in influenza-virus-associated encephalopathy

Eleven children with acute encephalopathy associated with an influenza virus infection were treated during the 1997-1998 influenza season. Reverse transcription-polymerase chain reaction (RT-PCR) assay was used to detect the viral genome in peripheral blood and cerebrospinal fluid (CSF) samples. The results were compared with those of control influenza patients without neurological complications. Viral RNA was detected only in the peripheral blood mononuclear cells of one patient with influenza-virus-associated encephalopathy (1 of 9; 11%) and in the CSF of another patient (1 of 11;9%). RT-PCR was negative in the blood of all the controls, but the percentage of RT-PCR-positive samples in the two groups was not significantly different. Cytokines and soluble cytokine receptors in plasma and CSF were then quantified using an enzyme-linked immunosorbent assay. The CSF concentrations of soluble tumor necrosis factor receptor-1 were elevated in two patients and interleukin-6 (IL-6) was elevated in one patient with influenza-virus-associated encephalopathy. On the other hand, the plasma concentrations of IL-6 were elevated in four of nine patients. The number of encephalopathy patients who had elevated plasma concentrations of IL-6 100 pg/ml was significantly higher than that of controls (P= .01). In conclusion, the infrequent detection of the viral genome in the CSF and blood showed that direct invasion of the virus into the central nervous system was an uncommon event. Proinflammatory cytokines and soluble cytokine receptors may mediate the disease. The high plasma concentration of IL-6 could be an indicator of the progression to encephalopathy.

Central nervous system abnormalities in Lyme neuroborreliosis

Intrathecal production of anti-Borrelia burgdorferi antibody occurs frequently in CNS Lyme, yet reliable diagnosis of neuroborreliosis is still considered difficult and controversial. Therefore, we assessed the utility of this measurement in 103 Lyme patients. Among 15 patients with Lyme meningoradiculitis and 41 controls, diagnostic specificity was 93% and sensitivity 87%. Application of this method permits the identification of a rare B burgdorferi-associated multifocal encephalitis (brain infection) and its differentiation from a milder encephalopathy, or confusional state; the latter may not require CNS bacterial invasion. The encephalitis involves white matter more often than gray; severity varies widely. Of six patients with this antibiotic-responsive encephalitis, five were positive for HLA DQw3(DQw7). We conclude that (1) measurement of intrathecal antibody production is a reliable indicator of CNS infection, (2) North American neuroborreliosis includes the same spectrum of neurologic dysfunction as described in Europe, and (3) HLA typing may be useful in furthering our understanding of severe CNS involvement.

The potential role for arachidonic and docosahexaenoic acids in protection against some central nervous system injuries in preterm infants

The risk of central nervous, visual, and auditory damage increases from 2/1000 live births in the normal birthweight to > 200/1000 as birthweight falls below 1500 g. Such babies are most likely to be born preterm. Advances in infant care have led to increasing numbers of very-low-birthweight, preterm infants surviving to school age with moderate to severe brain damage. Steroids are one of the current treatments, but they cause significant, long-term problems. The evidence reported here suggests an additional approach to protecting the very preterm infant by supporting neurovascular membrane integrity. The complications of preterm, very-low-birthweight babies include bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular hemorrhage, periventricular leukomalacia, and necrotizing enterocolitis, all of which have a vascular component. Arachidonic acid (AA) and DHA are essential, structural, and functional constituents of cell membranes. They are especially required for the growth and function of the brain and vascular systems, which are the primary biofocus of human fetal growth. Molecular dynamics and experimental evidence suggest that DHA could be the ligand for the retinoid X receptor (RXR) in neural tissue. RXR activation is an obligatory step in signaling to the nucleus and in the regulation of gene expression. Very preterm babies are born with minimal fat stores and suboptimal circulating levels of these nutrients. Postnatally, they lose the biomagnification of the proportions of AA and DHA by the placenta for the fetus. No current nutritional management repairs these deficits. The placental biomagnification profile highlights AA rather than DHA. The resultant fetal FA profile closely resembles that of the vascular endothelium and not the brain. Without this nourishment, cell membrane abnormalities would be predicted. We present a scientific rationale for a common pathogenic process in the complications of prematurity.

D18G transthyretin is monomeric, aggregation prone, and not detectable in plasma and cerebrospinal fluid: a prescription for central nervous system amyloidosis?

Over 70 transthyretin (TTR) mutations facilitate amyloidosis in tissues other than the central nervous system (CNS). In contrast, the D18G TTR mutation in individuals of Hungarian descent leads to CNS amyloidosis. D18G forms inclusion bodies in Escherichia coli, unlike the other disease-associated TTR variants overexpressed to date. Denaturation and reconstitution of D18G from inclusion bodies afford a folded monomer that is destabilized by 3.1 kcal/mol relative to an engineered monomeric version of WT TTR. Since TTR tetramer dissociation is typically rate limiting for amyloid formation, the monomeric nature of D18G renders its amyloid formation rate 1000-fold faster than WT. It is perplexing that D18G does not lead to severe early onset systemic amyloidosis, given that it is the most destabilized TTR variant characterized to date, more so than variants exhibiting onset in the second decade. Instead, CNS impairment is observed in the fifth decade as the sole pathological manifestation; however, benign systemic deposition is also observed. Analysis of heterozygote D18G patient's serum and cerebrospinal fluid (CSF) detects only WT TTR, indicating that D18G is either rapidly degraded postsecretion or degraded within the cell prior to secretion, consistent with its inability to form hybrid tetramers with WT TTR. The nondetectable levels of D18G TTR in human plasma explain the absence of an early onset systemic disease. CNS disease may result owing to the sensitivity of the CNS to lower levels of D18G aggregate. Alternatively, or in addition, we speculate that a fraction of D18G made by the choroid plexus can be transiently tetramerized by the locally high thyroxine (T(4)) concentration, chaperoning it out into the CSF where it undergoes dissociation and amyloidogenesis due to the low T(4) CSF concentration. Selected small molecule tetramer stabilizers can transform D18G from a monomeric aggregation-prone state to a nonamyloidogenic tetramer, which may prove to be a useful therapeutic strategy against TTR-associated CNS amyloidosis.

Energetic characteristics of the new transthyretin variant A25T may explain its atypical central nervous system pathology

Transthyretin (TTR) is a tetrameric protein that must misfold to form amyloid fibrils. Misfolding includes rate-limiting tetramer dissociation, followed by fast tertiary structural changes that enable aggregation. Amyloidogenesis of wild-type (WT) TTR causes a late-onset cardiac disease called senile systemic amyloidosis. The aggregation of one of > 80 TTR variants leads to familial amyloidosis encompassing a collection of disorders characterized by peripheral neuropathy and/or cardiomyopathy. Prominent central nervous system (CNS) impairment is rare in TTR amyloidosis. Herein, we identify a new A25T TTR variant in a Japanese patient who presented with CNS amyloidosis at age 42 and peripheral neuropathy at age 44. The A25T variant is the most destabilized and fastest dissociating TTR tetramer published to date, yet, surprising, disease onset is in the fifth decade. Quantification of A25T TTR in the serum of this heterozygote reveals low levels relative to WT, suggesting that protein concentration influences disease phenotype. Another recently characterized TTR CNS variant (D18G TTR) exhibits strictly analogous characteristics, suggesting that instability coupled with low serum concentrations is the signature of CNS pathology and protects against early-onset systemic amyloidosis. The low A25T serum concentration may be explained either by impaired secretion from the liver or by increased clearance, both scenarios consistent with A25T's low kinetic and thermodynamic stability. Liver transplantation is the only known treatment for familial amyloid polyneuropathy. This is a form of gene therapy that removes the variant protein from serum preventing systemic amyloidosis. Unfortunately, the choroid plexus would have to be resected to remove A25T from the CSF-the source of the CNS TTR amyloid. Herein we demonstrate that small-molecule tetramer stabilizers represent an attractive therapeutic strategy to inhibit A25T misfolding and CNS amyloidosis. Specifically, 2-[(3,5-dichlorophenyl)amino]benzoic acid is an excellent inhibitor of A25T TTR amyloidosis in vitro.

Cerebrospinal fluid interleukin-6 in progressive Neuro-Behçet's syndrome

Central nervous system (CNS) involvement in Behçet's disease, usually called neuro-Behçet's syndrome (NB), is one of the most serious complications of the disease. The present study examined cerebrospinal fluid (CSF) interleukin-6 (IL-6) activity in patients with NB to explore its relevance to the progressive CNS disease. Paired CSF and serum specimens were obtained from 11 patients who were diagnosed as having progressive NB based on careful clinical observation and from 11 patients with active Behçet's disease but lacking progressive CNS disease. IL-6 levels in the CSF and sera were determined using IL-6-dependent murine hybridoma MH60.BSF2 cells. All 11 patients with progressive NB showed marked elevation of CSF IL-6 activity [0.18-3.90 U/ml, 1.19 +/- 1.18 (mean +/- SD), normal range, <0.010 U/ml]. In contrast, only 5 of the 11 control patients showed very modest CSF IL-6 activity below 0.10 U/ml, and CSF IL-6 was not detected in the other 6 patients. There was no difference in the serum IL-6 activities of patients with progressive NB and control patients. There was no significant correlation of CSF IL-6 activity with serum IL-6 activity, CSF cell counts, CSF total protein levels, or the CSF/serum albumin quotient. These results indicate that persistent chronic CNS inflammation, as evidenced by the enhanced production of IL-6 within the CNS, plays an important role in the pathogenesis of progressive neuropsychiatric manifestations in Behcet's disease.

Neuro-Coagulopathy: Blood Coagulation Factors in Central Nervous System Diseases

Blood coagulation factors and other proteins, with modulatory effects or modulated by the coagulation cascade have been reported to affect the pathophysiology of the central nervous system (CNS). The protease-activated receptors (PARs) pathway can be considered the central hub of this regulatory network, mainly through thrombin or activated protein C (aPC). These proteins, in fact, showed peculiar properties, being able to interfere with synaptic homeostasis other than coagulation itself. These specific functions modulate neuronal networks, acting both on resident (neurons, astrocytes, and microglia) as well as circulating immune system cells and the extracellular matrix. The pleiotropy of these effects is produced through different receptors, expressed in various cell types, in a dose- and time-dependent pattern. We reviewed how these pathways may be involved in neurodegenerative diseases (amyotrophic lateral sclerosis, Alzheimer's and Parkinson's diseases), multiple sclerosis, ischemic stroke and post-ischemic epilepsy, CNS cancer, addiction, and mental health. These data open up a new path for the potential therapeutic use of the agonist/antagonist of these proteins in the management of several central nervous system diseases.

The utility of basal serum LH in prediction of central precocious puberty in girls

OBJECTIVE

The mainstay of distinction between prepubertal girls and girls who are suspected of having central precocious puberty (CPP) is based on gonadotropin measurements after a GnRH stimulation test to evaluate hypothalamic-pituitary-gonadal axis maturity. The objective of this study was to determine whether a single basal gonadotropin measurement carries a useful predictive value in verifying or refuting the diagnosis of CPP.

DESIGN AND METHODS

Basal serum LH and FSH were measured by a chemiluminescent immunometric assay in a cohort of girls who had been evaluated for CPP before and after GnRH stimulation test. Peak LH levels higher than 5 IU/l were considered a pubertal response.

RESULTS

Eighty girls with suspected breast development before 8 years of age were enrolled to the study, out of whom 42 had CPP. Low basal serum LH (≤0.1 IU/l) was sufficient to rule out the diagnosis of CPP in 94.7% of the 38 prepubertal girls; the sensitivity of basal LH levels for this purpose was only 64%. The basal FSH and the basal LH to FSH ratio achieved less efficient predictive value with 76 and 71% sensitivity and 73 and 86% specificity respectively.

CONCLUSION

A single basal LH measurement may be adequate to confirm but not to refute the presence of CPP in most of the girls who are evaluated for early pubertal signs.

Behçet's disease. Relation of serum C-reactive protein and erythrocyte sedimentation rates to disease activity

In a prospective study of 150 patients with Behçet's disease, significant associations were shown between CRP positivity and the presence of erythema nodosum (p less than 0.02) and acute thrombophlebitis (p less than 0.05) and between ESR and erythema nodosum (p less than 0.01), acute thrombophlebitis (p less than 0.001), and acute arthritis (p less than 0.01). Mucocutaneous, ocular, or central nervous system activities did not show significant associations with these indices of inflammation. In 50 patients in whom quantitative CRP determinations were performed, clinical disease activity was accompanied by slight to moderate increases in CRP and ESR.

Serum and cerebrospinal fluid antibodies to Nogo-A in patients with multiple sclerosis and acute neurological disorders

Nogo-A is a protein associated with central nervous system (CNS) myelin thought to impair regenerative responses and to suppress sprouting and plastic changes of synaptic terminals. In this study, we report that serum IgM autoantibodies to the recombinant large N-terminal inhibitory domain of Nogo-A are a frequent finding in multiple sclerosis (MS) and acute inflammatory (IND) and non-inflammatory neurological diseases (OND), but not in neurodegenerative diseases (ND), systemic inflammatory disease and healthy controls. Furthermore, we demonstrate intrathecal production of anti-Nogo-A antibodies measured by increased IgG indices. Intrathecal anti-Nogo antibodies were significantly more frequent in patients with relapsing-remitting as compared to chronic progressive (CP) MS. We also found a highly significant negative correlation of these antibody responses with age indicating that they are more frequent in younger patients. We finally demonstrate that human anti-Nogo-A antibodies recognize native Nogo-A in brain extracts, oligodendrocytes and cells expressing human Nogo-A.

Flow cytometry and the study of central nervous disease in patients with acute leukaemia

Central nervous system (CNS) leukaemia is still a matter of debate and new technologies are required to improve the classic morphological definition. One hundred and sixty-eight cerebrospinal fluid (CSF) samples from 31 patients with acute leukaemia were analysed by flow cytometry and conventional cytology. Concordant positive and negative findings were found in 158 samples but 10 produced discrepant results. Cytology seemed to offer more precise information in one CSF sample and flow cytometric accuracy could be demonstrated in five samples. We conclude that flow cytometry is of great help in confirming CNS leukaemia and eliminating other conditions. Therefore, leukaemic patients can benefit from double cytological and flow cytometric CSF studies.

Prolactin and interleukin-6 in neuropsychiatric lupus erythematosus

We investigated the levels of prolactin (PRL) and interleukin-6 (IL-6) in the cerebrospinal fluid (CSF) and serum of systemic lupus erythematosus patients with central nervous system involvement (CNS-SLE), and examined whether PRL and IL-6 have a relationship. Serum and CSF PRL and IL-6 were measured in the following groups of patients and controls: group I: seven patients with CNS-SLE; group II: three SLE patients without CNS involvement (non CNS-SLE); group III: 10 patients with neurocysticercosis; and group IV: six healthy women. The patients were clinically assessed. CSF PRL and IL-6 were elevated in group I (CNS-SLE) in comparison with all other groups (p<0.001). In addition, four of seven patients had higher levels of IL-6 and PRL in CSF than in serum. A positive correlation between PRL and IL-6 in CSF of SLE was observed (r=0.88, p<0.001). The mean serum PRL concentrations were not significantly different in all groups, but high levels of IL-6 were found in the serum of group I in comparison with groups II and IV (p<0.001). The serum levels of group III were not different from those of group I. These results demonstrate the presence of intrathecal synthesis and elevations of CSF PRL and IL-6 in active CNS-SLE involvement and indicate that measurements of CSF PRL and IL-6 may be useful in the evaluation of neuropsychiatric lupus erythematosus.

Thyroid Hormone Analogues: An Update

The development of thyroid hormone (TH) analogues was prompted by the attempt to exploit the effects of TH on lipid metabolism, avoiding cardiac thyrotoxicosis. Analysis of the relative distribution of the α and β subtypes of nuclear TH receptors (TRα and TRβ) showed that TRα and TRβ are responsible for cardiac and metabolic responses, respectively. Therefore, analogues with TRβ selectivity were developed, and four different compounds have been used in clinical trials: GC-1 (sobetirome), KB-2115 (eprotirome), MB07344/VK2809, and MGL-3196 (resmetirom). Each of these compounds was able to reduce low-density lipoprotein cholesterol, but a phase 3 trial with eprotirome was interrupted because of a significant increase in liver enzymes and the contemporary report of cartilage side effects in animals. As a consequence, the other projects were terminated as well. However, in recent years, TRβ agonists have raised new interest for the treatment of nonalcoholic fatty liver disease (NAFLD). After obtaining excellent results in experimental models, clinical trials have been started with MGL-3196 and VK2809, and the initial reports are encouraging. Sobetirome turned out to be effective also in experimental models of demyelinating disease. Aside TRβ agonists, TH analogues include some TH metabolites that are biologically active on their own, and their synthetic analogues. 3,5,3'-triiodothyroacetic acid has already found clinical use in the treatment of some cases of TH resistance due to TRβ mutations, and interesting results have recently been reported in patients with the Allan-Herndon-Dudley syndrome, a rare disease caused by mutations in the TH transporter MCT8. 3,5-diiodothyronine (T2) has been used with success in rat models of dyslipidemia and NAFLD, but the outcome of a clinical trial with a synthetic T2 analogue was disappointing. 3-iodothyronamine (T1AM) is the last entry in the group of active TH metabolites. Promising results have been obtained in animal models of neurological injury induced by β-amyloid or by convulsive agents, but no clinical data are available so far.

The concentration of prealbumin in cerebrospinal fluid (CSF), indicator of CSF circulation disorders

Prealbumin, was determined in serum, lumbar and ventricular cerebrospinal fluid (CSF) and compared with albumin and IgG. The measured concentrations of prealbumin in the CSF indicate that there are two sources of prealbumin: a minor fraction enters the CSF via the blood-cerebrospinal fluid (B-CSF) barrier like albumin, and the major fraction enters the CSF at the ventricles, probably during production of the CSF in the ventricles. The two fractions can be calculated from the CSF concentration of prealbumin, serum prealbumin and the concentration gradient (serum/CSF) of albumin. The B-CSF barrier-independent prealbumin can be used as an indicator of CSF circulation. This was proved by the investigation of several special cases.

Early differential diagnosis of multiple sclerosis using a new oligoclonal band test

BACKGROUND

Intrathecal IgG synthesis (ITGS), in conjunction with magnetic resonance imaging, can help in the early diagnosis of multiple sclerosis (MS). Recently, we developed a new oligoclonal IgG band (OCGB) test for ITGS detection that is more sensitive and easier to interpret than previously described methods.

OBJECTIVE

To assess the accuracy of a new OCGB detection test in the diagnosis of MS.

DESIGN

Prospective observational study.

SETTING

A hospital neurology department. Patients A total of 385 patients with various neurologic disorders.

MAIN OUTCOME MEASURES

The sensitivity and specificity of the OCGB detection test for MS diagnosis.

RESULTS

Intrathecal IgG synthesis was found in 127 patients with MS (96.2%), 18 (35.3%) with central nervous system infections, and 1 with motor neuron disease. Two patterns reflected ITGS. One pattern, showing OCGBs restricted to cerebrospinal fluid, was predominantly found in MS. The other pattern, with OCGBs in serum and additional bands in cerebrospinal fluid, was mostly found in central nervous system infections. No patients with other inflammatory neurologic diseases showed ITGS. These patients frequently displayed a mirror pattern, with identical bands in serum and cerebrospinal fluid. Considering all patients, the sensitivity for the diagnosis of MS was 96.2%, and the specificity was 92.5%. Excluding infections, which usually do not present a differential diagnosis problem with MS, the sensitivity was still 96.2%, and the specificity increased to 99.5%.

CONCLUSION

The accuracy of this OCGB method reinforces the value of cerebrospinal fluid studies in the early differential diagnosis of MS.

Occupational exposure to lead and neuropsychological dysfunction

OBJECTIVE

To evaluate the neuropsychological effects of current low level and previous higher levels of exposure to lead and evaluate the relation between effects of lead and bone lead.

METHODS

A neuropsychological test battery was given to 54 storage battery workers with well documented long term exposure to lead. The effect was studied in two subgroups: those whose blood lead had never exceeded 2.4 mmol/l (the low BPbmax group, n = 26), and those with higher exposure about 10 years earlier (the high BPbmax group, n = 28). In both groups, the recent exposure had been low. Correlations between the test scores and the indices of both long term and recent exposure--including the content of lead in the tibial and calcaneal bone--and covariance analyses were used to assess the exposure-effect relation. Age, sex, and education were controlled in these analyses.

RESULTS

Analyses within the low BPbmax group showed a decrement in visuospatial and visuomotor function (block design, memory for design, Santa Ana dexterity), attention (digit symbol, digit span), and verbal comprehension (similarities) associated with exposure to lead and also an increased reporting of subjective symptoms. The performance of the high BPbmax group was worse than that of the low BPbmax group for digit symbol, memory for design, and embedded figures, but there was no reporting of symptoms related to exposure, probably due to selection in this group. No relation was found between the output variables and the tibial lead concentration. The calcaneal lead concentrations were related to the symptoms in the low BPbmax group.

CONCLUSIONS

Neuropsychological decrements found in subjects with high past and low present exposure indicate that blood lead concentrations rising to 2.5-4.9 mmol/l cause a risk of long lasting or even permanent impairment of central nervous system function. Milder and narrower effects are associated with lower exposures; their reversibility and time course remain to be investigated. History of blood lead gives a more accurate prediction of the neuropsychological effects of lead than do measurements of bone lead.

Peripheral neuroactive steroids may be as good as the steroids in the cerebrospinal fluid for the diagnostics of CNS disturbances

To compare the predictivity of the neuroactive steroids in the cerebrospinal fluid and peripheral blood for the diagnostics of CNS disturbances, eighteen unconjugated steroids were quantified in the cerebrospinal fluid (CSF) from the 3rd ventricle and 18 unconjugated steroids and 7 steroid polar conjugates were measured in the serum using GC-MS and RIA. Eight postmenopausal women (56-78 years of age) and 7 men (22-88 years of age) with hydrocephalus were enrolled in the study. The sensitivity of the method ranged from low femtogram to low picogram levels depending on the steroid fragmentation pattern. Using multivariate regression, a model for simultaneous prediction of the CSF steroids from the serum steroids was completed. Then, the penetrability of the individual steroids across the blood-brain-barrier was evaluated and the sources of various brain steroids were estimated. Our data show that a part of the steroids may be synthesized de novo in the CNS. However, substantial part of the steroid metabolites may be synthesized in the CNS from the steroid precursors or directly transported from the periphery. The CNS in situ synthesis and transport from periphery might be complementary in some cases, i.e. brain synthesis might provide minimum level of steroids, which are indispensable for the CNS functions.

Human herpesvirus 6 infects the central nervous system of multiple sclerosis patients in the early stages of the disease

The presence and the replicative state of human herpesvirus 6 (HHV-6) were evaluated in clinical samples from multiple sclerosis (MS) patients at the first time of MS diagnosis. HHV-6 variant B was present in peripheral blood mononuclear cells of 5/32 (15%) patients, but persisted with a latent infection. Viral sequences were present also in cerebrospinal fluid (CSF), both free in the liquid (7/32, 22%) and latent in the cellular fraction (3/32, 9%), as shown by analysis of viral transcription. In these cases, variant A was detected. HHV-6 DNA sequences present in the CSF were associated to mature viral particles. In fact, in vitro infectious assays of CSF showed the presence of replication-competent virions. These results show that about 20% of MS patients have active foci of HHV-6 variant A infection in the early stages of the disease and suggest that viral replication takes place within the central nervous system.

Low prevalence of TT virus in the cerebrospinal fluid of viremic patients with central nervous system disorders

TT virus (TTV) is a widespread infectious agent of humans identified in 1998. In infected individuals, TTV induces persistent viremia but its life cycle and pathogenic potential are still poorly understood. In the present study, the presence of TTV DNA in 32 consecutive paired serum and cerebrospinal fluid (CSF) samples from patients with neurological (mainly multiple sclerosis) disorders was investigated by means of a sensitive quantitative real-time PCR assay. Of the 24 patients who were found to carry TTV DNA in serum, 3 also had detectable TTV DNA in their CSF. Two TTV positive CSF samples had markers indicative of blood contamination or a disrupted blood-brain barrier and contained considerably lower TTV loads as compared with the corresponding serum samples, thus suggesting that the virus they contained was of plasma origin. These findings indicated that in general TTV does not permeate effectively an intact blood-brain barrier. Furthermore, the CNS does not represent a common site of TTV replication and persistence. However, at least one exception was observed: the third TTV positive CSF sample (obtained from a patient with subacute dementia of unknown origin) showed no markers suggestive of disrupted blood-brain barrier or blood contamination and had a TTV DNA concentration similar to that found in the patient's serum. In addition, the TTV isolates detected in the two body fluids were distinct genetically. The detection of TTV DNA in CSF is of considerable interest but the clinical significance remains unknown.