Transverse relaxation of cerebrospinal fluid depends on glucose concentration

PURPOSE

To evaluate the biophysical processes that generate specific T₂ values and their relationship to specific cerebrospinal fluid (CSF) content.

MATERIALS AND METHODS

CSF T_2s were measured ex vivo (14.1T) from isolated CSF collected from human, rat and non-human primate. CSF T_2s were also measured in vivo at different field strength in human (3 and 7T) and rodent (1, 4.7, 9,4 and 11.7T) using different pulse sequences. Then, relaxivities of CSF constituents were measured, in vitro, to determine the major molecule responsible for shortening CSF T₂ (2s) compared to saline T₂ (3s). The impact of this major molecule on CSF T₂ was then validated in rodent, in vivo, by the simultaneous measurement of the major molecule concentration and CSF T₂.

RESULTS

Ex vivo CSF T₂ was about 2.0s at 14.1T for all species. In vivo human CSF T₂ approached ex vivo values at 3T (2.0s) but was significantly shorter at 7T (0.9s). In vivo rodent CSF T₂ decreased with increasing magnetic field and T₂ values similar to the in vitro ones were reached at 1T (1.6s). Glucose had the largest contribution of shortening CSF T₂in vitro. This result was validated in rodent in vivo, showing that an acute change in CSF glucose by infusion of glucose into the blood, can be monitored via changes in CSF T₂ values.

CONCLUSION

This study opens the possibility of monitoring glucose regulation of CSF at the resolution of MRI by quantitating T₂.

Oligoclonal bands in multiple sclerosis reactive against two herpesviruses and association with magnetic resonance imaging findings

BACKGROUND

Two human herpesviruses, human herpesvirus 6 (HHV-6), and Epstein-Barr virus (EBV), have been repeatedly linked to multiple sclerosis (MS).

OBJECTIVE

The aim of this study was to investigate HHV-6 and EBV reactive oligoclonal bands (OCBs), and viral DNA in the intrathecal compartment in MS.

METHODS

The reactivity of OCBs in cerebrospinal fluid (CSF) for EBV and HHV-6 antigens and stability of virus reactive OCBs over time were studied in a well-characterized MS patient cohort. Associations between virus reactive OCBs and viral DNA in CSF (and any clinical and/or radiological findings) were investigated.

RESULTS

Of patients with MS, 38% had OCBs reactive to either one of the viruses studied, compared to none in the patients with other inflammatory neurological diseases (p=0.005). The banding pattern of virus reactive OCBs remained the same over time. Furthermore, MS patients with viral DNA in CSF had more contrast enhancing lesions (CELs).

CONCLUSION

The stable presence of herpesvirus reactive OCBs in CSF further strengthens the association of MS with these viruses. The finding that herpesviruses might be linked to the appearance of active lesions warrants investigation of new therapeutic strategies to treat these viruses in MS.

Fabrication and evaluation of SixNy coatings for total joint replacements

Wear particles from the bearing surfaces of joint implants are one of the main limiting factors for total implant longevity. Si(3)N(4) is a potential wear resistant alternative for total joint replacements. In this study, Si(x)N(y)-coatings were deposited on cobalt chromium-discs and Si-wafers by a physical vapour deposition process. The tribological properties, as well as surface appearance, chemical composition, phase composition, structure and hardness of these coatings were analysed. The coatings were found to be amorphous or nanocrystalline, with a hardness and coefficient of friction against Si(3)N(4) similar to that found for bulk Si(3)N(4). The low wear rate of the coatings indicates that they have a potential as bearing surfaces of joint replacements. The adhesion to the substrates remains to be improved.

Developments in MS over the Past 17 Years the MS Forum and The International MS Journal

When The International MS Journal (IMSJ) first appeared in 1994 multiple sclerosis (MS) was an under-recognized disease of little interest therapeutically. Its frequency was not great enough to interest the major pharmaceutical companies, its cause was unknown and evidence of any major therapeutic effect was lacking.

Epstein-Barr Virus and MS:Causality or Association?

The search for the aetiology of multiple sclerosis (MS) has led to many theories over the years. It has become clear, however, that MS is complex and multifactorial, involving many interlacing mechanisms, many of which appear to be playing a role in the causation and evolution of the disease. In the large part for epidemiological reasons, an infectious aetiology has always been a prime suspect in this search. Although many agents have been examined over the years, the Epstein-Barr virus (EBV) has re-emerged as a candidate pathogen, based to a large degree on sero-epidemiological evidence, and on the knowledge of the effects this virus is capable of producing in other situations.

Non-Linear Optical Polymers for Active Optical Devices

Second order non-linear optical (NLO) polymers have been the focus of intense research effort in recent years [1]. This effort is justified by the potential value of these materials in a range of attractive optical signal processing applications with lower device costs and enhanced device performance.

Alloreactivity but failure to reject human islet transplants by humanized Balb/c/Rag2gc mice

A human islet transplant can cure patients with type 1 diabetes. A drawback of islet transplantation is the life-long immunosuppressive medication, often associated with severe side effects. Moreover, in spite of the immunosuppressive therapy, islets are lost in the majority of transplanted patients over time. An improved small animal model for studies on human islet allograft rejection mechanisms and the development of new measures for its prevention is clearly warranted. Here, we evaluated the potential of Balb/cRag2(-/-)gammac(-/-) mice carrying a human-like immune system (so-called humanized mice) as a tool for studies on the rejection of transplanted human islets. Human T cells from Balb/cRag2(-/-)gammac(-/-) mice, which as neonates had been transplanted with CD34(+) human cord blood haematopoietic stem cells (HIS mice), proliferated in response to allogeneic human dendritic cells, but failed to reject a human islet allograft transplanted to the renal subcapsular space as assessed by immunohistochemistry and analysis of human serum C-peptide levels. Histological analysis revealed that few if any T cells had migrated to the grafted tissue. These observations question the usefulness of the HIS mouse model for studies on human islet allograft rejection mechanisms and highlight the need for further improvements.

The target cell response to cytokines governs the autoreactive T cell repertoire in the pancreas of NOD mice

AIMS/HYPOTHESIS

The pancreatic beta cell response to cytokines is crucial for the development of type 1 diabetes in the NOD mouse. For example, beta cell production of suppressor of cytokine signalling-1 (SOCS-1) protects against diabetes. This finding and other recent studies indicated that cytokine-stressed beta cells might contribute to disease progression by affecting the pancreatic lymphocyte infiltrate. The aim of this study was to provide insight into how the beta cell influences the pancreas-infiltrating T cell repertoire.

METHODS

Lymphocytes isolated from Socs1-transgenic (tg) and non-tg NOD mice were analysed by flow cytometry. mRNA and protein levels in pancreatic islets were measured by real-time PCR and immunofluorescence analysis, respectively.

RESULTS

The percentages of regulatory T cells, total counts and ratios between infiltrating CD8+ and CD4+ T cells, and the expression of killer cell lectin-like receptor subfamily K, member 1 (NKG2D) on CD8+ T cells did not differ in pancreases from prediabetic Socs1-tg and non-tg NOD mice. However, a striking difference in the percentages of CD8+ T cells specific for glucose 6-phosphatase catalytic subunit-related protein 206-214 was found, showing that SOCS-1 prevents the accumulation of high percentages of self-reactive CD8+ T cells in the pancreas. It was also found that protection from diabetes in Socs1-tg NOD mice correlated with a reduced expression of Cxcl10 mRNA in IFN-gamma treated islets.

CONCLUSIONS/INTERPRETATION

This study highlights an important role for the beta cell in the local regulation of the diabetogenic process. By responding to the pro-inflammatory pancreas milieu it strongly influences the islet-reactive T cell repertoire in the pancreas.

Total body potassium, fat and water during total parenteral nutrition in Crohn's disease

The body composition was studied by measurement of body weight (BW) and total body potassium (TBK), fat and water in 13 patients with Crohn's disease (CD), who were given altogether 18 courses of total parenteral nutrition (TPN) with nil by mouth each lasting at least 3 weeks. At the start of TPN, one group of steroid-free patients displayed intracellular potassium depletion, as reflected by the ratio TBK/lean body mass (LBM) (group 1). Another group of steroid-free patients showed no depletion of intracellular potassium (group 2). The patients given prednisolone all showed intracellular potassium depletion and were assigned to a separate group (group 3). During the initial 19-44 days of TPN, TBK, LBM and BW increased in group 1. All patients with intracellular potassium depletion (groups 1 + 3) showed an increase in TBK and TBK/LBM during the initial 19-51 days of TPN. For steroid-free patients (groups 1 + 2) there were linear relationships between the rate of energy supply per kg LBM and the 24 h change in BW during the third and fourth weeks of TPN (r = 0.79) and between the 24 h change in BW and LBM during the first 19-44 days of TPN (r = 0.59). A steady state in BW was found on administering 53 kcal/kg LBM/24 h. It is concluded that CD patients with intracellular potassium depletion are likely to be improved in terms of TBK and TBK/LBM by at least 3 weeks of TPN as given in the present study. Steroid-free CD patients with intracellular potassium depletion are, moreover, likely to show an improvement in LBM by at least 3 weeks of TPN, and an increase in their BW during the initial 3-6 weeks of TPN will probably reflect an increase in LBM. The pre-TPN TBK/LBM ratio may be a predictor of the repletion rate of the LBM compartment during TPN of steroid-free wasted CD patients.

Differentiation of HAM/TSP from patients with multiple sclerosis infected with HTLV-I

OBJECTIVE

To better differentiate patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) from patients with multiple sclerosis (MS) who are HTLV-I seropositive, we compared the HTLV-I antibodies and HTLV-I proviral DNA loads in CSF and peripheral blood mononuclear cells (PBMC).

METHODS

Intrathecal synthesis of HTLV-I antibodies and HTLV-I proviral DNA loads in CSF and PBMC were measured and compared in 39 Brazilian patients: 17 HAM/TSP and 22 HTLV-I-seropositive non-HAM/TSP (7 with other neurologic diseases, 11 asymptomatic carriers, and 4 HTLV-I-seropositive patients with an MS-like phenotype). In addition, we followed immunologic and virologic markers in comparison to the clinical course (by Kurtzke Expanded Disability Status Scale) of seven patients (five with HAM/TSP and two with an MS-like phenotype) for a mean period of 16 (SD +/- 5) months.

RESULTS

The proviral load in CSF and PBMC was higher in HAM/TSP than in non-HAM/TSP patients, except in the two HTLV-I-seropositive patients with an MS-like phenotype that also fulfilled the criteria for HAM/TSP. Higher HTLV-I proviral DNA load in CSF was associated with the higher proviral DNA load in PBMC and lower intrathecal synthesis of HTLV-I antibodies. These laboratory findings remained stable during follow-up.

CONCLUSION

The high proviral load in peripheral blood mononuclear cells or in CSF or both may be a good marker of human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and can differentiate patients with HAM/TSP from patients with multiple sclerosis infected with HTLV-I.

Brain volume measurements in patients with human T-cell lymphotropic virus-1–associated tropical spastic paraparesis

Human T-cell lymphotropic virus (HTLV)-1 is associated with a chronic progressive neurologic disease known as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) that affects 0.2% to 3% of HTLV-1-infected people. The authors aimed at exploring, in vivo, whether brain volume reduction occurs in patients with HAM/TSP through the use of magnetic resonance imaging (MRI). T1 pre/postcontrast spin echo-weighted images (WIs) and T2WIs of the brain were obtained in 19 HAM/TSP patients and 14 age-and sex-matched healthy volunteers. Both patients and healthy individuals were imaged at a 1.5-Tesla magnet by employing a conventional head coil. Focal T1 and T2 abnormalities were calculated and two measurements of brain parenchyma fraction (BPF) were obtained by using SIENAx (Structural Image Evaluation,using Normalisation, of Atrophy; University of Oxford, Oxford, UK) and MIPAV (Medical Image Processing, Analysis, and Visualization; National Institutes of Health, Bethesda, USA) from T1WIs. No significant differences in BPF were found between patients and healthy subjects when using either SIENAx or MIPAV. Analysis of individual patients detected that BPF was lower by 1 standard deviation (SD) relative to patients' average BPF in one patient. The authors conclude that reductions in BPF do not occur frequently in patients with HAM/TSP. However, the authors believe that one individual case of significant brain atrophy raises the question as to whether atrophy selectively targets the spinal cord of HAM/TSP patients or may involve the brain as well. A larger patient population analyzing regional brain volume changes could be helpful in determining whether brain atrophy is a marker of disease in patients with HAM/TSP.

Co-purification of soluble membrane cofactor protein (CD46) and human herpesvirus 6 variant A genome in serum from multiple sclerosis patients

The association of human herpesvirus 6 (HHV-6) and multiple sclerosis (MS) has been supported by several immunological and molecular studies. Recently, membrane cofactor protein (CD46) has been identified as the cellular receptor for the A and B variants of HHV-6. Elevated levels of soluble CD46 (sCD46) have been reported in the serum and CSF of MS patients. The aim of this study was to investigate a possible correlation between elevated levels of soluble CD46 and the presence of serum HHV-6 DNA in MS patients. An immunoaffinity column comprised of immobilized monoclonal antibodies to CD46 was developed to isolate sCD46 from cell free body fluids of MS patients and controls. After immunoaffinity purification, DNA was extracted from anti-CD46 column eluates and subjected to PCR amplification. Of the 42 MS samples tested, 4 serum samples were HHV-6 positive, 3 of which were typed as HHV-6A. The co-purification of sCD46 and HHV-6 DNA from MS sera indicates that HHV-6 is tightly connected to its receptor, CD46, in the serum of MS patients.

Discrete serum protein signatures discriminate between human retrovirus-associated hematologic and neurologic disease

The human T-cell leukemia virus type I (HTLV-I) is the causative agent for adult T-cell leukemia (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Approximately 5% of infected individuals will develop either disease and currently there are no diagnostic tools for early detection or accurate assessment of disease state. We have employed high-throughput expression profiling of serum proteins using mass spectrometry to identify protein expression patterns that can discern between disease states of HTLV-I-infected individuals. Our study group consisted of 42 ATL, 50 HAM/TSP, and 38 normal controls. Spectral peaks corresponding to peptide ions were generated from MS-TOF data. We applied Classification and Regression Tree analysis to build a decision algorithm, which achieved 77% correct classification rate across the three groups. A second cohort of 10 ATL, 10 HAM and 10 control samples was used to validate this result. Linear discriminate analysis was performed to verify and visualize class separation. Affinity and sizing chromatography coupled with tandem mass spectrometry was used to identify three peaks specifically overexpressed in ATL: an 11.7 kDa fragment of alpha trypsin inhibitor, and two contiguous fragments (19.9 and 11.9 kDa) of haproglobin-2. To the best of our knowledge, this is the first application of protein profiling to distinguish between two disease states resulting from a single infectious agent.

Primary sepsis in a university hospital in northern Sweden: a retrospective study

BACKGROUND

Severe sepsis and septic shock are associated with high mortality rates. Data on sepsis outcome from Scandinavian countries are sparse. The aim of this study was to examine the length of stay (LOS) in the ICU, ICU mortality and costs of care for adult patients with primary sepsis in a university hospital in northern Sweden.

METHODS

We performed a retrospective data analysis of records of 92 patients admitted over a 3-year period, under the diagnosis of sepsis or urosepsis. Demographic data, admission category, APACHE II score, aetiology and severity of sepsis, ICU LOS, mortality and TISS were analyzed.

RESULTS

Eighty-one adult patients were identified by standard definitions as suffering from sepsis. The median ICU length of stay was 4.2 days, 6 days for survivors and 2.1 days for non-survivors. Thirteen out of 20 deaths occurred within the first 3 days after admission. Overall ICU mortality rate was 24.7% while the ICU mortality for patients with septic shock was 57.7%. The mean costs of care for patients with sepsis were 3139 Euros day(-1) and the cost of care per patient surviving sepsis was 38,494 Euros.

CONCLUSION

The incidence of primary sepsis in our ICU was low. Previous reports on high mortality in association with severe sepsis and septic shock are valid also at our hospital. The ICU-LOS was shorter than previously reported, while our costs of care were in the same range as stated by others. This retrospective analysis is valid for interpretation of the applicability of currently available sepsis therapies.

Detection of human herpesvirus-6 in mesial temporal lobe epilepsy surgical brain resections

BACKGROUND

Human herpesvirus-6 (HHV-6), a ubiquitous beta-herpesvirus, is the causative agent of roseola infantum and has been associated with a number of neurologic disorders including seizures, encephalitis/meningitis, and multiple sclerosis. Although the role of HHV-6 in human CNS disease remains to be fully defined, a number of studies have suggested that the CNS can be a site for persistent HHV-6 infection.

OBJECTIVE

To characterize the extent and distribution of HHV-6 in human glial cells from surgical brain resections of patients with mesial temporal lobe epilepsy (MTLE).

METHOD

Brain samples from eight patients with MTLE and seven patients with neocortical epilepsy (NE) undergoing surgical resection were quantitatively analyzed for the presence of HHV-6 DNA using a virus-specific real-time PCR assay. HHV-6 expression was also characterized by western blot analysis and in situ immunohistochemistry (IHC). In addition, HHV-6-reactive cells were analyzed for expression of glial fibrillary acidic protein (GFAP) by double immunofluorescence.

RESULTS

DNA obtained from four of eight patients with MTLE had significantly elevated levels of HHV-6 as quantified by real-time PCR. HHV-6 was not amplified in any of the seven patients with NE undergoing surgery. The highest levels of HHV-6 were demonstrated in hippocampal sections (up to 23,079 copies/10(6) cells) and subtyped as HHV-6B. Expression of HHV-6 was confirmed by western blot analysis and IHC. HHV-6 was co-localized to GFAP-positive cells that morphologically appeared to be astrocytes.

CONCLUSIONS

HHV-6B is present in brain specimens from a subset of patients with MTLE and localized to astrocytes in the absence of inflammation. The amplification of HHV-6 from hippocampal and temporal lobe astrocytes of MTLE warrants further investigation into the possible role of HHV-6 in the development of MTLE.