Hypokalaemic paralysis precipitated by distal renal tubular acidosis secondary to Sjögren's syndrome.

A 43-year-old woman presented with a sudden onset of hypokalaemic paralysis requiring intubation and ventilatory support. Subsequent biochemical and clinical assessments established a diagnosis of distal renal tubular acidosis (RTA) in association with underlying Sjögren's syndrome as the aetiology of her profound hypokalaemia. Distal RTA is rare, but Sjögren's syndrome is one of the more common causes in adults and should be considered in the differential diagnosis of patients who present with hypokalaemic muscular paralysis.

Polymorphisms in the interleukin-4 and IL-4 receptor genes and multiple sclerosis: a study in Spanish-Basque, Northern Irish and Belgian populations.

Cytokine gene polymorphisms are known to influence susceptibility and disease course of many autoimmune diseases. Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system white matter characterized by inflammation, demyelination and axonal damage. We analysed both the well-known intronic variable number of tandem repeat (VNTR) and +33 C/T single-nucleotide polymorphisms (SNP) in the IL-4 gene, as well as the functional Q551R SNP in the IL4-R gene in a cohort of three distinct populations comprising sporadic cases and controls from the northern Spanish Basque Country and Northern Ireland, as well as family trios from Belgium. The IL-4 +33 TT genotype was decreased in primary progressive (PP) versus relapsing-remitting (RR) patients in the Northern Irish population (OR = 0.14; 95% CI = 0.018-1.09). Two-marker haplotype distribution of the VNTR and +33 C/T SNP in PP patients differed from that seen in RR patients in Northern Ireland (P = 0.03). The R allele of the Q551R SNP was significantly under-transmitted in the Belgian trio families (P = 0.003), although this effect was not seen in the Northern Irish and Basque data sets. We did not identify IL-4-IL4-R gene-gene interaction in determining susceptibility or clinical parameters of MS. Disease or genetic heterogeneity or both may be responsible for the observed lack of reproduction in different populations. Our data reinforce recent findings for a role of IL4-R in susceptibility to MS.

Water diffusion is elevated in widespread regions of normal-appearing white matter in multiple sclerosis and correlates with diffusion in focal lesions.

Pathological changes in the normal-appearing white matter in multiple sclerosis are well recognised, but their relationship to pathology in focal lesions is not well understood. Magnetic resonance diffusion imaging is sensitive to abnormalities in the integrity, size and geometry of water spaces in brain tissue. This study investigated the anatomical distribution of normal-appearing white matter diffusion abnormalities and their relationship to diffusion in focal lesions in multiple sclerosis (MS). The average apparent diffusion coefficient (ADCav) was measured by three-axis echoplanar diffusion imaging in normal-appearing white matter regions and lesions throughout the brain in 40 patients, and in white matter in 14 matched controls. The correlation between the ADCav in normal-appearing white matter and lesions was determined. In controls and patients, diffusion was highest in the corpus callosum. Patients had a higher mean ADCav than controls in widespread regions including the corpus callosum, cerebellar, temporal and occipital normal-appearing white matter. Mean normal-appearing white matter ADCav correlated strongly with mean lesion ADCav (r = 0.67, P < 0.001). This study demonstrates that water diffusion is elevated in widespread areas of normal-appearing white matter in MS, and is correlated with diffusion in lesions. These findings suggest that the pathogenetic mechanisms causing tissue damage in lesions and normal-appearing white matter are at least partly linked.

The pathogenesis of lesions and normal-appearing white matter changes in multiple sclerosis: a serial diffusion MRI study.

The idea that the initiating event in the formation of all new multiple sclerosis lesions is a focal blood-brain barrier (BBB) leakage associated with perivascular inflammation has been challenged recently by the observation of subtle abnormalities in some quantitative magnetic resonance (MR) parameters (including the magnetization transfer ratio) prior to lesion enhancement. MR diffusion imaging can non-invasively quantify the average apparent diffusion coefficient (ADC(av)), a measure of water molecule random motion that is sensitive to pathological change in multiple sclerosis lesions and to abnormalities in the normal-appearing white matter (NAWM). We therefore used MR diffusion imaging to investigate the dynamic evolution of water diffusion measurements in new enhancing multiple sclerosis lesions, in the NAWM from which they arise, and in anatomically matched contralateral NAWM regions from which no visible lesions develop. Gadolinium diethylenetriaminepentaacetic acid (Gd)-enhanced MRI and MR diffusion studies were performed monthly for 1 year in five multiple sclerosis patients with clinically and radiologically active disease. The ADC(av) was calculated at each time point of the study (before, during and after lesion appearance on Gd-enhanced scans) for each new enhancing lesion, and for regions matched for size and position in the contralateral NAWM. A steady and moderate increase in ADC(av) in prelesion NAWM was observed, which was followed by a rapid and marked increase at the time of Gd enhancement and a slower decay after the cessation of enhancement. In matched contralateral NAWM regions there was a significant but milder increase in ADC(av) at the time of the first noted lesion enhancement. These findings indicate that new focal lesions associated with frank BBB leakage are preceded by subtle, progressive alterations in tissue integrity beyond the resolution of conventional MRI. The increases in ADC(av) in anatomically matched contralateral regions after lesions have appeared supports the concept that structural damage in lesions causes damage or dysfunction in connected areas of NAWM.

Relationship between tumour necrosis factor-alpha (TNFalpha) production and a specific multiple sclerosis (MS) associated TNF gene haplotype.

OBJECTIVE: To determine if monocyte TNFalpha production from patients homozygous for a specific MS associated TNF gene haplotype is different from that produced in patients either heterozygous for, or without this haplotype. BACKGROUND: The balance between pro- and anti-inflammatory cytokines is important in the clinical outcome of inflammatory reactions. Levels of TNFalpha, a pro-inflammatory cytokine, is raised in MS as well as being found in acute and chronic MS lesions. A previous population based study in Northern Ireland with polymorphisms spanning the TNF gene region identified a conserved MS associated haplotype in relation to three markers (130: 118: 127 TNF d:a:b) for which 19 MS patients were homozygous. METHODS: Venous blood collected in EDTA to give a concentration of 10(-3) M was drawn from 16 patients with the conserved MS associated haplotype, 19 patients heterozygous for the haplotype and 17 patients without the haplotype. Mononuclear cells were separated and cultured by standard techniques and levels of TNFalpha and of TNF binding proteins I and II were determined by commercial enzyme-linked immunosorbent assays. RESULTS: There were no significant differences in TNFalpha production in the 3 h (P = 0.28) or 24 h cultures (P = 0.18) or following stimulation with interferon-gamma (P = 0.17) between the group positive for the conserved haplotype and the group negative for this haplotype. There was also no significant difference when compared to the heterozygote group. No association was found between the MS associated haplotype and levels of either TNF binding protein. A greater proportion of patients with the conserved haplotype had a benign clinical course (P = 0.06). CONCLUSION: We conclude that whilst a trend exists, we have found no significant association between peripheral TNFalpha production and a specific MS associated TNF haplotype in this population. Paradoxically this haplotype may also predict a more favourable clinical course.

Comparison of multiple sclerosis clinical subgroups using navigated spin echo diffusion-weighted imaging.

The apparent diffusion coefficient (ADC) of tissue provides an indication of the size, shape, and orientation of the water spaces in tissue. Thus, pathologic differences between lesions in multiple sclerosis (MS) patients with different clinical courses may be reflected by changes in ADC measurements in lesions and white matter. Twelve healthy subjects and 35 MS patients with a relapsing-remitting (n = 10), benign (n = 8), secondary progressive (n = 8) and primary progressive (n = 9) clinical course were studied. T2-weighted and post-gadolinium T1-weighted images were obtained using a 1.5 T Signa Echospeed magnetic resonance imaging (MRI) system. Diffusion-weighted imaging was implemented using a pulsed gradient spin echo (PGSE) sequence with diffusion gradients applied in turn along three orthogonal directions in order to obtain the average apparent diffusion coefficient (ADCav). Navigator echo correction and cardiac gating were used to reduce motion artifact. ADC maps were derived using a two point calculation based on the Stejskal-Tanner formula. Diffusion anisotropy was estimated using the van Gelderen formula to calculate an anisotropy index. MS lesions had a higher ADC and reduced anisotropy compared with normal appearing white matter. Highest ADC values were found in gadolinium enhancing lesions and non-enhancing hypointense lesions on T1-weighted imaging. MS white matter had a slightly higher ADC and lower anisotropy than white matter of healthy subjects. Lesion and white matter ADC values did not differ between patients with different clinical courses of MS. There was no correlation between lesion ADC and disability. Diffusion-weighted imaging with measurement of ADC using the PGSE method provides quantitative information on acute edematous MS lesions and chronic lesions associated with demyelination and axonal loss but does not distinguish between clinical subtypes of MS.

Serum soluble adhesion molecules in multiple sclerosis: raised sVCAM-1, sICAM-1 and sE-selectin in primary progressive disease.

Leucocyte invasion into the central nervous system in multiple sclerosis (MS) is complex, involving T-cell/endothelium interaction dependent upon initial adhesion mediated by molecules such as E-selectin, L-selectin, intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-(VCAM-1). Circulating levels of these can be measured by sensitive enzyme-linked immunoassay (ELISA) techniques. To assess whether serum concentrations of soluble adhesion molecules vary across the spectrum of patients with relapsing-remitting (RR), secondary progressive (SP) and primary progressive (PP) MS, we measured circulating levels of soluble (s)E-selectin, sL-selectin, sICAM-1 and sVCAM-1 in serum obtained from 78 PPMS patients, 71 patients with RRMS, 65 patients with SPMS and 66 patients with other neurological disease using commercially available ELISA systems. Levels of serum sVCAM-1 were significantly elevated in PPMS compared with RRMS in remission (P = 0.0001) and in relapse (P = 0.0001), whilst sICAM-1 was significantly elevated in PPMS compared with all other MS groups (vs SPMS, P = 0.006; vs RRMS in relapse, P = 0.003; vs RRMS in remission, P = 0.0001). Serum sE-selectin levels were significantly higher in PPMS compared with all other groups except inflammatory neurological disease (IND) [vs SPMS, P = 0.029; vs RRMS in relapse, P = 0.002; vs RRMS in remission, P = 0.001; vs non-inflammatory neurological disease (NIND), P = 0.002; vs IND, P = 0.076]. In PPMS there was no correlation between levels of any adhesion molecule and disability or disease duration. These results provide evidence for significant immunological heterogeneity in MS and suggest that different leucocyte/endothelial cell interactions may be active in various MS subgroups. It also challenges the hypothesis that PPMS is a less inflammatory form of the disease.

Genetic association studies of tumour necrosis factor alpha and beta and tumour necrosis factor receptor 1 and 2 polymorphisms across the clinical spectrum of multiple sclerosis.

Allelic association studies with microsatellite markers around the tumour-necrosis factor (TNF) genes have demonstrated significantly different allele distributions of TNF markers (a and b) between relapsing-remitting/secondary progressive multiple sclerosis (MS) (RR/SPMS) patients and normal controls. Considering the suspected genetic and immunological heterogeneity in MS, we tested this association in primary progressive MS (PPMS) patients. Elevated levels of serum soluble TNF receptors (sTNF-R) are reported in patients with gadolinium enhancing lesions, and animal models suggest a possible therapeutic role of sTNF-RI in MS. Thus we performed similar association studies using markers for the TNF-R genes. Gene association studies were carried out on 199-216 normal controls, 174 RR/SPMS patients and 102 PPMS patients using polymorphic dinucleotide repeat TNF markers (a, b and d), and separate markers for TNF-RI and TNF-RII. Forward primers were fluorescently labelled, polymerase chain reaction (PCR) products were analysed on a fluorescent fragment analyser, and Genescan 672 software was used for allele sizing. Samples were typed for HLA-DR antigens using PCR technology and sequence-specific oligonucleotide probes. TNFa marker allele distributions differed significantly between PPMS patients and controls (P = 0.028), largely attributable to an increase in the 118-bp TNFa allele in PPMS patients (P = 0.00024). Allele distributions were similar in PPMS and RR/SPMS patients (P = 0.91). Logistic regression analysis, however, indicated that these associations were not independent of that with HLA-DRB1*15. For the TNFb marker, the 127-bp allele showed association with both patient categories (PPMS vs. controls, P = 0.010; RR/SPMS vs. controls, P = 0.027), whilst the 128-bp allele occurred more frequently in controls (PPMS vs. controls, P = 0.036: RR/SPMS vs. controls, P = 0.0009). As with the TNFa 118 bp allele, the association with TNFb was not independent of the HLA association. No association occurred with the TNFd marker, and there were also no significant differences in allele frequencies between MS groups and controls regarding the marker for TNF-RI or TNF-RII. In Northern Irish patients the TNF contribution to MS genetic susceptibility is therefore similar across the clinical spectrum of the disease but is not independent of the association with HLA-DRB1*15.

Elevated serum and CSF levels of soluble CD30 during clinical remission in multiple sclerosis.

OBJECTIVE: To ascertain the presence of the Th2 response in MS patients by evaluating the level of soluble (s) CD30 across the clinical spectrum of MS and during relapse and remission. BACKGROUND: MS is considered a T-cell-mediated disorder with the immune attack dominated by a Thl cytokine response. Elevated levels of sCD30 have been associated with CD4+ cells that secrete Th2-type cytokines. METHODS: Levels of sCD30 were determined in the serum and CSF of patients with primary progressive MS, secondary progressive MS, relapsing-remitting MS (RRMS), both in relapse and remission, and in patients with other inflammatory neurologic disease (IND) and noninflammatory neurologic disease (NIND). None of the patients were on immunomodulatory treatment. RESULTS: Higher serum levels of sCD30 were detected in all MS subgroups and IND patients compared with NIND patients. RRMS patients in remission had significantly higher levels than those in relapse (median, 45.7 U/mL versus 18.3 U/mL; p = 0.04). Significantly higher CSF levels were also found in all groups, except those with RRMS in relapse compared with NIND patients. Again, RRMS patients in remission had higher CSF sCD30 levels compared with those in relapse (median, 4.0 U/mL versus 3.0 U/mL; p = 0.08). CONCLUSIONS: Serum and CSF levels of sCD30 are increased in MS, particularly during remission. The results provide additional evidence for the presence of a Th2 response and indicate that sCD30 may be of value as a marker of lesion resolution.

Methylprednisolone-induced neutrophil leukocytosis--down-modulation of neutrophil L-selectin and Mac-1 expression and induction of granulocyte-colony stimulating factor.

The mechanisms underlying corticosteroid-induced neutrophil leukocytosis are not fully understood; however, leukocyte/endothelial cell adhesion molecule interactions are known to be key to the movement of neutrophils within and out of the vasculature. This study was designed to investigate the effects of corticosteroids on neutrophil adhesion molecules in relation to neutrophil leukocytosis. Circulating neutrophil counts, neutrophil L-selectin and Mac-1 expression (measured by flow cytometry), soluble L-selectin, and granulocyte-colony stimulating factor concentrations were determined in 15 multiple sclerosis patients receiving intravenous methylprednisolone prior to and at 6 and 24 h following the initial 500-mg dose. A follow-up sample was obtained 48 h after the 5-day therapeutic course. Neutrophil counts were elevated at 6 h (threefold) and 24 h (twofold). This was associated with a 40% reduction in L-selectin expression at 6 and 24 h and a 35% reduction in Mac-1 expression at 6 h. Serum granulocyte-colony stimulating factor levels were increased (6 h: threefold; 24 h: twofold), whereas soluble L-selectin concentrations were unaltered. All of the above parameters had returned to basal levels in the follow-up sample. Short-term in vitro cultures (6 and 24 h) of blood samples from untreated multiple sclerosis patients and controls with 0.01 mg/ml methylprednisolone resulted in minimal reductions in neutrophil L-selectin and Mac-1 and no change in soluble L-selectin. Granulocyte-colony stimulating factor induced Mac-1 expression in a dose-dependent manner, whereas L-selectin expression was unaffected or reduced at high concentrations. Reduction in neutrophil L-selectin and Mac-1 expression following methylprednisolone infusion may cause decreased adhesion of marginated neutrophils and/or reduced capacity of neutrophils to migrate from the vasculature. Additionally, the induction of granulocyte-colony stimulating factor may contribute to neutrophil production and release into the circulation.

Raised CSF levels of soluble adhesion molecules across the clinical spectrum of multiple sclerosis.

Endothelial activation is considered an important step in multiple sclerosis (MS) lesion formation, elevated cerebrospinal fluid (CSF) and serum levels of certain adhesion molecules being associated with varying stages of disease activity and clinical course. CSF and serum sVCAM-1, sICAM-1, sE-selectin and sL-selectin were measured by ELISA in 16 primary progressive (PPMS), 16 secondary progressive (SPMS) and 43 relapsing-remitting MS patients (RRMS) and compared with 20 inflammatory (IND) and 46 non-inflammatory neurological disease (NIND) controls. CSF sVCAM-1 and sICAM-1 were increased in all MS groups vs. NIND with no significant differences between the MS groups. CSF sE-selectin (p = 0.007) and the sE-selectin index (p = 0.01) were elevated in PPMS vs. RRMS in relapse, whilst serum sE-selectin was significantly raised in PPMS compared to RRMS in remission (p = 0.005), RRMS in relapse (p = 0.004), NIND (p = 0.03) and IND (p = 0.05). Adhesion molecule levels in both progressive MS groups were similar. These results provide evidence for a distinct inflammatory component in PPMS and for immunological heterogeneity between the clinical subgroups of MS.

Effects of intravenous methylprednisolone therapy on leukocyte and soluble adhesion molecule expression in MS.

Intravenous methylprednisolone (IVMP) may inhibit inflammatory cell recruitment to active MS lesions by effects on leukocyte or endothelial cell adhesion molecule expression. We investigated 15 MS patients in relapse receiving a 5-day course of IVMP (500 mg/day) and 15 normal subjects. Patients' blood samples were obtained pretreatment, at 6 and 24 hours after the first dose, and 48 hours after completion of therapy. Levels of L-selectin, leukocyte functional antigen 1 (LFA-1), Mac-1, and very late activation antigen 4 (VLA-4) expression were determined on alphabeta and gammadelta T cells and monocytes by dual-color immunofluorescent flow cytometry. Serum levels of soluble (s) L-selectin, sE-selectin, soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured by ELISA. There was a marked decrease in the T-cell and monocyte counts at 6 hours after therapy, with recovery to baseline at 24 to 48 hours. Adhesion molecule expression was normal on circulating T cells and monocytes in active MS. IVMP resulted in significant changes in the percent adhesion molecule expression on monocytes: increased L-selectin expression at 24 hours, decreased Mac-1 expression at 6 hours, and decreased VLA-4 expression at 6 hours and 24 hours following treatment. T-cell adhesion molecule expression was unaffected by the therapy. Serum sE-selectin was reduced at 6 hours and 24 hours following treatment. IVMP alters the distribution and kinetics of monocyte adhesion molecule expression and endothelial cell release of E-selectin, which may limit monocyte recruitment to areas of tissue destruction in MS.

Tumour necrosis factor microsatellites show association with multiple sclerosis.

The TNF alpha and beta genes are located between the class I and class III HLA loci and have been implicated in the pathogenesis of multiple sclerosis. We carried out allelic association analysis using four microsatellite markers localised within a 20 kb region around the TNF genes. The study was performed on DNA samples from 189 clinically definite MS patients and 206 normal controls, all of Northern Irish origin. The allele distributions for the TNFa and b markers were significantly different between the MS patients and controls (P = 0.014, df 8 and 0.0019, df 4, respectively). The difference could largely be attributed to increases in the TNFa 118 bp allele and the TNFb 127 bp allele in MS patients, with a conserved MS associated haplotype (130:118:127 TNF d:a:b). Of the 19 patients homozygous for this haplotype, 17 were HLA typed and results suggested that the TNF haplotype association can occur independently of inheritance of DR2. Transmission disequilibrium testing (TDT) also supported the TNFa 118 bp association. These results suggest that in this population TNF is possibly one of the genetic factors contributing to MS susceptibility.

Methylprednisolone attenuates interferon-beta induced expression of HLA-DR on monocytes.

The effect of methylprednisolone on constitutive and interferon-beta (IFN-beta) induced HLA-DR expression on monocytes from multiple sclerosis (MS) patients was investigated. Constitutive HLA-DR expression was reduced by 50% following a single dose (500 mg) of intravenous methylprednisolone (IVMP). Stimulation with natural IFN-beta, in vitro, resulted in a 20 fold increase in HLA-DR expression. Following IVMP, IFN-beta inducible HLA-DR levels were reduced (non-significantly) by 20-30%. Experiments in which monocytes from normal subjects and MS patients were pre-treated in vitro with methylprednisolone prior to IFN-beta stimulation revealed that induction of HLA-DR was significantly inhibited; in contrast, IFN-beta induced HLA-DR expression was not down-regulated following subsequent in vitro treatment with methylprednisolone. These findings suggest that the immunomodulatory effects of IVMP could be attenuated in MS patients receiving regular IFN-beta therapy.

T-cell receptor alpha, beta, gamma, and delta chain gene microsatellites show no association with multiple sclerosis.

Genetic predisposition to multiple sclerosis (MS) is determined, in part, by certain HLA genotypes, but the contribution of T-cell receptor (TCR) germline polymorphisms to MS susceptibility is less clear. Reports of disease associations with restriction fragment length polymorphisms of TCR alpha and beta chain genes have been difficult to confirm, and little data is available on the influence of the TCR gamma delta germline in MS. We investigated the TCR alpha, beta, gamma, and delta chain genes of Northern Irish patients with MS using four microsatellite markers of high heterozygosity. There were similar allele frequencies in patients and controls for all microsatellites studied. We conclude there is no convincing evidence for an association of MS with TCR alpha, beta, gamma, and delta chain gene polymorphisms.

CD4 subsets (CD45RA/RO) exhibit differences in proliferative responses, IL-2 and gamma-interferon production during intravenous methylprednisolone treatment of multiple sclerosis.

Phytohaemagglutinin (PHA)-induced proliferative responses, interleukin 2 (IL-2) and gamma-interferon production were determined in purified CD4CD45RA and CD4CD45RO lymphocytes isolated by immunomagnetic bead separations from normal subjects and multiple sclerosis (MS) patients. Significantly higher proliferative activities were observed for CD4CD45RA cells compared with the corresponding CD4CD45RO cell population in normal subjects and MS patients. CD4CD45RA lymphocyte proliferative responses declined by 50% 3 h following a single dose (500 mg) of intravenous methylprednisolone (IVMP). At 24 h, levels were similar to those determined pre-therapy, as were the levels observed 24 h after a 5-day course (500 mg daily) of IVMP. In contrast, CD4CD45RO cells were unaffected by IVMP. In vitro incorporation of methylprednisolone (10(-6) M) to cell cultures resulted in a modest reduction in proliferative activities of both CD4 subsets. In MS patients subnormal levels of IL-2 and gamma-interferon were observed in PHA-stimulated cultures of CD4CD45RA and CD4CD45RO cells. Following 5 days of IVMP therapy, IL-2 and gamma-interferon production was similar to that observed in CD4CD45RA and CD4CD45RO cells from normal subjects. IVMP therapy causes selective, but transient, inhibition of CD4CD45RA lymphocyte proliferative responses and enhancement of PHA-induced IL-2 and gamma-interferon production by both CD4CD45RA and CD4CD45RO cells.

Serum and cerebrospinal fluid levels of soluble adhesion molecules in multiple sclerosis: predominant intrathecal release of vascular cell adhesion molecule-1.

Activated cerebral vascular endothelial cells express leukocyte, vascular cell, and intracellular adhesion molecules (E-selectin, VCAM-1 and ICAM-1) which facilitate leukocyte adhesion to endothelium and migration into inflammatory lesions. Paired serum and cerebrospinal fluid (CSF) levels of soluble (s) E-selectin, sVCAM-1 and sICAM-1 were determined by ELISA in patients with clinically definite MS in relapse, and patients with other inflammatory (IND) and non-inflammatory neurological disease (NIND). CSF levels of sVCAM-1 and sICAM-1 were significantly increased in MS patients compared to IND and NIND patients. Elevation of CSF sVCAM-1 in MS patients was the most marked finding (P = 0.0001) and an increased sVCAM-1 index indicated that this was due to intrathecal release of sVCAM-1. There were no differences in serum and CSF sE-selectin levels between the study groups. Measurement of the sVCAM-1 index may provide a marker of disease activity in patients with clinically definite MS.

Evaluation of formulae for CSF IgG synthesis using data obtained from two methods: importance of receiver operator characteristic curve analysis.

AIMS: To determine the clinical performance of three cerebrospinal fluid (CSF) IgG synthesis formulae using data obtained from two quantitation methods. METHODS: Receiver operator characteristic (ROC) analysis and decision index plots were used to compare a rate nephelometric (RN) and a rocket immunoelectrophoretic (RIEP) method for quantitating albumin and IgG for use in CSF IgG synthesis formulae. Further analysis was used to determine the most clinically accurate of these formulae for a diagnosis of multiple sclerosis with regard to technical accuracy and cost effectiveness. RESULTS: Values for albumin and IgG determined by RN gave better sensitivities and specificities than the RIEP method when applied to all three formulae; however, when the 95% confidence limits were considered, the difference was not significant. Using the RN method with an agreed "rule in" threshold value of 90% specificity, the IgG index gave the best clinical performance. CONCLUSION: ROC curve analysis and decision index plots provide valuable tools in assessing and comparing the clinical performance of new and existing laboratory assays.

Pharmacokinetics of flosequinan in patients with heart failure.

OBJECTIVE: The pharmacokinetics of flosequinan were studied in a group of 18 patients with chronic cardiac failure. RESULTS: After a single dose of 100 mg, Cmax of the parent compound (2.52 mg.l-1) was recorded at 1.4 h, and of the sulphone metabolite flosequinoxan at 21.7 h. The plasma elimination half lives of the parent compound (6.4 h) and of the metabolite (54.3 h) were prolonged compared to previous studies in normal volunteers. After repeated dose administration for 36 days, the kinetics of the parent compound and metabolite remained essentially unchanged with an expected significant accumulation of metabolite (Cmax 8.4 vs 3.21 mg.l-1). No adverse effects were observed. CONCLUSION: It is possible that altered drug kinetics in patients with heart failure, probably related to altered hepatic blood flow, could contribute to drug toxicity.

Transient immunomodulation by intravenous methylprednisolone treatment of multiple sclerosis.

The extent and duration of immunomodulation induced by high-dose corticosteroid treatment of clinical relapse of multiple sclerosis was investigated. Ten patients treated with a 5 day course of intravenous methylprednisolone (IVMP) (500 mg daily) were studied. Circulating lymphocyte subpopulations and mitogen-induced interleukin 2 (IL-2) and gamma-interferon (gamma-IFN) production were determined immediately before initiation of therapy (day 1), during therapy (24 h after first dose, day 2) and at 24 h and 1 week post therapy (days 6 and 12 respectively). T-cell subpopulation (CD3, CD4, CD8, CD4CD45RA, CD4CD45RO) levels fell within 24 h of initiation of therapy, rebounded above pretreatment levels at day 6 and normalised 1 week post therapy. Despite a reduction in total T-cell numbers during treatment, the gamma delta T-cell subpopulation was not significantly altered. HLA-DR expression on B cells and monocytes declined transiently on day 2 to approximately 50% of pretherapy levels. IL-2 and gamma-IFN production were reduced during therapy but returned to baseline levels by 24 h post therapy. The effects of IVMP on lymphocyte distribution and function appear to be short-lived and, therefore, may not be responsible for the rapid improvement associated with this form of treatment.