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Biomedical subjects

A M Landtblom

Publications and source records attributed to A M Landtblom.

17 recordsLinked to original sources
PubMed2003

Multiple sclerosis and exposure to organic solvents, investigated by genetic polymorphisms of the GSTM1 and CYP2D6 enzyme systems.

An association between multiple sclerosis (MS) and exposure to organic solvents has been discussed. Organic solvents are metabolised by enzyme systems like glutathione Stransferase M1 (GSTM1) and CYP2D6, which express polymorphisms in the general population. GSTM1 null genotype has been associated with solvent-induced chronic toxic encephalopathy. Our aim was to see if a defect in one of these enzyme systems could explain the association between MS and exposure to organic solvents. In our study, 50 patients with MS were investigated, including 24 who had been significantly exposed to organic solvents and 26 who were not exposed. Polymerase chain reaction-based methods were used for genotyping GSTM1 and CYP2D6 polymorphisms in leukocyte DNA. No differences in genetic predisposition were found between MS patients exposed and those not exposed to organic solvents regarding GSTM1 null or CYP2D6 poor metaboliser genotypes. The possible association between multiple sclerosis and solvents may not, as for chronic toxic encephalopathy, be explained by defects in these systems.

Adult↗
PubMed2003

Hypointensity in T2-weighted images of the basal ganglia in solvent-exposed patients with multiple sclerosis: clinical, MRI and CSF characteristics.

Several studies have indicated an association between MS and organic solvent exposure. Our objective was to analyse differences regarding cerebrospinal fluid (CSF) properties, magnetic resonance imaging (MRI) features and cerebral metabolites, measured by proton spectroscopy (1H-MRS), in 20 patients with spontaneous multiple sclerosis (MS) and in 20 patients with MS after solvent exposure; 15 healthy subjects served as controls. CSF examinations were retrospectively reviewed from the medical files. There were no significant differences in the CSF regarding pleocytosis, spinal-serum albumin ratio or mean extended IgG index. However, T2-weighted images of the solvent-exposed MS patients showed more hypointenseareas in the basal ganglia. Hypointensity on T2-weighted images of the basal ganglia in the solvent-exposed MS patients may correspond to neurodegeneration and could be an early event in MS.

Adult↗
PubMed2003

Genome-wide TDT analysis in a localized population with a high prevalence of multiple sclerosis indicates the importance of a region on chromosome 14q.

Epidemiological studies show that susceptibility to multiple sclerosis (MS) has a strong genetic component, but apart from the HLA gene complex, additional genetic factors have proven difficult to map in the general population. Thus, localized populations, where MS patients are assumed to be more closely related, may offer a better opportunity to identify shared chromosomal regions. We have performed a genome-wide scan with 834 microsatellite markers in a data set consisting of 54 MS patients and 114 healthy family members. A group of families from a small village were possible to track back to common ancestors living in the 17th century. We used single marker- and haplotype-based transmission disequilibrium test (TDT) analysis and nonparametric linkage analysis to analyze genotyping data. Regions on chromosomes 2q23-31, 6p24-21, 6q25-27, 14q24-32, 16p13-12 and 17q12-24 were found to be in transmission disequilibrium with MS. Strong transmission disequilibrium was detected in 14q24-32, where several dimarker haplotypes were in transmission disequilibrium in affected individuals. Several regions showed modest evidence for linkage, but linkage and TDT were both clearly positive only for 17q12-24. All patients and controls were also typed for HLA class II genes; however, no evidence for a gene-gene interaction was observed.

Chromosomes, Human, Pair 14↗
PubMed2003

Increased plasma homocysteine levels without signs of vitamin B12 deficiency in patients with multiple sclerosis assessed by blood and cerebrospinal fluid homocysteine and methylmalonic acid.

OBJECTIVE: The aim of this study was to evaluate if multiple sclerosis (MS) is associated with vitamin B12 (cobalamin) deficiency. METHODS: We measured serum vitamin B12, plasma folate, serum methylmalonic acid (MMA), plasma homocysteine (tHcy) and also cerebrospinal fluid (CSF) MMA and tHcy in 72 patients with MS and 23 controls. RESULTS: The mean plasma tHcy level was significantly increased in MS patients (11.6 micromol/L) compared with controls (7.4 micromol/L) (P = 0.002). Seven patients showed low serum vitamin B12 levels but only one of them had concomitant high plasma tHcy. None of them showed high serum MMA. Plasma or blood folate levels did not differ between MS patients and controls. We found no significant differences in mean values or frequency of pathological tests of serum B12, serum MMA, mean corpuscular volume (MCV), haemoglobin concentration, CSF tHcy or CSF MMA between patients and healthy subjects. There were no correlations between CSF and serum/plasma levels of MMA or tHcy. Serum vitamin B12, serum MMA, plasma tHcy, CSF Hcy or CSF MMA were not correlated to disability status, activity of disease, duration of disease or age. CONCLUSIONS: The relevance of the increased mean value of plasma tHcy thus seems uncertain and does not indicate functional vitamin B12 deficiency. We can not, however, exclude the possibility of a genetically induced dysfunction of the homocysteine metabolism relevant for the development of neuroinflammation/degeneration. Our findings indicate that, regardless of a significant increase in plasma tHcy in MS patients, the MS disease is not generally associated with vitamin B12 deficiency since we did not find any other factors indicating vitamin B12 deficiency. Analysis of CSF MMA and CSF tHcy, which probably reflects the brain vitamin B12 status better than serum, are not warranted in MS. We conclude that B12 deficiency, in general, is not associated with MS.

Adult↗
PubMed2001

Multiple sclerosis and ionizing radiation.

The etiology of multiple sclerosis (MS) may involve exposure to infectious, chemical or physical agents damaging the blood-brain barrier and an autoimmune reaction against myelin breakdown products. Here we report a pooled analysis of 174 MS cases and 815 population controls from two case-control studies with regard to such a potentially damaging exposure, namely X-ray examinations, radiological work and treatment with ionizing radiation. Exposure was assessed by questionnaires to the subjects. We obtained odds ratios of 4.4 (95% confidence interval, CI, 1.6-11.6) and 1.8 (95% CI 1.2-2.6) for radiological work and X-ray examinations, respectively; 5 cases, but no controls, in one of the studies had been treated with ionizing radiation. Our data and some other observations reported in the literature suggest a contributory role for ionizing radiation to the development of MS in some cases.

Adult↗
PubMed2001

Reduced quality of life among multiple sclerosis patients with sexual disturbance and bladder dysfunction.

OBJECTIVE: Physical disability explains only part of the reduced quality of life found among multiple sclerosis (MS) patients. Bladder dysfunction and sexual disturbance are frequent and distressing problems for MS patients. We therefore estimated the relationship between the presence and degree of sexual disturbance/bladder dysfunction and the patients' quality of life as measured by the SF-36 Health Survey. METHODS: We performed a cross-sectional study of all individuals with the onset of MS between 1976 and 1986 in Hordaland County, Norway. The disease duration at examination was 9-19 years; 194 patients (94%) participated. RESULTS: Fifty-three per cent of the patients with low physical disability (Expanded Disability Status Scale (EDSS) < or = 4.0) reported disease-related sexual disturbance and 44% had bladder dysfunction according to the Incapacity Status Scale. The corresponding figures for the patients with a high physical disability (EDSS > 4.0) were 86 and 81% respectively. The patients with sexual disturbance had markedly and significantly reduced scores on all eight SF-36 scales, this was after adjustment for disease development measured by the EDSS. The patients without sexual disturbance scored 0.5 s.d. lower than a normal population on the social functioning scale, whereas those with marked sexual disturbance scored 1.5 s.d. lower. Similar results were found for the patients with bladder dysfunction. CONCLUSION: Bladder and sexual problems are associated with a marked reduction in the quality of life, also among patients with otherwise low disability. This underlines the need for identifying and treating these problems.

Adult↗
PubMed2001

Education of referring doctors about sudden onset headache in subarachnoid hemorrhage. A prospective study.

OBJECTIVES: Forty percent of patients with aneurysmal subarachnoid hemorrhage have prodromal warning episodes and difficulties in identifying these events are repeatedly documented. Modifications of diagnostic and referral patterns through educational programs of local doctors may help to identify such patients before a major devastating rupture occurs. MATERIALS AND METHODS: A teaching program about sudden onset headache, targeting referring doctors, was systematically applied and its impact on early misdiagnosis of ruptured aneurysms was prospectively studied. RESULTS: Forty percent of all studied patients experienced a warning episode, manifested as apoplectic headache, prior to hospitalization. An initial diagnostic error was evident in 12% of the patients. Diagnostic errors were reduced by 77% as a result of continuous interaction between neurosurgeons and local physicians. CONCLUSION: Misdiagnosed warning episodes cause greater loss of lives and higher morbidity on a population basis than does delayed ischemic complications from vasospasm in aneurysmal SAH. Teaching programs focused on local physicians have a profound impact on outcome at low cost.

Diagnostic Errors↗
PubMed1998

Linkage and association analysis of genes encoding cytokines and myelin proteins in multiple sclerosis.

Several genetic factors are likely to play a role in the etiology of multiple sclerosis (MS). We used a candidate gene strategy in a study of polymorphic markers within or close to genes encoding cytokines (interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-4, IL-4 receptor (IL-4R), IL-10, transforming growth factor-beta1 and -beta2) and myelin proteins (2',3'-cyclic-nucleotide 3'-phosphohydrolase (CNP:ase), myelin associated glycoprotein, oligodendrocyte myelin glycoprotein, proteolipid protein) in 34 Swedish multiplex MS families and in 147 sporadic MS patients and 95 healthy controls. No evidence for linkage was observed in two-point linkage analysis. However, a slightly positive LOD score of 0.88 (theta = 0.01) for IFN-gamma was found. Affected pedigree member (APM) analysis indicated a possible linkage with TGF-beta2 (p = 0.008) and IL-4R (p = 0.043). None of the cytokine markers were associated with MS in case-control analysis. Our results suggest a possible importance of the TGF-beta2, IL-4R and IFN-gamma genes in MS.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1996

Organic solvents and multiple sclerosis: a synthesis of the current evidence.

To evaluate the possible relation between exposure to organic solvents and the development of multiple sclerosis, we carried out a best-evidence synthesis of the available information. We found 13 studies with varying methodology that included information on solvent exposure. In 10 of the studies, there were indications of an increased risk of multiple sclerosis in relation to solvent exposure. We made three selections of studies for both pooled analyses and meta-analyses. The relative risk point estimates that we obtained varied from 1.7 to 2.6. Our evaluation is consistent with the hypothesis that organic solvents may be a cause of multiple sclerosis.

Case-Control Studies↗
PubMed1996

Proton MR spectroscopy and MR imaging in acute and chronic multiple sclerosis--ringlike appearances in acute plaques.

PURPOSE: We wanted to compare the metabolite status of brain lesions in different clinical subtypes of multiple sclerosis (MS). Two acute MS lesions with ringlike appearances were also investigated. MATERIAL AND METHODS: Twenty-three clinically stable MS patients, 2 patients with acute relapses, and 15 healthy individuals were examined by MR imaging and localized proton MRS. RESULTS: No metabolite differences were seen in plaques of different subtypes. Decreased NAA/Cr and NAA/choline ratios as well as increased inositol/Cr ratios were observed in the plaques of the clinically stable or chronic active MS patients as compared with controls. The ring plaques had hyperintense cores with surrounding halos, separated from the cores by rings with low signal intensity in T2-weighted images. The core exhibited a prolonged T2 relaxation time. Proton spectra initially contained lactate. CONCLUSION: No differences between the metabolite status of nonacute plaques in different clinical subtypes could be detected. The ring plaques contained lactate signals indicating oedema, inflammation, and macrophage invasion, and may be transition forms between acute oedematous lesions and chronic demyelinated plaques.

Adult↗
PubMed1993

Multiple sclerosis and exposure to solvents, ionizing radiation and animals.

Earlier studies have indicated an association between multiple sclerosis and environmental factors, especially occupational exposure to solvents. The present study examined such relationships further. From medical files of hospitals in Kalmar and Jönköping, 91 cases of multiple sclerosis, diagnosed in 1983-1988, were identified from population registers corresponding to the catchment areas of the hospitals, and 348 referents were randomly drawn. The cases and referents answered a questionnaire concerning occupational exposure and animal contacts. The men had significantly elevated risks, determined from logistic odds ratios, for solvent exposure, occupational contact with dogs or cats, and leisure-time contact with caged birds. X-ray treatment and previous diseases were risk indicators among the women. For the men and women together, solvent exposure, radiological work, and previous diseases were associated with clearly elevated risks. Although the study concerned rather few subjects, the findings indicate that several exogenous factors might contribute to the development of multiple sclerosis.

Adult↗