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Biomedical subjects

E Schuller

Publications and source records attributed to E Schuller.

At least 37 records · Page 2Linked to original sources

Photopolymerization of Acrylate Films under an Imposed Spatial Irradiation: Thermodynamics of Relief Self-Development

UV irradiation through a lined mask of acrylate-based self-developing materials leads to the formation of a relief in the irradiated areas. Investigation of the effect of various properties, through a known two-layer model, showed the paramount importance of surface state on relief height. Both relief height and inhibition time of the growing kinetics are shown to be directly dependent on two surface properties: surface free energy and viscosity of the condensed state of the gaseous atmosphere adjoining the film.

Journal Article↗

Molecular heterogeneity of classical and Duarte galactosemia: mutation analysis by denaturing gradient gel electrophoresis.

Classical galactosemia is caused by one common missense mutation (Q188R) and by several rare mutations in the galactose-1-phosphate uridyltransferase (GALT) gene. The most common variant of GALT, the Duarte variant, occurs as two types, Duarte-1 (D-1) and Duarte-2 (D-2), both of which carry the sequence change N314D. D-1 increases, whereas D-2 decreases GALT activity. To study the molecular genetics of classical and Duarte galactosemia, we analyzed the GALT mutations in 30 families with classical galactosemia, in 10 families with the D-2 variant and in 3 individuals carrying the D-1 allele by denaturing gradient gel electrophoresis (DGGE). DGGE detected 59 of the 60 classical galactosemia alleles. Q188R accounted for 60%, K285N accounted for 28% of these alleles. Eight novel candidate galactosemia mutations were found. On all D-2 alleles N314D occurred in cis with two intronic sequence changes, on the D-1 alleles in cis with a neutral mutation in exon 7. We conclude that the mutations causing galactosemia are highly heterogeneous and that K285N is a second common galactosemia mutation in our population.

Adult↗

Multiple sclerosis and intrathecal IgA synthesis.

A clinically definite diagnosis of multiple sclerosis was done in a 61 year-old woman who displayed severe cerebellar and pyramidal tract involvement. Symptoms developed 5 years before with unsteadiness of gait and difficulties in walking. Diagnosis was supported by evoked potentials studies and magnetic resonance imaging. However, the cerebrospinal fluid (CSF) analysis was very unusual. CSF albumin and IgG concentrations were normal, as well as the IgG index. In contrast, the IgA level and the IgA index were markedly increased and the local synthesis of IgA was estimated at 31.36 mg/l. Reduction by dithiotreitol did not change the IgA level. On affinity immunoblots, oligoclonal IgA bands were not detected but oligoclonal IgG bands were present. The strong local production of IgA in this patient seems to be therefore polyclonal.

Dithioerythritol↗

Long-term treatment of multiple sclerosis with IgG immunotherapy.

Thirty-five patients with a clinically [1] definite multiple sclerosis (M.S.) were treated in an open trial (1975-1993) with a standard dose preparation of total IgG (5 grams per week) by intra-muscular or intravenous injection. This treatment was used in 35 patients: during 3 to 16 years. Using Kurtzke's disability scale the results were: 1) a significant deterioration (loss of 1 grade in the Kurtzke's disability scale) only 14 years after the entry in the trial. 2) regarding current therapeutic results: improvement for 8 patients, deterioration for 18, and stability for 9. Neither the age at the M.S. onset and at the entry, nor the duration of the disease, nor the disability score at the entry were factors modifying significantly the efficacy of the treatment. The comparison of these results with previous predictive studies (Confavreux, Weinshenker) suggests a significant reduction of M.S. progression, with an increase of the functional independence period. No side-effects were observed, and this immunotherapy, which may be convenient for home care, must be tested in properly controlled trials.

Adult↗

[Use of immunoglobulins G in the treatment of nervous system diseases].

Short term and long term beneficial effects of IgG administration have been studied in 4 groups of neuro-immunological diseases: Polymyositis, dermatomyositis and myasthenia. Peripheral neuropathies (myelinopathies), primarily in Guillain-Barré syndrome and in chronic inflammatory polyneuropathy. Children intractable Epilepsy. Multiple Sclerosis. Actual results are in favor of an objective and marked improvement (after 1 or 2 months) in the first 2 groups using intravenous IgG. In M.S. patients, the short term treatment of bouts (especially: optic neuritis) seems promising. Results of the only one long term (later than 10 years) trial are in favor of a significant slowing of the progression of M.S. comparatively to the predictive curve of disease.

Epilepsy↗

A sensitive time-resolved immunofluorometric assay for the measurement of apolipoprotein B in cerebrospinal fluid. Application to multiple sclerosis and other neurological diseases.

Although low density lipoprotein receptors have been described on oligodendrocytes, apolipoprotein B was thought to be absent or present in only very small amounts in cerebrospinal fluid (CSF). Several immunoassays have been used for the measurement of apolipoprotein B in serum. However, the majority of methods cannot be used to measure small amounts of apolipoprotein B in CSF. In this study, we describe a highly sensitive time resolved immunofluorometric assay (TR-IFMA) using europium as label (detection limit: 0.3 microgram/l). The reliability of the TR-IFMA for the measurement of apolipoprotein B was first studied in serum. Serum and CSF apolipoprotein B concentrations were then determined in subjects free of neurological disorders and in patients with multiple sclerosis. Local intrathecal apolipoprotein B synthesis was calculated. Although the high sensitivity of the TR-IFMA allowed low amounts of apolipoprotein B in CSF to be detected (0.11 +/- 0.06; 0.12 +/- 0.06 mg/l in controls and multiple sclerosis patients, respectively), no apolipoprotein B could be detected in CSF by electroimmunodiffusion. As suggested by the blood/CSF apolipoprotein B ratio (about 6000), no apolipoprotein B synthesis was observed by both using apolipoprotein B index and formula. This indicates its probable serum origin. Moreover, there was no difference between controls and multiple sclerosis patients in CSF, serum, blood/CSF, index, and local intrathecal apoliprotein B synthesis. Finally, these results suggest that the role of apolipoprotein B in lipid transport in the central nervous system may be questionable.

Adult↗

Oligoclonal beta-galactoside-binding immunoglobulins antigenically related to 14 kDa lectin in human serum and cerebrospinal fluid: purification and characterization.

1. An antiserum raised against a 14 kDa beta-galactoside specific lectin from human brain (HBL14) was used to probe blots from samples of serum and cerebrospinal fluid. The only HBL14-immunoreactive material detected was heavy and light chains of a beta-galactoside-binding IgG fraction (lectin-like IgG). 2. Lectin-like IgG, as well as IgG Fab fragments, compete with HBL14 for binding either to anti-HBL14 antibody or to a lactosyl polyacrylamide-based copolymer. 3. Purification of lectin-like IgG was obtained by affinity chromatography on immobilized rabbit anti-lectin immunoglobulins. The carbohydrate-binding specificity of the purified molecules was restricted to beta-Gal-containing structures and close to the HBL14 one.

Amino Acid Sequence↗

Apolipoprotein (a) levels and atherogenic lipid fractions in relation to the degree of urinary albumin excretion in type 2 diabetes mellitus.

The relationship between serum lipids, apolipoprotein levels including apolipoprotein (a) to albumin excretion rate (AER) in 52 (17 male, 35 female) type 2 diabetic patients was studied. Patients were classified in groups as follows: (1) patients with normal AER (< 30 mg/24 h); (2) patients with microalbuminuria (AER 30-300 mg/24 h), and (3) patients with macroalbuminuria (AER > 300 mg/24 h). Apolipoprotein B levels were significantly (p < 0.05) elevated in the patients with macroalbuminuria compared to the normoalbuminuric group. Further, we observed a significant correlation between total cholesterol, low-density lipoprotein cholesterol, as well as apolipoprotein B levels to the degree of AER. No correlation between apolipoprotein (a) levels and AER, which is in contrast to recently published data for type 1 diabetic patients, was found. Systolic blood pressure was significantly higher (p < 0.002) in the patients with micro- and macroalbuminuria compared to the group with normal albumin excretion, whereas no relationship between diastolic blood pressure and albuminuria was found. We conclude that elevated increased atherogenic lipid fractions in addition to systolic hypertension may contribute to an increased cardiovascular risk in type 2 diabetic patients with proteinuria.

Aged↗

Intrathecal synthesis of the anti-Hu antibody in patients with paraneoplastic encephalomyelitis or sensory neuronopathy: clinical-immunologic correlation.

We studied the intrathecal synthesis of the anti-Hu antibody (also called type 1 antineuronal nuclear autoantibody) in 14 patients with isolated paraneoplastic subacute sensory neuronopathy (SSN) and 16 with paraneoplastic encephalomyelitis (PEM). Patients with PEM had higher anti-Hu titers in the CSF (p = 0.003) but not in the serum than those with SSN. Only one patient (7%) with SSN had a positive intrathecal anti-Hu antibody synthesis whereas this was present in 14 (88%) of the 16 patients with PEM (p < 0.0001). The correlation between the intrathecal production of anti-Hu antibodies and PEM supports the role of autoimmune mechanisms in the pathogenesis of PEM. The absent intrathecal synthesis of anti-Hu antibodies in patients with SSN suggests easier accessibility of the systemic immune reaction to the sensory neurons probably due to the partial absence of blood-nerve barrier in the dorsal root ganglia.

Aged↗

[Cerebral lymphoma in AIDS: clinical study and clinicopathological correlations].

We report the natural history of 17 brain lymphomas (11 primary, 6 disseminated) from a post-mortem series of 130 patients with AIDS. Primary lymphomas appeared lately in the course of AIDS. They were often associated with a severe T-cell immunodepression and with more frequent opportunistic disorders than disseminated lymphomas. Associated Kaposi's sarcomas were surprisingly frequent. All patients presented with neurological manifestations. Heterogeneous features were seen at CT examination. The CSF was abnormal in 12/13 cases, with an increase of protein contents and secretion of immunoglobulins; it contained activated lymphocytes in 5/6 cases of disseminated lymphomas, and malignant cells in only one case. Cellular density never exceeded 8/mm3 for primary lymphomas, and the lymphocytes were considered normal. The pre-mortem diagnosis of cerebral lymphomas was made in five patients, with a time lapse of 1 to 7 months between the first neurological symptoms and death, and of 5 to 30 days between the diagnosis and death. Cerebral biopsy was diagnostic in 4 cases of primary cerebral lymphomas. In only 1/6 patients with disseminated lymphomas, the diagnosis had been made when the patient was still alive, based on CSF and bone marrow lymphomatous infiltrations. The diagnosis of cerebral lymphoma (7 primary, 5 disseminated) was post-mortem in 12 cases. It was made only at microscopic examination in 2/12 cases of primary lymphomas. The histopathological study frequently showed a multicentric involvement, and always an immunoblastic cell type with plasmablastic differentiation and frequent medium size cells. Marked gliosis and significant necrosis were often observed. Neuropathological lesions associated with HIV-1 infection (toxoplasmosis, CMV and HIV-1 encephalitis) were seen in 8 cases with primary lymphomas.

Adult↗

Intrathecal synthesis of beta 2-microglobulin and lysozyme: differential markers of nervous system involvement in patients infected with human immunodeficiency virus type 1.

beta 2-Microglobulin and lysozyme were determined in paired serum and cerebrospinal fluid samples from 137 patients, using immunofluorometry and ELISA, respectively. Of these patients, 54 were infected by human immunodeficiency virus type 1 (HIV1) (including 20 AIDS dementia patients), 73 were HIV1-seronegative with neurological diseases (meningitis (n = 10), multiple sclerosis (n = 29), other neurological diseases (n = 34)) and 10 were controls. Intrathecal synthesis of beta 2-microglobulin occurred in each group. Conversely, lysozyme intrathecal synthesis was found only in meningitis (10/10) and in HIV1-infection (24/54). A pathological increase in beta 2-microglobulin intrathecal synthesis (> or = 2 mg/l) was observed in 45 patients (34 HIV1-infected patients and 11 HIV1-seronegative patients with neurological diseases). Serum concentration and intrathecal synthesis of beta 2-microglobulin were correlated only in the 20 AIDS dementia patients. The cerebrospinal fluid beta 2-microglobulin and lysozyme concentrations were correlated in the 54 HIV1-infected patients only. Blood CD4 + T-cell count was correlated negatively with beta 2-microglobulin intrathecal synthesis but not with lysozyme intrathecal synthesis. These data suggest that in the absence of any central nervous system opportunistic process the increase of beta 2-microglobulin intrathecal synthesis (> or = 2 mg/l) may be a reliable marker of central nervous system involvement in HIV1-infected patients. Intrathecal synthesis of lysozyme was related principally to HIV1-encephalitis and central nervous system opportunistic processes.

AIDS Dementia Complex↗

Time-resolved immunofluorometric assay of complement C3: application to cerebrospinal fluid.

Complement components have a role in various neurological disorders. Complement C3 can be measured by immunochemical methods, but only radioimmunoassays and electroimmunodiffusion assays (EIDs) are sufficiently sensitive to be applied to biological fluids in which the C3 concentration is low, especially cerebrospinal fluid (CSF). We report a sandwich-type time-resolved immunofluorometric assay (TR-IFMA) for C3 in CSF. The linearity (0.7-3650 micrograms/L) and intra- (CV < 4.8%) and inter-assay (CV < 10.9%) precision were satisfactory and the results agreed with those of EID. The assay is extremely sensitive (< 1 microgram/L) and its analytical range is large and well suited to clinical applications. This simple TR-IFMA is thus a nonisotopic alternative to radioimmunoassay for the quantification of complement C3 in CSF.

Adult↗