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Biomedical subjects

D Rühl

Publications and source records attributed to D Rühl.

9 recordsLinked to original sources
PubMed2001

[Speech development and intelligence in autism. How uniform is Asperger syndrome?].

Since the introduction of a separate diagnosis for Asperger's syndrome in the ICD-10 and DSM-IV classification systems, a controversial debate has continued on whether Asperger's syndrome is a specific, clearly distinguishable disorder within the autistic spectrum or whether it represents a milder phenotypical variation of autism. The effect on the amount of autistic symptoms of the variables language delay and level of intelligence was analyzed within a sample of individuals exhibiting autism diagnosed by standardized methods. Both variables showed a significant effect on the degree of autistic symptoms in that impairments in social interaction were less noticeable. In addition, a subsample of individuals exhibited symptoms assumed to be characteristic for Asperger's syndrome. The findings support the assumption that autism and Asperger's syndrome represent "extreme points" on a scale of severity, which leads to the suggestion that the classification of different subtypes of autism could be abandoned in favor of a dimensional (multiaxial) approach.

Adolescent↗
PubMed1997

Molecular genetic analysis of the FMR-1 gene in a large collection of autistic patients.

A genetic etiology in autism is now strongly supported by family and twin studies. A 3:1 ratio of affected males to females suggests the involvement of at least one X-linked locus in the disease. Several reports have indicated an association of the fragile X chromosomal anomaly at Xq27.3 (FRAXA) with autism, whereas others have not supported this finding. We have so far collected blood from 105 simplex and 18 multiplex families and have assessed 141 patients by using the Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observation Scale, and psychometric tests. All four ADI-R algorithm criteria were met by 131 patients (93%), whereas 10 patients (7%) showed a broader phenotype of autism. Southern blot analysis was performed with three different enzymes, and filters were hybridized to an FMR-1-specific probe to detect amplification of the CCG repeat at FRAXA, to the complete FMR-1 cDNA probe, and to additional probes from the neighborhood of the gene. No significant changes were found in 139 patients (99%) from 122 families, other than the normal variations in the population. In the case of one multiplex family with three children showing no dysmorphic features of the fragile X syndrome (one male meeting 3 out of 4 ADI-algorithm criteria, one normal male with slight learning disability but negative ADI-R testing, and one fully autistic female), the FRAXA full-mutation-specific CCG-repeat expansion in the genotype was not correlated with the autism phenotype. Further analysis revealed a mosaic pattern of methylation at the FMR-1 gene locus in the two sons of the family, indicating at least a partly functional gene. Therefore, we conclude that the association of autism with fragile X at Xq27.3 is non-existent and exclude this location as a candidate gene region for autism.

Autistic Disorder↗
PubMed1997

Influence of fluorescent labelling of polystyrene particles on phagocytic uptake, surface hydrophobicity, and plasma protein adsorption.

PURPOSE: To investigate the influence of fluorescent labelling of polystyrene particles on phagocytic uptake, surface hydrophobicity and protein adsorption. METHODS: Phagocytic uptake was analysed using chemiluminescence. Hydrophobicity was quantified by adsorption measurements of a hydrophobic dye. Protein adsorption was evaluated by two-dimensional electrophoresis. RESULTS: Commercially available fluorescently labelled particles showed marked differences when compared to unlabelled particles: phagocytic uptake and surface hydrophobicity of labelled particles were diminished. Also the plasma protein adsorption pattern was found to be different from the unlabelled particles: for example, the amount of fibrinogen adsorbed was strongly reduced on the labelled particles. On the other hand, some unknown proteins could be detected on the fluorescently marked particles. In contrast, plain polystyrene particles and labelled ones could be successfully synthesised by Paulke which did not show any considerable differences in phagocytic uptake, surface hydrophobicity and protein adsorption. Polysorbate 20 added as stabilizer to particle suspensions led to completely different behaviour of the particles: the particles showed altered protein adsorption patterns, dominated by immunoglobulins and especially by apolipoproteins. Furthermore, these particles were not phagocytized at all. CONCLUSIONS: Surface hydrophobicity and phagocytic uptake in vitro as well as the interactions with plasma proteins of commercially available polystyrene particles were strongly affected by fluorescent labelling. Particles synthesised by Paulke remained unchanged after labelling. The results show the importance of thorough surface characterization for using particles in test systems in vitro and in vivo.

Adsorption↗
PubMed1997

Cytotoxicity of solid lipid nanoparticles as a function of the lipid matrix and the surfactant.

PURPOSE: Assessment of the in vitro cytotoxicity of solid lipid nanoparticles (SLNs) as a function of lipid matrix (Dynasan 114, Compritol ATO 888), and stabilizing surfactant (poloxamers, Tween 80, soya lecithin, and sodium dodecyl sulphate). Comparison with other colloidal carriers should determine their potential use in the clinic. METHODS: SLNs were produced by high pressure homogenisation. Cytotoxicity was assessed by measuring the viability of HL60 cells and human granulocytes after incubation with SLNs. Particle internalisation was quantified by chemiluminescence measurements. RESULTS: The nature of the lipid had no effect on viability; distinct differences were found for the surfactants. Binding to the SLN surface reduced markedly the cytotoxic effect of the surfactants, e.g., up to a factor of 65 for poloxamer 184. The permanent HL60 cell line-differentiated from cells with granulocyte characteristics by retinoic acid treatment-yielded results identical to freshly isolated human granulocytes. In general, the SLNs showed a lower cytotoxicity compared to polyalkylcyanoacrylate and polylactic/glycolic acid (PLA/ GA) nanoparticles. CONCLUSIONS: Because the results are identical when using human granulocytes, differentiated HL60 cells can be used as an easily accessible in vitro test system for i.v. injectable SLN formulations. The SLNs appear suitable as a drug carrier system for potential intravenous use due to their very low cytotoxicity in vitro.

Cell Survival↗
PubMed1996

The standardized diagnosis of autism, Autism Diagnostic Interview-Revised: interrater reliability of the German form of the interview.

The feasibility and reliability of the German form of the revised parental interview to diagnose autism (Autism Diagnostic Interview-Revised, ADI-R) was investigated in this study. Brief examples of the description of formerly and currently used diagnostic guidelines are given and the outline of the interview algorithm which establishes thresholds for inclusion criteria. An excellent-to-good reliability could be demonstrated for the main symptoms according to the classification rules of the ICD-10 and DSM-IV for a sample of autistic subjects at different ages and intellectual levels. The results approve the use of this interview for research and clinical purposes.

Adolescent↗
PubMed1995

[The intelligence structure of autistic persons].

In a research project on the genetics of autistic disorders 115 subjects were examined. An autistic disorder was diagnosed in 102 of the subjects using the standardized Autism Diagnostic Interview (ADI; Le Couteur et al., 1989/ADI-R; Lord et al., 1994). The WAIS-R or WISC-R could be administered to 42 of the subjects. The mean full-scale IQ was 84.4, slightly below the range of normal intelligence. The mean verbal IQ (89.3) was considerably higher than the performance IQ (78.9). Analysis of the subtest patterns showed the highest scores to be in those subtests measuring knowledge of dates and facts and visuospatial abilities. The lowest scores were on subtests requiring an understanding of social relations and the ability to understand concrete social actions. This subtest pattern confirms results of other studies on the intelligence of individuals with autism and was independent of gender and level of intelligence. The subtest pattern appears to be specific for autistic disorder; it has been interpreted with reference to the theory of "weak central coherence" (Frith, 1989; Shah & Frith, 1993), which postulates that in autistic individuals stimulus perception and processing occurs independently of the general context. The results suggest that the differentiation between different types of autistic disorders should be abandoned in favor of a continuum of autistic disorders with differing degrees of severity.

Adolescent↗