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Biomedical subjects

F Müller

Publications and source records attributed to F Müller.

At least 235 records · Page 13Linked to original sources
PubMed1993

Contribution of periodontal receptors and food qualities to masseter muscle inhibition in man.

Previous studies of human muscle inhibition during chewing have shown that many factors contribute to the incidence and intensity of this reflex but few studies have been in a physiological context. During the first crushing cycle of brittle foods ipsilateral masseter muscle EMG, mandibular movement and vibration were recorded simultaneously in four healthy dentate subjects. Experiments were repeated before and during anaesthesia of the cheek teeth on the chewing side. The results suggest that vibration seems to be the most important factor in muscle inhibition during food crushing; conversely periodontal sensation, mandibular closing movement and the preload by the muscle at the onset of food fracture play a minor role.

Adult↗
PubMed1993

Experimental studies of adaptation to complete dentures related to ageing.

The assessment of a patient's capability to adapt to new dentures is still a challenge in the prosthetic treatment of geriatric patients. The aim of this study was to assess the relationship of age to manual motor ability as well as the mental concentration capacity in comparison to the oral motor ability and the capability to adapt to new dentures. Sixty complete denture wearers volunteered for the experiment. The results indicate, that the manual motor ability and the mental concentration capacity deteriorate with age, whereas the relationship of age to adaptation to new dentures and oral motor ability is less obvious. This may be due to the patient's denture experience.

Adaptation, Psychological↗
PubMed1993

Reduced, positive nitrogen balance and elevated plasma free fatty acid concentration in growing, glutamate-induced obese rats.

Glutamate-induced obesity of Wistar-rats is known to develop under normophagic and normoinsulinemic conditions, although hyperphagia and hyperinsulinemia are common to obese individuals. Rats of this obesity model show retarded growth, reduced mass of some organs, carcass and whole body as well as an extraordinary high fat content, whereas protein content is reduced. In this study, nitrogen (N) balance, urinary excretion of urea-N, ammonia-N, creatine-N and alpha-amino acid-N and plasma free fatty acid concentration of growing, glutamate-induced obese rats were determined. The main results were independent of frame of reference (mmol N/kg body mass; mmol N/kg0.75 metabolic body mass; N in % of nitrogen intake): Nitrogen intake, urinary excretion of alpha-amino acids and nitrogen excretion in faeces were equal between lean and obese rats. Nitrogen excretion in urine was elevated in obese rats, mainly resulting from increased amounts of urea and ammonia. Nitrogen balance was positive in both groups, but reduced in obese rats. These data point to normal digestion of food proteins, but an unusual high oxidative desamination rate of the absorbed amino acids in obese rats. Taking into account the various hormonal and nerval alterations in glutamate-induced obese rats, resulting e.g. in increased hepatic insulin concentration, the retained amino acid carbon should be channelled into hepatic fatty acid synthesis. Really, unfasted and overnight fasted obese rats showed elevated plasma free fatty acid concentrations. Channeling of amino acids into lipogenesis may explain the low muscle mass and striking fat accumulation--despite normophagia and peripheral normoinsulinemia--of growing, glutamate-induced obese Wistar-rats.

Amino Acids↗
PubMed1993

Total mutism--a case report of a rare psychiatric disorder and approaches for behaviour therapy.

Total mutism, which is an extremely rare psychiatric disorder, was observed in an 11-year-old boy. He refused to speak a few weeks after starting school. Behavioural analysis showed that learning by model as well as positive and negative reinforcements were involved in the pathogenesis and maintenance of the disorder. The treatment followed principles of behaviour therapy by the use of operant techniques in the sense of contingency management methods. White noise, transmitted by earphones, was utilized to interrupt auditory feedback. It has been suggested that by this method anxiety would be diminished in the case of speech phobia. Within a few months of hospital admission the boy developed speaking behaviour progressing from barely audible breaths to sibilants of normal loudness. Short dialogues were possible after 18 months. The additional conduct disorder improved simultaneously with the increase in verbal and social skills. One year after hospitalization some social uncertainty persisted with tendencies to avoid demands.

Behavior Therapy↗
PubMed1992

The two main rDNA size classes of Ascaris lumbricoides: comparison of transcription termination and spacer organization.

Structural and functional analyses were carried out to compare transcription termination and intergenic spacer organization between the two heterogeneous ribosomal DNA size classes of Ascaris lumbricoides. By performing mung bean nuclease mapping in vivo, we localized the 3' end of the mature 26S rRNA to the same position in both forms. This site coincides with the in vivo and in vitro transcription termination site of the 40S-precursor rRNA from both rDNA size classes. We demonstrate that the 3' boundary of sequences necessary for faithful transcription termination extends 35 bp beyond the end of the 26S rRNA gene and that these sequences are perfectly conserved within the two size classes. The intergenic spacers of both rDNA size classes have been completely sequenced; they are 2410 bp and 1937 bp long and show a sequence homology of 92.8%. There is no evidence for the presence of reiterated termination sites or promoters within the relatively short intergenic spacers of the two rRNA gene classes.

Animals↗
PubMed1992

How are tRNAs and mRNA arranged in the ribosome? An attempt to correlate the stereochemistry of the tRNA-mRNA interaction with constraints imposed by the ribosomal topography.

Two tRNA molecules at the ribosomal A- and P-sites, with a relatively small angle between the planes of the L-shaped molecules, can be arranged in two mutually exclusive orientations. In one (the 'R'-configuration), the T-loop of the A-site tRNA faces the D-loop of the P-site tRNA, whereas in the other (the 'S'-configuration) the D-loop of the A-site tRNA faces the T-loop of the P-site tRNA. A number of stereochemical arguments, based on the crystal structure of 'free' tRNA, favour the R-configuration. In the ribosome, the CCA-ends of the tRNA molecules are 'fixed' at the base of the central protuberance (the peptidyl transferase centre) of the 50S subunit, and the anticodon loops lie in the neck region (the decoding site) of the 30S subunit. The translocation step is essentially a rotational movement of the tRNA from the A- to the P-site, and there is convincing evidence that the A-site must be located nearest to the L7/L12 protuberance of the 50S subunit. The mRNA in the two codon-anticodon duplexes lies on the 'inside' of the 'elbows' of the tRNA molecules (in both the S-type and R-type configurations), and runs up between the two molecules from the A- to the P-site in the 3' to 5'-direction. These considerations have the consequence that in the S-configuration the mRNA in the codon-anticodon duplexes is directed towards the 50S subunit, whereas in the R-configuration it is directed towards the 30S subunit. The results of site-directed cross-linking experiments, in particular cross-links to mRNA at positions within or very close to the codons interacting with A- or P-site tRNA, favour the latter situation. This conclusion is in direct contradiction to other current models for the arrangement of mRNA and tRNA on the ribosome.

Cross-Linking Reagents↗
PubMed1992

[Acute fatty liver of pregnancy--differential diagnosis and supportive therapy].

A case of clinically diagnosed acute fatty liver of pregnancy (AFLP) is reported. Hypoglycemia and coagulopathy were predominant in the clinical course. Serial studies on blood chemistry, especially blood glucose and coagulation parameters, in association with virus serology and ultrasound, can rule out common causes of jaundice in pregnancy. This contributes to reliability of the clinical diagnosis of AFLP in the absence of liver biopsy, and ensures adequate management of the patient.

Acute Disease↗
PubMed1992

Glutamate receptor expression in the rat retina.

The expression of five genes (GluR A; B; C; D; GluR 5) encoding functional subunits of glutamate receptors was investigated in the rat retina using in situ hybridization with oligonucleotide probes. All five genes are expressed in the retina. All probes label cell bodies in the ganglion cell layer as well as somata in the inner third of the inner nuclear layer (INL), where the amacrine cells are located. In addition GluR 5, B and D, and to a lesser extent also GluR A are found in the middle and outer part of the INL, where bipolar and horizontal cells reside. Different subsets of retinal neurons may thus use glutamate receptors of different subunit composition.

Animals↗
PubMed1992

Unusual features of the retroid element PAT from the nematode Panagrellus redivivus.

The PAT retroid transposable elements differ from other retroids in that they have a 'split direct repeat' structure, i.e., and internal 300bp sequence is found repeated, about one half at each element extremity. A very abundant transcript of about 900 nt, the start of which maps to the preferentially deleted portion of PAT elements, is detected on total Panagrellus redivius RNA bearing Northern blots. A potentially corresponding ORF encodes a protein of 265 residues having a carboxy terminal Cystein motif, believed to be exclusively characteristic of the GAG protein in retoid elements. A much fainter, 1800nt long transcript, is also detected on Northern blots and maps slightly downstream of the first ORF. The predicted protein sequence of this region bears motifs typical of reverse transcriptase and RNaseH, as found in the Pol genes of retroid elements. Peptide motif similarities are greatest with the DIRS-1 element derived from Dictyostelium discoideum. The possibility of using PAT elements as transposon tagging system for Caenorhabditis elegans is discussed.

Amino Acid Sequence↗
PubMed1992

Occurrence and phenotypic properties of verotoxin producing Escherichia coli in sporadic cases of gastroenteritis.

Five verotoxin producing Escherichia coli strains were detected in 405 patients with infectious gastroenteritis and 3 such strains were detected in 11 patients with the hemolytic uremic syndrome in Switzerland. Production of verotoxin 2 was associated with the latter three strains. Four strains reacted with the probe for the virulence plasmid of Escherichia coli O157:H7, and six reacted with a recently described probe for the eae gene of enteropathogenic Escherichia coli. None of the strains was of serotype O157:H7. The methods available at present for detecting toxins or toxin genes will reliably detect all such verotoxin producing strains.

Adult↗
PubMed1992

Release signs in Parkinson's disease with and without dementia.

Release signs have been described in both age-associated diseases and in the healthy elderly. We investigated the palmomental, snout, grasp, corneomandibular and glabellar reflexes in demented and non-demented Parkinson-patients compared to Alzheimer's disease and age-matched controls. The palmomental reflex and a persisting glabellar reflex were linked to parkinsonism irrespective of dementia and were found also in Alzheimer's disease. A corneomandibular reflex was observed more frequently in demented than non-demented Parkinson-patients and in Alzheimer's disease. The snout-reflex was present in nearly all individuals irrespective of diagnosis. Thus, various release signs react quite differentially to degenerative brain disease and dementia.

Aged↗
PubMed1992

Chromatin diminution in nematode development.

Chromatin diminution in Parascaris and Ascaris represents the classical case of a developmentally programmed genome rearrangement. The process is very specific with respect to ontogenetic timing and chromosomal localization, and involves chromosomal breakage, new telomere formation and DNA degradation. Recent evidence from Ascaris lumbricoides var. suum suggests that chromatin diminution might have a function in gene regulation.

Animals↗
PubMed1992

Reactive oxygen intermediates and human immunodeficiency virus (HIV) infection.

HIV infection affects various parts of the immune system, including the CD4+ lymphocytes and mononuclear phagocytes, and causes a progressive immunodeficiency. This renders the patient susceptible to various opportunistic infections and neoplasms. Reactive oxygen intermediates (ROI) are important for the intracellular killing of microorganisms by mononuclear phagocytes and neutrophils. Although data are discrepant, several studies suggest that the generation of ROI is impaired in mononuclear phagocytes, and possibly also in neutrophils, from HIV-infected individuals. This may lead to deficient killing of intracellular microorganisms predisposing the HIV-infected patient to certain opportunistic infections. Recently, in vitro studies have shown that ROI activate the intracellular transcription factor nuclear factor kappa B (NF-kappa B) which stimulates HIV replication. Intracellular antioxidant systems, such as the glutathione system, seem to be of importance for the regulation of ROI levels and thus probably for HIV replication in vitro. However, the role of ROI in regulation of HIV replication in vivo is unknown at present. The role of ROI in HIV infection is thus difficult to assess, both at the cellular and clinical level. Reduced intracellular concentrations of ROI may lead to impaired phagocyte microbicidal functions, thus predisposing HIV-infected patients to various opportunistic infections. On the other hand, increased ROI levels may be associated with a stimulation of HIV replication leading to clinical deterioration.

HIV↗
PubMed1992

Raised serum neopterin levels in patients with primary hypogammaglobulinaemia; correlation to other immunological parameters and to clinical and histological features.

Serum neopterin levels were analysed in 43 patients with primary hypogammaglobulinaemia (25 common variable immunodeficiency (CVI), 12 congenital hypogammaglobulinaemia (CH), six X-linked hypogammaglobulinaemia (XLH)), and in 33 healthy controls. The neopterin values were correlated to lymphocyte subset counts in peripheral blood, lymphocyte mitogen responses and clinical and histological manifestations in the study group. Serum neopterin levels were significantly elevated in all subgroups of patients and particularly in the CVI groups where the highest concentrations were found (P less than 0.001, CVI versus controls). Furthermore, in CVI and CH patients elevated neopterin levels were strongly correlated to decreased number of CD4+ lymphocytes (rs = -0.61, P less than 0.005 and rs = -0.83, P less than 0.001, respectively). In the CVI group high neopterin levels were also significantly correlated to low number of circulatory B (CD19+) lymphocytes (rs = -0.58, P less than 0.05). Both patients with moderately and those with severely depressed lymphocyte mitogen responses had significantly higher neopterin levels than those with normal responses. In addition, high neopterin levels were significantly associated with the occurrence of splenomegaly and nodular intestinal lymphoid hyperplasia. The immunological findings were consistently observed in longitudinal testing, and appeared to be characteristic for the individual patient. High serum neopterin levels are thought to be a marker for hyperactivity in monocytes/macrophages, and dysfunction of these cells may therefore be associated with fundamental immune pathology in some subgroups of primary hypogammaglobulinaemia.

Adolescent↗
PubMed1992

Monoclonal antibodies specific for Clostridium difficile toxin B and their use in immunoassays.

Five mouse monoclonal antibodies (MAbs) against Clostridium difficile toxin B have been raised and characterized. Three of them were immunoglobulin M (IgM) antibodies (6B10, 6G3, and 10B9), and the other two were of the IgG1 isotype (9E5 and 17G2), recognizing specifically two distinct epitopes on the toxin B molecule. No MAb was able to neutralize cytotoxic activity significantly. The two IgG1 MAbs were purified and applied to various immunodiagnostic assays. MAbs coupled to latex beads were used for specific removal of toxin B from cytotoxic samples and for agglutination assay. An indirect sandwich enzyme-linked immunosorbent assay with MAb 9E5 or 17G2 as the capture antibody was established for identification of toxin B with a lower detection limit of 5 ng/ml.

Animals↗
PubMed1992

Nucleotide sequence of PAT, a retroid element with unusual DR organization, isolated from Panagrellus redivivus.

We have isolated several copies of the transposable element PAT of Panagrellus redivivus and sequenced one full length, presumably autonomous, 5514 bp entity. The terminal sequences are found repeated inside the element, probably representing the homologous of the long terminal repeats in common retroid elements. Two major open reading frames are present with features typical of GAG and Pol. Both the structural features and open reading frame characteristics assign PAT to the retroid family of transposable elements, and more precisely to the gypsy class of retroids when putative functional domains of Pol are compared to published sequences.

Amino Acid Sequence↗
PubMed1992

Nonspecific oral immunity in individuals with HIV infection.

Lactoferrin, lysozyme, interferon, and neopterin levels were determined in parotid saliva from 44 individuals with different clinical stages of human immunodeficiency virus (HIV) infection and 19 HIV-seronegative controls. The secretory output of individual components was calculated according to the fluid flow rate. No parotid interferon activity was found in any of the HIV-infected subjects or controls, and no significant differences in parotid lysozyme or neopterin outputs were observed. The lactoferrin output was significantly decreased in HIV-seropositive subjects in parallel with their markedly reduced parotid secretory IgA output. This combined deficiency of parotid lactoferrin and secretory IgA may well contribute to the frequent oral infections seen in subjects with HIV infection.

Adult↗