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Biomedical subjects

D Muller

Publications and source records attributed to D Muller.

At least 217 records · Page 12Linked to original sources
PubMed1984

Studies of copper(II) binding to glycylglycyl-L-tyrosine-N-methyl amide, a peptide mimicking the NH2-terminal copper(II)-binding site of dog serum albumin by analytical potentiometry, spectrophotometry, CD, and NMR spectroscopy.

Unlike human serum albumin (HSA), dog serum albumin (DSA) does not possess the characteristics of the specific first binding site for Cu(II). In DSA, the important histidine residue in the third position, responsible for the Cu(II)-binding specificity in HSA, is replaced by a tyrosine residue. In order to study the influence of the tyrosine residue in the third position of DSA, a simple model of the NH2-terminal native sequence tripeptide of DSA, glycylglycyl-L-tyrosine-N-methylamide (GGTNMA) was synthesized and its Cu(II)-binding properties studied by analytical potentiometry, spectrophotometry, CD, and NMR spectroscopy. The species analysis indicated the existence of five mono-complexes at different protonation states: MHA, MA, MH-1A, MH-2A, MH-3A, and only one bis-complex MH-2A-2. The complexing ability of GGTNMA to Cu(II) was found to be weaker than that of the Cu(II) binding peptide models of HSA. The visible absorption spectra of Cu(II)-GGTNMA complexes are similar to those observed in the case of DSA-Cu(II) complexes. The weaker binding and the spectral properties of Cu(II)-GGTNMA complexes are consistent with less specific Cu(II)-binding properties of the peptide of this sequence similar to what was noted with DSA. CD results are in excellent agreement with species analysis and visible spectra where it is clearly evident that Cu(II) binds to GGTNMA starting from the alpha-NH2 group and step by step to deprotonated amide nitrogens as the pH is raised. The absence of any charge transfer band around 400 nm strongly indicates that Cu(II) does not bind to the phenolate group. Furthermore, NMR results are consistent with the noninvolvement of the tyrosine residue of GGTNMA in Cu(II) complexation. Thus, it is clear that the low Cu(II)-binding affinity of DSA is due to the genetic substitution of tyrosine for histidine at the NH2-terminal region of the protein.

Animals↗
PubMed1983

Changes in iron and transferrin levels and body temperature in experimental airborne legionellosis.

Guinea pigs were infected with either 5 or 100 cfu of Legionella pneumophila by aerosol exposure. Between two and 10 days after infection, groups of animals were killed, and their lungs and spleen were removed and cultured quantitatively. L. pneumophila multiplied in the lungs and spread to the spleen; the organisms were cleared first from the spleen and then the lungs. Significant changes were demonstrated in serum iron and transferrin levels and body temperature. The body temperature correlated directly and the serum iron concentration correlated inversely with the number of L. pneumophila recovered from the lungs but not from the spleen. These data suggest that fever and iron may restrict the growth of L. pneumophila in vivo.

Aerosols↗
PubMed1983

The influence of different immunization pathways on the immunological response in the oral mucosa.

In order to study a possible difference in the induction of local immunological responses in the oral mucosa after different immunization pathways, Wistar rats were immunized with ovalbumin by different routes, (i) via the submandibular lymph nodes, (ii) via the Peyer's patches and (iii) via the hindpad. The local reaction after antigen challenge was compared with the systemic humoral response. To study the local reaction, the homologous antigen was injected in the oral mucosa. This resulted in a delayed type hypersensitivity reaction, being the same in extent and character for all immunization pathways. The humoral response was evaluated by serum antibody production (antiovalbumine IgG). It was shown that the antibody production obtained by immunization via the Peyer's patches was significantly smaller than that in the rats immunized via other pathways. The conclusion was that the induction of a local cellular reaction was independent of the antigen pathway, whereas serum antibody production depended on the route, i.e. antigen administration via the submandibular lymph nodes and the hindpad was significantly higher than via the Peyer's patches. The possible consequences of the findings are discussed together with their relevance to immunopathological reactions in the oral cavity.

Animals↗
PubMed1982

Infection with Mycobacterium avium-intracellulare and the protective effects of Bacille Calmette-Guérin.

The protective efficacies of bacille Calmette-Guérin (BCG) and Mycobacterium avium-intracellulare (MAI) were examined in guinea pigs that were infected by the respiratory route with one of three strains of Mycobacterium tuberculosis: two strains obtained as recent sputum isolates from an ongoing BCG trial in south India and laboratory strain H37Rv. Groups of animals were given all combinations of two treatments with BCG, MAI, or placebo and than challenged. The numbers of tubercle bacilli recovered from the primary lung lesions, primary lesion-free lung lobes, and spleens were used to estimate the relative protective effects of the various treatments. In general, BCG and MAI protected equally well against the low-virulence strain of M. tuberculosis. For the two more virulent strains the results were less clear; however, a substantial protective effect of MAI compared with BCG was noted. Infection with MAI did not significantly alter the capacity of BCG to protect against tuberculous infection.

Animals↗
PubMed1981

Influence of the virulence of Mycobacterium tuberculosis on protection induced by bacille Calmette-Guérin in guinea pigs.

The protective efficacy of two bacille Calmette-Guérin (BCG) vaccines was examined in guinea pigs infected by the respiratory route with strains of Mycobacterium tuberculosis differing in virulence. Virulence was defined as the degree of tissue damage (weight) of primary lesions excised from lungs of unvaccinated guinea pigs killed 28-42 days after infection. Groups of animals vaccinated with BCG-Copenhagen (strain no. 1331), a vaccine of high potency, or those vaccinated with BCG-Prague (strain no. 725), an experimental vaccine of low potency, and groups given placebo were challenged six weeks later with one of three challenge strains differing in virulence. Protection was assessed from the difference in the number of tubercle bacilli recovered from excised primary lung lesions or from primary lesion-free lung lobes of vaccinated vs. unvaccinated animals. The virulence of the challenge strain influenced the efficacy of BCG vaccination; however, the results of other studies with a laboratory strain were in general replicated.

Animals↗
PubMed1981

Influence of vaccination-challenge interval on the protective efficacy of bacille Calmette-Guérin against low-virulence Mycobacterium tuberculosis.

The influence of vaccination-infection interval on protection induced by bacille Calmette-Guérin (BCG) was studied in an animal model of experimental airborne tuberculosis. Guinea pigs were simultaneously skin-tested with mammalian tuberculin and intracellularin and vaccinated with BCG-Copenhagen (strain no. 1331). At weekly intervals thereafter, groups of animals were infected by the respiratory route with about five viable units of a recently isolated strain of Mycobacterium tuberculosis of low virulence. The animals were necropsied six weeks after challenge, and tubercle bacilli recovered from primary lung lesions, primary lesion-free lung lobes, and spleens were counted. Protection was defined as a significant reduction in the number of bacilli recovered from the tissues of vaccinated as compared with unvaccinated animals. The data obtained for two of the three tissues indicated that BCG-Copenhagen induced a significant level of protection against this low-virulence of M. tuberculosis.

Animals↗
PubMed1980

The role of nutritional status, airway obstruction, hypoxia, and abnormalities in serum lipid composition in limiting exercise tolerance in children with cystic fibrosis.

Previous work has shown that impaired exercise tolerance in children with cystic fibrosis (C.F.) is related to the severity of airway obstruction without elucidating the possible roles of hypoxia or malnutrition. It has been suggested that poor nutrition leads to abnormalities in serum fatty acids composition, which may lead to tissue hypoxia. We investigated the roles of hypoxia, pulmonary mechanics, nutritional status, and serum fatty acid composition in limiting exercise tolerance in C.F. In 20 children with C.F., exercise tolerance, while breathing air and while breathing oxygen, was evaluated on a cycle ergometer and compared to pulmonary function tests, anthropometric data, serum lipid compostition, and clinical condition. The mean percent work expected from height (Wmax) was 75, and was unchanged by O2. Wmax correlated significantly with the degree of respiratory impairement, the discrepancy between height and weight, and the clinical score but not serum fatty acid composition. Where measured, no child at any time had an elevated end tidal CO2(PetCO2). We conclude that nutritional status and airway obstruction are closely correlated with exercise tolerance in C.F. and that, unlike the case in adults with chronic obstructive pulmonary disease, exercise-limiting dyspnea occurs in the presence of a normal PetCO2.

Adolescent↗
PubMed1980

Hand, body and viewing behaviors of students with high or low self-concepts.

Eight junior high school students with low scores on peer-relations self-concept and self-esteem scales and eight with high scores were video taped in a choral music classroom. Hand, body, and viewing behaviors occurring on the tapes were analyzed. During non-instructional free time, the low scorers touched themselves more frequently than did the high scorers. No other significant differences in the behaviors of the two groups were detected.

Adolescent↗
PubMed1979

Medium for selective isolation of Fusobacterium nucleatum from human periodontal pockets.

A selective medium, CVE agar, was developed for the isolation of Fusobacterium nucleatum from subgingival plaque of periodontally diseased patients. The medium contained 1.0% Trypticase (BBL Microbiology Systems), 0.5% yeast extract, 0.5% NaCl, 0.2% glucose, 0.02% L-tryptophan, 1.5% agar, and 5% defibrinated whole sheep blood. Erythromycin and crystal violet were added as the selective inhibitory agents at concentrations of 4 and 5 micrograms/ml, respectively. The medium permitted almost total recovery of F. nucleatum when compared with a nonselective medium and suppressed the recovery of most remaining species by nonselective medium and suppressed the recovery of most remaining species by 6 to 8 orders of magnitude. Microorganisms suppressed to a lesser degree included Selenomonas sputigena, Actinobacillus actinomycetemcomitans, Eikenella corrodens, and some strains of Peptostreptococcus. The distinct colonial morphology of F. nucleatum on CVE agar made differentiation relatively easy when contaminants were present. With this medium, F. nucleatum was enumerated from 278 subgingival plaque samples and accounted for less than 1.0 to greater than 25% of the cultivatable microbiota.

Adolescent↗
PubMed1978

Relationships between self-concept, self-esteem, popularity, and social judgments of junior high school students.

This study examined the relationship between social self-concept and popularity for 93 male and female seventh, eighth, and ninth graders. It also assessed ability to make accurate social judgments and social self-esteem as a function of self-concept. The results revealed a moderate relationship (r = .29) between self-concept and popularity. No evidence was found to suggest that either self-esteem or ability to make accurate social judgments was related to accuracy of self-concept.

Adolescent↗
PubMed1977

Short-stay surgery for inguinal hernia. Clinical outcome of the Shouldice operation.

In 1970 a general surgical team on Teesside adopted the Shouldice operation for inguinal hernia together with a policy of short-stay surgery. Careful follow-up has established that repairs using the suture material of choice--stainless-steel wire--have an estimated 6-year recurrence-rate of 0.8%, statistically indistinguishable from that achieved by the highly specialised Shouldice Clinic. However, the recurrence-rate 2 years after suturing with an alternative polyester-based material is estimated at 8.1%--a figure much more in keeping with rates reported by general surgeons using traditional methods.

Adult↗
PubMed1977

Academic achievement as a function of specific and global measures of self-concept.

This study examined the correlations between academic achievement and factor specific, as well as global, measures of self-concept for 314 fourth and sixth grade boys and girls divided into grade level groups with and without Spanish surnames. The Primary Self-Concept Inventory was used to measure self-concept on six scales: physical size, emotional state, peer acceptance, helpfulness, success, and student-self. A global self-concept score was derived by totaling the scores on the six scales. Achievement was measured as total score on the Comprehensive Tests of Basic Skills. The two specific measures of self-concept that were most reflective of school performance, success and student-self, tended to show low positive correlations with achievement. The remaining specific measures, as well as the global measure, tended to show no relationship to achievement. These results suggest that an area specific model of self-concept is more useful than a global or undifferentiated model. Further, the low correlations between school related self-concept and achievement suggest that, as a group, students frequently have rather inaccurate academic self-concepts.

Achievement↗
PubMed1977

The effect of altering self-descriptive behavior on self-concept and classroom behavior.

This research examined the impact of operant reinforcement of positive self-descriptive behavior on the self-concepts and classroom behavior of 60 fifth-grade students. Three groups of 10 male and 10 female low self-concept students wrote a series of eight essays describing their school performance. The first group (P) received written reinforcement for positive self-descriptions of their school performance. The second group (G) received an equal number of reinforcements for general statements. The third group (C) received no reinforcement for written statements. Three areas of self-concept were measured with the Primary Self-Concept Inventory: personal-self, social-self, and intellectual-self. A frequency count was also made of nine classroom behaviors thought to be influenced by self-concept. The P group displayed increases in the frequency of positive self-descriptive statement and in intellectual self-concept but no changes in personal self-concept, social self-concept, or the nine classroom behaviors. The G and C groups showed no change in self-description, self-concept, or the nine classroom behaviors.

Achievement↗
PubMed1977

Individualized, success oriented instructions in achievement and self-concept of first graders.

Gains in achievement and self-concept of 23 first graders receiving individualized, supportive, success-emphasizing instruction were compared with those of 22 receiving more traditional instruction. The individualized group showed greater gains in certain academic skills but no greater gain in self-concept. This study did not support the contention that a supportive, success-emphasizing classroom environment enhances self-concept.

Achievement↗
PubMed1977

Relationships between area-specific measures of self-concept, self-esteem and academic achievement for junior high school students.

Physical maturity, peer relations, academic success and school adaptiveness self-concept and self-esteem measures were correlated with reading, language, mathematics, and composite achievement scores for 26 male and 48 female junior high school students. Academic success self-concept was significantly correlated with each of the achievement measures. Peer relations self-concept and self-esteem correlated with language, math, and composite achievement. Academic success self-esteem measures did not correlate with any of the measures of achievement.

Achievement↗
PubMed1976

The effects of experimentally induced changes in self-concept on associative learning.

It has been hypothesized that self-concept influences ability to learn. This experiment systematically manipulated the self-concepts of learners regarding their abilities to learn a foreign language and measured their subsequent learning of a synthetic foreign language vocabulary list. Eleven Ss were randomly assigned to each of three groups: self-concept raised, self-concept lowered, control. Ss were college freshman who were not enrolled in a foreign language course or had not previously taken more than one semester of a foreign language. Self-concepts were measured as self-description of ability to learn a foreign language. Self-concepts were raised or lowered by providing false scores on a foreign language aptitude test. Learning was measured as performance on a paired-associates task utilizing random shapes and CVCs. Ss with lowered self-concepts learned more slowly than control Ss or Ss with raised self-concepts.

Achievement↗