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Biomedical subjects

A Johansson

Publications and source records attributed to A Johansson.

At least 199 records · Page 11Linked to original sources
PubMed1995

Craniofacial morphology, occlusal traits, and bite force in persons with advanced occlusal tooth wear.

The aim of this study was to investigate the dentofacial structure, the occlusal traits, and the bite force in subjects with advanced occlusal wear. The material comprised 54 adults, 30 men (mean = 40 years, range 16 to 61) and 24 women (mean = 28 years, range 18 to 47), most of whom had a full or near-full complement of natural teeth, and the presence of occlusal wear. Craniofacial structure was studied on lateral cephalograms. Occlusal traits were examined on study casts, these serving also for an evaluation of occlusal wear to be carried out by using an ordinal scale. Bite forces were recorded at differing force levels (maximum biting, "biting as when chewing" and "light biting") and occlusal positions. Although maximum bite force and endurance time did not differ significantly between men and women, the level of bite force was high compared with other samples. The craniofacial structure of the sample was characterized by a deviation in the vertical direction, a small angle between the mandibular-palatal planes and a small gonial angle, as compared with Swedish adult norms. No significant differences were found in anteroposterior relationships between persons with advanced wear and normal standards. The results support the hypothesis that functional hyperactivity of the masticatory system imposed increased stress on the bony structures of the craniofacial complex with possible influences on its structure.

Adolescent↗
PubMed1995

Prevalence of signs and symptoms of temporomandibular disorders in a young male Saudi population.

The aim of the present study was to investigate the prevalence of temporomandibular disorders (TMD) in a selected young male Saudi population. The material comprised 105 dental students having a mean age of 23 years within the range of 20-29 years. A functional evaluation of the stomatognathic system was performed using the Helkimo anamnestic and clinical dysfunction index. Almost two-thirds of the individuals had no signs and symptoms of TMD. Thirty per cent of the individuals reported mild dysfunction (Ai I) and 6% had severe symptoms (Ai II). Thirty-three per cent showed mild clinical signs of dysfunction (Di I) and 3% had signs of moderate dysfunction (Di II). Only 1% exhibited severe clinical signs (Di III). While the individuals represented a non-Western population, the prevalence of signs and symptoms of temporomandibular disorders compared favourably to that found in Western countries, at least as regards to reported symptoms.

Adult↗
PubMed1995

Long-term local corticosteroid application does not influence nerve transmission or structure.

The long-term effects of a locally applied depot form of a corticosteroid on the electrical properties and structure of nerves were investigated in an animal experimental model. The conduction in electrically stimulated A-fibres of the plantar nerve was monitored by a bipolar volley recording of the sciatic nerve whereas the conduction in C-fibres of the plantar nerve was measured through a C-fibre evoked segmental flexion reflex in the anaesthetized rat. Droplets of either methylprednisolone acetate or vehicle were placed under direct observation on the plantar nerve. Saline was used as a control on the contralateral side. One to two weeks after the application both the A-fibre volley of the sciatic nerve and the C-fibre evoked reflex discharge of flexor motoneurons were recorded. No difference was found between the nerves treated with corticosteroid, constituent vehicle or saline. Light and electron microscopic analysis of the nerves showed no changes in the nerve fibres or in the intraneural connective tissue in either the corticosteroid treated or the control nerves. It is concluded that locally applied corticosteroids in limited amounts have no long-term effects on the electrical and structural properties of peripheral nerves.

Administration, Topical↗
PubMed1995

Concomitant single-dose and multiple-dose pharmacokinetics of terodiline in man, with a note on its enantiomers and major metabolites.

Single-dose and multiple-dose pharmacokinetics of terodiline were studied in 20 healthy volunteers by giving an initial oral dose of deuterium-labelled terodiline (12.5 mg or 25 mg) followed by multiple doses of Mictrol tablets (12.5 mg b.i.d. for 14 days and 25 mg b.i.d. for 14 days or vice versa). The enantiomer serum concentration ratio of S(-)/R(+) terodiline was close to unity at steady-state as well as during the disposition phase. The average single-dose kinetic parameters for the racemate after the 12.5 mg dose were: maximum serum concentration 41 micrograms/l, the corresponding time 3.4 hr, terminal half-life 61 hr, oral clearance 77 ml/min., renal clearance 12 ml/min. and apparent volume of distribution 382 1. The single-dose kinetics for the 25 mg dose and the multiple-dose kinetic parameters showed that linear kinetics prevailed. The average steady-state serum concentration was 275 micrograms/l at the lower dose and 509 micrograms/l at the higher dose. The degree of fluctuation during a dosage interval was 19% and the time to steady-state was about 9 days. The fraction unbound was about 8%. Unconjugated p-hydroxylated terodiline, p-hydroxy-m-methoxyterodiline and hydroxy-tert-butyl-terodiline constituted 15%, < 1% and 5%, respectively, of the terodiline steady-state levels.

Adult↗
PubMed1995

Antimicrobial screening of zinc in the absence or presence of oleoresins and various resin acids.

Zinc and oleoresins are the main components of several wound dressings, and are also frequently used in root canal treatment. The in vitro antibacterial effects of zinc, six highly purified resin acids and two commercial oleoresins alone or combined in varying proportions were analysed. Oleoresins are composed of approximately 90% resin acids and the most common acids were included in this study. The antibacterial activity of the various chemicals was estimated using a Bioscreen robot analyser, which allowed 24 h kinetic documentation of bacterial growth. The bacteria employed were reference species commonly occurring on human skin or of oral origin. Zinc as well as the oleoresins and the pure resin acids all showed antibacterial activity when present in growth media, but the sensitivity of the bacteria varied. The presence of resin acids and oleoresins increased the antibacterial effect of zinc to varying degrees depending on the combination and the bacterial species tested. The results of the present study indicate that zinc, resin acids, or oleoresins alone, as well as combined, show antibacterial activity against selected aerobic Gram-positive and anaerobic Gram-negative bacteria.

Abietanes↗
PubMed1995

Different functional and morphological characteristics in a nonadherent subpopulation of human macrophages recovered by bronchoalveolar lavage.

The alveolar macrophages (AMs) constitute a morphologically and functionally heterogenous cell population. The adhesive properties of these cells are important for their role in host defence. To focus on the heterogeneity, a population of nonadherent macrophages were characterized functionally and morphologically. These cells were then compared with the total alveolar macrophage population. Alveolar cells (> 95% alveolar macrophages), were recovered by bronchoalveolar lavage (BAL) from healthy smokers. Nonadherent macrophages were separated by adhesion. The phagocytic capacity and the autofluorescent properties of the cell populations were determined in flow cytofluorometric assays. In addition, electron microscopic evaluation was performed. The alveolar macrophage adhesion to wells coated with albumin increased in a time-dependent manner. After 15 min, median 47%, interquartile range 42-52% (uncoated wells 68%, 67-72%) of the alveolar macrophages were attached; and after 60 min, 56%, 51-58% (uncoated wells 73%, 71-76%) of the alveolar macrophages were attached. The nonadherent alveolar macrophage population had less phagocytic capacity. The cell autofluorescence increased with increasing cell size and cell complexity/granularity in both populations. The nonadherent cells were more autofluorescent, indicating an increased granularity/complexity. These findings were confirmed with electron microscopy. Thus, the nonadherent alveolar macrophages had more cytoplasmic inclusions than the total alveolar macrophage population (volume density median 0.39, interquartile range 0.35-0.46 and 0.31, 0.26-0.34, respectively), but less surface protusions. We conclude that in lavage fluid from human smokers there is an ultrastructurally specific subpopulation of alveolar macrophages, showing less adhesive properties and impaired phagocytic capacity in vitro. These macrophages may be older alveolar cells or, alternatively, airway macrophages. Since only alveolar macrophages from smokers were investigated, we cannot draw any conclusions regarding alveolar cells from nonsmokers. Nevertheless, the heterogeneity of the lavaged cells should be taken into consideration when the functional ability of the alveolar macrophages are evaluated.

Adult↗
PubMed1994

Neutrophil control of formylmethionyl-leucyl-phenylalanine induced mobilization of secretory vesicles and NADPH-oxidase activation: effect of an association of the ligand-receptor complex to the cytoskeleton.

The stimulus formylmethionyl-leucyl-phenylalanine (FMLP) interacts with neutrophils and generates signal(s) in the cells that induces mobilization of the secretory vesicles as well as activation of the superoxide anion/hydrogen peroxide generating NADPH-oxidase. Binding, at 15 degrees C, of FMLP to its neutrophil surface receptor is followed by an association of the ligand-receptor complex to the cell cytoskeleton, and this association occurs concomitant with a desensitization of the cells with respect to activation of the NADPH-oxidase. Other stimuli can still activate the oxidase (in fact even induce a primed response), indicating that the observed phenomenon is stimulus specific and could not be accounted for by an effect on the oxidase itself, but rather that the association of the ligand-receptor complex to the cytoskeleton eliminates the capacity of the complex to generate the signal(s) that activates the NADPH-oxidase. The cytoskeleton associated ligand-receptor complex generates, however, the signal(s) responsible for mobilization of the secretory vesicles, to the plasma membrane, and this mobilization occurs without any increase in the intracellular concentration of free Ca2+.

Calcium↗
PubMed1994

Effects of spermidine on function and ultrastructure of alveolar macrophages.

It is known that spermidine and other naturally occurring polyamines accumulate in rat lung slices by an energy-dependent uptake process and that alveolar macrophages (AM) have a greater rate of uptake than has the total lung cell population. In the present study rat AMs were incubated with spermidine, which resulted in a marked and significant (P < 0.002) decrease in phagocytosis of heat-killed yeast cells at concentrations 0.2 and 0.5 mM and a tendency to decrease at 0.05 mM. The number of microtubules surrounding the centrioles was measured using electron microscopy and appeared to be decreased at concentrations 0.2 and 0.5 mM. There was no affect on phagolysosomal pH. The results suggest that spermidine might affect the defense against inhaled pollutants and microbes, especially when spermidine levels are increased, as they are under conditions with high mitotic activity, e.g., in tumors.

Animals↗
PubMed1994

Lateral and protrusive contact schemes and occlusal wear: a correlational study in a young adult Saudi population.

This study investigated the influence of occlusal contacts on the location and severity of occlusal wear during various mandibular movements. The study population consisted of 80 dental students with a mean age of 22 years, within the age range of 19 to 25 years. A dentition wear index--in addition to anterior, canine, and posterior subindexes--was derived from a tooth-by-tooth evaluation of casts. Lateral excursive and protrusive contact relationships were obtained by clinical examination. There was no correlation between the distribution of occlusal wear and the type of lateral excursive contact scheme. The location of contacts in protrusive movement demonstrated a distinct correlation with occlusal wear in overall severity and distribution according to segmental wear subindexes. The results indicate that the role of "disclusive protection" in the occurrence of occlusal wear may be questioned; the efficacy of "mutual protection" is similarly unsubstantiated, and the results lend further support to the concept of multifactorial etiology of occlusal tooth wear.

Adult↗
PubMed1994

Cytotoxicity in bacterial cultures: interaction and cell-specificity, possible factors in periodontal disease.

Cytotoxicity in culture media of various growing bacterial strains was estimated by Cr-51 release of labelled target-cells. Interaction studies were made by adding each of the different UV-killed bacteria to the medium with viable bacteria. The reference oral bacterial strains were: Actinobacillus actinomycetemcomitans Y4, Porphyromonas gingivalis, Fusobacterium nucleatum and Streptococcus mitis, which were compared with the reference bacteria Staphylococcus aureus 209 and Staphylococcus epidermidis. The target cells were: gingival fibroblasts (GF), periodontal membrane fibroblasts (PMF), pulpal fibroblasts (PF), HeLa-cells (HeLa), and lymphoid neoplasm cells (LN). Synergistic, as well as antagonistic, effects on target cells were observed. The cytotoxicity of A. actinomycetemcomitans in presence of P. gingivalis is neutralized while in presence of S. aureus it was increased. Bacterial interactions with F. nucleatum and P. gingivalis cytotoxicity were observed. The cytotoxicity of F. nucleatum was increased when cultured together with A. actinomycetemcomitans. Each cell type reacted differently to the toxicity of the supernatant of growth medium in which the same bacterial strain had been cultivated, which indicates cell specificity of the toxins.

Aggregatibacter actinomycetemcomitans↗
PubMed1994

Phagolysosomal pH in alveolar macrophages from smokers and non-smokers.

1. Alveolar macrophages efficiently phagocytize particles deposited in the alveolar part of the lung. Phagolysosomal pH in alveolar macrophages from rabbits, dogs, baboons and guinea pigs is around 5 pH units. A low pH is of importance for clearance of inorganic particles and probably also for defence against bacteria and fungi. 2. Phagolysosomal pH in alveolar macrophages from smokers and non-smokers was measured using fluorescein-conjugated amorphous silica particles as a probe. pH was the same in both groups and similar to earlier studies on alveolar macrophages from animals. 3. The morphological picture between alveolar macrophages from smokers and non-smokers differed clearly with a high number of dense inclusions of great variation in size and shape in macrophages from smokers. Ingested test particles were located in all types of inclusions. 4. We conclude that phagolysosomal pH in human alveolar macrophages is similar to that in several animal species and that it is rather insensitive to influence from the environment.

Adult↗
PubMed1994

Prevalence of occlusal tooth wear and its relationship to lateral and protrusive contact schemes in a young adult Indian population.

The aim of the present study was to investigate the prevalence and severity of occlusal tooth wear and their interrelationships with lateral and protrusive occlusal contact schemes in a young adult Indian population. The material comprised 64 individuals (age: mean = 19 years; range, 17-24 years). Assessment of wear was performed by means of a tooth-by-tooth evaluation of casts. Lateral excursive and protrusive contact relationships were recorded at the clinical examination. There was no difference in the degree of wear between women and men. Mean occlusal wear was low for the population studied compared with similarly aged Scandinavians and Saudis. No differences in the severity of wear were found in relation to lateral excursive and protrusive contact schemes. Whereas the low wear experience in the present Indian sample may be related to dietary factors, more must be understood about the various other causes of occlusal tooth wear before its functional interdependence becomes clear.

Adolescent↗
PubMed1994

Traumatic hip dislocation with spontaneous reduction and capsular interposition. A report of 2 children.

We present 2 cases of posterolateral hip dislocation in children followed by spontaneous reduction and interposition of soft tissue. After reduction of a dislocated hip joint, interposition of soft tissues or fracture fragments must be excluded. When reduction has occurred spontaneously, the condition may be misjudged, correct treatment delayed and the hip joint permanently damaged, as occurred in one of our cases. In the second case, prompt surgery was undertaken and the patient recovered completely.

Child↗
PubMed1994

Bacterial interference in vitro. Comparison between a quantitative kinetic and a cocultivation blood agar test method.

The aim of the present study was to compare two methods for estimation of bacterial growth interference between various bacteria using a Bioscreen robot analyzer, allowing kinetic documentation, and a cocultivation test on blood agar plates. Six laboratory strains with different virulence and growth requirements were used: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mitis, Staphylococcus aureus, and Staphylococcus epidermidis. The interference activity was correlated with a reference system of Streptococcus sanguis (strain alpha 89) and Streptococcus pyogenes (group A streptococci, GAS serotypes T 9 and T 22). The methods used and results obtained were as follows: 1. Estimation of synergistic and antagonistic bacterial interferences using a Bioscreen robot analyzer. Suspensions of viable bacteria were added to microtiter plates with different concentrations of UV light-killed bacteria in liquid media. The Bioscreen analyzer monitored bacterial growth every 10 min for 24 h giving kinetic data during the growth period. Synergisms as well as antagonisms were demonstrated between the tested bacterial strains which have not earlier been reported in the literature. However, the antagonistic effect observed between the six strains was less than that induced by the S. sanguis strain on the two strains of S. pyogenes. 2. Cocultivation of bacterial strains on blood agar surface with precultivated or simultaneously stamped interfering bacteria indicated no detectable interference between the six tested bacterial strains, while the S. sanguis strain inhibited the growth of S. pyogenes strains as well as the hemolysis around the colonies. The Bioscreen method was found more sensitive for testing bacterial interference compared to the commonly used blood agar test.

Bacteria↗