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Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 289 records · Page 16Linked to original sources
PubMed1987

Epidemiologic study of idiopathic enamel hypomineralization in permanent teeth of Swedish children.

In the late seventies an increasing number of children showing extensive and severe idiopathic hypomineralization of the enamel of incisors and permanent first molars was reported within the Public Dental Services in Sweden. An epidemiologic study was initiated to analyze the prevalence, extension and severity in Swedish children born in 1970 and in the years before and after. 2252 children born in 1966-74 were examined according to well defined criteria on enamel hypomineralization. It was found that 15.4% of the children born in 1970 showed such changes. The corresponding figures for children born in 1966, 1969, 1971, 1972 and 1974 were 6.3, 7.3, 7.1, 5.2 and 4.4, respectively.

Adolescent↗
PubMed1987

Dental health in Icelandic urban children aged 11 and 12 years.

A total of 1370 children were examined for caries, gingivitis, periodontal pocketing, calculus and loss of marginal alveolar bone. The mean DFT and DFS scores were 6.2 and 8.7 for 11-yr-old children and 8.2 and 12.1 for 12-yr-olds. The average number of initial caries lesions was 12.4 among 11-yr-olds and 15.7 among 12-yr-olds. The proximal and smooth surfaces accounted for 37% of the total DFS score in the 11-yr-old children and 43% in the 12-yr-olds. The median DFS score for the 11-yr-old boys and girls was 7, while for the 12-yr-old boys it was 9 and for the girls 11. Only 1.8% of the children were free from caries. The occurrence of gingivitis, expressed by GBI, was 20 in both age groups. 8% of the children showed no advanced gingival inflammation, while less than 1% had bleeding gingivitis at all examined surfaces. Supragingival calculus was found in 10% of the children. Neither periodontal pocketing nor loss of marginal alveolar bone was observed.

Child↗
PubMed1987

[Tension band osteosynthesis--a method fraught with complications in surgical fracture treatment?].

Tension-band osteosynthesis is a simple and well-known procedure in the surgical treatment of fractures. An analysis of 180 patients, operated on in our hospital or admitted for corrective osteosynthesis, showed 23 mistakes of a minor degree and 20 major mistakes. Malpositioning of K-wires or cerclages caused the minor mistakes. Loosening of metal, failure of osteosynthesis or poor adaptation of fragments were responsible for the major mistakes. Tension-band osteosynthesis can only be successful if the principles of biomechanics are realised, if tension forces are transmitted by the implant, if bony buttressing is achieved by the fragments, and if torsion forces are converted into compressive forces (Pauwels).

Bone Wires↗
PubMed1987

Fluoride clearance of whole saliva in young school children after topical application.

The importance of fluoride in the saliva after topical F-application has been a matter of discussion in recent years. Therefore the aim of this study was to determine the elevation and clearance of fluoride in whole saliva in 24 seven-year-old children, 5, 30 and 120 minutes after the following topical fluoride treatments. Exp. 1: chewing F-tablets - (0.25 mg F - ACO); Exp. 2: sucking F-tablets - (0.25 mg F - Fludent); Exp. 3: F-chewing gum - (0.25 mg F - Fluomin); Exp. 4: F-mouthrinsing - (0.2% NaF); Exp. 5: F-toothpaste - (250 ppm F - ACTA); Exp. 6: F-toothpaste - (1000 ppm F); Exp. 7: F-varnish - (2.3% F - Duraphat). Statistical analysis (ANOVA) showed "the time factor" was statistically significant. The interaction between "time factor" and "treatment factor" is obvious. After F-varnish (Duraphat) and F-mouthrinsing treatment there was a significantly increased fluoride concentration in the saliva even after 120 minutes compared to the other treatments. After F-varnish treatment, the concentration in saliva two hours after application was statistically significantly higher than for the other treatments. The mouthrinsings resulted in comparison to the F-varnish in a lower F-concentration after 30 and 120 minutes which however was statistically significantly higher than the F-concentration following the other treatments. No statistical difference was found between F-applications after 30 and 120 minutes.

Analysis of Variance↗
PubMed1987

Fluorine uptake in bovine enamel from various treatment agents.

Bovine tooth enamel with a low and uniform fluorine content was used for the study of fluorine uptake by the Micro-Acid-Drop enamel biopsy technique from different treatment agents commonly used in Sweden. The fluorine concentration in the enamel was also measured after an exposure of the treated test surfaces in artificial saliva for 90 minutes. Sodium fluoride 0.2% and 2%, ferric aluminum fluoride solution and Duraphat varnish showed a high uptake of fluorine in the enamel with the highest concentration in the surface layer. Fluor Protector and the toothpastes showed a considerably lower fluorine uptake. After immersion in artificial saliva of the specimens, the concentration of fluorine in the enamel decreased.

Acid Etching, Dental↗
PubMed1986

Identification of a novel calcium-binding protein (CP22) in multidrug-resistant murine and hamster cells.

Analysis of cytoplasmic extracts of multidrug-resistant murine and hamster cells by SDS gel and 2D gel electrophoresis showed that they expressed an abundant 22 kDa protein which was absent from the drug-sensitive parent lines. SDS gel electrophoresis in the presence of EGTA and direct binding tests with 45Ca2+ showed that the resistance-associated protein is a specific calcium-binding protein. Thus the development of multidrug resistance in both colchicine-selected hamster cells and adriamycin-selected murine cells is associated with a major change in calcium metabolism. These observations provide the first molecular basis for the hypothesis that Ca2+ plays a central role in the development of the multidrug resistance phenomenon.

Animals↗
PubMed1986

Na+-dependent amino acid transport is a major factor determining the rate of (Na+,K+)-ATPase mediated cation transport in intact HeLa cells.

Little is known concerning the effects of Na+-coupled solute transport on (Na+,K+)-ATPase mediated cation pumping in the intact cell. We investigated the effect of amino acid transport and growth factor addition on the short term regulation of (Na+,K+)-ATPase cation transport in HeLa cells. The level of pump activity in the presence of amino acids or growth factors was compared to the level measured in phosphate buffered saline. These rates were further related to the maximal pump capacity, operationally defined as ouabain inhibitable 86Rb+ influx in the presence of 15 microM monensin. Of the growth factors tested, only insulin was found to moderately (22%) increase (Na+,K+)-ATPase cation transport. The major determinant of pump activity was found to be the transport of amino acids. Minimal essential medium (MEM) amino acids increased ouabain inhibitable 86Rb+ influx to a level close to that obtained with monensin, indicating that the (Na+,K+)-ATPase is operating near maximal capacity during amino acid transport. This situation may apply to tissue culture conditions and consequently measurements of (Na+,K+)-ATPase activity in buffer solutions alone may yield little information about cation pumping under culture conditions. This finding applies especially to cells having high rates of amino acid transport. Furthermore, rates of amino acid transport may be directly or indirectly involved in the long-term regulation of the number of (Na+,K+)-ATPase molecules in the plasma membrane.

Amino Acids↗
PubMed1986

Differential hemodynamic effects of beta-adrenoceptor blockers, Ca antagonists and combined alpha-beta-receptor blockade in ischemic heart disease.

The hemodynamic responses to 3 different therapeutical regimens: beta-adrenoceptor blockade, calcium inflow inhibition and combined alpha-beta-blockade were evaluated in 3 matched randomized groups of patients with ischemic heart disease and typical exercise-induced angina. The groups consisted of 22, 16 and 15 men, mean age 55-59 years. They were studied at rest and during ischemia-inducing exercise, before and after single oral doses of 100 mg metoprolol, 10 mg nifedipine and 200 mg labetalol. Pressures in the brachial artery and the pulmonary circulation were recorded by means of percutaneously introduced catheters. Cardiac output was determined according to the Fick principle. Metoprolol reduced mean arterial pressures, heart rate and cardiac output. Systemic vascular resistance and left ventricular filling pressure increased. Nifedipine resulted under all conditions in a distinct reduction of systemic vascular resistance and arterial pressures and a slight increase in heart rate and cardiac output. Left ventricular filling pressure was significantly lowered, the more the higher the initial level. The effect of labetalol was similar to that of nifedipine; however, cardiac output was unchanged and heart rate was slightly reduced. Left ventricular filling pressure was significantly lower. It is apparent that suppression of adrenergic stimulation by beta-receptor blockade alone may have adverse hemodynamic effects in ischemic heart disease and prompt further functional deterioration. Conversely, both calcium and combined alpha-beta-receptor blockade tend to improve left ventricular function by lowering both left ventricular preload and total systemic vascular resistance. The results strongly suggest that in patients in whom beta-receptor blockers appear indicated, their adverse hemodynamic effects can be offset by concomitant alpha1-receptor blockade or vasodilation without losing symptomatic efficacy. Combined alpha-beta-receptor blockade has the advantage over calcium antagonists alone to prevent any increase in adrenergic activity and related hyperkinetic response.

Adrenergic alpha-Antagonists↗
PubMed1986

Endoplasmic reticulum contains a common, abundant calcium-binding glycoprotein, endoplasmin.

The most abundant protein in microsomal membrane preparations from mammalian cells has been identified as a 100 X 10(3) Mr concanavalin A-binding glycoprotein. The glycosyl moiety of the glycoprotein is completely sensitive to endoglycosidase H, suggesting a predominantly endoplasmic reticulum localization in the cell. Using a monospecific antibody it was shown by binding and immunofluorescence studies that the glycoprotein is intracellular. Immunoelectron microscopy showed that the glycoprotein was at least 100 times more concentrated in the endoplasmic reticulum than in any other cellular organelle. It was found to be substantially overexpressed in cells and tissues rich in endoplasmic reticulum. Since it is the major common protein component associated with the endoplasmic reticulum we refer to it as endoplasmin. Calcium-binding studies show that endoplasmin is a major calcium-binding protein in cells, suggesting that at least one of its roles might be in the calcium-storage function of the endoplasmic reticulum. The amino-terminal sequence of endoplasmin is identical to that of a 100 X 10(3) Mr stress-related protein.

Animals↗
PubMed1986

Erythroid differentiation and the Na+,K+-pump in ouabain-sensitive and ouabain-resistant Friend erythroleukemia cell lines.

The selection and biochemical characterization of ouabain-resistant erythroleukemia cell lines are described. Treatment of ouabain-resistant Friend erythroleukemia cell (FLC) lines with 1 mM ouabain demonstrated a reduced ouabain-sensitive 86Rb+-uptake after Na+-preloading in comparison with ouabain-sensitive cells. The ouabain- and diuretic (piretanide)-insensitive component of the 86Rb+-uptake (residual influx) was significantly enhanced in the ouabain-resistant FLC clones. Measurements of the Na+,K+-ATPase activity (E.C. 3.6.1.3) in plasma membrane preparations of the ouabain-resistant FLC clone B6/2 indicated that a ouabain-resistant Na+,K+-ATPase activity of about 20% of the total enzyme activity existed in the presence of 1 mM ouabain. Further experiments showed that the Na+,K+-ion-gradient in ouabain-resistant B6/2 cells was unaffected by ouabain exposure whereas the gradient collapsed in wild type 12 N cells. Another property of the ouabain-resistant cell lines was a decrease of the 86Rb+-uptake due to the Na+,K+, 2Cl(-)-cotransport system measured as piretanide-sensitive 86Rb+-uptake. The data on ion transport mechanisms in QuaR and QuaS FLC are discussed with respect to mutagen-induced and spontaneous cellular ouabain resistance. In addition, the role of altered ion transport mechanisms is considered for induced erythroid differentiation.

Animals↗
PubMed1986

Oral health of individuals aged 3-80 years in Jönköping, Sweden in 1973 and 1983. I. A review of findings on dental care habits and knowledge of oral health.

The aim of the present study was to present data from dental care habits and knowledge of oral health in two cross-sectional studies carried out in 1973 and 1983. A random sample of approximately 1000 individuals evenly distributed in the age groups 3, 5, 10, 15, 20, 30, 40, 50, 60 and 70 years was studied for each of these two years. In the 1983-year examination 80 individuals 80 years of age were also included. All subjects were inhabitants of the community of Jönköping, Sweden. A questionnaire about dental care habits and knowledge was used in combination with a clinical and radiographical examination. The participants answered 23-101 questions. The same questions were raised in 1973 and 1983. For most age groups more then 80 per cent visited a dentist yearly in 1983. This yearly attendance was higher than that for 1973. In the 20-year-old group 14 per cent of the individuals received dental care in the PDS in 1973 compared to 63 per cent in 1983. The main reason to visit a dentist in 1973 was by the patient's own initiative while in 1983 the appointments were based on the dentist's initiative. The number of subjects that felt discomfort in connection with a visit to the dentist had decreased between 1973 and 1983. Knowledge about the etiology of caries had increased between 1973 and 1983 was not the case for gingivitis and periodontitis. An increase had occurred in toothbrushing frequency and the use of toothpicks and disclosing tablets but this between 1973 and 1983. In 1983, 98 to 93 per cent of the subjects in the age groups 10-30 years had been exposed to topical fluorides. The corresponding figure for 30-year-olds in 1973 was 1 per cent. It is obvious that during the period 1973 to 1983 there has been an increase in dental attendance, knowledge of dental diseases, oral health and the use of preventive measures.

Adolescent↗
PubMed1986

Periodontal ligament anaesthesia--effect on root cementum in homo.

The use of intraligamental anaesthesia has increased during recent years. Experiments performed on animals have demonstrated a certain risk for development of reversible root surface damage as a result of this method. The aim of this study was to examine histologically the effect of intraligamental anaesthesia on root surfaces in homo. The study included 26 children who, for orthodontic reasons, were to have two homologous premolars extracted from the upper jaw. The teeth were extracted at one day, one week, one month and two months after intraligament injection, and were then examined histologically. Six of 39 test surfaces exhibited root surface changes, compared to none of the 39 control surfaces. The observed changes seemed to be reversible as a reparative process could be seen after one month. The study indicated that intraligamental anaesthesia may be recommended for young individuals having a healthy periodontium.

Anesthesia, Dental↗
PubMed1986

Oral health of individuals aged 3-80 years in Jönköping, Sweden, in 1973 and 1983. II. A review of clinical and radiographic findings.

The aim of this study was to present data from clinical and radiographic examinations on oral health in two cross-sectional studies carried out in 1973 and 1983. A random sample of approximately 1000 individuals, evenly distributed in the age groups 3, 5, 10, 15, 20, 30, 40, 50, 60 and 70 years was studied for each of these two years. In the 1983-year examination 80 individuals, 80 years of age, were also included. All subjects were inhabitants of the community of Jönköping, Sweden. The clinical and radiographic examination assessed edentulousness, removable dentures, number of teeth, caries, restorations and overhangs, gingival and periodontal status, oral hygiene and calculus, endodontic treatment and periapical status. A reduction in number of edentulous individuals by 25% was recorded between the two examinations. This was matched by an increase in the mean number of teeth, mainly of molars. The largest difference in mean number of teeth between the 1973 and 1983 examinations was found for the 70-year-olds. These were 8.5 and 11.8 teeth respectively. The younger age groups showed an increase in the proportion of individuals free from caries and restorations. In 1973 the caries-free proportions were 35% for 3-year-olds and 9% for 5-year-olds. In 1983 these values had improved to 70% and 29% respectively. Corresponding to this trend the number of decayed tooth surfaces was lower in 1983. Fewer filled tooth surfaces were present 1983 compared with 1973 for the age groups 10, 15, 20 and 30 years but higher for the age groups 5, 50 and 60 years and unchanged for the remaining groups. For the younger age groups the overall reduction in DFS was about 50% but this increased to 90% for buccal and lingual surfaces. Both secondary caries and overhanging restorations had decreased in the 1983 group for all ages. At least 75-86% of restorations were without overhangs in 1983 compared to 47-65% in 1973. Gingival health had improved over the 10-year period. Sites with plaque and calculus and gingival units exhibiting gingivitis had all decreased in frequency by 1983. Buccal surfaces showed the greatest improvement. The frequency of individuals with one or more periodontal pockets (greater than or equal to 4 mm) increased with age but was of the same distribution in 1983 as in 1973.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗