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Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 271 records · Page 15Linked to original sources
PubMed1988

Fissure sealant in permanent first molars after 10 years.

The aim of the present study was to evaluate fissure sealing of permanent teeth in children during a 10 year period. All completely erupted caries-free permanent first molars were sealed in 6 to 9 year-old children forming the patient population of one of the authors. 758 sealed fissures were controlled and followed up in the study. The fissure sealant material Delton was used and the treatments were performed according to the manufacture's recommendations. The sealings were controlled once a year and the follow-up period varied from one to 10 years. After 8 years, about 80 per cent of the sealed fissures showed total sealant retention and no caries. Another 16 per cent of the sealed occlusal surfaces showed partial retention and no caries. After 10 years only 5.7 per cent of the sealed occlusal surfaces showed caries or restorations. The results underline that fissure sealing is an effective treatment and has a low failure rate.

Adolescent↗
PubMed1988

[The production of hybrid cells producing monoclonal antibodies against Toxoplasma gondii].

Hybridomas that secrete monoclonal antibody to Toxoplasma gondii have been developed. Two groups of 10 female BALB/c mice each were immunized either over a shorter (71 d) or longer (117 d) period at first with Toxoplasma lysate antigen and afterwards with intact tachyzoites of the RH strain. Higher titres of antibody were obtained with the long-period immunization. The fusion experiments have shown that both schemes of immunization approximately result in the same number (16 and 14% respectively) of hybridoma cell lines producing antigen-specific monoclonal antibodies. Hybridoma cultures secreting antitoxoplasma monoclonal antibodies were screened parallel by indirect immunofluorescence antibody test (IFAT) and enzyme immunoassay (EIA). 16 of the hybridoma cell cultures produced positive results only in the IFAT, 112 reacted only in the EIA and 21 were positive in both tests. The monoclonal antibodies 5B10, 5G6 and 1B2, which are positive in the IFAT form a chemical compound with the major antigens on the surface of RH tachyzoites. The patterns of fluorescence produced by these monoclonal antibodies are in conformity with those produced by using polyclonal sera of Toxoplasma gondii infected hosts (mouse, rabbit, man).

Animals↗
PubMed1988

Importance of early determination of caries risk.

Even if the preventive programmes against dental disease in place today were to be highly successful there would still be individuals developing large numbers of carious lesions. It is therefore important to find methods to detect early those individuals who are prone to develop caries and then to institute special preventive programmes for them. The importance of such systems will increase when the general level of dental health improves. Then the high-caries group will require a proportionally larger part of the total dental care provided. The number of false-positive decisions will increase as the proportion of high caries risk individuals decreases. To a certain extent, this will mean that the application of specifically designed and expensive preventive programmes for predicted high-risk individuals will result in a low cost-effectiveness ratio. In a clinical study the possibility of predicting high caries risk pre-school children was analysed.

Adult↗
PubMed1988

Fluoride uptake on dry versus water-saliva wetted human enamel surfaces in vitro after topical application of a varnish (Duraphat) containing fluoride.

The uptake of fluoride was studied in vitro after application of Duraphat varnish on dry versus wetted enamel surfaces. 30 sound premolar teeth extracted for orthodontic reasons were randomly divided into three experimental groups. Duraphat varnish was topically applied for 6 hours to the air dried surfaces of ten teeth (group 1). In group 2, 10 teeth were also treated with Duraphat but the enamel surfaces were water-wetted. In group 3, surfaces were wetted with fresh chewing-stimulated human saliva. The varnish was allowed to remain on the surfaces for 6 hours in all groups whereafter all teeth stored in synthetic saliva (37 degrees C) for one week before F-analysis performed by the acid etching method. The results indicate that the F-uptake from Duraphat varnish is increased significantly by its application to dry surfaces compared to wetted surfaces. This observation may be of clinical importance and should be further investigated.

Calcium↗
PubMed1988

Caries prevalence and distribution in individuals aged 3-20 years in Jönköping, Sweden, 1973, 1978 and 1983.

In 1973, 1978, and 1983 epidemiological studies on dental health were performed in the community of Jönköping, Sweden. Each investigation covered about 500 individuals evenly distributed in the age groups 3, 5, 10, 15 and 20 years. The subjects were examined clinically and radiographically. In the present study, caries prevalence and distribution are analysed too. The total number of DFS decreased by about 50 per cent between 1973 and 1983 in all age groups. Most of the changes occurred during the period 1973-1978. The largest percentage reduction in DFS had occurred on the buccal/lingual surfaces. The number of FS-proximal showed a decrease in 1983 compared to 1973, while the number of DS-proximal was almost unchanged during the period. A closer analysis of DS-proximal revealed that there was an increase in the proportion of lesions restricted to the enamel between 1973 and 1983. In the 3 and 5-year-olds, 29 and 32 per cent of the carious lesions were restricted to the enamel in 1973 compared to 58 and 53 per cent, respectively, in 1983. For the groups of 10, 15 and 20 year-olds the numbers were 84, 84 and 78 per cent respectively in 1973, and 89, 90 and 86 per cent in 1983. A change in distribution of individuals according to DFS was found in 1978 compared to 1973. This change was still more pronounced in 1983, most of the subjects showing a low number of DFS. The results of the study show that when caries prevalence is decreasing more refined diagnostic measures should be used in order to make it possible to follow changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Caries prevalence and distribution in individuals aged 20-80 years in Jönköping, Sweden, 1973 and 1983.

In 1973 an epidemiological study was performed in the community of Jönköping, Sweden. The study covered 1000 individuals, evenly distributed in the age groups 3, 5, 10, 15, 20, 30, 40, 50, 60 and 70 years. In 1983 a new cross-sectional study was carried out on the age-groups 3-80 years. The aim of the present study was to compare and analyse in detail caries prevalence and distribution in the age-groups 20-80 years at the examinations in 1973 and 1983. The subjects were examined clinically and radiographically regarding number of teeth, caries, restorations, etc. The mean number of teeth increased between 1973 and 1983, especially in the older age-groups. During the same period, the percentage of DFS decreased in the age-groups 20, 30 and 70 years, and was unchanged in the age-groups 40 to 60 years. There were only minor differences in DS in the respective age-group during the 10-year period. The distribution of subjects according to DFS showed that a large proportion of individuals in the age-groups 20 and 30 years had low DFS in 1983 as compared to 1973. For the age-group 40-years, the distribution was unchanged. For the 50, 60 and 70-year-olds, there was a change in distribution towards a larger proportion of individuals with high DFS values in 1983 as compared to 1973. The frequency distribution of individuals with primary and secondary carious lesions respectively was skewed, a small number of individuals having a high number of lesions in each age-group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Clinical experience with bacterial contamination of Port-A-Cath systems in tumor patients].

In 33 cancer patients with subcutaneously implanted Port-A-Cath systems (Pharmacia) who developed bacteremia with rigor and high fever, aerobic and anaerobic cultures were prepared from aspirated chamber blood. Organisms were isolated from 19 patients of whom 10 had fever, but none life-threatening. In seven patients the fever was caused by infected chamber blood, while in three it was impossible to prove whether it was due to chamber contamination or the underlying disease. Almost all of the causative organisms were skin saprophytes, most frequently Staph. epidermidis, Acinetobacter Iwoffi and apathogenic Corynebacteria. The pathway of infection was probably exogenous (iatrogenic) inoculation. Removal of the catheter system was not necessary. Since strict hygienic measures were instituted when using the system no further chamber contamination has occurred.

Antineoplastic Agents↗
PubMed1987

Changes in intracellular pH and cell volume during the early phase of DMSO-induced differentiation of Friend erythroleukemia cells.

Changes in intracellular pH and water volume were measured after treatment of Friend erythroleukemia cells with 1.5% DMSO. It was found that a continuous decrease in pHi occurred, beginning 1 h after induction and a decline in pHi of 0.18 was measured after 9 h. In addition a decline in cellular water volume, of 12% only 15 min after induction, and 23% after 9 h, was observed.

Animals↗
PubMed1987

Detection and localization of a cytoplasmic domain on the beta-subunit of Na+,K+-ATPase. A monoclonal antibody study.

A monoclonal antibody directed against the beta-subunit of dog kidney Na+,K+-ATPase was generated. Immunoblots demonstrate that monoclonal antibody III 18A binds exclusively to the denaturated beta-subunit. Binding experiments with membranes and whole cells reveal that III 18A binds to membranes but not to whole cells, indicating that the antibody binds to a cytoplasmic domain on the native beta-subunit. To localize the antibody-binding epitope, purified membrane-bound enzyme was fragmented by protease treatment. Tryptic digestion yields a 30-kDa fragment of the beta-subunit, which still retains the binding capacity for the antibody. Thus III 18A probably does not bind to the NH2-terminal segment of the protein. On the other hand, fragmentation of the beta-subunit with low concentrations of papain, which is known to yield a 40-kDa NH2-terminal and a 16-kDa COOH-terminal fragment, results in a complete loss of III 18A binding. These results suggest that the antibody-binding epitope is localized at or near a papain cleavage site on the COOH-terminal part of the beta-subunit. This is inconsistent with a structure model of the beta-subunit containing only a single transmembrane hydrophobic segment with a cytoplasmic NH2-terminal portion, but agrees quite well with a hypothetical structure with four intramembrane segments.

Animals↗
PubMed1987

Endorphins are related to pain perception in coronary artery disease.

Plasma beta-endorphin levels were measured by radioimmunoassay before and after exercise in 25 patients with coronary artery disease. Eighteen patients were men and 7 were women; age range was 36 to 75 years (mean 60). All patients had angina pectoris, a positive treadmill test response or positive exercise radionuclide findings. The mean preexercise plasma endorphin level was 4.9 +/- 3.0 pmol/liter (range 0.7 to 13.5). The mean postexercise plasma endorphin level of 6.6 +/- 4.6 mol/liter (range 0 to 19.5) was significantly higher (p less than 0.05). A significant positive correlation was seen between postexercise endorphin levels and time to onset of angina (r = 0.4, p = 0.03). There were negative correlations between postexercise endorphin levels and occurrence (r = -0.4, p = 0.04) and duration of angina (r = -0.4, p = 0.05). No association was found for maximal heart rate-blood pressure product, workload, time to ST-segment depression or stress ejection fraction. A positive correlation was found between rest left ventricular ejection fraction and postexercise endorphin levels (r = 0.5, p = 0.02). In conclusion, in patients with exercise-induced myocardial ischemia, plasma beta-endorphin levels are increased after exercise; postexercise endorphin levels are related to timing and occurrence (presence or absence) of angina; and endorphins may alter the perception of pain caused by myocardial ischemia.

Adult↗
PubMed1987

Another look at the pentoxifylline efficacy data for intermittent claudication.

Porter et al have reported that pentoxifylline shows statistically significant superiority over placebo in a seven-center, double-blind, parallel group, randomized trial of outpatients with intermittent claudication secondary to chronic occlusive arterial disease. The objective of this report is convey results of the intention-to-treat population, paying careful attention to relevant methodologic issues relating to the analysis of clinical trials. At the same time, a new measure of clinical efficacy, minimum distance walked, is proposed. The rationale for this measure is discussed and results are compared with those for walking distances at each visit. The reanalysis of the Porter et al data by "intention to treat" and by use of the minimum-distance-walked measure confirms the published findings of efficacy of pentoxifylline for treatment of intermittent claudication.

Aged↗
PubMed1987

Unilateral stenosis of the vertebral artery--secondary finding with no prognostic relevance?

The outcome of 142 patients suffering from ischemic cerebral circulation disorders was followed up over a period of 33 months on average. The spontaneous course of 25 patients with unilateral, hemodynamically ineffective stenoses of the vertebral artery was compared with that of 107 patients without vertebral artery stenoses. Within the first 12 months, novel clinically manifest cerebrovascular events were observed in 16.0% of patients without vertebral artery stenosis (deaths 5.0%), but in only 4.3% of the patients with vertebral artery stenosis (no deaths). Within 30 months, only 2 of the 13 patients with vertebral artery stenosis had suffered a new cerebrovascular attack. At the end of the observation period, 39.3% of the patients without vertebral artery stenosis and 48.0% of the patients with vertebral artery stenosis were significantly disabled in their social life or had died. An additional unilateral hemodynamically irrelevant vertebral artery stenosis did not influence the rate of reinfarction or the remission of neurological deficits, independently of age, the degree of the circulatory disorder, the vascular territory involved, the presence of an organic psychosyndrome, or of additional stenoses in the carotid arteries. Consequently, a vertebral artery stenosis narrowing the vessel diameter to less than 1/3 is without prognostic relevance.

Carotid Artery Diseases↗
PubMed1987

Properties of poliovirus associated protein kinase.

Highly purified virulent poliovirus preparations harbour an endogenous protein kinase. Enzyme activity increases significantly upon purification of infectious virus particles from infected HeLa cells. Enzyme activity is stimulated by divalent cations. The substrate specificity and the degree of stimulation of the kinase are dependent on the nature of the divalent cations included in the assay. The preferred substrates for this kinase are the viral capsid proteins. Exogenously added proteins such as alpha-casein, phosvitin and protamine are also phosphorylated by the kinase. Moreover, these proteins enhance the phosphorylation of viral proteins. In the presence of Mg++ VP 2 and VP 0 are highly phosphorylated, while in the presence of Zn++ only VP 2 and VP 4, but not VP 0 or exogenous proteins are phosphorylated. Poliovirus associated protein kinase exhibits optimal activity at pH 7.9 in the presence of 10 mM Mg++. The Km for ATP is shown to be 40 microM. By testing different nucleotides as phosphate donors a specificity of the phosphorylation reaction for ATP is demonstrated. Phosphoamino acid analysis of hydrolysates of the substrates phosphorylated in the presence of Mg++ by thin layer electrochromatography and HPLC yielded phosphoserine and phosphothreonine from viral capsid proteins while hydrolysates of protamine yield only phosphoserine. Destabilization of the viral capsid, e.g. by preincubation at 42 degrees C for 20 minutes results in a stimulation of kinase activity. Moreover, phosphorylation of the poliovirus capsid proteins itself results in destabilization of the viral capsid. These findings suggest that phosphorylation of the viral coat proteins triggers or enhances the uncoating of poliovirus leading to the release of viral RNA.

Amino Acids↗
PubMed1987

Hemodynamic effects at rest and during exercise of combined alpha/beta-receptor blockade and of beta-receptor blockade alone in patients with ischemic heart disease.

The acute hemodynamic responses to beta-adrenoceptor blockade with the beta 1-selective antagonist metoprolol, and to combined alpha/beta-receptor blockade with labetalol, were compared intraindividually in a randomized single-blind, cross-over study. Fourteen patients with proved ischemic heart disease, aged 52-64 years, were studied at rest (supine) and during ischemia-inducing exercise (in the seated posture) using invasive percutaneous techniques. Metoprolol reduced heart rates and cardiac output greatly (p less than 0.001) and systemic arterial pressures slightly (p less than 0.001) under all conditions. Left ventricular filling pressures increased. Labetalol induced a slight decrease in heart rates during exercise, while cardiac output was unchanged. Systemic arterial pressures and vascular resistances, pressures and resistances in the pulmonary circulation, and left ventricular filling pressures were distinctly lower. During ischemia-inducing exercise, the differences between the effects of labetalol and metoprolol on heart rate, cardiac output, systemic vascular resistance, and left ventricular filling pressures were highly significant. The effects on the rate X pressure product and on angina were similar. It is concluded that combined alpha/beta-blockade with labetalol offsets or attenuates the potential adverse hemodynamic effects of beta-receptor blockade alone without loss of symptomatic efficacy.

Coronary Disease↗