Search PubMed⌕ Search

Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 307 records · Page 17Linked to original sources
PubMed1985

Validation of a mathematical procedure for computer analysis of flow cytometric DNA data in human tumors.

The determination of tritiated thymidine labeling index and the percentage of cells with S phase DNA content was performed on cell suspensions obtained from 69 patients with non-Hodgkin's lymphoma. The distributions of cells in the cell cycle by computer analysis of flow cytometric data were obtained by two mathematical procedures: the widely adopted Fried model and a new one proposed by Bruni et al. A significant agreement was observed by checking the Spearman index (rs) between the percentages of cells in the different cell cycle phases (G0/1, rs = 0.76; S, rs = 0.60; and G2 + M, rs = 0.43; p less than 0.001) determined by the two procedures. Similarly, a good correlation was observed between the labeling index (LI) and the S phase values obtained by the Fried (rs = 0.45, p less than 0.001) and Bruni (rs = 0.69, p less than 0.001) models, but with a higher agreement for the latter one. The S phase by the Bruni model was also superior in predicting LI: in fact, by employing the S cutoff value of 12%, a better agreement between low LI and low S phase or high LI and high S phase was observed with the Bruni procedure (90%) than with the Fried model (72%). Finally, the analysis of the prognostic significance of the different kinetic variables confirmed the prognostic relevance of LI at any time; the S phase percentage as determined by Bruni et al. was discriminant of survival only at shorter times, and no prognostic significance could be ascribed to S phase according to the Fried procedure.

Adult↗
PubMed1985

Opioid activities of human beta-casomorphins.

Opioid activities of human beta-casomorphin-4, -5, -7 and -8 and, for comparison, of the corresponding bovine beta-casomorphins were studied in the guinea-pig ileum preparation. Binding parameters, i.e. KD-values and binding site concentrations, for the interaction of human and bovine beta-casomorphins with opioid receptors in rat brain homogenates were determined in inhibition experiments, using [3H]-(D-Ala2, MePhe4, Gly-ol5)enkephalin, [3H]-(D-Ala2, D-Leu5)enkephalin and [3H]ethylketazocin as mu-, delta- and kappa-opioid receptor ligands. Analysis of binding data was performed using a non-linear curve fitting program. All beta-casomorphins examined displayed opioid activity. The affinity was highest for mu-receptors, less so for delta-receptors and lowest for kappa-receptors. It is suggested that human beta-casomorphins might play a role as "food hormones".

Animals↗
PubMed1985

The effect of extraction of infraoccluded deciduous molars: A longitudinal study.

Infraocclusion of deciduous molars is often associated with ankylosis. Such teeth are believed to be potential sites of malocclusion, with a risk of tipping of neighboring teeth and loss of space. Extraction has therefore been the most widely recommended treatment. The aim of this study was to follow longitudinally the effect of extraction versus nonextraction treatment in twenty-three homologous pairs of mandibular deciduous molars with infraocclusion when unilateral extraction was performed. The study comprised fifteen children with a mean age at the start of 10.1 years. Recordings were made at the start of the study and every 6 months thereafter until eruption of permanent successors. Periodic identical periapical radiographs and study models were taken every 6 months. Ten of the twenty-three mandibular deciduous molars on the nonextraction side showed progression of the degree of infraocclusion. All infraoccluded deciduous molars exfoliated within the normal time. There was a normal alveolar bone height on both sides after eruption of the successors. Extraction resulted in a gradually increasing space loss in fourteen of the fifteen children. In two cases a definite space deficiency at the time of eruption of the successors was registered. It has been possible to confirm very few of the previously reported negative effects following nontreatment of infraoccluded deciduous molars on exfoliation, eruption, and occlusal development in this study. The results favor a more conservative approach to extraction therapy of infraoccluded deciduous molars.

Adolescent↗
PubMed1985

Inhibition of proliferation and differentiation of mouse erythroleukemia cells by hydroxamic acids.

The effect of several hydroxamic acids on cell growth and differentiation was studied in vitro in cultures of Friend erythroleukemia cells, line F4-6. Terminal differentiation in F4-6 cells can be induced by exposure to a variety of structurally unrelated compounds or to conditions which inhibit cell growth. Hydroxamic acids do not induce erythroid differentiation but interfere with both cell growth of F4-6 cells and the induction of differentiation by DMSO in these cells. DMSO-induced terminal differentiation is inhibited even when F4-6 cells are pretreated for 24 h with hydroxamates followed by removal of the hydroxamates and transfer to fresh medium containing 1% DMSO. Reduction of cell growth by hydroxamates is completely and immediately reversible upon removal. In contrast, the inhibition of DMSO inducibility is not reversible within 24 h. Cell pretreated with hydroxamates for 24 h prior to a 96 h-exposure to DMSO show the same reduction in synthesis of hemoglobin as cells simultaneously exposed to DMSO and hydroxamates.

Animals↗
PubMed1985

Oxygen uptake and plasma catecholamines during submaximal and maximal exercise after long-term beta-receptor blockade.

Beta-receptor antagonists lower exercise heart rate and cardiac output, and can thus be expected to interfere with oxygen transport, and hence physical performance, particularly at higher levels of activity. Therefore, the effects of a 4-week and 15-month treatment period with the beta 1-selective receptor blocker acebutolol (500 mg daily) on oxygen uptake and plasma catecholamines during submaximal steady-state and maximal exercise and on maximal work load were studied in eight WHO stage 1 hypertensive men (mean age 36.4 years). Oxygen uptake, ventilation, and plasma noradrenaline, adrenaline, and dopamine concentrations during steady-state exercise were not significantly different from control conditions either after 4 weeks or after 15 months of receptor blockade, although heart rates were significantly (27% and 25%, respectively; P less than 0.01) reduced. After the 4-week treatment period, maximal oxygen uptake (3.9% reduction, NS) and maximal work load (2.4% reduction, NS) tended to be slightly lower after acebutolol compared with control values; maximal oxygen pulse was significantly (P less than 0.05) increased. However, after long-term treatment of 15 months, maximal oxygen uptake was virtually identical compared with pretreatment values, and maximal work load tended to be higher (5.2%, NS); plasma noradrenaline and adrenaline concentrations were significantly (P less than 0.05) enhanced. Since beta 1-selective receptor blockers do not affect maximal oxygen uptake and maximal work capacity after long-term treatment, they appear preferable for patients taking part in preventive and rehabilitative training programs.

Acebutolol↗
PubMed1985

Monoclonal antibodies to digoxin: comparison of in vitro and in vivo immunization.

We compared the primary response in vitro with the secondary response in vivo of A/J inbred and CD-1 outbred mice to digoxin-HSA. The frequencies of hybrid formation and growth, and of the hybridomas that secreted antibody to digoxin were similar in both strains regardless of the immunization procedure. The patterns of cross-reactivity of the monoclonal antibodies to two compounds structurally related to digoxin (ouabain and digitoxin) were likewise similar for both strains and immunization procedures.

Animals↗
PubMed1985

Production of a monoclonal antibody against an epitope on HeLa cells that is the functional poliovirus binding site.

Cell lines of primate origin carry receptors on their plasma membrane which are responsible for the specific binding of poliovirus. This paper describes the isolation and characterization of a monoclonal antibody reacting with the plasma membrane of HeLa cells. The antibody (D171) was selected for its protection of HeLa cells against the cytopathic effect of poliovirus type 1. This protection was found to extend to all three viral serotypes, while the replication of five other viruses in HeLa cells was not affected. The 125I-labelled purified antibody did not react with cell lines derived from pig, dog or rodents but bound specifically to all lines of human or primate origin. Immunoglobulin or Fab fragments of D171 prevented the binding of 35S-labelled poliovirus to HeLa cells. Conversely, nearly all binding sites of 125I-labelled D171 immunoglobulins or Fab fragments could be blocked after preincubation of HeLa cells with poliovirus. These results indicate that D171 recognizes the poliovirus receptor site on different susceptible cells and that practically all D171 binding sites are involved in the specific attachment of poliovirus to the plasma membrane. To determine whether the epitope recognized by D171 could be separated from the receptor for poliovirus, human-mouse cell hybrids were prepared and analysed. In all 40 clones tested, the susceptibility to poliovirus correlated with the binding of D171.

Animals↗
PubMed1985

Longitudinal study of dental caries in individuals in Jönköping, Sweden, aged 15 years in 1973 and 20 years in 1978.

The aim of this investigation was to study caries development between the ages of 15 and 20 yr in the same individuals. Data concerning 100 adolescents constituted the basic material. Eighty subjects could be re-examined 5 yr after the first examination. The mean number of teeth per subject was 27.1 both in 1973 and in 1978. Four subjects (4%) in 1973 and three subjects (2.4%) in 1978 showed no decayed and/or filled proximal tooth surfaces. The prevalence of intact tooth regions was higher in the mandible than in the maxilla. Only one of the 73 subjects who were free from caries in the mandibular incisor/canine region at the basic examination developed new carious lesions in this region during the next 5-yr period. Analysis of the frequency distribution of the different caries diagnostic groups revealed that 32 subjects (40%) showed no change during the 5-yr period while 47 (58.7%) now belonged to a higher caries prevalence group. 3538 (80.7%) proximal surfaces were diagnosed as intact at the basic examination. The number of intact surfaces 5 yr later was 3107 (70.9%). In individuals with low and high numbers of decayed and/or filled surfaces, respectively, there was a tendency towards a more pronounced individual caries progression in the group that showed the highest caries prevalence at the basic examination than in the group showing a low caries prevalence.

Adolescent↗
PubMed1985

Malignant teratoma of the optic nerve: case report.

An unusual case of a malignant teratoma of the right optic nerve with extension into the chiasm is presented. The preoperative diagnosis was difficult to establish. Complete removal of the lesion with postoperative irradiation was carried out. Eight months after the operation, the patient developed subarachnoid metastases by the cerebrospinal fluid pathway as well as systemic metastases and died. No local recurrence of the tumor was seen at autopsy. The therapeutic possibilities for these lesions are discussed.

Adult↗
PubMed1985

[Not Available].

Explore the source record for details and available documents.

Genetics↗
PubMed1985

[Determination of the urea content of milk in general practice].

To determine the urea in milk and thus to get information on the feeding regimen, a method using colour stripes was developped for the extension service in Bavaria. The quantitative results are fairly exact and available within four minutes comparing the colour changes of the stripe with a four-colour-scale. The scale comprises a range from 15 to more than 40 mg urea nitrogen per 100 ml of milk. The resulting colour as a rule lies between two colour shadings. Udder diseases give uncorrect results. The pH values of the milk samples should be situated between 6.6 and 6.9. This test meets the requirements of the extension service in most cases. Thus disturbances of metabolism caused by feeding can be corrected without problems and immediately. The status of lactation seems to have no influence. Most important in this respect are a feed composition adapted to ruminants and a correct ratio between intake of energy and protein.

Animal Feed↗
PubMed1985

Hereditary amelogenesis imperfecta. I. Epidemiology and clinical classification in a Swedish child population.

This study was performed in order to classify different hereditary enamel defects and to estimate their prevalence in a Swedish population. 425,000 children 3-19 years of age were screened in the Public Dental Service for suspected hereditary enamel defects in a well-defined region of Sweden. 182 of the 193 affected children were available for a thorough examination performed by one of the authors. 105 (58%) of these children could be diagnosed as Hereditary Amelogenesis Imperfecta (H.A.I.). 62 (34%) children exhibited enamel defects not related to H.A.I. and in 15 (8%) children no definite diagnosis could be made concerning H.A.I. The group of children diagnosed as H.A.I. could be classified into 12 different clinical subgroups based on two basic types, the hypoplastic and the hypomineralized. 63 of the 105 children showed the hypoplastic type of H.A.I. and 42 the hypomineralized type of H.A.I. Hypomineralized areas of the teeth were a common secondary finding in the hypoplastic type of H.A.I. Usually clinical signs of hereditary enamel defects could be identified both in the primary and in the permanent dentition. The prevalence of H.A.I. in the population studied was estimated to be 1 in 4,000.

Adolescent↗
PubMed1985

Heterozygosity in the Pi-system as a pathogenetic cofactor in chronic obstructive pulmonary disease (COPD).

A population (n = 526), consisting of employees with COPD, was compared with 2 control populations for the prevalence of Pi-phenotypes. In the patient group, the proportions of ZZ, SZ and MZ were significantly elevated. Among the patient population a prospective study was carried out to evaluate the role of alpha 1-antitrypsin deficiency as a cofactor in COPD. Severity of disease was estimated by standard pulmonary function tests, X-ray signs for emphysema and clinical assessment. Patients with ZZ, SZ and MZ were significantly worse than their MM partners. An influence of MS cannot be rejected. Phenotyping of all patients with COPD is advocated. Screening can also be by determining the ratio of alpha 1-antitrypsin and acid alpha 1-glycoprotein concentrations, which allowed detection of all ZZ, SZ, MZ and about 60% of the MS patients.

Adult↗
PubMed1985

Effect on caries of different fluoride prophylactic programs in preschool children. A two year clinical study.

376 three-year old children were divided into four experimental groups and exposed to different combinations of preventive programs for a period of two years. All the groups were given the same basic prophylactic information. Additionally Group I received fluoride tablets (FLUDENT) for daily sucking twice a day plus a placebo dentifrice free of fluoride. Group II was given a fluoride dentifrice containing 0.025% F, (ACTA). Group III was given a placebo dentifrice plus fluoride varnish (Duraphat) twice a year. Group IV a fluoride dentifrice containing 0.025% F (ACTA) plus fluoride varnish (Duraphat) twice a year. No statistically significant difference in caries increment during the two experimental years was found between the groups. A tendency to lower caries increment was found in Group IV, i.e. in the children using the low fluoride dentifrice and treated twice a year with fluoride varnish.

Child, Preschool↗
PubMed1985

Control of cell division by aphidicolin without adverse effects upon resting cells.

Aphidicolin, a tetracyclic diterpenoid obtained from the culture filtrates of Cephalosporium aphidicola and other fungi, inhibits the growth of eukaryotic cells and of certain animal viruses (SV40, Herpes and Vaccinia viruses) by selectively inhibiting the cellular replicative DNA polymerase alpha or the viral-induced DNA polymerases. The arrest of cellular or viral growth is thus due to inhibition of cellular or viral replicative DNA synthesis without interference with mitochondrial DNA synthesis, RNA, protein and nucleic acid precursors synthesis or other major metabolic pathways. The inhibition of all sensitive eukaryotic DNA polymerases by aphidicolin is competitive with respect to dCTP. Aphidicolin has thus proved extremely useful in elucidating the functional role of DNA polymerase alpha in nuclear DNA replication, of DNA polymerase gamma in mitochondrial DNA synthesis and both DNA polymerases beta and alpha in DNA repair synthesis. An important laboratory application of aphidicolin is the synchronization of the cell cycle of eukaryotic cells both in culture and in vivo. The properties of aphidicolin have recently aroused considerable interest for its possible exploitation in al practice. The mechanism of action of this drug suggests in fact that it may be useful for controlling excessive cell proliferation in patients with cancer, psoriasis or other dermatitis with little or no adverse effect upon non-multiplying cells. Interestingly, when administered to mice, the highest levels of aphidicolin are found in those tissues most actively proliferating with little or no aphidicolin present in neurons or myocardial cells.

Animals↗
PubMed1984

Alterations of 86Rb+ fluxes in poliovirus-infected HeLa cells and their dependence on virus replication.

Components of the 86Rb+ influx were investigated subsequent to poliovirus infection in the presence and absence of guanidine-HCl, both under normal steady-state conditions and after Na+ preloading of the cells. Measurements of the ouabain-sensitive 86Rb+ uptake indicated a biphasic change in the activity of the Na+, K+ pump in the course of virus infection: a transient increase in the second hour postinfection, that was detectable only after Na+ preloading and inhibition after 3 hr. The enhanced activity of the Na+, K+ pump was not affected, while the decrease later was fully prevented by the antiviral agent guanidine-HCl. The piretanide-sensitive 86Rb+ uptake due to the Na+, K+, 2 Cl- cotransport system also became strongly inhibited beginning in the second hour postinfection. The inhibition of this transport system was partially antagonized by guanidine-HCl. The remaining 86Rb+ influx in the presence of ouabain and piretanide increased in the third hour postinfection. The latter change in 86Rb+ influx, indicating an increased permeability to monovalent cations was completely abolished by guanidine-HCl.

Biological Transport, Active↗