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Biomedical subjects

H Krug

Publications and source records attributed to H Krug.

At least 37 records · Page 2Linked to original sources
PubMed1989

Progressive ankylosis (ank/ank) in mice: an animal model of spondyloarthropathy. II. Light and electron microscopic findings.

Murine progressive ankylosis was studied by light and electron microscopy (EM). By light microscopy, the earliest synovial lesion was inflammatory followed by synovial proliferation and cartilage erosions. Later changes included progressive joint ankylosis by fibrosis and ossification of articular and periarticular tissues and new bone proliferation. By EM, synovial cell proliferation and hypertrophy with collagen deposition was seen before the appearance of intracellular and extracellular hydroxyapatite crystals. These pathologic changes are the same as those found in the human spondyloarthropathies. Our EM findings demonstrate that hydroxyapatite crystals appear in the joints of ank/ank mice after the initial inflammatory phase.

Animals↗
PubMed1989

Cytophotometric and interference microscopic investigations in carcinomas of the oral cavity.

The DNA content and the nuclear dry mass of 18 keratinized squamous cell carcinomas and their metastases, of one adamantinoma recurrence and two adenoid cystic carcinomas of the oral cavity were determined in comparison to the normal buccal mucosa using Feulgen scanning cytophotometry and interference microscopy. The squamous cell carcinomas could be classified into five groups based on their DNA distribution pattern. The nuclear dry mass and its variation were found to be different from the normal mucosal epithelial cells in all cases. No differences could be found between diploid cells and cells of a higher degree of ploidy. Therefore the relation of nuclear dry mass and DNA content appeared to be lower in cells of higher DNA ploidy. This fact is discussed in relation to the underlying molecular biological processes. This leads to the conclusion that the increase of the nuclear dry mass (mainly protein) precedes the increase of the DNA content. The combined measurement of DNA content and nuclear dry mass allows a better characterization of malignancy than each of the nuclear components measured alone. The difference of nuclear dry mass between malignant cells and normal mucosal epithelial cells is more sensitive than the deviation of the DNA content owing to the fact that malignant tumours with normal DNA content exist.

Carcinoma, Squamous Cell↗
PubMed1989

[Age changes of functional nuclear swelling and classes of nuclei in human hepatocytes].

The aim of the study was to describe aging changes in the functional nuclear edema and the classification of human hepatocyte nuclei, by determining three parameters--the size of the nucleus, the relative DNA quantity and the number of chromocenters. For this purpose, karyometry and DNA cytophotometry were performed on 10 human liver preparations. The data obtained was subjected to correlation, cluster and discriminance analysis. The results indicated a reduction in the capacity of liver cells for functional nuclear edema as aging progressed. Whereas at a young age there is only a loose correlation between nuclear size and DNA content, it becomes much stricter later on, partly caused by polyploidization. Cluster analysis, followed by discriminance analysis, is well suited for dividing the nuclei of human hepatocytes into two or three statistical populations provided the nuclear area, DNA quantity and number of chromocenters are all used as characteristics simultaneously. When allowance is made for functional edema, the biological interpretation of clusters from young liver preparations permits meaningful conclusions, but it appears problematic for old preparations. Here it might be more practical to analyze the mixed distributions resulting from a determination of the DNA quantity or nuclear size alone.

Aging↗
PubMed1988

Progressive ankylosis in mice. An animal model of spondylarthropathy. I. Clinical and radiographic findings.

To determine its similarity to human spondylarthropathies, we studied murine progressive ankylosis, a spontaneously occurring disorder of joints in mice. Clinically, peripheral joints were inflamed initially, then became ankylosed in a predictable sequence from distal to proximal. Forefeet were involved before hindfeet. Axial joint involvement produced severe spinal ankylosis. Extraarticular manifestations included balanitis and crusting skin lesions. Radiographically, bony erosions and calcification of articular and periarticular tissues were extensive, and vertebral syndesmophytes produced a "bamboo" spine. We conclude that progressive ankylosis is a systemic disease with many clinical and radiographic similarities to human spondylarthropathies, and it may represent a useful animal model for the study of the human diseases.

Animals↗
PubMed1988

Flow cytometric DNA histograms and type of growth.

DNA histograms of human tumors should be interpreted together with the type of growth. In order to prove this connection the Ehrlich ascites tumors of 144 mice were investigated by absolute cell counting and flow cytometry. The exponential, transition and steady-state phases of tumor development were defined as types of growth based on the logistic function (Verhulst-Pearl). Flow-cytometric histograms (ethidium-bromide, olivomycin) were evaluated by two methods presupposing lognormal distribution and resulting in the same trend of changes concerning the percentage of cells in the three cell-cycle phases. In exponential growth the histograms show a high S-phase compartment and a decrease of the G2M peak. The increased percentage of S-phase cells is caused by a recruitment from G0-1 and G0-2 after transplantation. The decrease of the G2M peak is due to the exponential growth, a recruitment from G0-2 and a relative shortening of G2M duration. A high G2M peak and a low S-phase portion occur in steady state. Besides a decrease of DNA-synthesizing cells the S compartment decreases as a result of a relative S-phase shortening. For the increase of the G2M peak, transition into steady state, prolongation of G2M duration, recruitment of G0-1 and the occurrence of G0-2 cells are responsible. The same histogram may reflect different biological behavior patterns depending on the type of growth.

Animals↗
PubMed1987

Stimulation of arachidonic acid metabolism via phospholipase A2 by triethyl lead.

Human blood platelet aggregation and the formation of icosanoids were studied in response to triethyl lead chloride (Et3PbCl). Concentrations higher than 75 microM stimulate platelets to aggregate, whereas low concentrations (less than or equal to 20 microM) caused platelet hypersensitivity to aggregating agents such as collagen or arachidonic acid. Incubation of suspensions of washed platelets with Et3PbCl resulted in a stimulated liberation and subsequent metabolism of arachidonic acid. This response was dependent on the concentration of Et3PbCl and the incubation time. Using low concentrations of Et3PbCl and up to 3 h of incubation, the lipoxygenase product 12-hydroxy-5,8,10,14-icosatetraenoic acid was the major metabolite. Under normal conditions, however, stimulation of platelets with collagen, thrombin, or arachidonic acid leads to higher amounts of the cyclooxygenase products 12-hydroxy-5,8,10-heptadecatrienoic acid and thromboxane B2. The aggregation of human platelets induced by Et3PbCl was inhibited by three different drugs: acetylsalicylic acid, forskolin and quinacrine; but only quinacrine could prevent the liberation of arachidonic acid and the appearance of its metabolites. These specific effects of the inhibitors on Et3PbCl-stimulated platelets as well as the differences in the pattern of arachidonic acid metabolites and phosphatidic acid suggest a direct stimulatory action of Et3PbCl on platelet phospholipase A2.

Arachidonic Acid↗
PubMed1987

Dry mass, DNA and non-histone protein determinations in lung cancer cells.

Cell nuclei from two biopsies of bronchial mucosa, seven squamous-cell carcinomas and six small-cell carcinomas of the lung were investigated. DNA and non-histone protein (NHP) content were simultaneously determined in Feulgen-Naphthol Yellow S-stained smears by means of multiple plug cytophotometry. In addition, the nuclear dry mass of cells originating from the same populations was measured by interference microscopy. DNA histograms of carcinomas were characterized by DNA stemlines being situated in the diploid range in four out of six small-cell carcinomas and in the hyperdiploid to hypertetraploid range in six out of seven squamous-cell carcinomas. Polyploid values (up to 8 c) were seldom found in small-cell carcinomas whereas squamous-cell carcinomas showed a broader dispersion approaching the 16 c level. The similarity of the NHP distributions with the DNA histograms was more marked in small-cell carcinomas than in the squamous-cell carcinomas. In comparison with the NHP distributions of normal bronchial epithelial cells, those of carcinomas were shifted to higher values. The increased NHP content was found to be a more prominent sign of malignancy in small-cell carcinomas than the DNA mass. The increase in nuclear dry mass in carcinomas was mainly caused by the accumulation of NHP in tumour cell nuclei.

Bronchi↗
PubMed1987

Histophotometrical measurements concerning the distribution of myofibrillar ATPase activity within the tissue block after aldehyde fixation.

The inhibition of myofibrillar ATPase activity by aldehyde fixation in tissue pieces of myocardium of the rat was measured by scanning histophotometry. The relative amount of the final reaction product of the histochemical method for ATPase (Padykula and Herman 1955) was taken as a measure for the enzyme activity. Along scanning lines in slides from the surface to the centre of tissue block, a higher activity was found in the centre in contrast to the marginal zone. Compared with the centre of the block (approximately equal to 100%), in the marginal region a loss of about 40% (in paraformaldehyde PFA) and of 75% (in glutaraldehyde GA) was found, the latter with a sharp decline between the marginal zone and the central part. For quantitative enzyme histochemistry by histophotometry unfixed material is recommended.

Adenosine Triphosphatases↗
PubMed1986

The correlation between histophotometrical and biochemical myosin-ATPase measurements in the myocardium and striated muscle of the rat.

To prove the correlation between histophotometrical and biochemical data of myosin-ATPase-activity, the change of enzyme activity during development was measured in the myocardium, masseter muscle, and tensor fasciae latae of rats. Both methods were applied to the same material. To avoid errors due to varying section thickness in each cutting and staining procedure, a reference material (e.g. heart muscle) was used, taken from one and the same animal. The correlation between histophotometrical and biochemical estimations was very good, histophotometrical arbitrary units being used. ATPase-activity in heart muscle during development, slightly decreases in masseter muscle and more in tensor fasciae latae. The ATPase-activity in the latter was higher than in masseter muscle. This is in good agreement with the physiological, biochemical, and histochemical classification.

Adenosine Triphosphatases↗
PubMed1986

Hydrolysis optimum of TCA Feulgen reaction on lymphocytes, liver cells, and Ehrlich ascites tumour cells.

For simultaneous cytophotometric measurements of DNA and protein the Feulgen hydrolysis must be performed with trichloracetic acid (TCA) at room temperature because of the preservation of nuclear proteins. Already after 10 h of hydrolysis, a good discrimination between the frequency peaks in the histogram is obtained. The best results are achieved after a hydrolysis time in the range of the maximum of the hydrolysis curve (20 h). At this time, little variations of hydrolysis duration scarcely influence the cytophotometric data.

Animals↗
PubMed1986

[Cytophotometric studies of urinary bladder tumors of various degrees of differentiation].

With the help of the scanning microscope photometry DNA content and size of Feulgen-stained cytoblasts may be measured. On smears of 28 tumours of the urinary bladder of all degrees of differentiation in each case 200 nuclei were investigated, the DNA and surface values were applied in histograms and these were compared one with another. With increasing dedifferentiation the mean nucleus-DNA content and the spreading of DNA and surface values significantly increased. The mean size of the nuclei did not increase. Increasingly ploidy deviations appeared--clinically significant for the recidivation. With the help of the proportion of non-diploid nuclei the histo-pathological graduation could be repeatedly performed and statements could be made as to the proliferative behaviour of tumours of the same classification. The "chromatin density" of non-diploid nuclei allowed the exact separation of the papillomas (Gx2) from the carcinoma preparations. The results are discussed on the basis of the literature.

Aged↗
PubMed1986

Cell cycle peculiarities of the Ehrlich ascites tumour as revealed by cell counting and flow cytometry.

Based on own investigations general principles of cell cycle analysis by quantitative microscopic methods are discussed. Cell cycle peculiarities of the Ehrlich ascites tumour (EAT) are demonstrated. The numerical data yield information on the underlying type of growth expressed by the logistic function (Verhulst-Pearl). The effective tumour development starts with an exponential phase. In EAT the 5th day is regarded as representative for this stage. Then after a transition phase a steady state is reached. The 11th day after transplantation reflects best this phase of tumour development. By flow cytometric measurements DNA frequency distributions can be obtained in dependence of tumour age. The interpretation of the practically useful height of the second frequency peak in the histograms is discussed in relation to the underlying type of growth. The evaluation of the measurements reveals a characteristic change of the relative duration of the cell cycle phases G1, S, G2 and of the percentage of cells within these phases. Multiparameter single cell measurements complete the cytometric cell cycle analysis in relation to the position of cells in the cell cycle and allow a distinction between quiescent and proliferating cells. Finally the application of the parameters assayed on the biological model is extended to tumours in man.

Animals↗
PubMed1985

A new system to consider varying section thickness in histophotometry.

The reference material, an exposed and developed x-ray film, was cutted together with the tissue specimen. By scanning microscope photometry, the mean optical density of the silver layer was measured. By this way, variations in section thickness are to be considered for histophotometrical investigations. A good proportionality between the optical density of the silver grain layer and the relative thickness of the clear film carrier, estimated by microinterferometry, was proved.

Histological Techniques↗
PubMed1985

Functionless retained pacing leads in the cardiovascular system. A complication of pacemaker treatment.

Twenty one patients with retained endocardial pacemaker leads were followed during a total observation period of 1097 months to assess the incidence of complications. Two patients developed thrombosis and occlusion of the superior vena cava, which was relieved by the development of a collateral venous circulation. In one patient the broken tip of the lead migrated to a pulmonary artery but did not cause overt complications. The remaining patients were free of symptoms. One patient died for reasons unconnected with pacemaker treatment. The good toleration of retained pacemaker leads by most patients indicates that major surgical procedures to remove the lead should be reserved for patients with life threatening complications, such as persistent infection or dangerous migration of the lead or both.

Aged↗
PubMed1985

[Practical application of logistic function to the growth of experimental tumors].

The properties of the logistic law of growth (Verhulst-Pearl) and a simple method for computing of statistical approximation are described. Two parameters are estimated: the generation rate c and the mortality rate c0, although the real biological processes are of greater complexity. The logistic law is modified by an additional term concerning the prefinal decline in the last life span. To prove the curve fitting to tumour growth by the modified logistic function the total number of Ehrlich ascites tumour cells was measured in 144 mice at 12 different times after inoculation. The accuracy of the curve fitting proved to be very good. Therefore the logistic function modified by an additional term for the final stages, is particularly suited for the characterization of Ehrlich ascites tumour growth and its changes.

Animals↗