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Biomedical subjects

K Király

Publications and source records attributed to K Király.

At least 19 recordsLinked to original sources
PubMed2001

Age matters: collagen birefringence of superficial articular cartilage is increased in young guinea-pigs but decreased in older animals after identical physiological type of joint loading.

OBJECTIVE: To compare responses of the collagen network and glycosaminoglycans (GAGs) of articular cartilage to physiological type of joint loading in young growing and adult mature guinea-pigs. DESIGN: 10- and 44-week-old guinea-pigs were accustomed to treadmill running for 3 weeks. Thereafter the animals ran 2500 m/day, 5 days a week, for 15 weeks. Articular cartilage specimens from knee joints were collected at 28 and 62 weeks. Osteoarthritis (OA) prevalence and severity was evaluated by aid of light microscopy. The degree of collagen fibril network organization and content was analyzed with quantitative polarized light microscopy. The local concentration of GAGs was determined from cartilage sections with digital densitometry after safranin-O staining. RESULTS: In the young guinea-pigs, running increased up to 24% the optical retardation of polarized light by collagen in the superficial articular cartilage of femur, indicating either a higher degree of fibril assembly and organization or increased amount of collagen, or both. In contrast, in the adult mature animals the optical retardation decreased almost 50% after joint loading (P< 0.01-0.001). Running did not increase cartilage fibrillation. Significant changes in GAG content of cartilage were not found either in the young or adult mature runners. CONCLUSIONS: Increased birefringence of the superficial articular cartilage after joint loading in young guinea-pigs can be interpreted to be a sign of improved and decreased birefringence in older animals a sign of worsened property of the collagen network. It can be suggested therefore that joint loading strengthened the collagen network in the young runners. It can be hypothesized further that with time the inferior property of the collagen network predisposes the older runners to earlier OA than in controls.

Aging↗
PubMed2001

Effects of intra-articular injections of bufexamac suspension in healthy horses.

OBJECTIVE: To evaluate the effects of intra-articular (IA) injections of bufexamac in horses, focusing particularly on the effects of bufexamac on articular cartilage. ANIMALS: 20 Standardbreds. PROCEDURE: Horses were randomly allocated into 4 groups consisting of 5 horses each, and 20, 60, or 100 mg of bufexamac or 1 ml of sterile saline (0.9% NaCl) solution (control) was injected into 1 intercarpal joint at weekly intervals for 6 treatments (days 0, 7, 14, 21, 28, and 35). Clinical signs and results of hematologic, serum biochemical, and synovial fluid (SF) analyses and radiography were used to evaluate treatment effects. On day 49, all horses were euthanatized; gross necropsy and histologic examinations of internal organs and articular tissues were performed. Glycosaminoglycan concentration of the articular cartilage was evaluated in safranin O-stained sections by use of a semiquantitative microspectrophotometric method. RESULTS: No systemic signs were observed. Temporary mild to moderate heat and effusion were the only clinical signs observed in a number of joints after IA injections and more often only in the 100 mg group, compared with controls. The 100 mg dose resulted in significant increases in SF WBC counts, with relative neutrophilia and SF total protein concentration 24 hours after injection (day 1). No lesions suggestive of toxic effects were detected at necropsy or on histologic examination. No changes in articular cartilage glycosaminoglycan concentration were detected. CONCLUSIONS AND CLINICAL RELEVANCE: Six injections of 20, 60, or 100 mg of bufexamac at weekly intervals did not cause any untoward systemic or local effects. These data suggest that bufexamac is a safe nonsteroidal anti-inflammatory drug for IA administration in horses.

Animals↗
PubMed1998

Articular cartilage collagen birefringence is altered concurrent with changes in proteoglycan synthesis during dynamic in vitro loading.

INTRODUCTION: The articular cartilage collagen network and proteoglycans are subject to changes in deteriorating joint diseases. In this study, we exposed articular cartilage plugs to cyclic loading and investigated the properties of collagen network and proteoglycans in different zones of the articular cartilage. METHODS: Articular cartilage full-depth plugs were exposed in vitro to 4.1 MPa cyclic (0.5 Hz) loading for 1 to 20 hr and investigated using quantitative microscopic methods (i.e., polarized light microscopy, microspectrophotometry, and autoradiography). RESULTS: The loading caused packing or condensation of the tissue. In histological sections, the height of uncalcified articular cartilage decreased by an average of 12.8% (range, 4 to 19.7%). Loading increased the birefringence of collagen in the superficial cartilage (P < 0.05), with thickening of the zone up to 41.4% at 20 hr. The thickness of the intermediate zone increased also (22% at 1 hr and 434% at 20 hr). Concomitantly, the birefringence (P < 0.05) and the thickness of the deep zone decreased (18.5 to 27.8%). Loading for 4 hr increased the 35S-sulphate incorporation of the cartilage explants by an average of 67% (P < 0.05). The increase was most significant in the deep cartilage. A simultaneous increase was observed in the proteoglycan concentration of the cartilage; the staining intensity with safranin-O increased by 8.8% (P < 0.05). After 8 hr loading, this stimulation decreased; at 20 hr, loading caused a clear inhibitory effect on proteoglycan synthesis in the superficial zone. DISCUSSION: According to these results, the chosen loading regimen increased the thickness and collagen orientation in the superficial zone. In contrast, the thickness and birefringence in the deep cartilage were reduced. The proteoglycan metabolism of chondrocytes was first stimulated deep in the cartilage, but as the loading continued, the effect proved to be inhibitory (especially in the superficial part of uncalcified cartilage).

Animals↗
PubMed1997

Specimen preparation and quantification of collagen birefringence in unstained sections of articular cartilage using image analysis and polarizing light microscopy.

To establish an optimal method for analysis of the collagen structures from unstained tissue sections, a computerized image analysis system using a charge coupled device camera coupled to a polarizing light microscope was used. Retardation values of birefringence, which are proportional to the content and fibril orientation of collagen in the extracellular matrix of articular cartilage, were determined from sections prepared in different ways. In the superficial zone of articular cartilage, the highest retardation values were recorded from sections cut parallel to the so-called split lines indicating the anisotropic arrangement of collagen. Complete digestion of glycosaminoglycans reduced the retardation value by approximately 6.0%, suggesting a minor, but not insignificant, contribution of glycosaminoglycans to the birefringence of the matrix. The use of a mounting medium with a refractive index close to that of the collagen (e.g. DPX) increased the specificity of the method, since the optical anisotropy of collagen derives predominantly from the intrinsic (structural) birefringence. In conclusion, analysis of unstained sections after careful removal of paraffin and glycosaminoglycans from the tissues provides a sensitive and rapid quantitative assessment of oriented collagen structures in articular cartilage.

Animals↗
PubMed1997

Training a large number of laboratory mice using running wheels and analyzing running behavior by use of a computer-assisted system.

A great many studies in the literature describe the variety of ways to provide physical training to small laboratory animals. Forced running on a treadmill or swimming training require considerable effort from the researcher, but permit the investigator to control the amount of exercise. Another option is to provide animals with access to running wheels, which they can voluntarily operate. Wheels can be used to investigate the running behavior of the animals. Wheel motion usually has been detected with magnets and microswitches and has been recorded using strip chart recorders or electromechanical counters. Computers also have been used in recording, but the measured parameters usually have been able to define only the total distance run in a fixed period. We designed a system, using running wheels, that can be used for long periods, up to years, for training a large number of laboratory mice simultaneously (maximal n = 96). The running parameters estimated by our system include running distance, speed, and time. Cumulative estimates of the running parameters can be produced for any period, as short as 1 sec. It is also easy to perform statistical analyses on the data. Using the system, we investigated the running behavior of 21 young C57BL/6 male mice. After the fast growth period, until 8 weeks of age, the mice ran 4 to 5 km/day at an average speed of 23 m/min, and spent 3 h running each day. This took place during the hours of darkness.

Animals↗
PubMed1996

Application of selected cationic dyes for the semiquantitative estimation of glycosaminoglycans in histological sections of articular cartilage by microspectrophotometry.

Selected commonly used cationic dyes, viz. Thionin, Safranin O, Toluidine Blue O, Dimethylmethylene Blue, Cuprolinic Blue, Cupromeronic Blue, N,N'-Diethylpseudoisocyanine, and a modified PAS-method, and staining methods with a variety of alternative procedures, e.g., variation of pH, use of the critical electrolyte concentration method, and blocking reactions (methylation-saponification, carboxymethylation), were tested to select optimal staining procedures for the semiquantitative histochemical estimation of glycosaminoglycans by microspectrophotometry in sections of articular cartilage. The methods were carried out on 3 microns-thick paraffin and 1 microns-thick glycolmethacrylate sections of bovine articular cartilage. The staining intensity of the sections was measured from spots 25 microns apart using a Leitz MPV 3 microspectrophotometer, starting at the surface of the cartilage and ending up at the tidemark. The result was compared with the fixed-charge density graph determined from the adjacent articular cartilage. Of the dyes tested, Thionin and Safranin O proved to be excellent cationic dyes for the histochemical quantification of cartilage matrix proteoglycans, since the staining intensity curves showed a linear correlation (r = 0.900-0.995) with the fixed charge density curves from the adjacent cartilage. Also, the stain distribution was consistently uniform across the sections. In 1 microns-thick glycolmethacrylate sections, the Safranin O staining gradient showed almost perfect identity with the fixed-charge density curve. Cuprolinic Blue and Cupromeronic Blue combined with the critical electrolyte concentration technique were also useful for the microspectrophotometric assays of glycosaminoglycans, but the presence of metachromasia should be checked prior to the measurements. The reliability of blocking procedures for quantitative histochemical work was not convincing.

Animals↗
PubMed1996

Safranin O reduces loss of glycosaminoglycans from bovine articular cartilage during histological specimen preparation.

The ability of Safranin O, added to fixation and decalcification solutions, to prevent the escape of glycosaminoglycans (GAGs) from small cartilage tissue blocks during histological processing of cartilage has been studied. GAGs in the fixatives and decalcifying solutions used and those remaining in the 1 mm3 cubes of cartilage were assayed biochemically. The quantity of GAGs remaining in the cartilage cubes were determined from Safranin O-stained sections using videomicroscopy or microspectrophotometry. A quantity (10.6%) of GAGs were lost during a conventional 4% buffered formaldehyde fixation (48 h) and a subsequent decalcification in 10% EDTA (12 days) at 4 degrees C. Roughly one-quarter of the total GAG loss occurred during the 48 h fixation, and three-quarters during the 12 days of decalcification. Inclusion of 4% formaldehyde in the decalcification fluid decreased the loss of GAGs to 6.2%. The presence of 0.5% Safranin O in the fixative reduced this loss to 3.4%. When 0.5% Safranin O was included in the fixative and 4% formaldehyde in the decalcification solution, Safranin O staining of the histological sections increased on average by 13.5%. After fixation in the presence of 0.5% Safranin O, there was no difference in the staining intensities when decalcification was carried out in the presence of either Safranin O or formaldehyde, or both. It took 24 h for Safranin O to penetrate into the deep zone of articular cartilage, warranting a fixation period of at least this long. In conclusion, the addition of Safranin O to the fixative and either Safranin O or formaldehyde in the following decalcification fluid, markedly reduces the loss of GAGs from small articular cartilage explants during histological processing. However, for immunohistochemical studies, Safranin O cannot be included in the processing solutions, because it may interfere.

Animals↗
PubMed1981

R-plasmid study of an outbreak caused by multiresistant strains of Salmonella panama.

A salmonella panama outbreak was observed in the months May through July, 1979, in the newborn and intensive wards of a paediatric hospital. The isolates proved to be multiresistant to antibiotics. To clarify the presumed R-plasmid nature of the multiresistance, the transfer of the resistance to five antibiotics, viz. ampicillin, chloramphenicol, streptomycin, kanamycin and tetracycline, was studied. Escherichia cole K12 Nalr, the strain used as recipient, acquired resistance simultaneously to four antibiotics, viz. ampicillin, chloramphenicol, streptomycin and kanamycin. The minimum inhibitory concentration for the transconjugants agreed well with that of the original S. panama strain. Resistant and multiresistant E. coli. strains not belonging to serogroups associated with infantile enteritis were isolated from the intestinal flora of several patients and symptomless carriers. Elimination of the transmissible multiresistance was observed in 0.15-1.1% of the strains.

Anti-Bacterial Agents↗
PubMed1979

A new method for obtaining viable cells from dermal infiltrates. A study on 2,4 dinitrochlorobenzene induced contact dermatitis.

Experimental contact dermatitis has been induced in 2,4 dinitrochlorobenzene (DNCB) sensitized guinea pigs. The developing dermal infiltrate was excised and the infiltrating cells were obtained by mechanical extraction alone as well as by the combination with collagenase and elastase treatment. The most viable cells appeared in the elastase and mechanically extracted samples and the least in those subjected to mechanical treatment alone. The most cells in the enzyme-treated samples were present 24 h after re-exposure of the sensitized animals to DNCB consisting mainly of lymphocytes and of polymorphonuclear granulocytes. The optimum conditions for the action of enzymes including optimum duration of the treatment, buffer milieu, aspecific proteolytic effect on foreign substrate and action on T and B cell receptors have been elaborated. It was concluded that 80 min of collagenase treatment with gentle mechanical extraction under specified conditions does not affect any measurable immunologic properties of the liberated cells resulting in the second best yield. A comparison of these data with earlier reports and their significance is being discussed.

Animals↗
PubMed1979

Isomorphic skin reaction with DNCB in SLE and DLE.

DNCB sensitization was studied in 76 cases of systemic and 44 of discoid lupus erythematosus and in 101 immunosuppressed and tumor patients as controls, as well as in 40 contact-sensitized eczematous and 115 unselected patients. Sensitization of patients with discoid LE and that of mixed patients are of the same order, while it is lower in the systemic LE group. The highest incidence was found in the polysensitized positive control group; the lowest in the immunosuppressed and tumor patients. DNCB sensitization showed clear age dependency in the different groups. At the site of the DNCB exposure, isomorphic reactions were found in 43% of discoid and 25% of systemic LE patients. Histological and immunofluorescence studies supported the findings of the clinical picture, i. e. the appearance of isomorphic reactions at the site of the exposure cannot be related either to the intensity of the early reaction or with the developing intensity.

Adult↗
PubMed1979

Effect of KCN on the motility of Treponema pallidium.

Virulent Treponema pallidum has been shown to survive in KCN-containing artificial medium. Oxygen uptake being sensitive to cyanide, the observation indicates that treponemes do not have a cytochrome oxidase system. KCN had a killing effect only at a 15--30 mM final concentration. The data show that the Budapest strain of T. pallidum is an anaerobic organism.

Animals↗