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Biomedical subjects

J Rungby

Publications and source records attributed to J Rungby.

At least 37 records · Page 2Linked to original sources
PubMed1994

Systemic and local silver accumulation after total hip replacement using silver-impregnated bone cement.

In a patient, at revisional Christiansen total hip arthroplasty, silver-impregnated bone cement was used as prophylaxis against deep infection. Five years later the patient developed serious neurological deficits, and the prosthesis was loose. The loose Christiansen prosthesis and the silver-impregnated bone cement were removed and a Charnley prosthesis inserted. Intra-operatively the concentration of silver in fluid drawn from the hip joint was assessed to be about 1000 times the normal serum reference value, and tissue samples from the acetabulum were densely impregnated with silver. During the following 2 years the serum concentration of silver decreased from more than 60 times to 20 times the normal; simultaneously the patient partially recovered from her grave muscle paralysis.

Aged↗
PubMed1993

The von Kossa reaction for calcium deposits: silver lactate staining increases sensitivity and reduces background.

The classical von Kossa method has been modified: the high silver nitrate concentration in the original was replaced by 0.05% silver lactate with hydroquinone remaining the reducing agent of choice. The present modification stained calcification nodules with a sensitivity comparable to the original von Kossa reaction, but resulted in a reduced background staining in cultured osteoblasts. The method works well also with plastic- or paraffin-embedded tissue sections.

Calcification, Physiologic↗
PubMed1993

Comparison of the interaction of methyl mercury and mercuric chloride with murine macrophages.

The toxicity of organic methyl mercury was studied on murine macrophages in cell culture and compared to that of inorganic mercuric chloride. Long-term treatment of macrophage cultures with methyl mercury resulted in decreased cell viability in a concentration-dependent fashion. Experiments showed that 20 microM methyl mercury was highly toxic, causing cell death within a few days, while cultures exposed to lower levels were less severely affected. Comparison of the toxicity of organic and inorganic mercury by cell viability showed no difference between equimolar concentrations of methyl mercury and mercuric chloride. Furthermore, protein synthesis (interferon-alpha/beta) was reduced in a concentration dependent manner and had the same reduced magnitude in cells treated with either methyl mercury or mercuric chloride. However, impairment of random migration and phagocytosis of macrophages appeared at lower concentrations in cells exposed to methyl mercury than in cells exposed to mercuric chloride. Electron microscopy of cells exposed to methyl mercury revealed mercury deposits in lysosomes and dispersed in the cytoplasm and nuclei. The present study shows that methyl mercury and mercuric chloride impair cell viability and protein production in cell cultures at equimolar concentrations, while methyl mercury inhibits macrophage functions such as migration and phagocytosis at lower concentrations than mercuric chloride.

Animals↗
PubMed1993

Distribution of hydroxylated vitamin D metabolites [25OHD3 and 1,25(OH)2D3] in domestic pigs: evidence that 1,25(OH)2D3 is stored outside the blood circulation?

1. The distribution of 25-hydroxycholecalciferol (25OHD3) and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] in various organs from domestic pigs was examined by HPLC. 2. Plasma levels of both metabolites corresponded to those found in healthy human subjects. 3. Tissue concentrations of 25OHD3 in fat, kidney, liver, and intestinal mucosa were low (< 1/3 of plasma levels), whereas tissue concentrations of 1,25(OH)2D3 exceeded plasma levels by factors 3-7, adipose tissue concentrations being the highest. 4. Substantial amounts of activated vitamin D are stored outside the blood-streams and may actively participate in vitamin D and calcium homeostasis.

Animals↗
PubMed1993

Phagocytosis and stimulation of the respiratory burst in neutrophils by Pneumocystis carinii.

Phagocytosis and superoxide production of neutrophils stimulated with Pneumocystis carinii were studied using P. carinii obtained from rats and neutrophils and serum from healthy blood donors. Superoxide generation increased in a dose-related way to the number of pneumocysts added and was significantly higher when the parasites were opsonized. The use of heat-inactivated serum for opsonization reduced superoxide production somewhat, but not significantly. Preincubation of neutrophils with recombinant human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF) increased superoxide production in neutrophils stimulated with pneumocysts from 7.0 to 9.6 fmol/cell/20 min; however, the production in unstimulated cells increased by the same amount. Activation of the respiratory burst was paralleled by phagocytosis, and very few phagocytic vacuoles were found in neutrophils stimulated with unopsonized pneumocysts. By electron microscopy, various stages of cyst degradation were seen.

Animals↗
PubMed1993

Methyl mercury, mercuric chloride, and silver lactate decrease superoxide anion formation and chemotaxis in human polymorphonuclear leucocytes.

Cytotoxic effects of mercuric chloride, methyl mercury, and silver lactate on polymorphonuclear leucocytes have been examined by assaying superoxide anion formation capability and chemotaxis of metal-exposed cells. Both superoxide anion formation and chemotaxis were negatively affected by all three metal compounds. Both bacteriotoxic functions were affected in a dose-dependent fashion, the functional deficits were seen at doses not affecting cell viability. Dose-response curves were remarkably similar for all three compounds. The bacteriotoxic capacity of polymorphonuclear leucocytes may be hampered by mercury and silver.

Cell Survival↗
PubMed1992

Autometallographic silver-enhancement of colloidal gold particles used to label phagocytic cells.

The present paper demonstrates that colloidal gold silver-enhanced by autometallography (AMG) can be used to label phagocytic cells for light microscopic detection. Cultured macrophages were exposed to 0.5 microliters 6 nm colloidal gold particles for 24 or 48 h. Other cultures were exposed to 25 microliters of the same solution for 1 to 14 days. The staining was found to be stable also when new unmarked cells were applied. The colloidal gold had no adverse effect on the cells. The presented technique might also prove valuable for estimation of the total number of phagocytes in a culture or in an organism by applying labelled cells to culture or organism, and to ascertain the fate of a population of marked cells.

Animals↗
PubMed1992

Late postnatal growth in the dentate area of the rat hippocampus compensates for volumetric changes caused by early postnatal toluene exposure.

The present report assesses the reversibility of previously described quantitative morphological alterations in the dentate area of the hippocampi of rats exposed to 500 ppm toluene for 12 h daily from postnatal day 1 (P1) to P28. Following the exposure, rats were allowed to survive until P120. The volumes of hippocampal components, as they appear in Timm-stained histological sections, were determined using the Cavalieri estimator. At P120, no differences were apparent in the volumes of the dentate components of control and experimental animals. The differences observed immediately after exposure were eliminated by significantly larger increases in the sizes of early affected components in experimental animals. Different periods of neurogenesis in rodents and primates are briefly discussed as possible confounders of rodent models of permanent toluene-induced morphological alterations in primates.

Animals↗
PubMed1992

Experimentally induced lipid peroxidation after exposure to chromium, mercury or silver: interactions with carbon tetrachloride.

Chromium, along with other heavy metals, induces an increased production of malondialdehyde (MDA), an indicator of lipid peroxidation, in liver and kidney tissue of NMRI male mice. After acute intoxications MDA levels remain high for 60 min. and thereafter return to normal in the kidney whereas MDA levels in liver are still increased 48 hr after exposure. Exposure of mice to chromium, mercury, or silver and another stimulator of lipid peroxidation, carbon tetrachloride, showed synergism between inorganic mercury and CCl4. Pre-exposure to chromium, organic mercury, or silver at selected doses did not enhance CCl4-toxicity as measured by organ content of MDA.

Animals↗
PubMed1992

Ultrastructure of human osteoblasts and associated matrix in culture.

The ultrastructure, as visualized by transmission electron microscopy, of cells obtained from human bone explants and subsequently cultured is described along with the electron microscopic appearance of the associated intercellular matrix. The cells were characterized as osteoblasts on the basis of immunohistochemical, enzymatic, and functional criteria. Although the osteoblasts could be cultured in standard culture media and always appeared singly, not forming syncytia, the cultures were eventually confluent and formed multilayers. The cells were fusiform or cuboidal with diameters ranging between 10-15 microns. The cytoplasm was characterized by numerous large mitochondria, and especially by a very prominent RER. The intercellular matrix was woven with collagen fibres surrounding large numbers of matrix vesicles. In areas with matrix vesicles, evidence for osteoblast activity, i.e. mineralization related to matrix vesicles, could be observed after incubation with beta-glycerophosphate. In conclusion, we provide evidence that human osteoblasts cultured in vitro synthesize collagen and produce a matrix with vesicles capable of initiating mineralization processes.

Calcification, Physiologic↗
PubMed1992

Lipid peroxidation in early experimental diabetes in rats: effects of diabetes and insulin.

The degree of lipid peroxidation was measured in organs from diabetic rats receiving no treatment, and in those from insulin-treated diabetic rats and controls. Lipid peroxidation was measured as organ content of malondialdehyde, a degradation product of polyunsaturated fatty acids. In the kidney, lipid peroxidation was increased after one week of diabetes; insulin treatment reduced the level of lipid peroxidation to levels lower than seen in controls. In the liver, diabetes caused an increased lipid peroxidation, which could be reversed by insulin; no additional effect of insulin was found. In heart and pancreas no effects of diabetes or insulin were demonstrated. The present paper provides evidence that lipid peroxidation is increased in the early stages of experimental diabetes and is reversible by insulin treatment. Hyperinsulinaemia may, in itself, counteract lipid peroxidation in kidney.

Animals↗
PubMed1991

Ultrastructural localization of silver in rat testis and organ distribution of radioactive silver in the rat.

The deposition of silver after a single intravenous injection (2 micrograms Ag g-1 body weight) was studied in the testes of Wistar rats 24 h and 1 and 2 weeks after dosing with radiolabelled 110AgNo3 (2 micrograms Ag and 1.2 kBq g-1 body weight). Also, the temporal accumulation of silver during the experimental period was monitored in the blood, testes, epididymides, kidney, liver and brain. The subcellular distribution of silver within the testes was demonstrated by using the histochemical technique of autometallography. Silver was cleared rapidly from the blood. After an initial rise, concentrations in organs remained almost stable throughout the experimental period. Silver was especially abundant in interstitial macrophages and in the basement membrane. Deposits of silver were found in all cell types of spermatogenesis and in the lysosomes of the Sertoli cells.

Animals↗
PubMed1991

Formation of osteoclasts and osteoblast-like cells in long-term human bone marrow cultures.

A culture system for human osteoclasts is described. It is based on incubation of mononuclear marrow cells for three weeks in the presence of 1,25 dihydroxyvitamin D3. The resulting cells exhibited all the classic characteristics of osteoclasts. They formed a true syncytium with up to 25 nuclei per cell. The cells revealed a strong positive reaction for tartrate-resistant acid phosphatase and a ruffled border. When these cells were cultured on 100 microns thick human dentine slices for three weeks, typical resorption pits were formed. In the culture, alkaline phosphatase-positive osteoblast-like cells were formed in the vicinity of osteoclasts. This culture system permits studies of human osteoclasts and their interaction with osteoblast cell precursors in the human bone marrow.

Acid Phosphatase↗
PubMed1991

Tuberous sclerosis and parathyroid adenoma.

Very little is known about the pathogenesis of tuberous sclerosis. Over the past 10 years, however, increasing numbers of reports on adenomatous diseases in association with tuberous sclerosis have been published. A case of hypercalcaemia and parathyroid adenoma in association with tuberous sclerosis is presented, of which there has been one such report published previously. This association might be another manifestation of this complex disease: it is therefore recommended that plasma calcium concentrations should be measured in such patients.

Adenoma↗
PubMed1990

The effect of low-level toluene exposure on the developing hippocampal region of the rat: histological evidence and volumetric findings.

With the intention of investigating possible morphological alterations effected by toluene in the developing CNS, rat pups were exposed to 100 ppm and 500 ppm of atmospheric toluene from postnatal day 1 until sacrifice at postnatal day 28, when the hippocampal region (area dentata, Ammon's horn, subiculum) was examined light microscopically and alterations in the volumes of the layers of the subdivisions were determined. The layers of Ammon's horn and the subiculum were not affected qualitatively or quantitatively by the 500 ppm exposure. Within the area dentata, the volume of the granule cell layer was 6% smaller in animals exposed to 100 ppm and 13% smaller in animals exposed to 500 ppm than they were in controls. The volumes of the hilus, which is a terminal field of granule cell axons, and the commissural-associational zone of the dentate molecular layer, which is the terminal field of the hilar projection to the granule cells, were smaller (12% and 19%) in animals exposed to 500 ppm than they were in controls. Argyrophilic cells were found in the granule cell layer of all animals exposed to 500 ppm. Pronounced granule cell degeneration was found in one animal exposed to 500 ppm. The granule cell layer of animals exposed to 100 ppm appeared qualitatively normal. The alterations reported here support the few earlier reports of morphological alterations in the CNS of adult laboratory animals. Effects of toluene similar to those described, that is alterations in specific neuron populations and their afferent and efferent terminal fields may complement changes in neurophysiology and behavior that have been observed in prenatally and perinatally exposed rodent pups. Causal relationships, however, remain to be elucidated.

Animals↗
PubMed1990

Traces of mercury in organs from primates with amalgam fillings.

In order to trace possible accumulations of mercury, three vervet monkeys received occlusal amalgam fillings, three others maxillary bone implants of amalgam, and three untreated monkeys served as controls. One year later all animals were sacrificed by transcardial perfusion with glutaraldehyde. Tissue sections from different organs were subjected to silver amplification by autometallography and analyzed at light and electron microscopical levels. It was found that amalgam fillings (total, 0.7-1.2 g) caused deposition of mercury in the following tissues: spinal ganglia, anterior pituitary, adrenal, medulla, liver, kidneys, lungs, and intestinal lymph glands. In monkeys with maxillary silver amalgam implants (total, 0.1-0.3 g), mercury was found in the same organs except for liver, lungs, and intestinal lymph glands. Organs from the three control animals were devoid of precipitate. To evaluate whether silver released from the corroding amalgam fillings added to the staining pattern, tissue sections were exposed to potassium cyanide prior to being autometallographically developed. This treatment removes all traces of silver, leaving mercury sulfide accumulation untouched. By comparing sections that had been exposed to cyanide with untreated parallels no difference was seen in the pattern confirming that mercury was the only catalyst present in the tissue. These results strongly support what has been suggested previously that dental fillings in primates cause absorption of mercury released from amalgam fillings through lungs and intestinal tract, and that depending on exposure mercury is distributed to most organs and will eventually be found in the central nervous system. The present data also show that silver released from the corroding filling is not absorbed.

Animals↗