Biomedical subjects

M Stoltenberg

Publications and source records attributed to M Stoltenberg.

At least 19 recordsLinked to original sources

PubMed2006

Zinc ions in the endocrine and exocrine pancreas of zinc deficient rats.

OBJECTIVE: Zinc deficiency is a problem world-wide. Zinc and insulin are intimately related, and a reduced zinc intake may affect glucose metabolism. The present study investigates how subclinical zinc deficiency in rats affects glucose metabolism and zinc distribution in the pancreas. METHODS: Glucose metabolism was evaluated by blood-glucose, serum insulin, homeostasis model assessment (HOMA), and intraperitoneal glucose tolerance tests. Immersion zinc-sulphide autometallography (iZnSAMG) was used to describe zinc ion distribution. RESULTS: After 4 weeks on a zinc deficient diet (<10 ppm), the zinc deficient rats had a slightly impaired glucose metabolism characterized by significantly increased blood-glucose levels. No differences in serum insulin, insulin resistance, beta-cell function were observed. The zinc deficient rats had significantly decreased serum zinc without any clinical signs of zinc deficiency. Zinc ion staining intensity of the islets of Langerhans was unaffected by the zinc deficiency. In contrast, the acinar cells in the exocrine pancreas appeared depleted of iZnSAMG grains in the zinc deficient rats when compared with their controls. Though statistically non-significant, a reduction in total zinc of the pancreas was found. CONCLUSIONS: The present findings suggest that the endocrine pancreas is able to compensate for the subclinical zinc deficiency as it maintains an adequate zinc ion level in the secretory vesicles for insulin storage. The exocrine pancreas lacks this ability; it exhibits decreased levels of zinc ion staining as a consequence of 4 weeks of reduced zinc intake.

Animal Feed↗

PubMed2005

Immersion autometallographic tracing of zinc ions in Alzheimer beta-amyloid plaques.

An easy to perform autometallographic technique (AMG) for capturing zinc ions in Alzheimer plaques is presented. The possibility of visualizing loosely bound or free zinc ions in tissue by immersion autometallography (iZnS(AMG)) is a relatively recent development. The iZnS(AMG) staining is caused by zinc-sulphur nanocrystals created in 1-2 mm thick brain slices that are immersed in a 0.1% sodium sulphide, 3% glutaraldehyde phosphate buffered solution, the NeoTimm Solution (NTS), for 3 days. When the zinc-sulphur nanocrystals are subsequently silver-enhanced by autometallography, the plaques are readily identified as spheres of dark interlacing strands of different sizes, embedded in the pattern of zinc-enriched terminals. The zinc specificity of the iZnS(AMG) technique was tested by immersion of brain slides in the chelator DEDTC prior to the NTS immersion. The iZnS(AMG) detection of zinc ions is easily standardized and can be used in the quantification of plaques with stereological methods. This technique is the first to detect zinc in plaques in the cerebellum of transgenic PS1/APP mice and the first to detect zinc ions in plaques and dystrophic neurites at electron microscopical levels.

Aged↗

PubMed2005

Zinc fluxes during acute and chronic exposure of INS-1E cells to increasing glucose levels.

Zinc in beta-cell secretory vesicles is essential for insulin hexamerization, and tight vesicular zinc regulation is mandatory. Little is known about zinc ion fluxes across the secretory vesicle membrane and the influence of changes in the extracellular environment on vesicular zinc. Our study aim was to investigate the effect of acute and chronic exposure to various glucose concentrations on zinc in secretory vesicles, the relation between zinc and insulin, and the presence of two zinc transporters, ZnT1 and ZnT4, in INS-1E cells. Zinc ions were demonstrated and semi-quantified using zinc-sulfide autometallography. Insulin content and secreted insulin were measured. Measurements were made on INS-1E cells after exposure to 2.0, 6.6, 16.7, and 24.6 mmol/l glucose for 1, 24, and 96 hours. 1h: Increasing glucose resulted in no changes in intravesicular zinc ions at 2, and 24.6 mmol/l glucose, but a slight increase at 16.7 mmol/l glucose. 24 and 96 h: Increasing glucose led to decreased vesicular zinc ion content accompanied by a decrease in insulin content. ZnT1 and ZnT4 were present in the cytoplasm. Our results demonstrate that intra-vesicular zinc ions respond to changes in the extra-cellolar glucose concentration, especially during chronic high glucose concentrations, where the content of vesicular zinc ions decreases.

Animals↗

PubMed2005

Effects of short-term hypoxia on neuroglobin levels and localization in mouse brain tissues.

Nerve cells are highly susceptible to ischemic and hypoxic injuries. The neuroglobin (Ngb), found in vertebrate nerve cells, has been suggested to protect nerve cells from ischemic episodes by a yet unknown mechanism. However, contradicting reports exist regarding localization and up-regulation of Ngb in response to hypoxia. The aim of the present study was to probe the distribution of Ngb proteins in mouse brain and retina by immunohistochemistry, and to quantify the levels of Ngb mRNA by reverse-transcription-polymerase chain reaction (RT-PCR) after short-term (2 h) exposure to 7.6% oxygen. We found Ngb to be present throughout the neocortex, most abundantly in the perirhinal, entorhinal and temporal cortical areas, the thalamus and hypothalamus, the choroid plexus, the olfactory bulb and the cranial nerve nuclei in the brainstem. Intense staining was observed in the mesencephalic central grey area and the Purkinje cells. Two-hour hypoxic exposure caused no detectable changes in staining intensity or spatial distribution of Ngb neither in the Purkinje cells nor in any other brain areas observed. The RT-PCR data supported the lack of differences in brain Ngb levels between normal and oxygen-deprived animals. In the retina, Ngb localization by immunohistochemistry was confined to the inner segments of the photoreceptors, the plexiform layers and the ganglion cells. Short-termed hypoxia did not change retinal Ngb levels as assessed by both techniques. The lack of Ngb up-regulation in the brain is consistent with results from previous long-term hypoxic experiments, suggesting that Ngb is not regulated by pure hypoxia in vivo.

Animals↗

PubMed2003

Zinc ions in beta-cells of obese, insulin-resistant, and type 2 diabetic rats traced by autometallography.

Zinc ions in the secretory granules of beta-cells are known to glue insulin molecules, creating osmotically stable hexamers. When the secretory granules open to the surface, the zinc ion pressure decreases rapidly and pH levels change from acid to physiological, which results in free insulin monomers and zinc ions. The released zinc ions have been suggested to be involved in a paracrine regulation of alpha- and beta-cells. Since zinc is intimately involved in insulin metabolism and because zinc homeostasis is known to be disturbed in type 2 diabetes, we decided to study the ultrastructural localisation of zinc ions in insulin-resistant and type 2 diabetic rats as compared to controls. By means of autometallography, the only method available for demonstrating zinc ions at ultrastructural levels, we found zinc ions in the secretory granules and adjacent to the plasma membrane. The membrane-related staining outside the plasma membrane reflects release of zinc ions during exocytosis. No apparent difference was found in the ultrastructural localisation of zinc ions when we compared the obese Zucker (fa/fa) rats, representing the insulin resistance syndrome, and the GK rats, representing type 2 diabetes, with controls. This suggests that the ultrastructural localisation of zinc ions is unaffected by the development of type 2 diabetes in rats in a steady state of glycaemia.

Animals↗

PubMed2003

An autometallographic technique for myelin staining in formaldehyde-fixed tissue.

A new autometallographic (AMG) technique for staining myelin in formaldehyde- or paraformaldehyde- (PFA) fixed tissue is presented. The tissue sections were exposed to AMG development without prior treatment with silver salts. The method was examined on PFA-fixed tissue from mouse, rat, pig, and formaldehyde-fixed human autopsy material. Samples from brain, spinal cord, cranial, and spinal nerves were either cut on a vibratome, frozen and cryostat sectioned, or embedded and microtome sectioned, before AMG development and counterstaining. The AMG-myelin technique results in a specific black/dark-brown staining of myelin in all parts of the CNS and PNS. It works on all species examined, independent of the histological preparation techniques applied. The AMG staining is stable, stays unchanged through decades, allows counterstaining, and has previously been used with immunohistochemical techniques. On perfusion-fixed tissue the technique works without further fixation, but the intensity of the AMG-myelin staining is increased by increased postfixation time. Additionally, immersion fixation has to last for days depending on the size of the tissue block in order to obtain proper myelin staining. The most feasible explanation of the chemical events underlying the AMG-myelin technique is that nano-sized clusters of metallic silver are formed in the myelin as a result of chemical bounds with reducing capacity, exposed or created by the formaldehyde molecule. The AMG method is simple to perform and as specific as the conventional osmium and luxol fast blue stainings. The present technique is thus an effective, simple, inexpensive, and quick myelin staining method of formaldehyde- or PFA-fixed tissue.

Animals↗

PubMed2003

In vivo cellular uptake of bismuth ions from shotgun pellets.

Shotgun pellets containing bismuth (Bi) are widely used and may cause a rather intense exposure of some wild animals to Bi. A Bi shotgun pellet was implanted intramuscularly in the triceps surae muscle of 18 adult male Wistar rats. Another group of 9 animals had a Bi shotgun pellet implanted intracranially in the neocortex. Eight weeks to 12 months later the release of Bi ions was analysed by autometallography (AMG) of tissue sections from different organs (brain, spinal cord, kidney, liver, testes). In the group with intramuscular Bi shotgun pellets no AMG staining could be found for the first 2-4 months; 6 months after exposure Bi was traced in the kidney. Twelve months after the implantation the kidneys were heavily loaded and Bi was also traced in testosterone-producing Leydig cells, in glial cells and in neurons of brain and spinal cord. In the central nervous system (CNS) motor neurons were the most loaded. In rats with intracranially implanted shotgun pellets a massive uptake of Bi was observed involving both glia and neurons throughout the brain. The cells close to the shotgun pellet had the highest uptake. The animals showed a pronounced Bi uptake in the ependyma cells lining the ventricular system and in the cubic epithelia covering the choroid plexus. Dissemination of Bi ions to the rest of the body was demonstrated by AMG tracing of Bi accumulations in the tubular cells of the kidney. These findings emphasize that metallic Bi, including shotgun pellets, represents sites of intense Bi pollution if implanted or shot into a living organism, and further that such metallic Bi bodies, if they enter the CNS, cause a spread of Bi ions throughout it.

Animals↗

PubMed2002

Bismuth-induced lysosomal rupture in J774 cells.

Bismuth-containing drugs have several applications, one being their use against Helicobacter pylori-associated peptic ulcers, and bismuth has been discovered in macrophages at the base and margins of peptic ulcers. In the present study, the autometallographic technique for the histochemical demonstration of bismuth was applied, showing that bismuth citrate-exposed J774 cells accumulate the metal in their lysosomes. Such accumulations resulted in lysosomal rupture - assayed by the acridine orange uptake technique and flow cytofluorometry - and ensuing apoptotic cell death.

Acridine Orange↗

PubMed2001

[Mortality of invasive malignant cutaneous melanoma. A review with special consideration of gender distribution].

BACKGROUND AND OBJECTIVE: The final goals of malignant melanoma prevention are lowering incidence and mortality. We assessed the parameter "survival" for both men and women as the beginning point for future gender-directed prevention campaigns. We compared the periods 1972-1980, 1981-1988, 1989-1996, and determined the influence of age and of Breslow' tumor thickness on survival. PATIENTS/METHODS: We had sufficient follow-up on 10.433 patients. We calculated survival curves according to Kaplan-Meier and defined differences by the logrank test. RESULTS: At all periods of time, survival of women was higher compared with men, but with no impressive changes over time. This was especially true for younger men. The most important prognostic factor was the Breslow tumor thickness. Within all periods of time, its median was higher in men. A trend downwards for both genders could be observed with higher influence on survival in men. CONCLUSIONS: Our findings justify melanoma prevention campaigns addressed to men. Evaluation of such campaigns has to take into account an already existing upwards trend for male survival, which exceeds that of female survival.

Adolescent↗

PubMed2001

Retrograde axonal transport of bismuth: an autometallographic study.

Bismuth subnitrate was injected into the triceps surae muscle of 3-month-old male Wistar rats. Sections of lumbar spinal cord (L4-L6) and corresponding dorsal root ganglia were developed by autometallography (AMG) to trace possible bismuth in neuronal somata resulting from retrograde axonal transport. At 3 days after treatment bismuth clusters could be traced by AMG in spinal cord motor neurons and in dorsal root ganglion cells ipsilateral to the injection site. Retrograde transport of bismuth could be avoided by ligation or intraneuronal injection of cholchicine into the sciatic nerve. At the ultrastructural level bismuth was found to be located exclusively in lysosome-like organelles in motor and sensory neuronal somata projecting to the injection site. The present study shows that bismuth is transported retrogradely in both sensory and motor axons if their terminals are exposed to bismuth ions.

Animals↗

PubMed2001

Autometallography allows ultrastructural monitoring of zinc in the endocrine pancreas.

Zinc is intimately involved in insulin metabolism, its major known role being the binding of insulin in osmotically stable hexamers in beta-cell granules. To investigate the anatomical distribution of zinc ions necessary for insulin binding we examined the rat pancreas by autometallography (AMG). AMG demonstrates chelatable zinc and is a sensitive marker for zinc in vesicles and also a surrogate marker for recently described zinc pumps regulating intravesicular zinc metabolism. Zinc ions were found in alpha- and beta-cell granules, primarily in the periphery of the granules. Only occasionally was zinc seen in other islet cell types. AMG allows the study of the microscopic and ultrastructural localisation of free zinc ions in the pancreas. The applicability of the method at the ultrastructural level in particular makes AMG a very sensitive tool in future studies on the role of zinc ions in the pancreas.

Animals↗

PubMed2001

Studies on YKL-40 in knee joints of patients with rheumatoid arthritis and osteoarthritis. Involvement of YKL-40 in the joint pathology.

OBJECTIVE: The presence of YKL-40 (human cartilage glycoprotein 39) in synovium, cartilage and synovial fluid (SF) from knee joints of patients with rheumatoid arthritis and osteoarthritis (OA) were related to histopathological changes in synovium and cartilage and to serum YKL-40 and other biochemical markers. METHODS: The localization of YKL-40 in synovium and cartilage was determined by immunohistochemistry. Synovial inflammation was estimated histologically and by magnetic resonance imaging (MRI). Biochemical markers of inflammation, neutrophil activation and cartilage metabolism were analysed. YKL-40 concentrations in serum and SF were determined by RIA and ELISA. RESULTS: In the synovium YKL-40 positive cells were found in lining and stromal cells (macrophages) and the number of YKL-40 positive cells was related to the degree of synovitis. In arthritic cartilage, YKL-40 was located to chondrocytes. YKL-40 levels in SF were higher in RA patients with moderate/severe or none/slight synovitis of the knee joint compared to OA patients with moderate/severe or none/slight synovitis. SF YKL-40 correlated with the synovial membrane and the joint effusion volumes determined by magnetic resonance imaging (MRI) and with other biochemical markers of intercellular matrix metabolism. SF YKL-40 was higher than serum YKL-40, and a relationship existed between the YKL-40 levels in SF and serum. Intraarticular glucocorticoid injection was followed by clinical remission and a decrease in serum YKL-40, which increased again at clinical relapse. CONCLUSIONS: YKL-40 in SF is derived from cells in the inflamed synovium, chondrocytes and SF neutrophils. Joint derived YKL-40 influences serum YKL-40. YKL-40 may be involved in the pathophysiology of the arthritic processes and reflect local disease activity.

Adipokines↗

PubMed2001

Serum levels of parathyroid hormone and markers of bone metabolism in patients with rheumatoid arthritis. Relationship to disease activity and glucocorticoid treatment.

OBJECTIVE: To evaluate the influence of inflammatory activity and glucocorticoid (GC) treatment on serum parathyroid hormone (s-PTH) and bone metabolism in patients with rheumatoid arthritis (RA). Furthermore, in patients with active RA, to examine the PTH secretion and Ca2+ set point before and after treatment with GC. METHODS: A range of biochemical markers of bone metabolism and calcium homeostasis were measured in 95 patients with definite RA stratified into groups according to disease activity and GC treatment. In a subgroup of 12 patients with active disease, initiating slow-acting-anti-rheumatic-drugs (SAARDs) +/- GC, the PTH secretion and calcium set point were evaluated by use of the Cica clamp technique before and after 1 month of treatment. RESULTS: S-osteocalcin, s-total alkaline phosphatase (s-TAP) and s-carboxyterminal cross-linked telopeptide of type I collagen (s-ICTP) were elevated in all groups. The levels of urine pyridinoline (Pyr) and s-albumin-corrected calcium (s-AlbCorrCa2+) were elevated in patients with active disease and patients treated with GC. S-PTH and s-phosphate were within normal ranges. S-TAP, s-ICTP, Pyr and s-AlbCorrCa2+ correlated positively with indices of disease activity. In the subgroups undergoing the Cica clamp technique, no difference in PTH responsiveness of B-Ca2+ was unveiled. CONCLUSION: Neither active disease nor GC therapy appears to induce secondary hyperparathyroidism, nor is there an alteration in PTH responsiveness of B-Ca2+ in patients with RA. The increased levels of markers of type I collagen metabolism (s-ICTP, Pyr) and s-AlbCorrCa2+ in patients with active disease and patients treated with GC may be a result of increased degradation in synovium, cartilage and bone due to the inflammatory process.

Anti-Inflammatory Agents↗

PubMed2001

Autometallographic tracing of bismuth in human brain autopsies.

For decades, drugs containing bismuth have been used to treat gastrointestinal disorders. Although a variety of adverse effects, including neurological syndromes, have been recorded, the biological/toxicological effects of bismuth ions are far from disclosed. Until recently, only quantitative assessments were possible, but resent research has made histochemical tracing of bismuth possible. The technique involves silver enhancement of bismuth crystallites by autometallography (AMG). In the present study, the localization of bismuth was traced by AMG in sections of paraffin-embedded brain tissue obtained by autopsy from 6 patients suffering from bismuth intoxication in a period ranging from 1975 through 1977. Tissue was analyzed at light and electron microscopical levels, and the presence of bismuth further confirmed by proton-induced x-ray emission (PIXE). Clinical data and bismuth concentrations in blood, cerebellum, and thalamus were measured by atomic absorption spectrophotometry (AAS) and are reported here. Histochemical analyses demonstrate that bismuth accumulated in neurons and glia cells in the brain regions examined (neocortex, cerebellum, thalamus, hippocampus). Cerebellar blood vessels stained most intensely. The PIXE and AAS data correlated with the histochemical staining patterns and intensities. At the ultrastructural level, bismuth was found to accumulate intracellularly in lysosomes and extracellularly in the basement membranes of some vessels.

Aged↗

PubMed2001

Quantitative magnetic resonance imaging as marker of synovial membrane regeneration and recurrence of synovitis after arthroscopic knee joint synovectomy: a one year follow up study.

OBJECTIVES: By repeated magnetic resonance imaging (MRI) to study synovial membrane regeneration and recurrence of synovitis after arthroscopic knee joint synovectomy in patients with rheumatoid arthritis (RA) and other (non-RA) causes of persistent knee joint synovitis. METHODS: Contrast enhanced MRI was performed in 15 knees (nine RA, six non-RA) before and one day, seven days, two months, and 12 months after arthroscopic synovectomy. Synovial membrane volumes, joint effusion volumes, and cartilage and bone destruction were assessed on each MRI set. Baseline microscopic and macroscopic assessments of synovitis and baseline and follow up standard clinical and biochemical examinations were available. RESULTS: Synovial membrane and joint fluid volumes were significantly reduced two and 12 months after synovectomy. However, MRI signs of recurrent synovitis were already present in most knees at two months. No significant differences between volumes in RA and non-RA knees were seen. Synovial membrane volumes at two months were significantly inversely correlated with the duration of clinical remission, for all knees considered together (Spearman's correlation r(s)=-0.67; p<0.05), for RA knees (r(s)=-0.76; p<0.05), and for non-RA knees (r(s)=-0.83; p<0.05). Baseline volumes were not significantly correlated with clinical outcome. Only three knees (all RA) showed erosive progression. The rate of erosive progression was not correlated with MRI volumes or with clinical or biochemical parameters. CONCLUSION: The synovial membrane had regenerated two months after arthroscopic knee joint synovectomy and despite significant volume reductions compared with baseline it often showed signs of recurrent synovitis. MRI seems to be valuable as a marker of inflammation, destruction and, perhaps, as a predictor of therapeutic outcome in arthritis.

Adult↗

PubMed2001

Histochemical tracing of bismuth in Helicobacter pylori after in vitro exposure to bismuth citrate.

BACKGROUND: Bismuth-containing drugs are widely used in the treatment of Helicobacter pylori associated peptic ulcer. The mechanism of action of bismuth salts is, however, not fully understood, and at present no histochemical techniques for the demonstration of bismuth in H. pylori are available. The aims were to present a histochemical method for the detection of bismuth in H. pylori and to demonstrate bismuth uptake in H. pylori after in vitro exposure to bismuth citrate. METHODS: H. pylori cultures (the strain used in this study was CCUG 17874), were exposed to bismuth citrate at different concentrations (0, 4.6, 80, 200 microM) and for different lengths of time (0 min, 15 min, 1 h, 24 h, 48 h). The samples were fixed in glutaraldehyde, centrifuged, and exposed to autometallographic (AMG) development in order to detect bismuth histochemically. RESULTS: A detailed protocol on the AMG bismuth technique on H. pylori exposed to bismuth in vitro is given. This method results in easily detectable AMG grains of silver enhanced bismuth particles at the electron microscopical level, and shows that bismuth accumulates in H. pylori, predominantly near the wall of the bacteria. Bismuth uptake is followed by bacterial degeneration. CONCLUSION: The present technique with its ability to trace bismuth constitutes a valuable tool in the efforts of clarifying the mechanism of action of bismuth on H. pylori, and supports the notion that bismuth has an antimicrobial activity in itself.

Anti-Ulcer Agents↗

PubMed2000

Tissue uptake of bismuth from shotgun pellets.

Shotgun pellets containing bismuth have been suggested to be less environmentally toxic than those containing other metals. We sought to find if bismuth from shotgun pellets embedded within an animal enters the tissues of that animal. Five bismuth-containing shotgun pellets were placed intraperitoneally into adult mice. Four or 9 weeks later the tissue distribution of bismuth was examined histologically using silver lactate autometallography. Bismuth was seen in the nervous system of the mice, either in cells with processes outside the nervous system or in cells not protected by the blood-brain barrier. Bismuth was also seen in the kidney, liver, spleen, and lung. The amount of bismuth within tissues varied widely between animals at both time intervals. Bismuth from shotgun pellets enters the tissues of mice, with some mice taking up more bismuth than others. Some animals wounded with bismuth pellets are therefore likely to accumulate large amounts of potentially toxic bismuth in their tissues.

Animals↗

PubMed2000

Histochemical differentiation of autometallographically traceable metals (Au, Ag, Hg, Bi, Zn): protocols for chemical removal of separate autometallographic metal clusters in Epon sections.

Nano-sized clusters of gold atoms, or alternatively silver, mercury, bismuth, or zinc sulphide/selenide molecules, can be autometallographically silver-enhanced by being placed in a developer containing reducing molecules and silver ions, i.e. an autometallographic developer. A specific recipe has been worked out for each autometallographically traceable metal, and in cases where two or more autometallographic catalysts are present in the same section it is feasible to distinguish one from the other by chemical removal of one or the other of the metals. In the present study we present protocols that allow differentiation and control of specificity of the established autometallographically detectable metals. It is recommended to implement a multi-element analysis, e.g. proton-induced X-ray emission on a few samples to secure the histochemical data.

Animals↗