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  • 1
    Electronic Resource
    Electronic Resource
    Integrins on joint cartilage chondrocytes and alterations by ofloxacin or magnesium deficiency in immature rats (1996)
    Springer
    Archives of toxicology 70 (1996), S. 261-270 
    Details
    ISSN: 1432-0738
    Keywords: Key words Quinolone-induced arthropathy ; Magnesium deficiency ; Joint cartilage ; Integrin expression ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Recently, we showed that magnesium deficiency induces lesions in knee joint cartilage from 5-week-old rats that are very similar to ofloxacin-induced cartilage defects. We concluded that quinolone-induced arthropathy is probably due to chelation of magnesium and thus a deficit in functionally available magnesium in joint cartilage (Stahlmann et al. 1995). As magnesium deficiency in joint cartilage could impair chondrocyte-matrix interaction which is mediated by cation-dependent integrin receptors of the β1-subfamily, we investigated integrin expression in joint cartilage from untreated, ofloxacin-treated and magnesium-deficient Wistar rats. With immunohistochemical methods using monoclonal and polyclonal antibodies, we showed that the integrin pattern in joint cartilage from rats corresponded largely to integrin expression described for human cartilage tissue: β1, α1, α3 and αν subunits and the α5β1 and ανβ3 heterodimers were consistently expressed. Joint cartilage lesions were detected in ofloxacin-treated and magnesium-deficient rats. Lesions were more pronounced in the quinolone-treated group. Expression of several integrins was reduced in the vicinity of lesions after oral treatment with 2 × 600 mg ofloxacin/kg for 1 day. Gross-structural lesions (e. g., cleft formation, unmasked collagen fibres) in magnesium-deficient rats were very similar but changes in integrin expression were less pronounced. On the other hand, changes in cartilage matrix composition showed similar alterations in ofloxacin-treated and magnesium-deficient rats: fibronectin deposition in the cartilage matrix increased in both groups while glycosaminoglycan content decreased. In summary, similar defects occur in ofloxacin-treated and magnesium-deficient rats and with immunohistochemical methods subtle differences are demonstrable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050272
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  • 2
    Electronic Resource
    Electronic Resource
    Quinolone-induced arthropathy: exposure of magnesium-deficient aged rats or immature rats, mineral concentrations in target tissues and pharmacokinetics (1997)
    Springer
    Archives of toxicology 72 (1997), S. 26-32 
    Details
    ISSN: 1432-0738
    Keywords: Key words Quinolones ; Magnesium ; Arthropathy ; Rats ; Ofloxacin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Quinolone treatment or magnesium deficiency induce identical cartilage lesions in juvenile rats and show additive arthropathogenic effects. It has been shown previously that neither condition is arthropathogenic in 8-week-old rats. Joint cartilage from aged individuals is rather prone to pathological alterations but information on prolonged quinolone treatment and/or dietarily induced magnesium deficiency in aged animals is not available. We treated magnesium-deficient (n = 9) aged Wistar rats (age 15 months) and age-matched controls with daily doses of 600 mg ofloxacin/kg body wt. by gastric intubation for 28 days. Further groups of magnesium-deficient and control rats (n = 9 and n = 10, respectively) received the vehicle only. Peak plasma concentrations of ofloxacin in adult rats were 20.5 ± 5.6 mg/l (mean ± SD) following treatment with a single dose of 600 mg/kg body wt. At the end of the experiment the degree of magnesium deficiency was most pronounced in plasma (Mg2+-def., 0.33 ± 0.12 mmol/l; control, 0.97 ± 0.08 mmol/l) and less pronounced in sternal cartilage (Mg2+-def., 10.8 ± 3.6 mmol/kg dry wt; control, 13.3 ± 2.8 mmol/kg dry wt), whereas the magnesium concentration in femoral bone remained unchanged (Mg2+-def., 201 ± 13 mmol/kg dry wt; control, 204 ± 11 mmol/kg dry wt). Histological investigation of the knee joints revealed no cartilage lesions following ofloxacin treatment, magnesium deficiency or a combination of both conditions. By contrast, cartilage lesions such as scars and erosions of the joint surface, chondrocyte clusters within acellular areas of the cartilage matrix and persisting clefts were detectable in knee joints from 7 of 10 adult rats (age 9 months) which had been treated with 4 × 600 mg fleroxacin/kg body wt. at 5 weeks of age. Mean plasma concentration of fleroxacin in juvenile rats was approx. 50 mg/l between 1.5 and 6 h after dosing and the drug was still detectable in plasma 48 h after dosing (0.4 ± 0.1 mg/l). Our data indicate that joint cartilage in aged rats is not altered by a 4-week quinolone treatment, even during magnesium deficiency. Cartilage lesions in adult rats were only detectable if the animals had been treated during the sensitive phase at 5 weeks postnatally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050464
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  • 3
    Electronic Resource
    Electronic Resource
    Polyamines and osmoregulation in Escherichia coli (1979)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 5 (1979), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1979.tb03240.x
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  • 4
    Electronic Resource
    Electronic Resource
    Femtosecond near-field spectroscopy of a single GaAs quantum wire (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 3500-3502 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Quasi-two-color femtosecond pump and probe spectroscopy and near-field scanning optical microscopy are combined to study the carrier dynamics in single semiconductor nanostructures. In temporally, spectrally, and spatially resolved measurements with a time resolution of 200 fs and a spatial resolution of 200 nm, the nonlinear change in reflectivity of a single quantum wire is mapped in real space and time. The experiments show that carrier relaxation in a single quantum wire occurs on a 100 fs time scale at room temperature. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125368
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  • 5
    Electronic Resource
    Electronic Resource
    Near-field photocurrent imaging of the optical mode profiles of semiconductor laser diodes (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 1463-1465 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The potential of near-field photocurrent spectroscopy for direct imaging of mode profiles of submicron-sized waveguides in optoelectronic devices is demonstrated. The technique combines the submicron spatial resolution of near-field optics with tunable laser excitation, allowing for selective investigation of the waveguide properties of the device structure. Experiments on InGaAs/AlGaAs high-power laser diodes with different waveguide designs provide direct visualization of the effect of the waveguide design on (i) the number of guided modes and (ii) the spatial profile of both fundamental and higher-order modes. The technique thus provides a sensitive tool for nondestructive in situ analysis of waveguide properties in optoelectronic devices. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1342206
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  • 6
    Electronic Resource
    Electronic Resource
    Interrelations between polyamines and phospholipids in Escherichia coli (1979)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 5 (1979), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1979.tb03365.x
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  • 7
    Electronic Resource
    Electronic Resource
    Antigen stool test for assessment of Helicobacter pylori infection in patients with upper gastrointestinal bleeding (2003)
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 17 (2003), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : Re-bleeding of Helicobacter pylori-associated peptic ulcer disease is reduced by H. pylori eradication.Aim : To validate a non-invasive test, the Premium Platinum HpSA™ stool test, in patients with upper gastrointestinal bleeding.Methods : Stool samples of consecutive patients with relevant bleeding from gastric or duodenal ulcers or erosions were collected at initial endoscopy and during the following week. Samples were assessed using the HpSA™ test. H. pylori status was defined by three biopsy-based reference methods: culture, rapid urease test and histology. It was positive if culture was positive or if rapid urease test and histology were positive.Results : One hundred and fourteen patients (mean age, 66 years) were included. In accordance with the definition, 56 (49%) were H. pylori positive. The sensitivity and specificity of the first stool sample were 84% and 90%, respectively. The respective values for two samples from consecutive days were 91% and 86%. In comparison with a serum immunoglobulin G antibody enzyme-linked immunoabsorbent assay, the HpSA™ test showed superior specificity.Conclusions : The diagnostic accuracy, in particular the sensitivity, of the HpSA™ stool test is reduced by upper gastrointestinal bleeding. The positive predictive value of 89%, however, justifies the initiation of eradication therapy on the basis of a positive stool test. A negative test result should be confirmed by a further diagnostic method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.2003.01548.x
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of Magnesium Deficiency on Magnesium and Calcium Content in Bone and Cartilage in Developing Rats in Correlation to Chondrotoxicity (1997)
    Springer
    Calcified tissue international 61 (1997), S. 230 -238 
    Details
    ISSN: 1432-0827
    Keywords: Key words:Magnesium — Calcium — Bone — Cartilage — Quinolones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Quinolone-induced arthropathy has been described in juvenile rats between 3 and 6 weeks of age, but not in adult rats. The mechanism of this chondrotoxic effect is probably related to the Mg2+-chelating properties of the drugs, since identical cartilage lesions were observed in magnesium-deficient juvenile rats without quinolone treatment. However, the reasons for the phase-specificity of the effect are unknown. In the present study, we fed a magnesium-deficient diet to Wistar rats at different postnatal developmental stages. Cartilage lesions were only observed in magnesium-deficient rats between 3 and 5 weeks of age, but not in rats receiving the magnesium-deficient diet during weeks 5 to 8, weeks 8 to 11, or months 15 to 16. The formation of cartilage lesions was not related to the magnesium concentration in plasma, since magnesium concentrations in plasma were similarly reduced in rats with and without cartilage lesions. However, chondrotoxicity correlated with magnesium content in articular cartilage. In articular cartilage (articular and epiphyseal cartilage in immature rats) and bone, magnesium content was more reduced in rats receiving the magnesium-deficient diet between 3 and 5 weeks of age as compared with rats receiving the magnesium-deficient diet during weeks 8 to 11 postnatally. It was not possible to reduce the magnesium content in bone tissue of 15-month-old Wistar rats, which suggests a lower magnesium turnover in aged rats. Magnesium content in epiphyseal cartilage of 2-week-old rats (total femoral head) was 41.9 ± 16.9 mmol/kg dry weight. The magnesium content in joint hyaline cartilage was significantly lower in 4-week-old rats (19.5 ± 3.6 mmol/kg dry weight) and increased subsequently again to 48.5 ± 9.2 mmol/kg dry weight (mean ± SD; n= 8 to 16). Increase of the magnesium content in femoral bone between weeks 4 and 6 postnatally was less pronounced (139 ± 10 and 175 ± 15 mmol/kg dry weight, respectively). Taken together, these data show that in 4-week-old rats, magnesium concentration in joint hyaline cartilage is significantly lower than at other times during postnatal development. Only at this developmental stage can cartilage lesions be induced by feeding rats a magnesium-deficient diet. This period correlates well with the sensitive phase of immature rats toward the chondrotoxic action of quinolones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900328
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  • 9
    Electronic Resource
    Electronic Resource
    Enzyme histochemistry of malignant T cell lymphoma due to chronic magnesium deficiency in rats (1984)
    Springer
    Histochemistry and cell biology 80 (1984), S. 183-186 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lymphocytes of the rat thymus can be grossly differentiated by their cell membrane-bound proteinases. Subcapsular thymocytes lack aminopeptidase A (APA) and AMP and γ-glutamyltranspeptidase (GGT). Cortical thymocytes show a high activity of APA but no APM and no GGT. Medullar thymocytes posses a high GGT and APM activity but are free of APA. Under Mg deficiency, the APA-negative subcapsular thymocytes are reduced. In lymphoma and beginning lymphoma, APA, APM and GGT are absent. In lymphoma, the alkaline phosphatase activity is increased. Differences are found for dipeptidylpeptidase IV (DPP IV). In some lymphoma, its activity is reduced, in others the DPP IV activity is increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679994
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  • 10
    Electronic Resource
    Electronic Resource
    Health effects of traffic noise (1980)
    Springer
    International archives of occupational and environmental health 47 (1980), S. 179-190 
    Details
    ISSN: 1432-1246
    Keywords: Biochemical reactions ; Blood circulation ; Cardiovascular disease ; Mg deficiency ; Psychical tension ; Traffic noise ; Working quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 57 test persons having worked 1 day under traffic noise (Leq= 85 dB(A) and 1 day without noise (Leq 〈 50 dB(A), blood pressure and pulse frequency were measured at 1 h intervals and total urine was collected during working hours. Additionally, blood was sampled at the end of each working day. Psychological parameters were assessed by means of questionnaires. Statistically significant reactions to noise were found in the following fields: 1. Ergnomics—decrease of working quality; 2. Psychology—increase of psychical tension; 3. Blood circulation—increase of blood pressure and pulse frequency; 4. Biochemistry—increase of epinephrine, cAMP, urine and serum Mg, protein, cholesterol plus decrease of erythrocyte Na, and renin. Hypothetical mechanisms of the action of traffic noise are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00716376
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