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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 56 (1984), S. 315-325 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Ice single crystals are superheated by a pressure jump. Their optical homogeneity is examined by elastic light scattering in order to obtain information about the thermodynamic state in the bulk of the sample. The intensity of the scattered light after the pressure jump remains first unchanged. Only after a time lag τ a steep intensity increase is observed. The dependence of τ on the superheating, on sample size, on the position of the scattering volume in the sample, on crystal orientation, on the scattering angle and on the crystal quality is examined. τ depends only on superheating and crystal quality within experimental sensitivity. After a superheating of more than 5°C the optical appearance of ice is like opalescent glass. The observations are compatible with the assumption that the ice has been superheated with respect to the melt and that homogeneous nucleation occurs in the metastable state. The equilibrium curve iceI h —water has been determined.
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  • 2
    ISSN: 1432-1246
    Keywords: Pesticides ; Hexachlorocyclohexane ; Lindane ; Health supervision ; Benzenehexachloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sixty male workers in a lindane (y-hexachlorocyclohexane)-producing factory were examined with regard to health in comparison with an external control group of 20 clerks. Case history, physical examination, neurologic status, and ECG revealed no significant differences between groups. However, the following significant differences in clinical-chemical blood tests were ascertained: higher polymorphonuclear leukocyte count, lower lymphocyte count, higher reticulocyte count, lower prothrombin (Quick's) test, and lower blood concentrations of creatinine and uric acid. No significant differences were observed in total red and white blood cell as well as platelet counts, hemoglobin content, the other counts of differential blood picture, γ-GT, GOT, GPT, LDH, cholinesterase, triglycerides, cholesterol, and urea. In spite of a pronounced exposure to the α-, β-, and γ-isomers of hexachlorocyclohexane, no signs of severe impairment of health were observed; only small deviations in some laboratory tests were found having no pathologic significance. However, biological monitoring and health supervision of HCH-exposed workers should be carried out.
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  • 3
    ISSN: 1432-1246
    Keywords: Pesticides ; Hexachlorocyclohexane ; Lindane benzenehexachloride ; Sex hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a lindane (γ-hexachlorocyclohexane)-producing factory 54 male workers (mean age 40 years, mean duration of exposure 8 years) were studied with regard to their blood levels of testosterone, LH, and FSH. Twenty clerks of nearly the same age were examined for control purposes in the same way. Serum-LH concentrations of the exposed workers were significantly higher than in controls. Geometric mean values were 8.8 mIU/ml and 5.7 mIU/ml respectively. On the other hand, FSH levels were insignificantly higher. Concerning testosterone concentrations in serum, these were found to be slightly lower in the group of workers than in control persons but this difference could not be proved to be statistically significant. These results indicate certain perturbations in sex hormone regulation probably as a consequence of HCH-exposure. To judge the pathological significance of these alterations further investigation will be necessary.
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  • 4
    ISSN: 1432-1246
    Keywords: Pesticides ; Hexachlorocyclohexane ; Biological monitoring ; Lindane ; Benzenehexachloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a lindane (γ-hexachlorocyclohexane =γ-benzenehexachloride)-producing factory 57 workers were studied with regard to their blood levels of the three hexachlorocyclohexane isomers:α-, β-, andγ-HCH. The TLV-TWA (MAK value 1979) forγ-HCH of 0.5 mg/m3 was not exceeded at any of the workplaces where HCH is synthesized and purified to lindane. Additionally, in some of the workers samples of s.c. adipose tissue were taken for determination of HCH-isomer content. An external group of 20 clerks was examined in the same way for control purposes. In contrast to the control persons, none of whom had HCH-concentrations in serum above the respective detection limits, the values determined in serum of the exposed workers were in the following ranges:α-HCH: 10–273 μg/l,β-HCH: 17–760 μg/l, andγ-HCH: 5-188 μg/l. Of special interest is the observation of a significant increase ofβ-HCH-concentration in serum with the time of employment in lindane production, indicating a pronounced accumulation of this substance in the human organism. Concentrations of this isomer in s.c. adipose tissues were about 300-fold higher than in serum. A significant correlation between both parameters could be established. The results of this study show that adherence to the TLV-TWA ofγ-HCH is not sufficient for control of HCH-exposure. Furthermore, biological monitoring of exposed workers is necessary taking into account the three more important isomersα-, β-, andγ-HCH.
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  • 5
    ISSN: 1432-1246
    Keywords: Pesticides ; Hexachlorocyclohexane ; Lindane neurological findings ; Benzenehexachloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sixty male workers in a lindane (γ-hexachlorocyclohexane) producing factory were examined with regard to functions of nervous system in comparison with two external control groups having no contact with hazardous substances. Examinations of reflexes and sensibility revealed no pathological signs. Mean values of amplitude and frequency of forefinger tremor were found at about 20 μm and 10 Hz respectively without significant differences between groups. Manual skill tested by means of a tracking task was nearly the same in HCH-workers and a control group of dairy workers. On the contrary, a control group of clerks showed significantly better results in the tracking test, a probable consequence of their occupational practice. In electromyography no pathologic patterns were observed. The maximal motor nerve conduction velocity of ulnar nerves showed nearly identical mean values of 59.5 m/s in HCH-workers and controls. Neuromuscular conduction as revealed by distal latencies was not impaired. Furthermore, electroencephalographic recordings taken in spot-checks of HCH-workers and controls did not show any specific pathological signs. Only small abnormalities in rhythm could be observed in some cases of workers as well as of control persons indicating no increased incidence in the HCH exposed group. In conclusion, even after years or decades of occupational HCH exposure, in this study no signs of neurological impairment or perturbation of “neuromuscular function” could be ascertained.
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  • 6
    ISSN: 1432-2013
    Keywords: Endocytosis ; Rat kidney ; Renal lysozyme accumulation ; Dose-dependent inhibition by basic proteins, spermine and basic amino acids ; Microperfusion ; Proximal tubular lysozyme reabsorption ; Dose-dependent inhibition by cytochrome C
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Together the two rat kidneys accumulated a total of 31.7±1.6% of the intravenously injected amount of 7 nmoles egg-white-lysozyme (measured as iodine 125-lysozyme) within 10 min. The low molecular weight protein lysozyme and other basic substances were injected simultaneously in order to evaluate whether these basic substances can inhibit the tenal lysozyme accumulation. The inhibitory effect of various basic compounds was dose-dependent with a maximal reduction of lysozyme accumulation to 11.7±0.8%. The basic substances could be divided into three groups depending upon the micromolar amount injected at which a 50% inhibition was achieved (0.3–1.2 μmoles: cytochrome C, ribonuclease; 10.9 μmoles: spermine; 501–688 μmoles:l-arginine,l-lysine). The neutral myoglobin had no effect on renal lysozyme accumulation. The inhibitory potency appeared to increase with increasing molecular weight and pI value of the substances tested. Microperfusion experiments of proximal convoluted tubules of rat kidney revealed that luminal reabsorption of the basie lysozyme can be inhibited by the basic protein cytochrome C in a dose-dependent fashion. In these experiments the perfusion solution contained 57 μmol·l−1 lysozyme, an intratubular lysozyme concentration at which the tubular lysozyme reabsorption was found to be about 80% saturated. A 50% inhibition of the tubular endocytic lysozyme reabsorption was achieved at a cytochrome C concentration of 102 μmol·l−1.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 401 (1984), S. 333-339 
    ISSN: 1432-2013
    Keywords: Low molecular weight protein ; Lysozyme ; Renal reabsorption, accumulation and degradation ; Tyrosine ; Gentamicin ; Inhibition of lysozyme degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous renal clearance studies provided quantitative data concerning renal reabsorption of proteins while the simultaneous processes of renal accumulation and degradation remain, to a great extent, insufficiently investigated. Thus, it was the aim of this study to measure renal reabsorption of egg-white lysozyme at various lysozyme concentrations and to relate the corresponding accumulation and degradation of lysozyme to the lysozyme transport rates in intact rats and isolated perfused rat kidneys. Lysozyme (with125I-lysozyme in certain experiments), was continuously infused i.v. or added to the perfusate to achieve plasma (or perfusate) concentrations of lysozyme (PLY) of approximately 50, 500 or 1000 mg·l−1 for periods of time varying between 3 and 120 or 150 min. Clearances of inulin and lysozyme or the total content of radioactivity and the trichloroacetic acid (TCA)-soluble radioactivity in the kidney tissue were determined at the end of clearance or accumulation periods. Additionally the perfusate concentration of the metabolite tyrosine was measured by high performance liquid chromatography (HPLC). The reabsorption rates of lysozyme (TLY) were concentration-dependent in both intact rats and isolated perfused rat kidney. After 25 min of lysozyme infusion, the lysozyme reabsorption rates amounted to 37, 245 and 331 μg·min−1·g−1 kidney at the above lysozyme concentrations. After the same infusion time, the accumulation rates of lysozyme were 8, 59 and 118 μg·min−1·g−1 kidney. The difference between the transport rate and accumulation rate should represent the renal degradation rate of lysozyme. The renal accumulation and degradation of lysozyme appeared to increase in a time- and concentration-dependent manner. The renal lysozyme degradation is of limited capacity as shown by measuring directly the release of the amino acid tyrosine by using HPLC. Renal degradation of lysozyme was almost totally inhibited by gentamicin in the presence of significant transport of lysozyme. The results of this study also demonstrate the ability of the rat kidney to reabsorb and accumulate large amounts of the cationic low molecular weight protein lysozyme without ultrastructural changes at plasma concentrations of lysozyme as high as 500 mg·l−1. Transmission electron microscopy indicated an increase in the number of endocytic vesicles and lysosomes at 1000 mg·l−1 plasma concentration of lysozyme after a 30 min infusion.
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  • 8
    ISSN: 1432-2013
    Keywords: Rat kidney ; Clearance studies ; Low molecular weight protein (lysozyme) ; Lysozyme reabsorption ; Dependence on glomerular filtration rate and infusion time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Egg-white-lysozyme was infused into rats intravenously to achieve plasma concentrations of lysozyme (PLy) in the range of 10–3,500 mg·l−1. Concentrations of inulin and lysozyme in plasma and urine samples were determined spectrophotometrically. The glomerular filtration rate (GFR) was measured as clearance of inulin. The lysozyme reabsorption rate (TLy) was calculated as the difference between the filtered load and excreted amount of lysozyme. TLy increased with increasing filtered loads of lysozyme up to 1,000 μg·min−1 whether the increase in load was caused by an increase in PLy or GFR. These TLy were not dependent upon lysozyme infusion time. At lysozyme loads above saturation of reabsorption (1,000 μg·min−1) TLy was dependent on GFR and on the passed time after onset of lysozyme infusion. The results of this study indicated that the transport rate of lysozyme is a function of PLy, GFR and duration of lysozyme delivery to tubular cells.
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