Enzyme histochemical study of germanium dioxide-induced mitochondrial myopathy in rats.
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The purpose of this study were 1) to determine the earliest pathological changes of germanium dioxide (GeO2)-induced myopathy; 2) to determine the pathomechanism of GeO2-induced myopathy; and 3) to determine the minimal dose of GeO2 to induce myopathy in rats. One hundred and twenty five male and female Sprague-Dawley rats, each weighing about 150 gm, were divided into seven groups according to daily doses of GeO2. Within each group, histopathological studies were done at 4, 8, 16, and 24 weeks of GeO2 administration. Characteristic mitochondrial myopathy was induced in the groups treated daily with 10 mg/kg of GeO2 or more. In conclusion, the results were as follows: 1) The earliest pathological change on electron microscope was the abnormalities of mitochondrial shape, size and increased number of mitochondria; 2) The earliest pathological change on light microscope was the presence of ragged red fibers which showed enhanced subsarcolemmal succinate dehydrogenase and cytochrome c oxidase reactivity; 3) GeO2 seemed to affect the mitochondrial oxidative metabolism of muscle fibers; 4) GeO2 could induce mitochondrial myopathy with 10 mg/kg of GeO2 for 4 weeks or less duration in rats. (+info)
Detection of nonthermal melting by ultrafast X-ray diffraction.
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Using ultrafast, time-resolved, 1.54 angstrom x-ray diffraction, thermal and ultrafast nonthermal melting of germanium, involving passage through nonequilibrium extreme states of matter, was observed. Such ultrafast, optical-pump, x-ray diffraction probe measurements provide a way to study many other transient processes in physics, chemistry, and biology, including direct observation of the atomic motion by which many solid-state processes and chemical and biochemical reactions take place. (+info)
Determination of germanium in human specimens: comparative study of atomic absorption spectrometry and microwave-induced plasma mass spectrometry.
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The determination methods of germanium (Ge) in biological specimens such as blood plasma, erythrocytes, urine, hair, nail, and other organs were established using graphite furnace atomic absorption spectrometry (GFAAS) and microwave-induced plasma mass spectrometry (MIP-MS). The detection limits of Ge standard solution were 3 ng/mL with GFAAS and 0.05 ng/mL with MIP-MS. The detection limits in organ samples depended on the type of samples and sampling amounts: 3-30 ng/g by GFAAS and 0.05-0.5 ng/g by MIP-MS. The sensitivity of GFAAS was lower than that of MIP-MS; however, it was adequate for determining Ge concentrations in specimens from patients who had ingested Ge. Samples were digested by a simple wet-ashing procedure using nitric acid and perchloric acid. To avoid the interfering effects of coexisting elements and perchloric acid residue, an extraction method using organic solvent was tried. When using MIP-MS, extraction was not necessary; however, both dilution and addition of an internal standard were needed. Special attention was required for iron-rich samples because a molecular ion of 56Fe16O was observed at nm/z72 where 2Ge was monitored. The results of Ge concentrations in human samples obtained by these methods agreed well. Interfering effects of perchloric acid, which was used for digestion and which remained in samples, were observed in both methods. Hair and nail samples from people who had ingested Ge were useful for monitoring Ge in the body. Hair samples were useful for determining past exposure to Ge when the distribution patterns from the scalp to the end of the strand were analyzed. In control subjects, Ge concentrations in the listed specimens and organs were lower than 0.1 microg/g or mL, and these low levels of Ge were able to be determined by MIP-MS in combination with the extraction method. (+info)
Epidemiological survey of workers exposed to inorganic germanium compounds.
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OBJECTIVES: To assess occupational exposure to inorganic germanium (Ge) in workers from a producing plant, and to assess the health of these workers, with a special focus on respiratory, kidney, and liver functions. METHODS: Cross sectional study of 75 workers exposed to Ge and 79 matched referents. Exposure was characterised by measuring air and urine concentrations of the element during a typical working week, and health was assessed by a questionnaire, clinical examination, lung function testing, chest radiography, and clinical chemistry in serum and urine, including high and low molecular weight urinary proteins. RESULTS: Airborne concentrations of Ge (inhalable fraction) ranged from 0.03 to 300 micrograms/m, which was reflected by increased urinary excretion of Ge (0.12-200 micrograms/g creatinine, after the shift at the end of the working week). Lung, liver, and haematological variables were not significantly different between referents and workers exposed to Ge. A slightly higher urinary concentration of high molecular weight proteins (albumin and transferrin) was found in workers exposed to Ge, possibly reflecting subclinical glomerular changes. No relation was found between the intensity or duration of exposure and the urinary concentration of albumin. No difference between referents and workers exposed to Ge was found for other renal variables. CONCLUSIONS: Measurement of urinary Ge can detect occupational exposure to inorganic Ge and its compounds. It is prudent to recommend the monitoring of renal variables in workers exposed to Ge. (+info)
L-Arginine treatment may prevent tubulointerstitial nephropathy caused by germanium dioxide.
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BACKGROUND: Long-term oral ingestion of germanium dioxide (GeO2) causes progressive renal failure derived from tubulointerstitial nephropathy in humans and animals. The characteristic of GeO2-induced nephropathy is the renal tissue injury persisting for a long time, even after cessation of GeO2 ingestion. However, a treatment that can suppress the long-lasting renal tissue injury has not yet been established. METHODS: Using the methods of immunohistochemistry and reverse transcription-polymerase chain reaction, we examined the expression of ED1-positive cells (macrophages/monocytes), transforming growth factor (TGF)-beta1 mRNA and protein and collagen type IV mRNA and protein in the kidneys of rats with GeO2-induced nephropathy. Concomitantly, the effects of L-arginine treatment on their expression was explored in the kidneys of rats with GeO2-induced nephropathy. RESULTS: Chronic administration of GeO2 caused tubulointerstitial nephropathy characterized by leukocyte invasion into the enlarged tubulointerstitial space in rats. The expression of ED1-positive cells, TGF-beta1 protein and collagen type IV protein was markedly increased in the tubulointerstitium of the renal cortex from rats with GeO2-induced nephropathy. Similarly, TGF-beta1 and collagen type IV mRNA were significantly enhanced in the renal cortex of rats with GeO2-induced nephropathy. A small number of tubulointerstitial cells expressing TGF-beta1 protein were also observed in the renal cortex of rats with GeO2-induced nephropathy. However, L-arginine treatment led to a parallel decrease in the expression of ED1-positive cells, TGF-beta1 mRNA and collagen type IV mRNA and protein in rats with GeO2-induced nephropathy. CONCLUSIONS: In general, collagen synthesis is driven by TGF-beta1 in the fibrotic process associated with a variety of renal disorders. TGF-beta1 is secreted by TGF-beta1 producing cells such as macrophages, fibroblasts and myofibroblasts. Thus, the present study indicates that the expression of collagen type IV may be mediated by TGF-beta1 released from invading macrophages and, to a lesser extent, released from tubulointerstitial cells, presumably fibroblasts and/or myofibroblasts in GeO2-induced nephropathy. L-Arginine treatment inhibits collagen type IV synthesis possibly by suppressing macrophage invasion and the resultant TGF-beta1 expression in this nephropathy. L-Arginine treatment may be beneficial in the prevention of tubulointerstitial fibrosis, which is considered to be the terminal stage of GeO2-induced nephropathy. (+info)
Expression of silicatein and collagen genes in the marine sponge Suberites domuncula is controlled by silicate and myotrophin.
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The major skeletal elements in the (Porifera) sponges, are spicules formed from inorganic material. The spicules in the Demospongiae class are composed of hydrated, amorphous silica. Recently an enzyme, silicatein, which polymerizes alkoxide substrates to silica was described from the sponge Tethya aurantia. In the present study the cDNA encoding silicatein was isolated from the sponge Suberites domuncula. The deduced polypeptide comprises 331 amino acids and has a calculated size of Mr 36 306. This cDNA was used as a probe to study the potential role of silicate on the expression of the silicatein gene. For these studies, primmorphs, a special form of aggregates composed of proliferating cells, have been used. It was found that after increasing the concentration of soluble silicate in the seawater medium from around 1 microM to approximately 60 microM, this gene is strongly upregulated. Without additional silicate only a very weak expression could be measured. Because silica as well as collagen are required for the formation of spicules, the expression of the gene encoding collagen was measured in parallel. It was also found that the level of transcripts for collagen strongly increases in the presence of 60 microM soluble silicate. In addition, it is demonstrated that the expression of collagen is also upregulated in those primmorphs which were treated with recombinant myotrophin obtained from the same sponge. Myotrophin, however, had no effect on the expression of silicatein. From these data we conclude that silicate influences the expression of the enzyme silicatein and also the expression of collagen, (via the mediator myotrophin). (+info)
Semiconductor camera for detection of small tumors.
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Early detection of small tumors (approximately 3 mm) with only a moderate uptake ratio is often difficult because of poor statistics and a small signal-to-background ratio. The detection capability of a germanium semiconductor camera is analyzed to show that a very large number of counts is required even when the spatial resolution is matched to the size of the tumor. A potential enhancement of statistics using the tissue-scattered gamma rays is discussed based on the superior energy resolution of the semiconductor. (+info)
Propagermanium reduces atherosclerosis in apolipoprotein E knockout mice via inhibition of macrophage infiltration.
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Monocyte chemoattractant protein-1 (MCP-1), which binds to C-C chemokine receptor 2, has been implicated as the primary source of monocyte chemoattractant function in the early stages of atherosclerosis. Recently, propagermanium, a drug used clinically for the treatment of chronic hepatitis in Japan, has been shown to inhibit C-C chemokine receptor 2 function and suppress monocyte/macrophage infiltration in vitro and in vivo. Given the importance of monocyte infiltration in atherogenesis, the inhibition of it by propagermanium might prevent atherosclerosis. Apolipoprotein E knockout (apoE-KO) mice were fed an atherogenic high cholesterol diet with or without 0.005% propagermanium for 8 or 12 weeks. Although the plasma lipid levels were unchanged by the drug treatment, atherosclerotic lesion area in the aortic root was reduced by 50% in the drug-treated apoE-KO mice compared with the nontreated apoE-KO mice after 8 weeks of cholesterol feeding (0.62+/-0.12 versus 1.27+/-0.07 mm2, respectively; P<0.01). Moreover, the accumulation of macrophages in the lesions was markedly reduced in the drug-treated group (macrophage positive area, 0.23+/-0.06 mm2 [drug-treated group] versus 0.67+/-0.07 mm2 [control group]; P<0.01). After 12 weeks of cholesterol feeding, atherosclerotic lesion formation in the aortic root and in the descending thoracic aorta was significantly reduced in the drug-treated group. Inhibition of macrophage infiltration by propagermanium prevented the formation of atherosclerotic lesions in apoE-KO mice. This drug may serve as a therapeutic tool for the treatment of atherosclerosis. (+info)