Toxic and fibrogenic effects of plasmochemical silicon nitride

It is found that very finely divided silicon nitride made by plasmochemical synthesis has more pronounced general toxicity and cytotoxicity than coarse material made by nitriding silicon. It is proposed to reduce the maximum permissible concentration for ultrafine silicon nitride powder from 6 mg/m³ to 1 mg/m³.Kiev Medical Institute. Institute of Problems in Materials Science, Academy of Sciences of the Ukraine, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1–2, pp. 117–119, January–February, 1994.     

Toxic effects of capsaicin on keratinocytes and fibroblasts

We studied the frequency of the coreceptor CCR5 gene delta 32 mutation on 1,836 DNA samples originating from ten French regions. This mutation confers, in the homozygous state, resistance to HIV-1 infection. For the whole territory, the mean percentage presence of the delta 32 mutation is 9.2%. The mutation is statistically more frequent in the north (11.2%) than in the south (6.3%) of the country; this differentiation corresponds probably to a gradient of decreasing frequencies of the delta 32 mutation in Europe.     

Treatment of low back pain and sciatica by intradiskal injection of chymopapain

Single injections of 50 mug estradiol-17beta (E2beta) into overiectomized sheep caused biphasic changes in plasma luteinizing hormone (LH). An initial 8-h period of LH inhibition was followed by a period (12-20 h after E2beta) of facilitated LH release. Pituitary LH responsiveness to small dosages of synthetic gonadotropin-releasing hormone (GnRH) was tested repeatedly at 2-h intervals during the time periods when plasma LH was inhibited and when it was facilitated. Reduced sensitivity to GnRH (91% decrease) characterized only the initial 4 h of the inhibitory period, suggesting that E2beta suppressed endogenous LH-releasing factor (LRF) during the latter part of the inhibitory period. Hypersensitivity (2-fold increase) to GnRH was briefly observed at the beginning of the period of E2beta-facilitated LH release. This transient and modest hypersensitivity does not completely account for the very large E2beta-induced increases in plasma LH. Therefore, E2beta probably increased endogenous LRF during the period of facilitated LH release.     

Toxic effects of quinolone antibacterial agents on the musculoskeletal system in juvenile rats

Quinolone antibacterial agents have adverse effects on the musculoskeletal system in humans, consisting mainly of myalgia and arthralgia, and additionally of tendon disorders and rhabdomyolysis. The present study was conducted to examine the toxic effects of quinolones on the musculoskeletal system in juvenile rats using light microscopy, 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry and electron microscopy. Single oral administration of 900 mg/kg pefloxacin (PFLX) or levofloxacin (LVFX) was found to induce lesions in the muscle + fascia, tendon + sheath, and synovial membrane, in addition to articular cartilage in the fore- and hindlimbs. Articular cartilage lesions were not necessarily associated with changes in the muscle, tendon, and synovial membrane, or the reverse. Among all lesions, the ankle and elbow showed the highest incidence and severity. Changes were more severe in the PFLX than in the LVFX group. Lesions in the muscle + fascia, tendon + sheath, and synovial membrane were similar and characterized by edema and increased number of mononuclear cells, many of which were positively stained with BrdU, as well as vascular endothelial cells in the Achilles tendon sheath and synovial membrane in the ankle. Electron microscopic examination revealed an increased number of fibroblasts and macrophages and collagen deposition in the matrix of the synovial membrane and tendon sheath. Capillary endothelial cells were hypertrophied, increased in number, and stratified. These results suggest that quinolones have toxic potentials in the muscle, tendon, and synovial membrane in addition to articular cartilage, and that local vascular hyperpermeability may contribute to the development of these lesions.     

Toxic nodular goiter. Toxic adenoma and toxic multinodular goiter

Solitary toxic adenoma and toxic multinodular goiter are very common forms of thyrotoxicosis around the world. Advances in molecular biology and genetics have led to new insights into the pathogenesis of these disorders. Current theories on autonomy in the thyroid are discussed in this article. The therapeutic roles of surgery, radioiodine ablation, and percutaneous ethanol administration also are reviewed.     

Toxic effects of deoxynivalenol on ribosomes and tissues of the spring wheat cultivars Frontana and Casavant

The toxic effects of the Fusarium graminearum trichothecene toxin deoxynivalenol were determined on ribosomes and leaf tissues of the fusarium head blight-resistant spring wheat cultivar Frontana and the susceptible spring wheat cultivar Casavant. The use of a poly-U-directed 14C-phenylalanine and deoxynivalenol ribosome-binding assays provided evidence of resistance to the protein-synthesis inhibition effects of deoxynivalenol in the head blight-resistant cultivar Frontana. This is probably due to the existence of a mutation in the peptidyl transferase. This cultivar also exhibited resistance to the membrane-damaging properties of this toxin compared to the other cultivar. This report summarizes the evidence for various kinds of "trichothecene tolerance" mechanisms in fusarium head blight-resistant wheat genotypes.     

一次性筷子、牙签及纸杯浸提液对小鼠L-929细胞的毒性作用

目的:评价一次性筷子、牙签及纸杯浸提液对小鼠L-929细胞的毒性作用.方法:参照国家标准,制备一次性筷子、牙签及纸杯等样品浸提液,采用样品浸提液配制培养液培养小鼠L-929细胞,在光镜下观察细胞生长形态,采用细胞计数法计算细胞失贴壁率,采用WST-1法测定细胞活性并计算细胞增殖度.结果:与对照组相比,采用浸提液配制的细胞培养液培养细胞4 d或7 d后,各组细胞出现凋亡或坏死征象,细胞失贴壁率明显升高(P<0.05),细胞活性及细胞增殖度明显下降(P<0.05).结论:一次性筷子、牙签及纸杯用具等能影响L-929细胞生长及增殖,可能具有潜在的毒性作用.     

Efficacy of Biofilms under Toxic Conditions

Response of biofilms to toxic compounds has been modeled using Monod-type inhibition kinetics. Biofilm inhibition due to substrate, secondary substrate, and product is considered. For biofilm inhibition due to substrate and secondary substrate with high inhibitory substances, the model predicted the biofilm effectiveness factor to be higher than unity. On the other hand, for slightly inhibitory substances, substrate limitations within the biofilm due to mass transfer resistance resulted in a reduction in biofilm effectiveness factor as its thickness increased. In case of product inhibition, the effectiveness factor of the biofilm was always lower than one due to accumulation of product leading to higher concentrations within the biofilm than in the bulk. The generalized models developed for effectiveness factors under various conditions of inhibition can be used as a predictive tool in design of wastewater treatment systems.     

Toxic epidermal necrolysis--a retrospective study

BACKGROUND: Toxic epidermal necrolysis (TEN) is a severe, idiosyncratic, exfoliative disease of the skin and mucous membranes. The treatment of this condition is controversial. High-dose corticosteroid therapy has been the most commonly advocated treatment, but, more recently, this has changed to a no-steroid protocol. These conflicting treatments prompted us to evaluate retrospectively our protocol. METHODS: The patients admitted to the hospital from 1989 to 1995 with a clinical diagnosis of TEN were included in the study. These patients were given systemic steroids, prophylactic antibiotic, and supportive measures. RESULTS: The patients belonged to both sexes with an average age of 34 years. The average area of involvement was 85.62%. All the patients made an uneventful recovery without any evidence of sepsis. CONCLUSIONS: Treatment with systemic steroids is useful in the management of TEN, and there is no need for a burn care center.     

Toxic shock syndrome after mastoidectomy

PURPOSE: To evaluate the effect of topical aqueous humor suppressants on the absorption of intravitreal perfluorocarbon gases. METHODS: Sulfur hexafluoride or perfluoropropane was injected intravitreally in five rabbits. Time to gas disappearance was measured in eyes treated with topical aqueous humor suppressants and in those not treated. RESULTS: The mean time (+/- SD) to disappearance of 0.4 cc of sulfur hexafluoride was 5.6 +/- 0.9 days, which was prolonged by 43% to 8.0 +/- 0.7 days with topical aqueous humor suppressants (P = .009). The mean time (+/- SD) to disappearance of 0.2 cc of perfluoropropane was 18.4 +/- 1.9 days, which was prolonged by 55% to 28.6 +/- 2.7 days with topical aqueous humor suppressants (P = .009). CONCLUSION: Aqueous suppressants prolong sulfur hexafluoride and perfluoropropane intravitreal gas bubble duration in rabbits.     

Toxic shock-like syndrome after acupuncturation

A 80-year-olkd male was admitted to our hospital because of severe pain and swelling on his left lower leg on January 23, 1996. He had received an acupuncture to both legs because of intermittent claudication once a week from July, 1995 to January 18, 1996. On the next day of the last acupuncture, pain and swelling on his left leg appeared. On admission, his left leg showed diffuse swelling and redness with blisters. We diagnosed this patient as toxic shock-like syndrome (TSLS), based on the rapid exacerbation of the skin changes, necrotizing superficial fasciitis, multiple organ failure with shock, and the detection of group A streptococcus from culture samples obtained from both skin blister and necrotic fascia. He recovered from the disease by amputation of the involved leg and antibiotic therapy. Acupuncture could have been the cause of streptococcal infection.     

"Toxic sock" syndrome

For several months, a 17-year-old male athlete noticed that his feet had an itchy, burning sensation at the heels and toes. His foot odor had become so malodorous (somewhat akin to rotting fish) that he would not remove his shoes except immediately before washing his feet. Washing made the odor somewhat milder, but only for a short time. The patient had tried an over-the-counter "athlete's foot" powder without results. He had no other health problems and was not taking any medication. The accompanying figure shows the toes of his right foot.