Impact of Naringenin on Oxytetracycline-Mediated Oxidative Damage in Kidney of Rats

The aim of this study was to investigate the effect of naringenin on oxytetracycline-induced nephrotoxicity in rats. Oxytetracycline (200 mg/kg body weight, ip) was administered in 0.5ml of sterile physiological saline for 15 days, resulting in a significant increase in serum urea and creatinine and reduction in creatinine clearance. A significant increase in lipid peroxidation markers (TBARS and lipid hydroperoxide) and decrease in antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and low molecular weight antioxidants (vitamin C, vitamin E, and reduced glutathione) levels were also observed in oxytetracycline-treated rats. The oral administration of naringenin (50 mg/kg body weight) attenuated the oxytetracycline-induced nephrotoxicity by significantly decreased levels of serum urea and creatinine with the significant normalization of creatinine clearance. Upon the administration of naringenin, the depleted renal antioxidant defense system (enzymatic and non-enzymatic antioxidants) was significantly increased in rats treated with oxytetracycline. These biochemical observations were supplemented by histopathological examination of kidney section. The present results suggest that the supplementation of naringenin might be helpful to alleviate the oxytetracycline-induced oxidative injury in kidney.     

高灵敏度荧光光度法测定人血清中的磷脂

目的:探讨以稀土离子络合物作为荧光探针测定血清中的磷脂及荧光增强的机理。方法:在pH8.00的Tris-HCl缓冲溶液中,土霉素可以和铕离子生成二元络合物,从土霉素到铕离子发生能量转移,发射出铕离子位于612 nm处的特征荧光。加入磷脂后,磷脂同样可以把能量转移给铕离子。结果:铕离子位于612 nm处的特征荧光强度显著增强,且增强的荧光强度与加入磷脂的浓度成正比。在最佳实验条件下,测量的线性范围为4.00×10-7～1.00×10-5mol.L-1,检测限为2.60×10-7mol.L-1。平均回收率为98.2%～103.0%。结论:该方法操作简单,可以较好的避免共存物质的干扰,并被成功地应用于人血清样品中磷脂的测定。测量结果与临床上常用的以钼蓝为显色试剂的分光光度法相比,无显著性差异。     

紫外线诱变育种提高土霉素菌种的生产能力

以土霉素产生菌龟裂链霉菌（Ｓｔｒｅｐｔｏｍｙｃｅｓｒｉｍｏｓｕｓ）Ｌｆ－２为出发菌株，经紫外线处理后，再经摇瓶初筛、复筛获得高效价菌株Ｕｆ－３。又经Ｌ９（３４）的正交设计实验，确定了Ｕｆ－３的最佳培养基配比，使其摇瓶效价提高１５．２％。在２０ｍ３罐上放大试验，与出发菌株相比发酵效价提高１７．４％，发酵指数提高２３．９％     

氧四环素腹腔注射制备大鼠非酒精性脂肪肝模型的实验研究

寻找一种经济、高效的制备大鼠非酒精性脂肪肝动物模型的方法。采用高脂饮食与腹腔注射氧四环素相结合的方案。在模型组于造模开始后的第2、4、8周末及对照组在第8周末，分别检测大鼠血清ALT、AST、TG、TC、丙二醛（MDA）、超氧化物岐化酶（SOD），肝脏TC．、TC、MDA、SOD水平及肝组织学改变。2周末、4周末和8周末模型组血清中的ALT、AST、TG、TC和MDA升高，SOD降低；肝脏组织中的TG、TC和MDA升高，SOD减低；与对照组相比均有统计学意义；肝组织病理学检查显示第2周末和第4周末表现为脂肪肝性肝炎病变为主，8周末可出现轻度肝纤维化。采用高脂饮食结合腹腔注射氧四环素的方法是一种制备非酒精性脂肪肝模型理想方法之一。     

Possible cytostatic action of tetracyclines in the treatment of tumors of the nasopharynx and larynx

Summary 218 patients with a tumor of the larynx or nasopharynx, who had been treated with various forms of combination therapy, and who had died in the period 1964-1976, were studied retrospectively to see if addition of tetracyclines to the treatment had influenced survival time. The patients who received tetracycline appeared to have lived longer. Further, from analysis of all patients from 1–10 years after treatment, it appeared that addition of methotrexate to conventional therapy (surgery, radiation) had worsened the prognosis, in contrast to tetracycline. Tetracycline alone gave slightly better results than in the control group. It had also considerably improved survival in patients who had also received methotrexate. Inhibition of mitochondrial protein synthesis by the tetracyclines is proposed as possible mechanism of the effect. It is suggested that tetracyclines may also be valuable in the treatment of other types of cancer, especially because they appear to be nontoxic as far as bone-marrow function is concerned.Part of the results has previously been published [10].     

Exposure of a Tropical Soil to MG/KG of Oxytetracycline Elicits Hormetic Responses in the Catabolic Activities of Its Microbial Community

Many farmers in developing countries protect their crops with oxytetracycline and fertilize their farmlands with manure from animals that received this drug as growth promoter. In this study, a tropical soil was exposed to 0.1 mg kg(-1), 1 mg kg(-1), and 10 mg kg(-1) of oxytetracycline for 22 days to evaluate whether this antibiotic alters the capacity of a soil microbial community to metabolize 31 carbon sources. The communities exposed to 1 and 10 mg kg(-1) of oxytetracycline exhibited reduced catabolic activities for 3 and 6 substrates, respectively. In contrast, the communities exposed to 0.1 mg kg(-1) of oxytetracycline showed higher catabolic activities than the controls and the other two treatments for 19 substrates. These data reveal a hormetic response at the community level not previously described for soil bacteria and oxytetracycline.     

Effects of Oxytetracycline on the Mechanical Properties of Bone and Skin in Young Rats

The influence of the tetracycline antibiotics on growing bones has been disputed. In the present study 58 young male rats were given intraperitoneal injections twice a day for 2 weeks; half of the rats received oxytetracycline and the other half placebo. The concentration of oxytetracycline in plasma was comparable with therapeutic levels in man. Compared with the control animals the oxytetracycline rats had, at the end of the medication period, a significantly lower weight (7 per cent), shorter bones (1-2 per cent), lower bending strength of both the tibia diaphysis (9 per cent) and the distal femur metaphysis (22 per cent) and even lower tensile strength of intact (17 per cent) and sutured (27 per cent) skin. The effect of oxytetracycline seems to be reversible as no differences between the two groups could be detected 1-3 weeks after the end of medication.     

氮离子注入土霉素产生菌的诱变育种

目的获得土霉素产生菌的高产菌株,提高发酵单位。方法用土霉素产生菌龟裂链霉菌经分离纯化的2810#菌株的分生孢子作处理样品,使用发射能量为15×103eV的氮离子束对其进行诱变处理,氮离子的注入剂量为每平方厘米注入2.0×1015个离子,分生孢子死亡率为98.2%。结果诱变处理后经摇瓶筛选得到1082#高产菌种,其摇瓶发酵单位提高11.2%,投入发酵生产后平均发酵单位提高8.9%。结论氮离子注入方法对提高龟裂链霉菌的产量正向突变频率有明显效果。     

Effects of Oxytetracycline on Solubility and Synthesis of Collagen in Young Rats

In a recent study we demonstrated that the antibiotic oxytetracycline reduces both growth and mechanical strength of bone and skin in young rats. the present study deals with the effects of 14 days of oxytetracycline medication on salt solubility of collagen (cross-linking) and conversion of ¹⁴C-proline to ¹⁴C-hydroxyproline in collagen (synthesis). At the end of the medication period, significantly higher solubility of collagen was found in the femurs and skin of rats receiving oxytetracycline than in controls. No effect of the antibiotic on the rate of collagen synthesis could be demonstrated. These findings may indicate that oxytetracycline in young rats causes reduced mechanical strength of bone and skin by interfering with the cross-linking of collagen.     

高效液相色谱法测定土霉素片的含量

目的对土霉素片进行质量控制。方法采用高效液相色谱法测定土霉素片的含量。色谱柱为Agilent C18柱(250 mm×4.6 mm,5μm),流动相为0.1%磷酸-甲醇(42∶58),检测波长为254 nm,柱温为35℃。结果土霉素进样量在1.6～2.4μg范围内与峰面积呈良好线性关系,平均回收率为99.88%,RSD=0.31%(n=6)。结论该方法简便易行、重现性好,可用于土霉素片的质量控制。