Nephrotoxicity of dactimicin, a novel pseudo-disaccharide aminoglycoside possessing the N-formimidoyl group, compared with that of astromicin, amikacin and other aminoglycoside antibiotics in animals

The nephrotoxicity of dactimicin, the first aminoglycoside possessing the N-formimidoyl group, was compared with that of astromicin and, in part, amikacin, ribostamycin, kanamycin and gentamicin as reference aminoglycoside antibiotics. When a dose of 200 mg/kg was given intramuscularly to dehydrated mice, dactimicin caused no change of BUN and serum creatinine, while reference aminoglycosides caused significant elevations of the parameters. In the urinalysis of rats at doses of 40 and 80 mg/kg per day for 11 days or 21 days, dactimicin caused little changes in urinary parameters except for nucleated cells and NAG. In a detailed comparison between dactimicin and astromicin at 20, 40, 80, 120, 180 and 270 mg/kg for 11 or 30 days, dactimicin induced fewer changes in nucleated cells and NAG at high dosages. While dactimicin and astromicin caused no significant changes in BUN and serum creatinine at dosages of 20-270 mg/kg, histological observations using light and electron microscopes revealed that dactimicin consistently showed fewer lesions on the proximal tubular cells than those of astromicin for all dosages. When injected intramuscularly in rats, dactimicin and astromicin showed a similar distribution in the blood and main organs, except for the kidney, in which renal accumulation of dactimicin was about 60% of that of astromicin. Dactimicin slowly degraded in vitro and in vivo to give fortimicin B as a main product which was accumulated in the kidney. Through comparative studies with astromicin, it was disclosed that the N-formimidoyl group of dactimicin did not increase but decreased the nephrotoxicity, probably by suppressing reabsorption of dactimicin via proximal tubular cells.     

Renal disease in rheumatoid arthritis.

N-Acetyl-beta-D-glucosaminidase (NAG) is a sensitive indicator of renal damage. When the urinary NAG levels of 60 patients with rheumatoid arthritis (RA) were measured a highly significant difference was detected between the mean urinary NAG excretion of the patients with RA (341 +/- 294-92 nmol h-1 mg creatinine-1) and that of 60 matched controls (67-53 +/- 16-93 nmol h-1 mg creatinine-1). In 10 patients studied no correlation could be shown between the urinary NAG levels and levels in either serum or synovial fluid. A significant positive correlation was noted between urinary NAG excretion and disease activity as estimated by the Lansbury activity index, the Ritchie articular index, and the haemaglobin level. An abnormally raised urinary NAG excretion was detected in eight out of 20 previously untreated patients with RA, which suggested that the rheumatoid process may affect renal function.     

Protective effect of fleroxacin against the nephrotoxicity of isepamicin in rats

The protective effect of fleroxacin on isepamicin-induced nephrotoxicity was investigated. Wistar rats were administered either fleroxacin 100 mg/kg orally, isepamicin 300 mg/kg subcutaneously, or fleroxacin and isepamicin in combination for 14 d. The animals given 300 mg/kg of isepamicin showed a significant increase in urine N-acetyl-beta-D-glucosaminidase (NAG) levels as compared with the control animals which received saline (p<0.01). However, the increase in NAG level was markedly less when isepamicin was administered in combination with fleroxacin (p<0.01). Fleroxacin alone had no effect on urine NAG activity. Serum creatinine and blood urea nitrogen (BUN) levels were significantly higher in animals treated with isepamicin alone than in the control animals (p<0.01) or animals receiving the isepamicin fleroxacin combination (p<0.01). Histopathologically, fleroxacin induced very few cellular alterations, but considerably reduced the manifestation of typical signs of isepamicin nephrotoxicity. This investigation demonstrates that fleroxacin protects animals against isepamicin-induced nephrotoxicity.     

Synergistic activity of astromicin and beta-lactam antibiotics against Pseudomonas aeruginosa in vitro and in vivo

Synergistic activity of astromicin and an antipseudomonal beta-lactam antibiotic such as piperacillin, cefsulodin or carbenicillin against Pseudomonas aeruginosa was demonstrated in vitro and in vivo. Synergy in vitro was observed more often when astromicin was combined with piperacillin or cefsulodin than when it was combined with carbenicillin. The combination of astromicin with piperacillin showed a bactericidal activity against Pseudomonas aeruginosa at a bacteriostatic concentration of each antibiotic alone. The synergy observed in vitro was reproduced against experimental mouse infections, and the astromicin-piperacillin or cefsulodin combination produced significantly greater protective effects than the single use of individual antibiotics.     

注射用硫酸阿司米星多剂量给药在健康人体的药代动力学

目的 研究注射用硫酸阿司米星(氨基糖苷类抗生素)多剂量给药在健康人体的药代动力学.方法 10名受试者恒速静脉滴注硫酸阿司米星200 mg,30 min,每日2次,间隔12 h,连续7 d.在第1 d和第7 d分别在不同时间取静脉血,收集尿样,给药第4～6 d采取谷浓度.用柱前衍生化-荧光HPLC法测定血药、尿药浓度.结...     

Proximal tubule damage in patients treated with gentamicin or amikacin

The present study aimed to determine the relationships between time of administration and dose of aminoglycosides, the extent of proximal tubule damage, evaluated by the urine N-acetyl-beta-D-glucosaminidase (NAG) activity, and to compare proximal tubule dysfunction in the patients treated with gentamicin and those receiving amikacin. The measurement of activity of NAG in urine was chosen to monitor of proximal tubule function. The studies were performed in 25 patients, who had to be administered gentamicin or amikacin by intramuscular injections. In both groups, the maximum NAG activities in urine were detected most frequently after the 7th day of the therapy. A significant difference in NAG activities in urine was noted between the values observed in the course of treatment with aminoglycosides and those determined before start of the treatment. NAG activity in urine significantly decreased following discontinuation of aminoglycoside antibiotic administration. The activities did not decrease quite to the pretreatment level but the remaining difference proved to be insignificant. In the course of aminoglycoside treatment, 7 patients demonstrated an increase in serum creatinine levels exceeding 0.4 mg%. It should be stressed that no pronounced differences in nephrotoxicity and, in particular, in their potential to induce injury to the proximal tubule have been disclosed between gentamicin and amikacin. Their significant, damaging effect on integrity of proximal tubule was demonstrated, which was evidenced by the clear increase in urinary NAG activity during administration of either drug. Nevertheless, only in a small fraction of such cases (12-16%), the increase promoted development of renal insufficiency, usually of a transient character. Monitoring of the increase in urinary NAG activities in line with observations on creatinine levels permits to distinguish a subgroup of patients who may be suspected of development of overt nephrotoxicity. In such cases cessation of aminoglycoside administration is required.     

注射用硫酸阿司米星单剂给药在健康人体的药代动力学

目的 研究注射用硫酸阿司米星(胺基糖苷类抗生素)在中国健康受试者单剂量给药的药代动力学.方法 采用随机、三交叉、拉丁方设计,12名受试者随机分为3组,先后静脉滴注3个剂量(150,200,250 mg)阿司米星.收集的血、尿样本,用柱前衍生化高效液相色谱-荧光法测定其血药浓度.结果 3个剂量组(150,200,250 nag)主要药代动力学参数:C_(max)分别为(11.27±2.65),(15.83±3.14),(21.97±3.67)mg·L~(-1);t_(1/2β)分别为(2.56±0.72),(2.97±1.30),(2.66±1.39)h;AUC_(0-t)分别为(30.92±8.49),(39.58±11.57),(47.31±11.59)mg·h·L~(-1);AUC_(0-∞)分别为(31.78±8.73),(40.50±11.56),(48.20±11.95)mg·h·L~(-1);V_c分别为(11.49±2.61),(10.69±1.52),(10.20±1.93)L;CL分别为(5.33±2.03),(5.49±1.51),(5.68±1.35)L·h-1.3种剂量12 h原型药物尿中累积排泄百分率分别为(78.75±7.00)%,(78.95±12.57)%,(79.94±10.28)%.结论 不同给药剂量的阿司米星主要药代动力学参数呈线性分布特性,药物主要通过肾脏排泄,3个剂量消除过程基本一致.     

Biosynthesis of astromicin and related antibiotics. I. Biosynthetic studies by bioconversion experiments

Biosynthesis of astromicin, a unique pseudodisaccharide aminoglycoside antibiotic containing 1,4-diaminocyclitol component, was investigated by isolating a variety of possible precursor compounds from mutants of Micromonospora olivasterospora in which biosynthetic pathways for astromicin were blocked. Washed mycelia of M. olivasterospora mutants converted these compounds to astromicin, which was detected by thin-layer chromatography. Since astromicin possesses one glycyl and three methyl groups, [14C]glycine and [14C]methionine should be incorporated into precursors to form astromicin. To confirm the biosynthetic pathway, formation of labeled astromicin from the precursors was examined using [1-14C]-glycine or [methyl-14C]methionine. From above results, we propose the biosynthetic pathway for astromicin as shown in Fig. 2.     

Inhibition by Lithium of Neomycin-Induced Release of N-Acetyl-β-glucosaminidase in the Rat Heart

Abstract: The effects of neomycin, lithium and concurrent therapy of these drugs on subcellular distribution of lysosomal enzyme, N-acetyl-β-glucosaminidase (NAG) in the heart was studied. Released activity of NAG was used as a marker for assessing myocardial lysosomal integrity. The activity of NAG was determined in non-sedimentable and sedimentable fractions after centrifugation of the tissue extracted for assessment of the subcellular distribution of the lysosomal enzyme. Daily intraperitoneal injection of 100 mg/kg/day of neomycin increased the ratio of the non-sedimentable activity (free) to the non-sedimentable plus sedimentable activities (total) of NAG. Daily intraperitoneal injection of lithium decreased the total activity of NAG but did not affect the ratio of free: total activities of the enzyme. Lithium in doses of 2 and 4 mM/kg/day one hour prior to neomycin reduced the neomycin-induced enhancement of the ratio of free: total activity of NAG. Neomycin like other aminoglycosides altered the acidic phospholipid metabolism in lysosomal membranes and/or impairment of some important lysosomal functions. In this regard, the protective effects of lithium may be due to interference of this ion with phosphoinositide cycle.     

糖尿病患者尿酶变化及意义

应用速率法检测６０例糖尿病（ＤＭ）患者的尿Ｎ－乙酰－β－Ｄ－氨基葡萄糖苷酶（ＮＡＧ）、碱性磷酸酶（ＡＬＰ）、ｒ－谷氨酰转肽酶（ＧＧＴ）活性。结果显示ＤＭ患者尿ＮＡＧ活性明显升高，且与尿白蛋白排泄率（ＵＡＥＲ）呈正相关，并可先于ＵＡＥＲ的增加而出现。提示尿ＮＡＧ活性测定可作为间接反映肾小球滤过膜功能、筛查糖尿病早期肾病的一项敏感指标。     

Enhancement of high dose cyclosporin A toxicity by frusemide

Adult Sprague-Dawley rats were given cyclosporin A (CyA), frusemide (Fr) or both drugs daily for 14 days. The doses of CyA (50 mg/kg) and Fr (5 mg/kg) were approximately 3-6 times and twice respectively those used in man. Fr on its own produced a diuresis lasting approximately 3 hr. This was characterized by a 10-fold increase in urine flow rate, a 40-fold increase in the rate of sodium excretion, and by 2- and 4-fold increases in urea and creatinine clearance rates, respectively. In addition, there was a doubling in urinary N-acetyl-beta-D-glucosaminidase (NAG) activity. After 4 days of combination treatment with CyA and Fr, the diuretic-induced increases in urine flow rate, sodium excretion and urinary NAG activity were similar to those following frusemide alone. However, urea and creatinine clearances did not increase during the diuresis. Fr itself did not impair renal function, but rats receiving only CyA did show elevations in serum urea and creatinine, with reductions in clearance rates, which progressed with time. There was also an increase in NAG enzymuria. When the two drugs were exhibited together, renal function was more severely impaired. All animals given CyA showed proximal renal tubular cell vacuolation: in half the damage was confined to the straight segment, while the rest showed additional severe convoluted segment change. Renal function was most abnormal in those rats in which both segments were affected. All animals given both drugs showed both straight and convoluted tubular abnormalities and a 2-fold increase in serum CyA levels. CyA-induced disturbances in hepatic function and lymphoid tissue atrophy were unaffected by the addition of Fr, nor did Fr affect the immunosuppressive action of CyA.     

Nephrotoxicity of piperacillin combined with furosemide in rats

Nephrotoxicity of piperacillin (PIPC) was evaluated in rats after combined administration with furosemide. After intravenous administration of PIPC (1600 mg/kg), the rats showed no change in urinalysis, biochemical analysis of plasma and histopathological analysis. The rats receiving furosemide (100 mg/kg) showed elevation of urinary NAG, BUN and creatinine concentrations, and showed slight degeneration of the renal proximal tubules. The rats receiving PIPC (1600 mg/kg) and furosemide (100 mg/kg) showed elevation of BUN and creatinine concentrations, and showed slight degeneration of the proximal tubules. These changes were comparable to those in rats receiving furosemide alone. The rats receiving cephaloridine (1600 mg/kg) showed elevation of urinary protein, BUN and creatinine concentrations, and showed moderate degeneration and necrosis of the proximal tubules. The nephrotoxicity was enhanced by combination with furosemide. In conclusion, no enhanced effect of nephrotoxicity was observed by combination of PIPC with furosemide.     

Urinary N-acetyl- beta-D-glucosaminidase activities in patients with renal disease.

Urinary N-acetyl-beta-D-glucosaminidase (NAG) activities were assayed in every urine void throughout 24 hours in 17 normal people and in four patients with renal disease. The variation in NAG activity due to changing rates of urine flow was almost eliminated by factoring enzyme activity by the urinary creatinine concentration. Random samples of urine may thus be used for assay. The results of NAG assay in 36 patients with acute and chronic renal diseases showed that NAG was a sensitive indicator of renal damage. This simple test may be valuable in detecting or monitoring renal disease.     

Further studies of the response of kidney Lysosomes to aminoglycosides and other cations

Rat renal cortical lysosomes were isolated in 0.3 M sucrose containing 1 mM EDTA by differential centrifugation. Lysosomes were incubated in isotonic sucrose or isotonic glycine with various concentrations of endogenous and exogenous compounds at 37° for 1 hr. Lysosomes were resedimented, and the N-acetyl-β-glucosaminidase (NAG) activity was measured in the supernatant fraction and the disrupted pellet and the percentage of total NAG released was calculated. Gentamicin and its C₁ and C₂ components had similar potencies for inhibiting NAG release from lysosomes at low concentrations. The release of alpha-galactosidase and beta-galactosidase from lysosomes was also inhibited by streptomycin and gentamicin. Mepacrine at low concentrations stabilized lysosomes and at high concentrations disrupted lysosomes. This drug also enhanced the effect of low concentrations of gentamicin on lysosomes. Inositol hexaphosphoric acid was a potent antagonist of the effect of low concentrations of gentamicin and mepacrine on lysosomes. Rats were treated with gentamicin at doses of 40, 80 and 160 mg/kg for 1 and 3 days. NAG excretion in gentamicin-treated groups as compared to saline controls was unchanged at day 1. Only the 160 mg/kg treatment group showed a tendency toward elevated renal cortical NAG at day 1 (P < 0.06). All treatment groups had elevated renal cortical NAG at day 3, while the 160 mg/kg group also had elevated NAG excretion. Lysine, arginine, l-canavanine and polymyxin B all affected NAG release from lysosomes in vitro. Lysine enhanced the disruptive effect of high gentamicin concentrations on lysosomes. Ferric and ferrous ions, tested over widely varied concentrations, inhibited NAG release at low concentrations while enhancing NAG release at high concentrations. We therefore conclude that the nephrotoxicity of aminoglycoside and other endogenous and exogenous renally excreted cationic compounds may be produced by their effects on lysosomes in the proximal renal tubule.     

Biosynthesis of astromicin and related antibiotics. II. Biosynthetic studies with blocked mutants of Micromonospora olivasterospora

An inosamine-idiotrophic mutant, KY11559, which produced no astromicin unless scyllo-inosamine was added to the fermentation medium, was isolated from Micromonospora olivasterospora. Biotransformation studies were performed with resting cells of this mutant and compounds assumed to be precursors of 1,4-diaminocyclitol (fortamine). Scyllo-inosose, scyllo-inosamine and FU-10 were converted to astromicin. A number of mutants blocked in the biosynthesis of astromicin were developed from M. olivasterospora, and the intermediates accumulated by these mutants were isolated and identified. Twenty-five blocked mutants were classified into 10 groups, based on their complementation patterns by cosynthesis experiments. Further, utilizing these blocked mutants and the isolated compounds, biotransformation analyses were performed. The results showed that the amination at position 4 in fortamine occurred after formation of the pseudodisaccharide. Subsequently, the aminosugar and aminocyclitol moieties were aminated, methylated, dehydroxylated, epimerized and acylated to produce astromicin. Thus it was demonstrated that the astromicin biosynthetic pathway has a unique feature which is not found in the biosynthesis of other aminoglycoside antibiotics.     

Urinary N-acetyl-beta-D-glucosaminidase and beta 2-microglobulin in 'itai-itai' disease

N-acetyl-beta-D-glucosaminidase (NAG) activity in urine was measured in patients with 'itai-itai' disease, from chronically advanced cadmium poisoning. Elevation of NAG activity, however, was not so marked as that of beta 2-microglobulin (beta 2-MG) in the urine of patients and suspected patients. We conclude that the beta 2-MG test is more valuable than the NAG test for evaluating the severity of the renal tubular damage in chronically advanced cadmium (Cd) poisoning.     

海洛因依赖者尿微量蛋白联合尿酶检测分析

目的：探讨尿微量蛋白联合尿酶检测在海洛因依赖者中的临床意义。方法：对50例正常对照组和50例海洛因依赖组测定尿N-乙酰-β-D-氨基葡萄糖苷酶（NAG）、视黄醇结合蛋白（RBP）、微量白蛋白（mALB）和尿转铁蛋白（TRF）,同时检测尿肌酐。结果：正常对照组尿NAG／Cr为（0．72±0．33）U／mmoL,RBP／Cr为（9.46±4．81）μg／mmoL,mALB为（5．22±3．17）mg／L,TRF／Cr为（0．07±0．04）mg／mmoL;海洛因依赖组尿NAG／Cr、RBP／Cr、mALB及TRF／Cr值分别为（10．18±10．01）U／mmoL、（156．75±198．68）μg／mmoL、（30．65±26．38）mg／L、（1．92±3．02）mg／mmoL,与正常对照组比较,差异性显著（P〈0．01）。两项指标联合检测,其阳性率分别为：NAG＋mALB82％,NAG＋TRF76％,NAG＋RBP88％。结论：联合检测尿NAG与RBP是诊断海洛因依赖早期肾损害的最灵敏与可靠的实验室指标。     

A study on the prophylactic effect of cefotaxime against postoperative infections in the obstetrical and gynecological field

Prophylactic effect of cefotaxime (CTX) against postoperative infection at a dose level of 2 g intravenous per day for 5 days was investigated using fever index in patients who underwent abdominal cesarean section, abdominal simple panhysterectomy or radical hysterectomy. The results obtained are summarized as follows. Total fever index values were 3.53 +/- 2.07 degree hours in a group receiving CTX for prophylactic purpose in abdominal cesarean section (n = 15), 22.25 +/- 0.19 degree hours in a group that had infections before cesarean section and was treated with CTX (n = 2), 3.79 +/- 3.87 degree hours in a group administered with CTX for prophylactic purpose in abdominal simple panhysterectomy (n = 13), at a low level of 3.10 +/- 3.60 degree hours in a group administered with CTX and astromicin (400 mg i.m. per day for 5 days) for prophylaxis in abdominal simple panhysterectomy (n = 13), and 6.72 +/- 3.14 degree hours in a group receiving CTX for prophylaxis in radical hysterectomy (n = 7). When daily fever index values were expressed as cumulative proportions (%) of total fever index, specific patterns were observed for different types of surgical procedures. As the results obtained in our current study as well as our previous study indicate, different antibiotics also influenced these patterns differently. No abnormal laboratory findings nor side effects attributable to CTX were observed.     

尿N-乙酰-β-D-氨基葡萄糖苷酶对监测甲氨蝶呤肾脏毒性的意义

目的 探讨尿N-乙酰-B-D-氨基葡萄糖苷酶(NAG)在监测类风湿性关节炎患者长期服用甲氨蝶呤导致肾脏毒性中的意义.方法 选择长期服用甲氨蝶呤的类风湿性关节炎患者61例,按服用年限分为0～1年组、1-3年组、3～5年组,选择年龄、性别匹配的正常人30例作正常对照组,所有研究人群均留取新鲜晨尿,用酶法检测NAG,同时测定尿肌酐以校正,并测定血尿素氮、血肌酐.结果 服用甲氨蝶呤不同年限的类风湿性关节炎患者的血清尿素氮和肌酐均在正常范围.患者尿微量白蛋白排出量虽略高于正常对照组,但不存在统计学差异;0～1年组、1～3年组患者尿α1-微球蛋白(α1-MG)排泄量较正常对照组无差异,而3～5年组较正常对照组存在统计学差异;患者尿NAG活性随服用甲氨蝶呤的时间的延长而增高,0～1年组与正常对照组无差异,1～3年组、3～5年组与正常对照组均存在统计学差异.结论 随着类风湿关节患者服用甲氨蝶呤的时间延长,尿NAG酶的活性也发生改变.尿NAG酶的检测灵敏度高,对监测服用甲氨蝶呤患者出现早期肾脏损害有应用价值.     

Combination effect of KW-2228 and aminoglycoside antibiotics on systemic infection in cyclophosphamide-treated tumor-bearing mice]

A modified recombinant human granulocyte colony-stimulating factor (rhG-CSF), KW-2228, has some excellent properties such as high specific activity in stimulating granulocyte colony-formation in vitro, great biological stability in plasma, good pharmacokinetic profile and high potency in granulopoiesis in normal mice in vivo. Recently, the application of G-CSF against infectious diseases has been considered, and some animal experiments have been carried out to support its clinical applications. Patients with underlying diseases such as leukemia and cancer often have recurrent infections because of reduced numbers or functions of neutrophils, which mediate an early stage of host defense. In out present study, we established a new method to evaluate in vivo potency of G-CSF in colon 26 tumor-bearing mice. By using the method, we examined combination effects of KW-2228 with aminoglycoside antibiotics against a systemic infection caused by Pseudomonas aeruginosa. KW-2228 (1 microgram/mouse/day) was administered (s.c.) once a day for 4 days before the bacterial infection was introduced in colon 26 tumor-bearing mice receiving cyclophosphamide 3 days after the transplantation of tumor. Antibiotics were administered (s.c.) 2 hours after the introduction of the bacterial infection. ED50 of gentamicin (GM) alone and that of the combination with KW-2228 were 40.7 mg/kg and 3.6 mg/kg, respectively. ED50 of astromicin (ASTM) alone and that of the combination with KW-2228 were 386 mg/kg and 17.8 mg/kg, respectively. Thus the combination therapy of KW-2228 with GM or ASTM exhibited excellent protective effects in comparison to the treatment with antibiotic alone.(ABSTRACT TRUNCATED AT 250 WORDS)