Assessment of renal function in the early stages of nephrotoxicity induced by iodinated contrast media

Measurement of Selected Renal Biochemical Parameters in Healthy Adult Donkeys Considering the Influence of Gender, Age and Blood Freezing

The reference values of the serum and urine biochemical parameters have not been well-studied in donkeys. This study aimed to assess the normal values of the selected renal biomarkers, such as: serum creatinine, blood urea nitrogen (BUN), albumin, total protein (TP), electrolytes and symmetric dimethylarginine (SDMA), urine protein concentration (UPC), urine protein/creatinine ratio (UPCR), the urine gamma-glutamyl transferase (GGTP)-to-creatinine ratio, serum creatinine-to-urine creatinine ratio (sCr/uCr), serum BUN-to-serum creatinine ratio (sBUN/sCr) and UPC-to-TP ratio, as well as the fractional electrolyte excretion of sodium (FENa) and potassium (FEK) in donkeys. The effects of age, gender and deep freezing of the serum material were investigated. Sixty-five healthy adult donkeys were involved in this study. The results showed higher BUN and TP values and lower albumin, UPCR, FENa and FEK levels in donkeys when compared to the reference values in horses. A significant gender relationship for creatinine and BUN was found. Age influenced the values of albumin, TP, potassium and chlorine. Potassium, sodium and SDMA did not show significant concentration changes after freezing. The study results demonstrated that horse reference range values for some parameters cannot be applied to donkey samples. Only a few of the serum parameters were not affected by freezing, and this should be taken into account when storing biological materials.

Effects of benfotiamine and coenzyme Q10 on kidney damage induced gentamicin

OBJECTIVE

Gentamicin (GM) is an effective antibiotic against severe infection but has limitations related to nephrotoxicity. In this study, we investigated whether benfotiamine (BFT) and coenzyme Q10 (CoQ10), could ameliorate the nephrotoxic effect of GM in rats.

METHODS

Rats were divided into five groups. Group 1 and 2 served as control and sham respectively, Group 3 as GM group, Group 4 as GM+CoQ10 and Group 5 as GM+BFT for 8days. At the end of the study, all rats were euthanized by cervical decapitation and then blood samples and kidneys were collected for further analysis. Serum urea, creatinine, cytokine TNF-a, oxidant and antioxidant parameters, as well as histopathological examination of kidney tissues were assessed.

RESULTS

Gentamicin administration caused a severe nephrotoxicity which was evidenced by an elevated serum creatinine, urea and KIM-1 level as compared with the controls. Moreover, a significant increase in serum malondialdehyde, reduced glutathione. Histopathological examination of renal tissue in gentamisin administered group, there were extremly pronounced necrotic tubules in the renal cortex and hyalen cast accumulation in the medullar tubuli. BFT given to GM rats reduced these nephrotoxicity parameters. Serum creatinine, urea, and KIM-1 were almost normalized in the GM+BFT group. Benfotiamin treatment was significantly decreased necrotic tubuli and hyalen deposition in gentamisin plus benfotiamin group. CoQ10 given to GM rats did not cause any statistically significant alterations in these nephrotoxicity parameters when compared with GM group but histopathological examination of renal tissue in GM+CoQ10 administered group, CoQ10 treatment was decreased necrotic tubuli rate and hyalen accumulation in tubuli.

CONCLUSION

The results from our study indicate that BFT supplement attenuates gentamicin-induced renal injury via the amelioration of oxidative stress and inflammation of renal tubular cells.

Garlic supplemented diet attenuates gentamicin nephrotoxicity ın rats

PURPOSE

To demonstrate the effect of a 4% pulverized garlic supplemented diet on the nephrotoxicity induced by gentamicin in rats.

MATERIALS AND METHODS

Twenty four healthy male Wistar rats, weighing between 220 - 260 grams, were divided into three groups. The rats were randomly assigned to either the gentamicin injection without garlic supplementation group (Group I, n = 8), gentamicin injection with garlic supplementation group (Group II, n = 8), and control group (Group III, n = 8). Urine from the rats was collected and the volume (mL), microalbumin (mg/L), creatinine (mg/dL), Na (mmol/L), K (mmol/L), Cl (mmol/L), P (mg/dL), N-acetyl glucosamine (NAG) (U/L) and pH values were measured. Then urea (mg/dL), creatinine (mg/dL), total protein (g/dL) and cystatin (mg/L) values were measured for the blood samples obtained from tail veins.

RESULTS

The median NAG value for the control group (52.050 U/L) was similar to value for Group II (56.400 U/L), which received gentamicin and the garlic diet. However, the median NAG value for Group I (77.030 U/L), which received gentamicin without garlic supplementation, was determined to be statistically significantly higher (p = 0.010) than the value for the control group. In addition, the mean cystatin value for Group II (1.360 U/L) was found to be statistically significantly lower than the value for the Group I (2.240 U/L) (p = 0.015).

CONCLUSIONS

In this study we showed the effect of 4% pulverized garlic supplemented diet for preventing nephrotoxicity induced by gentamicin in rats by using as parameters NAG in urine samples and cystatin C in serum samples.

Radiation therapy with concurrent chemotherapy for locally advanced cervical carcinoma: outcome analysis with emphasis on the impact of treatment duration on outcome

Objective. To assess the effectiveness and toxicity of carboplatin concurrent with pelvic external beam radiation and low-dose rate brachytherapy and to assess the impact that adherence to the treatment plan has on outcomes. Methods. Retrospective chart review of 56 patients treated from January 2001 to December 2010. Results. Median follow-up was 68 months. Optimal dose of radiation (ORT) was defined as a minimal cervical dose exceeding 70 Gy, point A dose of 80–90 Gy, and duration not exceeding 56 days. Only 50% received ORT. In multivariable analyses we only found ORT to be statistically significant predictor for progression-free survival (PFS) and overall survival (OS) (HR [95% CI] for non-ORT vs. ORT: 2.4 [1.2, 5.1], P = 0.014 for PFS and 2.2 [1.1, 4.6], P = 0.035 for OS). The 5-year PFS in patients who received ORT was better than that in patients who received non-ORT, 56% vs. 22% (95% CI: [36%, 72%] vs. [9%, 39%]). Patients who received ORT had a better 5-year OS as well (59% vs. 33%; 95% CI: [38%, 75%] vs. [16%, 51%]). Conclusion. Patients with locally advanced cervical cancer treated with weakly carboplatin or cisplatin, teletherapy, and low dose-dose rate brachytherapy have poorer outcomes when treatment duration is prolonged.

A randomized comparison of cisplatin and oral vinorelbine as radiosensitizers in aged or comorbid locally advanced cervical cancer patients

OBJECTIVE

Chemoradiation with cisplatin is considered the standard of care for patients with locally advanced cervical cancer; however, cisplatin could be difficult to use in aged patients or patients with comorbidities such as diabetes mellitus and blood hypertension; hence, it is important to investigate nonplatinum drugs for radiosensitization. In addition, oral cytotoxics may overcome the drawbacks of intravenous infusions and could be of easier administration.

METHODS

In this small randomized trial, we tested cisplatin against oral vinorelbine as radiosensitizers in these patients. A total of 39 patients 65 years or older or diabetic and hypertensive patients of any age were randomized to cisplatin or oral vinorelbine at 40 mg/m² or 60 mg/m², respectively. Both drugs were administered weekly for 6 courses during pelvic external-beam radiotherapy and brachytherapy radiation. Efficacy and safety were assessed.

RESULTS

Nineteen patients received oral vinorelbine, and 20 patients received cisplatin. The median cumulative dose to point A was 80.8 Gy for both groups, and the overall treatment time was 48 (42-54) and 50 (43-55) days for vinorelbine and cisplatin groups, respectively. Patients in both arms received a median of 5 applications of chemotherapy. Treatment was well tolerated in both arms. The most frequent toxicity in both arms was lymphopenia grades 2 and 3. At a median follow-up time of 16 months (4-19), there were no differences in either progression-free survival or overall survival between groups.

CONCLUSIONS

Our results suggest that these patient populations can safely be treated with either cisplatin or navelbine as radiosensitizers; however, a larger randomized study is needed to demonstrate the noninferiority of oral vinorelbine as an easier and practical alternative for radiosensitization in cervical cancer.

Aged rats are susceptible to nephrotoxicity induced by iodinated contrast media

OBJECTIVE

The objective of this study is to evaluate the effect and mechanism of aging on iodinated-contrast-media-induced nephropathy in male rats.

METHODS

Twenty-four healthy male rats were initially divided into 12-month-old and 24-month-old age groups (adult and older age groups, respectively; n = 12/group); subsequently, each age group was randomly divided into saline control (NS) and contrast media (CM) groups (n = 6/group). CM (76% diatrizoate, 10 mL/kg b.w.) was given through the caudal vein. Urinary creatinine (Ucr) and serum creatinine (Scr) were detected by an automatic biochemical analyzer. The activities of renal malondialdehyde (MDA), superoxide dismutase (SOD), angiotensin-converting enzyme (ACE), angiotensin II (Ang II), and reduced form of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) were determined by spectrophotometric assays with commercially available kits according to the manufacturers' protocols. Renal histological changes were observed by hematoxylin and eosin staining and scored semiquantitatively.

RESULTS

In diatrizoate-injected aged rats, Scr, the activities of ACE, Ang II, MDA, and NADPH oxidase in renal tissues were significantly increased (p < 0.01). The histologic scores were higher in the aged animals with CM treatment than those of control or adult rats (p < 0.01). There was an increasing trend but no significant statistical difference in renal ACE, Ang II, MDA, and NADPH oxidase or histologic scores in adult CM-injected rats compared with control animals (p > 0.05).

CONCLUSIONS

Older age is an aggravating factor of iodinated-contrast-media-induced nephropathy in male rats. Oxidative stress and the renin-angiotensin system (RAS) may play an important role in nephrotoxicity induced by iodinated contrast media, especially in aged male rats.

A modified model of gentamicin induced renal failure in rats: toxicological effects of the iodinated X-ray contrast media ioversol and potential usefulness for toxicological evaluation of iodinated X-ray contrast media

Contrast-induced nephropathy (CIN) remains a serious complication in patients exposed to iodinated X-ray contrast media (ICM). Animal models of CIN are useful to further understand the mechanisms involved, identify novel biomarkers and evaluate potential differences between ICM. The current investigation was undertaken to modify the rat-gentamicin model for potential usefulness for toxicological evaluation of ICM. A dose-range finding study (50, 60 and 70 mg/kg body weight (bw)) of gentamicin was conducted over 4 consecutive days. Based on the kidney histopathology findings, a gentamicin dose of 70 mg/kg bw was chosen to investigate whether ICM would cause further renal damage. Following gentamicin treatment, this group was given a single administration of ioversol (6 gI/kg bw). Blood and urine samples were taken from all animals 3 days before the start of the study and at the end of treatment. Serum and urinary creatinine, urinary N-acetyl-β-D-glucosaminidase (NAG), γ-glutamyl transferase (GGT), total protein, and urine cytology were evaluated as biomarkers of renal damage. Histopathological examination of kidneys was performed. Histopathological examination of the kidneys revealed vacuolation, dilatation, and necrosis of the proximal tubules in the gentamicin-ioversol treatment group. These changes were not seen in the gentamicin-only treatment groups. Data on GGT and urinary epithelial cells show clear differences between rats treated with gentamicin alone versus gentamicin plus ioversol. These findings show that the modified rat-gentamicin model was able to demonstrate the nephrotoxic effect of ioversol.

Kidney tubular damage in the absence of glomerular defects in HIV-infected patients on highly active antiretroviral therapy

BACKGROUND

The emergence of kidney disease as an important comorbidity among human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) has emphasized the critical importance of early identification of patients at risk for kidney disease. Use of urine as a diagnostic medium may allow the noninvasive detection of incipient nephropathy in these patients.

METHODS

Here, we conducted cross-sectional and 1-year prospective studies of 424 HIV-infected patients on HAART without proteinuria or significant impairment of glomerular function. N-acetyl-β-D-glucosaminidase, γ-glutamyl transpeptidase, β(2)-microglobulin and α(1)-microglobulin were measured as indices of tubular damage, which was diagnosed when urinary concentrations of at least three tubular biomarkers exceeded the reference range. Risk factors associated with tubular damage were examined using multivariate logistic regression analysis.

RESULTS

Tubular damage was identified in 107 patients (25%), who were characterized by advanced age [odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01-1.07], high C-reactive protein (OR, 1.96; 95% CI, 1.26-3.14) and coexisting diabetes mellitus (OR, 3.97; 95% CI, 1.44-12.2). The use of tenofovir, the most likely tubulotoxic agent, was not statistically involved in this subclinical tubular damage. The 1-year follow-up study showed that a decrease in estimated glomerular filtration rate (eGFR) and incidence of proteinuria during the period were significantly higher in patients with than without tubular damage.

CONCLUSIONS

A quarter of HIV-infected patients receiving HAART had subclinical tubular damage, which was associated with a near-term decline in eGFR and higher incidence of proteinuria. Periodic monitoring of urinary biomarkers might facilitate the early identification of HAART patients predisposed to significant kidney disease.

Pharmacotherapy options for locally advanced and advanced cervical cancer

Cervical cancer continues to be a significant health burden worldwide. Globally, the majority of cancers are locally advanced at diagnosis; hence, radiation remains the most frequently used therapeutic modality. Currently, the value of adding cisplatin or cisplatin-based chemotherapy to radiation for the treatment of locally advanced cervical cancer is strongly supported by randomized studies and meta-analyses. Nevertheless, despite these significant achievements, therapeutic results are far from optimal; thus, novel therapies need to be investigated. A recent, randomized, phase III trial has shown for the first time that combination chemotherapy with cisplatin and gemcitabine concurrently with radiation improves parameters of survival over cisplatin alone and establishes a new standard for the management of locally advanced cervical cancer. On the other hand, advanced disease, presenting either as an International Federation of Gynecology and Obstetrics (FIGO) stage IVB or as persistent or recurrent to primary therapy without local curative options, remains a devastating group of diseases with no options other than palliative chemotherapy. Recent results from the GOG (Gynecologic and Oncologic Group)-204 study demonstrate that cisplatin-doublets with paclitaxel, vinorelbine, gemcitabine or topotecan only produce small improvements in survival, although with different toxicity patterns; hence, patient-related factors are important when choosing any one of these regimens. The role of targeted therapies both in locally advanced and advanced disease is promising, but still at an investigational stage.

Kidney injury molecule-1 expression in rat proximal tubule after treatment with segment-specific nephrotoxicants: a tool for early screening of potential kidney toxicity

Dose-response expression of kidney injury molecule-1 (KIM-1) gene in kidney cortex and its correlation with morphology and traditional biomarkers of nephrotoxicity (plasma creatinine and blood urea nitrogen, BUN) or segment-specific marker of proximal tubule injury (kidney glutamine synthetase, GSK) were studied in male rats treated with proximal tubule segment-specific nephrotoxicants. These included hexachloro-1:3-butadiene (HCBD, S(3) segment-specific), potassium dichromate (chromate, S(1)-S(2) segment-specific), and cephaloridine (Cph, S(2) segment-specific). Rats were treated with a single intraperitoneal (ip) injection of HCBD 25, 50, and 100 mg/kg, subcutaneous (sc) injection of chromate 8, 12.5, and 25 mg/kg; or ip injection of Cph 250, 500, and 1,000 mg/kg. KIM-1 gene showed a dose-dependent up-regulation induced by all segment-specific nephrotoxicants. Interestingly, magnitude of the up-regulation reflected the severity of microscopic tubular changes (degeneration, necrosis, and regeneration). Even low-severity microscopic observations were evidenced by significant gene expression changes. Furthermore, KIM-1 showed significant up-regulation even in the absence of morphological changes. In contrast, traditional and specific markers demonstrated low sensitivity or specificity. In conclusion, this study suggested KIM-1 as a sensitive molecular marker of different levels of tubular injury, and it is likely to represent a potential tool for early screening of nephrotoxicants.

NGAL is an early predictive biomarker of contrast-induced nephropathy in children

We hypothesized that neutrophil gelatinase-associated lipocalin (NGAL) is an early predictive biomarker of contrast-induced nephropathy (CIN). We prospectively enrolled 91 children (age 0-18 years) with congenital heart disease undergoing elective cardiac catheterization and angiography with contrast administration (CC; Ioversol). Serial urine and plasma samples were analyzed in a double-blind fashion by NGAL enzyme-linked immunosorbent assay (ELISA). CIN, defined as a 50% increase in serum creatinine from baseline, was found in 11 subjects (12%), but detection using increase in serum creatinine was only possible 6-24 h after CC. In contrast, significant elevation of NGAL concentrations in urine (135 +/- 32 vs. 11.6 +/- 2 ng/ml without CIN, p < 0.001) and plasma (151 +/- 34 vs. 36 +/- 4 without CIN, p < 0.001) were noted within 2 h after CC in those subjects. Using a cutoff value of 100 ng/ml, sensitivity, specificity, and area under the receiver-operating characteristic (ROC) curve for prediction of CIN were excellent for the 2-h urine NGAL (73%, 100%, and 0.92, respectively) and 2-h plasma NGAL (73%, 100%, and 0.91, respectively). By multivariate analysis, the 2-h NGAL concentrations in the urine (R (2) = 0.52, p < 0.0001) and plasma (R (2) = 0.72, p < 0.0001) were found to be powerful independent predictors of CIN. Patient demographics and contrast volume were not predictive of CIN.

Detecting early kidney damage in horses with colic by measuring matrix metalloproteinase -9 and -2, other enzymes, urinary glucose and total proteins

Background

The aim of the study was to investigate urine matrix metalloproteinase (MMP-2 and -9) activity, alkaline phosphatase/creatinine (U-AP/Cr) and gamma-glutamyl-transpeptidase/creatinine (U-GGT/Cr) ratios, glucose concentration, and urine protein/creatinine (U-Prot/Cr) ratio and to compare data with plasma MMP-2 and -9 activity, cystatin-C and creatinine concentrations in colic horses and healthy controls. Horses with surgical colic (n = 5) were compared to healthy stallions (n = 7) that came for castration. Blood and urine samples were collected. MMP gelatinolytic activity was measured by zymography.

Results

We found out that horses with colic had significantly higher urinary MMP-9 complex and proMMP-9 activities than horses in the control group. Colic horses also had higher plasma MMP-2 activity than the control horses. Serum creatinine, although within reference range, was significantly higher in the colic horses than in the control group. There was no significant increase in urinary alkaline phosphatase, gamma-glutamyltranspeptidase or total proteins in the colic horses compared to the control group. A human cystatin-C test (Dako Cytomation latex immunoassay^® based on turbidimetry) did not cross react with equine cystatin-C.

Conclusion

The results indicate that plasma MMP-2 may play a role in the pathogenesis of equine colic and urinary MMP-9 in equine kidney damage.

Radiosensitizers in cervical cancer. Cisplatin and beyond

Cervical cancer continues to be a significant health burden worldwide. Globally, the majority of cancers are locally advanced at diagnosis; hence, radiation remains the most frequently used therapeutical modality. Currently, the value of adding cisplatin or cisplatin-based chemotherapy to radiation for treatment of locally advanced cervical cancer is strongly supported by randomized studies and meta-analyses. Nevertheless, despite these significant achievements, therapeutic results are far from optimal; thus, novel therapies need to be assayed. A strategy currently being investigated is the use of newer radiosensitizers alone or in combination with platinum compounds. In the present work, we present preclinical information on known and newer cytotoxic agents as radiosensitizers on cervical cancer models, as well as the clinical information emanating from early phase trials that incorporate them to the cervical cancer management. In addition, we present the perspectives on the combined approach of radiation therapy and molecular target-based drugs with proven radiosensitizing capacity.

Follow-up of patients with contrast-induced nephropathy

In this chapter, we review the approach to following the patient after contrast is administered. We first discuss the clinical importance of renal injury for if there were no clinically significant consequences of this renal injury, we would have far less concern for the adequacy of follow-up. We next look at markers of renal injury and what tests are used in clinical practice to define contrast-induced nephropathy (CIN). Finally, we discuss the steps that should be taken in those who do develop CIN to limit the impact of the injury and protect them from future adverse events.

Effect of iodinated contrast agents on residual renal function in PD patients

BACKGROUND

Residual renal function (RRF) is an important predictor of outcome in peritoneal dialysis (PD) patients. Although increasing emphasis has been placed on preserving RRF, the nephrotoxicity associated with contrast medium administration in PD patients remains a controversial issue. In the present prospective study, we evaluated the evolution of RRF 2 weeks after iodinated contrast medium administration (ICMA) in a group of stable PD patients, and compared it with that in a non-treated control group of stable PD subjects.

METHODS

The study was conducted from January 2003 to October 2004. RRF was quantified by the average of 24 h urinary urea and creatinine clearance and peritoneal creatinine clearance (PcrCl) were analyzed, the levels of which were analysed prior to and 2 weeks following ICMA in 36 PD patients and also assessed at the same time points in a group of 36 PD non-ICMA control subjects, matched according to RRF characteristics. Two weeks following ICMA, the values for RRF, daily urine volume and PcrCl were assessed against those at baseline, and the evolution of RRF was compared between the two groups. In the ICMA group, this study was performed with adequate pre-hydration and a minimum dose of contrast medium.

RESULTS

Compared with baseline values, RRF, daily urine volume and PcrCl were not found to be significantly different 2 weeks after ICMA (7.0+/-4.3 vs 7.2+/-4.3 ml/min/1.73 m(2), P = 0.12; 1324+/-696 vs 1360+/-755 ml/day, P = 0.5; and 41.1+/-9 vs 40.6+/-9 l/week/1.73 m(2), P = 0.6, respectively). Following ICMA, variations in RRF and daily urine volume were found to be comparable with those of the control group (0.1+/-0.5 vs 0.1+/-0.5 ml/min/1.73 m(2), P = 0.9; 36+/-440 vs 40+/-493 ml/day, P = 0.8, respectively).

CONCLUSION

In this study, 2 weeks following ICMA, no accelerated decline in RRF was determined in stable PD patients with adequate pre-hydration, i.e. subjects treated under optimal circumstances compared with the control group.

Overview on the application of transcription profiling using selected nephrotoxicants for toxicology assessment

Microarrays allow for the simultaneous measurement of changes in the levels of thousands of messenger RNAs within a single experiment. As such, the potential for the application of transcription profiling to preclinical safety assessment and mechanism-based risk assessment is profound. However, several practical and technical challenges remain. Among these are nomenclature issues, platform-specific data formats, and the lack of uniform analysis methods and tools. Experiments were designed to address biological, technical, and methodological variability, to evaluate different approaches to data analysis, and to understand the application of the technology to other profiling methodologies and to mechanism-based risk assessment. These goals were addressed using experimental information derived from analysis of the biological response to three mechanistically distinct nephrotoxins: cisplatin, gentamicin, and puromycin aminonucleoside. In spite of the technical challenges, the transcription profiling data yielded mechanistically and topographically valuable information. The analyses detailed in the articles from the Nephrotoxicity Working Group of the International Life Sciences Institute Health and Environmental Sciences Institute suggest at least equal sensitivity of microarray technology compared to traditional end points. Additionally, microarray analysis of these prototypical nephrotoxicants provided an opportunity for the development of candidate bridging biomarkers of nephrotoxicity. The potential future extension of these applications for risk assessment is also discussed.

A phase I study of carboplatin concurrent with radiation in FIGO stage IIIB cervix uteri carcinoma

PURPOSE

Chemoradiation based on cisplatin, most commonly weekly, is the standard treatment of locally advanced cervical cancer; however, the nephrotoxic potential and the requirement for hydration of cisplatin somewhat restrains its use. The objective of this study was to determine the recommended dose of carboplatin when administered weekly during pelvic radiation (RT).

METHODS AND MATERIALS

Twenty-four histologically proven, International Federation of Gynecology and Obstetrics Stage IIIB patients were treated with standard pelvic RT concurrently with six weekly applications of carboplatin at the following dose levels: 100 mg/m(2), 116 mg/m(2), 133 mg/m(2), and 150 mg/m(2). Six patients per level were treated. Acute toxicity was assessed according to the Radiation Therapy Oncology Group Acute Radiation Morbidity Scoring Criteria. The recommended dose was defined as the one that was one level below the level at which dose-limiting toxicity was present in more than one-third of patients.

RESULTS

Between September 2001 and July 2002, 24 patients were accrued. All but two completed external beam radiotherapy and intracavitary treatment. The treatment was well tolerated. The median number of weekly applications of carboplatin was six, and the mean dose to points A and B was 85.6 Gy (range 75.2-91.6) and 62.9 Gy (range 58.2-74.6), respectively. RT was delivered within 41.7 days (range 33-70). Dose-limiting toxicity (leukopenia and/or neutropenia) was present in 50% of patients treated at the higher dose level (150 mg/m(2)). At the recommended dose of 133 mg/m(2), 33% of patients presented with Grade 3 leukopenia. At treatment completion, 75% of patients had a complete clinical response.

CONCLUSION

Carboplatin at 133 mg/m(2), weekly for 6 weeks, is a well tolerated and effective radiosensitizer in cervical cancer patients.

Glucose alters the susceptibility of mesangial cells to contrast media

RATIONALE AND OBJECTIVES

Diabetic patients frequently suffer contrast media-induced nephropathy. Hyperglycemia in diabetes mellitus causes gradual deterioration of glomerular mesangial cells (MCs) in the kidney. In this study, the authors investigated the response of rat MCs cultured in high-glucose medium to diatrizoate and iohexol, high- and low-osmolar contrast media, respectively.

METHODS

Isolated rat MCs were precultured under basal-glucose (5.5 mmol/L) and high-glucose (30 and 55 mmol/L) conditions for 24 hours to mimic hyperglycemia in diabetes mellitus and then were exposed to diatrizoate (40 and 80 mg I/mL) and iohexol (80, 120, 160 mg I/mL) for 2 hours. The cytotoxic effects of diatrizoate and iohexol were monitored by neutral red uptake in MCs. The protective effects of an antioxidant, d-alpha-tocopherol (Toc), on cytotoxicity of the contrast media were determined when MCs were precultured with Toc under high-glucose conditions or were exposed to the contrast media together with Toc. Peroxide levels in the cells exposed to the contrast media were analyzed by flow cytometry using dichlorofluorescin diacetate.

RESULTS

Exposure to both contrast media (diatrizoate and iohexol) induced a concentration-dependent decrease in viability of the cells precultured under basal-glucose conditions (5.5 mmol/L). Preculture under high-glucose conditions (30 and 55 mmol/L) augmented the cytotoxic effects of both contrast media. An increase in the intracellular peroxide level was detected after exposure to both contrast media. Preculture with Toc prevented augmentation of the cytotoxic effects of diatrizoate by the higher glucose concentration (55 mmol/L). The exposure to diatrizoate together with Toc also attenuated its cytotoxic effects. Toc showed no such protective effects against iohexol exposure.

CONCLUSIONS

These findings suggest that high-glucose conditions enhance the susceptibility of MCs to the cytotoxic effects of both contrast media; the enhanced susceptibility was in part attributable to oxidative stress caused by high-glucose conditions; diatrizoate exerted the cytotoxic effects by means of oxidative stress; and iohexol appeared to exert its cytotoxicity in a manner different from diatrizoate.